(381a) Application of a Synthesis and Design Methodology Incorporating Process Intensification

In recent years, Process Intensification (PI) has attracted considerable academic interest as a potential means of process improvement, to meet the increasing demands for sustainable production. PI aims to benefit processes without sacrificing product quality by increasing efficiency, reducing energy consumption, costs, volume, and waste as well as improving safety. A variety of intensified operations and equipment has been developed in academia and industry. Potentially, this creates a large number of options to improve the process but to date only a limited number have achieved implementation in industry, such as reactive distillation, dividing wall columns and reverse flow reactors [1].

Some of the reasons for this are that the currently available methods for design and synthesis for process intensification to find the set of feasible solutions within which the optimal can be found are neither simple nor systematic and take considerable resources. Hence, a process synthesis tool to achieve PI would potentially assist in the generation and evaluation of PI options. This leads to the development of a general PI synthesis and design methodology in which redundant intensified options are systematically removed by checking against predefined constraints through a decomposition approach of the optimization problem where the lower level steps employ simple and easy calculations, while the higher level steps employ more rigorous and detailed calculations. Such a methodology is reliant on a set of tools as well as structured knowledge, which is provided in this work through retrieval from a computer-aided knowledge base where relevant information obtained through a literature survey is classified in terms of known intensified processes and the principles on which the intensification are based, different methods for achieving PI and the tools employed to achieve them.

In this contribution the developed systematic methodology together with supporting methods and tools is applied to improve a production plant of hydrogen peroxide. Different steps of this process have been under investigation for improvement using PI equipment previously [2,3] but a systematic generation and comparison of different PI options to improve the design has not been tackled to date and this is therefore seen as a good example. Starting point is a base-case design of a cyclic anthraquinone process [4,5]. It comprises the catalytic hydrogenation of an anthraquinone solution [6] in a fixed-bed reactor [7], followed by oxidization of the hydrogenated solution with air in a bubble-column reactor [8] to produce hydrogen peroxide. Hydrogen peroxide is separated via extraction with water and further purified through distillation to achieve a concentration of 70 wt.% while the working solution is recycled back to the hydrogenation reactor [4,5].

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