| Since the reform and opening up policy,our country’s economy has continued to develop rapidly and energy consumption has increased year by year.Now,China is the largest energy producer,energy consumer,and carbon emitter of the world.As the energy structure of our country is dominated by coal for a long time,and oil and gas are highly dependent on foreign sources,the need for a clean and low-carbon transition of energy is urgent.At present,the government is paying more and more attention to energy conservation and utilization.President proposed the goal of "carbon peak and carbon neutrality".Therefore,the power industry should diversify the development of integrated renewable energy systems to increase the share and utilization efficiency of renewable energy and solid waste in power generation,fulfill the promise of social responsibility and energy conservation and environmental protection.Based on the above background,this subject proposes two solar-assisted biomass-fired cogeneration system integration schemes.The solar thermal energy collected by the concentrating heat collection technology is introduced into the steam-water cycle of the biomass plant.The design condition and sensitivity variation models are established by simulation software,supplemented by thermodynamic and economic analysis calculation,which conduct research on the synergy mechanism and economic feasibility of the integrated scheme.First of all,a solar-assisted biomass-fired cogeneration system based on an absorption heat pump is proposed:solar thermal energy is used to drive the absorption heat pump to heat the supply-water during the heating period,reducing extraction steam for heating;and during the non-heating period,it is used to heat the feedwater to save high-pressure extraction steam,which is both helpful to increase the power generation.After the system integration,although the consumption of biomass fuel and the total heat supply remain immutable,the total power generation can be increased by 2 803.04 MWh throughout the year,with an average annual solar-electricity efficiency of 16.16%.Besides,the levelized cost of electricity is 0.929 5 RMB/kWh,which is 15.50-28.50%lower than the traditional single solar thermal power plant.Then,a solar-assisted biomass-fired cogeneration system based on sludge drying is advised:the condensate heated by solar thermal energy drives the sludge drying,and the dried sludge is burned in the biomass boiler after mixed with biomass fuels,which helps increase the generation capacity of the plant.Through the hourly simulation of the system,aided power generation of 11 265.02 MWh can be obtained throughout the year with an additional power generated efficiency of 28.02%after adopting this integration scheme.The performance of the system increases as the moisture content of wet sludge and dried sludge decreases,and as the co-firing proportion increases.Moreover,the levelized cost of electricity is only 0.496 8 RMB/kWh.According to the principle of "energy counterparts and cascade utilization",the solar thermal energy and biomass plant are coupled in an efficient and flexible way to reduce the phenomenon of "waste light",improve the utilization of solar energy,and increase the recycling stabilized and harmless disposal of urban sludge.And at the same time,the dual purposes of increasing power generation to improve economic benefit and saving energy to protect the environment are achieved.The results show that this two integration solutions have the advantages of flexible operation mode,increased power generation efficiency,and improved utilization efficiency ’of renewable energy.They not only meet the needs of our country to vigorously develop solar energy and reduce its investment costs,but also provide new ideas for solving urban sludge pollution. |
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