Abstract: 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 separa

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Disclosed is a structure for guiding the installation of a thermowell for temperature sensor, which is used to measure the axial temperature inside a fixed-bed catalyst reaction tube when it is filled with a catalyst, at a predetermined location in the reaction tube. In addition, a method for installing a thermowell for temperature sensor is provided. The method includes the steps of installing a structure for guiding the installation of a thermowell for temperature sensor in a reaction tube and fixing the thermowell for temperature sensor while filling the reaction tube with a catalyst.

Abstract: A heat exchange-type reactor includes a reaction chamber (1) having mounted therein a plurality of contact tubes (5) filled with a catalyst material; at least one shield plate (11) mounted within the reaction chamber to partition an inner space of the reaction chamber into at least two separate spaces (1d, 1e); a plurality of conduits (13, 15, 17, 19) having entrance (15a, 17a) and exit (13a, 17a) openings through which a heat transfer medium respectively enters and exits, and being mounted to an outer circumference of the reaction chamber (1) corresponding to the partitioned spaces (1d, 1e); and a heat exchange unit connected to the conduits (13, 15, 17, 19) to perform heat exchange of the heat transfer medium, in which the heat exchange unit includes a single heat exchanger that performs the exchange of heat of the heat transfer medium in accordance with the partitioned spaces.

Abstract: 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.

Abstract: The present invention provides a process of producing unsaturated acids from unsaturated aldehydes by fixed-bed catalytic partial oxidation in a shell-and-tube heat exchanger-type reactor, as well as a shell-and-tube heat exchanger-type reactor for use in the process. In the invention, second-stage reaction zone of mainly producing unsaturated acids by the catalytic vapor phase oxidation of an unsaturated aldehyde-containing gas mixture produced in a first-stage reaction zone with molecular oxygen is divided into two or more shell spaces by at least one 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° C. Also, in order to protect catalyst layers from a highly exothermic reaction, the process is performed at a limited temperature difference between the temperature at a hot spot and the temperature of the heat transfer medium.

Abstract: 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° 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.

Abstract: Disclosed is a structure for guiding the installation of a thermowell for temperature sensor, which is used to measure the axial temperature inside a fixed-bed catalyst reaction tube when it is filled with a catalyst, at a predetermined location in the reaction tube. In addition, a method for installing a thermowell for temperature sensor is provided. The method includes the steps of installing a structure for guiding the installation of a thermowell for temperature sensor in a reaction tube and fixing the thermowell for temperature sensor while filling the reaction tube with a catalyst.

Abstract: The present invention relates to a facility parts cleaning solution for the processing of (meth)acrylic acid and/or (meth)acrylic esters and a cleaning method using the cleaning solution. An aqueous cleaning composition comprising 5 to 50 wt % of at least one alkali metal hydroxide selected from the group consisting of sodium hydroxide and potassium hydroxide, 0.01 to 1 wt % of a water-soluble amino acid, 0.001 to 0.05 wt % of N,N?-methylene bisacrylamide, and 0.001 to 0.05 wt % of azobisisobutyronitrile is used to clean facility parts for manufacturing (meth)acrylic acid and/or (meth)acrylic esters in order to easily remove polymers and deposits.

Abstract: The present invention relates to a facility parts cleaning solution for the processing of (meth)acrylic acid and/or (meth)acrylic esters and a cleaning method using the cleaning solution. An aqueous cleaning composition comprising 5 to 50 wt % of at least one alkali metal hydroxide selected from the group consisting of sodium hydroxide and potassium hydroxide, 0.01 to 1 wt % of a water-soluble amino acid, 0.001 to 0.05 wt % of N,N?-methylene bisacrylamide, and 0.001 to 0.05 wt % of azobisisobutyronitrile is used to clean facility parts for manufacturing (meth)acrylic acid and/or (meth)acrylic esters in order to easily remove polymers and deposits.

Abstract: A heat exchange-type reactor includes a reaction chamber (1) having mounted therein a plurality of contact tubes (5) filled with a catalyst material; at least one shield plate (11) mounted within the reaction chamber to partition an inner space of the reaction chamber into at least two separate spaces (1d, 1e); a plurality of conduits (13, 15, 17, 19) having entrance (15a, 17a) and exit (13a, 17a) openings through which a heat transfer medium respectively enters and exits, and being mounted to an outer circumference of the reaction chamber (1) corresponding to the partitioned spaces (1d, 1e); and a heat exchange unit connected to the conduits (13, 15, 17, 19) to perform heat exchange of the heat transfer medium, in which the heat exchange unit includes a single heat exchanger that performs the exchange of heat of the heat transfer medium in accordance with the partitioned spaces.

Abstract: The present invention relates to a method for separation of gas constituents from a multicomponent gaseous mixture employing a hydrate promoter. The method for separation of gas constituents from a multicomponent gaseous mixture includes the steps of reacting an aqueous solution containing a hydrate promoter with a multicomponent gaseous mixture to form a gas hydrate condensed with the gas constituents of high gas hydrate forming power and dissociating a specific gas component from the gas hydrate. In accordance with the present invention, a specific gas component can be seperated from a multicomponent gaseous mixture under a pressure much lower than that of the prior art method, which makes possible its practical application in various industrial areas emitting exhaust gases.

Abstract: The present invention relates to a method for separation of gas constituents from a multicomponent gaseous mixture employing a hydrate promoter. The method for separation of gas constituents from a multicomponent gaseous mixture comprises the steps of reacting an aqueous solution containing a hydrate promoter with a multicomponent gaseous mixture to form a gas hydrate condensed with gas constituents of high gas hydrate forming power and dissociating a specific gas component from the gas hydrate. In accordance with the present invention, a specific gas component can be separated from a multicomponent gaseous mixture under a pressure much lower than that of the prior art method, which makes possible its practical application in various industrial areas emitting exhaust gases.