Maintenance-related major accidents: Classification of causes and case study

The potential for major accidents is inherent in most industries that handle or store hazardous substances, for e.g. the hydrocarbon and chemical process industries. Several major accidents have been experienced over the past three decades. Flixborough Disaster (1974), Seveso Disaster (1976), Alexander Kielland Disaster (1980), Bhopal Gas Tragedy (1984), Sandoz Chemical Spill (1986), Piper Alpha Disaster (1988), Philips 66 Disaster (1989), Esso Longford Gas Explosion (1998), Texas City Refinery Explosion (2005), and most recently the Macondo Blowout (2010) are a few examples of accidents with devastating consequences.Causes are being exposed over time, but in recent years maintenance influence tends to be given less attention. However, given that some major accidents are maintenance-related, we intend to concentrate on classifying them to give a better insight into the underlying and contributing causes.High degree of technological and organizational complexity are attributes of these industries, and in order to control the risk, it is common to deploy multiple and independent safety barriers whose integrity cannot be maintained without adequate level of maintenance. However, maintenance may have a negative effect on barrier performance if the execution is incorrect, insufficient, delayed, or excessive. Maintenance can also be the triggering event.The objectives of this article are: (1) To investigate how maintenance impacts the occurrence of major accidents, and (2) To develop classification schemes for causes of maintenance-related major accidents.The paper builds primarily on model-based and empirical approaches, the latter being applied to reports on accident investigation and analysis. Based on this, the Work and Accident Process (WAP) classification scheme was proposed in the paper.     

An evaluation of risk assessment framework for industrial accidents in India

Due to rapid industrialization, with high population density and constraints of land, it is expected that level of risks arising from the hazardous industries will increase in India in the coming decades. However, 30 years after the Bhopal accident (1984), except a few discrete regulations, there is as yet no integrated system for assessing and managing risks arising out of these hazardous industries in India. The gravity of aspects related to the management of industrial risk still remains crucially important. In particular, there is no standard guideline on risk analysis methodology, acceptability or tolerability criteria, nor is there an accident database or a risk reduction strategy for the areas where risk levels are already high. On top of this, there are technical and legislative gaps in the institutional framework to implement any of the above mentioned issues. With the backdrop of the Bhopal gas tragedy, the objective of this paper is therefore to evaluate the effectiveness of a comprehensive risk assessment framework for the emerging economy of India, in order to control and/or to reduce the risk level that exists. In this context, regulations and policies pertaining to industrial risk assessment were reviewed.     

Thermal risk in batch reactors: Theoretical framework for runaway and accident

Thermal safety and risk of accidents are still challenging topics in the case of batch reactors carrying exothermic reactions. In the present paper, the authors develop an integrated framework focusing on defining the governing parameters for the thermal runaway and evaluating the subsequent risk of accident. A relevant set of criteria are identified in order to find the prior conditions for a thermal runaway: failure of the cooling system, critical temperature threshold, successive derivatives of the temperature (first and second namely) vs. time and no detection in due time (reaction time) of the runaway initiation. For illustrative purposes, the synthesis of peracetic acid (PAA) with hydrogen peroxide (HP) and acetic acid (AA) is considered as case study. The critical and threshold values for the runaway accident are identified for selected sets of input data. Under the conditional probability of prior cooling system failure, Monte Carlo simulations are performed in order to estimate the risk of thermal runaway accident in batch reactors. It becomes then possible to predict the ratio of reactors, within an industrial plant, potentially subject to thermal runaway accident.     

Prenuptial perfume: Alloanointing in the social rituals of the crested auklet (<Emphasis Type="Italic">Aethia cristatella</Emphasis>) and the transfer of arthropod deterrents

Alloanointing, the transfer of chemicals between conspecifics, is known among mammals, but hitherto, the behavior has not been documented for birds. The crested auklet (Aethia cristatella), a colonial seabird of Alaskan and Siberian waters, alloanoints during courtship with fragrant aldehydes that are released from specialized wick-like feathers located in the interscapular region. Crested auklets solicit anointment at the colony, and prospective mates rub bill, breast, head, and neck over wick feathers of their partners. This distributes aldehydes over the head, neck, and face where the birds cannot self-preen. The resulting chemical concentrations are sufficient to deter ectoparasites. Auklets that emit more odorant can transfer more defensive chemicals to mates and are thus more sexually attractive. Behavioral studies showed that crested auklets are attracted to their scent. Wild birds searched for dispensers that emitted their scent and rubbed their bills on the dispensers and engaged in vigorous anointment behaviors. In captive experiments, naïve crested auklets responded more strongly to synthetic auklet scent than controls, and the greatest behavioral response occurred during early courtship. This study extends scientific knowledge regarding functions of alloanointing. Alloanointing had previously been attributed to scent marking and individual recognition in vertebrates. Alloanointing is described here in the context of an adaptive social cue — the transfer of arthropod deterrents between prospective mates.     

Applications of resilience engineering principles in different fields with a focus on industrial systems: A literature review

This paper reviews literature that addresses applications of resilience engineering principles to various fields. Recently the concept has attracted great attention from a technical and industrial perspective. The primary focus of this paper is to review the resilience engineering applications to industrial systems with the purpose of applying them to the chemical industry. A systematic review is performed to classify peer-reviewed journal papers that are associated with resilience engineering applications into three categories: industrial systems, ecological systems, and interlinked systems. The literature in the category of industrial systems is further divided based on the type of approaches such as field studies, case studies, methodologies, and mathematical modeling. After thoroughly analyzing the literature, four key research areas are identified: Considering socio-technical factors for resilience assessment efficiently; Inculcating the possibility of multiple disasters in resilience assessment; Design optimization for resilience enhancement; Efficient restoration strategies. All these research areas have not been explored exclusively for chemical facilities to a great extent. It is concluded that if these research areas are addressed appropriately, it would help in triggering the research pertaining to the application of resilience engineering principles in chemical facilities.     

A chemical plant protection game incorporating bounded rational attackers and distribution-free uncertainties

The chemical industry has an important role in our modern society. Due to the existence of hazardous materials and possible extreme producing conditions, chemical facilities are also considered dangerous. Research has pointed out that a successful attack on chemical plants may cause mass casualties, in the United States. Game theory has been employed to improve the protection of chemical plants, and current literature on chemical plant protection games assume a ‘rational’ attacker. The present paper studies a game-theoretic model, which is played by a rational defender and a ‘bounded rational’ attacker, for improving chemical plant protection. The attacker modeled in this paper is assumed to play higher payoff strategies with higher probabilities, which is innovative from the current chemical security literature. Attackers in the current chemical plant protection games would always play the strategy with the highest payoff (probability of 100%). Distribution-free uncertainties on attacker's parameters are also integrated into the model. An algorithm for solving the game presented in this paper is also proposed. A case study reveals that although a bounded rational attacker would reduce the defender's expected payoff, the defender's equilibrium strategy from the present model is robust to different attacker behaviors.     

同位素稀释高分辨气相色谱-高分辨质谱法测定氯化石蜡工业品中二噁英

氯化石蜡（CPs）作为一种用途广泛、产量大的有机氯化学工业品,具有组成多样、基质复杂等特点,对其中产生的二噁英（PCDD/Fs）检测是当前工作面临的难题。建立了同位素稀释高分辨气相色谱-高分辨质谱法检测CPs工业品中PCDD/Fs的分析方法。对样品净化过程进行了优化,通过提取溶剂筛选,去除固体CPs中部分基质,建立的双活性炭柱法可高效去除CPs基质。方法采用¹³ C₁₂标记的PCDD/Fs内标物进行定性和定量分析。17种PCDD/Fs同系物的检出限为0.1～3 pg/g,回收率为31.7%～100%。该方法可对高纯度工业品中痕量持久性有机污染物进行高效的定性和定量分析,能够满足国家标准方法对PCDD/Fs检测的要求。     

重铬酸钾法测定化学需氧量的实验条件优化

以降低成本、减少二次污染、提供多元化实验条件为主要出发点,开展GB 11914-89中氯离子掩蔽剂加入量和催化剂种类等优化实验研究。结果表明:采用按比例加入的方式可以降低硫酸汞使用量,m[HgSO4]:m[Cl-]=10∶1即可达到有效掩蔽效果;在标准样品、地表水和一般废水的COD测定中,硫酸镍、硫酸铝钾和磷酸二氢锰作为硫酸银的替代物具有一定的可行性,建议最低加入量为4g/L。     

Estimation of terrestrial chemical spill risk factors using a modified Delphi approach

The large number of chemical spills each year in the United States presents a potentially significant risk to human health and the environment. In an effort to manage this risk, the authors are developing a screening tool to assess the immediate threat to human and environmental receptors from land-based chemical spills. As part of this development effort, a modified Delphi survey was employed to determine the most important factors governing this risk and the relative importance of these factors. Results of the survey indicate that accounting for the attributes of the spilled chemical as well as the characteristics of the surrounding environment is imperative in making informed decisions regarding spill planning and mitigation. Survey results further indicate the greatest concern during spill events to be the risk to human health, which must be considered directly as well as factored into decisions concerning the protection of environmental receptors.     

浅谈化工园区环境执法过程中存在的主要问题及对策

阐述了化工园区环境执法中存在的主要问题,并提出了相应的对策,即应健全环境法制建设,强化执法手段;实行垂直管理,建立统一监管机制;加大对环境保护的宣传教育力度,提高环境法制观念;加强环保执法队伍的建设;加强执法监督机制建设;加强奖惩机制建设。