Abstract: A process for producing an eggshell catalyst, comprising the coating of the outer surface of a geometric shaped support body with a catalytically active multielement oxide or a powder P, wherein the powder P, after being coated, is converted by thermal treatment to a catalytically active multielement oxide, and one or more liquid binders, wherein the coating is conducted in a horizontal mixer and the Froude number during the coating in the horizontal mixer is from 0.0160 to 0.1200.

Abstract: The present invention relates to a method for transporting a liquid F by means of a pump P, wherein the liquid F comprises at least 10% by weight of a (meth)acrylic monomer, the pump P has a pump space (3), the pump space (3) comprises at least one transport element (4) for transporting the liquid F, the transport element (4) is connected to a drive shaft (6) in such a way that the drive shaft (6) can transmit a torque to the transport element (4), the mounting of the drive shaft is effected by means of at least two sliding bearings (5) in the pump space (3) and the sliding bearings (5) are composed of tungsten carbide.

Abstract: The present invention relates to a method of redissociating Michael adducts of acrylic acid present in a liquid F in a redissociation apparatus comprising at least one separating column K, an evaporator V and a pump P, wherein, in the event of an unwanted rise in the viscosity of the residue R in the bottom space of the separating column K, the feed of the liquid F into the redissociation apparatus is stopped, the residue R in the bottom space of the separating column K is diluted and cooled with a solvent 1, and the bottom space of the separating column K is emptied.

Abstract: The present invention relates to a process for recovering acrylic acid which is obtained by catalytic gas phase oxidation of propene, wherein, in an absorption stage (K2), the acrylic acid is absorbed from the reaction mixture (1) from the gas phase oxidation with a first solvent (3) and is drawn off for distillative purification, and a gas mixture from the absorption stage (K2) is passed onward to a condensation stage, wherein, in the condensation stage, the gas mixture is condensed, and a condensed phase of the gas mixture is drawn off as acid water (4) and is subjected to a phase separation operation in a phase separation vessel (B1), comprising the steps of a) feeding the aqueous phase (4*) of the acid water (4) drawn off from the condensation stage that has been obtained in the phase separation vessel (B1) to an extraction stage (K7) in which acrylic acid present in the acid water (4) is extracted with a second solvent (5), b) feeding the acrylic acid-comprising extract (6) to a stripping column (K8) in

Abstract: Process for inhibiting the undesired free-radical polymerization of acrylic acid present in a liquid phase P, wherein the acrylic acid content of P is at least 10% by weight, the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal based on the weight of the acrylic acid present in P and the liquid phase P is admixed with furfural in an amount that results in a furfural content in the range from 25 to 1000 ppmw based on the weight of the acrylic acid present in P. Liquid phase P, wherein the acrylic acid content of P is at least 10% by weight and the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal and in the range from 25 to 1000 ppmw of furfural in each case based on the weight of the acrylic acid present in P.

Abstract: Process for inhibiting the undesired free-radical polymerization of acrylic acid present in a liquid phase P, wherein the acrylic acid content of P is at least 10% by weight, the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal based on the weight of the acrylic acid present in P and the liquid phase P is admixed with furfural in an amount that results in a furfural content in the range from 25 to 1000 ppmw based on the weight of the acrylic acid present in P. Liquid phase P, wherein the acrylic acid content of P is at least 10% by weight and the liquid phase P comprises in the range from 25 to 1000 ppmw of glyoxal and in the range from 25 to 1000 ppmw of furfural in each case based on the weight of the acrylic acid present in P.

Abstract: Multimetal oxide composition comprising Mo, Bi, Fe, Cu and one or more than one of the elements Co and Ni and use thereof.

Abstract: The present invention relates to a column (1) for thermal treatment of fluid mixtures, having a cylindrical, vertically aligned column body (2) which forms a column cavity (3), having a sequence of vertically spaced-apart dual-flow mass transfer trays (8) which are mounted in the column cavity (3) and which have orifices for passage of liquid and gas in countercurrent, and having at least one gas entry orifice (5) disposed below the lowermost of the sequence of dual-flow mass transfer trays (8). It is a characteristic feature of the column of the invention that a gas distribution tray (9) which is disposed between the lowermost of the sequence of dual-flow mass transfer trays (8) and the gas entry orifice (5) has orifices (32) for vertical passage of gas which can be introduced into the column cavity (3) via the gas entry orifice (5), the orifices (32) being formed so as to bring about equal gas distribution over the column cross section.

Abstract: The present invention relates to a chimney tray (3) for a column (1) for thermal treatment of fluid mixtures, comprising a collecting tray (4) and at least two chimneys (5-1, 5-2) spaced apart horizontally in the collecting tray (4), where each chimney (5-1, 5-2) forms a vertically aligned chimney body (6-1, 6-2) which forms a passage orifice (7-1, 7-2) through the collecting tray (4), and has a cover unit (8-1, 8-2) arranged spaced apart from the chimney body (6-1, 6-2), and where the cover unit (8-1, 8-2) covers the respective passage orifices (7-1, 7-2) in the vertical direction.

Abstract: Process for preparing butadiene from n-butenes, which has a start-up phase and an operating phase and the operating phase of the process comprises the steps: A) provision of a feed gas stream a1 comprising n-butenes; B) introduction of the feed gas stream a1 comprising n-butenes, an oxygen-comprising gas stream a2 and an oxygen-comprising recycle gas stream d2 into at least one oxidative dehydrogenation zone and oxidative dehydrogenation of n-butenes to butadiene, giving a product gas stream b comprising butadiene; C) cooling and compression of the product gas stream b, giving at least one aqueous condensate stream c1 and a gas stream c2 comprising butadiene; D) introduction of the gas stream c2 into an absorption zone and separation of incondensable and low-boiling gas constituents as gas stream d from the gas stream c2 by absorption of the C4 hydrocarbons in an absorption medium, giving an absorption medium stream loaded with C4 hydrocarbons and the gas stream d, and recirculation of the gas stream d as re

Abstract: The present invention relates to a column (1) for thermal treatment of fluid mixtures, having a cylindrical, vertical column body (2) which forms a column cavity (3), a plurality of trays (8) mounted with vertical spacing in the column cavity (3), and a support construction (9) which supports at least one of the trays (8) in vertical direction. It is a characteristic feature of the inventive column (1) that the support construction (9) has a plurality of orifices (12) which allow horizontal mass transfer through the support construction (9). The invention further relates to a tray device for such a column and to a thermal separation process between at least one gas ascending within such a column (1) and at least one liquid descending within the column (1).

Abstract: Multimetal oxide composition comprising Mo, Bi, Fe, Cu and one or more than one of the elements Co and Ni and use thereof.

Abstract: A plant (1) for recovering acrylic acid, which includes: a absorption column (201); a dissociation column (205); a first line (101) connected to the dissociation column (205); a second line (102) connecting the absorption column (201) and the dissociation column (205); a third line (103) feeding a substream of the mother acid obtained in the crystallization into the dissociation column (205); a fourth line (104) connecting the crystallization apparatus and the absorption column (201); and a fifth line (105) connecting the dissociation column (205) and the absorption column (201).

Abstract: A reactor system (1) having a reactor 3, at least one cooler (5) connected to the reactor (3), at least one pump (7) for circulating at least some of a liquid heat-transfer medium (9), wherein the pump (7) is connected to the reactor (3) and/or the at least one cooler (5), and a container (11) for collecting the liquid heat-transfer medium (9) is provided. The container (11) is connected to the reactor (3) and/or the at least one cooler (5) and is disposed substantially below the reactor (3) and/or the at least one cooler (5). Also provided are exothermic reactions which are conducted in the reactor system.

Abstract: The invention relates to a crossflow tray for a mass transfer column (27) in which a gas is conducted in countercurrent to a liquid, the crossflow tray (1) having passage orifices (3) for the gas and at least two downcomers (5), the downcomers (5) projecting beyond the top surface of the crossflow tray (1) and a collecting cup (13) being disposed beneath each downcomer (5). The downcomer (5) projects into the collecting cup (13), the minimum horizontal cross-sectional area of the collecting cup (13) is 1.2 to 4 times greater than the horizontal cross-sectional area of the downcomer (5) at the outlet, and the collecting cup (13) has a circumferential wall (15) having an overflow (19). The invention further relates to a mass transfer column comprising the crossflow trays and to a use of the mass transfer column.

Abstract: The present invention relates to an apparatus (1) for separation of a target product from a liquid phase P comprising the target product, comprising at least one primary space (3) for a heat transfer medium W, at least one first feed unit (5a) and one first removal unit (5b) for the heat transfer medium W, at least one secondary space (7) for the liquid phase P, at least one second feed unit (9) for the liquid phase P, at least one crystallization surface (13) which divides the primary space (3) and the secondary space (7), at least one second removal unit (15) for the target product and at least one application unit (11) for a liquid phase P0 essentially directly to the crystallization surface (13) or the surfaces of lines that conduct the heat transfer medium W. The present invention further relates to a process for removing a target product from a liquid phase P comprising the target product.

Abstract: A system (1) and method for operating a liquid gas evaporator (3), comprising an evaporator (3), a trough (5) carrying the evaporator (3), a housing (7) which surrounds the evaporator (3) on three sides, at least one detector (9) for sensing liquid gas arranged in the trough (5), a line (11) for the distribution of vapor D on the fourth, non-housed side of the evaporator (3) arranged at the margin of the trough (5) which is not closed off by the housing (7), a feed (13), connected to the line (11), and a regulating valve (15) provided on the feed (13) and connected to the detector (9) and at least one shut-off valve (17).

Abstract: The present invention relates to a process for treating secondary components obtained in acrolein and/or (meth)acrylic acid production, comprising the steps of: a) contacting at least one wastewater stream (201) comprising at least a portion of the water of reaction removed in a first stage of a saturation column (101) with at least one process offgas stream (203), b) introducing energy by means of a first heat transferer (103) provided in a first saturation circuit (301) into the first stage of the saturation column (101), c) partly vaporizing the wastewater stream (201) into the process offgas stream (203) and passing the combined gas stream (205) into a second stage of the saturation column (101), d) drawing off a concentrated wastewater stream (207) from the bottom (1011) of the first stage of the saturation column (101) and feeding it to the top (1023) of the second stage of the saturation column (101), e) introducing energy by means of a second heat transferer (105) provided in a second circuit (303) i

Abstract: Process for producing a multimetal oxide catalyst comprising molybdenum, chromium and at least one further metal by mixing of a pulverulent multimetal oxide comprising molybdenum and at least one further metal but no chromium with pulverulent chromium(III) oxide and thermal treatment of the resulting pulverulent mixture in the presence of oxygen at a temperature in the range from 350° C. to 650° C.

Abstract: The present disclosure includes a column (1) having a cylindrical, vertical column body (2) forming a column cavity (3), and a mass transfer tray (4) disposed in the column cavity (3) and forming a collecting area (5). The column (1) is characterized by a circulation device (9) having at least one drain orifice (10) formed in the column body (2) above the collecting area (5), a circulation line (11) in fluid connection with the drain orifice (10) and at least one recycling orifice (14; 14-1 to 14-3) which is in fluid connection with the circulation line (11) and is formed in the column body (2) above the collecting area (5). Also disclosed herein is a thermal separating process in which a gas ascends within a column (1) of the present disclosure, and a liquid descends within the column (1), said gas and/or liquid containing (meth)acrylic monomers.