标准编号:	SH/T 3210-2020
中文名称:	石油化工装置安全泄压设施工艺设计规范
英文名称:	Process design specification forpressure relieving devicesin petrochemical industry
行业分类:	SH    石油化工行业标准
发布机构:	中华人民共和国工业和信息化部
发布日期:	2020-08-31
实施日期:	2021-1-1
标准状态:	现行
翻译语言:	英文
文件格式:	PDF
中文字符数:	39000 字
翻译价格(元):	3500.00 元
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.



This Specification was prepared after repeated discussion and research by the preparing group according to the requirements of Notice on the Plan for the development and revision of the third batch of professional standards in 2017 (GONGXINTINGKE [2017] No.106) issued by the Ministry of Industry and Information Technology of the People's Republic of China, through extensive investigation, careful summarization of practical experience, reference to relevant domestic and international standards and extensive solicitation of opinions.



This Specification comprises 8 Clauses and 3 Annexes.



The main technical contents of this Specification are: basic requirements of pressure relieving devices, setting principles and requirements, requirements of set pressure and overpressure, analysis of overpressure operating conditions, calculation and selection of relief flowrate and relief area, etc.



China Petrochemical Corporation (SINOPEC) is in charge of the administration of this Specification, SINOPEC Technology Center Station of Technologic System Design is responsible for the daily management, and SINOPEC Engineering Incorporation is responsible for the explanation of the specific technical contents. In case of any opinion and suggestion in the process of implementing this standard, please send it to the daily management organization and the chief development organization.



This Specification was issued in 2020 for the first time.



Process design specification for pressure relieving devices in petrochemical industry



1 Scope



This Specification specifies the process design requirements for pressure relieving devices in petrochemical industry.



This Specification is applicable to the process design of pressure relieving devices in petrochemical industry, but not to the process design of pressure relieving devices in compressor chambers which are self-contained or as components in power boilers heated directly by flames, transportable pressure vessels and rotating or reciprocating-motion mechanical equipment.



2 Normative References



The following referenced documents are indispensable for the application of this Specification. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.



GB/T 150.1 Pressure vessels — Part 1: General requirements

GB/T 567.1 Bursting disc safety devices — Part 1: Basic requirement

GB/T 12241 Safety valves — General requirements

GB/T 12242 Performance test code — Pressure relief devices



3 Terms and Definitions



3.1 Terms and definitions



For the purposes of this document, the terms and definitions given in GB/T 12241, GB/T 12242, GB/T 567.1 and the following apply.



3.1.1

pressure relieving device

device designed to prevent the internal medium pressure from rising above a specified security value when the pressure system is in an emergency or abnormal condition



Note: The pressure relieving devices in this Specification are limited to safety valves and rupture disk devices. Other pressure relieving devices, such as breathing valve, buckling pin valve, breaking pin, fusible plug are not within the applicable range of this Specification.



3.1.2

safety valve

valve that uses the force of the medium itself to discharge a rated amount of fluid to prevent the pressure from exceeding a specified safety value When the pressure is reduced to a certain value, the valve closes automatically and prevents the medium from continuing to flow out. It is also known as pressure relief valve.



3.1.3

rupture disk device

non-reclosing pressure relieving device actuated by the static pressure difference between the inlet and outlet of the medium and designed to realize the pressure relieving function by the rupture of a pressure containing disk



3.1.4

set pressure

set opening pressure of pressure relieving device under use conditions, also known as level pressure



Note: The pressures not specified in this Specification are all gauge pressures.



3.1.5

back pressure

pressure at the outlet of pressure relieving device and is the sum of the built-up back pressure and the superimposed back pressure, also known as backpressure



3.1.6

built-up back pressure

pressure formed at the outlet of the pressure relieving device due to the medium flowing through the discharge system when the pressure relieving device is discharged



3.1.7

superimposed back pressure

static pressure that exists at the outlet of the pressure relieving device before it is about to operate, caused by other pressure sources in the discharge system



3.1.8

overpressure

pressure increment in excess of the set pressure of the pressure relieving device, usually expressed as a percentage of the set pressure



3.1.9

relieving pressure

set pressure plus overpressure, also known as relieving pressure



3.2 Main symbols



For the purposes of this specification, the following major symbols apply.



A——the heated surface area of the container;

Cp——the liquid specific heat capacity at constant pressure;



Cv—— the average specific heat at constant volume of gas at the relieving and operating temperatures;



D——the diameter of the container;



d——the inner diameter of feed pipe of gas storage tank;



F——the relieving reduction coefficient;



G——the relative density of liquid;



GL—— the liquid relief flowrate;



h——the wetting height of the container, which refers to the distance from the lower tangent line of the tank to the highest liquid level;



L——the total length of the container;



M——the molecular weight of the fluid;



Pd——the relieving pressure (absolute pressure);



Pn——the operating pressure (absolute pressure);



Ps——the set pressure;



Q——the maximum heat capacity of the system;



r——the latent heat of vaporization of the liquid under the relieving pressure;



T1——the relieving temperature;



Tn——the operating temperature;



TW——the wall temperature of equipment under fire condition;



t——the saturated temperature of relieving liquid under the pressure relief condition;



W——the relief flowrate of pressure relieving device;



WG——the relief flowrate of gas storage tanks of pressure relieving device;

ΔT——the temperature difference between the relieving temperature and operating temperature;

δ——the insulation thickness;



λ——the heat conductivity coefficient of thermal insulation material at room temperature;



ρ——the density;



ρG——the gas density under relieving pressure Pd;



v——the flow rate in the feed pipe of gas storage tank;



ω——the volume expansion coefficient, which refers to the volume expansion of liquid for every 1°C increase.



4 Basic rules



4.1 The pressure relieving devices shall be set up in accordance with the requirements of the pressure system under abnormal conditions to determine the overpressure analysis:



4.2 The independent pressure system of the pressure relieving devices shall be able to meet the system's relief requirements.



Note: Independent pressure system refers to the system separated from other systems with isolating devices. When a pressure system consisting of multiple containers is provided with shut-off devices (such as shut-off valves and control valves, or although there is a pipeline connection, the pipeline is not enough to relieve pressure), it is necessary to divide the pressure system into several independent pressure systems according to the position of the shut-off devices, and each independent pressure system is provided with pressure relieving devices.



4.3 When the system design pressure of the independent pressure system is greater than or equal to the highest possible pressure under the working conditions, the independent pressure system may not set up pressure relieving devices.



4.4 In addition to the reliability of protective instrument system reaches the reliability of pressure relieving device or the pressure relieving device cannot be used, the automatic interlock system, automatic shutdown system and other conventional instrument systems with anti-overpressure function shall not replace the protective effect of pressure relieving device on pressure system.



4.5 The setting of pressure relieving devices shall meet the requirements of its inspection cycle.



4.6 If the medium is viscous, strong corrosive or the toxicity degree is highly harmful or above, the auxiliary safety valve should be set up, and the auxiliary safety valve shall be of the same specification as the safety valve in use.



4.7 The inlet and outlet shut-off valves of safety valves in use shall remain opened then locked or car seal open; the inlet shut-off valve of auxiliary safety valves shall be closed then locked or sealed, and the outlet shut-off valve should be opened then locked or car seal open.



5 Principles and requirements of safety relief device setting



5.1 Setting principles



5.1.1 The safety valves shall be provided in the following situations:



a) The design pressure of the system is less than the pressure at the pressure source;



b) Except that the equipment itself has a safety valve and its set pressure and relieving capacity meet the relieving requirements of the system, the outlet of each section of reciprocating compressor or the outlet of positive displacement pump such as electric reciprocating pump, gear pump and screw pump shall be equipped with safety valves;



c) The system is connected with the outlet of blower, centrifugal compressor, centrifugal pump or steam reciprocating pump, and the design pressure of the system is less than its maximum outlet pressure;



d) The medium of the system expands or vaporizes when heated, and the system pressure may exceed the system design pressure.



5.1.2 The rupture disk device should be set separately in the following situations:



a) The system pressure increases rapidly, and the opening of the safety valve cannot meet the requirements of fast response time;



b) The safety relief flowrate required by the system is large, and the selection of safety valves is difficult;



c) The operating pressure of the system is very low or high, and the safety valve is difficult to manufacture;



d) The temperature during the safety relief of the system is low, and the operating characteristics of the safety valve may be affected when the process medium is relieved;



e) For the disposable pipeline system, the rupture of rupture disk device will not affect the operation and production.



5.1.3 The combination of safety valves and rupture disk devices should be set up in the following situations:



a) Under vacuum condition, no gas or air outside the system is allowed to enter the system through pressure relieving devices;



b) The system does not allow the process medium to leak through the safety valve during normal operation;



c) Long-term contact between the relief medium and the safety valve may lead to failure of the safety valve in the system;



d) The process medium is corrosive, so it is necessary to use corrosion-resistant materials or lined with anti-corrosion materials, and the safety valve has a high manufacturing cost;



e) The system has multiple and complicated overpressure conditions.



5.1.4 The setting of rupture disk devices shall meet the following principles:



a) Rupture disk devices should not be set for systems with frequent overpressure;



b) Rupture disk devices are not suitable for systems with large temperature fluctuations;



c) Apart from having a follow-up treatment system and meeting the requirements of safety and environmental protection, rupture disk devices shall not be used alone in places where the discharged medium is liquefied petroleum gas or explosive, or of extreme toxicity or high hazard.



5.2 Setting requirements



5.2.1 When the safety valve and rupture disk device are used in combination, the combined relief flowrate shall not be less than the safety relief flowrate of the protection system.



5.2.2 Safety valves and rupture disk devices used in series shall meet the following requirements:



a) There shall be measures to detect rupture or leakage of rupture disk devices between rupture disk device and safety valve.



b) When the rupture disk device is connected in series on the inlet side of the safety valve:



1) The marked bursting pressure of rupture disk device should not be greater than the set pressure of safety valve.



2) The nominal diameter of rupture disk device shall not be less than the nominal diameter of the inlet flange of the safety valve.



c) The rupture of rupture disk device shall not affect the normal operation of safety valve.



d) When the rupture disk device is connected in series on the outlet side of the safety valve, it shall ensure that the safety valve can be opened at the set pressure.



5.2.3 When rupture disk devices are used in series, there shall be measures to detect rupture or leakage between the two rupture disk devices.



5.2.4 When the safety valve and rupture disk device are used in parallel, the marked bursting pressure of rupture disk device shall not exceed 1.05 times the design pressure of the system.



5.3 Installation requirements



5.3.1 Safety valves shall meet the following installation requirements:



a) The safety valve shall be set on the part of the protection system which is easy to install, inspect and maintain.



b) The safety valve shall be set near the pressure source. When it is used in gas medium, it shall be set in the gas-phase space (including the gas-phase space above the liquid) or the pipeline connected to this space.



c) The flow sectional area of all pipes, valves and pipe fittings between the safety valve and the pressure source shall be greater than or equal to the inlet sectional area of the safety valve, and the connecting pipe shall be short and straight. When two or more safety valves are installed on one connector, the sectional area of the connector inlet shall be greater than or equal to the sum of the sectional areas of the inlets of these safety valves, excluding the auxiliary safety valves.



d) The nominal diameter of safety valve inlet pipe shall not be smaller than that of safety valve inlet flange, and the nominal diameter of safety valve outlet pipe shall not be smaller than that of safety valve outlet flange.



5.3.2 The rupture disk devices shall meet the following installation requirements:



a) The inlet pipe of rupture disk devices shall be short and straight, and the pipe diameter shall not be less than the nominal diameter of rupture disk devices.

b) Shut-off valves should not be set on the inlet pipeline of rupture disk devices. When the process requires a shut-off valve, the shut-off valve shall be opened then locked or car seal open, and the circulation area of the shut-off valve shall not be smaller than the relief area of rupture disk device.



6 Rules for set pressure and overpressure



6.1 When an independent pressure system is provided with a single safety valve, the set pressure of the safety valve shall not be greater than the design pressure of the protection system.



6.2 The percentage of set pressure and maximum overpressure of safety valve shall not exceed the values in Table 6.2.



Table 6.2 Percentages of set pressure and maximum overpressure of safety valves (in %)

Item Single safety valve Multiple safety valves

Ratio of set pressure of safety valve to design pressure of protection system Maximum overpressure percentagea Ratio of set pressure of safety valve to design pressure of protection system Maximum overpressure percentagea

Non-fire Primary valve 100 10Note 1 100 16Note 2

Other valves — — 105 16Note 2

Fire Primary valve 100 21 100 21

Other valves — — 105 21

Note 1: The greater of 10% of design pressure or 20kPa.

Note 2: The greater of 16% of design pressure or 30kPa.

a Maximum overpressure percentage refers to the ratio of the maximum overpressure to the design pressure of the protection system.



6.3 The maximum marked bursting pressure of rupture disk devices shall not be greater than the design pressure of the protection system.

Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Basic rules
5 Principles and requirements of safety relief device setting
6 Rules for set pressure and overpressure
7 Case of overpressure and calculation of relief device
8 Selection
Annex A (Informative) Volume expansion coefficient of hydrocarbon liquid and water at 15.6°C
Annex B (Informative) Calculation of relieving flowrate and relief area in chemical reaction runaway (temper system)
Annex C (Informative) Calculation of relief area in gas-liquid two-phase relief
Explanation of wording in this Specification

石油化工装置安全泄压设施工艺设计规范
1 范围
本规范规定了石油化工装置安全泄压设施的工艺设计要求。
本规范适用于石油化工装置安全泄压设施的工艺设计，不适用于直接用火焰加热的动力锅炉、移动式压力容器、旋转或往复运动机械设备中自成整体或作为部件的受压器室的安全泄压设施的工艺设计。
2 规范性引用文件
下列文件对于本规范的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本规范。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本规范。
GB/T 150.1 压力容器 第1部分：通用要求
GB/T 567.1 爆破片安全装置 第1部分：基本要求
GB/T 12241 安全阀一般要求
GB/T 12242 压力释放装置性能试验规范
3 术语和符号
3.1 术语和定义
GB/T 12241、GB/T 12242和GB/T 567.1界定的以及下列术语和定义适用于本规范。
3.1.1
安全泄压设施 pressure relieving device
一种，用来在压力系统处于紧急或异常状况时防止其内部介质压力升高到超过规定安全值的设施。
注：本规范中的安全泄压设施限指安全阀和爆破片。其他安全泄压设施如呼吸阀、爆破针阀、折断销、易熔塞等不在本规范适用范围内。
3.1.2
安全阀 safety valve
利用介质本身的力来排出额定数量的流体，以防止压力超过规定安全值的阀门。当压力降低到一定值后，阀门自行关闭并阻止介质继续流出。也称压力泄放阀。
3.1.3
爆破片 rupture disk device
一种由介质进出口静压差驱动的非重闭式安全泄压设施，通过承压片的爆破实现泄压功能。
3.1.4
设定压力 set pressure
在使用条件下，设定的安全泄压设施开启压力，简称定压。
注：本规范中未特别指出的压力，均为表压。
3.1.5
背压力 back pressure
安全泄压设施出口处的压力，是排放背压力和附加背压力的总和，简称背压。
3.1.6
排放背压力 built-up back pressure
安全泄压设施排放时，由于介质流经排放系统在安全泄压设施出口处形成的压力。
3.1.7
附加背压力 superimposed back pressure
安全泄压设施即将动作前，在其出口处存在的静压力，是由其他压力源在排放系统中引起的。
3.1.8
超过压力 overpressure
超过安全泄压设施设定压力的压力增量，通常用设定压力的百分数表示。
3.1.9
泄放压力 relieving pressure
设定压力加超过压力。也称排放压力。
3.2 主要符号
下列主要符号适用于本规范。
A——容器受热表面积；
Cp——液体的比定压热容；
Cv——气体在泄放温度和操作温度时的平均比定容热容；
D——容器直径；
d——气体储罐进料管的内径；
F——泄放减低系数；
G——液体的相对密度；
GL——液体泄放量；
h——容器的湿润高度，指罐体下切线至最高液面的距离；
L——容器的总长；
M——流体的分子量；
Pd——泄放压力(绝压)；
Pn——操作压力(绝压)；
Ps——设定压力；
Q——系统的最大受热量；
r——泄放压力下液体的汽化潜热；
T1——泄放温度；
Tn——操作温度；
TW——火灾工况时设备的壁温；
t——泄压工况时泄放液体的饱和温度；
W——安全泄压设施的泄放量；
WG——气体储罐安全泄压设施的泄放量；
T——泄放温度和操作温度的温差；
δ——保温层厚度；
λ——常温下绝热材料的导热系数；
ρ——密度；
ρG——泄放压力Pd下的气体密度；
v——气体储罐进料管内的流速；
ω——体积膨胀系数，指液体每升高1℃的体积膨胀量。
4 基本规定
4.1 安全泄压设施的设置要求应根据压力系统在非正常条件下的超压分析确定。
4.2 独立的压力系统的安全泄压设施应能满足系统的泄放要求。
注：独立的压力系统，指用隔断装置与其他系统分开的系统。由多个容器组成的压力系统，当其中设有隔断装置时(如切断阀、调节阀等，或虽有管线连通，但管线不足以泄压)，需要根据隔断装置的位置分为几个独立的压力系统，每个独立的压力系统均设置安全泄压设施。
4.3 当独立的压力系统的系统设计压力大于或等于各工况条件下可能出现的最高压力时，该独立的压力系统可不设置安全泄压设施。
4.4 除保护性仪表系统的可靠性达到安全泄压设施的可靠性或不能使用安全泄压设施外，防超压功能的自动联锁系统、自动开停车系统和其他常规仪表系统等，不应代替安全泄压设施对压力系统的保护作用。
4.5 安全泄压设施的设置应满足其检验周期的要求。
4.6 介质为黏性、强腐蚀性或毒性程度为高度危害及以上的安全阀宜设置备用，备用安全阀应与在用安全阀相同规格。
4.7 在用安全阀进出口切断阀均应锁开或铅封开；备用安全阀进口切断阀应锁关或铅封关，出口切断阀宜锁开或铅封开。
5 设置原则和要求
5.1 设置原则
5.1.1 下列情况应设置安全阀：
a) 系统的设计压力小于压力来源处压力的系统；
b) 除设备本身已有安全阀且其定压、泄放能力满足系统泄放要求情形外，往复式压缩机的各段出口或电动往复泵、齿轮泵、螺杆泵等容积式泵的出口；
c) 与鼓风机、离心式压缩机、离心泵或蒸汽往复泵出口连接的系统，且系统的设计压力小于其最高出口压力；
d) 介质受热膨胀或汽化，系统压力可能超过系统设计压力的系统。
5.1.2 下列情况宜单独设置爆破片：
a) 系统压力快速增长，安全阀的开启不能满足快速反应时间要求；
b) 系统需要的安全泄放量大，安全阀选型困难；
c) 系统的操作压力很低或很高，安全阀制造困难；
d) 系统安全泄放时的温度较低，工艺介质泄放时可能导致安全阀的工作特性受到影响；
e) 一次性使用的管路系统，爆破片的破裂不影响操作和生产。
5.1.3 下列情况宜组合设置安全阀和爆破片：
a) 在真空工况下，不允许系统外部气体或空气通过安全泄压设施进入的系统；
b) 正常操作过程中不允许工艺介质通过安全阀泄漏的系统；
c) 泄放介质与安全阀长期接触可能导致安全阀失灵的系统；
d) 工艺介质有腐蚀性，需要采用耐腐蚀的材质或内衬防腐蚀材料，安全阀的制造成本较高的系统；
e) 有多个超压工况，且超压工况比较复杂的系统。
5.1.4 爆破片的设置应满足下列原则：
a) 经常超压的系统不宜设置爆破片；
b) 温度波动较大的系统不宜设置爆破片；
c) 除具有后续处理系统且满足安全和环保要求外，爆破片不应单独用于排放介质毒性程度为极度、高度危害或易爆及液化石油气等场合。
5.2 设置要求
5.2.1 安全阀和爆破片组合使用时，组合泄放量不应小于被保护系统的安全泄放量。
5.2.2 安全阀和爆破片串联使用时应符合下列要求：
a) 爆破片和安全阀之间应有检测爆破片破裂或泄漏的措施。
b) 爆破片串联在安全阀进口侧时：
1) 爆破片的最大标定爆破压力不宜大于安全阀的定压；
2) 爆破片的公称直径不应小于安全阀的进口法兰公称直径。
c) 爆破片破裂后不应影响安全阀的正常动作。
d) 爆破片串联在安全阀出口侧时，应保证安全阀能在设定压力下开启。
5.2.3 爆破片和爆破片串联使用时，两个爆破片之间应有检测爆破片破裂或泄漏的措施。
5.2.4 安全阀和爆破片并联使用时，爆破片的标定爆破压力不应超过1.05倍系统的设计压力。
5.3 安装要求
5.3.1 安全阀应满足下列安装要求：
a) 安全阀应设置在所保护系统上易于安装、检查、维护的部位。
b) 安全阀应设置在靠近压力源的位置。当用于气体介质时，应设置在气相空间(包括液体上方的气相空间)或与该空间相连通的管线上。
c) 安全阀和压力源之间的所有管道、阀门和管件的流通截面积应大于或等于安全阀的进口截面积，其接管应短而直。当一个连接口上装设2个或2个以上的安全阀时，该连接口入口的截面积应大于或等于这些安全阀进口截面积的总和，不包括备用安全阀。
d) 安全阀入口管道公称直径不应小于安全阀进口法兰公称直径，安全阀出口管道公称直径不应小于安全阀出口法兰公称直径。
5.3.2 爆破片应满足下列安装要求：
a) 爆破片的入口管道应短而直，管径不应小于爆破片的公称直径。
b) 爆破片入口管线上不宜设置切断阀。当工艺要求设置切断阀时，切断阀应锁开或铅封开，切断阀的流通面积不应小于爆破片的泄放面积。
6 定压和超压
6.1 独立的压力系统设置单个安全阀时，安全阀定压不应大于所保护系统的设计压力。
6.2 安全阀定压和最大超压百分数，不应超过表6.2中的数值。
表6.2 安全阀定压和最大超压百分数 单位为％
项目 单个安全阀 多个安全阀
安全阀定压与所保护系统设计压力之比 最大超压百分数a 安全阀定压与所保护系统设计压力之比 最大超压百分数a
非火灾 第一阀 100 10注1 100 16注2
其他阀 — — 105 16注2
火灾 第一阀 100 21 100 21
其他阀 — — 105 21
注1：设计压力的10％或20kPa中的较大值。
注2：设计压力的16％或30kPa中的较大值。
a 最大超压百分数，指最大超过压力与所保护系统设计压力的比值。
6.3 爆破片最大标定爆破压力，不应大于所保护系统的设计压力。
7 超压工况分析及计算
7.1 超压工况分析
7.1.1 系统超压工况分析及最小泄放量计算宜按表7.1.1进行。
7.1.2 两个或两个以上毫无关联的超压工况不宜考虑同时发生。
表7.1.1 系统超压工况及最小泄放量a
序号 条件 液体泄放 气体泄放
1 容器出口关闭 进入容器的最大液体量 进入容器的气体和水蒸气总量，加泄放条件b产生的蒸气量和水蒸气量
2 冷凝器供水中断 — 在泄放条件下，冷凝器的总凝气量
3 塔项回流中断 — 进入塔的气体和水蒸气总量，加泄放条件下产生的蒸气量，减侧线回流冷凝的蒸气量
4 侧线回流中断 — 泄放条件下进入和离开该侧线部位的蒸气量差值
5 吸收塔贫油中断 — —
6 不凝气积聚 — 在塔中，为泄放条件下冷凝器的总凝气量
在其他容器内，为进入容器的气体和水蒸气总量，加泄放条件下产生的蒸气量和水蒸气量
7 高挥发性物质进入热油：
a)水进入热油
b)轻质烃进入热油 — 对于塔，应采取保护措施，尽量避免
对于换热器，采用两倍单根换热管截面积计算换热管破裂时，挥发性物质进入低压侧所产生的蒸气量
8 储罐或缓冲罐溢出 最大液体进入量 —
9 自动控制故障：
a)进口调节阀和旁路
b)出口调节阀
c)故障保位阀
d)节流阀 — 应逐个对各种情况做分析
10 不正常的热量或蒸汽输入 — 过热产生的最大蒸气量，包括不凝气
11 换热器管破裂 按两倍单根换热管截面积计算进入低压侧液体量 按两倍单根换热管截面积计算进入低压侧气体或水蒸气量
12 内部爆炸 — 用常规安全泄压设施不能控制，应避免事故的发生
13 化学反应失控 — 根据工艺特点进行分析
14 液体热膨胀 见7.2.4条 —
15 外部明火 — 见7.2.2条
16 动力中断(水蒸气、电源或其他) — 应根据装置的特点确定动力中断的影响，按可能发生的最坏情况确定泄放量
分馏塔 — 按所有泵都停运，导致回流液和冷却水中断考虑
反应器 — 搅拌或搅动停止、急冷或抑制剂中断时，反应失控产生的蒸气量
空冷器 — 风扇停转时，正常和事故工况蒸气量之差
缓冲罐 — 进入罐的最大液体体积流量
a 表中列出的仅为工艺装置常见的单一超压工况。
b 泄放条件：指安全阀在最大超压时入口的温度和压力。
7.2 泄放量的计算
7.2.1 出口切断工况
a) 压缩机储气罐由于出口阀关闭造成超压时，安全泄压设施的泄放量宜按压缩机的最大生产能力计算。
b) 液体储罐由于出口阀关闭造成超压时，安全泄压设施的泄放量宜按泄放条件下进入储罐物料的最大流量计算。
c) 气体储罐由于出口阀关闭造成超压时，安全泄压设施的泄放量宜按式(7.2.1)计算。