Design standardization of unit operations for reducing the capital intensity and cost of small‐scale chemical processes

A methodology is proposed to reduce the cost and capital intensity of small-scale chemical processes by creating new opportunities for economies of numbers through standardizing the equipment designs across multiple processes. We depart from asynchronous design of single-processes and adopt a common-functionality based simultaneous design of multiple processes that use similar unit operations. A generalized cost function is used to appropriately balance the trade-offs between economies of scale and economies of numbers. An optimization-based framework for design standardization is developed and illustrated using two case studies. The first involves the simultaneous synthesis of methanol and ammonia processes, and the second addresses the optimal synthesis of multi-column natural gas liquid (NGL) fractionation processes for different natural gas sources. We observe that considerable reduction in capital intensity of small-scale processes is possible through equipment standardization.