Design Of Waste Heat Thermoelectric Power Generation System For Small Oil-Fired Boiler

With the rapid development of modern science and technology,people have continuously studied the boiler flue gas waste heat recovery technology.The use of semiconductor thermoelectric power generation technology can effectively recover the waste heat of the boiler and improve the efficiency of energy use^[1].This thesis combines the boiler waste heat and thermoelectric power generation technology to design a small fuel oil boiler waste heat thermoelectric power generation system,so that the small fuel oil boiler flue gas waste heat can be used more effectively.The research contents are as follows:First of all,this thesis designs a thermoelectric power generation system.By using four groups of thermoelectric power generation sheets,they are arranged according to the temperature gradient and attached to the outside of the boiler flue.In the high temperature area,four thermoelectric power generation chips are connected in series,and then one thermoelectric power generation chip is added for power generation in each group.Due to the influence of external temperature changes,the output power of each group of thermoelectric power generation chips is unstable.In this thesis,the maximum power point tracking algorithm of disturbance observation method is used to maximize the output power of the distributed thermoelectric power generation chips.Then,the four groups of thermoelectric power generation chips are output to the DC-DC converters respectively.Aiming at the problem that four groups of DC-DC converters are directly connected in parallel,the efficiency of the converter will be reduced.In this system,the non-isolated four-switch synchronous buck-boost working DC-DC converter is used and designed the maximum current automatic current sharing circuit,so that the voltage output by the four groups of DC-DC converters to the load is equal.Finally,the entire small fuel oil boiler waste heat thermoelectric power generation system was tested.The experimental result proves that the thermoelectric power generation chip array of the waste heat thermoelectric power generation system of the small fuel oil boiler can output at the maximum power point.In addition,the DC-DC converter also achieves the effect of current sharing,and the conversion efficiency can reach more than 85%.