Study Of Solar Ammonia-based Thermochemical Energy Storage System

Solar thermal power generation can be combined with a very economical energy storage system,which not only has high economic feasibility,but also overcomes the gap between solar energy gaps and provides a continuous energy supply.Thermochemical energy storage performs endothermic and exothermic cycles through reversible thermochemical reactions.It has the advantages of high energy density,low energy loss,and low storage temperature.The ammonia-based thermochemical energy storage system（amino thermochemical energy storage system）is considered to be one of the most promising systems because it has no side reactions and can be stored at room temperature.However,at present,there are very few studies on the amino thermochemical energy storage system in China,especially the research on the reactor in the solar amino thermochemical energy storage system.Based on the above background,with the support of the National Natural Science Foundation of China（Project No.51806194）,the research topic of this article was established.In this paper,a two-dimensional quasi-homogeneous model is established for the exothermic reactor and endothermic reactor in the solar amino thermochemical energy storage system,and the model is verified in combination with existing experimental data.Using this reactor model,an autothermal synthesis reactor（AHRR）system was proposed,and an optimized design was made for the system Ⅰ proposed by Chen et al.It has laid a certain foundation for the industrialization of the system and the wide application of green energy.This article starts from the aspects of ammonia synthesis reactor,ammonia synthesis system and system optimization.The main conclusions are as follows:（1）Aiming at the synthesis ammonia reactor（exothermic reactor）and ammonia decomposition reactor（endothermic reactor）in the solar amino thermochemical energy storage system combined with specific theoretical analysis,a two-dimensional quasi-homogeneous CFD numerical model of the reactor was established.There are experimental data to verify the correctness of the model;（2）Using the self-heating regenerative reactor（AHRR）ammonia synthesis system to improve and optimize the system Ⅰ proposed by Chen et al.Compared with the system Ⅰ,the reactor length required for AHRR is 44%of the system Ⅰ;The catalyst volume is reduced by 56%compared to System I;（3）The AHRR system was discussed,and the optimal diameter D₃ corresponding to the minimum V_w value of the AHRR reactor was determined by parameter analysis.The results show that the pressure drop ΔP_c in the catalyst bed increases with the decrease of the reactor diameter D₃,resulting in an increase in the required pumping power.Therefore,reducing V_w by reducing the thickness of the catalyst bed（reducing the diameter D₃）is somewhat Time is worth the money.Reducing the AHRR diameter（D₁ and D₅）can reduce the material cost of the reactor,increasing the mass flow of s CO₂ to enhance heat transfer can reduce the wall volume per unit power in the AHRR reactor,thereby reducing the cost of the reactor.