The Chemical Engineering Capstone class participates in Spring Term Design Day. The following Design Problem was worked for Spring 2018
Manufacturing Facility for Dimethyl Ether
In 2018, the AIChE Student Design Competition problem was to design a safe and sustainable chemical process to produce dimethyl ether (DME). DME is used as a chemical feedstock and also shows promise as an alternative transportation fuel. Because DME can be produced from natural organic wastes, it could reduce the transportation industry’s carbon footprint.
The US market for DME is expected to grow about 12% per year to $7.5 billion by 2022, motivating expansion of DME- production capacity.
This capstone design project required students to integrate a broad range of chemical engineering skills as they developed a process flowsheet; designed and costed the process equipment; incorporated strategies for heat and mass integration; conformed to environmental, health, and safety guidelines; developed mathematical models of major equipment; integrated multiple equipment models into a plant-wide process simulation using Aspen software; and then combined economic analysis with Aspen simulations to determine optimal plant operating conditions that maximized the plant’s profitability.
In solving this open-ended design problem, students were encouraged to incorporate creative design innovations while adhering to imposed constraints (e.g., safety guidelines and environmental regulations). All design specifications had to be justified. As in most real-world design projects, students were not given all the necessary information, so they had to do literature research, make (and verify) assumptions, and apply engineering heuristics (i.e., rules of thumb) to complete the design.
The example process flowsheet below shows how multiple unit operations (a chemical reactor, two distillation columns, and a compression system) could be integrated to convert methanol into DME and water, increase product yield using a recycle loop, purify DME and byproduct water streams via distillation, and compress DME vapor into a liquid DME product suitable as a diesel fuel replacement.