Enhanced Dehydration of Synthetic Gas Using Glycol Processes

Synthetic gas or syngas from gasification process of coal, petcoke, biomass and other carbonaceous compounds contains acidic gases that need to be removed. Being considered as state of the art process, amine absorption is widely used for this purpose. Although amine absorption eliminates almost 99% acid gas, this process however generates significant amount of water in the treated synthetic gas. Until today, no specific process was designed for removal of water from synthetic gas. This study aims to investigate the effectiveness of dehydration processes using glycol solution to remove water content in synthetic gas. Two gas dehydration
processes is used in this study, which are typical gas dehydration unit and stripping gas and Stahl column gas dehydration unit to represent enhanced gas dehydration. Enhanced dehydration process is a process equipped with some modification of regeneration part to obtain higher glycol purity once it has been recycled. From the simulation run by Aspen HYSYS, the results showed
that both typical gas dehydration unit and enhanced gas dehydration unit had successfully achieved the dehydration objective. These results are exhibited using phase envelope diagram of
gas stream exiting the dehydration unit. Besides, gas dehydration system using ethylene glycol
(MEG) also had reduced the water content of the synthetic gas down to the accepted level and meets the fuel specification.