You are tasked with completing the preliminary design of a plant for the production of dimethyl ether from methanol. This task involves a complete material and energy balance for the process, sizing the distillation columns, and optimizing the process based on economic and engineering considerations.
It is a preliminary process flow diagram (PFD) for the dimethyl ether production process. The raw material is methanol, which may be assumed to be pure. The feed plus recycle is pumped in P-201; heated, vaporized, and superheated in a heat exchanger (E-201); and then sent to the reactor (R-201) in which dimethyl ether (DME) is formed. The reaction that occurs is shown below. The reactor effluent is cooled and partially condensed in a heat exchanger (E-202), and it is then sent to the separation section. In T-201, "pure" DME is produced in the top stream (distillate), with methanol and water in the bottom stream (bottoms). In T-202, the distillate contains methanol for recycle, and the bottoms contains waste water. The desired dimethyl ether production rate is 100,000 ton/y.