The widespread use of modularization at the process plant layout and design is mainly limited by the lack of uniform and generally accepted modular structures and approaches. A modular concept is presented that covers the modules definition, their identification, three-dimensional design, storage, and know-how assurance, with the aim of engineering- and equipment-reuse, plant layout and design as well as cost estimation with reusable modules. Finally, the modularization of mini-plants and the introduction of modularization in the teaching is considered.