Study Of The Design And Application Of Graphite Based High-temperature Sensible Heat Thermal Storage System For Heating Supply

As one of the important technologies for realizing green and clean energy utilization,under the background of"carbon peaking and carbon neutralization",energy storage technology has great strategic significance for China’s energy technology revolution.As one of the important ways of energy storage technologies,heat storage technology is an important application,which have prospect and academic significance for heat supply enterprises,especially in the match of energy supply and demand.In this research,the actual heating demand of a typical heating station in urban central heating is taken as the object,and the system design of graphite high temperature sensible heat storage system is studied,which participate in heating of power stations and the heat supply operation state.The research achievements are committed to systematically mastering the operation characteristics,which is based on the graphite high temperature sensible heat storage in the heat supply system.The research has provided theoretical and engineering guidance for the application of the graphite high temperature sensible heat storage system.In this research,according to the energy consumption and actual installation conditions of a thermal power station,graphite is used as the solid sensible heat storage material,and the arrangement of embedded series parallel heating tubes is adopted to realize the adjustment of the heat exchange area in the temperature zone at both ends.A single unit with a volume of 1.15×0.45×1.32 m~3,with a mass of 1182 kg,is designed and manufactured.The heat storage capacity 6.64×10~8 J between the available working temperature range from 220℃to 620℃.And designed discharging power is about 70k W.Five modules are used to form a graphite high temperature sensible heat supply system with a maximum heating power of 350 k W and a heat release time of 2.5 hours.Secondly,by designing and building a heating performance test-bed based on five parallel graphite heat storage modules,the heat storage and release performance and the output characteristics of the heating system are studied.According to the secondary heating temperature and flow rate determined by the experiment,the heat storage and heat release performance of a single module is studied firstly.The results show that the heat release fluctuates greatly and the output power cannot reach the target load under the single module primary pipeline compensation mode.On this basis,the heating characteristics of the operation mode of three module combined heating are studied.The results show that the heat release mode with multiple modules can match the target load,but it will cause fluctuations in the temperature and power of secondary heating,making the output temperature of the system deviate from the appropriate temperature range for heating at a certain time.Further research is carried out by connecting buffer water tanks with different capacities on the secondary side to study the impact on the heating output power characteristics.The results show that adding 0.3 t buffer water tank at the secondary outlet can effectively reduce the secondary temperature fluctuation by more than 60%and keep the heat supply in an appropriate stable range.The conclusion of operation configuration scheme of heat storage system matching the actual heating demand is obtained through experimental research.Finally,on the basis of the research conclusions of this paper,based on the actual needs of thermoelectric coupling,grid peak shaving,energy conservation and emission reduction in the heating production and operation of Beijing District Heating Group Co.,LTD.,the research and prospect of suitable scenarios based on graphite high-temperature sensible heat storage system are carried out.