Study On New Solid Waste Resource Utilization System Integrated With Coal-fired Power Station

Since the reform and opening up,China’s economy has made remarkable achievements with sustained high-level,high-speed and high-quality development.With the increasing demand of Chinese people for a better life,the demand for domestic energy consumption is also increasing year by year.At present,China has become the world’s largest superpower in energy production,energy consumption and carbon emissions.With the acceleration of urbanization in China year by year,people’s solid waste in cities is also increasing.China has paid more attention to this huge challenge and made a positive response at home.For a long time,because China’s energy structure is dominated by coal,and it will also occupy a dominant position in the future,and oil and gas are highly dependent on foreign countries,the transformation of China’s clean and low-carbon energy is imminent.Based on this state and the situation of the authorities,the state pays more attention to energy conservation and efficient use of energy.The general secretary put forward the general policy of "peak carbon dioxide emissions,carbon neutrality" at the conference,so the collaborative integrated energy system of China’s power industry has received unprecedented attention,improving the efficiency of energy utilization.At the same time,the general secretary put forward that "green mountains and green hills are golden mountains and silver mountains",and we should treat our ecological environment as our relatives.With the increasing urban garbage,We need to explore how to "turn waste into treasure" to better solve the problem of environmental pollution caused by urban garbage accumulation,improve the power generation ratio and utilization efficiency of renewable energy and solid waste,and promote the process of social responsibility,energy conservation and environmental protection.Based on the above research background,this paper puts forward two new power generation systems that use municipal solid waste coupled with coal-fired generating units,namely,the anaerobic fermentation system of municipal solid waste coupled with coal-fired generating units,which burns the biogas generated by anaerobic fermentation in a biogas burner with high quality,and then inputs the high-energy flue gas generated by combustion into the steam-water cycle of coal-fired generating units;The plasma gasification system coupled with the coal-fired unit carries out plasma gas on the municipal solid waste in the plasma gasification furnace,and the combustible gas after plasma gasification is sent into the furnace for combustion through a special device;Both systems use modeling software to establish parameter change models and thermodynamic basis,supplemented by energy analysis,economic analysis,environmental analysis,etc,and systematically study the synergy mechanism and economic feasibility of the integration scheme.Firstly,a cogeneration system for generating biogas by anaerobic fermentation coupled with coal-fired units is proposed:the collected municipal solid waste is fermented in a fermentation tank at an appropriate temperature,and the biogas generated after fermentation enters a biogas tank for standby,and then is input into a biogas burner at an equal flow rate for high-temperature combustion;After the integration of the system,the energy input into the coal-fired unit remains unchanged,all of which are 1460MW,but the net power generation of the unit increases by 19.85 MW,and the net power generation efficiency in the coupled unit is as high as 43.72%.The average cost of electricity in the new system is 0.71 yuan/(kW·h).In a 25-year cycle,the integrated system of coal-fired unit and anaerobic fermentation to produce biogas can reach 615.9364 million yuan.Secondly,a cogeneration system for generating combustible synthesis gas by plasma gasification of municipal solid waste coupled with coal-fired units is proposed:the collected municipal solid waste is plasma-gasified in a plasma gasifier,and the gasified synthesis gas is purified by a purification device,so that the proportion of combustible gas in the synthesis gas is increased and the impurity gas is reduced,and then it is input into the boiler hearth of coal-fired units.After adopting the system integrated with the plasma gasifier,The net power generation in the system has increased by 20.58 MW,the net power generation efficiency in the system coupled with plasma gasification is as high as 42.38%,the net power generation efficiency of garbage power generation is as high as 42.98%,and the average power cost in the system is only 0.68 yuan/(kW·h).In its 25.36-year life cycle,the project can bring 645.9987 million yuan of net benefits to the coal-fired power station.Based on the principle of "energy matching and cascade utilization",we can realize the synergy between urban solid waste and coal-fired power station energy in a more flexible and efficient way,thus reducing the environmental pollution caused by improper solid waste treatment.This collaborative scheme can not only improve the utilization efficiency of solid waste,realize harmless disposal of solid waste and stable utilization of resources,but also increase power generation,save energy and reduce emissions,protect the environment and improve the economy of coal-fired units.This collaborative scheme has many advantages,such as flexible operation mode,high energy utilization efficiency and long-term stable income.The two forms of coupled cogeneration proposed in this paper not only bear the expectation of vigorously developing the transformation of coalfired units and reducing their investment and operation costs in China,but also provide a new idea for solving the environmental problem of "garbage siege" caused by the increasing solid waste in cities.