An Insight into Investigations on Intensification of Adsorbent Beds

Many pollutants like acid gases, organic gases and inorganic gases are removed from gas mixtures by using adsorption. Regeneration of the adsorbent bed is an important aspect of successful adsorption technology. Adsorption-desorption cycle is governed by changes in pressure or temperature. These methods are termed as pressure swing (PSA) and temperature swing adsorption (TSA). For intensification of the process, it is envisaged to have an equal duration of the adsorption and desorption phases. Temperature swing adsorption (TSA) process can be intensified by employing several methods such as thermal conductivity promoter, thermoelectric elements and cyclic operating mode. Poor conductivity of the adsorbents is also one of the reasons for extended cycle time. Use of conducting materials in the form of composite fins for increasing the heat transfer through porous beds can reduce the adsorption-desorption cycle time. Also use of electrothermal swing adsorption (ESA) with thermoelectric element can intensify the adsorption-desorption process. Thermoelectric element converts current to temperature and vice versa. When there is difference in temperature, electric current of proportional magnitude is generated. Pressure swing (PSA) technology can also be intensified by using process engineering tools. Circulation fluidized beds can be used for dehumidification and also adsorption of volatile organic compounds (VOCs). Uniform bed temperature and mass transfer are advantages of circulation fluidized beds. In this paper, investigations on intensification of adsorption beds are discussed.