Research On Solar-Assisted Coal-Fired Power Generation System With Heat Storage Device

Promoting the healthy development of energy storage technology and industry is of great strategic significance for increasing the proportion of renewable energy,ensuring energy security,improving energy utilization efficiency and promoting energy revolution.The introduction of heat storage device into the solar auxiliary coal-fired power generation system solves the unbalanced relationship between the instability of solar energy and the continuous and stable generation of coal-fired power generation in terms of time and space,further promotes the utilization ratio of renewable energy and speeds up the pace of energy reform.In this paper,on the basis of a solar-assisted350 MW coal-fired power generation system,a heat storage device is introduced,and EBSILON software simulation platform is used to construct the thermal system model of the solar-assisted coal-fired power generation system for simulation calculation.Starting from the solar power generation side,this paper analyzes the factors influencing the thermal economy of the solar auxiliary coal-fired power generation system and seeks a method to maintain the constant temperature of circulating medium at the outlet of the solar collector.Results show that compared with the unit 1 and unit2,unit 3 run integrated way,heat consumption rate of thermal power plant,the steam consumption rate and standard coal burning rate of low,this integration method for economic best with the solar assisted heat device for coal storage system integration;To solve the problem of heat stress in the connection pipeline of oil-water heat exchanger,it is necessary to integrate the oil-water heat exchanger with the collector into the thermostatic storage tank,and use the control valve and flowmeter to regulate the amount of oil entering the oil-water heat exchanger.Starting from the side of the heat storage device,the maximum value of heat stored in the heat storage tank is the objective of the optimization function,and the diameter of the heat storage tank and the height of the heat storage material filled into the heat storage tank are the constraint conditions.MATLAB software PDE function was used to simulate the temperature field of heat transfer fluid and heat storage medium in the heat storage tank.Finally,the heat capacity of the heat storage tank and the number of the heat storage tank were designed using the subsection method.The results show that When the diameter-height ratio of the heat storage tank is 5/8.5,the heat storage reaches the maximum.From the analysis of temperature field stones: According to the analysis of the temperature field of the heat transfer fluid,it can be seen that some of the fluid entering the packed bed conducts convective heat transfer with pebbles,while the other fluid first fills the space between pebbles,and then conducts convective heat transfer with pebbles.When the heat storage time reaches about 300 min,the temperature of the heat transfer fluid remains unchanged,that is,the heat transfer stops,and the pebble temperature in the pebble packed bed reaches 270℃.According to the principle of "distribution according to demand",100 heat storage tanks are arranged in parallel between the oil-water heat exchanger and the heat collecting field at the side of the thermal device.For different working conditions the thermal efficiency and the technical efficiency analysis,the results showed that the working condition of 3(solar aided coalfired power generation system with heat storage device)working condition of coal than2(solar aided coal-fired power generation system)coal saving at least 7.62 t every day;he results showed that the working condition of 3 working condition of coal than 1 coal saving at least 26.28 t every day;The generation cost of solar-assisted coal-fired power system with heat storage device is 0.0006 yuan /k Wh lower than that of photovoltaic system without heat storage device.The unit further reduces pollutant emissions from thermal power units and improves the competitiveness of solar-assisted coal-fired power generation systems with heat storage devices in renewable energy generation.