A soap manufacturer located in Ontario supplies private label detergent products such as toilet bar soaps, liquid soaps and shampoos to major retailers in North America. The plant block diagram below illustrates the toilet bars soap making process at the company. The red boxes highlight the input raw materials for the process. The area within the blue dashed box illustrates the overall processing steps, and the green boxes are the outputs, including the final products. An important part of the business model is to properly account for all raw materials used in the manufacturing process when quoting production orders. Currently, a portion of the fat mixture (fat mix), a raw material, is included in the cost model but the amount in physical inventory was significantly less than what was shown in the inventory program, resulting in projected profit loss.
Jeffery Jackow, a University of Waterloo Chemical Engineering third year co-op student, worked in the Engineering Department. He was asked to collect the necessary data to complete a mass balance on the soap production plant to investigate this issue.
The teaching objective of this case is to illustrate the use of mass balances to quantify the efficiency of the soap making process.