Effect of feed nozzle configuration on n-butane to maleic anhydride yield: From lab scale to commercial

In the process to produce maleic anhydride via the partial oxidation of n-butane, selectivity is sensitive to feed gas configuration of both oxygen and n-butane. Based on laboratory scale fluidized bed experiments, selectivity was superior when the n-butane was co-fed together with oxygen. When the oxygen and n-butane were fed separately through a distributor and a sparger, selectivity was highest when the sparger was closest to the distributor (independent of whether the n-butane was fed through the sparger and the oxygen through the distributor or vice versa). Various feed gas configurations were tested in a 4.2 m diameter commercial circulating fluidized bed reactor equipped with 926 spargers at three different levels. Maleic acid production rate increased by about 15% when oxygen was fed to a lower sparger 0.45 m above the distributor compared to when it was fed at a height of 1.9 m. These observations indicate that maintaining the catalyst in an atmosphere containing oxygen is important for overall n-butane conversion and maleic anhydride selectivity.

Graphical abstractWe have studied the effect of several feed sparger configurations on the reactor performance in a lab scale fluidized bed as well as in the DuPont commercial CFB reactor for the production of maleic anhydride. In the commercial reactor, maleic acid production rate increased by about 15% when oxygen was switched to a lower sparger in the reactor. Sparger studies in the lab scale fluidized bed highlighted the importance of supplying sufficient oxygen to the reactor to improve the reaction yield by maintaining the catalyst in an oxidized state.Figure optionsDownload full-size imageDownload high-quality image (49 K)Download as PowerPoint slide