ammonia plant

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CHE655 - Plant Design Project #6 Summer 2011


(Courtesy of the Department of Chemical Engineering at West Virginia University)

Introduction You work for a consulting company that has been hired to determine a profitable operating condition (but not necessarily the most profitable) for an ammonia synthesis loop at your client's facility. You are only to evaluate the ammonia synthesis portion of a much larger process that takes coal, converts it into a synthesis gas (carbon monoxide and hydrogen), adds nitrogen and removes the carbon monoxide, adjusts the composition and produces ammonia. Ammonia is one of the five most produced chemicals in the industry. It is a raw material for nitrogen oxides and fertilizers, among others. The process in question is to produce 50,000 tonne/year of ammonia in an 8,000-hour year. Process Description A suggested process flow diagram (PFD) is shown in Figure 1. You should use this as a starting point. Your assignment is to develop a "profitable" case, where "profitable" is dependent upon economic considerations, i.e., EAOC. In reporting your best case, clearly indicate any modifications to the PFD and state the operating conditions for the modified process and the corresponding EAOC. However, you need not carry out any optimization in your process. Chemical Reaction Syngas is available from a pipeline at 1000 kPa and 200°C. It is compressed, mixed with a recycle stream, and heated or cooled to 350°C to be fed to the reactor. The reactor operates adiabatically. The reactor effluent is cooled, the pressure is reduced by a valve, and the stream partially condensed, producing an ammonia-rich stream. The ammonia liquid product is in Stream 8. Some of Stream 9 is recycled and some is purged. Depending on the pressure of the flash separator, V-601, the recycle stream may...