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Based on the practice of urea synthesis system in No.1 urea plant of Urumqi Petro-chemical Co., this dissertation carries out some researches on two main processes in the synthesis system of urea, that is the process of synthesis and the process of stripping. The urea synthesis theory and the theory of chemical engineering systems are adopted. the synthesis process of urea is mainly affected by temperature, ammonia-carbon ratio, water-carbon ratio. It is also related to other factors, such as the holding time of mat-erial in the urea synthesis tower, impurity content in material, flow status of material, diathermancy and mass transfer coefficient between materials, uniformity of mix comp-osition of gas and liquid. The other process, stripping, is mainly influenced by varied factors, including operation pressure, stripping temperature, the gas-liquid ratio, holding time, liquid load.After application of the research in No.1 urea plant, the dissertation carries on so me contrast analysis and then proposes many improved measures aimed to production ac-tuality of the plant, such as decreasing farthest the water/carbon ratio, increasing the ammonia/carbon ratio, accelerating gas fluid contact in the synthesis tower and transfer of heat and mass by using siphon jet pumps trays, appending some system to dehydro-genate carbon dioxide, replacing 1% air by 0.3% pure oxygen to prevent the metal from corrosion, controlling equips under suitable loads and so on. The dissertation presents related theory for the operation and optimization of urea synthesis system, points out ac-tual improving direction, presents feasible measures, so it can offer an effective exa-mple and valuable reference for those similar equipments.
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