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Role of Chemical Reaction Engineering in Sustainable Process Development* (Addendum CHE 505) by C. Tunca, P. A. Ramachandran and M.P. Dudukovic Chemical Reaction Engineering Laboratory (CREL), Washington University, St. Louis, MO

Role of Chemical Reaction Engineering in Sustainable Process Development* by C. Tunca, P. A. Ramachandran and M.P. Dudukovic Chemical Reaction Engineering Laboratory(CREL), Washington University, St. Louis, MO

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Introduction Achieving sustainable processes, that allow us at present to fully meet our needs

without impairing the ability of future generations to do so, is an important goal for current and future engineers. In production of new materials, chemicals, and

pharmaceuticals sustainable processes certainly require the most efficient useof raw materials and energy, preferably from renewable sources, and prevention of generation and release of toxic materials. Advancing the state of the art of chemical reaction engineering (CRE) is the key element needed for development of such environmentally friendly and sustainable chemical processes. Current chemical processes depend heavily on the non-renewable fossil-based raw materials.These processes are unsustainable in the long run. In order to make them sustainable, chemical technologies must focus on employing renewable raw materials as well as preventing and minimizing pollution at the source rather than dealing with endof-pipe treatments. New technologies of higher material and energy efficiency offer the best hope for minimization and prevention of pollution. To implementnew technologies, a multidisciplinary taskforce is needed. This effort involves chemical engineers together with environmental engineers and chemists since they are predominantly in charge of designing novel chemical technologies. Pollution prevention problem can be attacked via a hierarchical approach based on three levels as outlined in the book by Allen and Rosselot1. Each level uses a systemboundary for the analysis. The top level, (the macro-level) is the largest system boundary covering the whole manufacturing activity from raw material extraction to product use and eventually disposal. These activities involve chemical and physical transformation of
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Chapter submitted to Sustainable Engineering Principles book.

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raw materials creating pollution or wastes as shownschematically in Figure 1. The scope of the macro-level analysis is mainly in tracking these transformations, identifying the causes of pollution and suggesting the reduction strategies. The next level is the plant level or the meso-scale which is the main domain of chemical engineers. The meso-level focuses on an entire chemical plant, and deals with the associated chemical and physical transformationsof non-renewable resources (e.g. petroleum and coal, etc.) and renewable resources (e.g. plants and animals) into a variety of specific products. These transformations can result in a number of undesirable The

products which, if not checked, can result in pollution of the environment.

challenge then for modern chemical engineers is to improve the efficiency of existing processes, to theextent possible, and design new cleaner and more efficient processes. While in the past the effort was focused on end of the pipe clean-up and remediation, the focus now is on pollution prevention and ultimately on sustainability. Mass and energy transfer calculations as well as optimization of processes that result in less pollution can be performed at this level. This plant scale boundary usuallyconsists of raw material pretreatment section, reactor section, and separation unit operations. (See Figure 2.) Although each of these sections are important, the chemical reactor forms the heart of the process and offers considerable scope for pollution prevention. The present paper

addresses the scope for pollution prevention in the reactor unit and sustainable development. It may however be...