Ammonium sulfate plant in Korea
Ammonium sulfate is a bulk crystalline product with a worldwide production of 17 million TPA. Most of the marketed ammonium sulfate derives from by-products of other processes. Ammonium sulfate is crystallized in Forced Circulation (FC), Draft Tube Baffle (DTB), and Oslo (also known as “Krystal”) crystallizers. FC units make a small particle, but are inexpensive and simple to operate. The Oslo can produce very large crystals, but it requires more process volume and which leads to higher capital costs. The DTB is the best compromise for large crystal size at lower investment, and most modern crystallizers producing ammonium sulfate are DTBs. This is due to large crystal and narrow size distribution produced by DTB crystallizers, which command a sizeable price premium. GEA Messo supplies all of the above crystallizers, (Download our brochure for more information) and can help in selecting the right type for a specific application.
The use of Oslo crystallizers has declined over the years, and in practice most Oslo crystallizers are operated as FC’s, producing a smaller crystal size then would be expected from a fluidized-bed crystallizer. Several of these units have been converted (by GEA Messo) to DTB crystallizers. GEA Messo provides evaluation services to ammonium sulfate producers, to analyze present operations and develop optimization strategies that target improvements in capacity, crystal size or both.
An expanding area in Ammonium Sulfate production is reaction crystallization of ammonium sulfate by neutralization of (spent) acid. Energy and investment savings are the driving force in reaction ammonium sulfate crystallization. GEA Messo’s reaction crystallization technology is applicable to both byproduct and pure chemical reactants.
Ammonium sulfate is also produced from flue-gas scrubbing solutions that contain ammonia (such as urea prilling tower exhaust scrubber effluent). The design of these crystallizers is influenced by the effect that urea has on the crystallization kinetics of Ammonium sulfate, and the need for high energy efficiency, due to the low feed concentration. Such crystallizers typically employ mechanical vapor recompression to reduce the energy cost.
Crystallization of ammonium sulfate usually occurs in solutions that include organic compounds as minor constituents. This environment leads to more complex crystallization operation, as the impurity concentration increases. Ammonium sulfate crystal growth and habit are very susceptible to the presence and amount of impurities in its growth environment. As a result, impurity presence and concentration will influence product crystal size and purity. GEA Messo maintains a modern Research Facility where custom-made solutions to such problems can be tested and refined, and effective methods to improve crystal size and purity can be developed for specific installations.