Optimized Research On Thermoelectric Power Generation Device For Natural Gas Decompression Station

Natural gas is an important energy sources in China currently.With the increase of its consumption,the distribution of natural gas pipelines is also increasing.The decompression station is a key device in the pipeline distribution system and is mainly used to monitor the gas flow and prevent the pressure in the distribution system from being too high.In order to meet the power demand of the decompression station,this paper applies the thermoelectric power generation technology to the heat collecting device for burning natural gas to provide stable electricity for decompression station equipments of the West-to-East Gas Transmission Project.Firstly,the simulation model and the performance test bench of thermoelectric power generator(TEG)are established.The influence of the boundary condition of the hot and cold side,the load resistance and the working current on the power generation performance is analyzed.Secondly,a model of thermoelectric power generation device is established in Fluent,and set up a test bench to verify its accuracy.By analyzing the influence of excess air coefficient,radiator,heat storage material and flue structure on the heat recovery rate of the device,the optimal design scheme is obtained.Finally,in order to optimize the output power of the TEG,the DC-DC converter is used to manage the direct current output by the TEG,and a simulation model in Simulink is built to study the effects of temperature difference,load and duty cycle on the efficiency of DC-DC converter and TEG output power.It is found that when the TEG hot side is at a constant heat flow,the larger the load,the larger the temperature gradient of the thermoelectric leg,and the best matching load is greater than the internal resistance of the TEG,and the output power increases first and then decreases with the cold side temperature drop;when the temperature difference between the two sides of TEG is constant,the load variation has little effect on the thermoelectric leg temperature gradient.Through the research on the thermoelectric power generation device,it is found that the heat recovery rate without heat storage is up to 73.1%,and the total thermoelectric conversion efficiency is 1.68%.By Discussing the DC-DC converter's management of TEG output DC power,it is found that the maximum output power tracking can be achieved by fine-tuning the duty cycle when the load is fixed.When the temperature of the hot side and cold side is fixed,the duty cycle corresponding to the maximum output power increases with the load.When the load and internal resistance are far apart,the DC-DC converter can obviously improve the power generation performance of the device,and the output power is increased by up to 81.62%.