CRYOGENIC MULTIPLE BED BASED DEHYDRATION AND CO2 SEPARATION DURING PURIFICATION OF NATURAL GAS

A novel concept of separation of water and CO2 from natural gas is presented in this
work using multiple cryogenic packed beds. The principle separation of water and CO2
from natural gas is the difference in the desublimation of components in natural gas.
Experimentation is conducted based on dehydration and CO2 removal from natural gas
while simulation is carried out to validate the result. A series of pre cooled bed for
effective separation between water, CO2 and natural gas can be used periodically. The
dehydration unit is kept slightly below the freezing point of water which desublimates
water upon passing the wet gas and the remaining components do not undergo phase
change. The same concept is also applied for CO2 removal from natural gas using
cryogenic packed bed. It is worthy notable that CO2 undergoes phase change from gas to
solid and there is no chemical reaction involved. The 1-dimensional pseudo
homogeneous model is used to describe the process for desublimation of both water and
CO2. Furthermore, the concentration and temperature distribution during dehydration
and CO2 removal from natural gas at cryogenic temperature are investigated in detail.
The optimization of operating conditions of multiple cryogenic beds based on
dehydration and CO2 removal is analyzed. The resulting simulation shows the good
resemblance with the developed model.