Implementation of Heat Integration for Efficient Process Design of Direct Adipic Acid Synthesis in Flow

Abstract

Process-design intensification situated under the umbrella of Novel Process Windows heads for integrated and simplified smart-scaled (micro/meso) flow process design in a holistic picture. The example taken here is direct adipic acid synthesis which is an important intermediate for the nylon industry. To investigate its potential for process simplification cost and energy analysis is searched. Process simulation of the flow process with 40 %, 50 % and 98 % conversion is made. An energy efficient process is searched for this novel direct route in particular considering its heat integration for the three conversion cases. For this purpose pinch analysis is employed and a new heat exchanger network (HEN) is designed with minimum total annualized cost. The improvement of the HEN results in 50 - 70 % saving in operating cost which enables to pay back the extra capital cost requirement in less than one year in all cases. The benefit of heat integration is seen to be reduced with increased conversion due to the reduced heat load in the process. Another consideration here is the selection of the heat exchanger type. The pinch analysis is restricted to shell and tube heat exchangers, however by utilization of compact (including microchannel- based) heat exchangers additional benefits in terms of cost and plant complexity can be achieved.