东海某平台可燃气体冷放空扩散安全评估研究

Research on Safety Assessment of the Diffusion of Combustible Gas Cold Venting on a Platform in East China Sea

陈磊

CHEN Lei

中国石油化工股份有限公司上海海洋油气分公司石油工程技术研究院，上海　200120

Institute of Offshore Petroleum Engineering, SINOPEC Shanghai Offshore Oil & Gas Company, Shanghai 200120, China

以东海某平台为例，采用数值模拟的方法研究不同工况条件下可燃气体冷放空的扩散规律，选用k-epsilon模型和Species Transport模型分别描述气相湍流运动和可燃气体扩散过程。结果表明：冷放空排放气体扩散受环境风向影响较小；冷放空排放气体扩散受风速条件和泄放放空速率的影响明显，随着环境风速的变大，火炬头上方形成的可燃气体团越小，可燃气体团中心距离火炬头越来越近；随着放空速率的变大，火炬头上方形成的可燃气体团越大，可燃气体团中心距离火炬头越来越远；意外熄灭工况、火灾工况和阻塞工况条件下，对应的最大扩散距离分别为15.69 m、20.62 m和28.48 m；直升机远离火炬头安全飞行的距离分别为16 m、21 m和29 m。建议平台加强可燃气体探测系统维护，确保能够及时探测到冷放空气体。

Taking a platform in East China Sea as an example, the method of numerical simulation was used to study the diffusion law of combustible gas under different conditions. The k-epsilon model was used to describe the turbulent motion of the gas phase, and the Species Transport model was used to describe the combustible gas diffusion process. The results showed that the diffusion of cold venting exhaust gas was less affected by the environmental wind direction. The diffusion of cold venting exhaust gas was significantly affected by wind speed conditions and venting rate. As the ambient wind speed increased, the combustible gas cluster formed near the torch head became smaller and the center of the combustible gas cluster became closer to the torch head. With the increase of the discharge rate, the larger the combustible gas cluster formed near the torch head, and the center of the combustible gas cluster was farther away from the torch head. Under the conditions of accidental extinguishing, fire and blocking, the corresponding maximum diffusion distances were 15.69 m, 20.62 m and 28.48 m, respectively. The safe flight distances of helicopters away from the torch head were 16 m, 21 m and 29 m respectively. It was suggested that the platform should strengthen the maintenance of combustible gas detection system to ensure timely detection of cold venting gas.

https://doi.org/10.3969/j.issn.1008-2336.2023.01.093