Lg Chem, Ltd

Seok Hwan Choi

Kyoung Su Ha

Boo Gon Woo

Seong Pil Kang

Young Bae Kim

Jun Seok Ko

Sang Youn Lee

Jun-Seok Ko

Kyoung-Su Ha

Geon Yong Kim

Min Jeong Park

Koo Hyun Kang

Disclosed is a shell-and-tube heat exchanger type reactor that can be used for a process of producing unsaturated acids from olefins via fixed-bed catalytic partial oxidation, which comprises at least one reaction tube, each including at least one first-step catalyst layer, in which olefins are oxidized by a first-step catalyst to mainly produce unsaturated aldehydes, and at least two second-step catalyst layers, in which the unsaturated aldehydes are oxidized by a second-step catalyst to produce unsaturated acids, wherein a first catalyst layer of the second-step catalyst layers, disposed right adjacent to the first-step catalyst layer, has an activity corresponding to 5&#x2dc;30% of the activity of the catalyst layer having a highest activity among the second-step catalyst layers. A method of producing unsaturated acids from olefins by using the reactor is also disclosed.

Method of producing unsaturated acid from olefin

Disclosed is a method for producing (meth)acrylic acid comprising a process of recovering (meth)acrylic acid as aqueous (meth)acrylic acid solution from a (meth)acrylic acid-containing gas mixture produced by the catalytic gas phase oxidation of at least one reactant selected from the group consisting of propane, propylene, isobutylene and (meth)acrolein, wherein the recovering process comprises the steps of: (1) feeding the (meth)acrylic acid-containing gas mixture into a quenching tower and condensing it in the quenching tower so as to recover an aqueous (meth)acrylic acid solution from the bottom of the quenching tower, in which some of the recovered aqueous (meth)acrylic acid solution is recycled to the upper portion of the quenching tower so as to condense the (meth)acrylic acid-containing gas mixture; (2) passing the uncondensed part of the (meth)acrylic acid-containing gas mixture from the top of the quenching tower to a distillation tower; and (3) heating the bottom of the distillation tower to separate water-containing impurity components from the uncondensed (meth)acrylic acid-containing gas mixture and to discharge them from the top of the distillation tower. A system used for carrying out the method is also disclosed.

Method for producing (meth) acrylic acid

Disclosed is a simplified method for recovering acrylic acid from a mixture containing acrylic acid, acrylic acid dimer and impurities with high boiling point, in a stable and efficient manner. The method comprises the steps of: introducing the mixture into an acrylic acid recovering device comprising an acrylic distillation unit integrated with an acrylic acid dimer pyrolysis tank; carrying out decomposition of acrylic acid dimmer under reduced pressure and recovering acrylic acid. The method optionally further comprises a step of recycling a portion of the solution obtained from the bottom of the acrylic acid recovering device to the acrylic acid recovering device.

Method for recovering acrylic acid

Disclosed is a process for producing unsaturated aldehydes and/or unsaturated acids from olefins or alkanes in a fixed bed shell-and-tube heat exchanger-type reactor by catalytic vapor phase oxidation. A heat exchanger-type reactor for use in such a process is also disclosed. The process utilizes at least one first-step reaction zone and a second-step reaction zone that is divided into two or more shell spaces by at least one partition. The process may be applied to a single-step process for producing unsaturated acids from alkanes or alkenes.

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

Disclosed is a temperature measuring device. The temperature measuring device includes: a thermo-well tube; and a cable or wire type temperature measuring means which is installed in a thermo-well tube, wherein temperature measuring means has temperature detecting sensors disposed at an intermediate portion thereof, and the temperature detecting sensors can be moved axially in the thermo-well tube by applying tension to both ends of the cable or wire type temperature measuring means. The present invention also provides a reaction tube in which the temperature measuring device is disposed axially, and a reactor including at least one temperature measuring device or reaction tube as described above.

Temperature measuring device

The present invention relates to a method for producing (meth)acrylic acid comprising a process of recovering (meth)acrylic acid as an aqueous (meth)acrylic acid from a (meth) acrylic acid-containing gas mixture produced by the catalytic gas phase oxidation of at least one reactant selected from the group consisting of propane, propylene, isobutylene and (meth) acrolein, and a system usable for the method.

The present invention provides a process of producing unsaturated aldehydes and unsaturated acids from olefins by fixed-bed catalytic partial oxidation in a shell-and-tube heat exchanger-type reactor. In this process, the reactor comprises a first-step reaction zone of mainly producing the unsaturated aldehydes, a second-step reaction zone of mainly producing the unsaturated acids, or both the two zones. The first-step reaction zone is divided into two or more zones by a partition. Each of the divided shell spaces is filled with a heat transfer medium, and the heat transfer medium in each shell space is maintained at isothermal temperature or a temperature difference of 0-5&#xb0; C. The temperatures of the heat transfer media in each of the divided shell spaces are set to increase in the moving direction of reactants. In order to facilitate the removal of heat generation at a location where the partition is placed, a reaction inhibition layer is disposed in the first-step reaction zone. Also, in order to protect the catalyst layer from a highly exothermic reaction, the process is performed at a limited temperature difference between the temperature in a hot spot and the temperature of a molten salt. If the improved heat control system according to the present invention is used, the heat stability of the catalyst layer will be secured and the yields of intermediate and final products can be increased.

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Daejeon, South Korea

Seok Hwan Choi