油页岩原位开采的大气环境风险评估

 在近临界水油页岩原位开采过程中,会产生一些有毒有害气体(H₂S、苯、甲苯等),这些气体可能通过法兰接口、输送管道破损处、多级地质裂隙及废弃井外侧地质裂隙泄漏,带来一定的风险隐患。本文以吉林某地区油页岩原位开采为例,对其进行了空气环境的风险计算与评价。结合该区油页岩原位开采的生产工艺,确定H₂S、苯、甲苯为本次环境风险评价的风险评价因子,通过源项分析对它们的泄漏量进行了计算,结果为H₂S 92.1kg/s,苯3.168kg/s,甲苯0.109kg/s,风险类型为泄露。同时,本文对最大可信事故进行了后果计算,结果表明输送管道或法兰接口发生破裂泄漏后厂区内H₂S的车间最高容许浓度超标。在风速为2m/s时,H₂S、苯及甲苯出现浓度值超过职业接触限值现象;H₂S、苯在厂区及附近100m范围内存在浓度超过立即危害生命和健康浓度限值现象,甲苯未超标;H₂S浓度发生超出急性毒害限值现象,苯及甲苯未超标。短时间发生泄漏事故影响区域主要为厂区内部。鉴于风险计算和评价,本项目的风险值水平低于同行业标准,环境风险可接受。为了最大程度地降低风险事故发生的概率及对周边环境的影响,本文提出了一些防范及管理建议。

Risk Assessment of the Atmospheric Environment During In-situ Oil Shale Exploitation

Some poisonous gases, like H₂S, benzene and toluene, will be produced in the process of in situ shale-oil extraction. These gases may leak out through the flange interface, the pipeline breakage, the geological crack and the outer side of an abandoned well. In this study, the risk of the air environment is assessed and evaluated in the in-situ shale-oil extraction in a country of Jilin Province, China. The most credible accident consequences are calculated at the same time. It is shown that, after leakage from the flange interface or the pipeline or after rupture, H₂S tends exceed the maximum allowable concentration in the workshop in the plant area. The concentration values of H₂S, benzene and toluene exceed the occupation contact limiting values when the wind speed is 2m/s. The concentrations of H₂S and benzene exceed the value of the immediate danger to life and the health concentration limitation. Toluene value is within the standard. H₂S concentrations exceed the limit value of acute poisoning phenomenon, while those of benzene and toluene are within the standard. The plant area is mainly affected during the short time of the leakage accident occurring. According to the risk calculation and evaluation in this study, the project risk level is lower than the same industry standard. The environmental risk is acceptable. In order to minimize the probability of the accident risk and the impact on the surrounding environment, we put forward some prevention and management suggestions.