PEP Review 93-2-3
Maleic Anhydride From n-butane; Fixed Bed Reactor; Organic Solvent Recovery
Published: February 1995
Considerable research continues to focus on the maleic anhydride process. In this review we show that the effort appears to be justified by potentially significant improvements in process economics. SRI's maleic anhydride Process Economics Report, 46C, issued in October 1989, evaluated fixed bed and fluid bed reactor systems used to produce maleic anhydride (MAN) from n-butane. It examined both systems, each using two methods of product recovery and purification--direct dehydration and organic solvent recovery.
This review presents the details of the fixed bed, organic solvent recovery process as a base case. We update the economics for this design from the 1989 report. The technical design basis remains the same. We believe that its reaction section represents the basic design of many current plants. We also believe, however, that future plants will most likely reflect a trend toward larger reactors. We compare this base with a design variation that includes the results of current process investigations. This variation considers the effect of the use of graded, shaped catalyst beds and continuous addition of alkyl phosphate catalyst promoters.
The economics for the process variation using graded shaped catalyst beds and alkyl phosphate addition are better than those of the base case. High catalyst productivities at low bulk densities are an advantage for the graded, shaped catalyst case as long as catalyst costs are not too high.