Full Chain Analysis,integration And Optimization Of CO₂ Capture,utilization And Storage Technology

The large amount of greenhouse gas emissions will have a serious impact on climate,agriculture,ecology and other aspects.The issue of carbon dioxide-based greenhouse gas emissions has become the focus of various countries.According to a report released by the International Energy Agency?IEA?,global energy-related carbon emissions continued to grow in 2019,reaching 33.1 billion tons.The Intergovernmental Panel on Climate Change?IPCC?report pointed out that to achieve the goal of controlling global warming temperature at 1.5?,countries must take urgent action to avoid the serious consequences of massive greenhouse gas emissions.Currently recognized effective measures to reduce greenhouse gas emissions include improving the efficiency of existing energy use,increasing the proportion of renewable energy,and implementing carbon dioxide capture,utilization and storage technology?CCUS?.As the main CO₂ emitter,China is vigorously developing new energy sources to reduce CO₂ emissions in the energy industry currently,but China's energy structure is“more coal,less oil and gas”,coal will still play an important role in the foreseeable future.Because the deployment of CCUS technology does not require large-scale adjustment of the existing energy structure,also,it has good compatibility with China's existing energy structure,and at the same time can achieve large-scale CO₂ emissions reduction,it has broad development in China prospect.This article will take CCUS full chain as the analysis object,and the research content mainly includes the following aspects:Use Aspen plus chemical simulation software to build and verify the model of350MW supercritical coal-fired power plant with MEA post-combustion capture system.Taking this model as an example,from the perspective of the integration of the energy system and the capture system,it proposes a deep understanding of the carbon capture energy consumption issue,and divides the energy consumption into direct energy consumption related to the capture process and the indirect energy consumption related to system integration,upon the classification,yields the theoretical maximum thermal efficiency of the energy system after integrated with carbon capture.Based on this theoretical analysis,the influence of important process parameters on the thermodynamic properties such as direct energy consumption,indirect energy consumption,and theoretical thermal efficiency of the capture system is obtained,and then the carbon capture integrated system is optimized.The optimized desorption pressure is 1.9bar,the lean absorbent load is 0.22mol/mol,and the lean absorbent mass concentration is 30%.At this time,the direct energy consumption of the integrated system is 40.8kJ/mol,and the indirect energy consumption is 13.4kJ/mol.When indirect energy consumption equals 0,the efficiency of the system will be 33.2%,and the actual thermal efficiency is 30.5%.In the IECM simulation software,the low-concentration carbon source of the supercritical power plant?SCPC?and the high-concentration carbon source of the IGCC power plant carbon source,with saline aquifer sequestration?SAS?and enhanced oil recovery?EOR?sink are chosen to forming four typical CCUS full chain cases.The thermal performance,emission reduction effect and economic performance of the full chain are obtained,and sensitivity analysis of fuel prices,power plant capacity factors and carbon capture are conducted to obtain the law of full chain performance.For the SCPC full-chain case,the direct energy consumption of the system is 21.7 kJ/mol,the indirect energy consumption is 39.1 kJ/mol,the thermal efficiency is 25.5%,and the thermal efficiency is 32.4%when the indirect energy consumption is 0.The economic performance of the SCPC full-chain case will deteriorate with the increase in coal prices,the reduction in the annual average load rate of the power plant and the increase in the carbon capture ratio.For the IGCC full-chain case,the direct energy consumption is5.5 kJ/mol,the indirect energy consumption is 33.7 kJ/mol,the thermal efficiency is34.9%,and the thermal efficiency of the power plant is 40.5%when the indirect energy consumption is 0.The economic performance of the IGCC full-chain case will deteriorate due to the increase in fuel prices and the decrease in the average annual load rate of the power plant.The cost of full-chain electricity will increases with the increase of the carbon capture ratio,but the change trend of the cost of full-chain CO₂ avoided with the carbon capture ratio is opposite.In order to study the impact of source-sink matching on CCUS full-chain performance and obtain the integration principle of CCUS full chain,a comprehensive comparative evaluation of the four cases of SCPC-SAS,SCPC-EOR,IGCC-SAS,and IGCC-EOR was conducted.The analysis results show that when the IGCC power plant carbon source is used,the full-chain emission reduction effect is the same as that of the SCPC carbon source,but it has better thermal performance and economic performance;When EOR is used as a carbon sink,the full chain has the same thermal performance and emission reduction effect compared with SAS carbon sink,but has better economic benefits.In addition,when performing CCUS full chain integration planning,if the fuel supply and power plant load are stable,and the target amount of carbon capture may occur,it is more suitable to choosing EOR carbon sink,and SAS carbon sink is more advantageous under the opposite conditions.Based on AHP method,a comprehensive evaluation model of CCUS full chain was constructed.The CCUS source-sink combination case with supercritical coal-fired power plants and IGCC power plant as carbon sources,geological storage of saline aquifers and enhanced oil displacement as carbon sinks was analyzed under the national,capital,and enterprise goals,and the optimal plan results under different goals were obtained for early deployment of CCUS,showing that under the national and enterprise goals,the SAS-EOR plan is the most suitable plan for the early CCUS demonstration,under the capital target,the IGCC-EOR is the most suitable CCUS plan for development.