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DESIGNING CHEMICAL PROCESSES WITH OPEN AND FUGITIVE EMISSIONS
Citation:
Smith*, R L., T. M. Mata, D M. Young*, AND C. V. Costa. DESIGNING CHEMICAL PROCESSES WITH OPEN AND FUGITIVE EMISSIONS. Presented at AIChE National Meeting, Reno, NV, 11/4-9/2001.
Description:
Designing a chemical process normally includes aspects of economic and environmental disciplines. In this work we describe methods to quickly and easily evaluate the conomics and potential environmental impacts of a process, with the hydrodealkylation of toluene as an example. The process economics of such a design have been described by Douglas (1988), and therefore our focus in on combining process economics with environmental costs and impacts. Of particular interest is a focus on the potential environmental impacts of open and fugitive emissions. To evaluate the potential environmental impacts of a process, the work of Young and Cabezas (1999) on the WAR algorithm is extended to include both open and fugitive emissions. The WAR algorithm uses a database of potential environmental impacts (including toxicity, acid rain, global warming, etc.) for 1600+ chemicals to evaluate streams that cross the system boundaries. While certain exit streams are known sources of waste, other sources come from leaks through valves, flanges, etc. This work studies the tradeoffs between economics and emissions, and also the environmental importance of fugitive versus open emissions.
Results of the study show the costs associated with environmental emissions due to material losses and wste handling. Thus, the conomics of environmentally friendly processes benefit from waste minimization. Depending on the process design either fugitive or open emissions can dominate the potential environmental impacts. Design alternatives are considered and evaluations of the economics and potential environmental impacts are presented. The results show that in some designs economics and environmental friendliness improve together, while other designs create tradeoffs between these objectives. In addition, the latest work refines fugitive emission rates and relates these rates to process designs through economic and environmental evaluations.