Abstract:
Disclosed is a method for long-term operation of a heterogeneously catalyzed partial gas phase oxidation of propene to obtain acrolein, in which the propene contained in the fed reaction gas mixture is partially oxidized when said gas mixture penetrates the fixed catalyst bed that is accommodated in two spatially successive temperature zones A, B, and in order to prevent the quality of the fixed catalyst bed from deteriorating during long-term operation, the temperature in at least one of the two temperature zones is raised in such a way that the difference TB- TA becomes greater and greater, where TB is the temperature in temperature zone B and TA is the temperature in temperature zone A.
Abstract:
The invention relates to a method for manufacturing geometric catalyst molded bodies K, the active mass of which is a multi-element oxide, which contains the element Mo, the elements Bi and/or V, and one or more of the elements Co, Ni, Fe, Cu, and alkali metals, wherein a fine-particle mixture is produced using sources of the various elements, said fine-particle mixture is coarsened into a powder by compression agglomeration, molded bodies V are formed from the coarsened powder by compression agglomeration, said molded bodies are separated into undamaged molded bodies V+ and damaged molded bodies V-, the undamaged molded bodies V+ are transformed into the catalyst molded bodies K by thermal treatment, and the damaged molded bodies V- are ground and fed back into the production of the fine-particle mixture.
Abstract:
Preparing catalytically active composition including a mixture made of a multi element oxide comprising molybdenum and vanadium and at least one oxide of molybdenum, comprises e.g. obtaining a spray-dried powder by spray-drying the aqueous solution comprising multi element oxide or an aqueous suspension, (iii) uniformly mixing the spray-dried powder, at least one powdery oxide of molybdenum and optionally at least one forming agent to obtain a mixture and forming geometrical precursor bodies, and (iv) thermally treating the geometrical precursor bodies. Preparing a catalytically active composition including a mixture made of a multi element oxide comprising molybdenum and vanadium and at least one oxide of molybdenum, comprises (i) preparing an aqueous solution by sources of the elemental constituents of the multi element oxide or an aqueous suspension with the condition that each of the sources passes through the state of an aqueous solution during producing the aqueous suspension, (ii) obtaining a spray-dried powder by spray-drying the aqueous solution or the aqueous suspension, (iii) uniformly mixing the spray-dried powder, at least one powdery oxide of molybdenum and optionally at least one forming agent to obtain a mixture and forming geometrical precursor bodies, and (iv) thermally treating the geometrical precursor bodies. Independent claims are also included for: (1) a catalyst comprising a geometric shaped support body, the catalytically active composition obtained by the above mentioned method, which is applied on the outer surface of the geometric shaped support body, and optionally a binding agent; and (2) heterogeneously catalyzed partial gas phase oxidation of methacrolein to methacrylic acid, using at least one catalyst obtained by the above mentioned method.
Abstract:
Catalyst comprises a support molded body with an active material, which is applied on the support molded body. The active material covering (q) is not > 0.3mg/mm 2>. The active material covering (q) is represented by an equation comprising (q) is equal to (Q/((100-Q)S m)) and Q is the active material of the catalyst in wt.%, and S m is the specific geometric surface area of the support molded body in mm 2>/mg. Independent claims are also included for: (1) preparing the catalyst, comprising coating the support molded body with the active material by mixing many support molded bodies, powdery active material and a liquid binder in a container without saturating the powdered active mass with the liquid binder, where the duration of the coating process is less than 30 minutes; and (2) producing alpha , beta -unsaturated carboxylic acid comprising carrying out gas phase oxidation of alpha , beta -unsaturated aldehyde with molecular oxygen over a fixed catalyst filling, where the fixed catalyst filling comprises a filling of the catalyst.
Abstract:
Mo-, Bi- and Fe-comprising multimetal oxide compositions of the general stoichiometry I, Mo12BiaCobFecKdSieOx (I), where a = 0.5 to 1, b = 7 to 8.5, c = 1.5 to 3.0, d = Oto0.15, e = 0 to 2.5 and x = the stoichiometric coefficient of 02- which guarantees the electric neutrality of the multimetal oxide, and 12-b-l.5?c=A and 0.5 ? A ? 1.5, 0.2 ? a/A ? 1.3, and 2.5 ? b/c ? 9, and the use thereof.
Abstract:
The invention relates to an oxidation catalyst comprising at least one inorganic, oxidic or ceramic, shaped support body having a BET surface area of less than 0.5 m2/g, based on the support, which is at least partly coated with a catalytically active multielement oxide, the catalyst being precious metal-free and the shaped support body having the form of a saddle whose saddle surface is curved oppositely in the two principal directions, to a process for producing it, to its use in various catalytic gas phase oxidations, and to corresponding processes for catalytic gas phase oxidation.
Abstract:
Die Erfindung betrifft einen Oxidationskatalysator, umfassend mindestens einen anorganischen oxidischen oder keramischen Trägerformkörper mit einer BET-Oberfläche von weniger als 0,5 m2/g, bezogen auf den Träger, der mindestens teilweise beschichtet ist mit einem katalytisch aktiven Multielementoxid, wobei der Katalysator edelmetallfrei ist und der Trägerformkörper die Form eines Sattels hat, dessen Sattelfläche in den beiden Hauptrichtungen entgegengesetzt gekrümmt ist, ein Verfahren zu seiner Herstellung, seine Verwendung in unterschiedlichen katalytischen Gasphasenoxidationen und entsprechende Verfahren zur katalytischen Gasphasenoxidation.
Abstract:
Mo, Bi und Fe enthaltende Multimetalloxidmassen der allgemeinen Stöchiometrie I, Mo12 Bia Cob Fec Kd Sie Ox (I),mit a = 0,5 bis 1, b = 7 bis 8,5, c = 1,5 bis 3,0, d = 0 bis 0,15, e = 0 bis 2,5 und x = die elektrische Neutralität des Multimetalloxids gewährleistender stöchiometrischer Koeffizient von O2–, sowie 12 – b – 1,5·c = A und 0,5 ≤ A ≤ 1,5, 0,2 ≤ a/A ≤ 1,3, und 2,5 ≤ b/c ≤ 9, und deren Verwendung.
Abstract:
The invention relates to a centrifugal mist eliminator for separating liquid droplets from a gas stream, comprising: - a shell (1), which has a circular cross-section and a vertical longitudinal axis (11); - a an upper hood (2), which delimits the shell (1) at the top and has a gas outlet connecting piece (7) for the gas stream purified in the centrifugal mist eliminator; - a drip plate (8), which is disposed below the gas outlet connecting piece (7); - a lower hood (10), which delimits the shell (1) at the bottom and which has a liquid outlet connecting piece (4) for discharging the separated liquid droplets; and - an inlet (3) for feeding the gas stream, the inlet leading tangentially into the shell (1); the centrifugal mist eliminator being characterized in that at least two nozzles (9) for feeding a stabilizer liquid into the interior of the centrifugal mist eliminator are provided, the nozzle outlet (15) of each nozzle being disposed between the tangential inlet (3) and the drip plate (8) in the vertical direction, and the main spray direction (12) of the nozzles (9) being directed upward at an interior angle of 0 to 60° to the vertical longitudinal axis (11). The invention also relates to a method for separating liquid droplets from a gas stream in a centrifugal mist eliminator of this type.
Abstract:
processo para operação a longo prazo de uma oxidação de fase de gás parcial catalisada heterogeneamente de propeno a acroleína. é descrito um processo para operação a longo prazo de uma oxidação de fase de gás parcial catalisada heterogeneamente de propeno a acroleína, em que o propeno presente na mistura de entrada do gás de reação é parcialmente oxidado nesta mistura de gás através do catalisador de leito fixo que é acomodado em duas zonas de temperatura espacialmente sucessivas a, b, e operação a longo prazo, como uma medição para anular a redução na qualidade do catalisador de leito fixo, a temperatura de pelo menos uma das duas zonas de temperatura é aumentada, de maneira tal que a diferença t^ b^ - t^ a^ se torne crescentemente maior, onde t^ b^ é a temperatura da zona de temperatura b, e t^ a^ a temperatura da zona de temperatura a.