基于修正突变级数法的天然气管道环境风险评价研究
发布时间：2018-07-25 20:00
【摘要】：管道运输具有安全、经济、节能和便捷等优势,已经成为天然气的主要运输方式,但由于天然气的易燃易爆性和燃气管道的突发性、群发性和复杂性特点,且暂未出台天然气类专项环境风险评价指南,构建全面系统、具有代表性的指标体系和选择合适的评价方法对天然气管道环境风险评价尤为重要。主要内容如下:(1)天然气管道风险源分为物质危险性和生产设备危险性,天然气属于易燃易爆气体,属于火灾危险甲级,其主要成分为窒息性气体甲烷;生产设施危险性主要涉及输气站场、截断阀室和管段的设备危险性。基于风险识别,构建天然气管道环境风险评价多级指标体系,以天然气管道环境风险为目标层,风险源、风险受体和环境风险防范措施为系统层,风险源危险指数、生态风险指数、自然环境风险指数、社会经济风险指数、环境风险防范措施指数为准则层,主要涉及的指标包括主要原料最大储存量与临界量之比、易燃易爆事故危险性、生物丰度指数、空气综合污染指数和事故应急预案等16个具体指标。(2)修正突变级数法是在考虑传统突变级数法的指标排序主观性的基础上,利用熵权法对其进行修正,通过计算指标熵权,在同一层级按熵权由大到小对指标进行排序,并根据控制变量的数量选择不同的突变模型计算隶属度。将修正突变级数法应用于安徽省江北产业集中区天然气管道支线工程,结果表明:该建设项目环境风险综合评价值为0.9221,属于Ⅳ级,存在环境风险;易燃易爆事故危险性、植被覆盖率、人口密度和环境监测预警系统是其主要限制因子。同时,以成熟的模糊综合法进行验证,两者结果基本一致,理论实践证明本方法可行,效果符合实际。修正突变级数法可作为反映系统突变的定量化方法,避免传统突变级数法在指标排序上的主观性。(3)将蒙特卡洛分析法应用于泄漏孔径、风速和温度3个参数,模拟天然气管道泄漏的污染物扩散,计算95%累计概率水平下甲烷最高容许接触浓度的半径,以此确定天然气管道突发事故风险环境防护距离,并耦合MATLAB进行研究,不仅使计算过程简洁明了,还可有效地解决风险评价中不确定性和随机性问题。以江北集中区天然气管道为例,95%累计概率水平下甲烷窒息阈值浓度(176825mg·m-3)和最高容许接触浓度(6700 mg·m-3)的半径分别为123.8 m和698.5 m,其环境防护距离设置可参考设为698.5 m,应将人群疏散到此范围外,减少天然气管道突发事故对人体的伤害。实践证明天然气管道的环境风险评价和确定环境防护距离可以为环境管理和突发事故应急处理提供参考价值。
[Abstract]:Pipeline transportation, which has the advantages of safety, economy, energy saving and convenience, has become the main transportation mode of natural gas. However, due to the flammable and explosive nature of natural gas and the sudden, mass and complex characteristics of gas pipeline, Moreover, it is very important for natural gas pipeline environmental risk assessment to establish a comprehensive system, a representative index system and a suitable evaluation method. The main contents are as follows: (1) the risk source of natural gas pipeline can be divided into material hazard and production equipment risk. Natural gas belongs to flammable and explosive gas, belongs to fire hazard class A, and its main component is asphyxiating gas methane; The risk of production facilities mainly involves the equipment danger of gas transmission station, cut-off valve chamber and pipe section. Based on risk identification, a multi-level index system of environmental risk assessment for natural gas pipeline is constructed. The target layer is environmental risk of natural gas pipeline, the risk source, risk receptor and environmental risk prevention measures are system layer, risk source risk index, and risk source risk index. The ecological risk index, natural environment risk index, social and economic risk index, environmental risk prevention measure index are the criterion layer. The main indexes involved include the ratio of the maximum storage capacity to the critical amount of main raw materials, the risk of flammable and explosive accidents. The biological abundance index, air pollution index and accident emergency plan are 16 specific indexes. (2) the modified catastrophe series method is based on the subjectivity of index ranking considering the traditional catastrophe series method, and the entropy weight method is used to modify it. By calculating the entropy weight of the index, the index is sorted according to the entropy weight from large to small at the same level, and the membership degree is calculated by selecting different catastrophe models according to the number of control variables. The modified catastrophe series method is applied to the natural gas pipeline branch project in the Jiangbei industrial concentration area of Anhui province. The results show that the comprehensive evaluation value of the environmental risk of the construction project is 0.9221, which belongs to grade 鈪，
本文编号：2144917
[Abstract]:Pipeline transportation, which has the advantages of safety, economy, energy saving and convenience, has become the main transportation mode of natural gas. However, due to the flammable and explosive nature of natural gas and the sudden, mass and complex characteristics of gas pipeline, Moreover, it is very important for natural gas pipeline environmental risk assessment to establish a comprehensive system, a representative index system and a suitable evaluation method. The main contents are as follows: (1) the risk source of natural gas pipeline can be divided into material hazard and production equipment risk. Natural gas belongs to flammable and explosive gas, belongs to fire hazard class A, and its main component is asphyxiating gas methane; The risk of production facilities mainly involves the equipment danger of gas transmission station, cut-off valve chamber and pipe section. Based on risk identification, a multi-level index system of environmental risk assessment for natural gas pipeline is constructed. The target layer is environmental risk of natural gas pipeline, the risk source, risk receptor and environmental risk prevention measures are system layer, risk source risk index, and risk source risk index. The ecological risk index, natural environment risk index, social and economic risk index, environmental risk prevention measure index are the criterion layer. The main indexes involved include the ratio of the maximum storage capacity to the critical amount of main raw materials, the risk of flammable and explosive accidents. The biological abundance index, air pollution index and accident emergency plan are 16 specific indexes. (2) the modified catastrophe series method is based on the subjectivity of index ranking considering the traditional catastrophe series method, and the entropy weight method is used to modify it. By calculating the entropy weight of the index, the index is sorted according to the entropy weight from large to small at the same level, and the membership degree is calculated by selecting different catastrophe models according to the number of control variables. The modified catastrophe series method is applied to the natural gas pipeline branch project in the Jiangbei industrial concentration area of Anhui province. The results show that the comprehensive evaluation value of the environmental risk of the construction project is 0.9221, which belongs to grade 鈪，
本文编号：2144917
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