Ammonia is a common substance found in the wastewater generated from oil refining and coal chemical processes. It is convenient and economical to recover the ammonia from these waste water streams and use the ammonia as the absorbent to treat gaseous pollutants. The synthesis of ammonia from hydrogen-containing tail gases or directly from coal is also an option for ammonia sourcing.
Coal-based Ammonia Synthesis Technology
Raw gas produced in coal gasification is processed through the water-gas shift reaction, the Rectisol process, and methanation to produce synthesis gas. Synthesis gas is compressed and fed into the ammonia synthesis unit to produce anhydrous ammonia, which is stored in ammonia storage tanks. Vent gas from the storage tanks is also recycled to the system.
Ammonia Recovery From Sour Water
A single-column pressurized process is used for sour water stripping. The process schematic diagram is shown in the following figure.
Ammonia Recovery from Coal Gasification Waste Water
The coal gasification process generates a large amount of waste water that contains a high-concentration of pollutants. JNEP has developed a unique process to recover phenol and ammonia from coal gasification waste water. The process flow is shown in the following figure.
Ammonia Synthesis from Hydrogen-containing Tail Gases
Purge gases from many chemical processes often contain hydrogen at relatively high concentration. Hydrogen is purified by pressure swing absorption (PSA) and mixed with nitrogen to synthesize ammonia.
Multiple ammonia sourcing solutions that meet client’s ammonia supply requirements;
Environmentally friendly processes that removing pollutants by utilizing recovered ammonia from other waste streams
A further reduction in the operating cost of the EADS process due to a stable, cost-effective ammonia supply.
Anhydrous ammonia: NH3 ≥ 99.6%, residual ≤ 0.4% (Meets GB 536-88 Standard)
Aqueous ammonia: NH3: 20-28%, phenol & sulfides ≤ 10 ppm