Abstract: The present invention provides a method for efficiently using an aqueous solution of (meth)acrylic acid at a low concentration formed in a production/storage step of (meth)acrylic acid. In the present invention, a (meth)acrylic acid derivative is produced by using as a raw material an aqueous solution of (meth)acrylic acid formed by one or both of: a device which reduces a pressure of a gas comprising (meth)acrylic acid in production of (meth)acrylic acid; and a device which collects (meth)acrylic acid from a gas comprising (meth)acrylic acid.

Abstract: A component measuring apparatus is provided with a case having a cylindrical case main body and a cover arranged to cover the base end opening section of the case main body; a chip mounting section for mounting a chip; a light measuring section for detecting a prescribed component; a printed board whereupon a control section having a function of controlling the operation of the light measuring section is arranged; a liquid crystal display device; a battery arranging section for arranging a battery provided on the cover; an O-ring arranged between the case main body and the light measuring section on the leading end section of the case main body; and an O-ring arranged between the case main body and the cover on the base end opening section of the case main body. Sealing of inside the case is ensured by the O-ring.

Abstract: A condenser includes: a top face of a tube plate on which acrylic acid may be condensed inside the condenser; a spray for spreading a polymerization inhibitor on the tube plate; a first polymerization inhibitor supply tube for supplying the polymerization inhibitor to the spray; and a supporter for supporting the spray at a predetermined position. The supporter supports the first polymerization inhibitor supply tube outside the condenser. The condenser allows a stable continuous operation for a long period of time by preventing polymerization of an easily polymerizable compound in the condenser into which a vapor of an easily polymerizable compound is supplied with a simple structure thereof.

Abstract: A component measuring apparatus is provided with a case having a cylindrical case main body and a cover arranged to cover the base end opening section of the case main body; a chip mounting section for mounting a chip; a light measuring section for detecting a prescribed component; a printed board whereupon a control section having a function of controlling the operation of the light measuring section is arranged; a liquid crystal display device; a battery arranging section for arranging a battery provided on the cover; an O-ring arranged between the case main body and the light measuring section on the leading end section of the case main body; and an O-ring arranged between the case main body and the cover on the base end opening section of the case main body. Sealing of inside the case is ensured by the O-ring.

Abstract: A method of storing (meth)acrylate in a tank of a less expensive and highly versatile material without losing stability of the stored (meth)acrylate. To be specific, a method of storing (meth)acrylate in a tank, including supplying an appropriate gas for storing (meth)acrylate into the tank, in which: the tank is made of a carbon steel material; the gas has a water concentration of 100 ppm or less; and the (meth)acrylate has a (meth)acrylic acid concentration of 30 ppm or less.

Abstract: (Meth)acrolein or (meth)acrylic acid is collected by bringing a reaction gas (1) containing (meth)acrolein or (meth)acrylic acid obtained through a vapor-phase catalytic oxidation reaction into contact with an aqueous solution as a collecting solvent in a collecting tower main body (2). The reaction gas (1) is supplied to the collecting tower main body (2) from two nozzles (2c) facing each other, and is caused to collide in the collecting tower main body (2). According to the present invention, (meth)acrolein or (meth)acrylic acid can be efficiently collected from a gas containing (meth)acrolein or (meth)acrylic acid while preventing polymerization.

Abstract: An object of the present invention is to provide a method for vapor phase catalytic oxidation which is almost free of variations in reaction states in respective reaction tubes of the fixed bed multi-tube heat-exchanger type reactor.

Abstract: A producing method of (meth)acrolein or (meth)acrylic acid where by use of a multi-tubular reactor that has a plurality of reaction tubes filled with a catalyst, catalytic gas phase oxidation of propylene, propane, isobutylene or (meth)acrolein is carried out in the presence of a composite oxide catalyst by use of molecular oxygen or a gas containing molecular oxygen, in which method (meth)acrolein or (meth)acrylic acid can be obtained stably in high yield for a long period of time without allowing the activity of the catalyst to decrease locally (disproportionately) and extremely. A temperature difference between a temperature of a heat medium at the beginning of operation and a peak temperature of the catalyst is set in a range of 20 to 80° C., and during operations a change of the peak temperature T of the catalyst in a tube axis direction is maintained in a definite range.

Abstract: The object of this invention is to provide a method of maintaining a multi-tubular reactor which can ensure the uniformity of states of reaction in the reaction tubes in the multi-tubular reactor. This invention is a method of maintaining a multi-tubular reactor in good condition by selecting a part of reaction tubes in a multi-tubular reactor at random, measuring a differential pressure occurring in each reaction tube when passing gas therethrough, separating any reaction tube showing an abnormal differential pressure as compared with the average of differential pressures in reaction tubes packed with an fresh catalyst of the same kind, giving adequate treatment to the separated reaction tube and returning it into the reactor with any other selected reaction tube falling within a normal range.

Abstract: An object of the invention is to provide a production method for (meth)acrolein or (meth)acrylic acid which can continue an operation without causing a decomposition reaction of acrolein or the like. According to the invention, provided is a production method for (meth)acrolein or (meth)acrylic acid, in which (meth)acrolein or (meth) acrylic acid is obtained by performing a catalytic gas phase oxidation on propylene, propane or isobutylene by using oxygen by means of a heat-exchange type multi-tubular reactor, having a tube bundle portion in which a multiple of reaction tubes each filled with a catalyst are aligned in parallel to one another and a tube plate which is adjacent to a downstream side of the tube bundle portion of the reaction tubes and forms a lead-out portion for a reaction gas, in which the tube bundle portion of the reaction tubes has a hollow-columnar constitution as a whole, and which is characterized in that a rectifier is provided on a tube plate.

Abstract: A decomposition reaction apparatus or distillation apparatus for acrylic acid in which a column bottom liquid heated in a reboiler (5) is supplied from a supply port (1a) provided on a side wall of a column body (1) having: a top plate (12a) above the supply port (1a); and an impingement plate (12b) provided vertically to the top plate (12a), for preventing scattering of the column bottom liquid to a supply direction. The top plate (12a) is provided such that the top face of the top plate (12a) is inclined downward from a base end to a tip end. The present invention allows: suppression of formation of a polymerized product due to flowing of a liquid or gas heated in a reboiler into a column with a simple structure; and a stable continuous operation of column equipment over a long period of time.

Abstract: A distillation apparatus for subjecting a crude readily polymerizable compound to distillation under vacuum conditions to purify it, the distillation apparatus having a distillation column and a vacuum generator and an exhaust gas conduit of the vacuum generator connected to a connecting conduit therebetween through a pressure control valve. A method provides purifying of a readily polymerizable compound by subjecting a crude readily polymerizable compound to distillation under vacuum conditions to purify it, the method including using a distillation apparatus having a distillation column and a vacuum generator and an exhaust gas conduit of the vacuum generator connected to a connecting conduit therebetween through a pressure control valve and controlling the action of the pressure control valve based on a pressure of the distillation column.

Abstract: A condenser includes: a top face of a tube plate on which acrylic acid may be condensed inside the condenser; a spray for spreading a polymerization inhibitor on the tube plate; a first polymerization inhibitor supply tube for supplying the polymerization inhibitor to the spray; and a supporter for supporting the spray at a predetermined position. The supporter supports the first polymerization inhibitor supply tube outside the condenser. The condenser allows a stable continuous operation for a long period of time by preventing polymerization of an easily polymerizable compound in the condenser into which a vapor of an easily polymerizable compound is supplied with a simple structure thereof.

Abstract: The object of this invention is to provide a method of maintaining a multi-tubular reactor which can ensure the uniformity of states of reaction in the reaction tubes in the multi-tubular reactor. This invention is a method of maintaining a multi-tubular reactor in good condition by selecting a part of reaction tubes in a multi-tubular reactor at random, measuring a differential pressure occurring in each reaction tube when passing gas therethrough, separating any reaction tube showing an abnormal differential pressure as compared with the average of differential pressures in reaction tubes packed with an fresh catalyst of the same kind, giving adequate treatment to the separated reaction tube and returning it into the reactor with any other selected reaction tube falling within a normal range.

Abstract: An object of the present invention is to provide a method for vapor phase catalytic oxidation which is almost free of variations in reaction states in respective reaction tubes of the fixed bed multi-tube heat-exchanger type reactor.

Abstract: A method for purifying a crude (meth)acrylic acid obtained by a vapor phase catalytic oxidation method, characterized in that the crude (meth)acrylic acid having most parts of water and acetic acid removed therefrom, is fed to and distilled in a first distillation column of a purification system comprising first to third three distillation columns, the top fraction from the first distillation column is fed to and distilled in the second distillation column, the resulting top fraction is recovered as a high purity (meth)acrylic acid product, the bottoms from the first and second distillation columns are fed to and distilled in the third distillation column, and the resulting top fraction is fed to the first distillation column.

Abstract: An object of the present invention is to provide a method for vapor phase catalytic oxidation which is almost free of variations in reaction states in respective reaction tubes of the fixed bed multi-tube heat-exchanger type reactor.

Abstract: The present invention provides a method for efficiently using an aqueous solution of (meth)acrylic acid at a low concentration formed in a production/storage step of (meth)acrylic acid. In the present invention, a (meth)acrylic acid derivative is produced by using as a raw material an aqueous solution of (meth)acrylic acid formed by one or both of: a device which reduces a pressure of a gas comprising (meth)acrylic acid in production of (meth)acrylic acid; and a device which collects (meth)acrylic acid from a gas comprising (meth)acrylic acid.

Abstract: An object of the present invention is to provide a method for producing (meth)acrylic acid or (meth)acrolein by conducting a gas phase catalytic oxidation reaction with an oxygen-containing gas using as a raw material at least one substance to be oxidized selected from propylene, propane, isobutylene and (meth)acrolein using a multi-tubular reactor, which enables a high yield and stable production even when operating constantly with supplying the raw material in the maximum supply amount acceptable by the reactor or an amount close thereto. The invention is a method for producing (meth)acrylic acid or (meth)acrolein wherein, at the time of a start-up of the reaction, for a period of at least 20 hours or more after the supply amount of the raw material to the reactor per unit time reached 30% or more of the acceptable maximum supply amount of the raw material per unit time, the supply amount of the raw material per unit time is kept at 30% or more and less than 80% of the acceptable maximum supply amount.

Abstract: Disclosed is a gas-insulated switchgear device, in which a space for dismantlement and inspection work which facilitates the dismantlement and inspection work of circuit breakers at the time of the occurrence of accidents of the circuit breakers are provided and an installation area for the gas-insulated switchgear device can be reduced. The gas-insulated switchgear device includes a pair of spaced apart main bus lines, three circuit breakers connected between the main bus lines, a common space for dismantlement and inspection work provided between two of the three circuit breakers, and branch bus lines provided above the common dismantlement and inspection work space using the common dismantlement and inspection work space and disposed in such a manner that insulatedly leading-out directions of the branch bus lines cross in order to balance voltage.