Date of Award

Spring 2019

Degree Type



Chemical Engineering

Director of Thesis

Dr. Thomas Stanford

Second Reader

Dr. Kenneth Roberts


Gamecock Chemical Company has proposed the construction of a maleic anhydride plant at its Houston refinery. The plant is to produce 40,000 metric tons per year of maleic anhydride from a mixture of excess butanes. This design team has been asked to produce a conceptual design, simulation, and profitability analysis for the proposed plant. The simulation software Aspen Plus by AspenTech was the primary software used to design the plant, and the CAPCOST program in Microsoft suite’s Excel was utilized for the economic review of the process.

Maleic anhydride is produced by the thermal oxidation of n-butane at an elevated temperature and pressure, in this case 375°C and 20 bar. A catalyst, vanadium phosphorous oxide, assists in this reaction, adsorbing oxygen onto its surface to enable its reaction with n‑butane. The process begins by feeding the mixed butane stream through two distillation columns to achieve pure n-butane. This pure stream is mixed with oxygen in air and fed to the reactor. Maleic anhydride and several byproducts are produced from this reaction. The desired solid maleic anhydride is purified using a series of cyclones.

It is recommended, based on the profitability analysis, that this process not be pursued further. Although the maleic anhydride product is more profitable than the feed stream, the high annual utility cost of $39,100,000 causes a negative net present value for this process. The main utility cost originates from the cost of compressing the large amount of air flowing through the system. Therefore, if this process is redesigned, it is recommended to design a process that requires less air flow or a lower pressure. Based on the current design, however, it is not recommended to move forward with this process.

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