Location: Belgium
Start-up Time: Oct. 2014
Background:
A fertilizer factory adopted hot potassium basic solution in the first built de-CO2 unit, the process was replaced by MDEA method after scale-up revamping, however the CO2 content of outlet gas couldn’t meet the requirement, caused operation bottlenecks of ammonia plant. The user hoped that ZEHUA could optimal reform the absorber and regenerator to make the CO2 content of outlet gas meet the requirement, thus eliminate bottlenecks of ammonia plant.
Proposal:
(1) The original plastic packing was replaced by Ring-I metal random packing, to improve the efficiency of main packing.
(2) Cut the packing height down to ensure placing liquid redistributor among packing beds, what helped realizing uniform gas-liquid distribution.
(3) On account of the local flooding in existing unit, we replaced original bed limiter and packing support with new type ones.
(4) Improved the structure of feed distribute pipes and liquid distributors, eliminated local flooding and realized good distribution.
(5) On the premise of no welding to shell, applied special tower attachment to fix and support the new internals.
Result:
(1) When the capacity reached the maximum, the tested CO2 content of top outlet gas in absorber was only 17ppm, lower than the qualification of 100ppm.
(2) The old low concentration of amine liquid was still used instead of new high one, also the temperature of lean amine and semi-lean amine was higher than before, however the amine solution consumption was decreased by 7%.