Patent ID: 8142742

Claim:
A shell-and-tube heat exchange reactor for producing unsaturated acids from olefins, the reactor comprising: at least one reaction tube; at least one shell; at least one first-step catalyst layer disposed in each reaction tube, wherein the first-step catalyst layer comprises a composite oxide which comprises molybdenum and bismuth, and which catalyzes the oxidation of olefins to produce unsaturated aldehydes; and at least two second-step catalyst layers disposed in each reaction tube, wherein each second-step catalyst layer comprises a composite oxide which comprises molybdenum and vanadium, and which catalyzes the oxidation of the unsaturated aldehydes to produce unsaturated acids, wherein a first catalyst layer of the at least two second- step catalyst layers is disposed directly adjacent to the at least one first-step catalyst layer, and the first catalyst layer of the at least two second-step catalyst layers has an activity of 5 to 30 percent of an activity among the at least two second-step catalyst layers, wherein the reactor further comprises a shell space, wherein the shell space is defined by the at least one reaction tube and the at least one shell, the shell space is divided axially by a first partition into at least two shells space portions, wherein a first shell space portion of the at least two shell space portions comprises a first portion corresponding to a first-step reaction zone which comprises the at least one first step catalyst layer, and a second shell space portion of the at least two shell space portions comprises a second portion corresponding to a second-step reaction zone which comprises a second catalyst layer of the at least two second-step catalyst layers, and the first catalyst layer of the at least two second-step catalyst layers is disposed in a portion of the at least one reaction tube which overlaps an entirety of a cross-section of the first partition.