Adsorption equipment liquid phase process

There are many methods for the desulfurization of nature gas, which can be classified into dry desulfurization, wet desulfurization, and catalytic adsorption. In the dry desulfurization, some solid sorbents, such as iron oxide, zinc oxide, activated carbon (AC), zeolites, and molecular sieves, are used. In wet desulfurization method, liquid-phase chemical/physical solvent absorption systems are usually used for scrubbing H2S amine-based processes are subject to equipment corrosion, foaming, amine-solution degradation, and evaporation, and require extensive wastewater treatment. As a result, this sulfur removal technology is complex and capital intensive,44 although the processes are still employed widely in the industry. The desulfurization of coal gasification gas will be reviewed in detail in Section 5.5. In the catalytic-adsorption method, the sulfur compounds are transformed into H2S by catalytic HDS or into elemental sulfur or SOx by selective catalytic oxidation (SCO), and then, the reformed H2S and SOx are removed by the subsequent adsorption. 

A change in temperature alone is not used in commercial processes because there is no mechanism for removing the adsorbate from the adsorption equipment once desorption from the internal pores has occurred. Passage of a hot purge gas, or steam, through the equipment to sweep out the desorbed species is almost always used in conjunction with the increase in temperature. This is the case for both gas and liquid phase adsorption processes. For liquid phase separations the liquid is drained from the adsorption equipment prior to the passage of hot gas. 

Most mass transfer equipments consist of gas (vapor) and liquid two-phase flow, for instance, vapor-liquid two-phase cross-current flow is undertaken in tray distillation column gas-liquid two-phase countercurrent flow is taken place in packed absorption column. Some processes may also include solid phase, such as adsorption or catalytic reaction. Thus, the fluid system may contain gas and liquid two phases, or gas, liquid single phase besides solid phase. 

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