Quantitative division of gas protection area based on risk assessment of equivalent gas cloud explosion

doi:10.16085/j.issn.1000-6613.2018-0153

Abstract

Abstract:

To divide the prevention area of hazardous gas leakage, qualitative method is mainly used. But it is difficult to characterize specific scenes by qualitative method. It cannot be used to design and plan the risk prevention and control system. A method of dividing gas protection area quantitatively is proposed based on equivalent gas cloud theory and risk assessment of explosion accident. The equivalent gas cloud size and risk set of gas leakage dispersion can be obtained by Gaussian model and considering the on-site features such as gas leakage probability, wind speed and direction joint distribution probability and so on. Then the gas leakage scenes can be selected by according to risk grade. Aiming at the scenes with higher grade of dispersion risk, the ignition probability analysis is carried out. The multiplication method is used to calculate the influence range of gas cloud explosion. The risk set of the explosive consequences can be analyzed by using risk assessment of accidents. The quantitative division standards of gas protection area are determined by risk values for different device areas under the guidance of ALARP standard and scene coverage of fire & gas system (FGS) detector. Through one LNG receiving station case analysis, the protection area grade of different devices can be quantitatively obtained. Aiming at specific leak scenarios, the quantitative classification of gas protection zones can be achieved. The numerical calculation shows that the quantitative division of the gas protection area can provide theoretical support for the detector deployment of FGS.

Key words: hazardous gas, equivalent gas cloud, gas protection area, explosions, safety, quantitative classification

摘要：

目前对危险气体泄漏防护区域的划分方法主要为定性方法，难以对具体场景定量表征，进而无法用于风险防控系统的设计规划。本文在等价气云理论的基础上，基于爆炸事故后果风险评估，提出一种定量划分气体防护区域的方法。综合考虑气体泄漏概率、风速风向联合分布概率等现场特征要素，运用高斯扩散模型，得到气体泄漏扩散的等价气云体积以及气体泄漏扩散风险集合，并进行泄漏场景筛选。针对扩散风险较大的场景进行点火概率分析，利用多能法计算气云爆炸影响范围，对气云爆炸事故进行风险评估得到爆炸事故后果风险集合。在ALARP标准与火气系统探测器场景覆盖率的指导下，依据不同装置区域的风险值确定气体防护区域等级定量划分标准。通过某LNG接收站案例分析，可定量得到不同装置的防护区域等级，实现针对具体泄漏场景的气体防护区域等级定量划分。数值计算表明，气体防护区域定量划分可为火气系统探测器布设提供理论支持。

关键词: 危险气体, 等价气云, 气体防护区域, 爆炸, 安全, 定量等级划分

CLC Number:

X937

Xinge QI,Haiqing WANG,Yingshuai TIAN,Guoming CHEN. Quantitative division of gas protection area based on risk assessment of equivalent gas cloud explosion[J]. Chemical Industry and Engineering Progress, 2019, 38(03): 1587-1594.

齐心歌,王海清,田英帅,陈国明. 基于等价气云爆炸风险评估的气体防护区域定量划分[J]. 化工进展, 2019, 38(03): 1587-1594.

Figures/Tables 11

References 13

1	International Electrotechnical Commission . Explosive atmospheres-Part 0: Equipment - General requirements: IEC60079-0: 2017 [S]. 2017.
2	CROSTHWAITE P J , FITZPATRICH R D , HURST N W . Risk assessment for the siting of developments near liquefied petroleum gas installations[C]// IChemE Symposium Series No. 110, 1988.
3	Rijnmond Public Authority . A risk analysis of six potentially hazardous industrial objects in the rijnmond area-a pilot study [R]. Dordrecht: COVO, D. Reidel Publishing Co., 1982.
4	SPOUGE J . New generic leak frequencies for process equipment [J]. Process Safety Progress, 2010, 24(4): 249-257.
5	OZAY C , CELIKTAS M S . Statistical analysis of wind speed using two-parameter Weibull distribution in Alaçatı region [J]. Energy Conversion & Management, 2016, 121(8): 49-54.
6	HANSEN O R , GAVELLI F , DAVIS S G , et al . Equivalent cloud methods used for explosion risk and consequence studies [J]. Journal of Loss Prevention in the Process Industries, 2013, 26(3): 511-527.
7	齐心歌，王海清，宋贤生，等 . 基于控制室爆炸载荷的可燃气云等价尺寸阈值[J]. 化工学报，2017，68(12)： 4857-4864.
	QI X G , WANG H Q , SONG X S , et al . Threshold of equivalent gas cloud size based on explosion load of control room [J]. CIESC Journal, 2017, 68(12): 4857-4864.
8	DAYCOCK J H , REW P J . Development of a method for the determination of on-site ignition probabilities [M]. Epsom: UK HSE, 2004.
9	MOOSEMILLER M . Development of algorithms for predicting ignition probabilities and explosion frequencies [J]. Journal of Loss Prevention in the Process Industries, 2011, 24(3): 259-265.
10	BOSCH C J H , WETERINGS R A P M . Methods for the calculation of physical effects (Yellow Book) [M]. The Hague: Committee for the Prevention of Disasters, 2005.
11	ABRAHAMSEN E B , ABRAHAMSEN H B , MILAZZO M F , et al . Using the ALARP principle for safety management in the energy production sector of chemical industry [J]. Reliability Engineering & System Safety, 2018, 169(1): 160-165.
12	Instrument Society of America . Guidance on the evaluation of fire, combustible gas and toxic gas system effectiveness: ISA TR84.00.07-2010 [S]. 2010.
13	严龙，于芳，牟洪祥，等 . 石油化工企业火气系统安全性评估方法[J]. 火灾科学，2017，26(2)：122-126.
	YAN L , YU F , MOU H X, et al . Method of the evaluation of fire, combustible gas and toxic gas system effectiveness in petrochemical industry [J]. Fire Safety Science, 2017, 26(2): 122-126.

分类	孔径范围/mm
小孔泄漏	1～10
中孔泄漏	10～50
大孔泄漏	50～150
破裂	>150

分类	孔径范围/mm
小孔泄漏	1～10
中孔泄漏	10～50
大孔泄漏	50～150
破裂	>150

风险值	场景覆盖率/%	气体防护区域等级
>3×10^?3	>99	Ⅰ
3×10^?4～3×10^?3	95～99	Ⅱ
3×10^?5～3×10^?4	90～95	Ⅲ
3×10^?6～3×10^?5	80～90	Ⅳ
3×10^?6	60～80	Ⅴ

风险值	场景覆盖率/%	气体防护区域等级
>3×10^?3	>99	Ⅰ
3×10^?4～3×10^?3	95～99	Ⅱ
3×10^?5～3×10^?4	90～95	Ⅲ
3×10^?6～3×10^?5	80～90	Ⅳ
3×10^?6	60～80	Ⅴ

编号	设备	孔径
编号	设备	小孔泄漏1～10mm	中孔泄漏10～50mm	大孔泄漏50～150mm	破裂>150mm
	卸船系统
1	卸料臂	5.10×10^?4	4.31×10^?4	3.08×10^?4	1.04×10^?4
2	卸料管线	7.41×10^?4	6.87×10^?4	5.92×10^?4	3.65×10^?4
3	蒸发气回流臂	5.10×10^?4	4.31×10^?4	3.08×10^?4	1.04×10^?4
4	蒸发气回流管线	7.41×10^?4	6.87×10^?4	5.92×10^?4	3.65×10^?4
	储存系统
5	LNG储罐	5.10×10^?04	4.31×10^?04	3.08×10^?4	1.04×10^?4
6	低压输送泵	9.04×10^?6	8.81×10^?6	8.38×10^?6	7.11×10^?6
	再气化/外输系统
7	高压输送泵	1.80×10^?5	1.75×10^?5	1.66×10^?5	1.40×10^?5
8	开架式海水气化器	5.10×10^?6	4.31×10^?6	3.08×10^?6	1.04×10^?6
	蒸发气回收系统
9	蒸发气压缩机	8.88×10^?6	8.61×10^?6	8.12×10^?6	6.69×10^?6
10	分液罐	5.10×10^?6	4.31×10^?6	3.08×10^?6	1.04×10^?6
11	再冷凝器	5.10×10^?6	4.31×10^?6	3.08×10^?6	1.04×10^?6