Technical Renovation On Stripping Procedure Of Three-Pipe Channelization With Low Temperature In Bayer Process

With the development of the alumina production technology in recent years, Bayer technology and sintering technology are paid equal attention in process in Chinese industry. Stripping is the key production procedure in Bayer process,the production capacity and index good or bad have directly influence on production scale, production cost and quality. Combining with engineering practice,the key issues in technical renovation on stripping procedure of channelization with low temperature in Bayer process of Shandong Branch of China Aluminium Corporation are discussed.The reform of tube digestion process is focused on the production increasing and energy saving reformation of preheater, insulation cans, self evaporator and flash drums. Meanwhile, the supporting facilities such as slurry tank, feed pump, dilute trough, dilute pump and their automatic control systems are also accordingly reformed.Based on the thermal equilibrium calculation and industrial operation, the reformations on tube digestor are made, and the configuration and related technological data of the digestors are obtained.In order to improve the production outputs of the company, the reforms were made by prolonging the piping length and increasing heat tranfering areas to raise production capacity. After the technological reformations, as to the insulation system, the insulation time inceases and the A/S ratios in digesting liquids gets improved, which are of benefit to keeping production qualities;As for the selfevapotator system, the self evaporating areas are greatly inceased and the waste steam heat was fully used;With regard to flash drum system of exhausted steam, condensate is carried out by three times flash vaporization, and steam heat is more fully used,supplied with selfevaporator waste heat of condensate is made full use,which reduces the consumption of steam and improves economic benefits.Through the technical improvements and applying on the automatic control sysytems of the three-pipe tube digestion, the automatization and the operation of the whole system are improved and the work environment of the jockey are also ameliorated,which are helpful to stable production and optimization criterion.The engineering practice show that the ameliorated tube digestion process has obtained good effect in Bayer process application. It not only paves the way to the enlarge production of Shandong Branch of China Aluminium Cooperation, but also has great significance in reducing the cost of alumina production by low temperature Bayer process in the whole companies.