基于泄漏扩散后果评价的CO_2管道截断阀间距确定

The determination of the spacing between block valves of CO_2 pipelines based on the consequence assessment of leakage and diffusion

为了保障CO_2的输送安全,从CO_2泄漏扩散的后果出发,考虑CO_2泄漏扩散时的相态变化及重力的影响,利用PHAST软件建立CO_2管道的泄漏扩散模型,以最不利工况作为初始条件,计算不同阀间距下的SLOD(致死率等于50%)影响范围,从而确定CO_2管道不同等级地区下的阀间距。结果表明:一级地区从安全考虑并不需要建设阀室,但是为了方便管道维修,可以在便于维修的部位建立阀室;二级地区可以根据相应的户数选择合适的阀间距,但最大不超过60 km;三、四级地区不推荐超临界CO_2管道输送。研究成果可为中国CO_2管道输送相关规范的制定,以及对CO_2管道进行安全评价和事故后果分析提供一定的理论支持。

To ensure the CO2 transmission safety, a leakage and diffusion model for CO2 pipelines was established using the software PHAST. In this model, the consequence of CO2 leakage and diffusion is taken as the basis, and the phase change and gravity effect during CO2 leakage and diffusion are taken into account. Then, the SLOD（death rate 50%） influence ranges at different valve spacing were calculated with the most unfavorable conditions as the initial condition, so as to determine the valve spacing of CO2 pipeline in the areas of different levels. It is shown that for the sake of safety, a valve chamber shall not be constructed in level-one areas, but to carry out pipeline maintenance conveniently, a valve chamber can be installed in the location which is conducive to pipeline maintenance. The valve spacing in level-two areas can be selected according to the number of customers, but it shall not exceed 60 km. It is not recommended to conduct supercritical CO2 transmission in level-three and level-four areas. To sum up, the study on the valve spacing of CO2 pipelines based on the consequence assessment of leakage and diffusion provides some theoretical support for the formulation of specifications related with CO2 pipeline transportation and the safety evaluation and accident consequence analysis on CO2 pipelines in China.