Maleic Anhydride from n-Butane by the Boc/Mitsubishi Technology

BOC Gases and Mitsubishi Chemical have developed a new technology to produce maleic anhydride (MAN) from n-butane. The process is based on Mitsubishi s oxidation catalyst and uses a selective hydrocarbon separation technology (PETROX) developed by BOC Gases. The PETROX system recovers and recycles unreacted butane and allows the maleic anhydride to be produced at low butane conversion, maximizing selectivity and overall process yield. In addition, by injecting oxygen into the reactor feed, the process reduces the volume of air needed for the reaction and leads to savings in equipment costs. The technology has been successfully demonstrated in a large scale pilot at Mitsubishi Chemical s Mizushima facility, and is currently being offered for license. In this review, we present a technical and economic evaluation of the BOC/Mitsubishi process, based on the production of 66 million lb/yr (33,000 t/yr) of MAN at a U.S. Gulf Coast location. We also compare the economics of the process with those of conventional single-pass technology using a fluidized bed reactor. We conclude that the total fixed capital investment for a MAN plant using the butane recycle/oxygen injection concept is significantly lower than that required for the same plant using conventional technology. The estimated product value for the BOC/Mitsubishi process is also competitive, despite the additional cost of oxygen injection and the lower credit for steam generation. The technology would be most competitive at sites where butane costs are relatively high, compared to utility costs.