地质封存二氧化碳微生物转化研究进展

Research advances of microbial transformation of CO2 in geological sequestration

摘要:

碳捕获、利用与封存(carbon capture, utilization and storage, CCUS)是实现我国“双碳”目标的重要技术手段，微生物活动是CO₂地质封存过程中不可忽视的一部分。部分微生物可将封存CO₂转化为甲烷或有机酸以实现资源利用，也可转化为碳酸盐实现长久固定，这些微生物活动有助于实现CO₂的稳定封存与负碳排放。本文分析了深地封存CO₂可能涉及的微生物甲烷化、液化、矿化机理，综述了各转化途径的研究进展。CO₂微生物甲烷化和液化技术能够将封存CO₂转化为甲烷或高值有机物，实现资源再利用，二者既能单独使用，也可以耦联应用以扩大CO₂生物转化的应用范围。CO₂微生物矿化利用微生物诱导碳酸钙沉淀将CO₂转化为方解石，是一种极具潜力的固定CO₂和限制CO₂逃逸技术。目前CO₂微生物转化仍处于起步探索阶段，亟须从转化原理及影响因素、转化效率、经济性和环保性、工艺条件等方面开展深入研究，建立健全CO₂地下原位生物转化理论技术体系，并与CCUS结合建立“捕、输、驱、封、转、采”一体化技术体系，助力CCUS的高值应用和我国“双碳”目标的实现。

Abstract:

Carbon capture, utilization and storage is the vital technology for China to achieve the goals of carbon peaking and carbon neutrality. Microbial activities in situ are an indispensable part in the process of geological CO₂ sequestration. Some microorganisms can convert CO₂ into methane and organics as the resource for utilization or into carbonate to achieve long-term sequestration. These activities contribute to the stable storage of CO₂ and even negative carbon emission. This paper focuses on the processes of bio-methanation, bio-liquefaction, and bio-precipitation that may be involved in CO₂ sequestration in deep stratum and discusses the research progress in the bio-transformation pathways. Bio-methanation and bio-liquefaction can convert CO₂ into methane or high-value organic compounds to realize resource reuse. The two technologies can be used alone or coupled to expand the application range of CO₂ biotransformation. Bio-mineralization can convert CO₂ into calcite by microorganism-induced carbonate precipitation, being a technology of great potential in fixing CO₂ and limiting CO₂ escape. At present, this field is still in the infancy stage, and there is an urgent need to establish and improve the theoretical and technical systems of CO₂ in-situ biotransformation from transformation principle, influencing factors, conversion efficiency, economy, environmental protection, and technological conditions. Moreover, it can be combined with CCUS to establish a technical system integrating capture, transport, displace, storage, transfer, and exploit, so as to promote the value-added application of CCUS and the achievement of carbon peaking and carbon neutrality.