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Deng H.-F.,China University of Petroleum - East China | Chen G.-M.,China University of Petroleum - East China | Zhu Y.,China University of Petroleum - East China | Fu J.-M.,China University of Petroleum - East China | Liu D.-X.,Petroleum Prospecting and Design Institute
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012

Aiming at the problem of gas leakage and dispersion in complex terrain, a CFD-based gas leakage and dispersion numerical simulation model in complex terrain was proposed. The gas distribution on the ground and variation of tracer gas concentration of monitoring points with time were estimated. The effects of terrain, wind direction and wind speed on gas dispersion were obtained. Taking SF 6 as tracer gas, a gas release experiment was carried out in mountain gas gathering station. The colored smoke generator was taken as a tool to determine the arrangement of the sampling points. The electronic time-controlled air sampler and gas chromatography-electron capture detection method were used for sample collection and sample analysis, respectively, which could measure the concentration of tracer gas in sampling points at different time. The results of SF 6 release experiment show that the experimental program is reasonable and has wide applicability. The model can effectively reduce the number of sampling points, improve the effectiveness of sampling data, and implement the test data acquisition and analysis. The contrast between simulation results and experiment results illustrates the validity of numerical model in handling gas leakage and dispersion in complex mountainous terrain. Source

Zhang B.,China University of Petroleum - East China | Chen G.-M.,China University of Petroleum - East China | Gong J.-H.,Petroleum Prospecting and Design Institute | Wang Y.,Petroleum Prospecting and Design Institute
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2010

The method of gas detection and alarm instrument networks optimization was presented. Then, a CFD model for natural gas leakage in a gas gathering station of a high sulfide gas field was set up and the gas detection and alarm instruments were set up as monitoring points. The methane and hydrogen sulfide volume fractions of monitoring points were recorded by the simulation of natural gas release and dispersion process. The sensitivity to high and low level placement of combustible gas detectors, validity and response time of both combustible and toxic gas detectors in large and small release rates were investigated. The results show that, for high-sulfide natural gas leakage, better detection can be achieved when combustible detectors are set higher and hydrogen sulfide detectors are more effective compare to combustible gas detectors. Therefore, the leakage detection system is recommended to be configured mainly with hydrogen sulfide detectors supplemented by combustible gas alarm detectors. Source

Zhu Y.,China University of Petroleum - East China | Chen G.,China University of Petroleum - East China | Liu D.,Petroleum Prospecting and Design Institute
Huagong Xuebao/CIESC Journal | Year: 2010

Massive release of sour gas and dispersion of fatal hydrogen sulfide brought about by gas sweetening unit leakage are a major threat to the safety of sour gas processing plant. By analyzing the leakage and atmospheric conditions, the scene of accident, caused by the leakiness of gas sweetening unit, were determined. Based on large eddy simulation of turbulent flows, H2S dispersion in complex terrain was simulated. The peak time for accident was estimated, hazard regions were ranked and the influences of terrain on dispersion could be summarized as spatial obstacle, channeling and aggregation. Dose-response relationship for acute H2S poisoning was used to assess the cumulative effects of H2S on the public and calculate the lethal percentages. The maximum distances, downwind deflection angles, maximum widths and areas of the lethal regions were obtained. The application in one sour gas processing plant in mountainous area shows that the accident will cause high death risk around the plant and adjacent road, and not lead to mortality in the nearby residential area and planned highway. Based on the features of the accident, recommendations to establishing emergency planning zone, taking immediate shelter and implementing priority relief are suggested for emergency response. © All Rights Reserved. Source

Wang X.-L.,China University of Petroleum - Beijing | Wang X.-L.,Petroleum Prospecting and Design Institute | Shuai J.,China University of Petroleum - Beijing | Zhang J.-Q.,Petroleum Prospecting and Design Institute
Yantu Lixue/Rock and Soil Mechanics | Year: 2011

Mining induced ground surface subsidence could result in pipeline bending in a large scale which has great threatening to pipeline safety. An analytical methodology for evaluating stress and strain distribution of buried pipeline crossing mining subsidence area is developed. Ground surface spatial deformation due to mining is predicted by using Probability function integration method. Deformation compatibility equation between pipeline physical elongation and pipeline geometrical elongation is derived taking care of axial pipe-soil friction and steel pipe material nonlinearity; and pipeline stress and strain are calculated with iterative solving method. With proposed method, stress and strain distribution of pipeline crossing mining subsidence area is investigated. The result shows that tensile and compressive deformations at different pipeline segments due to pipe-soil friction associates with pipeline spacial bending deformation. Results of proposed method are close to that of finite element method and it is approved to be competent for investigating the response of buried pipeline crossing mining subsidence with any angle. Finally, effects of mining, pipeline and backfill on pipeline deformation and stress are analyzed; and two simple equations for evaluating the maximum stress and strain of pipeline are developed. Source

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