Research On Solid Thermal Storage Electric Boiler

Taking a 240 kW solid thermal storage boiler in Shijiazhuang as the research object,aiming at the problem of electric heating pipe damage existing in the boiler,through theoretical analysis,it is pointed out that the consistency of temperature drop of the regenerator in the process of boiler heat release can be achieved by ensuring the same inlet air velocity of each heat exchange channel,and the way of improving air distribution is put forward.To achieve uniform air supply and ensure the consistency of temperature drop of boiler regenerator.Firstly,the air distribution box of solid thermal storage boilers is improved by numerical simulation and experimental test,and the uniformity of air distribution box outlet flow before and after improvement is evaluated by CU value reflecting the flow uniformity of each heat transfer channel.The results show that the uniformity of multi-channel circulating air flow can be effectively improved by setting diversion plate for the distribution air box with very irregular structure.The CU value of the outlet air flow of the improved distribution air box is 66 % higher than that of the original one.The test results show that the temperature drop consistency of the regenerator of the improved solid thermal storage boiler has been significantly improved.CFD software was used to simulate the three-dimensional air distribution of the improved boiler,and the velocity field distribution in the boiler was obtained by calculation.Two-dimensional numerical simulation was carried out for the boiler air-equalizing chamber and heat-exchanging passage.The reasons for the damage of the boiler electric heating tube were analyzed.The problems related to the operation of the solid thermal storage boiler under the low-frequency operation of the circulating fan were analyzed.The critical value of the safe operation frequency of the circulating fan was determined to be 16 Hz,and the guarantee of solid thermal storage was put forward.Safe operation strategy of electric heating pipe of electric boiler.Considering the fact that it is difficult for the designer to guarantee the absolute equality of the inlet wind speed of each heat exchange channel,the relationship between the inlet wind speed deviation of each heat exchange channel and the temperature deviation of the regenerator is obtained by numerical simulation,and the accuracy of the relationship is verified by experiments.Under the experimental conditions,the maximum error of the two methods is less than 10 %.Using this formula,the temperature drop deviation at different points in the heat storage body can be predicted by measuring the inlet air velocity deviation of the heat exchange channel in the cold state.Through repeated experimental research on solid thermal storage boilers,the problem of electric heating pipe damage in the operation of solid thermal storage boilers is solved,which provides a useful reference for the development and use of solid thermal storage boilers.