Process Study And Optimization Of Preparong Phthalic Anhydride From Naphthalene

This paper takes phthalic anhydride plant of Xuyang Group as an object, deeply studies the technological characteristics and production status of phthalic anhydride, finds and proposes the bottleneck problem of technical process and optimum proposal, and obtains a certain economic and social benefits.Technical study shows that the bottleneck problems of phthalic anhydride plant in Xuyang Group are mainly classified into:(1) The high-power power-equipment has a higher energy consumption, such as circulating water pump and cooling tower fan, etc.; (2) The effective availability of high pressure steam is lower, which causes energy waste; (3) Blockage in pipelines results in the decrease of the effectiveness of technical process; (4) The economical efficiency of tail gas controlling need to be improved.In terms of the bottleneck problems mentioned above, we systematicly study on the device layout and the features of technical process, and optimize the phthalic anhydride plant with the method of combining partial integration and individual optimization. It mainly includes:(1) Clear the operating points of key links and the optimal control area of technological parameter. (2) Conduct electric drag optimization of circulating water pump and cooling tower fan to make the air supplying system change from electric drag into steam turbine drag. The three individual optimizations save electric charge about 3.37 million yuan per year. (3) Make integrated utilization with steps towards by-product steam, and replace the whole heat source the system heating need by the steam produced from the reaction, which improve the using rate of by-product steam by a large margin. (4) Set the phthalic anhydride purification and product packaging together to decline carrying power and the steam consumption of heat preservation as well as reduce the probability of blockage in pipelines. (5) The process method of phthalic anhydride tail gas is changed from water scrubber to the incineration disposal of thermal storage, which reduces wastewater discharge but improves the efficiency of tail gas treatment. This transformation can increase profit about 3.18 million yuan per year.