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) and a vertical inner surface (16), a plurality of trays (8) mounted in the column cavity (3) and spaced apart vertically from one another, at least one stub (11) disposed within the column body (2) and extending away from the column body (2), and a closable inspection orifice (9) formed in the stub (11). The characteristic feature of the column of the invention is that in the case of a vertical cross section of the column (1) the surface (15) of the lower line of intersection of the stub (11) directed into the column cavity (3) or a tangent to the surface (15) of the lower line of intersection of the stub (11) at least in sections forms an angle within a range from 210° to 267° with the vertical inner surface (16) of the column body (2) which extends downward from the stub (11).
Abstract:
The invention relates to a process for preparing butadiene from n-butenes having a start-up phase and an operating phase, wherein the process in the operating phase 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, of an oxygen-comprising gas stream a2 and of 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, unreacted n-butenes, water vapor, oxygen, low-boiling hydrocarbons, high-boiling secondary components, possibly carbon oxides and possibly inert gases; C) cooling and compression of the product gas stream b and condensation of at least part of the high-boiling secondary components, giving at least one aqueous condensate stream c1 and a gas stream c2 comprising butadiene, n-butenes, water vapor, oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases; D) introduction of the gas stream c2 into an absorption zone and separation of incondensable and low-boiling gas constituents comprising oxygen, low-boiling hydrocarbons, possibly carbon oxides and possibly inert gases as gas stream d from the gas stream c2 by absorption of the C4-hydrocarbons comprising butadiene and n-butenes in an absorption medium, giving an absorption medium stream loaded with C4-hydrocarbons and the gas stream d, and recirculation, optionally after separating off a purge gas stream p, of the gas stream d as recycle gas stream d2 to the oxidative dehydrogenation zone; and the start-up phase comprises the steps: i) introduction of the oxygen-comprising gas stream and an inert gas stream into the dehydrogenation zone in such a ratio that the oxygen content of the recycle gas stream d2 corresponds to from 30 to 80% of the oxygen content of the recycle gas stream d2 in the operating phase; ii) setting of the recycle gas stream d2 to at least 70% of the volume flow of the recycle gas in the operating phase; iii) optional introduction, at an initial oxygen content of the recycle gas stream d2 of from 30 to 80% of the oxygen content of the recycle gas stream d2 in the operating phase, of a steam stream a3 into the dehydrogenation zone; iv) introduction, at an initial oxygen content of the recycle gas stream d2 of from 30 to 80% of the oxygen content of the recycle gas stream d2 in the operating phase, of an oxygen-comprising gas stream a2′ and a butene-comprising feed gas stream a1′ having a smaller volume flow than in the operating phase in a ratio k=a2′/a1′ and raising of the volume flow of the gas streams a1′ and a2′ until the volume flows of the gas streams a1 and a2 in the operating phase are obtained, with the recycle gas stream d2 being at least 70% and not more than 120% of the volume flow in the operating phase.
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 the process for recovering acrylic acid, comprising the steps a) division of a heated mother acid stream in direction of an absorption column (201) and a dissociation column (205), b) feeding of a heated mother acid substream as runback to the dissociation column (205), c) feeding-in of at least one stripping gas stream to the dissociation column (205), d) feeding-in of a secondary component stream comprising oligomeric acrylic acid from the condensation column (201) to the dissociation column (205), e) dissociation of part of oligomeric acrylic acid in the dissociation column (205) to give monomeric acrylic acid, f) removal of secondary components comprised in the secondary component stream in the dissociation column (205), g) discharge of monomeric acrylic acid as gas mixture with introduced circulating stripping gas stream from the dissociation column (205) and h) feeding-in of the gas mixture to the condensation column (201).
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:
The present invention relates to a column (1) for a thermal treatment of a mixture of compounds having a tendency to polymerization. The column (1) comprises a mass transfer tray (5) comprising a rising tube (8) having an inlet opening (9) below and an outlet opening (10) above the mass transfer tray (5). The rising tube (8) further comprises a lateral opening (11) above the mass transfer tray close to the upper surface of the mass transfer tray (5). Said rising tube (8) is adapted to form a fountain (13) at the outlet opening (10) by atomization of a liquid fraction of the mixture of compounds from the mass transfer tray that enters through the lateral opening into the rising tube (8). The fountain (13) is sprayed to a spot (16) of the column (1) where polymerization is likely to occur. Furthermore, the present invention relates to a thermal separating process that uses such column (1).
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 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 in the column cavity (3) and spaced apart vertically from one another, at least one stub (11) disposed within the column body (2) and extending away from the column body (2), and a closable inspection orifice (9) formed in the stub (11). The characteristic feature of the column of the invention is that a spray device (20) disposed in the column body (2) can spray liquid (22) at least against the surface (15) of the stub (11) directed into the column cavity (3).
Abstract:
The present invention relates to a plant (1) for performance of heterogeneously catalyzed gas phase reactions, comprising a reactor (3), at least one line (11) leading into the reactor (3) for introduction of reactants into the reactor (3), at least one first feed (5) for providing at least one first reactant A, which leads into the line (11), at least one second feed (7) for providing at least one second reactant B, which leads into the line (11), at least one third feed (9) for providing a cycle gas G, which leads into the line (11), a temperature control unit (13) which is disposed in the line (11) upstream of the reactor (3) and is for controlling the temperature of the first reactant A and/or second reactant B and/or cycle gas G prior to entry into the reactor (3) and at least one outlet (15) for products, by-products and/or unreacted reactants from the gas phase reaction. The present invention further relates to a process for performing heterogeneously catalyzed gas phase reactions.
Abstract:
The present invention relates to a heat exchanger (1) comprising a bundle of at least two heat exchanger tubes (3), a heat exchanger housing (5) surrounding the bundle of heat exchanger tubes (3), wherein a liquid heat-transfer medium (7) is passed around the bundle of heat exchanger tubes (3) in the heat exchanger housing (5), a heat exchanger cap (9) sealing the top of the heat exchanger housing (5), a heat exchanger bottom (11) sealing the bottom of the heat exchanger housing (5), a feed point (13) for the heat-transfer medium (7), an outlet (15) for the heat-transfer medium (7), an emergency relief port (17) disposed in proximity to the heat exchanger cap (9). The heat exchanger (1) comprises a safety device (19) disposed in proximity to the heat exchanger bottom (11).The present invention further relates to a reactor arrangement (101).