Environmental Impact Assessment of Chemical Process Using the Green Degree Method

Abstract

Achieving sustainable development while limiting environmental pollution is one of the main enormous challenges for chemical engineering at present. To develop and design a greener alternative to replace or retrofit a current polluted process, it is essential to establish a method for quantitatively evaluating the environmental impact of a chemical process so that its environmental performance can be improved by identifying and discovering the bottlenecks that cause the pollution. In this work, a green degree (GD) method is proposed to quantitatively evaluate the environmental impact of a chemical process and related energygeneration system. Definitions and calculation formulas of green degrees for a substance, a mixture, a stream, and a unit (process) are illustrated. The green degree is an integrated index that includes nine environmental impact categories (including global, air, water, and toxicological effects). Therefore, it is comprehensive for assessing and understanding the environmental performance of a complex multicomponent chemical system. Three illustrative case studies are presented to further describe and verify the applicability of the method: (1) solvent screening by comparing the green degree values of solvents, (2) process route screening for producing methyl methacrylate (MMA), and (3) green degree analysis of the methyl methacrylate process (i-C4 route) by integration with process simulation technology.

Analysis of dual fluidized bed gasification integrated system with liquid fuel and electricity products

“…Green degree of a substance (GD Su k ) appearing in this study refers to the Zhang's work [19] which is listed in Table 3.…”

“…The flows of energy contained in each stream are summarized by using energy flow method, which gives a better understanding of heat loss and energy efficiency. Moreover, green degree method [19] is brought into this work to evaluate the environment impact of the system, nine environmental impact categories are considered in this method, which can give a comprehensive evaluate result of each unit and whole system. This work not only aims at presenting a detailed description including materials/energy flow and environmental influence of this integrated system, but also provides some suggestions for the improvement of DFB reactor when it is used for producing both liquid fuel and electricity products.…”

Process Analysis and Multi‐Objective Optimization of Ionic Liquid‐Containing Acetonitrile Process to Produce 1,3‐Butadiene

“…Currently, much literature is available to evaluate and discuss the performance of chemical processes for one or more environmental indices. Recently, a typical aggregation method, named the green degree (GD), was proposed by Zhang et al [35]. Based on this theory, every process can be considered as a system, which would influence the environment through the exchange of material and energy with the environment.…”

Green process for methacrolein separation with ionic liquids in the production of methyl methacrylate

“…The main advantage is that it applies the principle of mathematical solution approach but simplifies the problem through thermodynamic insights. 27,28 The unit values of green degree for the material are listed out in Supporting Information Table S3.…”

“…Because we mainly care about the effect of organics volatilization and energy consumption to the environment, the method in literature [28][29][30] was simplified in calculation in this work. The green degree of a process can be calculated from the following equations.…”