Study On Quantitative Environmental Impact Assessment In Chemical Process Synthesis

In this paper, current research achievements of quantitative environmental impactassessment are overviewed. On the basis of the research, a quantitative method-Chemical Green Index which was proposed by Prof. Yao Ke-jian is improved.Starting from the basic principle of process system design, the system can be divided into two parts: one is chemical process system; the other is energy generation system. The environmental impact of the chemical process system is classified eight categories: global warming potential, ozone layer depletion potential, acidification, photochemical oxidation or smog formation potential, eutrophication, aquatic ecotoxiciry, terrestrial ecotoxiciry and human toxiciry, every of which is evaluated equivalently. As to the energy generation system, taking coal combustion as an example, after combustion the main pollutants are analyzed in details, and then the environment impact is evaluated with the equivalent evaluation in the chemical process system. Finally, a total estimation is obtained after using the correlation related the two parts.Taking an ethanol refinery system of Anhui Fengyuan Biochemistry Co., Ltd. as an engineering instance, the Two Towers flow is simulated with the software -Aspen Plus of Aspen Technology. After analyzing the environmental impact with Chemical Green Index and EPS method, the result indicates that the energy consumed in the two towers is large fairly and the effects to the environment are large too. However after replacing by the double-effect refinery process, the environment impact is decreased evidently. The above instance indicates that Chemical Green Index is a good guidanceto optimize the chemical separation system.