Safety distance analysis of dimethylether filling stations using a modified individual risk assessment method

The physical properties of dimethylether (DME) are similar to conventional fuels such as LPG and diesel, so DME has been recently considered one of the most promising candidates for a substitute for them. Equipment failures in gas stations lead to accidents that pose significant threats to people and property. Therefore, prior to commercialization, safety standards for DME need to be developed based on risk analysis. In this study, we focused on safety distance in DME filling stations. A hypothetical DME filling station was modeled based on a DME-LPG mixed filling station designed by KOGAS, and safety distances were suggested from a semi-quantitative risk estimation approach using individual risk calculations. Modified individual risk calculations were performed with consequence analysis and failure mode under varying accident scenarios. Compared with existing individual risk analysis, the modified-individual risk approach is supplemented with a weighting factor to graduate each accident scenario by historical analysis. Subsequently, the outcome shows the individual risk that suggests a safety distance. To compare with conventional fuel, we also performed a comparative study on the filling station fuels LPG and DME. According to the quantitative risk estimation results, we propose a separation distance based on accident scenarios for each facility. In conclusion, safe distances for DME facilities are lower than those that dispense LPG. Therefore, a DME filling unit can be placed at conventional gas stations without increasing the safety distance. The results will also be useful in determining the standard for safety management of renewable and sustainable energy.     

Experimental and numerical analysis of fire scenarios involving two mechanically ventilated compartments connected together with a horizontal vent

This work deals with an experimental and numerical investigation of a fire scenario involving two rooms mechanically ventilated and connected together with a horizontal vent. The objective is to improve the understanding of the physical phenomena and to assess the capability of computational fluid dynamics (CFD) numerical simulations to predict flow field for such a fire scenario. The study is based on a set of large‐scale fire experiments performed in the framework of the OECD PRISME‐2 project in the DIVA multi‐room facility of the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) and of numerical simulations performed with the ISIS CFD code. The fire scenario consists of two rooms, one above the other, mechanically ventilated and connected to each other with a horizontal vent of 1 m². The fire is a heptane pool fire located in the lower room. The analysis focuses on the coupling between the burning rate, the flow at the vent, and the configuration of the mechanical ventilation. Several regimes of combustion are encountered from well‐ventilated steady fire to under‐ventilated unsteady and oscillatory fire. The results show that the burning rate is controlled by both the mechanical ventilation and the downward flow from the vent. The numerical simulations highlight the specific pattern of the oxygen concentration field induced by the downward flow at the vent.     

液态烃球罐区不动火安装消防水喷淋设施设计及施工技术

介绍了液态烃罐区消防水喷淋设施采用法兰、丝扣等不动火连接设计,重点论述了该设施的施工技术要求,为现有液态烃罐区的消防提供了安全保障,达到了满足防火规范要求的目的.     

Experimental determination of fire heat release rate with OC and CDG calorimetry for ventilated compartments fire scenario

This research deals with the experimental determination of the heat release rate (HRR) of fires in mechanically ventilated compartments based on oxygen consumption (OC) and carbon dioxide generation (CDG) calorimetry. It proposes formulations for fire in force‐ventilated compartments on the same basis as the relations established for hood calorimetry in an open atmosphere but considering inertia and unsteady behavior of the fire via the time variation mass of O₂ and CO₂ in the compartment. The value of the new formulations of HRR has been tested in two series of propane gas fire experiments performed in a large‐scale facility. The first series involves a fire scenario with one compartment, and the second series, a fire scenario with three compartments connected to each other by doorways. In the first test series, the OC and CDG formulations for HRR are assessed. In the second test series, the OC and CDG formulations are presented with two approaches to definition of the control volume: approach involving three rooms and the flow rate in the ventilation network and approach involving only the fire room and the flow rate through the doorways. On the basis of the fire experiments considered, the most accurate method (accuracy to within 10%) for determining the HRR is the CDG formulation with approach for the control volume without considering the flow rates at the doorways. This analysis points out the different features of each method (OC and CDG) and thoroughly discusses their advantages and drawbacks. The overall analysis allows guidelines to be formulated for fire HRR calculation in confined and ventilated compartments. Copyright © 2013 John Wiley & Sons, Ltd.     

Assessment of fire protection performance of water mist applied in exhaust ducts for semiconductor fabrication process

Fume exhaust pipes used in semiconductor facilities underwent a series of fire tests to evaluate the performance of a water mist system. The parameters considered were the amount of water that the mist nozzles used, the air flow velocity, the fire intensity and the water mist system operating pressure. In order to make a performance comparison, tests were also performed with a standard sprinkler system. The base case served as a reference and applied a single water mist nozzle (100 bar operating pressure, 7.3 l/min water volume flux and 200 µm mean droplet size) installed in the pipe (60 cm in diameter) subjected to a 350°C air flow with an average velocity of 2 m/s. In such a case, the temperature in the hot flow dropped sharply as the water mist nozzle was activated and reached a 60°C saturation point. Under the same operating conditions, four mist nozzles were applied, and made no further contribution to reducing the fire temperature compared with the case using only a single nozzle. Similar fire protection performances to that in the base case were still retained when the exhaust flow velocity increased to 3 m/s and the inlet air temperature was increased to 500°C due to a stronger input fire scenario, respectively. Changing to a water mist system produced a better performance than a standard sprinkler. With regard to the effect of operating pressure of water mist system, a higher operating pressure can have a better performance. The results above indicate that the droplet size in a water‐related fire protection system plays a critical role. Copyright © 2005 John Wiley & Sons, Ltd.     

LPG埋地储罐泄漏渗流扩散多相混合数值模型及模拟（Ⅰ）模型建立

在混合模型理论基础上,建立LPG（liquefied petroleum gas）在非饱和砂土中渗流扩散的传热、传质模型,研究LPG埋地储罐在砂土介质中发生泄漏时LPG渗流扩散的物理过程。该模型综合考虑了LPG泄漏相态、重力、黏滞力、毛细压力、扩散、非达西效应、气液相之间相互作用等影响因素的作用;在Forchheimer方程基础上,推导出多相混合流的非达西流动方程,并根据LPG实际渗流过程中流动状态的变化,将多相流非达西系数根据Reynolds数变化进行相应的改变,实现对多相流体从非达西流动向达西流动的转变现象的描述,能够模拟多种流动状态变化,扩展了模型的适用范围;根据LPG不溶于水的特性,简化了组分方程,推导出LPG体积浓度计算式。该模型能描述LPG埋地储罐泄漏后在砂土中流动趋势和对周围造成的影响,为埋地储罐场地选取、周边区域规划和事故预防、预测、应急提供依据。     

LPG埋地储罐泄漏渗流扩散多相混合数值模型及模拟（Ⅱ）数值模拟验证

采用本文（Ⅰ）报建立的LPG（liquefied petroleum gas）埋地储罐泄漏渗流扩散多相混合数值模型分别对气态和液态LPG在含水量不同的砂池中渗流扩散到外界环境的过程进行数值模拟,得到砂池中的流场、浓度场和LPG渗透到外界环境的质量流速。在数值模拟的基础上,对LPG气相、液相两种状态渗流扩散在砂池出口处LPG流速随时间的变化过程进行分析,总结出LPG渗透到外界的流速变化规律。模拟结果表明重力和出口位置对渗流扩散的方向影响很大,压力驱动是LPG渗流的重要影响因素;流体进出口处是流体流动活跃区域,非达西效应明显。数值模拟结果与LPG气体渗流扩散试验数据吻合较好,验证了理论模型和数值模拟的可靠性。     

液化气球罐泄露隐患控制方案研究与实施

液化石油气作为甲A类火灾危险性物质,极具挥发性、易燃易爆,液化气球罐由于超温、超压、液位失控、垫片损伤、材料破坏等原因造成的泄露,极易造成恶性重大事故。针对涠洲终端厂两台2 000 m3液化气球罐存在的安全风险,提出升级球罐安全附件、采用金属管刚性连接、及注水堵漏等措施,从根本上解决液化气球罐泄露问题。并结合涠洲终端厂实际情况,从管线、设备、流程方面研究分析,制定了合理的改造设计方案。     

Repeatability assessment of large‐scale fire experiment involving water spray system in a forced ventilated compartment

Repeatability of large‐scale fire test remains a key issue for code validation process. Most of the large‐scale experimental studies are based on single experiment, and the influence of repeatability is barely considered in the test analysis process. Due to the substantial cost, reproducing several trials of a given large‐scale fire scenario is not often performed. In the framework of the OECD PRISME 2 project, this topic has been identified, and a specific large‐scale fire test has been reproduced twice in the final goal of assessing the level of repeatability. The scenario is an oil pool fire in an enclosure mechanically ventilated and during which a water spray system is activated. The analysis consists in identifying a set of variables on which metrics is applied in order to quantify the levels of discrepancy between the two tests. A set of 27 variables are selected such as they characterize the whole fire scenario (the fire source, the gas phase, walls, the ventilation network, and the water spray system). The analysis points out that the repeatability levels are different depending on the type of variable. The gas temperature or species concentrations are more repeatable than gas pressure or air flow rate. In addition, a new methodology is proposed in comparing, for each physical variable, the variations due to repeatability (ie, the precision) and the uncertainty. A new metric is proposed helping modelers in code validation process.     

液化石油气罐区的危险性定量模拟评价技术及其事故预防

分析了液化石油气罐区的主要危险性及其特点 ,针对主要危险事故类型 :蒸气云爆炸 (UVCE)、沸腾液体扩展蒸气爆炸 (BLEVE)和池火灾 (PoolFire) ,利用灾害定量评价技术和数学模型对其危险性进行了定量模拟评价 ,确定了其火灾、爆炸事故的严重度、伤害范围等 ;并提出了相应的事故预防技术措施。     

Ionic liquid modified lignin-phenol-glyoxal resin: a green alternative resin for production of particleboards

The aim of this research was to evaluate the properties of particleboard panels bonded with ionic liquid treated lignin- phenol- glyoxal (LPG) resin. For this purpose, soda bagasse lignin was modified by 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) ionic liquid and then various contents of virgin and modified lignin (20, 30 and 40 wt% based on weight of phenol), phenol and glyoxal were used for synthesis of LPG resins. After resin synthesis, thermal and physicochemical properties of the synthesized resins such as curing behavior, gelation time, viscosity, solid content and density were measured. Finally, the resins so prepared were used for laboratory particleboard manufacturing. The panels physical (water absorption, thickness swelling) as well as mechanical (MOE, MOR and internal bond strength) properties were measured according to standard methods. The resins tests indicated that modification of lignin with ionic liquid not only can accelerate the gelation time and increase viscosity, density and solid content of LPG resins but also decrease the temperature required for curing the LPG resins. Based on the results of this work, the mechanical strength and dimensional stability of the particleboards bonded with a LPG resin can be improved by using modified lignin. The particleboards prepared with the LPG resin, using either modified or virgin lignin, presented higher water absorption as well as weaker mechanical strength than those prepared with the control PF resin. However, there does not appear to be any statistically significant difference between the some properties of the panels bonded with the control PF resin and those bonded with the LPG resin containing modified lignin.     

液氯槽车充装风险的防范

阐述了氯气的危害以及氯气泄漏应采取的一般防护措施;列举了氯气泄漏案例,重点介绍了河南神马氯碱发展有限责任公司防止液氯槽车充装时泄漏的具体方法和措施。     

液化石油气储罐在喷射火焰作用下的热响应模型

Abstract This paper describes a mathematical model developed to study the behavior of liquefied petroleum gas (LPG) tanks when subjected to jet fire. The model consists of a number of field and zone sub-models which are used to simulate the various physical phenomena taking place during the tank engulfment period. The model can be used to predict the pressure and temperature of the LPG in the tank, the temperature of the wall of tank, and the time of tank explosion. The comparisons between the model predicted results and the test data show good agreement. The results show that the jet fire partially impinging on tank wall led to higher wall temperature and the time to failure was shorter than that in engulfing pool fire. And the exposure of the upper wall in the vapor zone to the fire is more dangerous than that of the LPG contacted wall.     

过渡金属离子液相催化氧化烟气脱硫

烟气脱硫技术属我国环保市场急需的关键技术。过渡金属离子液相催化氧化烟气脱硫技术可以利用产生的稀硫酸制取石膏、肥料和聚合硫酸铁等多种高附加值的副产品。阐述了烟气脱硫的反应机理、脱硫吸收液和脱硫装置 ,以及吸收液酸度、温度、液气比、气速和入口浓度等因素对脱硫效率的影响。评述了金属离子的协同作用、各种工艺路线及副产物     

The Model of Thermal Response of Liquefied Petroleum Gas Tanks Partially Exposed to Jet Fire

This paper describes a mathematical model developed to study the behavior of liqupfied petroleum gas (LPG) tanks when subjected to jet fire. The model consists of a number of field and zone submodels which are used to simulate the various physical phenomena taking place during the tank engulfment period. The model can be used to predict the pressure and temperature of the LPG in the tank, the temperature of the wall of tank, and the time of tank explosion. The comparisons between the model predicted results and the test data show good agreement. The results show that the jet fire partially impinging on tank wall led to higher wall temperature and the time to failure was shorter than that in engulfing pool fire. And the exposure of the upper wall in the vapor zone to the fire is more dangerous than that of the LPG contacted wall.     

Optimal layout of additional facilities for minimization of domino effects based on worst-case scenarios

Accidents involving domino effects are more serious than other type of accidents. Although there have been studies on such accidents, it is still difficult to examine the actual factors and causes since the domino effect is influenced nonlinearly by factors involving flame, overpressure, and flying objects. We considered the case of adding new facilities to an existing system in a given site. The layout of new facilities suggests positions that minimize the domino effects, based on nonlinear optimization taking domino factors into account. We quantitatively calculated the domino risk of each facility through the concept of combined domino factors (flame, overpressure, and missile). Also, we identified variations of domino damage extent of the target system through comparison of the impacts of domino effect when additional facilities were installed. Simulated annealing was adopted for searching optimal positions. As a case study, we applied the proposed method to the case of adding DME storage tanks in the existing LPG charging facilities. The presented framework of the quantitative assessment of domino risk and safety standard for the layout of additional facilities would be useful for proper layout design for improved accident prevention.     

液化石油气储罐泄漏火灾爆炸事故后果模拟分析

液化石油气具有易燃、易爆、破坏力强的特点,在储存和使用过程中存在泄漏的危险。本文对液化石油气储罐泄漏后发生火灾爆炸模拟分析,并提出了一系列加强液化石油气储罐预防泄漏的对策措施,以确保液化石油气站的安全稳定运行。     

Thermodynamic,hydrodynamic, particle dynamic,and experimental analyses of silica nanoparticles synthesis in diffusion flame

Using silicon tetrachloride as a precursor, the silica nanoparticles (NPs) were synthesized in the diffusion flame of air and liquid petrol gas (LPG). Different effects on flame shape and temperature, silicon tetrachloride conversion, major gas‐phase compositions, and diameter of silica NPs were obtained via thermodynamic, hydrodynamic, or particle‐dynamic approaches. The size of silica NPs decreased with the increasing air‐flow rate, increased with the increasing LPG flow rate, and increased obviously with the increasing evaporator temperature. The size of the synthesized silica NPs is about 25–30 nm at an optimal condition.     

Study on fire smoke flow characteristics in the ventilation network and linkage control system in coal mines

In coal mining, smoke flow from tunnel fires can easily cause a large number of deaths in the ventilation network. But the optimal smoke flow path control methods and automatic control system were lacked. In order to improve the efficiency of fire emergency rescue, the control mechanism and regional linkage control system for fire induced smoke flow in ventilation network was studied. Based on a ventilation system in coal mines, different fire scenarios for smoke flow were analysed using ventilation simulation software (VSS). Smoke flow control methods were simulated under different ventilation modes, a contrastive analysis was conducted for the respective effects and the optimal smoke flow path control methods were confirmed in different fire scenarios. A new type of ventilation facility, regional monitoring sub-stations and remote linkage control platforms were developed for smoke control. A reliability evaluation model for the control system was established by Bayesian network. The failure of the linkage control is 98.9%, the monitoring sub-station is 64.4%, the sub-station communication is 43.9%; thus, a double insurance of the control process must be realised. Since its application, the proposed regional linkage control system has been repeatedly tested through fire drills, and good results have been obtained.     

华北C4液化气芳构化的研究

以华北C₄液化气和华北C₄液化气与中国石油兰州石化公司炼油厂FCC汽油为原料，采用小型固定流化床为芳构化反应装置，考察了反应温度和空速对华北C₄液化气芳构化产物收率、转化率、马达法辛烷值、研究法辛烷值、液体产品组成的影响规律和华北C₄液化气与中国石油兰州石化公司炼油厂FCC汽油的不同进料形式对芳构化反应的影响。实验结果表明，随反应温度的升高，干气、液化气和焦炭收率呈上升趋势，而汽油和柴油收率呈下降趋势，液体产物的马达法辛烷值和研究法辛烷值随反应温度的升高先增大后减小，当温度为430 ℃时，马达法辛烷值和研究法辛烷值存在最大值；随着空速的增加，干气和液化气的收率逐渐增加，而汽油、柴油和焦炭的收率呈缓慢下降的趋势；华北C4液化气的转化率均在97%以上，且随空速的升高而逐渐增加；液体产物的马达法辛烷值和研究法辛烷值随空速的升高先增加后减少，在空速（1～9） h^－1内存在最大值。华北C₄液化气芳构化实验室内的最佳操作条件：反应温度（430～450） ℃，空速（3～5） h^－1。对于华北C₄液化气与中国石油兰州石化公司炼油厂FCC汽油混炼而言，先通入汽油后通入液化气的汽油和柴油收率和液体中的芳烃含量明显高于液化气和汽油同时进料和先通入液化气后通入汽油。