Method of producing unsaturated acid in fixed-bed catalytic partial oxidation reactor with high efficiency

Abstract

A shell-and-tube heat exchanger-type reactor including one or more catalytic tubes, each including a first-step reaction zone and a second-step reaction zone, wherein at least one of the first-step reaction zone and the second-step reaction zone is divided into two or more shell spaces by a partition; each of the divided shell spaces is independently heat-controlled; and a heat transfer medium having a temperature from the lowest active temperature of a catalyst layer in a reaction tube corresponding to the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone to the lowest active temperature of the catalyst layer plus 20° C.; and the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone is controlled so as to provide a reactant conversion contribution per length of 1.2˜2.5.

1 . A shell-and-tube heat exchanger-type reactor which can be used in a process for producing unsaturated aldehydes and unsaturated acids from olefins by fixed-bed catalytic partial oxidation, the reactor comprising one or more catalytic tubes each including a first-step reaction zone for mainly producing the unsaturated aldehydes, and a second-step reaction zone for mainly producing the unsaturated acids, or both the two zones, wherein at least one of the first-step reaction zone and the second-step reaction zone is divided into two or more shell spaces by at least one partition; each of the divided shell spaces is independently heat-controlled; a heat transfer medium in the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone has a temperature ranging from the lowest active temperature of a catalyst layer packed in a reaction tube corresponding to the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone to the lowest active temperature of the catalyst layer plus 20° C., wherein the two or more shell spaces corresponding to the first-step reaction zone are sequentially referred to as the first shell space of the first-step reaction zone, the second shell space of the first-step reaction zone, . . . , the n th  shell space of the first-step reaction zone, and the two or more shell spaces corresponding to the second-step reaction zone are sequentially referred to as the first shell space of the second-step reaction zone, the second shell space of the second-step reaction zone, . . . , the n th  shell space of the second-step reaction zone; and the first shell space of the first-step reaction zone or the first shell space of the second-step reaction zone is controlled in such a manner that it provides a reactant conversion contribution per length as defined in a following equation of 1.2˜2.5:
   Olefin conversion contribution per length=(mole number of olefins that have reacted in the relevant catalyst layer zone/mole number of the total olefins supplied to the first-step reaction zone)/volumetric ratio of the relevant catalyst layer zone to the total first-step catalyst layer of the first-step reaction zone, or     Unsaturated aldehyde conversion contribution per length=(mole number of unsaturated aldehydes that have reacted in the relevant catalyst layer zone/mole number of the total unsaturated aldehydes supplied to the second-step reaction zone)/volumetric ratio of the relevant catalyst layer zone to the total catalyst layer of the second-step reaction zone.   
     
     
         2 . A shell-and-tube heat exchanger-type reactor which can be used in a process for producing unsaturated acids from alkanes by fixed-bed catalytic partial oxidation, the reactor comprising one or more catalytic tubes each including a reaction zone for producing the unsaturated acids, wherein the reaction zone is divided into two or more shell spaces by at least one partition; each of the divided shell spaces is independently heat-controlled; a heat transfer medium in the first shell space has a temperature ranging from the lowest active temperature of a catalyst layer packed in a reaction tube corresponding to the first shell space to the lowest active temperature of the catalyst layer plus 20° C.], wherein the two or more shell spaces are sequentially referred to as the first shell space, the second shell space, . . . , the n th  shell space; and the first shell space is controlled in such a manner that it provides an alkane conversion contribution per length as defined in a following equation of 1.2˜2.5:
   alkane conversion contribution per length=(mole number of alkanes that have reacted in the relevant catalyst layer zone/mole number of the total alkanes supplied to the reaction zone)/volumetric ratio of the relevant catalyst layer zone to the total catalyst layer of the reaction zone.   
     
     
         3 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein the first-step reaction zone is for producing (meth)acrolein from at least one compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol, methyl-t-butyl ether and o-xylene. 
     
     
         4 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein the second-step reaction zone is for producing (meth)acrylic acid from (meth)acrolein. 
     
     
         5 . The shell-and-tube heat exchanger-type reactor according to  claim 2 , which is for producing (meth)acrylic acid from propane or isobutane. 
     
     
         6 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein the partition dividing the first shell space from the second shell space is disposed in such a manner that the first shell space covers a temperature peak generated in a front portion of each reaction zone. 
     
     
         7 . The shell-and-tube heat exchanger-type reactor according to  claim 6 , wherein the partition dividing the first shell space from the second shell space is disposed in a position corresponding to 25%˜50% of the axial length of each reaction zone. 
     
     
         8 . The shell-and-tube heat exchanger-type reactor according to  claim 2 , wherein the partition dividing the first shell space from the second shell space is disposed in such a manner that the first shell space covers a temperature peak generated in a front portion of each reaction zone. 
     
     
         9 . The shell-and-tube heat exchanger-type reactor according to  claim 8 , wherein the partition dividing the first shell space from the second shell space is disposed in a position corresponding to 25%˜50% of the axial length of each reaction zone. 
     
     
         10 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein the first shell space of the first-step reaction zone, the second shell space of the first-step reaction zone, . . . the n th  shell space of the first-step reaction zone, divided by the partitions are controlled in such a manner that temperature of the heat transfer medium circulating in each shell space increases along the axial direction. 
     
     
         11 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein the second shell space of the second-step reaction zone through the n th  shell space of the second-step reaction zone divided by the partitions are controlled in such a manner that temperature of the heat transfer medium circulating in each shell space increases along the axial direction. 
     
     
         12 . The shell-and-tube heat exchanger-type reactor according to  claim 2 , wherein the first shell space, the second shell space, . . . , the n th  shell space divided by the partitions are controlled in such a manner that temperature of the heat transfer medium circulating in each shell space increases along the axial direction. 
     
     
         13 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein T h1 −T salt1 ≦150° C., and T hN −T saltN ≦120° C. in the first-step reaction zone for producing unsaturated aldehydes from olefins (wherein N is an integer of 2 or more; T h1  is the highest peak temperature of a reaction mixture in a catalyst layer corresponding to the first shell space; T hN  is the highest peak temperature of a reaction mixture in a catalyst layer corresponding to the n th  shell space; T salt1  is the temperature of a heat transfer medium filled in the first shell space; and T saltN  is the temperature of a heat transfer medium filled in the n th  shell space. 
     
     
         14 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein T h1 −T salt1 ≦130° C., and T hN −T saltN ≦110° C. in the second-step reaction zone for producing unsaturated acids from unsaturated aldehydes (wherein N is an integer of 2 or more; T h1  is the highest peak temperature of a reaction mixture in a catalyst layer corresponding to the first shell space; T hN  is the highest peak temperature of a reaction mixture in a catalyst layer corresponding to the n th  shell space; T salt1  is the temperature of a heat transfer medium filled in the first shell space; and T saltN  is the temperature of a heat transfer medium filled in the n th  shell space. 
     
     
         15 . The shell-and-tube heat exchanger-type reactor according to  claim 2 , wherein T h1 −T salt1 ≦150° C., and T hN −T saltN ≦120° C. (wherein N is an integer of 2 or more; T h1  is the highest peak temperature of a reaction mixture in a catalyst layer corresponding to the first shell space; T hN  is the highest peak temperature of a reaction mixture in a catalyst layer corresponding to the n th  shell space; T salt1  is the temperature of a heat transfer medium filled in the first shell space; and T saltN  is the temperature of a heat transfer medium filled in the n th  shell space. 
     
     
         16 . The shell-and-tube heat exchanger-type reactor according to  claim 1 , wherein a reaction inhibition layer formed of an inactive material alone or a mixture of inactive materials and a catalyst is placed within the catalytic tube in a position corresponding to the position of the partition. 
     
     
         17 . The shell-and-tube heat exchanger-type reactor according to  claim 2 , wherein a reaction inhibition layer formed of an inactive material alone or a mixture of inactive materials and a catalyst is placed within the catalytic tube in a position corresponding to the position of the partition.