| Waste minimization based on reactions is proposed as waste source-oriented design. The qualitative prediction of by-products in reactors is carried out by the knowledge base of reaction synthesis. Then the quantitative prediction of by-products based on equilibrium is analyzed and implemented with the automatic search and estimation of thermodynamic properties. The amount prediction of wastes provides possibility to find the optimal reaction conditions, that is, temperature, pressure and raw materials ratio, at which the waste index in products stream is at the minimum. The cases involving vinyl chloride production processes are employed in order to demonstrate the applicability of the program. By process analysis using commercial simulation software, the designed reactor is put into process flow chart and process information is obtained.; Concerning the total toxicity of industrial wastewater, the definition of toxicity of aquatic organic mixture solution is described. The simultaneous implementation of group contribution method and of molecular structure expression as a character string makes possible the machine prediction of toxicity of an organic compound. An industrial example, the balanced VCM production process is analyzed by the prediction method. Reducing by-products with high emission amount or with high toxicity results in great reduction of toxicity of wastewater. The predictable relationship of the water toxicity and the emission extent helps to find an efficient emission scheme.; Life Cycle Assessment (LCA) is an important idea to evaluate environmental effects when performing process or product design in chemical industry. While cost and profitability analysis is indispensably used to evaluate economic effects, LCA is scarcely used in the designs. Some of the main reasons are the difficulties in data availability and in applicability of methodologies. In the research, industrial emissions of chemical processes are related to the process blocks and can be estimated based on the knowledge of process flow chart. The weighting factors of environmental effects of chemicals can be also estimated based on the group contribution method. Those methods provide the availability of LCA data. Furthermore, examples are used to illustrate the application of the methods and the environmental impact index. |
