Abstract: A plate type catalytic reactor in which components of a starting material gas react comprises a plurality of pairs of heat transfer plates, each pair being formed of two sheets of corrugated plates joined to each other and each pair having a plurality of interior heat transfer medium flow passages, that are arranged so that projected surface parts and recessed surface parts of the corrugated plates of adjacent heat transfer plates are opposed to each other and so that the plurality of pairs of corrugated plates placed in contiguous non-contacting relationship define a plurality of catalyst bed regions in which catalyst material is placed, each having an inlet for the flow of starting gas material and an outlet for the egress of reaction product, wherein the direction of flow of the heat transfer medium through the passages is perpendicular to the direction of flow of starting material gas through the plurality of catalyst regions.

Abstract: The present invention provides a process for catalytic vapor phase oxidation which prevents runaway reaction or early deterioration of a catalyst, in the production of (meth)acrylic acid or the like from propylene or isobutylene by the catalytic vapor phase oxidation process using a multi-tubular reactor, which can lead to the production thereof constantly in high yield for a long period of time.

Abstract: In the process for producing (meth)acrolein or (meth)acrylic acid, which comprises feeding a raw material of the (meth)acrolein or (meth)acrylic acid, and a molecular oxygen-containing gas mixed with a diluting gas and compressed by a compressor, to an oxidation reactor to conduct a catalytic gas-phase oxidation reaction therebetween; feeding the obtained reaction gas to an absorption column to contact with water; recovering an aqueous solution of the (meth)acrolein or (meth)acrylic acid from a bottom of the absorption column and an exhaust gas from a top of the absorption column; and recycling a part or whole of the thus recovered exhaust gas to use as the diluting gas, the temperature of the mixed gas at a suction inlet of the compressor is controlled to a temperature higher than a dew point thereof. According to the process of the present invention, the compressor is prevented from suffering from clogging or damage thereto.

Abstract: The present invention provides a process for recovering liquid chemical products, in which the residual liquid chemical products remaining in respective handling devices in a chemical production facility can be efficiently and safely recovered therefrom without leakage thereof out of the system. In the process for recovering liquid chemical products in a chemical production facility according to the present invention, the chemical products are withdrawn from the handling devices through bottom discharge pipes (14), (15), (16) and (17) thereof, directly collected by the gravity thereof into a common inclined collection pipe (13) located at a position lower than the bottom discharge pipes and connected to the bottom discharge pipes, and then delivered by the gravity thereof through the inclined collection pipe (13) to a recovery tank (1) located at a position lower than the inclined collection pipe and connected to a lower end of the inclined collection pipe.

Abstract: A plate type catalytic reactor capable of improving reaction performance and extending the service life of the catalyst by controlling efficiently a temperature profile in a catalyst layer, is presented. A plate type catalytic reactor characterized in that a plurality of pairs of heat transfer plates, each formed of two sheets of corrugated plates joined to each other and each having a plurality of heat transfer medium flow passages, are arranged so that projected surface parts and recessed surface parts of the corrugated plates of adjacent heat transfer plates are opposed to each other to form a catalyst layer, wherein a circular or elliptic arc shape formed in the corrugated palates may be changed to increase the thickness of the catalyst layer from the inlet toward the outlet for a starting material gas fed to the catalyst layer.

Abstract: The present invention provides a process for recovering liquid chemical products, in which the residual liquid chemical products remaining in respective handling devices in a chemical production facility can be efficiently and safely recovered therefrom without leakage thereof out of the system. In the process for recovering liquid chemical products in a chemical production facility according to the present invention, the chemical products are withdrawn from the handling devices through bottom discharge pipes (14), (15), (16) and (17) thereof, directly collected by the gravity thereof into a common inclined collection pipe (13) located at a position lower than the bottom discharge pipes and connected to the bottom discharge pipes, and then delivered by the gravity thereof through the inclined collection pipe (13) to a recovery tank (1) located at a position lower than the inclined collection pipe and connected to a lower end of the inclined collection pipe.

Abstract: The present invention provides a process for catalytic vapor phase oxidation which prevents runaway reaction or early deterioration of a catalyst, in the production of (meth)acrylic acid or the like from propylene or isobutylene by the catalytic vapor phase oxidation process using a multi-tubular reactor, which can lead to the production thereof constantly in high yield for a long period of time.

Abstract: In the process for producing (meth)acrolein or (meth)acrylic acid, which comprises feeding a raw material of the (meth)acrolein or (meth)acrylic acid, and a molecular oxygen-containing gas mixed with a diluting gas and compressed by a compressor, to an oxidation reactor to conduct a catalytic gas-phase oxidation reaction therebetween; feeding the obtained reaction gas to an absorption column to contact with water; recovering an aqueous solution of the (meth)acrolein or (meth)acrylic acid from a bottom of the absorption column and an exhaust gas from a top of the absorption column; and recycling a part or whole of the thus recovered exhaust gas to use as the diluting gas, the temperature of the mixed gas at a suction inlet of the compressor is controlled to a temperature higher than a dew point thereof. According to the process of the present invention, the compressor is prevented from suffering from clogging or damage thereto.

Abstract: A method for purifying acrylic acid, which comprises carrying out dehydration distillation of an aqueous solution of acrylic acid by means of a dehydration column, wherein a distillation column having a theoretical plate number of at least 3 plates is used as the dehydration column, and the operational temperature of a site corresponding to the second theoretical plate is adjusted to be from 50 to 78° C.

Abstract: In a process for producing acrylic acid, wherein propylene and/or acrolein is catalytically oxidized with molecular oxygen in a vapor phase and the gas resulting from the oxidation is cooled and/or absorbed in water to form a crude aqueous acrylic acid, followed by azeotropic distillation to remove the water with an entrainer of a boiling point of no higher than 130.degree. C. on the crude aqueous acrylic acid which may have, upon necessity, undergone removal of aldehydes contained therein to produce acrylic acid purified in that the crude aqueous acrylic acid is substantially dehydrated, the improvement which comprises conducting the azeotropic distillation under such conditions that concentrations of the entrainer and water in the bottom product of the azeotropic distillation are from 5% to 30% by weight and no higher than 0.

Abstract: Crystallization method and crystallization apparatus each use vertical plates for crystallization thereon. Both surfaces of the plate are used for different two liquids to flow down as films. Specifically, on one vertical surface, a feed liquid mixture containing crystallizable components therein flows down as a film, and on an opposite vertical surface, a cooling medium flows down as a film. Accordingly, the crystallizable component contained in the feed liquid mixture is cooled and crystallized to form crystal layers on the one vertical surface of the plate. The formed crystal layers are melted by a heating medium which flows down on the opposite vertical surface, and are collected as a melt. A pair of the plates may be used to form a unit to purify the liquid mixture on a large scale. A number of the units may be used to form a block which is suitable for a larger-scale crystallization processing.

Abstract: In a non-agitational, countercurrent flow type of liquid-liquid contacting tower, splitter plates with plural slits and/or holes through which light and heavy liquids flow, and baffles having the appropriate shapes and areas in order to cover the liquid flowing upward or downward, are alternately mounted horizontally inside the tower shell in vertical direction. The ratios of the opening area to the total cross-sectional area in the splitter plate are 10% to 40%, and the opening area of a baffles is larger than the aperture area of a splitter plate. The advantages of this invention are as follows: Because of the high contacting efficiency, a relatively smaller contactor has an equivalent performance with that of a larger contactor; there exists no risk of plugging due to scum accumulation, and maintenance is easy.

Abstract: There is provided a process for producing an acrylic or methacrylic ester, comprising the steps of:(a) reacting acrylic or methacrylic acid with an alcohol having 4 or more-carbon atoms in the presence of an acid catalyst to synthesize the corresponding ester;(b) washing the reaction liquid obtained in step (a) with water, followed by separation into the reaction liquid and an aqueous solution containing the acid catalyst; and(c) recycling the aqueous solution obtained in step (b) to step (a).

Abstract: A shell-and-tube apparatus, more specifically, a shell-and-tube reactor, which includes a vessel, at least one intermediate tube plate sectioning the interior of the vessel into at least two compartments having different temperatures, a number of heat transferring tubes penetrating the intermediate tube plate or plates, and a fluid passing through the tubes which is heated or cooled by a heat transfer medium surrounding the tubes. At least one insulation plate or plates are provided on one or both sides of the intermediate tube plate so that the space between the intermediate tube plate or plates and, if two or more insulation plates are used, the space or spaces between the insulation plates may be utilized as a stagnation zone for the heat transfer medium, so as to make the temperature gradient through the intermediate tube plate or plates gentle and relax the thermal stress occurring in the body wall.

Abstract: A 1,2-unsaturated carboxylic acid or its ester such as acrylic or methacrylic acid or its alkyl ester is purified to remove aldehyde impurities contained therein by treating the acid or its ester with a mercapto containing compound in the presence of an acid catalyst.