School of Chemical and Environmental Engineering,China University of Mining & Technology-Beijing
Binzhou Institute of Technology

碳捕集与转化利用是应对气候变暖、实现“双碳”目标的重要技术手段之一。化学吸收法是目前发展成熟的碳捕集技术之一,但面临CO2富液再生能耗高的问题。为降低碳捕集成本,提出了一种基于嗜氢型甲烷化的CO2富液生物再生方法,即以Na2CO3和微生物营养液配制pH为10的溶液作为CO2吸收剂,同时利用嗜氢型甲烷化过程将吸收富液中的CO2转化为CH4,实现CO2富液再生和吸收剂循环利用。为提高CO2生物转化速率,构建了一种潮汐式嗜氢型甲烷化反应器,在完成该反应器启动阶段运行性能研究的基础上,考察了该反应器用于CO2富液生物再生的可行性。结果表明:潮汐式嗜氢型甲烷化反应器在第33天时的气体停留时间(GasResidenceTime,GRT)达到23min,反应器出口CH4体积分数为95%左右,CO2转化速率是常规滴流床和固定床的10倍左右;启动阶段的pH、碱度基本保持稳定,未出现明显的有机酸积累现象,有机酸总浓度平均值为0.2~2.3mmol/L。在随后5个周期的CO2富液生物再生试验中,再生后吸收剂的CO2吸收量平均值为55mmol/L,标准差为1.1mmol/L,再生后吸收剂的pH稳定在9.53±0.05,说明基于嗜氢型甲烷化的CO2富液生物再生可基本实现吸收剂的循环利用;CO2富液生物再生试验结束后,反应器内耐碱性细菌属Proteiniborus、Acinetobacter以及古菌属Methanobacterium的相对丰度增加,说明微生物通过群落结构调整逐步适应在弱碱性条件下开展CO2甲烷化等代谢活动。

To counteract global warming and reach the “double carbon” target,carbon capture,conversion,and utilization (CCCU)is a crucial technical strategy. One of the most recognizable carbon capture techniques,chemical absorption requires a lot of energy toregenerate CO2-loaded solutions. Bio-regeneration of CO2-loaded solutions using hydrogenotrophic methanation was proposed here forreducing carbon capture costs. In this method,a solution with a pH of 10 was prepared with Na2CO3 and microbial nutrient solutions asCO2 absorbents,and hydrogenotrophic methanation was used to convert CO2 to CH4 so that the solution could be regenerated and theabsorbent reused. Initially, a tidal hydrogenotrophic methanation reactor was developed in order to increase the rate of CO2bioconversion. Its viability for bio-regeneration of CO2-loaded solutions was determined after examining its startup performance. Theresults showed that on day 33,the gas residence time (GRT) of the tidal hydrogenotrophic methanation reactor had reached 23 minutes 2and the CH4 content at the reactor outlet was about 95%, indicating a CO2 conversion rate about 10 times higher than that of theconventional trickling bed and fixed bed. During the start-up phase, pH and alkalinity were essentially stable, there was no obviousaccumulation of organic acids,and the average total organic acid concentration ranged from 0.2 to 2.3 mmol/L. In the subsequent 5 cyclesof CO2-loaded solution bio-regeneration experiments, the regenerated absorbent’s mean CO2 uptake was 55 mmol/L with a standarddeviation of 1.1 mmol/L. The pH of the regenerated absorbent remained stable at 9.53±0.05,indicating that a CO2-loaded solution basedon hydrogenotrophic methanation could effectively recycle absorbent. In the reactor,the relative abundance of the alkali-tolerant bacterialgenera Proteiniborus and Acinetobacter and the archaeon Methanobacterium increased after the CO2-loaded solution bio-regenerationexperiment. Results indicate that microorganisms have progressively adapted to weakly alkaline environments by reorganizing theircommunities to conduct metabolic processes such as CO2 methanation.

国家自然科学基金青年科学基金资助项目(51908547);教育部产学合作协同育人资助项目(220506429102839)

苗佳慧,王建城,代雅男,等.潮汐式嗜氢型甲烷化性能及其用于CO2富液再生可行性[J].洁净煤技术,2024,30(11):104−111.

MIAO Jiahui,WANG Jiancheng,DAI Yanan,et al. Performance of tidal hydrogenotrophic methanation and its feasibility for regenerating CO2-loaded solutions[J].Clean Coal Technology,2024,30(11):104−111.