聚乙烯醇装置的重大危险源辨识

聚乙烯醇是重要的化工原料,在其生产过程中存在大量重点监管的危险化学品及多种重点监管危险化工工艺。为了预防重特大事故的发生、降低事故损失、保护人民群众生命财产安全,对聚乙烯醇装置的重大危险源进行辨识及分级尤为重要。本文介绍了聚乙烯醇装置涉及的危险化学品及化工工艺,重点论述了聚乙烯醇装置的重大危险源的辨识、分级方法及其详细计算过程。     

基于三角模糊数的化工生产事故FTA模型

针对化工生产模糊系统,基于三角模糊数和事故树建立事故定量分析模型。运用该模型进行案例分析,确定储油罐体发生火灾爆炸事故的概率分布,得出基本事件的模糊重要度,明确该化工系统危险源分布的状态,指出导致事故发生的最危险路径,以上为企业管理人员制定安全措施提供重要的参考依据。     

黄磷氧化制五氧化二磷危险性分析与预防

黄磷氧化制五氧化二磷属危险化学品生产,生产过程中可能发生火灾、中毒和灼伤等生产事故。运用预先危险性分析法(PHA)对五氧化二磷生产过程的潜在危险性进行辨识,并对主要危险、有害因素进行分级、分类。根据辨识与分析结果,提出相应的措施,以提高企业安全生产管理水平,预防事故的发生。     

化工工艺设计危险辨识和安全控制

在全球每年都有各种化学品事故的发生,这些事故造成的影响、间接和直接损失不可估量,我国作为化学品生产的大国,在最近这些年经济的飞速发展过程中,开始对化工安全越发的重视,因此关于化工安全的学科也得到了迅速的发展。文章简要介绍了化工生产的特点,并对化工工艺设计中存在的危险源以及危险辨识方法进行了分析,提出了控制化工工艺设计中危险因素的对策,期望可以提供有用的借鉴。     

危险化学品灾害事故绿色化处置探讨

近年来，化工工业在国民经济和社会发展中的地位和作用日益突出，化工工业发展日趋迅速，但在化工工业快速发展的同时，危险化学品的种类、使用的频率和数量也不断增加，国内外危险化学品灾害事故发生的频率、规模也不断增大。危险化学品灾害事故不但容易直接导致人员伤亡、财产损失，且常有大量的有毒、有害物质排放到环境中，造成环境污染，导致新的人员伤亡、财产损失，造成事故二次损失。     

浅谈化工建设项目中的安全评价技术

化工建设项目存在许多危险有害因素,利用安全评价就技术对其进行危险有害因素的分析与辨识并制定对策措施,有助于降低事故的发生概率以及事故的严重程度。本文首先分析了安全评价对化工建设项目的必要性,接着重点对安全评价的主要内容进行了系统性分析,最后总结了相关的评价结论及建议。     

浅论化工企业危险有害因素辨识

化工行业安全事故多发,事故后果严重,是国家当前重点监管的高危行业。遏制事故发生的手段是进行风险分析及控制,危险、有害因素辨识又是进行风险分析及控制的首要步骤,因此全面、正确分析化工企业危险、有害因素十分重要。本文结合化工企业特点,依据国家有关安全法规、标准、书籍,运用危险、有害因素辨识原则及方法,对化工企业危险、有害因素辨识的内容、范围、注意点做出了较全面的探讨,将为化工企业危险源识别、风险分析及控制起到积极作用。     

浅析甲醇装置危险有害因素及事故应急对策

甲醇生产是一个复杂的、连续化的生产工艺过程,存在发生火灾、爆炸、泄漏、中毒等风险事故的可能性。通过对甲醇生产装置危险有害因素辨识及其危险有害程度的梳理,在甲醇装置事故后果分析的基础上,确定了该装置的事故应急对策,进而确保装置安全运行。     

基于HAZOP的空分装置危险性分析研究

空分装置是化工生产中的主要设备,因其独特的危险特点极易引发各类生产安全事故。HAZOP是一种典型的系统安全分析方法,尤其适用于化工工艺危险性分析过程中。本文采用HAZOP对空分装置中的空气压缩系统进行系统分析研究,辨识出其可能发生的故障、引发原因、可能导致的事故后果并提出了相应的安全对策措施及优化建议。     

连锁效应下化工装置定量风险分析初选方法

化工过程装置定量风险分析(QRA)首先面对装置初选的问题。基于2类危险源理论和装置连锁事故的主要诱因和过程机理分析,得出化工过程装置风险主要包括二方面:装置内危险物质的数量和危险特性,装置之间的事故连锁效应。提出与化工过程装置火灾、爆炸及毒物泄漏事故相对应的3类装置固有风险指标和2类装置事故连锁风险指标。基于2类风险指标分别建立装置专项事故风险综合评价矩阵,通过矩阵计算获得各装置专项事故综合风险的相对高低,并确立装置初选的最低条件,完成装置的初选,并通过实例应用演示了该方法。     

核电厂危险化学品使用及贮存设施设计

核电厂的运行和检修过程用到多种化学品,其中一部分属于危险化学品. 核电厂中,危险化学品安全与核安全不直接相关,但其危害可能会与核安全叠加,从而将危害放大,因此核电厂危险化学品的设计和管理非常重要. 以二代改进型的M310压水堆核电厂为例,结合多个机组的设计实践,对核电厂中的危险化学品进行分析,并对主要危险化学品贮存设施的设计和管理进行论述. 经辨识,核电厂贮存使用的危险化学品不属于重大危险源;贮存设施设计方案严格按照标准规范执行,结合核电厂的特点设计足够的安全措施,措施完备并满足危险化学品日益严格的监管要求,保证了核电厂内的危险化学品的安全.     

Closed-loop step response identification of integrating and unstable processes

Motivated by the fact that integrating and unstable processes are usually operated in a closed-loop manner for safety and economic reasons, this paper proposes a systematic closed-loop identification method based on step response test to facilitate closed-loop system operation and on-line optimization. To avoid jeopardizing the closed-loop system stability of such a process, guidelines are given for proper implementation of a closed-loop step test for model identification. By introducing a damping factor to the closed-loop step response for realization of the Laplace transform in frequency domain, a frequency response estimation algorithm is developed in terms of the closed-loop control structure used for identification. Accordingly, three model identification algorithms are derived analytically in frequency domain to obtain the widely used low-order process models of first-order-plus-dead-time (FOPDT) and second-order-plus-dead-time (SOPDT). To enhance fitting accuracy for a higher order process, in particular for a specified frequency range interested to control design and on-line tuning, a weighted least-squares fitting algorithm is also given based on the estimated process frequency response points. Illustrative examples from the recent literature are used to demonstrate the effectiveness and merits of the proposed identification algorithms.     

Modeling and control of Wiener-type processes

We develop a simple relay feedback method to identify Wiener-type nonlinear processes. It separates the identification problem of the nonlinear static function from that of the linear dynamic subsystem to simplify the identification procedure significantly. Owing to the separation, the unmeasurable output of the linear dynamic subsystem can be obtained in a straightforward manner. Then, determining the model structure of the nonlinear static function becomes very simple and the estimates are robust to additive output noises. We can identify the whole activated region of the nonlinear static function as well as the ultimate information of the linear dynamic subsystem from only one relay feedback test. More information on the linear dynamic subsystem can be estimated by well-established linear system identification methods from additional tests. We use a nonlinear control strategy to compensate the nonlinear dynamics of the Wiener process so that the design parameters can be determined by usual tuning rules developed for linear processes and a high control performance can be achievable as in linear processes.     

Operator training simulator process model implementation of a batch processing unit in a packaged simulation software

In chemical industry, especially in the case of continuous processes, operator training simulators (OTS) are becoming widely used. With the help of these systems several operation and safety issues can be analysed, and the operating staff of the plant can be trained for handling different plant failures. The main part of the OTS is the process model that replaces the real technology. Hence, in control development the simulated process variables are required to be reasonably accurate. The paper presents the structure of the process model of a batch processing unit in UniSim Design, different model constructions of a jacketed batch reactor and the identification of the parameters affecting its hydrodynamic and thermal behaviour. Construction of the process model is the first step in developing the OTS of the pilot plant located in the authors’ laboratory. It can be an effective tool in the development of model-based control systems.     

磷化氢环流熏蒸工艺

磷化氢环流熏蒸工艺主要是用于大型粮储工艺中,该工艺能最大限度地发挥磷化氢对害虫的毒性,可自动操作,对操作人员更安全,对环境影响小,值得推广使用。     

Consequence Identification for Maloperation in Batch Process

Batch processes are important in chemical industry, in which operators usually play a major role and hazards may arise by their inadvertent acts. In this paper, based on hazard and operability study and concept of qualitative simulation, an automatic method for adverse consequence identification for potential maloperation is proposed. The qualitative model for production process is expressed by a novel directed graph. Possible operation deviations from normal operating procedure are identified systematically by using a group of guidewords. The proposed algorithm is used for qualitative simulation of batch processes to identify the effects of maloperations. The method is illustrated with a simple batch process and a batch reaction process. The results show that batch processes can be simulated qualitatively and hazards can be identified for operating procedures including maloperations. After analysis for possible plant maloperations, some measures can be taken to avoid maloperations or reduce losses resulted from maloperations.     

间歇与半间歇反应热失控危险性评估方法

针对间歇、半间歇反应器中频繁更换物系和/或反应工艺,受时间和经济条件限制往往不可能对发生在其中的反应动力学进行深入研究的特点,建立适用于它们的热失控危险评估方法具有重要意义。本文对此做了简要的综述并且认为,尽管迄今还没有普适性的方法,但是对于某些类型的重要反应,安全界限图方法和反应失控情景分析方法还是较为适用的。前者虽然涉及参数较多,且没有考虑高温下物料二次分解的可能性,但能按照反应结果将量纲1操作参数平面划分为无积累、反应失控、未充分引发及无害4个子区域,从而可以先验地获取更多的信息;后者虽然忽略了均相与非均相反应的不同,但该方法可对一定工艺条件下目标反应失控和二次分解反应进行分析评估,简单易行,考虑更全面。     

Hazard analysis and critical control point of frying – safety assurance of fried foods

Deep frying can pose hazards due to oil deterioration (oxidation, polymerization, hydrolysis) and harmful components formation such as trans fatty acids, highly oxidized or polymerized constituents of fatty acids and acrylamide. An analysis of safety hazards of the production of the potato chips and french fries, was carried out from potato harvesting until final products packaging according to hazard analysis and critical control point approach focusing mainly on the first three principles. Since frying is considered a critical control point, the critical limits for the frying temperature and for the potential hazards must be controlled in order to ensure fried products safety.     

RSET/ASET,a flawed concept for fire safety assessment

For the evaluation of occupant safety in the case of building fires, the Required Safe Egress Time/Available Safe Egress Time (RSET/ASET) concept has become widespread and is now commonly used in the fire safety engineering profession. It has also become commonly used by smoke detector (smoke alarm) manufacturers in assessing whether a particular detector technology is adequate. It is shown in this paper that the concept is intrinsically flawed and its use promotes the diminishment of fire safety available to building occupants. The concept innately ignores the wide variations in capabilities and physical condition of persons involved in fire. It is based on implicitly assuming that, after a brief period where they assess the situation and mobilize themselves, occupants will proceed to the best exit in a robotic manner. This assumption completely fails to recognize that there are very few fires, especially in residential occupancies, where occupants perished or were seriously injured who had endeavored to exit in this robotic manner. Instead, in the vast majority of fire death and serious injury cases, the occupants did not move in such a manner and their evacuation took longer than anticipated on the basis of robotic movement. There is a wide variety of reasons for this, and these are well known in the profession. The concept also ignores that there can be a wide variation in fire scenarios. The same building and the same fire protection features can be evaluated, but both RSET and ASET can change drastically, depending on the scenario used. The consequence of using the RSET/ASET concept for fire safety engineering or product design purposes is that fire deaths and injuries are permitted to occur, which are preventable. Copyright © 2010 John Wiley & Sons, Ltd.