Partial Oxidation of o-Xylene to Phthalic Anhydride in a Structured Fixed Bed Containing a Sequence of Catalysts

Optimal Policies of Operation of a Fixed-Bed Reactor for Oxidation of o-Xylene into Phthalic Anhydride

“…Using the same cooling method, Bucala et al (1997) present the optimal shape of the temperature profile for the process of oxidation of ethylene into ethylene oxide. Varying the catalyst activity along the bed by means of changing the number of active sites, or simple dilution of the bed with inert particles (Caldwell and Calderbank, 1969;Sadhukan and Petersen, 1976;Pirkle and Wachs, 1987;Kotter et al, 1991), a suitable technological regime can also be achieved. Pirkle and Wachs (1987) have investigated the process of oxidation of o-xylene into phthalic anhydride using a mathematical model and have determined that a lower activity of the catalyst in the front of the bed results in a more stable operation of the reactor.…”

Alternative Reaction Engineering Concepts in Partial Oxidations on Oxidic Catalysts

“…4b (9). Once more, the influence of different reactions on reactor selectivity depends on the local composition of the gas phase.…”

“…The search for an optimal catalyst sequence was based on the strategy of biological evolution resulting in layers containing two to four different catalysts. Typical results, summarized from (9), are shown in Table 1. The analysis Figure 4: Reaction network of the partial oxidation of (A) isobutene to methacrylic acid (18) and (B) o-xylene to phthalic anhydride adapted from (9).…”

“…Alternative reactor concepts are, therefore, proposed and tested in cases, where selectivities and yields are more modest, such as the partial oxidation of n-butane to maleic anhydride (8) or of o-xylene to phthalic anhydride (9).…”