| This thesis applies systematic methodologies for quantitatively evaluating and improving the sustainability of chemical organizations and chemical processes. Through the following three case studies, we attempt to illustrate how green engineering tools enable an engineer to make more informed sustainability-based decisions through multiple organizational levels (a corporation, a chemical process, and a single unit operation):;• In Chapter 1, a fuzzy-logic based model is constructed to define and assess the overall sustainability of chemical corporations, primarily of Hanwha Chemical of Korea. Hanwha Chemical is evaluated to be "fairly sustainable" with respect to other companies in the diversified chemicals sector. A sensitivity analysis identifies reducing wastes to landfill and improving energy efficiency as two of its most critical sustainability targets.;• In Chapter 2, the energy efficiency of a grass-roots gas-to-liquids (GTL) process is assessed and improved via heat integration (pinch analysis). The integrated heat exchange network achieves 47% and 90% savings in capital and operating costs, respectively, through a 89% reduction in energy consumption.;• In Chapter 3, a life-cycle assessment (LCA) is performed on two process alternatives of power generation — an organic Rankine cycle (ORC) running on process waste heat versus coal-fired generation of electricity — to compare their life-cycle environmental footprint. Although the ORC option has an economic payback period of 3.3 years, its superior "environmental payback" of less than 3 weeks proves it to be the superior process option. |
