Industrial Ammonia Synthesis The Rectisol And Cryogenic Liquid Nitrogen Wash Process Analysis And Problem Solve

There are over 20 methods of desulfurization and decarbonization presently at home and abroad . Containing a large quantity of CO₂ H₂S CO and CH₄ and so forth in the feed gas of ammonia . the Rectisol Process , as a leading cold method with the lest energy consumption in physical absorption is introduced in the middle and small-sized ammonia plant with coal as the feed-stock.In the ammonia synthesis system . it is reasonable to apply purifying process, consisting of Rectisol and Liquid Nitrogen Wash .Since LNW needs to operate under the low temperature of absent minus 190℃, and the feed gas to LNW must be completely dried . Rectisol can not only dry the feed gas during washing , but reduce the gas temperature by minus 30℃ to minus 70℃,so that the power to freeze will be saved.Rectisol can remove various impurities from the raw gas .Under the low temperature condition between minus 30℃ and minus 70℃ . Methanol can remove these impurities from gas , such as H₂S COS CS₂ RSH C₄H₄S, CO₂ HCN NH₃ NO as well as paraffin hydrocarbon aromatic hydrocarbon and crude gasoline . In addition , it can remove water content from the gas , so as to dry considerably gas and to reduce impurities of CO CH₄ and Ar from feed-stock to LNW .As a result , the vent of purge gas from ammonia convertor in the synthesis system will be greatly increased , and a large amount of hydrogen will be saved . In the meanwhile ,the ratio of H₂ to N₂ 3:1 specified in syngas is also completed at the stage .During the operation , some problems are arisen in the Two Wash Units as follows :1. Inadequate cold flow of Rectisol ;2. Excessive CO content in the crude gas ;3. Higher water content of methanol in Rectisol ;4. Blockage in Rectisol System ;5. Higher consumption of methanol ;6. Higher naphtha content in the circulating methanol stream ;7. Inadequate cold flow of the cold box in NWU ;8. Increase in the resistance of gas channel in the cold box . Physical-chemical analysis has been made and solution to the above mentioned problems is put forward in this article in order to gradually increase the understanding of Rectisol and LNW Process , to ensure the steady operation of Rectisol and LNW Units during the production ,and to give full scope to the advantage economy and friendly environment of the two units .In addition to it , it will further increase the understanding of the design and calculation concerning Rectisol Unit ,and provide valuable technical data and operating experience for the technical reform of the middle and small-sized Chemical fertilizer Plant completely designed and made in China with lower cost . In the meanwhile , it will lay the firm foundation of increasing the competitive power of enterprise to the market .