Fresh water generators produce fresh water for domestic and auxiliary use aboard ships by distilling or desalinating sea water. They are essential aboard ships where fresh water consumption can be over 30 tonnes per day. There are two main methods - distillation and reverse osmosis. Distillation involves boiling sea water under vacuum to evaporate it, then condensing the vapor to produce fresh water. Reverse osmosis uses semipermeable membranes to filter out salt and other ions. Fresh water generators recover waste heat from sources like the main engine to economically produce fresh water as needed.
1. The document discusses separation techniques for removing impurities from fuels, including gravity separation and centrifugation.
2. Gravity separation uses settling tanks and centrifuges apply centrifugal force to separate denser components like water and dirt from lighter components like fuel.
3. Centrifugation, or the use of centrifuges, amplifies the effects of gravity through high-speed rotation, allowing for more rapid and continuous separation than gravity alone.
The document provides guidelines for maintaining a fresh water generator (FWG) on a vessel:
1. Check the salinity alarm monthly to ensure only fresh water enters the fresh water tank.
2. Stop the FWG when approaching contaminated waters to prevent bacterial infection.
3. Open the separator shell and inspect for scale during scheduled maintenance or if production drops.
4. Clean the heating tubes twice a year or when production drops to prevent scale buildup.
The stern tube is a hollow tube running through the bottom of a ship that contains the propeller shaft. It connects the main engine to the propeller and supports the large weight of the propeller. Stern tubes are designed to keep water from leaking into the ship while allowing the propeller shaft to rotate freely. They contain bearings lubricated with oil or water to reduce friction and prevent leakage between the stern tube and propeller shaft. Modern systems aim to improve lubrication and reduce contamination of lubricants with water for more efficient propulsion.
This document provides information about shipboard incinerators. It defines an incinerator as machinery used to burn various wastes generated on ships, such as oily rags and galley waste. It describes typical incinerator features like refractory lining and automatic controls. It provides details on normal incinerator operation procedures, the types of wastes that can be incinerated according to IMO regulations, and emission standards for type approval testing. The document also outlines safety requirements for incinerator design, operation, controls, and fire protection in waste storage spaces.
The document discusses the MARPOL regulations governing shipboard incinerators. MARPOL Annex VI regulates incinerator emissions. Incinerators installed after 2000 must be certified to meet the specifications in MEPC Resolution 76(40), have an operations manual, and be operated by trained crew according to the manual. The regulations prohibit burning certain waste and require minimum flue gas temperatures. Incinerators are used to dispose of waste oil, garbage, and sewage, and the document describes standard incinerator features and operating procedures.
The document discusses various marine engineering systems including valves, cooling systems, fire systems, bilge systems, and ballast systems. It provides detailed diagrams and explanations of different valve types like globe valves, gate valves, check valves, and relief valves. It also explains the components and operation of a central marine cooling system including sea water, high temperature, and low temperature circuits. Furthermore, it outlines SOLAS requirements for fixed fire systems, emergency fire pumps, and bilge pumping systems. Overall, the document serves as a reference for the key components, regulations, and functioning of important shipboard engineering systems.
1. The document discusses separation techniques for removing impurities from fuels, including gravity separation and centrifugation.
2. Gravity separation uses settling tanks and centrifuges apply centrifugal force to separate denser components like water and dirt from lighter components like fuel.
3. Centrifugation, or the use of centrifuges, amplifies the effects of gravity through high-speed rotation, allowing for more rapid and continuous separation than gravity alone.
The document provides guidelines for maintaining a fresh water generator (FWG) on a vessel:
1. Check the salinity alarm monthly to ensure only fresh water enters the fresh water tank.
2. Stop the FWG when approaching contaminated waters to prevent bacterial infection.
3. Open the separator shell and inspect for scale during scheduled maintenance or if production drops.
4. Clean the heating tubes twice a year or when production drops to prevent scale buildup.
The stern tube is a hollow tube running through the bottom of a ship that contains the propeller shaft. It connects the main engine to the propeller and supports the large weight of the propeller. Stern tubes are designed to keep water from leaking into the ship while allowing the propeller shaft to rotate freely. They contain bearings lubricated with oil or water to reduce friction and prevent leakage between the stern tube and propeller shaft. Modern systems aim to improve lubrication and reduce contamination of lubricants with water for more efficient propulsion.
This document provides information about shipboard incinerators. It defines an incinerator as machinery used to burn various wastes generated on ships, such as oily rags and galley waste. It describes typical incinerator features like refractory lining and automatic controls. It provides details on normal incinerator operation procedures, the types of wastes that can be incinerated according to IMO regulations, and emission standards for type approval testing. The document also outlines safety requirements for incinerator design, operation, controls, and fire protection in waste storage spaces.
The document discusses the MARPOL regulations governing shipboard incinerators. MARPOL Annex VI regulates incinerator emissions. Incinerators installed after 2000 must be certified to meet the specifications in MEPC Resolution 76(40), have an operations manual, and be operated by trained crew according to the manual. The regulations prohibit burning certain waste and require minimum flue gas temperatures. Incinerators are used to dispose of waste oil, garbage, and sewage, and the document describes standard incinerator features and operating procedures.
The document discusses various marine engineering systems including valves, cooling systems, fire systems, bilge systems, and ballast systems. It provides detailed diagrams and explanations of different valve types like globe valves, gate valves, check valves, and relief valves. It also explains the components and operation of a central marine cooling system including sea water, high temperature, and low temperature circuits. Furthermore, it outlines SOLAS requirements for fixed fire systems, emergency fire pumps, and bilge pumping systems. Overall, the document serves as a reference for the key components, regulations, and functioning of important shipboard engineering systems.
The document discusses various piping systems on ships including bilge, ballast, air/sounding, firefighting, fuel oil, lubricating oil, cooling water, compressed air, domestic water, steam, and cargo systems. Key details provided include requirements for pump capacities, pipe sizing formulas, tank arrangements, safety features such as quick closing valves and alarms, and material considerations for high pressure/temperature applications.
Ship refrigeration plants play a vital role in transporting perishable cargo by maintaining the appropriate temperatures. The main components of refrigeration plants include compressors, condensers, receivers, driers, expansion valves, evaporators, and control units. Refrigeration plants use the vapor compression cycle to remove heat from cargo holds or crew areas, circulating a refrigerant through the components to absorb, compress, condense, expand, and evaporate heat.
The document discusses heat exchangers used on ships. It describes that heat exchangers transfer heat from one medium to another through direct contact or a separating wall. Common applications on ships include cooling lubricating oil and fresh water using sea water, and heating fuel oil using steam. The two main types are shell and tube exchangers, where one medium flows inside tubes and the other outside the tubes, and plate exchangers, where media flow on either side of corrugated plates. Proper design and maintenance are important for heat exchanger effectiveness and service life.
The document discusses various boiler mountings, which are crucial components that allow boilers to operate safely. It describes key mountings like safety valves, water level indicators, pressure gauges, and their functions. Safety valves in particular are discussed in depth, including their construction, types, setting pressures, testing procedures, and regulations. Maintaining proper boiler mountings is important for safety and optimal boiler performance.
The document describes the piping systems on a ship. It discusses the importance of an efficient piping system and provides examples of common piping systems like bilge, ballast, fuel, cooling water, lubrication oil, compressed air, steam, and cargo tank systems. It emphasizes preparing accurate piping plans and diagrams using standardized symbols and labeling key details like pipe sizes, flow directions, and component capacities. Common arrangements for pumping, drainage, overflows, and other aspects of key systems are illustrated with diagrams.
A boiler is a closed container that heats water or other fluids, which are then used for processes, heating applications, or to produce steam. Boilers come in two main types - fire tube boilers where hot gases pass through tubes surrounded by water, and water tube boilers where water passes through tubes surrounded by hot gases. Boilers have internal parts, valves, gauges, and mountings like safety valves, water level indicators, and drain valves that are directly related to pressure parts and boiler operation.
Auxiliary marine machinery systems are essential for proper ship functioning. They include pumps, compressors, and blowers for fuel, water, and air systems. They also include separators, steering machinery, winches, cranes and other deck equipment. The machinery space houses these systems and its size depends on the equipment installed. Common auxiliary equipment includes engines, steering gear, deck machinery, blocks, pulleys, pumps, masts, derricks, rollers, gantries, and various types of winches used for specific fishing methods and vessel operations. Proper maintenance of critical components like engines is important for auxiliary system reliability.
Fresh water generators are machines that convert salt water into fresh water for use on ships. They are an important system as ships need large quantities of fresh water for crew and passengers over long voyages. The generators work by evaporating sea water using heat, usually from the diesel engine jacket, which separates the pure water from salt and other elements. The main components are filters to remove impurities, a heat exchanger to evaporate the water and another to condense it back to liquid, and a salinometer to monitor salt content of the distilled water. Fresh water generators are crucial onboard systems that produce the daily fresh water needs of 30 tonnes for domestic uses and engine cooling.
Pumps are machines that use energy to move liquids from areas of low pressure to high pressure or from low to high levels. They work by reducing or increasing the volume of a space using reciprocating or rotary mechanisms. Common positive displacement pump types include reciprocating pumps, which use pistons, diaphragm pumps, and screw pumps. Screw pumps use meshing worm wheels to move liquid through central intake and discharge manifolds.
The document summarizes the machinery arrangement in a ship's engine room. It describes that the engine room contains main machineries that provide propulsion and auxiliary machineries that support operations with electrical power, cooling, and heating. Major machineries are categorized as critical because if they become inoperable, they can endanger ship operations. The document then lists and describes various main and auxiliary machinery located in the engine room, including the main engine, diesel generators, pumps, heat exchangers, refrigeration systems, and electrical equipment. It also lists storage tanks located in the engine room for liquids like fuels, oils, and water.
The document discusses various types of deck machinery and equipment used on ships, including:
- Windlasses and mooring winches used for anchoring and mooring.
- Hatch cover openers, winches, derricks, and cranes used for cargo handling.
- Pumps and other equipment used on specialized ship types like LNG carriers.
- Components and operation of typical anchoring systems including the anchor, chain, and windlass.
- Electric, hydraulic, and other drive systems used to power deck machinery.
- Cargo winches and derrick/crane systems and their use in cargo handling.
- Types of hatch covers including hydraulic folding and rolling varieties.
This document discusses ship maneuvering systems including rudders, propellers, and steering gears. It describes different types of rudders such as balanced, semi-balanced, and unbalanced rudders. It also discusses factors that affect rudder design and placement including ship size and maneuverability requirements. Additionally, it covers active rudder systems like azimuth thrusters and Voith Schneider propellers that can provide thrust in any direction for improved maneuverability.
The cylinder liner forms the cylindrical space in the engine where the piston reciprocates. It is manufactured separately from the cylinder block using an alloy that has better wear resistance at high temperatures. This allows for replacement of just the liner if it wears. The liner is cooled, often with tangential bore cooling, to maintain an optimal temperature for lubrication and reducing thermal stresses. Proper lubrication and minimizing abrasive particles are important to reduce liner wear over the life of the engine.
The document discusses regulations regarding the treatment and discharge of sewage from ships as outlined in MARPOL Annex IV. It provides details on definitions of sewage, typical sewage generation amounts, treatment methods including mechanical, chemical and biological, and standards for effluent quality and discharge distances. Requirements include having an approved sewage treatment plant and International Sewage Pollution Prevention Certificate when discharging in special areas like the Baltic Sea.
Types, Operations and Maintenance of Air Compressor PlantsNejat Öztezcan
The document discusses maintenance and operation of air compressor plants. It provides information on different types of compressors used on ships, including:
1. Main air compressors which provide high-capacity air storage for starting engines.
2. Deck compressors which are smaller and more portable for tasks like pneumatic tools.
3. Emergency compressors which serve as a backup air source in emergencies to start auxiliary engines if the main compressor fails.
The document outlines compressor systems, components, efficiency factors, and procedures for checking bumping clearance on main air compressors.
The document discusses various marine propulsion systems. It describes how ships are typically powered through a propeller connected to an engine that transforms an energy source into mechanical power. Common energy sources discussed include fossil fuels like diesel powering most ships, as well as alternative sources like solar, wind, nuclear, hydrogen, and wave energy being explored. The document also examines different types of engines like steam, diesel, gas turbine, and their use in marine propulsion applications.
The document discusses the cooling system used for marine diesel engines. Fresh water is circulated through the engine to absorb heat and is then cooled via a seawater system. The fresh water is treated to prevent corrosion and scale buildup. A header tank maintains system pressure and monitors for leaks. Some ships use a central cooling system to keep alternate engines warm and ready to start.
The document discusses various piping systems on ships including bilge, ballast, air/sounding, firefighting, fuel oil, lubricating oil, cooling water, compressed air, domestic water, steam, and cargo systems. Key details provided include requirements for pump capacities, pipe sizing formulas, tank arrangements, safety features such as quick closing valves and alarms, and material considerations for high pressure/temperature applications.
Ship refrigeration plants play a vital role in transporting perishable cargo by maintaining the appropriate temperatures. The main components of refrigeration plants include compressors, condensers, receivers, driers, expansion valves, evaporators, and control units. Refrigeration plants use the vapor compression cycle to remove heat from cargo holds or crew areas, circulating a refrigerant through the components to absorb, compress, condense, expand, and evaporate heat.
The document discusses heat exchangers used on ships. It describes that heat exchangers transfer heat from one medium to another through direct contact or a separating wall. Common applications on ships include cooling lubricating oil and fresh water using sea water, and heating fuel oil using steam. The two main types are shell and tube exchangers, where one medium flows inside tubes and the other outside the tubes, and plate exchangers, where media flow on either side of corrugated plates. Proper design and maintenance are important for heat exchanger effectiveness and service life.
The document discusses various boiler mountings, which are crucial components that allow boilers to operate safely. It describes key mountings like safety valves, water level indicators, pressure gauges, and their functions. Safety valves in particular are discussed in depth, including their construction, types, setting pressures, testing procedures, and regulations. Maintaining proper boiler mountings is important for safety and optimal boiler performance.
The document describes the piping systems on a ship. It discusses the importance of an efficient piping system and provides examples of common piping systems like bilge, ballast, fuel, cooling water, lubrication oil, compressed air, steam, and cargo tank systems. It emphasizes preparing accurate piping plans and diagrams using standardized symbols and labeling key details like pipe sizes, flow directions, and component capacities. Common arrangements for pumping, drainage, overflows, and other aspects of key systems are illustrated with diagrams.
A boiler is a closed container that heats water or other fluids, which are then used for processes, heating applications, or to produce steam. Boilers come in two main types - fire tube boilers where hot gases pass through tubes surrounded by water, and water tube boilers where water passes through tubes surrounded by hot gases. Boilers have internal parts, valves, gauges, and mountings like safety valves, water level indicators, and drain valves that are directly related to pressure parts and boiler operation.
Auxiliary marine machinery systems are essential for proper ship functioning. They include pumps, compressors, and blowers for fuel, water, and air systems. They also include separators, steering machinery, winches, cranes and other deck equipment. The machinery space houses these systems and its size depends on the equipment installed. Common auxiliary equipment includes engines, steering gear, deck machinery, blocks, pulleys, pumps, masts, derricks, rollers, gantries, and various types of winches used for specific fishing methods and vessel operations. Proper maintenance of critical components like engines is important for auxiliary system reliability.
Fresh water generators are machines that convert salt water into fresh water for use on ships. They are an important system as ships need large quantities of fresh water for crew and passengers over long voyages. The generators work by evaporating sea water using heat, usually from the diesel engine jacket, which separates the pure water from salt and other elements. The main components are filters to remove impurities, a heat exchanger to evaporate the water and another to condense it back to liquid, and a salinometer to monitor salt content of the distilled water. Fresh water generators are crucial onboard systems that produce the daily fresh water needs of 30 tonnes for domestic uses and engine cooling.
Pumps are machines that use energy to move liquids from areas of low pressure to high pressure or from low to high levels. They work by reducing or increasing the volume of a space using reciprocating or rotary mechanisms. Common positive displacement pump types include reciprocating pumps, which use pistons, diaphragm pumps, and screw pumps. Screw pumps use meshing worm wheels to move liquid through central intake and discharge manifolds.
The document summarizes the machinery arrangement in a ship's engine room. It describes that the engine room contains main machineries that provide propulsion and auxiliary machineries that support operations with electrical power, cooling, and heating. Major machineries are categorized as critical because if they become inoperable, they can endanger ship operations. The document then lists and describes various main and auxiliary machinery located in the engine room, including the main engine, diesel generators, pumps, heat exchangers, refrigeration systems, and electrical equipment. It also lists storage tanks located in the engine room for liquids like fuels, oils, and water.
The document discusses various types of deck machinery and equipment used on ships, including:
- Windlasses and mooring winches used for anchoring and mooring.
- Hatch cover openers, winches, derricks, and cranes used for cargo handling.
- Pumps and other equipment used on specialized ship types like LNG carriers.
- Components and operation of typical anchoring systems including the anchor, chain, and windlass.
- Electric, hydraulic, and other drive systems used to power deck machinery.
- Cargo winches and derrick/crane systems and their use in cargo handling.
- Types of hatch covers including hydraulic folding and rolling varieties.
This document discusses ship maneuvering systems including rudders, propellers, and steering gears. It describes different types of rudders such as balanced, semi-balanced, and unbalanced rudders. It also discusses factors that affect rudder design and placement including ship size and maneuverability requirements. Additionally, it covers active rudder systems like azimuth thrusters and Voith Schneider propellers that can provide thrust in any direction for improved maneuverability.
The cylinder liner forms the cylindrical space in the engine where the piston reciprocates. It is manufactured separately from the cylinder block using an alloy that has better wear resistance at high temperatures. This allows for replacement of just the liner if it wears. The liner is cooled, often with tangential bore cooling, to maintain an optimal temperature for lubrication and reducing thermal stresses. Proper lubrication and minimizing abrasive particles are important to reduce liner wear over the life of the engine.
The document discusses regulations regarding the treatment and discharge of sewage from ships as outlined in MARPOL Annex IV. It provides details on definitions of sewage, typical sewage generation amounts, treatment methods including mechanical, chemical and biological, and standards for effluent quality and discharge distances. Requirements include having an approved sewage treatment plant and International Sewage Pollution Prevention Certificate when discharging in special areas like the Baltic Sea.
Types, Operations and Maintenance of Air Compressor PlantsNejat Öztezcan
The document discusses maintenance and operation of air compressor plants. It provides information on different types of compressors used on ships, including:
1. Main air compressors which provide high-capacity air storage for starting engines.
2. Deck compressors which are smaller and more portable for tasks like pneumatic tools.
3. Emergency compressors which serve as a backup air source in emergencies to start auxiliary engines if the main compressor fails.
The document outlines compressor systems, components, efficiency factors, and procedures for checking bumping clearance on main air compressors.
The document discusses various marine propulsion systems. It describes how ships are typically powered through a propeller connected to an engine that transforms an energy source into mechanical power. Common energy sources discussed include fossil fuels like diesel powering most ships, as well as alternative sources like solar, wind, nuclear, hydrogen, and wave energy being explored. The document also examines different types of engines like steam, diesel, gas turbine, and their use in marine propulsion applications.
The document discusses the cooling system used for marine diesel engines. Fresh water is circulated through the engine to absorb heat and is then cooled via a seawater system. The fresh water is treated to prevent corrosion and scale buildup. A header tank maintains system pressure and monitors for leaks. Some ships use a central cooling system to keep alternate engines warm and ready to start.
An ice plant uses a refrigeration system similar to a simple vapor-compression refrigeration system. It contains major components like a compressor, condenser, expansion valve, evaporator and chilling tank. Water is frozen into blocks of ice in cans placed inside the chilling tank, which is filled with a brine solution maintained at -10°C by the refrigeration system. It takes 24-48 hours to freeze 150-300lb blocks of ice. The frozen ice blocks are then removed from the cans and stored or delivered. Ice plants play an important role in preserving foods, chemicals and providing cooling for various industrial processes.
This document discusses Ocean Thermal Energy Conversion (OTEC) technologies. OTEC uses the temperature difference between warm surface seawater and cold deep seawater to produce electricity. There are three main types of OTEC systems - open cycle, closed cycle, and hybrid cycle. OTEC has advantages such as steady base load power production and byproducts like fresh water. However, it also has disadvantages like low efficiency due to small temperature differences and challenges associated with operating in an ocean environment. The document provides examples of OTEC applications and references for further information.
Ocean Thermal Energy Conversion (OTEC) utilizes the temperature difference between warm surface seawater and cold deep seawater to produce electricity via a Rankine cycle. OTEC systems can generate electricity, desalinate water, support aquaculture, and provide refrigeration. While OTEC is a promising renewable energy source that does not emit carbon, its high capital costs and untested commercial scale have prevented widespread adoption.
1. Ocean thermal energy conversion (OTEC) is a process that generates electricity using the temperature difference between warm surface ocean water and cold deep sea water.
2. OTEC utilizes this temperature difference to power a turbine and generate electricity via a closed-loop or open-loop system. In a closed-loop system, warm water heats a fluid that powers a turbine, while in an open-loop system the warm water itself powers the turbine.
3. OTEC has potential applications for electricity generation, desalination, refrigeration, and mineral extraction. It is a renewable source of energy but high capital costs have prevented widespread commercial use.
This document discusses steam generators and feedwater heaters used in thermal and nuclear power plants. It provides definitions of boilers and steam generators, describing their main components like drums, superheaters, and economizers. It compares firetube and watertube boilers, listing advantages and disadvantages of each. The document also describes types of feedwater heaters like open and closed, and their purposes in preheating feedwater to improve thermodynamic efficiency.
This document summarizes the details of two unused stainless steel evaporative condensers. Each unit is rated at 827 tons and was manufactured by Evapco with model ATW-207C. The units feature stainless steel construction, enclosed fan motors, quick connect piping, sloped access ladders, and elliptical coil designs. Additional details are provided on optional accessories and each unit's dimensions and electrical specifications.
Vortex tube refrigeration uses compressed air and has no moving parts. Air is passed through a nozzle into a chamber where it spins creating hot and cold streams. The cold air exits through a diaphragm hole while the hot air exits through a valve. Steam jet refrigeration uses steam expanded through nozzles to lower pressure and boil water below 100C for refrigeration. High pressure steam enters nozzles and flash chamber, lowering pressure and evaporating water to decrease temperature before chilled water is circulated for use. Both systems have advantages of simplicity and flexibility but limited capacity and efficiency.
STEAM JET COOLING SYSTEM
Steam jet cooling system is a cooling technique which involves usage of steam and water for cooling purposes. In steam jet refrigeration systems, water can be used as the refrigerant. Like air, it is perfectly safe. These systems were applied successfully to refrigeration.
•Temperatures attained using water as a refrigerant are in the range which may satisfy air conditioning, cooling, or chilling requirements.
•Mostly low-grade energy and relatively small amounts of shaft work.
•This system are the utilization of mostly low-grade energy and relatively small amounts of shaft work.
•Not used when temperatures below 5°C are required.
Pharma Mfg BASICS for new learners useful informationraviralagiri02
Unit processes involve chemical changes through chemical reactions, while unit operations involve physical changes without chemical reactions. Common unit operations include separation, size reduction, heating and cooling. A batch process involves intermittent operation where materials are added and removed at different stages, while a continuous process operates continuously with constant feeding and removal of materials. Safety measures for working with reactors include proper earthing, not overfilling reactors, not exceeding agitator speed limits, and preventing sparks.
Körting steam jet chilling plants use water as a refrigerant and provide environmentally-friendly operation with high operational safety and minimal maintenance needs. They utilize unused steam to power a jet vacuum ejector that cools liquid through flash evaporation without mechanical components. Applications include large chilling capacities over 1 MW for processes with excess steam. Multi-stage designs further reduce steam and water usage to lower costs.
Körting steam jet chilling plants use water as a refrigerant and provide environmentally-friendly operation with high operational safety and minimal maintenance needs. They utilize unused steam to power a jet vacuum ejector that cools liquid through flash evaporation without mechanical components. Applications include large chilling capacities over 1 MW for processes with excess steam. Multi-stage designs further reduce steam and water usage to lower costs.
Ocean Thermal Energy Conversion (OTEC) utilizes the temperature difference between warm surface seawater and cold deep seawater to operate a heat engine and produce electricity via a closed-cycle system. OTEC systems pump warm surface water through an evaporator which powers a turbine, while nearly freezing water from 1000 meters below is used to condense the working fluid in a condenser. In addition to power generation, OTEC can support desalination, mariculture, refrigeration, and chemical production. The vast solar energy stored in tropical ocean temperature differences has potential to provide clean electricity while promoting fisheries and producing fresh water.
The document discusses various technologies for reducing emissions from ship engines, including those that reduce NOx and SOx emissions. It discusses methods such as humid air injection, exhaust gas recirculation, water injection, and selective catalytic reduction to reduce NOx. It discusses using low-sulfur fuels and exhaust gas scrubbers to reduce SOx. It also discusses liquefied natural gas carriers and technologies for reliquefying boil-off gas, including multi-stage compression and closed-loop nitrogen cycles to efficiently re-liquefy gas.
Ocean Thermal Energy Conversion (OTEC) utilizes the temperature difference between warm surface seawater and cold deep seawater to produce electricity via a heat engine. OTEC can also be used to generate desalinated water, support aquaculture, and provide refrigeration. While OTEC has potential benefits like being carbon-free, challenges include high capital costs and lack of demonstration at full commercial scale.
Fabrication of 2 way cross flow cooling tower for high pressure boilerEcway Technologies
This document describes the fabrication of a 2-way cross flow cooling tower for a high pressure boiler. It discusses cooling towers which use evaporation or air to remove process heat and cool working fluids. The objective is to remove heat from industrial sources like machinery using large cooling towers, as seen in power plants. It explains that a cooling tower allows dissipating heat into the atmosphere instead of discharging hot water into local bodies of water, which can harm ecosystems. It then provides details on the working principle of a cross flow design where air and water flow perpendicularly through a fill material for efficient heat transfer.
This document describes the fabrication of a 2-way cross flow cooling tower for a high pressure boiler. It discusses cooling towers which use evaporation or air to remove process heat and cool working fluids. The objective is to remove heat from industrial sources like machinery using large cooling towers, as seen in power plants. It explains that a cooling tower allows dissipating heat into the atmosphere instead of discharging hot water into local bodies of water, which can harm ecosystems. It then provides details on the working principle of a cross flow design where air and water flow perpendicularly through a fill material for efficient heat transfer.
This document describes the fabrication of a 2-way cross flow cooling tower for a high pressure boiler. It discusses cooling towers' use in removing waste heat from industrial processes like power plants and transferring it to the atmosphere. The objective is to cool circulating water more efficiently than once-through systems. It explains that a cross flow design directs air and water perpendicular to each other through fill material for efficient heat transfer, while conserving more water than once-through systems.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Training: ISO/IEC 27001 Information Security Management System - EN | PECB
ISO/IEC 42001 Artificial Intelligence Management System - EN | PECB
General Data Protection Regulation (GDPR) - Training Courses - EN | PECB
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How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
2. Fresh water production from sea water for domestic and auxiliary
purposes is an essential requirement aboard ships.
A considerable amount of fresh water is consumed in a ship.
The crew consumes an average 100 liter/head/day. In a steam ship (a
ship whose main propulsion unit is steam turbine or a ship which is a
large tanker having steam turbine driven cargo oil pumps) the
consumption for the boiler can be as high as 30 tonnes/day.
Sufficient potable water may be taken on in port to meet crew and
passenger requirement. But the quality of this water will be too poor for
use in water tube boilers and for filling expansion tanks.
It is common practice to take on only a minimum supply of potable
water and make up the rest by distillation of sea water.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
3. The stowage space that would have been used for fresh water can
hence be utilized for fuel or extra space made available for cargo when
fresh water generator is installed on a ship.
The equipment used on board for the production of freshwater from
seawater is known as fresh water generator.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
4. There are two methods for generating fresh water:
• Distillation
• Reverse Osmosis (RO)
Distillation is a process in which impure water is boiled and the steam is
collected and condensed in a separate container, leaving many of the
solid contaminants behind.
Reverse osmosis (RO) desalination is a method of producing fresh water
from seawater by a process similar to filtration, rather than by
traditional evaporative distillation. A semipermeable membrane allows
water molecules to pass through while blocking the passage of most
other ions.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
5. Distillation is cheaper and effective for less quantity but RO is costly and
for large quantity production. RO is used on Passenger ship where large
quantity of water is consumed.
Distillation = (Evaporation + Condensation)
Reverse Osmosis = (Semi permeable membrane - filter)
What ever type of plant is used, essential requirement of any fresh
water generator is that it should produce fresh water as economically as
possible.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
6. Distillation process (method) is widely used on merchant ships.
Distillation is the combination of 2 process, evaporation and
condensation.
Evaporation can be done in 2 ways :
Evaporation by Boiling
Evaporation by Flash
Distillation can be done by 2 ways - Boiling or Flash.
Boiling and distillation process, on the basis of condenser's
structure it is divided into 2 following types :
(1) Tube type
(2) Plate type. Hüseyin Nejat ÖZTEZCAN Chief Engineer
9. What ever type of plant is used, essential requirement of any fresh
water generator is that it should produce fresh water as economically as
possible..
Even with a very efficient engine, only about 50% of the heat in the fuel
is converted into useful work at the crankshaft. The remainder
potentially wasted.
Main engine jacket cooling water also contains a considerable quantity
of heat this may be recovered in fresh water evaporators.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
11. A desalination plant (also known as a fresh water generator)
onboard a floating structure is quite different from a land-based
desalination plant.
It operates in a very corrosive environment .
Rolling and pitching of the ship is also taken into consideration while
designing the desalination plant.
To avoid cavitation problems, an adequate quantity of water at
required pressure is always made available at a pump suction.
The vapours which are condensed on the condenser tubes are
collected in a product water sump. A sloping product water sump
may be provided depending on the extent of rolling to enable the
product water pump suction to be always full of liquid and avoid
cavitation problems or dry running of the pump.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
12. Materials of Construction for Fresh Water Generator :
The shell is usually fabricated steel (or non-ferrous metal like
cupro-nickels) which has been shot blasted then coated with
some form of protective.
The important points about protective coatings are:
•They must be inert and prevent corrosion.
•They must resist the effect of acid cleaning and water
treatment chemicals
•They must have a good bond with the metal
Hüseyin Nejat ÖZTEZCAN Chief Engineer
13. Heat exchangers use aluminium brass tubes and muntz netal
tube plate (60/40 copper alloyed with zinc) in the case of tube
type fresh water generator.
For plate type, titanium plates are used for condenser and
evaporator. Demister is made of layered knitted wire of monel
metal.
A distilling plant be capable of operating for at least 90 days at
rated capacity without shutdown for cleaning.
Maritime Administration specifications require that "each
desalination unit be capable of unattended automatic operation
after being put on the line locally."
Hüseyin Nejat ÖZTEZCAN Chief Engineer
14. Boiling Process :
Sea Water is boiled in the evaporator at saturation temperature,
corresponding to the pressure in the evaporator.
Sea Water is kept at saturation temperature always.
It is of 2 types
If evaporator is plate type then it is called Plate type fresh water
generator
and If tubes are used for heating then it is called Tube type fresh
water generator. Also called submerged type, because heating
coils are submerged.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
17. Advantages and Disadvantages of Shell and Tube and Plate type Heat
Exchangers
A . Plate Type Heat Exchangers
Advantages
• Simple and Compact in size
• Heat transfer efficiency is more
• Can be easily cleaned
• No extra space is required for dismantling
• Capacity can be increased by introducing plates in pairs
• Leaking plates can be removed in pairs, if necessary without
replacement
• Maintenance is simple
• Turbulent flow help to reduce deposits which would interfere with
heat transfer
Hüseyin Nejat ÖZTEZCAN Chief Engineer
18. Disadvantages
• Initial cost is high since Titanium plates are expensive
• Finding leakage is difficult since pressure test is not as easy as tube
coolers
• Bonding material between plates limits operating temperature of
the cooler
• Pressure drop caused by plate cooler is higher than tube cooler
• Careful dismantling and assembling to be done
• Over tightening of the clamping bolts result in increased pressure
drop across the cooler
• Joints may be deteriorated according to the operating conditions
• Since Titanium is a noble metal, other parts of the cooling system
are susceptible to corrosion
Hüseyin Nejat ÖZTEZCAN Chief Engineer
19. B. Shell and Tube Heat Exchangers
Advantages
• Less expensive as compared to Plate type coolers
• Can be used in systems with higher operating temperatures and pressures
• Pressure drop across a tube cooler is less
• Tube leaks are easily located and plugged since pressure test is
comparatively easy
• Using sacrificial anodes protects the whole cooling system against corrosion
Disadvantages
• Heat transfer efficiency is less compared to plate type cooler
• Cleaning and maintenance is difficult since a tube cooler requires enough
clearance at one end to remove the tube nest
• Capacity of tube cooler cannot be increased.
• Requires more space in comparison to plate coolers
Hüseyin Nejat ÖZTEZCAN Chief Engineer
20. Fresh Water Generator Working Principle:
Water is generally produced on board using the distilation method.
•Fresh water is produced by evaporating sea water using heat from
any of the heat source.
•The evaporated sea water is then again cooled by the sea water
and the cycle repeats.
•Generally the heat source available is taken from the main engine
jacket water, which is used for cooling the main engine components
such as cylinder head, liner etc.
•The temperature available from this jacket water is about 80°C
Hüseyin Nejat ÖZTEZCAN Chief Engineer
21. •But at this temperature the evaporation of water is not possible as
we all know that the evaporation of water takes place at 100°C
under atmospheric pressure.
•Thus in order to produce fresh water at 80°C, we need to reduce
the atmospheric pressure, which is done by creating a vacuum
inside the chamber where the evaporation is taking place.
•Also, as a result of the vacuum the cooling of the evaporated sea
water will also take place at lower temperature.
•This cooled water is collected and transferred to the tank.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
22. Boiling
Point
Pressure Boiling Point Pressure
°C atm °C atm
5 0,0085 55 0,1553
10 0,0120 60 0,1965
15 0,0167 65 0,2468
20 0,0229 70 0,3075
25 0,0311 75 0,3804
30 0,0418 80 0,4674
35 0,0554 85 0,5704
40 0,0727 90 0,6919
45 0,0945 95 0,8342
50 0,1216 100 1,0000
WATER – PRESSURE AND BOILING POINTS
Hüseyin Nejat ÖZTEZCAN Chief Engineer
25. How we create a vacuum in fresh water generators ?
Vacuum is created using a device called “Air Ejector”
An air ejector is a device which uses the motion of moving fluid
(Motive Fluid) to transport another fluid (Suction fluid). It is has a
wide range of application in steam ejector in boiler condenser, fresh
water generator and in priming the centrifugal pump.
Ejector Pump
The ejector pump supplies seawater to the ejectors and also to the
heat exchanger.
The seawater goes to the ejectors in order to create a vacuum in the
boiling section.
This vacuum serves to lower the boiling point of the water, and to
allow the brine from the desalinated water to be returned to the
sea. Hüseyin Nejat ÖZTEZCAN Chief Engineer
26. An air ejector which uses the high pressure motive fluid such as sea
water to flow through the nozzle. The function of the nozzle is to
convert the pressure energy of the motive fluid into the velocity
energy.
P1-pressure of the fluid entering the nozzle.
V1- velocity of the fluid entering the nozzle.
P2- pressure of the fluid leaving the nozzle.
V2- velocity of the fluid leaving the nozzle.
By Bernoulli’s theorem:
P1 × V1 = P2 × V2.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
28. This diagram shows the basic components of an Ejector used in the
Fresh Water Generators.
This Ejector was designed for use with sea water.
These are:
1) There are three connections. One for the high pressure sea water
(ejector pump discharge), one for the low pressure (LP) suction
entrained and one for the medium pressure discharge.
2) The suction (in this case air or brine) comes in at the side.
3) There is a nozzle for converting the pressure energy of the high
pressure motive into kinetic energy.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
29. REGULATIONS REGARDING PRUDUCTION OF SEA
WATER ON BOARD SHIP
• Cannot be used in ports, anchorages and closer to shore than
12 nm because of domestic sewage and industrial effluents.
• Engine must be running at full ahead sea speed during start of
FWG
• Ensure main engine parameters are normal
• Shipo is not maneuvering
• There is no oil/chemical reported in the visinity of the ship
• Unfit as potable water because:
- Not sterilised
- Tasteless
- Slightly acidic in nature
- Devoid of any minerals requried for human body.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
30. SHELL AND TUBE TYPES FRESH WATER
GENERATORS (SASAKURA)
Hüseyin Nejat ÖZTEZCAN Chief Engineer
35. OPERATION PRINCIPLES
• The Evaporator Chamber is kept under vacuum by a Water Ejector.
Sea water supplied by Ejector Pump drives Water Ejector, and
enters into the Tubes of Condenser as a cooling medium, then is
discharged overboard.
• Parts of the jacket cooling water (fresh water) circulates to the
outside of the heater tubes giving up some of its heat to the sea
water which flows inside the tubes.
• The heated sea water (feed water) evaporates as it enters the main
chamber due to the vacuum condition. Water droplets are removed
from the vapor by the deflector and mesh separator. The seperated
droplets fall back into the brine, which is extracted from the
chamber and discharged overboard.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
36. • The vapor passes to the condenser tube bundle which is cooled by
sea water flowing inside the tubes. The condensed vapor is
collected and pumped to the fresh water storage tank by the
distillate pump.
• The sea water used in the condenser becomes warmed up as the
vapor gives up its heat of condensation. Part of this warm sea
water is used as the feed water to the FWG.
• The salinity of the distllate is monitored by a conductivity dedector.
If the salinity exceeds the specific level, the selenoid valve in the
discharge line of the distillate pump is automatically activated and
the faulty distillate is returned to the brine side of the evaporation
chamber.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
37. FRESH WATER GENERATORS MAIN COMPONENTS AND FUNCTIONS
• The main body of a fresh water generator on the ship consists of a
large cylindrical body with two compartments. One of the
compartments is the condenser and the other is the evaporator.
• Condenser: It exchanges the latent heat ın the produced fresh
vapours to the cooling water so that the vapours are condensed
and accumulated ın the bottom of the condenser ‘s shell.
• Evaporator: It is used to boil off the seawater at lower temperature
with the help of vacuum created inside Fresh Water Generator
shell.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
38. • An Air Ejector: To Create Vacuum In the main body.
• A Brine Ejector: The brine ejector removing brine and salt
deposits from the evaporator chamber.
• Combined brine and air ejector: The combined brine and air
ejector extracts brine and incondensable gases from the
separator vessel.
• A Sea Water Ejector Pump: For supplying necessary sea water
required for production of fresh water .
• A Fresh Water Distillate Pump: For pumping the f/w produced
from condensor chamber into f/w storage tank.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
39. • A Salinometer: For measuring the ppm of Fresh Water produced
which is generally 1-10 ppm. If more than 10 ppm (as set by
operater), an alarm sounds and The Fresh Water produced is
bypassed back to the evaporater.
• Demister: The water vapour pass through the demister which will
remove the carried salt and only allow the water vapour to pass
through.
• Vacuum Breaker Valve: For releasing the vacuum at the time of
shutting down.
• Flow Meter: The flow meter ındicates the accumulated fresh water
produced.
• Relief Valve: For releasing the excess pressure.
• Control panel: Contains motor starters with thermal overload relays
and running lights for each pump, salinometer and alarm panel.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
40. SALINOMETER
• Pure distilled water may be considered a non-conductor of
electricity. The addition of impurities such as salts in solution
increases the conductivity of the water, and this can be measured.
Since the conductivity of the water is, for low concentrations,
related to the impurity content, a conductivity meter can be used
to monitor the salinity of the water.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
42. Starting the Fresh Water Generator
1. Before starting the fresh water generator we have to check that
the ship is not in congested water, canals and is 20 nautical miles
away from the shore. This is done because near the shore the
effluents from factories and sewage are discharged into the sea
can get into the fresh water generator.
2. Check whether engine is running above 50 rpm, the reason for
this is that at low rpm the temperature of jacket water which is
around 60 degrees and not sufficient for evaporation of water.
3. Check the drain valve present at the bottom of the generator is in
close position.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
43. 4. Now open suction and discharge valves of the sea water ejector
pump which will provide water for evaporation, cooling and to
the ejector for creating vacuum.
5. Open the sea water discharge valve from where the water is sent
back to the sea after circulating inside the fresh water generator.
6. Close the vacuum breaker valve situated on top of the generator.
7. Now start the sea water pump and check the pressure of the
pump. The pressure is generally 3-4 bars.
8. Wait for the vacuum to build up. Vacuum should be at least 90%
which can be seen on the gauge present on the generator.
Generally the time taken for the generation of vacuum is about
10 minutes. Hüseyin Nejat ÖZTEZCAN Chief Engineer
44. 9. When vacuum is achieved open the valve for feed water
treatment, this is to prevent scale formation inside the plates.
10. Now open hot water (jacket water) inlet and outlet valves slowly
to about half. Always open the outlet valve first and then inlet
valve. Slowly start to increase the opening of the valves to full
open.
11. Now we can see that the boiling temperature starts increasing and
the vacuum starts dropping.
12. The vacuum drop to about 85% which is an indication that
evaporation is started.
13. Open the valve from fresh water pump to drain.
14. Switch on the salinometer if it has to be started manually.
Generally it is on auto start.Hüseyin Nejat ÖZTEZCAN Chief Engineer
45. 15. Now start fresh water pump and taste the water coming out of the
drain.
16. When fresh water starts producing it is seen that the boiling
temperature drops again slightly and vacuum comes back to the
normal value.
17. Check the water coming out of the salinometer is not salty and also
check the reading of the salinometer. This is done to see if the
salinometer is working properly or not and to prevent the whole fresh
water from getting contaminated with salt water. The value of
salinometer is kept below 10ppm.
18. After checking the taste of the water coming out of the
salinometer, open valve for tank from the pump and close drain valve.
Note : The distillate water shall be disposed out for min. 30 minutes at
the initial start up of the distillate pump.Hüseyin Nejat ÖZTEZCAN Chief Engineer
46. REGULATING THE CAPACITY
The capacity (quantity of produced water) of the Fresh Water
Generator is regulated by increasing or decreasing the quantities of
Jacket cooling water to the heat exchanger. The capacity of the plant
is measured by means of the water meter.
The quantity of the Jacket cooling water shall be regulated by the
by-pass valve to the fresh water cooIer until the plant produces its
normaI capacity.
In case that the temperature of the jacket cooling water is lower
than the prescribed one, the flow quantity passing throught the
heat exchanger shall be increased more.
The supply of cooling sea water to the condenser is regulated so
that the cooling sea water temperature rises about prescribed value
when passing through the cooling tubes of the condenser.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
47. The evaporation temperature should be about 450C to 600 C.
Evaporation temp. may become much lower than suitable range
when ship sails in low sea water temp. area. In such case,
Evaporation temp. must be raised by means of either adjusting
"VACUUM ADJUST VALVE" on air extraction line, or reducing
condenser cooling sea water flow rate .
If the evaporation temperature is too high which may occur at high
cooling sea water temperature, the quantity of cooling sea water to
the condenser is increased which will make the evaporation
temperature drop.
Too high evaporation temperatures increase the risk of scale
formation in the tubes of the heat exchanger, and too low
evaporation temperature will owing to the resulting great vapour
volumes mean a risk that sea water drops air brought with to the
condenser resulting in fresh water with a too high salt content.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
48. Stopping the Fresh water Generator
1. Close the jacket water inlet valves. Generally inlet is closed first
and then the outlet valve.
2. Close the valve for feed water treatment.
3. Stop fresh water pump.
4. Switch off the salinometer.
5. Stop ejector pump.
6. Open vacuum breaker valve.
7. Close sea water suction valve and overboard valve. This is
generally not required as they are non- return valves.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
49. Precautions for Operation of Fresh water Generator :
1.Seawater pressure at the inlet of air ejector must be 3 bar or
more.
2.The pressure at ejector outlet should not exceed 0.8 bar.
3.Never start fresh water generator distillate pump in dry
condition.
4.Operate jacket cooling water valves to the fresh water
generator gradually to avoid thermal shock to the main engine.
5.Feed water to be supplied for a few minutes to cool down
the evaporator before stopping.
6.Never open the drain valve of evaporator before opening
vacuum breaker. Otherwise atmospheric pressure causesHüseyin Nejat ÖZTEZCAN Chief Engineer
50. MAİNTENANCE
Why you need to perform regular maintenance duties ?
Regular maintenance of the plant will improve performance and
availability.
The maintenance schedule will tell you how often service should be
performed on the main components. As the actual operating
conditions of the plant are of major influence on the life time, the
overhaul dates are not obligatory but only recommended intervals.
When the plant has been in operation for a longer period of time
and experience has been established as to the actual performance,
it will be possible to adapt the maintenance schedule.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
51. During the operation of evaporating plants, scale will form on the
heating surfaces. The rate of scale formation will depend upon the
operating temperature, the flow rate and density of the brine.
Scale formation will result in greater requirements for heating to
produce the rated quantities of distilled water or a fall-off in
production for a fixed heating supply.
Cold shocking, the alternate rapid heating and cooling of the tube
surfaces, for a boiling process type, can reduce scale build-up.
Ultimately, however, the plant must be shut down and the scale
removed either by chemical treatment or manual cleaning.
Also a routine maintenance of the generator should be carried out
by shutting down the plant and removing the scale manually or by
chemical treatments. Hüseyin Nejat ÖZTEZCAN Chief Engineer
52. The internal walls of the chamber or the shell should also be
cleaned when the overall cleaning is done.
Air ejectors and educators should also be checked for holes or
leakages, which can prevent the formation of desired vacuum.
The distiller, feed and brine pumps should also be properly
maintained to prevent any interruption in the flow of fresh and sea
water. The processes and the phenomena used in both plate and
tube type FWGs are the same.
A constant check should be kept on the flow meter to prevent
excessive or very less flow.
The salinometer alarm should be precisely set and given a constant
watch. This is to prevent the degrading of the quality of fresh water
produced.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
53. Maintenance of Plate surface :
Clean Plate surface as follows:
1. Remove tightening bolts
2. Open plate stack
3. Remove plate stack
4. Submerge plates completely in a hot, inhibited acid bath at
maximum 50ºC.
5. Scrub plates with a soft brush and plain hot water at maximum 50°C.
6. Examine plates and gaskets for possible damage, and remove
damaged plates and/ or replace damaged gaskets.
If a defective plate is found, remove the plate together with one of the
adjacent plates.
The end plate and start plate cannot be removed but must always be
replaced, with a corresponding plate.Hüseyin Nejat ÖZTEZCAN Chief Engineer
54. 7. Reassemble the plate stack in accordance with attached assembly
scheme.
8. Tighten plate stack to measurements stated in technical specification.
9. Vacuum test the freshwater generator before start up.
10. The evaporator section is pressure tested by letting hot water
circulate through the section with bypass valve for hot water in normal
running position.
11. The condenser section is pressure tested by starting the ejector
pump and letting sea water circulate through the condenser section.
NOTE! Measure and note the tightening measure before removing
tightening bolts.
NOTE! Be careful not to damage the gasket during manual cleaning.Hüseyin Nejat ÖZTEZCAN Chief Engineer
55. • Whenever the sections are dismantled, inside the chambers;
isolated layers must be checked for defects. Repair any
damage according to the maintenance guide for coating. To
preserve this coating DO NOT scrape or scratch the inside
surface of the seperator vessel.
• Whenever the seperator vessel is opened check that the
anodes are functioning. If the anodes are not functioning
and/or worn replace them.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
56. How Scale Formation Occurs in Fresh Water Generator:
The performance of fresh water generator reduces with the
formation of scales because of reduction in heat transfer
efficiency. Three scales which are normally found in fresh water
generators are:
•Calcium Carbonate, CaCO3
•Magnesium Hydroxide, Mg(OH)2
•Calcium Sulphate, CaSO4
Calcium carbonate and magnesium hydroxide scale formation
mainly depends on the temperature of operation. Calcium
sulphate scale formation depends mainly on the density of the
evaporator contents or brine.
It is recommended to operate fresh water generator at its rated
capacity, not more. More production of water than rated capacity
means higher concentration of brine and more scale formation.Hüseyin Nejat ÖZTEZCAN Chief Engineer
57. How to Minimize Scale Formation
Scale formation in fresh water generator can be controlled and
minimized by continuous chemical treatment. Their trade name
is different, like:
•Vaptreat (by “UNITOR”)
•Ameroyal (by “DREW CHEMICALS”)
These chemicals minimize calcium carbonate scale formation
and possibility of foaming.
The compound is non toxic, no-acidic, and can be used in fresh
water generator producing water for drinking purposes. It would
be continuously fed into the feed line using a metering pump or
by gravity.
Amount of chemical to be dosed depends on the capacity of
fresh water produced. Hüseyin Nejat ÖZTEZCAN Chief Engineer
61. CLEANING THE TUBES (DESCALJNG METHOD)
The fresh water generator is equipped with a heater, a condenser and a
preheater. Scale forms mainly in the heating tubes of the heater.
Chemical cleaning of the whole system can be made by fitting adapter
(option) to the corrosion plate connection of the condenser water
chamber.
Sea water boils and evaporates in the heating tubes, and consequently
sea water touching the heating tubes is considerably concentrated and
supersaturated. This is why scale is deposited in the heating tubes.
Cleaning (descaling) of the of the heating tubes should be made twice or
three times a year in general. However, the interval depends upon the
operating conditions and the properties of sea water.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
62. CLEANING METHOD:
Scale may be either peeled off by physical methods or dissolved by
chemical methods. The former includes the use of brush and drill,
the rapid cooling method, injection of pressurized water, etc., but it
is rather difficult to completely remove scale by these methods.
• CHEMICAL METHODS
a) Submerged Cleaning
Pour chemical solution into the heater through the sight hole until
the upper tube plate is soaked and leave it as it is. The time required
for cleaning varies in the thickness of scale. When the solution
becomes saturation, it has no capacity for cleaning.
In this case interchange with·new solution a few times.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
63. b) Circulated Cleaning
As the drawing shows, by fitting the adapter for the inlet of solution to
the connection of corrosion plate at cooling water inlet nozzle of
condenser water chamber, and using the socket of bottom cover for
outlet of solution, clean the whole system of heat exchangers.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
64. FRESH WATER GENERATOR TYPE VSP-36-100/125 CC/SWC
Hüseyin Nejat ÖZTEZCAN Chief Engineer
75. •Half the seawater flow - compared to other freshwater generators
only half the seawater is needed, which means smaller seawater
pumps can be used. Optimized distribution prevents dry spots and
inhibits the natural scaling process.
•Lower costs and emissions - the reduction in seawater pumping
needs has a corresponding effect on the consumption of electrical
energy. Less fuel has to be burned, which reduces both operating
costs and CO2 emissions.
•3-in-1 plate technology - The AQUA Blue incorporates the
evaporation, separation and condensation processes into a single
type of titanium plate. Desalination is handled within a single plate
pack that also contains the process vacuum. No outer shell is
necessary.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
77. The combined brine/air ejector driven by the cooling water creates
the necessary vacuum in order to lower the evaporation temperature
of the feed water.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
78. The feed water is introduced into the evaporator section through an
orifice, and is distributed into every second plate channel (evaporation
channels).
Hüseyin Nejat ÖZTEZCAN Chief Engineer
79. The hot water is distributed into the remaining channels, thus
transferring its heat to the feed water in the evaporation channels.
Having reached boiling temperature – which is lower than atmospheric
pressure – the feed water undergoes a partial evaporation and
generates a mixture of vapour and brine. The brine is separated from
the vapour and extracted by the combined brine/air ejector.Hüseyin Nejat ÖZTEZCAN Chief Engineer
80. Having passed a separation zone the vapour enters every second plate
channel in the condenser section.
The cooling water supplied distributes itself into the remaining channels,
thus absorbing the heat being transferred from the condensing vapour.
The produced fresh water is extracted by the freshwater pump and
pumped to the freshwater storage tank.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
81. DRINKING WATER TREATMENT
The low operating temperature of the evaporator is not sufficient
to sterilize. Harmful organisms may enter with the sea water and
pass through to the domestic water tank. There is a likelihood that
while in the domestic tank, water may become infested with
bacteria.
Sterilization by the addition of chlorine, is recommended.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
82. DRINKING WATER TREATMENT
• Filtration – to remove any solid particulate matter – using
carbon filter, membrane filter etc.
• Sterilisation – to remove bacteria – through chlorination, UV
treatment, ozonisation etc.
• Neutralisation – to neutralise acidic nature – add calcium or
magnesium carbonate
• Mineralisation – to add minerals required for human body by
dosing calcium or magnesium carbonate
Hüseyin Nejat ÖZTEZCAN Chief Engineer
83. Water Disinfection Methods
• Chlorine sterilization
• Ultra violet light disinfection
• Ozone water disinfection
Hüseyin Nejat ÖZTEZCAN Chief Engineer
85. CHLORINE STERILIZATION AND CONDITIONING
The distillated water is passed through a neutralite unit containing
magnesium and calcium carbonate. Some absorption of CO2 from the
water and the neutralizing effect of these compounds, removes acidity.
The addition of hardness salts also gives the water a better taste.
The sterilizing agent chlorine, being a gas, is carried into the water as a
constituent of sodium hypochlorite (a liquid) or in granules of calcium
chloride dissolved in water. The addition is set to bring chlorine content
to 0.2 ppm.
The passage of water from storage tanks to the domestic system, is by
way a carbon filter which removes the chlorine taste
Hüseyin Nejat ÖZTEZCAN Chief Engineer
87. Ultra violet light disinfection
The UV light is an effective and clean water disinfection method, it
inactivates bacterias and other harmful contaminants. UV light as a
disinfection method is non residual so is actually doesn’t leave any
disinfectant in the water.
Ozone water disinfection
Water disinfection methods also include the use of Ozone (O3), this is
a very unstable molecule which is a powerful oxidant that’s toxic for
organisms living in water. Ozone offers a very wide spectrum
disinfection ability. the Ozone must be produced on site using oxygen
and a UV light normally. Ozone disinfectant produces less hazardous by
products that Chlorine does.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
88. Some of the important points that should be considered during
maintenance of drinking water systems on ships are:
• Check Salinity Alarm: The salinity alarm or salinity indicator needs
regular checks as it allows only pure fresh water to flow into the fresh
water tank.
• Stop Fresh Water Generator At Right Time: Whenever a vessel
approaches any port, land or estuary, the Fresh Water Generator
must be stopped as at such places the sea water is heavily infected
with bacteria ,which may be transferred to the fresh water stored
onboard. As per recommended in Safety Management System
Manual or Flag State Requirements, the Fresh Water Tanks are
generally cleaned once in six months or on yearly basis.
• Use High Pressure Spray While Cleaning Tanks: While cleaning the
fresh water tanks it is advisable to use high pressure spray of fresh
water.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
89. • Be Careful While Using Chemicals and Scrubbing: Chemicals, if any,
are to be used should be biodegradable. Mostly fresh water tanks do
not get rusted and have a special coating inside. It should be kept in
mind not to scrub the tank surface too hard so that it results in
removal of coating from the tank walls.
• Take Proper Steps While Applying Paint: Paint if applied on the tank
surface must be of approved type, immiscible in water and suitable
to the surface.
• Follow Proper Enclosed Space Entry Procedures: If ship’s staff is
involved in cleaning fresh water tanks, enclosed space entry
checklist and procedures must be complied with.
• Open Separator Shell When Required: The separator shell and heat
exchanger covers can be opened up and inspected during scheduled
inspections for scale formation or if cooling tubes are fouled with
any sludge formation.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
90. • Use Scale Inhibitors: Scale inhibitors are used to prevent scale
formation by dispersing scale deposits and delaying reaction.
Scale formation inside heat exchanger requires cleaning if specific
temperatures cannot be obtained for inlet and outlet of fresh
water.
• Remove Damaged Coating: In case coating inside fresh water
generator is damaged, the damaged covering is to be scraped off
and the surface should be then thoroughly dried. After putting
the undercoat on the steel surface, epoxy-resin or food coating
(as prescribed by FWG manufacturer) is to be applied.
• Clean Drinking Water Fountains: Various drinking water fountains
inside accommodation require scheduled cleaning and
replacement of filters as well.
• Cleaning of Fresh Water Tank: The fresh water tank must be
inspected and cleaned at regular intervals of time (normally 6
months).
Hüseyin Nejat ÖZTEZCAN Chief Engineer
91. SOME FWG PHOTOS TAKEN BY ME
Hüseyin Nejat ÖZTEZCAN Chief Engineer
105. • Why fresh water generator is fitted on ships ?
To produce the high purity distilled water from sea water.
To provide make up water for boiler and portable water for
drinking and domestic use. So can save cost.
• What is temperature of Main Engine jacket cooling water
entering to fresh water generator?
It is about 80 C degree
Hüseyin Nejat ÖZTEZCAN Chief Engineer
106. • What are the causes of loss of vacuum in fresh water generator ?
•Failure of ejector pump
•Failure of ejector nozzle (fouling, erosion)
•Malfunction of check valve (at ejector nozzle)
•Defective vacuum breaker
•Any air leakage into the system (At joint)
• What will happen when vacuum reach 100% in fresh water
generator ?
1. Increase the salinity because of agitation. At that time boiling rate
is very high.
2. To control this condition, open the vacuum breaker to maintain
93% vacuum.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
107. • What are the reasons loss of facuum or over-pressure of shell?
The shell pressure of the fresh water generator rises and rate of
freshwater produced reduces. The reasons are:
1.Air leaks into the evaporator shell in large quantities and air
ejector cannot cope.
2.The cooling water flow through the condenser is reduced or
cooling water temperature is high. This cause saturation
temperature and hence saturation pressure within the condenser
to rise.
3.Malfunctioning of the air ejector.
4.Flow rate of the heating medium increased and excess water
vapour produced. Since this excess vapours cannot be condensed,
shell pressure increases or vacuum falls.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
108. • REASON FOR FRESH WATER GENERATOR SALINITY ALARM?
1. Vaccum is too high,which is leading to rapid boiling of sea water in
fresh water generator.
2. Same goes with the low waccum but with less boiling temperature.
3. Jacket water from main engine is not properly set to flow in to the
generator.
4. Brine ejector is not working properly, hence too much brine
carryover in the condensation.
5. Demister mesh, is not working properly, leading to large carryovers.
6. Vaccum relief valve or the FWG space is leaking.
7. Alarm level hes been set too low, as compared to salinity maintained
by the FWG.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
109. • What are the safeties in a FWG?
Safeties in a FWG are:
1. Vacuum breaker for releasing the vacuum at the time of shutting
down.
2. Relief Valve for releasing the excess pressure.
3. High Salinity Alarm: It is fitted to the salinometer as it measures
higher salt content in the water produced, it sounds the alarm.
4. Temperature Guage.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
110. • Where does the ejector pump takes suction from?
• What if ejector pump fails and we have to run FWG?
Ejector pump has a separate sea water suction (a separate sea chest.)
In case the ejector pump fails and we need to run the FWG, there is a
separate line from fire and general service pump as the discharge
pressure of this pump is around 3-4 bar and ejector pump discharges at
pressure not less than 4 bar.
Main sea water cannot be used ın this case because main sea water
pump has discharge pressure around 1-2 bar.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
111. • What are the reasons salt water carry over (Priming)?
Salt water may be carried over in large quantities during operation
of the freshwater generator. This is called priming. General reasons
of the priming are:
1.Level of salt water inside the shell is high. When water level is high
agitation due to boiling occurs and salt water may carry over along
with the vapours.
2.When the salt water brine density is too high, agitation of salt
water occurs which results in priming.
3.Increased evaporation rate.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
112. • What are the reasons of the gradual increase in level of brine?
For the satisfactory operation of the freshwater generator, a
constant level of brine to be maintained in the shell.
Brine is the concentrated sea water after liberation of water
vapours.
This brine is gradually extracted from the shell. Usually this is
achieved by the combined air-brine ejector. It extracts air as well as
brine from the shell.
Any fault in the ejector or ejector pump cause increase in the brine
level.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
113. • Reasons for increase in Salinity of Freshwater?
Possible causes are:
1.Brine level inside shell too high.
2.Leaking condenser tubes or plates.
3.Operation of evaporator near shore with contaminated feed water.
4.Shell temperature and pressure too low.
5.Increased solubility of CO2 generated from the salt water due to
reduced sea water temperature. This dissolved CO2 makes water
acidic and conductivity of water increases.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
114. Salinity of distilled water produced from fresh water generator onboard depends on
A. Amount of feed set in fresh water production
B. Amount of salt water leaking from condenser if any
C. Temperature of the sea water used
D. Efficiency of brine ejector from the evaporator shell
Answer-A, C & D
Scale formation in a fresh water generator evaporator can lead to _____________
A. Impaired heat transfer
B. Reduced capacity
C. Increased shell temperature
D. All of the above
Answer-D
Amount of distilled water produced in fresh water generator onboard decreases with
A. Increase in vacuum in the fresh water generator shell
B. Decrease in sea water temperature
C. Decrease in efficiency of heat exchanger
D. Increase in sea water temperature
Answer-C and D
Hüseyin Nejat ÖZTEZCAN Chief Engineer
115. . A high reading at a salinity cell located in the loop seal between
two stages of a flash type evaporator would indicate ______.
a) chill shocking is necessary to remove scale
b) leakage at the second-stage condenser
c) faulty operation of the brine overboard pump
d) carryover in the first-stage
• In which of the following Fresh Water Generators would an air
ejector be unnecessary?
a) Reverse Osmosis Unit
b) Submerged tube type FWG Unit
c) Plate type FWG Unit
d) Flash Type FWG Unit
Hüseyin Nejat ÖZTEZCAN Chief Engineer
117. REVERSE OSMOSIS
Reverse Osmosis (RO) is one of the methods which are used on
board for generating fresh water.
Generally this is used on passenger vessels wherein there is a large
requirement of fresh water production.
However, in merchant ships the evaporation method is used as
reverse osmosis is costly and includes large maintenance cost for
membrane.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
118. Osmosis
To understand the purpose and process of Reverse Osmosis you must
first understand the naturally occurring process of Osmosis.
Osmosis is a naturally occurring phenomenon and one of the most
important processes in nature. It is a process where a weaker saline
solution will tend to migrate to a strong saline solution. Examples of
osmosis are when plant roots absorb water from the soil and our
kidneys absorb water from our blood.
What is meant by Osmosis ?
•When different concentration solutions are separated by a semi-
permeable membrane, water from less concentrated solution pass to
the other solution through the membrane to equalize the concentration
of the two solution.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
119. Working Principle Of RO:
Osmosis describes the process whereby a fluid will pass from a
more dense to a less dense solution through a semi-permeable
membrane.
It is very important to the water absorbtion processes of plants.
RO is a process which uses a semi- permeable membrane which
retains both salt and impurities from sea water while allowing
water molecules to pass.
Filtration of up to 90% is possible thus making the produced water
unsuitable for boiler feed without further conditioning. Improved
quality is possible using a two or more pass system
Hüseyin Nejat ÖZTEZCAN Chief Engineer
120. What is meant by Reverse Osmosis ?
•The pressure greater than the osmotic pressure is applied to the
side of higher concentration solution, the osmosis process
is reversed.
•Water from the stronger solution is forced back through the semi-
permeable membrane to dilute the initially weak solution on the
other side and further increase the concentration of the
strong solution. The total pressure required for this process
consists of the osmotic pressure (up to 28 bar for sea water)
plus the system pressure losses and net driving pressures
(around 25 bar).
Hüseyin Nejat ÖZTEZCAN Chief Engineer
122. A semi-permeable membrane is a membrane that will allow some
atoms or molecules to pass but not others.
A simple example is a screen door. It allows air molecules to pass
through but not pests or anything larger than the holes in the
screen door.
Another example is Gore-tex clothing fabric that contains an
extremely thin plastic film into which billions of small pores have
been cut. The pores are big enough to let water vapor through, but
small enough to prevent liquid water from passing.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
126. How does Reverse Osmosis work?
Reverse Osmosis works by using a high pressure pump to increase
the pressure on the salt side of the RO and force the water across
the semi-permeable RO membrane, leaving almost all (around 95%
to 99%) of dissolved salts behind in the reject stream.
The amount of pressure required depends on the salt concentration
of the feed water. The more concentrated the feed water, the more
pressure is required to overcome the osmotic pressure.
The desalinated water that is demineralized or deionized, is called
permeate (or product) water.
The water stream that carries the concentrated contaminants that
did not pass through the RO membrane is called the reject (or
concentrate) stream.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
128. Salt Rejection %
This equation tells you how effective the RO membranes are
removing contaminants. It does not tell you how each individual
membrane is performing, but rather how the system overall on
average is performing.
A well-designed RO system with properly functioning RO membranes
will reject 95% to 99% of most feed water contaminants. You can
determine effective the RO membranes are removing contaminants
by using the following equation:
The higher the salt rejection, the better the system is performing.
A low salt rejection can mean that the membranes require cleaning or
replacement. Hüseyin Nejat ÖZTEZCAN Chief Engineer
129. Salt Passage %
This is simply the inverse of salt rejection described in the previous
equation.
This is the amount of salts expressed as a percentage that are
passing through the RO system.
The lower the salt passage, the better the system is performing.
A high salt passage can mean that the membranes require cleaning
or replacement.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
130. Recovery %
Percent Recovery is the amount of water that is being 'recovered' as
good permeate water. Another way to think of Percent Recovery is the
amount of water that is not sent to drain as concentrate, but rather
collected as permeate or product water.
The higher the recovery % means that you are sending less water to
drain as concentrate and saving more permeate water.
However, if the recovery % is too high for the RO design then it can lead
to larger problems due to scaling and fouling.
The % Recovery for an RO system is established with the help of design
software taking into consideration numerous factors such as feed water
chemistry and RO pre-treatment before the RO system.
Therefore, the proper % Recovery at which an RO should operate at
depends on what it was designed for.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
131. By calculating the % Recovery you can quickly determine if the
system is operating outside of the intended design.
For example, if the recovery rate is 75% then this means that for
every 100 gallons of feed water that enter the RO system, you are
recovering 75 gallons as usable permeate water and 25 gallons are
going to drain as concentrate.
Industrial RO systems typically run anywhere from 50% to 85%
recovery depending the feed water characteristics and other design
considerations.
The calculation for % Recovery is below:
Hüseyin Nejat ÖZTEZCAN Chief Engineer
133. RO Membrane Cleaning
RO membranes will inevitably require periodic cleaning, anywhere
from 1 to 4 times a year depending on the feed water quality.
As a general rule, if the normalized pressure drop or the normalized
salt passage has increased by 15%, then it is time to clean the RO
membranes.
If the normalized permeate flow has decreased by 15% then it is
also time to clean the RO membranes.
You can either clean the RO membranes in place or have them
removed from the RO system and cleaned off site by a service
company that specializes in this service. It has been proven that
offsite membrane cleaning is more effective at providing a better
cleaning than onsite cleaning skids.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
135. One problem with any filtration system is that deposits accumulate
and gradually blocks the filter.
-The sea water is supplied at a pressure of about 60 bar, a relief
valve is fitted to the system.
-The Osmosis production plant is best suited to the production of
large quantities of water rather than smaller quantities of steam
plant feed quality.
SEMI PERMEABLE MEMBRANE: The semi permeable membrane
which is typically made of polyamide membrane sheets wrapped in
a spiral form around a perforated tube resembling a loosely wound
like a toilet paper roll.
The material used for sea water purification is spirally wound
polyamide or polysulphonate sheets.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
136. Pretreatment and post treatment
Sea water feed for reverse osmosis plant is pretreated before being
passed through.
The chemical sodium hexa- phosphate is added to assist wash
through of salt deposits on the surface of the elements and the sea
water is steriliazed to remove bacteria which could otherwise
become resident in the filter.
Chlorine is reduced by compressed carbon filter while solids are
removed by other filters.
Treatment is also necessary to make the water drinkable.
Hüseyin Nejat ÖZTEZCAN Chief Engineer
137. Reverse Osmosis process flow chart.
SEA WATER
SAND FILTRATION
ANTISCALANT DOSING
CARTRIDGE FİLTRATION
HP FEED PUMP
MEMBRAN
FRESH WATERHüseyin Nejat ÖZTEZCAN Chief Engineer
139. Backwashing:
Backwashing of the filters is carried out to remove the
accumulated solid particulates from the filtering media layers; it
involves reversing the normal flow and discharging it to waste.
Backwashing is carried out on a set frequent depending upon the
feed quality or if the differential pressure increases by 1.0 bar
between the inlet to the outlet.
The backwash flow rate will vary depending upon the feed water
temperature. It is critical that the correct flow rate is used; a
satisfactory wash may not be achieved if it is too low or, on the
other hand, media may be washed away if the wash water flow
rate is too high.
Hüseyin Nejat ÖZTEZCAN Chief Engineer