| The post-combustion CO2 capture system can significantly reduce CO2 emissions from power plants,thereby reducing the value of global warming potential.However,applying the capture system will bring new hazard to the environment including acidification,eutrophication,ozone depletion and other environmental impacts due to equipment construction,energy consumption and chemical demand.In this paper,the life cycle environmental assessment of the post-combustion CO2 capture system is carried out to explore the impact of different absorbents and the operating parameters and processes.In addition,the carbon capture system was coupled to a power plant to evaluate the environmental impact of the CCS system based on the coal-electric chain in different carbon dioxide disposal paths.Based on the construction and operation data of an actual 100,000 tons/year post-combustion CO2 capture demonstration system,a life cycle environmental assessment was accomplished innovatively using a new kind of compound amine absorbent,compared with the traditional absorbent monoethanolamine.According to the results,although the direct emissions turned to 11%,the whole life cycle GHG emission reduction rate of the demonstration system is only 45%-51%.The power consumption and heat consumption during the capture process along with power consumption during the compression process are the most significant part of the environmental impact,accounting for more than 76%.The absorbents assumption and waste treatment processes account for less than 5%.Comparing the two absorbents,the compound amine's performance is 10-20%better than that of monoethanolamine,especially in the item of human toxicity,reaching 33%.The total energy consumption of the whole life cycle is also reduced by 15.8%compared with the latter one.Based on Aspen Plus and self-built amine absorbent degradation and waste treatment models,this paper evaluates the life cycle impact assessment,energy consumption and water consumption of monoethanolamine,compound amine and piperazine at the capacity 100,000 tons/year.The overall environmental impacts of the compound amine absorbent are optimal;the piperazine is better in terms of energy consumption and greenhouse effect.the direct energy consumption accounts for about 50%of the total energy consumption.The water consumption of the compound amine absorbent is comparable to piperazine,and the direct water consumption accounts for 44%of the total water consumption.The operating parameters and process optimization of the system shows that the lean liquid load,the desorber pressure,the flue gas temperature and the capture rate have a significant impact on the system's energy consumption,water consumption and environmental assessment.The intercooled absorber and rich solvent splitting processes respectively reduced the greenhouse effect of the system by 2.7%and 2.5%compared to the baseline.Based on China's inventory data,the environmental impacts of coal-electric chain based on an ultra-supercritical power plants were investigated with and without the installation of CCS system.The selected absorbent was the compound amine absorbent optimized by exact operating parameters and process.The results showed that although the power plant efficiency decreased by 10.1%,the global warming potential decreased by 59%.The overall environmental impacts can be found to be more friendly after the installation of the CCS system,but the energy demand increased by 33.4%,as well as the water consumption increased by 92.7%.In addition,the impact assessment results also show that coal mining play a leading role in environmental impact.The paper also explores the impact of CO2 utilization substitutes CO2 storage.The enhanced oil recovery scenario reduces most environmental assessment items by 5%-10%,and mineralization reduces the global warming potential by 30.8%while bringing small increase in others environmental assessment items such as acidification and eutrophication potential. |
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