In gas processing for natural gas, syngas or refinery gas, H2S has to be removed. However, CO2 is usually present, too. In a chemical absorption process, H2S can be selectively removed due to the faster reaction with the absorbent. A RPB is much superior to packed column for H2S selective removal. First, due to the intensification of mass transfer in a RPB, the reactor volume is dramatically reduced. Second, the selectivity is significantly increased since the residence time in a RPB is typically shorter compared to packed column and limited amount of CO2 is coabsorbed.
Case 1
A RPB was installed to replace the packed column in a refinery under Fujian Refining & Petrochemical Company Limited. The capacity is 8000 Nm3/hr and the solvent is MDEA. The comparison of performance between RPB and packed column is shown as below
.
RPB |
Packed column |
|
Height (m) |
2.9 |
32 |
Diameter (m) |
1.4 |
1.2 |
Reactor volume (m3) |
2.2 |
23.8 |
Packing volume (m3) |
0.31 |
14 |
Material |
Stainless steel |
Carbon steel for the shell and stainless steel for the packing |
H2S concentration after absorption (dry basis, mg/Nm3) |
<20 |
<20 |
Coabsorption rate of CO2 |
8.9% |
79.9% |