This presentation discusses the design of overpressure and underpressure protection systems. It covers the root causes of overpressure and underpressure such as equipment failures or process upsets. The key elements of protection systems are presented, including relief devices, effluent handling systems, preventing runaway reactions, and safeguards against fires and explosions. The goal is to help engineers properly design plants to protect against overpressure and underpressure incidents.
Pressure Relief Valve Sizing for Single Phase FlowVikram Sharma
This presentation file provides a quick refresher to pressure relief valve sizing for single phase flow. The calculation guideline is as per API Std 520.
Pressure Relief Systems
BACKGROUND TO RELIEF SYSTEM DESIGN Vol.1 of 6
The Guide has been written to advise those involved in the design and engineering of pressure relief systems. It takes the user from the initial identification of potential causes of overpressure or under pressure through the process design of relief systems to the detailed mechanical design. "Hazard Studies" and quantitative hazards analysis are not described; these are seen as complementary activities. Typical users of the Guide will use some Parts in detail and others in overview.
Pressure Relief Valve Sizing for Single Phase FlowVikram Sharma
This presentation file provides a quick refresher to pressure relief valve sizing for single phase flow. The calculation guideline is as per API Std 520.
Pressure Relief Systems
BACKGROUND TO RELIEF SYSTEM DESIGN Vol.1 of 6
The Guide has been written to advise those involved in the design and engineering of pressure relief systems. It takes the user from the initial identification of potential causes of overpressure or under pressure through the process design of relief systems to the detailed mechanical design. "Hazard Studies" and quantitative hazards analysis are not described; these are seen as complementary activities. Typical users of the Guide will use some Parts in detail and others in overview.
Excel sheet Download Link: https://www.scribd.com/document/385945712/PSV-Sizing-Tool-API-Based-Calc-Sheets
PSV Sizing for Blocked Liquid Discharge Condition
PSV Sizing for Blocked Gas Discharge Condition
PSV Sizing for Fire Case of Liquid Filled Vessel
PSV Sizing for Control Valve Fail Open Case
Relief Valve Sizing for Thermal Expansion
Restriction Orifice Sizing for Gas Flow
Restriction Orifice Sizing for Liquid Flow
Single Phase Flow Line Sizing Tool
Gas Control Valve Sizing Tool
Safety is the most important factor in designing a process system. Some undesired conditions might happen leading to damage in a system. Control systems might be installed to prevent such conditions, but a second safety device is also needed. One kind of safety device which is commonly used in the processing industry is the relief valve. A relief valve is a type of valve to control or limit the pressure in a system by allowing the pressurised fluid to flow out from the system.
Process Safety Management (PSM) is a concern in any of the industries who store, handle and process hazardous chemicals & gases. The risks related to process safety are often managed in an isolated way.
This presentation will help organisations to manage process safety risks in a more structured fashion.
Importance & requirement of Rupture Disk in Industry. Sizing and selection of Safety Relief valves and Rupture Disks. Selection and types of rupture disks. Sizing calculation of rupture disks, PRVs and determination of required relief load.
Piping Training course-How to be an Expert in Pipe & Fittings for Oil & Gas c...Varun Patel
Course Description
Piping a must know skill to work in Oil & Gas and similar Process Industries.
Oil and Gas industry is become a very competitive in the current time. Getting right mentor and right exposer within industry is difficult. With limited training budget spent by company on employee training, it is difficult to acquire the knowledge to success.
Knowing cross-functional skill give you an edge over others in your career success.
This course design based on years of field experience to ensure student will comprehend technical details easily and enjoy overall journey.
Learn in detail every aspect of Pipe & Pipe Fittings used in process industry
•Different types of Pipe, Pipe fittings (Elbow, Tee, reducers, Caps etc.), Flanges, Gaskets, Branch Connection, Bolting materials
•Materials (Metal-Carbon Steel, Stainless Steel, Alloy Steel etc. Non-Metal- PVC/VCM, HDPE, GRE-GRP etc.)
•Manufacturing methods
•Heat treatment requirements
•Inspection and Testing requirements (Non Destructive Testing, Mechanical & Chemical testing)
•Dimensions & Markings requirements
•Code & Standard used in piping
Content and Overview
With 2 hours of content including 30 lectures & 8 Quizzes, this course cover every aspect of Pipe, Pipe fittings, flanges, gaskets, branch connections and bolting material used in Process Piping.
This Course is divided in three parts.
1st part of the course covers fundamental of process industries. In this Part, you will learn about fundamental process piping. You will also learn about Code, Standard & Specification used in process industries.
2nd part cover various types of material used in process industries. In this part, you will learn about Metallic and Non-Metallic material used to manufacture pipe and other piping components.
3rd parts covers in detail about pipe and piping components used in Process piping. In this part we will learn about Industry terminology of Piping components, types of industrial material grade used in manufacturing and entire manufacturing process of these components. You will learn about different manufacturing methods, Heat treatment requirements, Destructive and Non-destructive testing, Visual & Dimensional inspection and Product marking requirements.
Upon completion, you will be able to use this knowledge direct on your Job and you can easily answer any interview question on pipe & fittings.
Confined Space Entry
Hazardous Substances In Refineries
Hazards of Air and Oxygen
Hazards of Electricity and Static Electricity
Hazards of Nitrogen and Catalyst Handling
Hazards of Steam
Hazards of Trapped Pressure and Vacuum
Hazards of Water
Hotel Fire Safety
Liquid Hydrocarbon Tank Fires
Safe Handling of Light Ends
Safe Furnace and Boiler Firing
Safe Tank Farms and (Un)loading Operations
Safe Ups and Downs for Process Units
Control of Work
Accumulation and Over-pressure: difference between accumulation and overpressureVarun Patel
Accumulation is pressure above the maximum allowable working pressure that vessel experience during high pressure event. Hence, when we say ‘accumulation’, its mean we are talking about the vessel or equipment.
On the other hand, Overpressure is pressure above the set pressure of the pressure safety valve that PSV experience during high pressure event. Hence, when we say ‘accumulation’, its mean we are talking about the pressure relief valve.
Pressure Safety Valve Sizing - API 520/521/526Vijay Sarathy
No chemical process facility is immune to the risk of overpressure to avoid dictating the necessity for overpressure protection. For every situation that demands safe containment of process gas, it becomes an obligation for engineers to equally provide pressure relieving and flaring provisions wherever necessary. The levels of protection are hierarchical, starting with designing an inherently safe process to avoid overpressure followed by providing alarms for operators to intervene and Emergency Shutdown provisions through ESD and SIL rated instrumentation. Beyond these design and instrument based protection measures, the philosophy of containment and abatement steps such as pressure relieving devices, flares, physical dikes and Emergency Response Services is employed
Eng handbook crosby pressure relief valve engineering handbookAli Meshaikhis
Reference is made to the ASME Boiler and Pressure Vessel Code, Section VIII, Pressure Vessels. The information in this handbook is not to be used for the application of overpressure protection to power boilers and nuclear power plant components which are addressed in the ASEM Boiler and Pressure Vessel Code Section I.
Piping Design Course is very Important today. Basically, Piping is the work of Providing and Maintaining the Water Supply, Replacing Pipes and Pipe Work. SEA has trained & certified more than 3000 Engineers & Individuals in last five ( 5 ) years in different engineering disciplines and various sectors which include Oil and Gas , Petrochemicals , Refineries , Power Plant , Aeronautics & Construction projects etc. SEA certification / qualification is accepted and recognized by major National & International companies in the world including India , Saudi Arabia , UAE , Kuwait , Qatar , Bahrain , Oman , Jordan , Iraq , Iran , Yemen , Nigeria , Sudan , Libya , Turkey ,Portugal, Cameroon, Congo & other countries. Our SEA certified Engineers are already working in the above said countries.
Killer smoke defeted for the first time in history. The Latest Development of...Dave Atkinson
This is the latest news and development on the Blueproof device for ALARM conference in June. The UPADI (Unión Panamericana de Asociaciones de Ingenieros) to be held in a conference in Bolivia Santa Cruz in August and for the UK Chief Fire Officers Association.
Excel sheet Download Link: https://www.scribd.com/document/385945712/PSV-Sizing-Tool-API-Based-Calc-Sheets
PSV Sizing for Blocked Liquid Discharge Condition
PSV Sizing for Blocked Gas Discharge Condition
PSV Sizing for Fire Case of Liquid Filled Vessel
PSV Sizing for Control Valve Fail Open Case
Relief Valve Sizing for Thermal Expansion
Restriction Orifice Sizing for Gas Flow
Restriction Orifice Sizing for Liquid Flow
Single Phase Flow Line Sizing Tool
Gas Control Valve Sizing Tool
Safety is the most important factor in designing a process system. Some undesired conditions might happen leading to damage in a system. Control systems might be installed to prevent such conditions, but a second safety device is also needed. One kind of safety device which is commonly used in the processing industry is the relief valve. A relief valve is a type of valve to control or limit the pressure in a system by allowing the pressurised fluid to flow out from the system.
Process Safety Management (PSM) is a concern in any of the industries who store, handle and process hazardous chemicals & gases. The risks related to process safety are often managed in an isolated way.
This presentation will help organisations to manage process safety risks in a more structured fashion.
Importance & requirement of Rupture Disk in Industry. Sizing and selection of Safety Relief valves and Rupture Disks. Selection and types of rupture disks. Sizing calculation of rupture disks, PRVs and determination of required relief load.
Piping Training course-How to be an Expert in Pipe & Fittings for Oil & Gas c...Varun Patel
Course Description
Piping a must know skill to work in Oil & Gas and similar Process Industries.
Oil and Gas industry is become a very competitive in the current time. Getting right mentor and right exposer within industry is difficult. With limited training budget spent by company on employee training, it is difficult to acquire the knowledge to success.
Knowing cross-functional skill give you an edge over others in your career success.
This course design based on years of field experience to ensure student will comprehend technical details easily and enjoy overall journey.
Learn in detail every aspect of Pipe & Pipe Fittings used in process industry
•Different types of Pipe, Pipe fittings (Elbow, Tee, reducers, Caps etc.), Flanges, Gaskets, Branch Connection, Bolting materials
•Materials (Metal-Carbon Steel, Stainless Steel, Alloy Steel etc. Non-Metal- PVC/VCM, HDPE, GRE-GRP etc.)
•Manufacturing methods
•Heat treatment requirements
•Inspection and Testing requirements (Non Destructive Testing, Mechanical & Chemical testing)
•Dimensions & Markings requirements
•Code & Standard used in piping
Content and Overview
With 2 hours of content including 30 lectures & 8 Quizzes, this course cover every aspect of Pipe, Pipe fittings, flanges, gaskets, branch connections and bolting material used in Process Piping.
This Course is divided in three parts.
1st part of the course covers fundamental of process industries. In this Part, you will learn about fundamental process piping. You will also learn about Code, Standard & Specification used in process industries.
2nd part cover various types of material used in process industries. In this part, you will learn about Metallic and Non-Metallic material used to manufacture pipe and other piping components.
3rd parts covers in detail about pipe and piping components used in Process piping. In this part we will learn about Industry terminology of Piping components, types of industrial material grade used in manufacturing and entire manufacturing process of these components. You will learn about different manufacturing methods, Heat treatment requirements, Destructive and Non-destructive testing, Visual & Dimensional inspection and Product marking requirements.
Upon completion, you will be able to use this knowledge direct on your Job and you can easily answer any interview question on pipe & fittings.
Confined Space Entry
Hazardous Substances In Refineries
Hazards of Air and Oxygen
Hazards of Electricity and Static Electricity
Hazards of Nitrogen and Catalyst Handling
Hazards of Steam
Hazards of Trapped Pressure and Vacuum
Hazards of Water
Hotel Fire Safety
Liquid Hydrocarbon Tank Fires
Safe Handling of Light Ends
Safe Furnace and Boiler Firing
Safe Tank Farms and (Un)loading Operations
Safe Ups and Downs for Process Units
Control of Work
Accumulation and Over-pressure: difference between accumulation and overpressureVarun Patel
Accumulation is pressure above the maximum allowable working pressure that vessel experience during high pressure event. Hence, when we say ‘accumulation’, its mean we are talking about the vessel or equipment.
On the other hand, Overpressure is pressure above the set pressure of the pressure safety valve that PSV experience during high pressure event. Hence, when we say ‘accumulation’, its mean we are talking about the pressure relief valve.
Pressure Safety Valve Sizing - API 520/521/526Vijay Sarathy
No chemical process facility is immune to the risk of overpressure to avoid dictating the necessity for overpressure protection. For every situation that demands safe containment of process gas, it becomes an obligation for engineers to equally provide pressure relieving and flaring provisions wherever necessary. The levels of protection are hierarchical, starting with designing an inherently safe process to avoid overpressure followed by providing alarms for operators to intervene and Emergency Shutdown provisions through ESD and SIL rated instrumentation. Beyond these design and instrument based protection measures, the philosophy of containment and abatement steps such as pressure relieving devices, flares, physical dikes and Emergency Response Services is employed
Eng handbook crosby pressure relief valve engineering handbookAli Meshaikhis
Reference is made to the ASME Boiler and Pressure Vessel Code, Section VIII, Pressure Vessels. The information in this handbook is not to be used for the application of overpressure protection to power boilers and nuclear power plant components which are addressed in the ASEM Boiler and Pressure Vessel Code Section I.
Piping Design Course is very Important today. Basically, Piping is the work of Providing and Maintaining the Water Supply, Replacing Pipes and Pipe Work. SEA has trained & certified more than 3000 Engineers & Individuals in last five ( 5 ) years in different engineering disciplines and various sectors which include Oil and Gas , Petrochemicals , Refineries , Power Plant , Aeronautics & Construction projects etc. SEA certification / qualification is accepted and recognized by major National & International companies in the world including India , Saudi Arabia , UAE , Kuwait , Qatar , Bahrain , Oman , Jordan , Iraq , Iran , Yemen , Nigeria , Sudan , Libya , Turkey ,Portugal, Cameroon, Congo & other countries. Our SEA certified Engineers are already working in the above said countries.
Killer smoke defeted for the first time in history. The Latest Development of...Dave Atkinson
This is the latest news and development on the Blueproof device for ALARM conference in June. The UPADI (Unión Panamericana de Asociaciones de Ingenieros) to be held in a conference in Bolivia Santa Cruz in August and for the UK Chief Fire Officers Association.
Malfunctions in Solar Thermal InstallationsSekem Energy
Solar Thermal Conference "Paving ways together for solar thermal energy in Egypt" at Heliopolis University, Cairo, on 18th May 2016
"Most common malfunctions of solar thermal systems", Mr. Markus Reischl, Solarexpert
Fire, Pressure & Ice – Oh My! Motion Control in Hostile EnvironmentsDesign World
Some of the most challenging and rewarding motion control applications are not made difficult because of the complexity of the machine but rather due to the hostile environments in which the application must succeed. From arctic conditions in biomedical cryogenic laboratories to the low pressure, high altitude skies that most commercial aircrafts operate, learning the particular nuances of harsh environments is a necessity to many manufacturers, machine builders, and system integrators.
Join Hack Summer of Moog Animatics as we explore some of the common (and most underestimated) hostile environments for motion control applications. Get application examples along with expert tips for designing motion control systems for hostile environments, a brief first look at Moog Animatics’ new extended range integrated motion control systems and best practices learned from over 20 years’ experience in military and commercial motion control design.
Watch this webinar to learn:
- What explosion proof really means for motion control systems?
- Which hostile environments benefit from integrated motion control systems vs. conventional motion control systems?
- Why temperature isn’t the biggest concern for aerospace applications – and what is?
- What questions to ask when buying ‘extended temperature range’ products?
How can machine learning be used to optimize control of a waste water treatment plant? This talk is a practical walk-though of an applied AI project. It discusses how to use a neural network trained in Tensorflow to replace failing sensors, and how to use reinforcement learning for optimizing real-time control of an industrial facility.
First Passive House Retrofit in a Cold Climate: The MinnePHit HouseTE Studio
This presentation was given by Tim Delhey Eian of TE Studio on Tuesday, September 23rd, at the 2014 NAPHN Passive House Conference in Portland, Maine. It showcases the first cold climate Passive House retrofit (EnerPHit) project which TE Studio designed, and the Passivhaus Institut in Darmstadt (Germany) certified as a pilot EnerPHit project.
Similar to Design for Overpressure and Underpressure Protection (17)
The performance based approach involves the assessment of three basic components comprising the likely fire behaviour, heat transfer to the structure and the structural response. The overall complexity of the design depends on the assumptions and methods adopted to predict each of the three design components.
Fire model for sizing high consequence areas associated with natural gas pipe...Thapa Prakash (TA-1)
The subject report is developing by Prakash Thapa Memorial University St. Johns, Newfoundland, Canada for the Research unite in Oil Gas and Safety Engineering for Memorial University St. John’s Newfoundland Canada. The report was dated November 20th 2015 and the report’s recommended equation for determining potential impact radius (PIR) of a natural gas pipeline rupture is included in 49 CFR 192.903. This PIR equation is given as:
5. Causes of Overpressure
• Operating Problem
• Equipment Failure
• Process Upset
• External Fire
• Utility Failures
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11. Buckling Pin Relief Valve
Closed
Pressure Below
Set Pressure
Full Open
Pressure at or Above
Set Pressure
(Buckles in Milliseconds at a Precise Set Pressure)
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Text
13. Types of Spring-Loaded
Pressure Reliefs
• Safety Valves for Gases and Vapors
• Relief Valves for Liquids
• Safety Relief Valves for Liquids
and/or Gases
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14. Types of Safety Valves
• Conventional
• Balanced Bellows, and
• Pilot-Operated
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29. Presentation 2 of 3: Runaways
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Causes ofCauses of
Overpressure/UnderpressureOverpressure/Underpressure
Presentation 1: ReliefsPresentation 1: Reliefs
Presentation 2: RunawaysPresentation 2: Runaways
Presentation 3: SafeguardsPresentation 3: Safeguards
30. Runaway Reaction
• Temperature Increases
• Reaction Rate Increases
• Pressure Increases
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31. Causes of Runaway Reactions
• Self-Heating
• Sleeper
• Tempered
• Gassy
• Hybrid
Characteristics of Runaway
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32. Self-Heating Reaction
• Loss of Cooling
• Unexpected Addition of Heat
• Too Much Catalyst or Reactant
• Operator Mistakes
• Too Fast Addition of Catalyst or Reactant
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33. Sleeper Reactions
• Reactants Added But Not Mixed
(Error)
• Reactants Accumulate
• Agitation Started .. Too Late
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34. Tempered Reaction
• Heat Removed by Evaporation
• Heat Removal Maintains a Constant
Temperature
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35. Gassy System
• No Volatile Solvents
• Gas is Reaction Product
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37. Reliefs for Runaway Reactions
• Two Phase (or Three Phases:
Liquid, Vapor, and Solid) Flow
• Relief Area: 2 to 10 Times the
Area of a Single Gaseous Phase
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43. Safety Interlocks
• Agitator Not Working: Stop Monomer
Feed and Add Full Cooling
• Abnormal Temperature: Stop
Monomer Feed and Add Full Cooling
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44. Safety Interlocks
(continued)
• Abnormal Pressure: Stop Monomer Feed
and Add Full Cooling
• Abnormal Heat Balance: Stop Monomer
Feed and Add Full Cooling
• Abnormal Conditions: Add Short-Stop
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48. Protection Methods for
Internal Fires and Explosions
• Deflagration Venting
• Deflagration Suppression
• Containment
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49. Protection Methods for
Internal Fires and Explosions
(continued)
• Reduction of Oxidant
• Reduction of Combustible
• Flame Front Isolation
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50. Protection Methods for
Internal Fires and Explosions
(continued)
• Spark Detection and Extinguishing
• Flame Detection and Extinguishing
• Water Spray and Deluge Systems
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IntroductionIntroduction
ReliefsReliefs
RunawaysRunaways
SafeguardsSafeguards Home
Causes of Overpressure
• Operating Problem
The major causes of overpressure include:
• Operating problems or mistakes such as an operator mistakenly
opening or closing a valve to cause the vessel or system pressure to
increase. An operator, for example, may adjust a steam regulator to
give pressures exceeding the maximum allowable working pressure
(MAWP) of a steam jacket. Slide
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Causes of Overpressure
• Operating Problem
• Equipment Failure
• Equipment failures; for example a heat exchanger tube rupture that
increases the shell side pressure beyond the MAWP. Although the set
pressure is usually the MAWP, the design safety factors should protect
the vessel for higher pressures; a vessel fails when the pressure is
typically several times the MAWP.
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Causes of Overpressure
• Operating Problem
• Equipment Failure
• Process Upset
• External Fire
• Utility Failures
• Process upset; for example a runaway reaction causing high
temperatures and pressures.
• External heating, such as, a fire that heats the contents of a vessel
giving high vapor pressures, and
• Utility failures, such as the loss of cooling or the loss of agitation
causing a runaway reaction. Slide
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RunawaysRunaways
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Buckling Pin Relief Valve
Closed
Pressure Below
Set Pressure
Full Open
Pressure at or Above
Set Pressure
(Buckles in Milliseconds at a Precise Set Pressure)
This sketch shows a buckling pin pressure relief valve. As
shown, when the pressure exceeds the set pressure, the pin
buckles and the vessel contents exit through the open valve.
The rupture disc and the buckling pin relief valves stay open
after they are opened.
Slide
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SafeguardsSafeguards Home
Types of Spring-Loaded
Pressure Reliefs
• Safety Valves for Gases and Vapors
• Relief Valves for Liquids
• Safety Relief Valves for Liquids
and/or Gases
There are three types of spring-loaded pressure relief valves:
• Safety valves are specifically designed for gases.
• Relief valves are designed for liquids, and
• Safety relief valves are designed for liquids and/or gases.
Slide
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Pressure or Vacuum Control
• Add Air or Nitrogen
• Maintain Appropriately
Sometimes pressure or vacuum control systems are used to add air or
nitrogen to the vessel to maintain a slight pressure. In this case, the
system needs to be appropriately maintained because a malfunction
could result in an overpressure or under-pressure. In either case the
consequence could be a ruptured vessel.
Slide
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Runaway Reaction
• Temperature Increases
• Reaction Rate Increases
• Pressure Increases
A runaway reaction is an especially important overpressure scenario. A
runaway reaction has an accelerating rate of temperature increase, rate
of reaction increase, and usually rate of pressure increase. The
pressure, of course, increases if the reaction mass has a volatile
substance, such as, a solvent or a monomer; or if one of the reaction
products is a gas. Slide
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Causes of Runaway Reactions
• Self-Heating
• Sleeper
• Tempered
• Gassy
• Hybrid
Characteristics of Runaway
When protecting a system for overpressures due to runaway reactions
the engineer needs to know the type of runaway and needs to
characterize the behavior of the specific runaway with a special
calorimeter. This specific methodology is described in this section of this
presentation.
Slide
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Sleeper Reactions
• Reactants Added But Not Mixed
(Error)
• Reactants Accumulate
• Agitation Started .. Too Late
Sleeper reactions are usually the result of an operator error. Two
examples include: (a) the addition of two immiscible reactants when the
agitator is mistakenly in the off position, and (b) the addition of a reactant
to the reaction mass when the temperature is mistakenly lower than that
required to initiate the reaction.
Slide
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Tempered Reaction
• Heat Removed by Evaporation
• Heat Removal Maintains a Constant
Temperature
Tempered runaway reactions maintain their temperature when the
energy exiting the relief device is equal to the energy generated in the
reactor due to the exothermic reaction. The reaction heat is absorbed by
the evaporation of the volatile components. The vapor pressure in a
tempered system can typically be characterized by an Antoine type
equation. Slide
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Reliefs for Runaway Reactions
• Two Phase (or Three Phases:
Liquid, Vapor, and Solid) Flow
To maintain a constant temperature in the reactor (i.e. control the
runaway reaction), the relief valve is sized to remove all the heat
generated from the exothermic reaction via the heat removed with the
discharged mass, which is typically a foam. Detailed information on
runaway reactions is found in the appendix.
Slide
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Two Phase Flow
This is a picture that illustrates the two-phase flow
characteristics of a relief discharge due to a runaway reaction.
As illustrated, the discharge is similar to the release of foam
from a freshly opened bottle of pop after being shakened. If the
relief is not designed for two-phase flow, the pressures would
increase rapidly and the vessel could rupture. Slide
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Relief Valve Sizing
Methodology
• Special Calorimeter Data
• Special Calculation Methods
The relief valve sizing methodology for runaway reactions is
very complex. It requires the characterization of the runaway
reaction using a specially designed calorimeter.
Relief valve sizing, additionally, requires special calculation
methods that are described in the Appendix of this package.
Slide
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Safety Interlocks
• Agitator Not Working: Stop Monomer
Feed and Add Full Cooling
• Abnormal Temperature: Stop
Monomer Feed and Add Full Cooling
The list of alternative interlocks is fairly extensive. Usually more than
one interlock and some redundancy and diversity is required for each
runaway scenario. As the number of interlocks increases, the reliability
of the system increases. These are examples of safety interlocks for a
semibatch polymerization reactor.
Slide
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Short-Stops to Stop Reaction
• Add Reaction Stopper
• Add Agitation with No Electrical
Power
A short-stopping system, stops a runaway reaction by adding a
reaction stopper solution to the reacting mass. The reaction-
stopper stops the reaction in time to short-circuit the progress of the
reaction. A reaction stopper needs to be added when the reaction
mass is relatively cold. If the mass is too hot, a short-stopper will
not work. Slide
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Short-Stops to Stop Reaction
• Add Reaction Stopper
• Add Agitation with No Electrical
Power
Good agitation, of course, is required to adequately mix the reaction
mass with the inhibitor. Since a power failure is often the initiating
event of a runaway, an alternative method of agitation needs to be
included in the design. A compressed nitrogen system together
with a spare ring is one alternative.
Slide
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Vent of Gas Deflagration
This is a picture of the venting of a gas deflagration. As illustrated,
the flame propagates a significant distance from the vessel. The
length of the flame is estimated using an equation found in NFPA
68. The main purpose of venting is to protect the mechanical
integrity of the equipment. As illustrated, even when it is vented
safely, this is a major event. Slide
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Vent of Dust Deflagration
This is a picture of the venting of a dust deflagration. As illustrated,
the burning dust continues to burn at great distances from the vent.
With dusts, this burning zone is larger because the container has a
larger fuel-to-air ratio compared to the gas deflagration scenario.
These pictures clearly illustrate the problems with venting
deflagrations. Slide
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IntroductionIntroduction
ReliefsReliefs
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Reduction of Oxidant
• Vacuum Purging
• Pressure Purging
• Sweep-Through Purging
Protection for overpressures is also provided with an inert gas
blanket to prevent the occurrence of a deflagration. Before
introducing a flammable substance to a vessel, the vessel must
also be purged with an inert gas to reduce the oxidant
concentration sufficiently so that the gas mixture cannot burn.
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