Optimizing Ammonia Removal with Closed-Loop Stripping and Wet Gas Scrubbing System

Process Description

The initial position emphasizes the maximization of existing systems while utilizing a neutral liquid discharge (pH approximately 7). The installation is designed for the removal of ammonia from a liquid flow, typically at a rate of 15 tons per hour. The maximum liquid flow rate through the stripper is 19 tons per hour. The liquid introduced to the stripper operates at a temperature of 60 °C, with a minimum pH of 10.5.

Closed-Loop Air Circulation and Ammonia Absorption Using Wet Gas Scrubber

Approximately 16,000 m³/h of air is directed over the stripper through a fan. The air, which is laden with ammonia at the outlet of the stripper, is subsequently passed through a wet gas scrubber. A liquid is circulated over the scrubber, maintained at a pH of approximately 1.5 through the addition of sulfuric acid solution. The ammonia present in the gas stream is absorbed within the scrubber and converted into ammonium sulfate. At the outlet of the scrubber, the now nearly ammonia-free air stream is returned to the operational stripper via the fan. This air stream circulates in a closed loop between the operational stripper and the scrubber, facilitated by the fan.

Monitoring and Adjusting Ammonium Sulfate Concentration in the Scrubber Tank

The concentration of ammonium sulfate in the scrubber tank is monitored using a density meter located in the bypass of the pressure line. Once a specific concentration is detected, the processes of stripping and absorption are halted, and the ammonium sulfate solution is transferred to the storage tank. Subsequently, the scrubber tank is replenished with water, and sulfuric acid is added through a dosing pump to adjust the pH to approximately 1.5.