Dispersion characteristics and hazard area prediction of mixed natural gas based on wind tunnel experiments and risk theory

Autor: Baoquan Xin, Wenyi Dang, Jianliang Yu, Yongzhong Bai, Xingqing Yan
Rok vydání: 2021
Předmět:
Zdroj: Process Safety and Environmental Protection. 152:278-290
ISSN: 0957-5820
Popis: As a complex mixture, high-hydrogen-sulfide natural gas has a high risk of poisoning and explosions after leakage. This study combined wind tunnel experiments, computational fluid dynamics (CFD) technology, and risk theory to explore the dispersion characteristics and hazardous area of released mixed natural gas (M-NG) in complex terrain. Based on risk theory, various external safety protection distances under four kinds of risk criteria were predicted. The results indicated that the dispersion process of M-NG in mountainous terrain can be divided into two components: downhill dispersion and cut-slope dispersion. At the same wind speed, the maximum concentrations for different wind directions can differ by a factor of 10. Compared with the results of the wind tunnel tests, the maximum overestimation was 62.9% when simulating the near-field dispersion of M-NG by CFD, while the underestimation was 28.1% for the far-field dispersion. The critical distance was about 1042 m, the dispersion time was 960 s, and the gas concentration was 42 ppm. The wind speed, wind direction, topography, and their interactions have an important impact on the dispersion process and hazard area of M-NG. The study also indicated that in the quantitative risk assessment, more attention should be paid to the toxic hazard of hydrogen sulfide in M-NG rather than the explosion hazard caused by methane. The risk method fully considers the frequency of accidents and the types of protection targets. It can thus be used as a reference for site selection, land use planning, and emergency protection.
Databáze: OpenAIRE