Novel concept of supporting the membrane separation of CO2 in power plants by thermoacoustic dehumidification

Highlights: • Moisture removal from exhaust gases is vital for efficient membrane separation. • Exhaust gases dehumidification might be performed using thermoacoustic cooling. • Application of designed installation in gas-fuelled units is specially advantageous. • Temperature of the gases and cooler efficiency influence the process parameters. -- Abstract: A high moisture content in exhaust gases adversely affects flue gas treatment – both with respect to particulate matter, as well as its gaseous compounds. Thus, the water vapor content in exhaust gases, especially in natural gas-fuelled units, might be a significant limitation preventing the widespread implementation of advanced flue gas treatment using membrane separation-based CO₂ capture. The negative impact of humidity on membrane separation processes is briefly discussed, basing on simple experimental investigation. This paper presents a method for accomplishing flue gas treatment via moisture condensation using process heat, based on the applying the thermoacoustic cooling phenomenon. Further computational analysis, which is devoted to the application of the indicated method in a gas turbine combined cycle unit based on both experimental and literature data, proves potential applicability of discussed method. The results of the investigation suggest appropriate parameters for flue gas dehumidification, using the presented method, as well as the areas, where further investigation and optimization are necessary.