Toward an environmentally sustainable natural gas-based ethylene production process through exergy-aided pinch analysis

This paper presents a case study on improving the energy integration of a gas-based ethylene process by focusing on major sources of thermal exergy losses. Exergy analysis is used to find the main sources of thermal exergetic inefficiency. Thermal solutions are then developed, leading to a comprehensive list of cold and hot process streams that could potentially reduce exergy losses from these sources. Pinch analysis is then carried out to screen these streams so only those, which can minimize the energy requirement, are maintained. Besides this, pinch analysis is used to select utilities and to explore cogeneration potential. Thus, the methodology used in this paper takes advantage of both exergy and pinch analyses, in a way that all the possible thermal solutions supported by exergy analysis are considered, preventing exclusion of any hot or cold process stream with high potential for heat integration during pinch analysis.