【摘要】：管道運輸具有安全、經(jīng)濟、節(jié)能和便捷等優(yōu)勢,已經(jīng)成為天然氣的主要運輸方式,但由于天然氣的易燃易爆性和燃氣管道的突發(fā)性、群發(fā)性和復雜性特點,且暫未出臺天然氣類專項環(huán)境風險評價指南,構(gòu)建全面系統(tǒng)、具有代表性的指標體系和選擇合適的評價方法對天然氣管道環(huán)境風險評價尤為重要。主要內(nèi)容如下:(1)天然氣管道風險源分為物質(zhì)危險性和生產(chǎn)設備危險性,天然氣屬于易燃易爆氣體,屬于火災危險甲級,其主要成分為窒息性氣體甲烷;生產(chǎn)設施危險性主要涉及輸氣站場、截斷閥室和管段的設備危險性�；陲L險識別,構(gòu)建天然氣管道環(huán)境風險評價多級指標體系,以天然氣管道環(huán)境風險為目標層,風險源、風險受體和環(huán)境風險防范措施為系統(tǒng)層,風險源危險指數(shù)、生態(tài)風險指數(shù)、自然環(huán)境風險指數(shù)、社會經(jīng)濟風險指數(shù)、環(huán)境風險防范措施指數(shù)為準則層,主要涉及的指標包括主要原料最大儲存量與臨界量之比、易燃易爆事故危險性、生物豐度指數(shù)、空氣綜合污染指數(shù)和事故應急預案等16個具體指標。(2)修正突變級數(shù)法是在考慮傳統(tǒng)突變級數(shù)法的指標排序主觀性的基礎上,利用熵權法對其進行修正,通過計算指標熵權,在同一層級按熵權由大到小對指標進行排序,并根據(jù)控制變量的數(shù)量選擇不同的突變模型計算隸屬度。將修正突變級數(shù)法應用于安徽省江北產(chǎn)業(yè)集中區(qū)天然氣管道支線工程,結(jié)果表明:該建設項目環(huán)境風險綜合評價值為0.9221,屬于Ⅳ級,存在環(huán)境風險;易燃易爆事故危險性、植被覆蓋率、人口密度和環(huán)境監(jiān)測預警系統(tǒng)是其主要限制因子。同時,以成熟的模糊綜合法進行驗證,兩者結(jié)果基本一致,理論實踐證明本方法可行,效果符合實際。修正突變級數(shù)法可作為反映系統(tǒng)突變的定量化方法,避免傳統(tǒng)突變級數(shù)法在指標排序上的主觀性。(3)將蒙特卡洛分析法應用于泄漏孔徑、風速和溫度3個參數(shù),模擬天然氣管道泄漏的污染物擴散,計算95%累計概率水平下甲烷最高容許接觸濃度的半徑,以此確定天然氣管道突發(fā)事故風險環(huán)境防護距離,并耦合MATLAB進行研究,不僅使計算過程簡潔明了,還可有效地解決風險評價中不確定性和隨機性問題。以江北集中區(qū)天然氣管道為例,95%累計概率水平下甲烷窒息閾值濃度(176825mg·m-3)和最高容許接觸濃度(6700 mg·m-3)的半徑分別為123.8 m和698.5 m,其環(huán)境防護距離設置可參考設為698.5 m,應將人群疏散到此范圍外,減少天然氣管道突發(fā)事故對人體的傷害。實踐證明天然氣管道的環(huán)境風險評價和確定環(huán)境防護距離可以為環(huán)境管理和突發(fā)事故應急處理提供參考價值。
[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，

本文編號：2144917