孔德辉,刘东,郭书海,师楠,温福山,吴波,李刚,殷长龙,杨修洁,乔堉锴.石油污染土壤热解修复反应规律与机制研究[J].环境科学学报,2021,41(8):3339-3348
石油污染土壤热解修复反应规律与机制研究
- The mechanism of pyrolysis and remediation of petroleum contaminated soil
- 基金项目：国家重点研发计划项目（No.2018YFC1801901）
- 孔德辉
- 中国石油大学(华东)化学工程学院重质油国家重点实验室, 青岛 266580
- 刘东
- 中国石油大学(华东)化学工程学院重质油国家重点实验室, 青岛 266580
- 郭书海
- 中国科学院沈阳应用生态研究所, 沈阳 110016
- 师楠
- 中国石油大学(华东)化学工程学院重质油国家重点实验室, 青岛 266580
- 温福山
- 中国石油大学(华东)化学工程学院重质油国家重点实验室, 青岛 266580
- 吴波
- 中国科学院沈阳应用生态研究所, 沈阳 110016
- 李刚
- 中国科学院沈阳应用生态研究所, 沈阳 110016
- 殷长龙
- 中国石油大学(华东)化学工程学院重质油国家重点实验室, 青岛 266580
- 杨修洁
- 中国石油大学(华东)化学工程学院重质油国家重点实验室, 青岛 266580
- 乔堉锴
- 中国石油大学(华东)化学工程学院重质油国家重点实验室, 青岛 266580
- 摘要：在石油的开采、运输等过程中，由于原油泄漏而产生的石油污染土壤会严重威胁生态环境和人类健康.相比细菌降解修复和化学氧化修复，中低温热解修复是一种高效、经济的修复方法.然而，国内对石油污染土壤的热解修复规律和影响因素研究却较少.本文先以模型污染土壤为研究对象，考察了初始含油率（5%、10%）、热解温度（375、400、425、450 ℃）、热解时间（30、60 min）对污染土壤中石油烃脱除率的影响，采用FTIR、元素分析、原油四组分分析、荧光显微镜观测等方法确定了热解过程中石油的饱和分、芳香分、胶质及沥青质的转化方式，提出了石油污染土壤在形成和热解过程中石油的四组分吸附、脱除途径模型，并通过XPS、TEM等表征手段确定了最佳修复条件.结果表明，在425 ℃下热解30 min后，污染土壤中石油烃去除率在99.40%以上，残存TPH含量低于GB I类用地风险筛选值，且修复后土壤中的残炭非常稳定、无害，不会对环境造成二次污染.此外，还选取了新疆油田、长庆油田的场地石油污染土壤在最佳修复条件下进行处理，发现石油烃脱除率均在99.60%以上，土壤总有机碳含量的结果也表明处理后的土壤肥力恢复到了污染前的水平.本研究结果将为我国高浓度石油污染土壤的热解修复技术提供科学依据.
- Abstract：Petroleum-contaminated soil produced by crude oil leakage in petroleum exploration and transportation seriously threatens the ecological environment and human health. Compared with bacterial degradation and chemical oxidation, medium-low temperature pyrolysis is a much more efficient and economical approach of soil remediation. However, limited efforts have been made domestically on pyrolysis remediation of petroleum-contaminated soil. Herein, a series of model contaminated soils were primarily prepared and pyrolyzed under different conditions to investigate the effects of initial oil content (5%, 10%), pyrolysis temperature (375, 400, 425, 450 ℃), and pyrolysis time (30, 60 min) on pollution removal. The conversions of saturated components, aromatic components, gums and asphaltenes during the pyrolysis process were comprehensively explored by analyzing the results of FTIR, element analysis, four-component analysis of crude oil, and fluorescence microscope, and a model of four-component adsorption and removal pathway of petroleum during the PCS formation and pyrolysis was proposed. The optimum repair condition was determined by XPS, TEM and other characterization methods. The results above indicated that after pyrolysis at 425 ℃ for 30 minutes, more than 99.40% of petroleum hydrocarbons in the contaminated soil could be removed, with the residual TPH content lower than the GB I category risk screening value. The residual carbon in the soil is stable and harmless, without causing secondary pollution to the environment. To further evaluate our approach, petroleum-contaminated soils from Xinjiang Oilfield and Changqing Oilfield were selected for treatment under the optimum remediation conditions, and the removal rate of petroleum hydrocarbons above 99.60% was obtained. The results of the soil total organic carbon content convinced that the fertility of treated soil could recover to the level comparable to unpolluted soil. This work provides a scientific basis for the pyrolysis remediation technology of high-concentration petroleum-contaminated soil in our country.
