页岩气开发油基钻屑-单组分生物质共热解特性

Co-Pyrolysis Characteristics of Oil-based Drill Cuttings and One-Component Biomass in Shale Gas Exploitation

油基钻屑与生物质热解油分别存在产率低、有害组分含量高的问题,为探究二者共热解是否可以产生协同作用,采用固定床反应器研究了热解温度、终温时间(热解温度保持时间)、升温速率、N2流量、生物质与油基钻屑混合比例(质量比)等因素对油基钻屑与单组分生物质共热解的影响.结果表明:①油基钻屑与单组分生物质热解效果随热解温度和终温时间的增加而增强、随升温速率的加快而减弱,N2流量对热解过程影响不大;最佳热解工艺参数为热解温度350℃、终温时间60 min、升温速率10℃/min、N2流量0. 15 L/min.②共热解可产生协同作用,当生物质与油基钻屑混合比例分别为3∶7、7∶3时,热解灰渣含油量较理论值下降较为明显,降幅分别为21. 71%、17. 64%.③共热解可减少生物质热解过程中有害物质的生成,提高油基钻屑的液相产率,生物质单独热解时液相产物中有害组分占比高达74. 92%;加入适量油基钻屑共热解时有害组分占比明显降低,当油基钻屑与生物质混合比例为7∶3、8∶2时,有害组分占比可分别降至22. 74%、17. 57%.研究显示,共热解产生的协同作用可减少有害物质的生成,提高热解油产率,在油基钻屑无害化、资源化利用与生物质开发中具有良好的应用前景.

The oil production rate of oil-based drill cuttings pyrolysis is low and the amount of harmful components in the oil produced by biomass pyrolysis is high. In order to explore whether the co-pyrolysis of the two can produce synergistic effects,a fixed-bed reactor was employed to investigate the effects of the main factors,including pyrolysis temperature,final temperature retention time,heating rate,nitrogen flow and mixing ratio,on the co-pyrolysis of oil-based drill cuttings and biomass. The results showed that the pyrolysis effect increased with the increase of the final temperature and the final temperature retention time,and decreased with the acceleration of the heating rate. The nitrogen flow had a minor effect on the pyrolysis process. The optimal pyrolysis process parameters were 350 ℃ of pyrolysis temperature,60 min of final temperature retention time,10 ℃/min of heating rate and 0. 15 L/min of nitrogen flow. The co-pyrolysis resulted in favorable synergies. When the proportion of biomass or oil-based drill cuttings was 30%,the oil content of the pyrolysis residue was lower than the theoretical value by 21. 71% and 17. 64% respectively. Co-pyrolysis reduced the generation of harmful substances in the pyrolysis process of biomass and increased the liquid yield of oil-based drill cuttings. The harmful components in the biomass pyrolysis liquid products went up to 74. 92%,which were significantly reduced by adding an appropriate amount of oil-based drill cuttings. When the ratio of oil-based drill cuttings to biomass is 7 ∶ 3 and 8 ∶ 2,the harmful components were reduced to 22. 74% and17. 57%,respectively. The research determined that co-pyrolysis could reduce the formation of harmful substances and increase the yield of pyrolysis oil. It has promising applications in the treatment and resource utilization of oil-based drill cuttings and the development of biomass.