Thermodynamic analysis of adsorption carbon capture from limiting cycle to heat pump assisted cycle

Abstract

Carbon capture technology has drawn much attention due to its potential on decarbonization in industries. However, there are still gaps between thermodynamic analysis and real operation process, which make it difficult for theoretical analysis of complex carbon capture system. This paper evaluates the performance of real cycle based on real process, and a carbon capture system integrated with heating and cooling are proposed to explore the energy saving strategies. Three physical adsorbents and one chemical adsorbent are evaluated and compared in terms of working capacity and heat consumption on three adsorption cycles. The results show that Mg-MOF-74 performs the best among the adsorbents due to its excellent adsorption capacity. When adsorption temperature is 25 °C, the minimum heat consumption is 2.14 GJ t−1 at desorption temperature of 129 °C. The absorption chiller is introduced to reduce adsorption temperature for increase of working capacity. Zeolite 13X with a lower adsorption heat performs better than Mg-MOF-74. And the minimum waste heat consumption is 6.02 GJ t−1 at adsorption temperature of 10 °C and desorption temperature of 105 °C, which is lower than 6.39 GJ t−1 of the reference case. When total waste heat is specified, the performance of the system can be improved significantly if around 20 % is supplied to absorption chiller. The results indicate the potential of absorption chiller and absorption heat transformer in adsorption carbon capture and find that the shifts of operation temperatures to low temperature region are beneficial for energy saving of carbon capture system.