| The development of economy and technology cannot be separated from the development and utilization of energy.The global storage of abundant coal is widely distributed throughout the country as a long-term resource of China.The distribution of coal resources in China is widespread,but the distribution is uneven,resulting in the situation of coal supply insufficiently in some areas.The uneven distribution and insufficient transport capacity have led us to carry out coal blending technology to stabilize the boiler operation.Coal gasification slag have abundant SiO2,Al2O3,Fe2O3,which has certain volcanic activity and provides a choice for coal blending technology.In this paper,a 300MW circulating fluidized bed unit is used for the analysis and study of the mixing and drying of gasification slag based on the relevant theories of thermodynamics and technical economics.Boiler efficiency of different blending and drying,power generation coal consumption and economic benefits,we first analyze the influence of the thermal performance and economic performance,and blending and drying system calculation model is set up.Based on the calculation model,this article from the perspective of thermodynamics and economics,blending and drying system has carried on the detailed calculation and analysis,the results show that the three kinds of slag blending gasification solutions directly,using the knowledge of the thermodynamics and economics,blending gasification coarse slag have less effect on the composition of flue gas,flue gas flow only increased by 2.07%compared to the original unit,an air volume is only increased by 1.48%,the boiler efficiency is only 0.46%lower,the power generation coal consumption increases only 1.57 g/kWh,are less than mixed coarse slag and slag blending gasification.However,the economic benefits of mixed gasification residue scheme are even more significant.The cost of fuel economy is about 9896 million yuan,and the annual profit is RMB 30 million.On the basis of this,several schemes of drying gasification slag can be put forward,which have some energy saving effect and good economic benefit.In view of the insufficient contradiction and direct blending technology,this paper puts forward with raw coal gasification dry slag water control of blending and coarse slag fine slag drying five plan,after the systematic analysis and study found that the gasification slag drying to 25%,20%,15%and 20%respectively after the moisture content,although with the dry degree of deepening,system thermal performance is superior,but the energy consumption of drying and extraction amount needed are larger,drying equipment investment and operation maintenance cost are increased.Instead,due to the coarse slag water control fine slag drying scheme,only need a small amount of gasification fine slag drying,so its drying cost and operation maintenance costs are low,can save fuel cost about 10.8 thousand RMB an hour,annual profit of about 30.84 million yuan,has the very good economic performance.This article research results laid the foundation for a scientific theoretical basis to realize the design optimization of coal blending technology in China and run efficiently,point out the way forward for the power coal blending technology and thermal system of efficient integration. |
