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In order to study a new leak detection and location method for oil and natural gas pipelines based on acoustic waves, the propagation model is established and modified. Firstly, the propagation law in theory is obtained by analyzing the damping impact factors which cause the attenuation. Then, the dominant-energy frequency bands of leakage acoustic waves are obtained through experiments by wavelet transform analysis. Thirdly, the actual propagation model is modified by the correction factor based on the dominant-energy frequency bands. Then a new leak detection and location method is proposed based on the propagation law which is validated by the experiments for oil pipelines. Finally, the conclusions and the method are applied to the gas pipelines in experiments. The results indicate: the modified propagation model can be established by the experimental method; the new leak location method is effective and can be applied to both oil and gas pipelines and it has advantages over the traditional location method based on the velocity and the time difference. Conclusions can be drawn that the new leak detection and location method can effectively and accurately detect and locate the leakages in oil and natural gas pipelines. 相似文献
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赵云佩 《中国安全生产科学技术》2020,16(8):131-137
为了解决老母矿近距煤层的开采难题,通过理论分析并利用FLAC 3D数值模拟软件进行模拟,分析出煤层前后推进150 m是最合理的步距,侧向采动支撑压力在15~50 m内存在影响。基于这些理论数据,确定回采巷道的合理位置,进而确定以内错距离范围为30~60 m的内错式布置方式布置巷道和无煤柱协调开采布局,并进行井下工程应用。最后把无煤柱协调开采布局与双巷掘进开采布局对比,得出无煤柱协调开采布局的先进性和优势,研究结果可为同类条件下的工程应用提供借鉴。 相似文献
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从安全性和运营角度对油库选址的影响因素及评价指标分析对油库的安全稳定及有效运营具有重要的意义。该文选取与安全和运营有关的人口企业数量、安全管理能力、消防设施规划、地形地质条件、铁路公路数量、市场投资收益、政策支持情况等影响因子进行重要性及合理程度分析,综合运用安全度与运营格局影响因素多元耦合关系,构建了油库区安全与运营评价体系,改进了原有的模糊层次法评价模型,并对某油库区安全度与运营格局进行了评估验证。结果表明:利用改进模糊层次法能够较好地评价不同地址的优先级,评价模型具有一定应用性,能够对不同地址的特点及评价权重进行有效分析,可见油库选址优先级评价方法是实用且有效的。该研究方法及结果可以为油库区地址的优选提供一定参考与建议。 相似文献
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Toxic gas leakage in a tank area can have catastrophic consequences. Storage tank leakage location (particularly for high leakage) and downwind storage tanks potentially influence gas diffusion in tank areas. In this study, we developed a numerical and experimental method to investigate the impact of a high leakage location and downwind storage tank on gas diffusion based on three (1.05H, 0.90H, and 0.77H, H was the tank height, 22m) leakage field experiments on the leeward side of storage tank, which have been not conducted before. The experiments revealed an unexpected phenomenon: the maximum ground concentration first decreased and then increased with increasing leakage height. The simulations illustrated that the differences in micrometeorological conditions caused the maximum ground concentration of gas emitted from the roof to be higher than that emitted from the tank wall near the storage tank height. The downwind storage tank 1) had little influence on the entire diffusion direction but altered the local diffusion pattern; 2) reduced the maximum ground concentration (∼18.7%) and the distance from the emission source (approximately a storage tank diameter); and 3) had strong influences on the concentration, velocity, turbulence, and pressure on the leeward side. The concentration negatively correlated with the velocity, pressure, and turbulence in the middle of the two storage tanks on wind centerline. Our results can improve understanding of gas dispersion in tank areas and provide references for mitigating loss and protecting lives during emergency response processes. 相似文献
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为探究隧道横通道通风对隧道火灾烟气蔓延的影响规律,使用火灾动力学模拟软件FDS,对不同火源位置的横通道临界风速、主隧道温度分布以及烟气层高度进行研究。研究结果表明:在一定火源功率范围内,隧道横通道临界风速与火源功率的1/3次方成正比且火源距横通道越远,临界风速越小;当火源位于交叉口,横通道使用临界风速通风时,隧道内烟气温度明显降低,烟气迅速沉降到2 m以下;当火源距离交叉口10,20 m,横通道通风会加快火源下游烟气沉降,烟气沉降速度随横通道通风速率的增大而增大;当火源位于交叉口时,烟气沉降由横通道通风对烟气的降温作用和涡旋作用共同主导,当火源位于距离交叉口10,20 m时,烟气沉降主要由涡旋作用主导。 相似文献
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根据多孔介质渗流理论,利用Fluent软件,分别对采空区瓦斯在整个采空区均匀涌出、上邻近层及底板遗煤涌出2种情况下采空区瓦斯分布规律进行了数值模拟.结果表明:采空区瓦斯为上邻近层及底板遗煤处涌出时,沿走向方向,靠近上邻近层及底板处高体积分数瓦斯距离工作面较近;沿竖直方向,瓦斯体积分数分布呈钩状,靠近瓦斯涌出源处瓦斯体积分数最高;整个采空区均匀涌出时采空区瓦斯体积分数分布与上邻近层及底板遗煤涌出时有很大差别.因此,为了得到更符合实际情况的瓦斯分布规律,数值模拟时应按照现场实际的瓦斯涌出源位置建立模型. 相似文献
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The industrial layout traditionally has been addressed accounting for the facilities distribution and installation since the first day of operation of the plant; this is, without considering future expansions that involve additional facilities in the future operation years. This way, this paper proposes a mathematical programming formulation for the optimal facility sitting and reallocation in an industry accounting for future expansions and involving simultaneously economic and safety objectives. The proposed formulation is based on a multi-annual framework and this corresponds to a multi-objective mixed integer linear programming problem. The proposed optimization approach was applied to a case study for the facility sitting (office buildings and control rooms) in an ethylene oxide plant. The economic objective function involves the minimization of the total annual cost accounting for the value of the money through the time and the safety objective function involves the minimization for the accumulated risk over the operation time. Results show the applicability of the proposed approach. 相似文献
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Trace element concentrations were studied in soils of the King George and Elephant islands in the maritime part of West Antarctica. The lowest concentrations of Cu, Pb, Cd, Zn, Ni and Mn were typical for the pristine soil of Elephant Island. The highest concentrations of these elements were found in the Fildes Peninsula and revealed the influence of human activities in the area of the Bellingshausen station and adjacent waste disposal sites. Ornithogenic soils of the Fildes Peninsula have shown low concentrations of Cd and As. Using geoaccumulation indexes, all the pristine soils of King George and Elephant islands and ornithogenic soils of the Fildes Peninsula were classified as unpolluted; the human-affected soils were mainly identified as moderately polluted. Obtained data can be used as background concentration levels for further researches. 相似文献