For the Design of Chemical Process Equipment based on the book Product and Process Design Principles by Seider, Seader, Lewin and Widagdo. Often the design procedures for chemical equipment is hard to find and time consuming to apply. Therefore, I created functions which can be used to e.g. calculate the weight of a tower or shell and tube heat exchanger. Those weights are often required for Techno-Economic Assessments or Life Cycle Assessments