Research On Efficient Biomass Utilization System Based On Coupling Of Multiple Thermal-chemical Processes

In order to improve the efficiency of biomass utilization process,this paper proposes a system integrated with coal-fired power plant and supercritical carbon dioxide(S-CO2)cycle and a system integrated with fuel cell,carbon capture and medical waste plasma gasification from the perspective of system coupling by combining two different biomass power processes with multiple systems separately.The proposed system itself and the components were modeled and simulated using Aspen Plus and Ebsilon Professional.The system was evaluated in multiple dimensions by proposing three analysis indexes:energy analysis,exergy analysis and economic analysis.For the first integrated system proposed,the results show that the biomass gasification process is combined with the S-CO2 cycle,gas turbine and coal-fired power plant processes,and the energy in biomass is gradually utilized by S-CO2,gas turbine and power plant feedwater.Taking an 8t/h gasifier and 350MW coal-fired power plant as an example,the energy and exergy efficiency of biomass power generation can reach 41.39%and 40.58%separately while not affecting the reference plant.The project is expected to cost 4,841.03k$ with a net present value of 31,358.34k$ and discounted payback period of 1.07 years.For second integrated system proposed,the analysis results show that the biomass combustion power generation process combined with the medical waste plasma gasification utilization,solid oxide fuel cell and carbon dioxide capture and storage(CCS)process provides different grades of steam and feed water through the biomass power plant,and the energy from the medical waste gasification process is effectively recovered while providing suitable heat for the CCS process.Taking a 34MW biomass power plant as an example,the energy efficiency of medical waste generation can reach 35.10%and the exergy efficiency 33.58%,when the CCS unit is put into operation.The system required an investment of 69.27 M$,with a projected net present value of 44.72 M$ and discounted payback period of 5.95 years.The integrated system will fix 59.84 million tons of CO2 per year.The two systems studied in this paper,with biomass as the new element and the coupling basis,respectively,coupled with other elements based on energy level matching considerations,are expected to provide some insights for the subsequent improvement of biomass utilization efficiency by means of system integration.