Feed gases: natural gas / dry gases / shift gas

The CO2 recovery process begins in the combustion furnace, where natural gas is burned, generating flue gas at approximately 300°C. This hot gas enters the washing tower and comes into contact with cooling water sprayed from the top, simultaneously cooling the gas and removing dust particles. The washing water, along with the captured solids, is discharged from the bottom of the tower and flows into a settling cooling pool for further separation of entrained particles.

The cooled gas, now at around 40°C, exits the top of the washing tower and is pressurized to 6kPa by a booster fan before entering the bottom of the CO2 absorption tower. Inside the absorption tower, a composite amine solution absorbs the CO2 component from the gas. The unabsorbed tail gas undergoes washing and cooling to 42°C, followed by the removal of any entrained solution using a demister. The treated tail gas is then safely released into the atmosphere. The washing liquid, after cooling, returns to an underground tank and is recirculated using a return liquid pump.

The CO2-rich solution, having reached equilibrium, is referred to as “rich liquid.” A rich liquid pump extracts this solution from the bottom of the absorption tower and pressurizes it before it enters the lean-rich liquid heater. The rich liquid is heated to 95-98°C and then sprayed into the regeneration tower through the top. Inside the tower, some components of the rich liquid decompose, releasing CO2 and water vapor. This mixture flows out from the top of the tower and enters the regeneration gas condenser, where it exchanges heat with cooling water before proceeding to the CO2 separator.

In the CO2 separator, any entrained mixed liquid is separated from the gas. The product CO2 is then pressurized by a compressor and directed to the desulfurization tower to remove impurities such as sulfur, NOx, and moisture. After sterilization and deodorization, the purified CO2 undergoes liquefaction in the liquefier before entering the purification tower for final refinement. The resulting purified CO2 achieves a purity of 99.99%, meeting food-grade standards.