SO2 is the major chemical causing acid rain. The traditional process uses sieve plate tower, which is huge with poor mass transfer efficiency and easy to be clogged. In a RPB, gas-liquid mass transfer between gas and absorbent is substantially enhanced. The size of the reactor is reduced substantially, which saves the capital and operating costs. The removal efficiency for SO2 can easily reach 99%.
Case 1
Two RPBs were installed in a sulfuric 
acid plant under Zhejiang Juhua Co., Ltd to process the tail gas. Since the startup in 2010, the SO2 emission has been consistently below the regulation level.
Operating conditions
| Total capacity (Nm3/hr) | 140,000 |
| Solvent | Ammonia |
| Inlet SO2 concentration (mg/m3) | 6,000 |
| Outlet SO2 concentration (mg/m3) | <200 |
Case 2
Three RPBs were installed in a sulfuric acid plant under SINOPEC Nanjing Chemical Industries Co., Ltd to process the tail gas. Since the startup in 2012, the SO2 emission has been consistently below the regulation level.
Operating conditions
| Total capacity (Nm3/hr) | 360,000 |
| Solvent | Ammonia |
| Inlet SO2 concentration (mg/m3) | 6,000 |
| Outlet SO2 concentration (mg/m3) | <200 |