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 multi-tubular reaction apparatus, a control system, and a method are provided for controlling temperature change of a heat medium in the reaction apparatus, and quickly adjusting fluctuation in temperature, to thereby properly control a reaction. In particular, the apparatus and system apply to a catalytic gas-phase oxidation reaction such as in producing (meth)acrylic acid or the like. The reaction apparatus includes a multi-tubular reactor having a plurality of reaction tubes in a shell in which a heat medium circulates, and a heat medium cooling apparatus outside the reactor. The reaction apparatus includes a process for primarily cooling the heat medium taken out outside the shell, a process for secondarily cooling a part of the primarily cooled heat medium, and a line for enabling the secondarily cooled heat medium and the primarily cooled heat medium, which is not secondarily cooled, to circulate in the shell.

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: 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: 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 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: 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: 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: In the stopping and starting operations of a distillation column used for producing (meth)acrylic acids according to the present invention, upon stopping the operation of the distillation column, the heating of a reboiler attached thereto is interrupted and then the reboiler is rapidly cooled; and/or upon starting the operation of the distillation column for production of the (meth)acrylic acids, an inner wall surface of the distillation column is heated to a temperature higher than a condensation temperature of the (meth)acrylic acids and the operation of the distillation column is started under the heated condition. According to the present invention, it is possible to early and safely stop the operation of the distillation column while preventing the occurrence of polymerization within the distillation column, and stably perform an operation for distillation of acrylic monomers for a long period of time.

Abstract: A method for producing (meth)acrylic acid or (meth)acrolein, comprising a catalytic gas phase oxidation process for producing (meth)acrylic acid or (meth)acrolein by supplying propylene, propane, or isobutylene and a gas containing molecular oxygen to a reactor which contains a catalyst filled therein, wherein a gas containing molecular oxygen is supplied to the reactor having the catalyst filled therein during shutdown of the catalytic gas phase oxidation process does not lower the reaction activity of the catalyst and the selectivity of target products when re-starting the running after shutdown of the catalytic gas phase oxidation process.

Abstract: In the stopping and starting operations of a distillation column used for producing (meth)acrylic acids according to the present invention, upon stopping the operation of the distillation column, the heating of a reboiler attached thereto is interrupted and then the reboiler is rapidly cooled; and/or upon starting the operation of the distillation column for production of the (meth)acrylic acids, an inner wall surface of the distillation column is heated to a temperature higher than a condensation temperature of the (meth)acrylic acids and the operation of the distillation column is started under the heated condition. According to the present invention, it is possible to early and safely stop the operation of the distillation column while preventing the occurrence of polymerization within the distillation column, and stably perform an operation for distillation of acrylic monomers for a long period of time.

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: An object of the invention is to provide a multi-tubular reaction apparatus and a control system for the same, the multi-tubular reaction apparatus being capable of controlling change in temperature of a heat medium, quickly adjusting fluctuation in temperature, and thereby, properly performing reaction, particularly, the apparatus and system properly applicable to a catalytic gas-phase oxidation reaction such as in producing (meth)acrylic acid or the like.

Abstract: (Meth)acrylic acid is produced using a reactor (1) through a vapor-phase catalytic oxidation reaction of propane or the like in a raw material gas, and the obtained reaction gas is distributed to a heat exchanger (20) and an absorption tower (30). Heat energy is recovered from the reaction gas supplied to the heat exchanger (20), and the reaction gas cooled in the heat exchanger (20) and the reaction gas distributed to the absorption tower (30) are supplied to the absorption tower (30). (Meth) acrylic acid is recovered from the reaction gas in an absorbing liquid, to thereby produce (meth) acrylic acid. The reaction gas is distributed to the heat exchanger (20) and the absorption tower (30) according to a pressure of the raw material gas at an inlet of the reactor (1). The present invention allows heat recovery from the reaction gas and a stable and continuous operation even when the heat exchanger for heat recovery is clogged.

Abstract: An object of the present invention is to provide a pilot test method for suitably setting the reaction conditions for a gas-phase catalytic reaction using a multi-tube reactor, and an apparatus thereof.

Abstract: An object of the invention is to provide a method for producing a reaction gas including (meth)acrylic acid or (meth)acrolein by carrying out a catalytic gas phase oxidation process by supplying propylene, propane, or isobutylene and a gas containing molecular oxygen into a reactor having a catalyst filled therein, wherein such a method is provided, which does not lower the reaction activity of a catalyst and selectivity of target products when re-starting the running after shutdown of the catalytic gas phase oxidation process. The invention relates to a method for producing (meth)acrylic acid or (meth)acrolein, comprising a catalytic gas phase oxidation process for producing (meth)acrylic acid or (meth)acrolein by supplying propylene, propane, or isobutylene and a gas containing molecular oxygen in a reactor having a catalyst filled therein, wherein a gas containing molecular oxygen is supplied in a reactor having the catalyst filled therein during shutdown of the catalytic gas phase oxidation process.