SY/T 10043-2002 Guidelines for pressure relief and decompression systems
Some standard content:
ICS 75.180.10
Registration number: 10486-2002
Petroleum and natural gas industry standard of the People's Republic of China SY/T 10043-2002
Replaces SY/T4812-92
Guide for pressure - relieving and depressuring systems2002- 05-28 Issued
National Economic and Trade Commission
2002-08-01 Implementation
Before 4PI
API Policy statement
Chapter 1 Overview
1.1 Application
1, 2 References (omitted)
1.3 Terms and definitions
Chapter 2 Overpressure causes
2.1 Overview
2.2 Criteria for judging gradual overpressure
2.3 Possible overpressure causes
Chapter 3 Determination of single-item release room
3.1 Main causes of overpressure
Overpressure source
3.3 Influence of pressure, temperature and composition
3.4 Influence of operator response….
3.5 Outlet closed
3.6 Cooling or reflux interruption
Absorbent flow suspension
Accumulation of non-condensables
Volatile substances entering the system
Process system automatic control failure
Abnormal heat input to the process system
Internal explosion (excluding deflagration)
Chemical reaction
Hydraulic expansion
External fire
Opening of movable valves
Electrical failure
Failure of heat transfer equipment
Steam pressure reduction
Special considerations for individual valves
References (omitted)
Chapter 4
“Selection of treatment system
Overview
Fluid properties affecting design
4.3 Atmospheric emissions
Flare treatment
SY/T 10043-—2002
SY/T 10043—20-02
4.5 Treatment of discharge to low-pressure system
4.6 Treatment of liquids and condensable vapors·
4.7 References (omitted)
4.8 References (omitted)
Chapter 5 Treatment system
5.1 Overview·
5.2 Determination of system load
5.3 System layout
5.4 Treatment system unit equipment
5.5 Flare gas recovery system·
5.6 References (omitted)
Chapter 6 References
6.1 Treatment system·
6.2 Tanks and separators
6.3 Flares and smoke·| |tt||6.4 Flushing flow in pipelines
6.5 Flushing flow in valves
6.6 Piping systems
6.7 Piping criteria and pipe racks
6.8 Repulsion relief valves
6.9 Bursting discs
6.10 Water hammer and pressure transition
6.11 Systems
Appendix A (Normative Appendix)
Determination of fire relief requirements
Appendix B (Normative Appendix) Issues to be considered in the design of special systems Appendix C (Normative Appendix) Example of flare tower height gauge stool Appendix ") (Normative Appendix) Typical details and schematics Figure 1 Average heating rate of steel plate side exposed to gasoline flame Figure 2 Effect of overheating (ASTMA515 Figure 3 Phase equilibrium diagram for a given liquid
Figure 4 Pressure level
Figure 5 Maximum downwind vertical distance from the diffusion outlet to the lean combustible concentration area (LPG) Figure 6 Maximum downwind horizontal distance from the diffusion outlet to the lean combustible concentration area (LPG) Figure 7 Axial distance to the lean combustible concentration area and the rich combustible concentration area (LPG) Figure 8 Relationship curve between flame length and heat release: industrial size and release amount (U.S. general units) Figure 9 Flame length The relationship curve between degree and heat release: 1 Industry size and release amount (metric units) Figure 1) Approximate result of flame change caused by the influence of side wind on the injection velocity of the flare tower··Figure 11
Smokeless flare head injected with water vapor
Typical air-assisted combustion torch system
White support structure
Guard rope support structure
Figure 15 Tower support structure
Purge gas flow rate reduction seal
Molecular type
: 46
Figure 17 Purge gas velocity reduction seal - velocity or venturi single tubeFigure 18 Isothermal flow profile
Figure 19 Adiabatic flow of a compressible fluid through a pipeline under high pressure dropFigure 20
Determination of drag coefficient
Flare separator tank
Vapor length required for elevated flare
Sound intensity 100 ft (30 m) from the tower headFigure 24
Typical flare gas recovery system
Inlet pressure of flare gas recovery system
Vapor pressure and heat of vaporization of pure single component liquid alkanesTypical flow diagram and pressure curve of a pressure relief device in a process systemReference size of flare tower
Horizontal distance between the flame mouth and the ignition discharge of the flare3. (U.S. general units)Horizontal distance between the flame mouth and the ignition discharge of the flare. (Metric units) Vertical distance between the center of the flame of a flare and the ignition outlet (U.S. customary units) Figure C.5
Vertical distance between the center of the flame of a flare and the ignition outlet (Metric units).1
Flare sealing tank·
Quench tank·
Typical flare installation
Table 1 Table 11 Typical K values for various pipe fittings
Table 12 Typical friction coefficients for clean steel pipes (based on an equivalent machine roughness of 0.50015 ft) Table 13 Dimensions of optimized horizontal separator tanks (U.S. customary units) Table 14 Dimensions of optimized horizontal separator tanks (metric units) Table 1: Comparison of heat absorption rates in open flame tests SY/T 10043—2002
SY/T 10043-2002
In order to meet the needs of developing offshore gas resources in my country, China National Offshore Oil Corporation uses AIRI521 "Recomrred Practice for Guide for Pressure Relieving and Depressuring Systuris" 1997 edition of the American Petroleum Institute. This standard replaces the original SY/I4812-92 "Guide to Pressure Relief and Decompression Systems" which is equivalent to APIRP521:1982 and is published as a new standard for the natural gas industry:
This revision makes its meaning more accurate, the content more complete, and easier for users to understand. Compared with the previous version, this standard has added the following chapters: "Special Statement", Chapter 3 3.15\External Fire\3.15.1~3.15.5 and 3.18 Heat Transfer Equipment Failure"13.18.2~3.18.3, Chapter 4 4.4\Flare Handling"4.4.3, Chapter 5 5.4\Design of Single Units of Handling Systems\5.4.1 and 5.5\Flare Gas Collection Systems", Appendix A (Normative Appendix)\Determination of Fire Relief Requirements" Appendix F (Normative Appendix)\Special System Design Considerations Compared with the previous version, the following chapters of this standard have been greatly modified, and some new content has been added: "API first six", Chapter 1, Chapter 2 2.2 "Criteria for judging over-rejection", Chapter 3 3.1 "Main causes of over-rejection", 3.10 "Process system self-control and rescue", 3.11 "Abnormal heat input to process system", 3.12 "Internal explosion (excluding deflagration)", 3.13 "Chemical reaction", 3.14 "Hydraulic expansion", 3.15 "External fire", 3.18 "Heat transfer equipment failure", 3.19 "Steam reduction", 3.20 "Special considerations for single valves", 3.21 "References (omitted)", Chapter 4 "4.4 Flare treatment", 4.7 "References (omitted)", 4.8 "References (omitted)", Chapter 5 5.4 "Design of single processing system", 5.6 "Reference". Other chapters have also been modified, adjusted, added or deleted. For details, see the main text. In order to facilitate users to consult the original text, except for the obvious inappropriate parts found in the text that have been modified according to the requirements of GB1.1, the Chinese layout is basically the same as the original text and has not been changed.
In the design, construction and use of offshore oil and gas development projects, when laws, regulations and provisions of the government or other local authorities of the country where the original standard is located are involved, the data or quantitative calculation methods of environmental conditions such as wind, waves, currents, ice, overflow, earthquakes, etc. in the original standard shall be implemented in accordance with the relevant laws, regulations and provisions promulgated by the government of the People's Republic of China or its relevant departments. All data and quantitative calculation methods that conform to the actual conditions of my country can be used as a reference; otherwise, the data and quantitative calculation methods that conform to the actual environmental conditions of my country shall be used as a reference. Regarding the expression of measurement units, the legal measurement units of my country shall be mainly used, that is, the legal measurement unit values are in front, and the corresponding values of the American general units are marked in brackets after them.
In order not to change the formulas in the original standard and to maintain the shape characteristics of the curve, the relevant American general units originally used in the formulas and curves are not changed.
From the date of entry into force, this standard will replace the Appendix A, Appendix B, Appendix C, and Appendix D of SYT4812-92, which are all normative appendices. This standard is proposed and managed by China National Offshore Oil Corporation. This standard was drafted by: Development and Design Institute of Research Center of China National Offshore Oil Corporation. The main drafter of this standard: Xu Liying
The chief reviewer of this standard: Zhu Haishan.
API Foreword
SY/T10043—2002
This recommended practice is compiled as a guide for the design, installation and operation of pressure relief and reduction systems for equipment engineering. Based on the accumulated knowledge and experience of qualified engineers in the petroleum industry and related fields, the standard recommends economically reasonable and safe pressure relief practices. Before the publication of this recommended practice, there was no such document available for reference: the formulation of APIIRP520 "Recommended Practice for Sizing, Selection and Installation of Refinery Pressure Relief Devices" published the existing detailed information in this regard. Recommended Practice APIRP521 is a compilation of these and related data and is published as an appendix to APII520. As modern process equipment becomes more and more complex in design and operation, the energy level of the equipment highlights the importance of carefully designed and reliable pressure relief systems. This recommended practice presents suggestions for immediate design, economic, and safety issues surrounding pressure relief venting systems. However, users of this recommended practice are cautioned that a publication of this type cannot be considered complete, nor can any comprehensive document be a substitute for sound engineering analysis. This edition includes editorial revisions and major changes based on experience gained with the third edition. Metric numbers, unit names, and formulas are included in the English version of the API publications. API publications are available to anyone who wishes to use them. The Institute has made every effort to ensure the accuracy and reliability of the data contained therein: however, the Institute makes no representation, warranty, or guarantee with respect to this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from the use of this publication or for any conflict of regulations that may occur as a result of the use of this publication that may be inconsistent with any federal, state, or municipal regulation. Suggestions for revisions are welcome and should be addressed to the Director, Manufacturing, Distribution, and Marketing, American Petroleum Institute, 1220 LStrcct, AW, Washington. I). C. 20005.W
SY/T10043—2002
API Policy Statement
AFI's various publications address general topics only. When it comes to specific situations, local, state and federal laws and regulations should be consulted:
API does not assume any obligation for employers, manufacturers or suppliers to warn, strictly train and equip their employees and other personnel on the job about health and safety risks and preventive measures, nor does it assume any responsibility beyond local, state or federal laws. Information about the safety and health risks involved in individual materials and conditions and the corresponding preventive measures should be obtained from the employer, the manufacturer or supplier of the material, or from the safety data sheet of the material. The content of any AI publication shall not be construed as granting any right, by implication or otherwise, to make, sell or use any patented method, apparatus or product. Nothing in this publication shall be construed to excuse anyone from liability for infringement of patent rights.
Generally, AF1 standards are reviewed at least every 5 days. The period of validity of this publication shall not exceed 5 years from the date of publication unless an extension of validity is authorized for reprinting. The status of this publication may be obtained from the AFI Editorial Office at (202) 682-8000. API (1220 LST, NW, Washington, DC 20005) publishes a monthly directory of API publications and materials and updates them quarterly. This recommended practice was developed in accordance with the API standardization process, which ensures that it is as comprehensive and representative as possible during the standards development process to become an API standard. Questions concerning the interpretation of the content of this standard or suggestions for improving the standard procedures should be addressed directly to the Editorial Director, AHI (marked on the front page of this recommended practice), American Petroleum Institute, 1220 LST, NW, Washington, DC 20005, Df20005.
American Petroleum Institute (API) standards are published for the purpose of disseminating proven good engineering and operational practices. These standards are not intended to obviate the need for proper judgment as to when and where these standards should be applied: the development and publication of API standards is not intended to prohibit anyone from adopting other practices.
Any manufacturer of equipment marked in accordance with the marking requirements of an API standard is solely responsible for complying with the requirements of the applicable API standard. API does not represent, warrant, or guarantee that these products actually conform to the applicable API standard. 1.1 Scope
Guide to Pressure Relief and Pressure Reduction Systems
Chapter 1 Overview
SY/T 100432002
This standard applies to pressure relief and steam pressure reduction systems. The information provided is intended to assist in selecting the most suitable relief and pressure reduction systems for various installations when hazardous conditions occur. The purpose of this standard is to supplement the practices specified in AFPIRP520I Sizing, Selection and Installation of Refinery Pressure Relief Devices Part I Sizing and Selection (Fifth Edition) in order to establish a design basis. This standard provides guidance for analyzing the main causes of overpressure, determining the amount of individual releases, and selecting and designing processing systems such as vessels, flares and vent towers.
Piping information related to pressure relief systems is presented in 5.4.1 of this standard. However, the actual pipeline should be designed in accordance with ASME (American Society of Mechanical Engineers) H31.3 or other applicable codes: Health hazards may be associated with the operation of pressure relief equipment. Discussion of special risks is beyond the scope of this standard. 1.2 References (omitted)
1.3 Terms and Definitions
This standard provides definitions of terms used in 1.3.1 to 1.3.37 related to pressure relief systems: Many terms and definitions are taken from API RP520 I and ASME PIC25
Pressure accumulation
The pressure increment exceeding the maximum allowable working pressure of the container when the pressure relief device is discharging; the pressure accumulation value is expressed in pressure units or white fractions. The maximum allowable pressure accumulation value is determined based on the applicable standards for operation and fire accidents. 1.3.2
Atmospheric discharge
Vapors and gases are discharged to the atmosphere through pressure relief and pressure relief devices. 1.3.3
Back pressure
The pressure existing at the outlet of the pressure relief device due to the pressure in the discharge system. Back pressure may be constant or variable. Back pressure is the sum of superimposed back pressure and accumulated back pressure.
Balanced pressure relief valveA type of spring-loaded relief valve that minimizes the effect of back pressure on the operating characteristics of the pressure relief valve (see API RP520 I).
Relief pressure differential Howdowm
The difference between the set pressure and the closing pressure of the pressure relief valve, expressed as a fraction of the set pressure or in pressure units. 1.3.6
E huilt - up back pressure
Accumulated back pressure
The pressure increment established in the discharge manifold due to the flow of the medium after one or more pressure relief devices are opened: 1.3.7
Burst pressure
The static pressure at the inlet that causes the bursting disc device to operate. SY/T 10043—2002
Closed bonnet pressure relief valve Closed bonnet pressure relief valve The entire spring is mounted on a metal shield. The metal shield prevents the spring from contacting the corrosive media in the environment and is used to collect leakage around the valve stem and valve disc guide. Whether the bonnet is sealed to prevent the pressure inside the valve from escaping into the surrounding atmosphere depends on the type of bonnet lift cup used or the special treatment of the bonnet vent. 1.3.9
Closed dispnsal system can handle pressurized processing systems different from atmospheric pressure. 1.3.10
Cold differential test pressure The pressure at which the pressure relief valve is adjusted on the test bench to the opening pressure. The cold test differential pressure includes the correction value for back pressure or temperature or both under working conditions.
conventionalpressurereliefvalveConventionalpressurereliefvalve
A spring-loaded pressure relief valve whose operating characteristics are directly affected by changes in the back pressure of the valve (see APIRP520T). 1.3.12
The design pressure of a vessel is at least the most unfavorable superposition of operating temperature and pressure expected during operation. It can be used instead of the maximum allowable working pressure in various situations where the maximum allowable operating pressure has not yet been determined. The design pressure is the pressure used in the design to determine the minimum allowable wall thickness of the vessel or to determine the physical properties of the non-commercial parts of the vessel (see maximum allowable working pressure). 1.3.13
Flare
A method of safely handling gases by combustion. For an elevated flare, the combustion is carried out with the help of a burner and igniter mounted on the top of a pipe or tower. For a ground flare, the equipment is similar to that of an elevated flare, except that the combustion is carried out at or near the ground. The difference between a burn pit and a flare is that the burn pit soil is used to handle liquids. 1.3.14
Huddling chamber
An annular pressure chamber installed outside the pressure relief valve seat, its function is to quickly open the valve. 1.3.15
Lift
The actual lift of the valve disc from the closed position when the valve is relieving. 1.3.16
Maximum allowable accumulated pressuremaximum allnwahlc accumulated pressureThe sum of the maximum allowable working pressure and the maximum allowable pressure product. 1.3.17
maximum allowable working pressure
The maximum allowable gauge pressure at the top of the vessel under operating conditions and design temperature. This pressure is determined based on the calculation results of each component of the vessel when the nominal wall thickness is applied. It does not include corrosion allowances and additional metal wall thickness required for loads other than pressure. The maximum allowable working pressure is the basis for the pressure setting of the pressure relief device that protects the vessel. 1.3.18
Open-bonnet pressure relief valveOpen-bonnet pressure relief valve is a pressure relief valve in which the spring passes through the bonnet or seat and is directly exposed to the atmosphere. According to the design, the spring can be protected from contact with the steam or natural gas discharged by the valve, and is cooled by the flowing air around the spring. 2
Open disposing systemOpen dispasal system is a disposing system that uses only a short tail pipe to discharge directly from the discharge device to the atmosphere without using a container. 1.3.20
Operating pressureOperating pressure
SY/T 10043—2002
The pressure that the container is subjected to during normal use. In order to prevent any unnecessary action of the relief device, the maximum allowable working pressure of the pressure vessel is usually designed with an appropriate margin above the operating pressure. 1.3.21
Overpressure
The pressure increment exceeding the set pressure of the pressure relief device, expressed in pressure units or percentages: When the pressure relief device is set according to the maximum working pressure of the vessel and it is assumed that there is no pressure loss in the inlet pipe system to the pressure relief device, it is equal to the accumulated pressure. Note: When the set pressure of the first or second pressure relief valve is lower than the maximum allowable working pressure of the vessel, the maximum pressure relief valve set pressure can be exceeded by 10%: www.bzxz.net
Pilot-controlled pressure relief valve pilot-controlled pressure relief valve main valve and auxiliary pressure relief valve of the main valve 1.3.23
Pressure relief valve pressure relief valve general name for pressure relief valves, safety valves and safety relief valves. The small relief valve is designed to automatically overlap and stop the flow of fluid. 1.3.24
Pressure-relieving system consists of pressure-relieving devices, pipelines and processing systems, and is used to safely release, transport and dispose of steam, liquids or gases. A pressure relief system may consist of only one pressure relief valve or safety bursting disc, with or without a relief pipe, which may be installed in a single container or pipeline. A more complex pressure relief system may include multiple pressure relief devices, all of which are connected to the same manifold and transported to the processing equipment.
Quenching
The cooling caused by the mixing of a liquid with other cryogenic liquids.1.3.26
Rated relieving capacityThe measured relieving capacity according to appropriate specifications or regulations, which is the basic data for selecting a monthly pressure relief device.1.3.27
Relief valve
A spring-loaded relief valve actuated by the static pressure upstream of the valve. The opening of this valve is generally proportional to the pressure increment exceeding the opening repulsion force. The pressure relief valve is mainly used for non-compressible liquids.1.3.28
Relief condition relieving The term conditions is used to indicate the inlet pressure and temperature of a pressure relief device at a specific overpressure. The relief pressure is equal to the valve setting force (or bursting pressure of a bursting disc) plus the overpressure. Under the relief conditions, the temperature of the flowing liquid may be higher than or lower than the operating temperature. 1.3.29
bursting disc deviceupturedisk device
A non-reclosing differential pressure relief device that acts by static pressure before the bursting disc is released, and relies on the rupture of a pressurized bursting disc to work. The bursting disc device consists of a bursting disc and a clamp:
SY/T10043—2002
Safety relief valvesafetyreliefvalve
A spring-loaded pressure relief device that can be used as a safety valve or a relief valve depending on the application conditions. 1.3.31
Locked block valvesealedblockvalve
A valve that can be locked in a fully open or fully closed state during normal operation. Locking can be achieved by a locking device or a locking device (see ASME "Boiler Pressure Relief Device Code" Volume LIC:-135, M-5 and M-6) (hereinafter referred to as A.SME "Code"). 1.3.32
Safety valvesafety valve
.A spring-loaded relief device driven by static pressure and having the characteristics of quick opening or sudden action. Safety valves are generally used for compressible fluids.
Set pressure
The pressure relief valve is set to open at the gauge pressure under the conditions of use. 1.3.34
Stampedburstpressurc refers to the pressure difference between the two ends of the bursting disc at the temperature when the bursting disc ruptures. This pressure is the data obtained by the manufacturer from the sampling bursting test of the same batch of bursting discs. The nameplate bursting pressure is printed on the bursting disc. The bursting discs at the initial production stage should be stamped with l.Set burst pressure.
SuperimposedbackpressureThe static pressure at the outlet of the pressure relief device before it opens. It comes from other power sources in the discharge system. It can be a constant or a variable.
Vapor depressuring systemA protective device consisting of valves and pipelines. The device reduces the pressure in the equipment by releasing the steam inlet velocity. The system can be driven automatically or manually.
Vent stack
A type of elevated vertical processing facility that discharges the discharged fluid into the atmosphere without combustion or treatment. Chapter 2 Causes of overpressure
2.1 Overview
This chapter discusses the main causes of overpressure in refinery equipment and provides guidelines for equipment design to minimize the effects of these causes. Overpressure is caused by an imbalance or abnormality in the normal flow of materials and energy. Overpressure will cause materials or energy or both to accumulate in a certain part of the system. Therefore, when analyzing the cause and magnitude of overpressure, it is an important and complex task to study the balance of materials and energy in the process system. For each process system, the application of the principles described in this chapter is different. Although this standard has tried to cover all major situations, readers are cautioned not to regard the overpressure conditions described as the only cause of overpressure. The overpressure treatment methods provided in this standard can only be used as recommendations. When designing the system, any situation that may constitute a danger in the system under various working conditions should be considered. The pressure relief device is installed to ensure that the pressure in the system or any part of it does not exceed the maximum allowable accumulation positive pressure. 2.2 Criteria for Judging Overpressure
If there is no process or mechanical or electrical connection between the causes of overpressure, or if the time interval between the causes of overpressure that may occur successively is long enough to classify them separately, then the causes of overpressure, including external fire sources, are considered independent. If these causes are independent, then two or more simultaneous occurrences that can cause overpressure are not assumed. Operator error is the root cause of overpressure. The practices described in this chapter should be combined with good engineering judgment and full consideration should be given to federal, state, and local government regulations and laws:
In addition, some relief schemes require the installation of a highly sophisticated protective instrument system to prevent overpressure and/or overtemperature. If this scheme is used, the protective instrument system should be at least as reliable as the pressure relief device system and should be used only when the pressure relief device cannot be used.
Accidental safety devices, self-starting devices and other control instruments with regulations cannot replace pressure relief devices as a protection for individual process equipment. However, when designing certain units of a relief system, such as relief manifolds, flares and flare heads, it can be assumed that the instrument system will have an appropriate instrument response percentage, and its value can be calculated based on the allowable margin, repair cycle and other factors affecting instrument reliability. 2.3 Possible causes of overpressure
2.3.1 Overview
Pressure vessels, heat exchangers, operating equipment and piping are designed according to the system pressure they are subjected to. The design is based on (a) normal operating pressure at operating temperature; (b) the influence of any combination of possible mechanical loads and the influence of different operating temperature differences; (c) the set pressure of the pressure relief device. The designer of the above process system must determine the minimum relief volume to prevent the pressure in the equipment from exceeding the maximum allowable accumulation pressure. The main causes of overpressure listed in 2.3.2 to 2.3.16 of this chapter can be used as a guide for formulating generally acceptable safety measures. 2.3.2 Vessel Outlet Closure
When the plant is in operation, if the block valve of a pressure vessel outlet is inadvertently closed, the pressure in the vessel may exceed the maximum allowable working pressure. If the outlet block valve is closed, overpressure may occur. Unless the management process controls the closure of the valve, such as installing a locking device or a lock, a pressure relief device needs to be installed. The abnormal operation of each control valve port should be considered. Generally, the block valve is omitted on the series vessel outlet to simplify the pressure relief requirements: For system capacity design, it can be assumed that the control valve always operates in the normal operating position, the valve is usually open, and it can also function in the event of a fault and is not affected by the main fault cause. For additional information, see 3.10.4. 2.3.3 Inadvertent Valve Opening
The inadvertent opening of valves connected to high pressure sources such as high pressure steam or high pressure process fluids should be considered. Unless these valves are locked or locked in the closed position by a lock, the plan requires the installation of a pressure relief device to control the amount of discharge. 2.3.4 Check Valve Failure
The failure of a check valve to close properly must also be considered. For example, if the fluid being delivered by the pump contains gas or vapor and the design repulsion greatly exceeds the design pressure of the upstream equipment, a check valve failure will cause liquid backflow after the pump is shut down. When the high-pressure fluid flows back into the suction system of the pump, serious overpressure may occur. As long as there is no potential for the backflow of high-pressure fluid in excess of the equipment test pressure, the installation of a check valve is acceptable: in these cases, consideration should be given to adding auxiliary devices to minimize the possibility of backflow. The auxiliary device may be a non-return valve, a power-operated check valve, another ordinary check valve or similar device. It is not usually recommended to install a hydraulic relief device on the suction line of the pump that can withstand the maximum flow rate caused by a check valve failure, because the flow through the rotating machinery can generate centrifugal forces sufficient to damage the mechanical equipment. 2.3.5 Utility System Failure
The possible consequences of any utility system failure, whether involving the entire plant or a part of it, must be considered. It must be carefully analyzed and studied. Table 1 shows the common public systems that may fail and the parts of the equipment affected by them that may cause overpressure. 2.3.6 Failure of partial public systems
Analysis of the impact of overpressure caused by failure of partial public systems should include the chain reaction caused by overpressure and the overpressure response time involved. In the case of two devices working in parallel and with different power sources, if one of them fails during operation. It can be considered that the operation is not affected. In this case, the intact equipment can continue to operate. For example, a cooling water circulation system composed of two water pumps used in parallel and operated continuously, and the drive devices of these two water pumps have independent power sources. If one power source fails and the other fails.1 Overview
Pressure vessels, heat exchangers, operating equipment and piping are designed for the system pressures they are subjected to. The design is based on (a) the normal operating pressure at the operating temperature; (b) the effect of any combination of mechanical loads that may occur and the effect of different operating pressure differences; (c) the set pressure of the pressure relief device. The system designer must determine the minimum relief volume to prevent the pressure in the equipment from exceeding the maximum allowable accumulated pressure. The main causes of overpressure listed in 2.3.2 to 2.3.16 of this chapter can be used as a guide for the development of generally acceptable safety measures. 2.3.2 Vessel outlet closure
When the device is in operation, if the shut-off valve of a pressure vessel recess is mistakenly closed, the pressure in the vessel may exceed the maximum allowable working pressure. If the outlet shut-off valve is closed, overpressure may occur. Unless the management procedure controls the closure of the valve, such as installing a locking device or a lock, a pressure relief device needs to be installed. Each control valve port should be considered for abnormal operation. Generally, the block valve is omitted on the series vessel to simplify the pressure relief requirements. For system capacity design, it can be assumed that the control valve always operates in the normal operating position, the valve is normally open, can function in the event of a fault and is not affected by the main fault cause. For additional information, see 3.10.4. 2.3.3 Inadvertent opening of valves
Inadvertent opening of valves connected to high pressure sources such as high pressure steam or high pressure process fluid should be considered. Unless these valves are locked or locked in the closed position by a lock, the plan requires the installation of pressure relief devices to control the amount of discharge. 2.3.4 Check valve failure
The failure of the check valve to close properly must also be considered. For example, if the fluid is contained in the process system containing gas or vapor and the design repulsion pressure exceeds the design pressure of the upstream equipment by a large margin, after the process is stopped, the failure of the check valve will cause liquid backflow. When high pressure fluid flows back into the pump suction system, serious overpressure may result. It is acceptable to install a check valve as long as there is no potential for the backflow of high pressure fluid in excess of the equipment test pressure: in these cases, consideration should be given to adding auxiliary devices to minimize the possibility of backflow. The auxiliary device may be a non-return valve, a power-operated check valve, another ordinary check valve or similar device. It is not usually recommended to install a hydraulic relief device in the suction line that can withstand the maximum flow rate caused by the failure of the check valve, because the flow through the rotating machinery can generate centrifugal forces sufficient to damage the mechanical equipment. 2,3.5 Utility System Failure
The possible consequences of the failure of any utility system, whether involving the entire plant or a part of the plant, must be known. It must be carefully analyzed and studied. Table 1 shows the common public systems that may fail and the parts of the equipment affected by them that may cause overpressure. 2.3.6 Failure of partial public systems
Analysis of the impact of overpressure caused by failure of partial public systems should include the chain reaction caused by overpressure and the overpressure response time involved. In the case of two devices working in parallel and with different power sources, if one of them fails during operation. It can be considered that the operation is not affected. In this case, the intact equipment can continue to operate. For example, a cooling water circulation system composed of two water pumps used in parallel and operated continuously, and the drive devices of these two water pumps have independent power sources. If one power source fails and the other fails.1 Overview
Pressure vessels, heat exchangers, operating equipment and piping are designed for the system pressures they are subjected to. The design is based on (a) the normal operating pressure at the operating temperature; (b) the effect of any combination of mechanical loads that may occur and the effect of different operating pressure differences; (c) the set pressure of the pressure relief device. The system designer must determine the minimum relief volume to prevent the pressure in the equipment from exceeding the maximum allowable accumulated pressure. The main causes of overpressure listed in 2.3.2 to 2.3.16 of this chapter can be used as a guide for the development of generally acceptable safety measures. 2.3.2 Vessel outlet closure
When the device is in operation, if the shut-off valve of a pressure vessel recess is mistakenly closed, the pressure in the vessel may exceed the maximum allowable working pressure. If the outlet shut-off valve is closed, overpressure may occur. Unless the management procedure controls the closure of the valve, such as installing a locking device or a lock, a pressure relief device needs to be installed. Each control valve port should be considered for abnormal operation. Generally, the block valve is omitted on the series vessel to simplify the pressure relief requirements. For system capacity design, it can be assumed that the control valve always operates in the normal operating position, the valve is normally open, can function in the event of a fault and is not affected by the main fault cause. For additional information, see 3.10.4. 2.3.3 Inadvertent opening of valves
Inadvertent opening of valves connected to high pressure sources such as high pressure steam or high pressure process fluid should be considered. Unless these valves are locked or locked in the closed position by a lock, the plan requires the installation of pressure relief devices to control the amount of discharge. 2.3.4 Check valve failure
The failure of the check valve to close properly must also be considered. For example, if the fluid is contained in the process system containing gas or vapor and the design repulsion pressure exceeds the design pressure of the upstream equipment by a large margin, after the process is stopped, the failure of the check valve will cause liquid backflow. When high pressure fluid flows back into the pump suction system, serious overpressure may result. It is acceptable to install a check valve as long as there is no potential for the backflow of high pressure fluid in excess of the equipment test pressure: in these cases, consideration should be given to adding auxiliary devices to minimize the possibility of backflow. The auxiliary device may be a non-return valve, a power-operated check valve, another ordinary check valve or similar device. It is not usually recommended to install a hydraulic relief device in the suction line that can withstand the maximum flow rate caused by the failure of the check valve, because the flow through the rotating machinery can generate centrifugal forces sufficient to damage the mechanical equipment. 2,3.5 Utility System Failure
The possible consequences of the failure of any utility system, whether involving the entire plant or a part of the plant, must be known. It must be carefully analyzed and studied. Table 1 shows the common public systems that may fail and the parts of the equipment affected by them that may cause overpressure. 2.3.6 Failure of partial public systems
Analysis of the impact of overpressure caused by failure of partial public systems should include the chain reaction caused by overpressure and the overpressure response time involved. In the case of two devices working in parallel and with different power sources, if one of them fails during operation. It can be considered that the operation is not affected. In this case, the intact equipment can continue to operate. For example, a cooling water circulation system composed of two water pumps used in parallel and operated continuously, and the drive devices of these two water pumps have independent power sources. If one power source fails and the other fails.
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