Abstract The chemical process industry aims particularly at energy, capital expenditure and variable feedstock cost savings due to fierce global competition, the Kyoto Protocol and requirements for sustainable development. Increasingly conceptual process design methods are used in the industry to achieve these aims. They are used in: • existing processes to renew parts; • process re-designs based on existing feedstocks and catalysts; • innovative processes (new feed stocks, new catalysts, new process routes, new multifunctional equipment). This article is focused on the best industrial conceptual design practices applied for these application areas. To this end we have reviewed methods, which are used in the chemical process industry in the last 15 years. Capital, energy and variable cost savings are indicated for each method. Specific attention is paid to: • functional integration to multi-functional equipment; • heuristic based selection of unit operations and recycle structure; • superstructure based design optimisation with mixed-integer-non-linear programming (MINLP)
