Changing market conditions and production requirements in chemical and biochemical industry force engineers to depart from conventional plant design. Adaptability to the market demand, a reduced investment risk and a shorter time-to-market are gaining importance besides technical excellence. A reduced investment risk and an increased adaptability can be achieved by designing smaller plants and use step-wise capacity expansions. The use of modules offers the possibility to reduce the time-to-market. This work introduces an approach to determine the best expansion strategies for modular equipment-wise capacity expansions and compares its results to line-wise capacity expansion strategies and to a conventionally designed plant for a given market demand development using a detailed process simulation. In a case study, the modular equipment wise expansion strategy offers a 30% lower initial investment risk while increasing the absolute profit up to 40%, although the overall investment increased up to 40% compared to the conventional design. Additionally, an approach to design reactor modules with a larger operating window is proposed and compared in light of an equipment-wise capacity expansion strategy. Two final key statements to exploit the full potential of an equipment-wise capacity expansion are: (a) the determination of operating windows based on process-technological and mechanical operating constraints is a necessity and (b) equipment modules need to be designed for a large operating window to offer a capacity expansion by numbering-up without a gap in the operating window. (C) 2018 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.