Techno-economic analysis on CO2 mitigation by integrated carbon capture and methanation

Carbon capture and utilization (CCU) by methanation combines CO2 capture and Power-to-Gas (PtG) routes, and could simultaneously realize excess clean energy storage and industrial flue gas carbon mitigation. However, a problem of large energy consumption is associated with the long-chain CCU-methanation process. In contrast, integrated carbon capture and utilization (ICCU) could largely reduce energy consumption by integrating CO2 capture and methanation in just one reaction device. Although progressive work has been done on the development of ICCU-methanation, it still lacks of quantitative evaluation on the energy consumption and production cost. Herein, techno-economic analysis is conducted on calcium looping-based ICCU-methanation and the reference CCU-methanation. Results show that ICCU-methanation only requires 1/3 coal consumed by CCUmethanation to complete carbon capture of a 1000 MWe coal-fired power plant. When waste heat recovery is considered, the plant equipped with ICCU releases 83.6 kg CO2 per 1 MWe h-1 of electricity comparing to 148.93 kg of CCU. Meanwhile, CH4 cost by ICCU scheme is 837.1 euro t-1, much lower than the 962.86 euro t-1 of CCU. After taking the recovery of waste heat and carbon tax into account, the cost of CH4 produced by ICCU becomes to be 443.26 euro t-1, approaching the market price of natural gas (429 euro t-1), showing a promising application perspective.