The document discusses a solution developed to address repeated failures of diaphragm welds in refinery heat exchangers. The solution involved eliminating the diaphragm plate and replacing it with a double-tapered, self-energizing metal pressure seal. Finite element analysis validated that the seal would keep components in an elastic state with stresses below code limits. The retrofit successfully eliminated cracking as the root cause of leaks, increasing equipment reliability while reducing downtime and costs during maintenance.
Terminology, Control Valve Basic Designs, Characterization and Trim Design, Control Valve Technical Considerations, Force-Balance Principle, Actuator Basic Designs, Control Valve Unit Action, Actuator Benchset Range, Valve Positioner Basics, Control Loop Action, Control Valve Packing Designs, Seat Leakage
Terminology, Control Valve Basic Designs, Characterization and Trim Design, Control Valve Technical Considerations, Force-Balance Principle, Actuator Basic Designs, Control Valve Unit Action, Actuator Benchset Range, Valve Positioner Basics, Control Loop Action, Control Valve Packing Designs, Seat Leakage
its easy to size the chilled water pipe in app or riser in two step only just cal. the water gpm and plotted in red area ., now read the minimum pipe size and select the min. water velocity
Types Of Centrifugal Fans Used In Power Plant BoilersNeelRao
The purpose of boiler in thermal power plants is to covert water into steam with the help of heat energy generated by the combustion of fuels like coal, wood, oil or natural gas.
Valve and instrumentation calibration and maintenance will assures the accuracy of your industrial instrumentation and valves in accordance with relevant standards
THINKTANK®️ is the leading manufacturer of control valves in China, we focus on the production and development of pneumatic or electric globe type control valves, self-operated pressure regulator and double-seat control valves
The stress analysis basis used in the ASME Code to analyze the nozzle reinforcement is called Beams on
Elastic Foundation (Hetenyi, 1946). This method determines the effectiveness of the material close to the
opening for carrying loads. Reinforcement limits are developed parallel and perpendicular to the shell surface
near the opening. Although the method is a simplified application of the elastic foundation theory, experience
has shown that it does a good job.
Values from two equations are used to set the reinforcement limits measured along the vessel wall surface.
The greater value sets the horizontal limit for that opening. The first value is equal to d, and the second
value is equal to 0.5d + t + tn as shown in Fig. 5.2. The relationship of the nozzle wall thickness
PRINCIPAL OF COOLING TOWER
TYPES OF COOLING TOWER
DIFFERENT TERMS USED IN COOLING TOWER SPECIFICATION
AIR PROPERTIES AND
SIZING OF COOLING TOWER HEIGHT
TYPICAL SPECIFICATION FORMAT / DATASHEET
This manual covers the basic guidelines and minimum requirements for
periodic inspection of heat exchangers used in petroleum refinery.
Locations to be inspected, inspection tools, frequency of inspection &
testing, locations prone to deterioration and causes, corrosion
mitigation, inspection and testing procedures have been specified in
the manual.
Documentation of observations & history of heat exchangers,
inspection checklist and recommended practices have also been
included.
Heat exchanging equipment is used for heating or cooling a fluid.
Individual heat transfer equipment is named as per its function.
Cooler
A cooler cools the process fluid, using water or air, with no change of
phase.
Chiller
A chiller uses a refrigerant to cool process fluid to a temperature below
that obtainable with water.
Condenser
A condenser condenses a vapour or mixture of vapours using water or
air.
Exchanger
An exchanger performs two functions in that it heats a cold process
fluid by recovering heat from a hot fluid, which it cools. None of the
transferred heat is lost.
Est group harbin urea conference 2014 pap paper v1 englishJim Novak (吉因龙)
An Improved Tube Plugging Technique for Ammonia and Urea Plant Heat Exchangers. Eliminates Welding, Reduces Downtime and Increases Reliability
We will provide details documenting the development of Pop-A-Plugs specifically for this service and how this significantly reduces the shutdown time required to seal tubes in such service. Everybody knows that welded plugs in high pressure heat exchangers in urea plants are prone to leaking problems as the proper quality of the welds is difficult to assure. Pop-A-Plug® System plugs promise a much better reliability than welded plugs.
its easy to size the chilled water pipe in app or riser in two step only just cal. the water gpm and plotted in red area ., now read the minimum pipe size and select the min. water velocity
Types Of Centrifugal Fans Used In Power Plant BoilersNeelRao
The purpose of boiler in thermal power plants is to covert water into steam with the help of heat energy generated by the combustion of fuels like coal, wood, oil or natural gas.
Valve and instrumentation calibration and maintenance will assures the accuracy of your industrial instrumentation and valves in accordance with relevant standards
THINKTANK®️ is the leading manufacturer of control valves in China, we focus on the production and development of pneumatic or electric globe type control valves, self-operated pressure regulator and double-seat control valves
The stress analysis basis used in the ASME Code to analyze the nozzle reinforcement is called Beams on
Elastic Foundation (Hetenyi, 1946). This method determines the effectiveness of the material close to the
opening for carrying loads. Reinforcement limits are developed parallel and perpendicular to the shell surface
near the opening. Although the method is a simplified application of the elastic foundation theory, experience
has shown that it does a good job.
Values from two equations are used to set the reinforcement limits measured along the vessel wall surface.
The greater value sets the horizontal limit for that opening. The first value is equal to d, and the second
value is equal to 0.5d + t + tn as shown in Fig. 5.2. The relationship of the nozzle wall thickness
PRINCIPAL OF COOLING TOWER
TYPES OF COOLING TOWER
DIFFERENT TERMS USED IN COOLING TOWER SPECIFICATION
AIR PROPERTIES AND
SIZING OF COOLING TOWER HEIGHT
TYPICAL SPECIFICATION FORMAT / DATASHEET
This manual covers the basic guidelines and minimum requirements for
periodic inspection of heat exchangers used in petroleum refinery.
Locations to be inspected, inspection tools, frequency of inspection &
testing, locations prone to deterioration and causes, corrosion
mitigation, inspection and testing procedures have been specified in
the manual.
Documentation of observations & history of heat exchangers,
inspection checklist and recommended practices have also been
included.
Heat exchanging equipment is used for heating or cooling a fluid.
Individual heat transfer equipment is named as per its function.
Cooler
A cooler cools the process fluid, using water or air, with no change of
phase.
Chiller
A chiller uses a refrigerant to cool process fluid to a temperature below
that obtainable with water.
Condenser
A condenser condenses a vapour or mixture of vapours using water or
air.
Exchanger
An exchanger performs two functions in that it heats a cold process
fluid by recovering heat from a hot fluid, which it cools. None of the
transferred heat is lost.
Est group harbin urea conference 2014 pap paper v1 englishJim Novak (吉因龙)
An Improved Tube Plugging Technique for Ammonia and Urea Plant Heat Exchangers. Eliminates Welding, Reduces Downtime and Increases Reliability
We will provide details documenting the development of Pop-A-Plugs specifically for this service and how this significantly reduces the shutdown time required to seal tubes in such service. Everybody knows that welded plugs in high pressure heat exchangers in urea plants are prone to leaking problems as the proper quality of the welds is difficult to assure. Pop-A-Plug® System plugs promise a much better reliability than welded plugs.
2018 Hydrogen & Fuel Cells Energy Summit - Haskel Unveils New Hydrogen Techno...Haskel International
At the 2018 Hydrogen & Fuel Cells Energy Summit in Brussels, Belgium, the newest Haskel technology was unveiled. Haskel Product Engineer Pooya Mahmoudian presented on prevention methods for H2 embrittlement in pressure vessels and discussed an entirely new industry technology that has the potential to dramatically impact prices for companies developing hydrogen refueling stations.
Review Mahmoudian's presentation to learn more about Haskel's new technology and the advancements we're making in hydrogen technology.
Improved Material and Enhanced Fatigue Resistance for Gear ComponentsALD Vacuum Systems Inc.
Abstract
This paper shows the latest progress in steel grades and in case hardening technology for gear components.
To answer the demand for fuel-efficient vehicles, modern gear boxes are built much lighter. Improving fatigue resistance is a key factor to allow for the design of thin components to be used in advanced vehicle transmissions. The choice of material and the applied heat treat process are of key importance to enhance the fatigue resistance of gear components.
By applying the technology of Low Pressure Carburizing (LPC) and High Pressure Gas Quenching (HPGQ), the tooth root bending strength can be significantly enhanced, compared to traditional heat treatment with atmospheric carburizing and oil quenching.
Besides heat treatment, significant progress has been made over the past years on the steels being used for gear components. The hardenability of case hardening steels such as 5130H, 5120H, 20MnCr5, 27MnCr5, 18CrNiMo7-6 etc. has been stepwise increased in recent years. An important factor for fatigue resistance is the grain size after heat treatment. Therefore, grain size control is a key goal when developing new modifications of steel grades.
After enhancing grain size control, it was possible to increase the carburizing temperatures over the past years from 930°C to 980°C (1700°F to 1800°F) which resulted in shorter heat treatment cycles and thus in significant cost savings.
With the introduction of new microalloyed steels for grain size stability, carburizing temperatures can now be even further increased to temperatures of up to 1050°C (1920°F), leading to even more economic process cycles. By adding microelements such as Niobium or Titanium in the ppm-range, nitride and carbonitride-precipitates are formed. These precipitates effectively limit the grain-growth during the heat treatment process.
Goel Scientific General information and introductionGoel Scientific
Borosilicate glass represents unmatched standardized glass for construction of plant
and piping in the chemical, dyestuff, food pharmaceutical, petrochemical industries. Its
steadily growing use is due to many advantages over conventional materials.
Platinflex, which is headquartered in Istanbul (Turkey), belongs to one of the largest internationally active groups in the Manufacture,development of metal hoses and metal hose assemblies for the most diverse range of Refrigeration and cooling industries
Underwater welding is an important tool for underwater fabrication works.
In 1946, special waterproof electrodes were developed in Holland by ‘Vander Willingen'’.
In recent years the number of offshore (inside the water) structures including oil drilling rigs, pipelines, platforms are being installed significantly
BIC Magazine - Tapered Pressure Seal Eliminates Diaphragm in Heat Exchanger
1. Schematic of exchanger design
with diaphragm
Schematic of exchanger design
with tapered seal
Tapered pressure seal
being installed in heat exchanger
DRAFT for BIC
Tapered Pressure Seal Eliminates Diaphragm in Heat Exchanger
Opportunity for implementation
During the refinery restart following hurricane Rita
in September 2005, a leak occurred in a
Hydrotreater exchanger. A small crack
developed in the channel cover plate diaphragm
weld.
With both hurricanes Katrina and Rita crippling
plants along the nations third coast, refineries
were requested to restart operations as quickly
and safely possible to provide fuel for the
massive clean up.
Having been faced with repeated failures of the
diaphragm welds in the refinery coupled with the
sense of urgency to get our nations transportation
system flowing developing a solution became a
priority. An “outside-the-box” solution was required.
The solution involved eliminating the diaphragm
plate entirely and replacing it with a double-
tapered, self-energizing metal pressure seal as it
was simple, effective and quite field compatible
within the timeframe of the downtime.
The double-tapered, self-energizing metal
pressure seal, manufactured by Taper-Lok
consisted of seal ring or gasket with dual,
converging angles that create a wedge or “door
stop” effect. As the equipment internal pressures
increases, the Taper-Lok seal seats tighter.
The seal is made from the same material as the
process equipment (exchanger channel and cover)
to ensure that thermal expansions are consistent
across all components. The effects of bi-metallic
(galvanic) corrosion are eliminated. A baked-on
moly coating is applied to the seal to prevent
galling.
This promising sealing technology required minor
modifications to the heat exchangers. It was
simple, reusable, provided a metal-to-metal seal,
and took very little time to make the modification.
The Problem
It is not uncommon for diaphragm plates in high
pressure heat exchangers to develop cracks in their
seal welds. The diaphragm, which is generally a
thin plate of alloy steel serves as the gasket and corrosion resistant liner for the channel cover (Figure
2. 1). This arrangement is common for heat exchangers in hydrogen services at operating pressures
above 1600 psig in our refinery’s Gas Oil Hyrdotreater (GOHT) unit. We have had multiple diaphragm
leaks over the past several years.
Hydrotreater units are expensive to build. Their high pressure and elevated temperatures necessitate
heavy wall vessels, piping and ancillary equipment. Their severe service often requires exotic
metallurgy. The preferred method of fabrication is butt-welding due to material and equipment costs
and to prevent possible leak locations. These constraints often minimize block valve installations
between equipment and any possibility of isolating or “bypassing” equipment, without taking the
complete unit down.
From a business perspective, hydrotreater units required to meet the low sulfur fuel specifications that
are now in effect. Hydrotreater units are critical to a refinery’s balance sheet.
There are several reasons why cracks can develop. Reasons include the following:
Tensile overload caused by differences in the thermal expansion of the low alloy steel channel
(carbon or Cr-Mo) and the SS diaphragm.
Chloride Stress Corrosion Cracking (SCC) – A salt which drops out in hydrotreater effluent
exchangers is ammonium chloride. The diaphragm is susceptible to this failure mode due to its
high residual stress.
Polythionic Acid Stress Corrosion Cracking – Hydrotreater effluent systems use austenitic SS for
sulfidation resistance. Polythionic acids are formed in the process during shutdown periods when the
prevalent metal sulfide scale react with oxygen and water condensed during the steam out cleaning
process.
Double Taper Seal Technology
Reliability Assessment and Risk Mitigation of Seal
The seals had performed well in temperatures from cryogenic to 1600 degrees F and at pressures to
40,000 psig. Applications of note included: heat exchanger internals, hydrogen processing, high
temperature measurement equipment, offshore (both sub-sea and topside) and high pressure
compressor connections.
A study conducted by JP Kenny proved to be helpful. The results of the study showed that the
pressure seal was preferable to ANSI standard gaskets connections.
A design of the seal for one of our heat exchanger was created and calculations according to ASME
Section VIII, Division 1 Unfired Pressure Vessels7
were conducted to ensure code compliance
A finite element analysis (FEA) was conducted consisting of both 2D and 3D nonlinear models with
contact elements. The analysis verified that the seal would be kept in an elastic state and that the
stresses in the components would be below code allowable limits.
Conclusion
Several benefits were realized from this retrofit. The largest being the elimination of the cracking which
in turn increased equipment reliability and unit availability. Having the seal fabricated from the same
material as the pressure parts (channel and cover), bi-metallic or galvanic corrosion cannot occur. All
thermal expansion observed during operation is constant. The seal or “gasket” is in compression and in
an elastic state. The seal is self energized, creating a tighter seal with any increase in pressure.
Elements that promote the cracking are eliminated.
Additional benefits, some initially unforeseen, were the reduced cost or downtime from several items
such as the following:
3. the reduction in the exchanger turnaround time from six shifts to three shifts
the utilization of one crane in lieu of two (1 for cover plate and 1 for impact)
the elimination of any hydrogen bake out from weld contamination and weld dilution on alloy
exchangers with a stainless steel corrosion overlay
the elimination of machining of weld build up (Nickel butter coat)
the elimination of seal weld and metal diaphragm seal
the elimination of NDE to search for cracking throughout the entire process
Downtime has decreased since the root cause of the process leaks (cracking of diaphragm welds) at
the cover have been eliminated. The retrofit was deemed a success. No downside opportunities have
been observed or foreseen.