摘要:
The subject of the present invention is a process for preparing acrolein by dehydration of glycerol in the presence of a catalyst system comprising oxygen, phosphorus and at least one metal chosen from vanadium, boron or aluminium. The process is preferably carried out in the gas phase in the presence of oxygen starting from aqueous solutions of glycerol. The process according to the invention makes it possible to obtain high acrolein selectivities.
摘要:
The invention relates to a multi-layered catalyst bed for producing phthalic anhydride by gas phase oxidation of o-xylol and/or naphtaline, which contains at least three differently composed catalyst layers, respectively an active mass, which are characterised as a first, second and/or third catalyst layer which leads from the gas inlet side to the gas outlet side. Said catalyst layers comprise an active mass containing TiO2 having a NA content of less that 0.3 wt. %, and the active mass content decreases from the first catalyst layer, which is placed in the direction of the gas inlet side, to the third catalyst layer, which is placed in the direction of the gas outlet side, under the proviso that (a) the first catalyst layer has an active mass content of between 7 and 12 wt. %, (b) the second catalyst layer has an active mass content in the region of between 6 and 11 wt %. The active mass content of the second catalyst layer is smaller or equal to the active mass content of the first catalyst layer, and (c) the third catalyst layer has an active mass content in the region of between 5 and 10 wt. %. The active mass content of the third catalyst layer is smaller or equal to the active mass content of the second catalyst layer. The invention also relates to a preferred method for producing said type of multi-layered catalyst bed, and to the preferred use of the titanium dioxide which is used according to the invention.
摘要:
Embodiments of the present invention include improved shaped catalyst structures containing catalytic material comprised of mixed oxides of vanadium and phosphorus and using such shaped catalyst structures for the production of maleic anhydride.
摘要:
The invention relates to a catalyst for catalytic gas phase oxidation of aromatic hydrocarbons to form aldehydes, carboxylic acids and/or carboxylic acid hydrides, in particular phthalic acid anhydride. The active mass comprises vanadium oxide, preferably vanadium pentoxide, titanium dioxide, preferably in the anatas-modification, and at least one silver mixing element oxide with defined elements, preferably vanadium and/or molybdenum and/or tungsten and/or niobium and/or antimony, and/or a vanadium mixing element oxide with defined elements, preferably bismuth and/or molybdenum and/or tungsten and/or antimony and/or niobium. When producing the catalyst, in particular during the production of a catalyst suspension or a powder mixture necessary for coating a carrier, at least one silver and/or vanadium mixing element oxide and/or at least one precursor compound, in particular at least one multi-core precursor compound, of at least one silver and/or vanadium mixing element oxide is used as a raw material source.
摘要:
The present invention relates to a process for preparing vanadyl pyrophosphate catalyst with improved structural characteristics for the selective oxidation of butane to maleic anhydride. The process comprises the steps of preparing VOHPO4 ⋅ 0,5 H20 stirring it in a mixture of DMF and water, recovering and calcining it. The catalyst obtained exhibits selective exposure of the (100) plane.
摘要:
A method for production of a catalyst for gas phase oxidations is disclosed, whereby a suspension of Ti02 and V205 particles is applied to a fluidised inert support, wherein at least 90 vol. % of the V205 particles have a diameter of 20 μm or less and at least 95 vol. % of the V205 particles have a diameter of 30 μm or less. The defined particle size distribution of the V205 permits a high coating efficiency.
摘要:
The present invention provides a process for producing a vanadium/phosphorus oxide catalyst by (i) preparing a catalyst precursor powder containing vanadium, phosphorus and an optional promoter element; (ii) converting the catalyst precursor powder into an activated catalyst by heat treatment; (iii) and compressing the activated catalyst into a desired shape to form the vanadium/phosphorus oxide catalyst. The vanadium/phosphorus oxide catalyst may be used in the production of maleic anhydride by the catalytic oxidation of hydrocarbon feed streams.
摘要:
Disclosed is a method for producing a catalyst containing vanadium, phosphorus, and oxygen, which is used for oxidizing the gas phase of a hydrocarbon having at least four carbon atoms to maleic anhydride. According to the inventive method, a corresponding catalyst precursor which contains vanadium, phosphorus, and oxygen and is provided with particles having an average diameter of at least 2 mm is converted into a catalytically active form by means of calcination, and a flow of the catalyst precursor is transported on a conveyor belt across at least one calcination area over a distance ln at an essentially steady speed in order to be calcinated. The variation over time of the gas temperature in relation to the set point value amounts to ≤ 5 °C at each position in the area of the flow of the catalyst precursor, which lies within the second half ln/2 of the calcination area, while the local difference in the gas temperature between any positions in the area of the flow of the catalyst precursor, which is located within the second half ln/2 of the calcination area, amounts to ≤ 5 °C.
摘要:
Described herein is a process in which acetic acid is produced by ethane oxidation. One byproduct of the ethane oxidation is ethylene. High ethylene content in the recycle gas stream will lead to poor efficiencies and higher losses to the COx byproduct in the acetic acid reactor. In fact, ethylene in the recycle feed competes with the ethane for the limited amount of oxygen feed, resulting in higher inefficiencies to carbon oxides than straight ethane oxidation. Ethylene is removed in this process by a further oxidation reaction at a temperature low enough such that ethane is not reactive, but the ethylene is converted to acetic acid. Either the ethane oxidation reactor effluent or a portion or all of the recycle stream to the ethane oxidation reactor, or any combination of the same, can be processed in this manner to reduce the ethylene content of those streams.