Research On Fundamental Theory And 3D Cycle Construction Method Of Thermodynamic Adsorption Carbon Pump

The effects of fatal climate change on human survival have already been recognized,hence,the CO₂ emission reduction has attracted attention.In the current research stage,the CO₂ capture technologies are regarded with application potential.The CO₂ adsorption capture has the advantage of low energy consumption,no equipment corrosion,and easy controllability.Consequently,the CO₂ adsorption capture was primarily focused in this study,the concept of thermodynamic adsorption carbon pump（TACP）was proposed.The heat pump has been researched in the classical thermodynamics field,in which the mechanism of conversion between different forms of energy can be clarified.In this study,the possible application of classical concepts,tools,and methods of thermodynamics in the research of CO₂adsorption capture was considered.Four aspects,including the fundamental concepts,ideal cycle,actual cycle,and experiment,were considered in the TACP research.In the aspect of fundamental concepts,both the definition and fundamental assumptions of thermodynamic carbon pump were concerned,the thermodynamic carbon pump model was proposed.In the aspects of the cycle,the construction of TACP two-dimensional（2D）/three-dimensional（3D）ideal cycle and the 3D actual cycle was completed,the energy consumption and efficiency assessment on TACP can be achieved then.In the aspect of the experiment,the temperature swing adsorption CO₂capture system was established,the cyclic performance of the system was evaluated by the experimental study,which can be regarded as the practical application of the TACP model.Details are as follows:In the aspect of fundamental concepts,the thermodynamic carbon pump was proposed as the analogy of the heat pump.The CO₂ capture process was depicted as the CO₂ enrichment process from the low CO₂ concentration carbon source to the high CO₂ concentration carbon source,which is driven by the energy input.The thermodynamic carbon pump model was proposed as the analogy of the heat pump model.The finite-and infinite-mass capacity thermodynamic carbon pump models were defined,respectively,for the ideal energy consumption calculation of CO₂capture technologies.The energy-related performance indicators,including the ideal specific energy consumption,coefficient of CO₂ capture performance,and thermodynamic second law efficiency,were defined.The compatibility,ideality,and practicability of the thermodynamic carbon pump model were demonstrated in case studies.In the aspect of the ideal cycle,the TACP 2D ideal cycle was constructed as the analogy of the heat pump ideal cycle.Based on the assumption of constant temperature,the TACP 2D ideal cycle was established in the coordinates of chemical potential and molar amount（μ-n）.Considering that the temperature variation cannot be neglected in the actual adsorption CO₂ capture technologies,the temperature was determined as the third coordinate,the TACP 3D ideal cycle was established in such a3D coordinate system（μ-n-T）.Furthermore,the energy conversion in each of the processes of the ideal cycle can be obtained separately,by which the ideal energy consumption of CO₂ adsorption capture technologies was calculated.In the aspect of the actual cycle,the extended application of Gibbs’Thermodynamic Graphical Method was realized.The adsorbed CO₂ was regarded as the cyclic working fluid,and the gaseous-adsorbed phase thermodynamic equilibrium system was researched.With the determination of the thermophysical properties of the adsorbed CO₂,the 3D thermodynamic surface of the adsorbed CO₂ can be depicted in the coordinates of the adsorbed phase internal energy,entropy,and molar amount（U_a-S_a-q_e）.Furthermore,with the restriction of the 3D thermodynamic surface,the TACP3D actual cycle can be established by using the ideal process to connect the thermodynamic equilibrium points.In the aspect of the experiment,the cyclic performance of the temperature swing adsorption CO₂ capture system was evaluated.While using zeolite 13X as the adsorbent,the experiment results show that the thermodynamic second law efficiency of such a device range between 18.5%and 33.6%.The temperatures and the inlet gas CO₂ concentration were proved as the necessary parameters,a lower adsorption temperature and an appropriate desorption temperature would be recommended,and the pretreatment of the inlet gas would also be suitable for the improvement of the cyclic performance.In summary,the fundamental theory of TACP was preliminarily discussed in this study,the construction method of TACP cycles was proposed.The energy consumption and efficiency of CO₂ adsorption capture technologies were evaluated in a uniform standard from the thermodynamic perspective.