Abstract: A chimney tray for a column for the thermal treatment of a liquid, comprising an upper tray and a lower tray which are spaced apart from one another, arranged substantially horizontally in the column, comprising chimneys, and also comprising drawing of the liquid via a drainage spout arranged at the edge of the chimney tray, wherein the upper tray and the lower tray have a minimum separation from one another of from 10 to 500 mm and, between the upper tray and the lower tray, a gas having a thermal conductivity of less than 0.5 watt/m/K has been incorporated.

Abstract: A continuously operated heterogeneously catalyzed gas-phase partial oxidation of at least one organic compound in an oxidation reactor is operated safely by a process in which an explosion diagram for the feed gas mixture is deposited as the basis of a cut-out mechanism in a computer.

Abstract: A tray column is proposed which comprises column trays, two or more supports which are arranged on the underside of the column trays and support them and a bearing ring for the column trays on the inner wall of the tray column, wherein three-way joints of inner column wall, bearing ring and support are prevented by cutouts in the bearing ring.

Abstract: A method of charging catalyst tubes of a bundle of catalyst tubes in a structured fashion, in which uniformly predispensed portions of formulations of shaped catalyst bodies are used for producing a section of charge.

Abstract: A process for the catalytic gas-phase oxidation of propene to acrylic acid, in which the reaction gas starting mixture is oxidized, with a high propene loading, in a first reaction stage, over a first fixed-bed catalyst which is housed in two successive reaction zones A, B, the reaction zone B being kept at a higher temperature than the reaction zone A, and the acrolein-containing product gas mixture of the first reaction stage is then oxidized in a second reaction stage, with a high acrolein loading, over a second fixed-bed catalyst which is housed in two successive reaction zones C, D, the reaction zone D being kept at a higher temperature than the reaction zone C.

Abstract: The present invention relates to a process for preparing acrylic acid by two-stage heterogeneously catalyzed partial gas phase oxidation of propylene, in which the propylene source used is a preceding propane dehydrogenation and in which the first oxidation stage is operated with restricted propylene conversion, and unconverted propane and propylene present in the product gas mixture of the second partial oxidation stage are recycled substantially into the preceding propane dehydrogenation.

Abstract: Organic compounds are prepared by heterogeneously catalyzed partial gas-phase oxidation of precursor compounds by a process in which a portion of the reaction gas starting mixture is brought from a low initial pressure to a higher final pressure by means of a radial compressor.

Abstract: In a process for rectificatively separating (meth)acrylic monomer-containing fluids, a rectification column is employed which has at least one sieve tray without runoff segment in which the passages are arranged regularly.

Abstract: In a process for preparing acrylic acid, an acrylic acid-containing product gas mixture obtained by catalytic gas phase partial oxidation of a C3 precursor of acrylic acid, after direct cooling with a quench liquid, is fractionally condensed in a separating column provided with internals, rising into itself with sidestream takeoff of crude acrylic acid, and the acrylic acid oligomers which form are dissociated and the resulting dissociation gas is subjected to a countercurrent rectification before it is recycled.

Abstract: A process for the fractional condensation of a hot gas mixture which as well as acrylic acid contains at least one further condensable component in a column in the presence of at least one stabilizer comprises metering in at least a portion of the at least one stabilizer as a melt.

Abstract: A process measures the pressure of a gas phase containing (meth)acrylic acid, the esters and/or nitrites thereof of a rectification and/or absorption column via open drillholes in the column wall and lines from the drillholes to the transducers by purging the lines with an oxygen-containing gas in the direction toward the open drillhole.

Abstract: In process for cleaning tray columns which are used for the purposes of rectifiying liquids comprising (meth)acrylic compounds, a basic liquid is conveyed downward through the tray column and a gas is passed through the column in countercurrent to the basic liquid at an average gas phase differential pressure over all trays of at least 0.5 mbar/tray.

Abstract: The invention described herein relates to a process for removing solids from tubes of a tube bundle heat exchanger, wherein a drill driven by a drilling machine is inserted into a tube of the tube bundle heat exchanger and clears out solids present in the tube. In a first variant of the process according to the invention, the drill is a spiral drill and has, cut out in the outer casing of the drill, a spiral conveyor groove in which the solids particles loosened and isolated by the drill tip on insertion of the drill into the tube can be transported out of the tube. More preferably, the drill is a hollow drill 10 which is provided with a substantially circular drill tip 11 and has a central recess running along the rotational axis in the longitudinal direction of the drill and opening into the drill tip 11 at the free end of the drill. At the drill tip 11 are provided toothlike projections 12.

Abstract: A thermal separating process for removing a stream containing enriched (meth)acrylic monomers from a mixture containing (meth)acrylic monomers, in which the liquid phases retained in the separating space at high temperature and high (meth)acrylic monomer content are minimized.

Abstract: A process for preparing hydroformylation products of propylene and for preparing acrylic acid and/or acrolein comprises a) feeding a propylene-containing feed in which from 2 to 40% by weight of propane is present and also carbon monoxide and hydrogen into a reaction zone and reacting this mixture in the presence of a hydroformylation catalyst to form hydroformylation products of propane, b) separating a stream consisting essentially of unreacted propylene and propane from the output from the reaction zone, and c) subjecting the stream consisting essentially of propylene and propane to a catalytic gas-phase oxidation in the presence of molecular oxygen to form acrylic acid and/or acrolein.

Abstract: Process for operating a continuous heterogeneously catalyzed gas phase partial oxidation of at least one organic compound using compressed air as the oxygen source which is filtered before its compression.

Abstract: The invention relates to a riser base (1), which is provided for a column used for thermally treating a liquid and from which liquid is completely drained via a drainage tube (6) located at the edge of the riser base (1). The riser base (1) comprises one or more drainage channels (5) that slope(s) toward the drainage tube (6), and the riser base (1) slopes toward the drainage channel(s) (5).

Abstract: A clamp for detachable connection of a column tray to a support ring in a column. The clamp includes a bolt lower clamp part connected to the bolt. The lower clamp part has at least one orifice through which a liquid present in the column can flow away.

Abstract: An apparatus for separating crystals from their suspension in contaminated crystal melt with purification, in which a hydraulic wash column has distributor aids in a distributor space.

Abstract: A thermal separating process for removing a stream containing enriched (meth)acrylic monomers from a mixture containing (meth)acrylic monomers, in which the liquid phases retained in the separating space at high temperature and high (meth)acrylic monomer content are minimized.