Numerical Simulation And Optimization Of Thermal Regenerative Adsorption Bed For Benchmarking Analysis Of Energy Efficiency

CO₂ adsorption technology,especially temperature swing adsorption（TSA）,is an important and effective method to reduce carbon dioxide emissions and achieve carbon neutrality.In recent years,however,the development of this technology has been hindered by high energy consumption.Standardization analysis and uniformity quantification of energy consumption of existing TSA system are carried out.Based on the internal heat and mass transfer mechanism of the system,optimizing the design of the part with high energy consumption is an effective way to improve the energy efficiency of TSA system.Based on energy efficiency benchmarking analysis method and numerical simulation method,optimization strategy of TSA system,especially adsorption bed energy efficiency is studied in this paper.First,based on the principle of thermodynamics,this study proposes a benchmarking analysis framework for evaluating the energy efficiency of carbon capture technology.The boundary and elements for the benchmarking framework are defined.Then,the specific heat consumption,coefficient of CO₂capture performance,and exergy efficiency are calculated as indicators for the benchmarking analysis using a general calculation method.Then,benchmarking analysis of energy efficiency performance data of TSA system in a large number of literatures are conducted and previous research is used to classify energy consumption into three TSA boundary levels:adsorbent,adsorption chamber,and adsorption system.Then,the influence of adsorption temperature and desorption partial pressure on energy efficiency are analyzed based on the self-coded TSA simulation program,which demonstrate the feasibility and fairness of the benchmarking analysis method.Finally,the ways to obtain standard data for the proposed benchmarking analysis via experimental methods are discussed.The proposed method can be used to guide the current design of TSA-based carbon capture technology toward optimal energy efficiency.Subsequently,according to the energy consumption benchmarking analysis,the adsorption bed is the highest energy consumption part of TSA system.Therefore,the introduction of internal heat exchanger（single-tube/three-tube）in the traditional adsorption bed is an effective technology to improve energy efficiency and heat and mass transfer.Under the same surface area,heat transfer area,total amount of adsorbent,operation pressure and inlet flow rate,the thermal design schemes including inlet speed,porosity and adsorption/desorption temperature based on single-tube/three-tube heat exchanger in adsorption bed are discussed.The results show that the three-tube heat exchanger is superior to the single-tube heat exchanger in energy efficiency performance under the same conditions.With the increase of inlet speed and porosity,the Coefficient of Performance of CO₂Capture of the three-tube heat exchanger increased by 5.9%and 1.4%,respectively,and the specific energy consumption decreased by 8.5%and 5.4%,respectively.Decreasing of adsorption temperature,increasing of desorption temperature result in the improvement of the separation and energy-efficiency performance in adsorption bed.The findings are beneficial to optimize the geometric structure and operation strategy of the adsorption bed in TSA system.Finally,in order to further verify the feasibility and reliability of the simulation results,the performance of the laboratory level adsorption bed with the same specification,size and geometry design is compared and optimized with that of the numerical simulation bed.Based on the experimental data,the influence of the introduction of heat exchanger on the structural performance of the adsorption bed and the influence of related factors on the efficiency performance of TSA are further illustrated.The double-tube heat exchanger adsorption bed under the experimental model and the single-tube/three-tube heat exchanger adsorption bed under the simulation model agree with each other and show some regular energy efficiency results,indicating that simulation can guide engineering design to a certain extent at the present stage.