Research Of Evaporation&Crystallization Process Technology For Producing Ammonium Sulfate With Tail Gas Containing Ammonia

This paper is based on Daqing Refining and Chemical Company by-product ammonium sulfate project, which polyacrylamide ammonia tail gas was absorbed with dilute sulfuric acid to dilute ammonium sulfate25%, after evaporation, concentration, deposition, crystallization, centrifugal drying, to obtain the ammonium sulfate product. This is the domestic existing conventional by-product ammonium sulfate process,so ammonia tail gas can be thoroughly treated, at the same time, turning waste into treasure, the products of ammonium sulfate was exported as fertilizer.This paper mainly research the existing traditional evaporation and crystallization process of by-product ammonium sulfate process, tries to solve the problems of high energy consumption, low yield, poor quality of the evaporation concentration process in by-product ammonium sulfate technology, to improve the crystallization process and crystallization equipment to produce large particle ammonium sulfate, increase the product level, quality and added value and to get the significant social and economic benefits.The research of this paper is to improve the existing domestic evaporation process by analyzing and comparing by-product ammonium sulfate evaporation process in domestic and overseas, the original single effect evaporation process was changed to the three effect evaporation, and by calculating the flow through the software simulation, the three effect evaporation process and operation parameters were determined, thus solve the problems of original long process flow, high energy consumption, low yield,and second steam easy crystallization..The crystallization process research in this paper is based on the current situation and development trend of ammonium sulfate crystallization, by studying its crystallization principle, analyzing the factors affecting crystallization and the existing research results of various data, to improve the existing crystallization process, determine the crystallization operation parameters and liquid circulation methods, so as to determine the size structure of crystallizer, to produce large particle ammonium sulfate, improve the added value of products.In this paper, by comparing the ammonium sulfate drying process scheme, we determine the ammonium sulfate drying process route and decide to adopt disc drying process as well as to confirm the drying conditions and dryer specifications. In the end, we solve problems of long traditional air drying process, large energy consumption and high investment. This paper eventually formed a new complete by-product ammonium sulfate device software technology package, by improving the existing domestic by product technology of ammonium sulfate, using the basic chemical theory of industry, adopting the existing computer simulation software, through data analysis of the existing achievements and on-site data monitoring, testing for the improvement and optimization of ammonium sulfate evaporation, and apply it in the existing device improvement. Thus the by-product ammonium sulfate process steam consumption in single effect evaporation process is reduced from4.1t/t to1.27t/t, the yield increased from90%to99%of the original process, the ammonium sulfate product increased by the existing powder to an average particle size of1-3mm, the quality of the products reach the industrial superior grade, to improve product added value and fill the domestic blank in this field.