Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
  • C07C4/02—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by cracking a single hydrocarbon or a mixture of individually defined hydrocarbons or a normally gaseous hydrocarbon fraction
  • C07C4/025—Oxidative cracking, autothermal cracking or cracking by partial combustion
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
  • C07C5/42—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with a hydrogen acceptor
  • C07C5/48—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with a hydrogen acceptor with oxygen as an acceptor
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
  • C07C2521/02—Boron or aluminium; Oxides or hydroxides thereof
  • C07C2521/04—Alumina
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
  • C07C2523/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals
  • C07C2523/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals of the platinum group metals
  • C07C2523/42—Platinum
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
  • C07C2523/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals
  • C07C2523/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals of the platinum group metals
  • C07C2523/44—Palladium
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/20—C2-C4 olefins

Definitions

• a catalyst zone comprising at least a first catalyst bed which comprises platinum and palladium can provide superior performance to catalyst beds comprising platinum alone.
• the presence of palladium in the first catalyst bed has been found to provide improved tolerance of the catalyst to carbon monoxide present in the feed to the autothermal cracking reaction.
• the present invention provides a process for the production of an olefin, said process comprising passing a feedstream which comprises a paraffinic hydrocarbon, hydrogen and an oxygen-containing gas through a catalyst zone 10054(2) 2
• Carbon monoxide and hydrogen in the feedstream may be provided solely (or essentially solely) from recycle of carbon monoxide and hydrogen from the reaction product stream.
• carbon monoxide and hydrogen recycled from the reaction product stream may be supplemented by carbon monoxide and/or hydrogen from other sources, such as "fresh" hydrogen feed.
• the recycle stream may comprise up to 20vol% carbon monoxide in hydrogen.
• the feedstream to the process of the present invention may comprise at least 1% by volume of the total feedstream, for example, 1-10% by volume of the total feedstream, of carbon monoxide.
• the present invention provides a process for the production of an olefin, said process comprising passing feedstream which comprises a paraffinic hydrocarbon, hydrogen and an oxygen-containing gas through a catalyst zone which is capable of supporting combustion beyond the fuel rich limit of flammability to produce said olefin, said catalyst zone comprising at least a first catalyst bed and a second catalyst bed, said second catalyst bed being located downstream of the first catalyst bed, wherein the first catalyst bed comprises platinum and palladium and wherein the second catalyst bed is of a different composition to the first catalyst bed and either (i) comprises at least one metal selected from the group consisting of Mo, W, and Group EB, IIB, IIIB, rVB, VB, VIIB and VIII of the Periodic Table, or (ii) has the general formula
• the first catalyst bed according to the process of the (first or second aspect of the) present invention may also comprise a promoter.
• the promoter may be selected from the elements of Groups IHA, IVA and VA of the Periodic Table and the transition metals (other than platinum and palladium) and mixtures thereof.
• Preferred Group IIIA metals include Al, Ga, Li and Tl. Of these, Ga and In are preferred.
• Preferred Group IVA metals include Ge, Sn and Pb. Of these, Ge and Sn are preferred, especially Sn.
• the preferred Group VA metal is Sb.
• the atomic ratio of platinum metal to the promoter metal(s) may be 1 : 0.1 - 50.0, preferably, 1: 0.1 - 12.0, such as 1 : 0.3 -5.
• Suitable catalysts for use as the second catalyst bed include Ni/Sn, Co/Sn, Co/Cu, Cu/Cr, Ir/Sn, Fe/Sn, Ru/Sn, Ni/Cu, Cr/Cu, Ir/Cu, Fe/Cu and Ru/Cu.
• M 1 is selected from group IIIB
• M 2 is selected from group IIA
• M 3 is selected from group IB.
• M is yttrium
• M is barium
• M is copper.
• the catalyst (ii) is in the form of a perovskite-type structure.
• Perovskite- type structures include yttrium-barium-copper oxides YBa 2 Cu 3 O 7-S , lanthanum-strontium- iron oxides La 1-x Sr x Fe0 3- ⁇ , and lanthanum-manganese-copper oxides LaMn 1-x Cu x O 3- ⁇ , wherein x is in the range of 0.1-0.9 and ⁇ is typically in the range of 0.01-1, preferably in the range 0.01-0.25.
• Group VIII metals Preferably, the Group VIII metal is platinum.
• transition metal promoters examples include Cr, Mo, W, Cu, Ag, Au, Zn, Cd and Hg.
• Preferred transition metal promoters are Mo, Cu and Zn, especially Cu.
• Each catalyst employed in the catalyst zone may be unsupported or supported.
• an unsupported catalyst may be in the form of a metal gauze.
• at least one catalyst in the catalyst zone is a supported catalyst.
• each catalyst in the catalyst zone is a supported catalyst.
• the support used for each catalyst may be the same or different. Although a range of support materials may be used, ceramic supports are generally preferred. However, metal supports may also be used.
• the ceramic support may be any oxide or combination of oxides that is stable at high temperatures, for example, stable between 600°C and 1200°C.
• the ceramic support material preferably has a low thermal expansion co-efficient, and is resistant to phase separation at high temperatures.
• the form of the support is a monolith which is a continuous multi-channel ceramic structure.
• Such monoliths include honeycomb structures, foams, or fibrous pads.
• the pores of foam monolith structures tend to provide tortuous paths for reactants and products.
• foam monolith supports may have 20 to 80, preferably, 30 to 50 pores per inch.
• Channel monoliths generally have straighter, channel-like pores. These pores are generally smaller, and there may be 80 or more pores per linear inch of catalyst.
• Preferred ceramic foams include alumina foams.
• the size of the catalyst beds can vary from each other.
• the preferred relative lengths of the first catalyst bed to subsequent catalyst beds will generally depend on the loading of palladium on the first catalyst bed. In particular, as noted above, it has been found that relatively low palladium loadings on the first catalyst bed are sufficient to provide the desired tolerance, and higher levels of palladium can lead to significant levels of undesired side reactions, including increased formation of methane.
• oxygen-containing gas any suitable oxygen-containing gas may be used, such as molecular oxygen, air, and/or mixtures thereof.
• the oxygen-containing gas may be mixed with an inert gas such as nitrogen or argon.
• Hydrogen is co-fed with the paraffmic hydrocarbon and oxygen-containing gas into the reaction zone.
• the molar ratio of hydrogen to oxygen-containing gas can vary over any operable range provided that the desired olefin product is produced.
• the molar ratio of hydrogen to oxygen-containing gas is in the range 0.2 to 4, preferably, in the range l to 3.
• unsaturated hydrocarbons are provided as components of recycle streams from the autothermal cracking reaction itself. This allows a recycle stream to be separated from the product stream of the autothermal cracking reaction and recycled without treatment or with reduced treatment to remove unsaturated hydrocarbons, avoiding downstream separation steps and their associated costs.
• the feedstream is preheated prior to contact with the catalyst.
• the feedstream is preheated to temperatures below the autoignition temperature of the feedstream.
• a heat exchanger may be employed to preheat the mixed feedstream prior to contact with the catalyst.
• the use of a heat exchanger may allow the feedstream to be heated to high preheat temperatures such as temperatures at or above the autoignition temperature of the feedstream.
• high pre-heat temperatures is beneficial in that less oxygen reactant is required which leads to economic sayings.
• the use of high preheat temperatures can result in improved selectivity to olefin product. It has also be found that the use of high preheat temperatures enhances the stability of the reaction within the catalyst thereby leading to higher sustainable superficial feed velocities.
• the autoignition temperature of a feedstream is dependent on pressure as well as the feed composition: it is not an absolute value.
• a preheat temperature of up to 450° C may be used.
• Eleven alumina foam blocks (99.5% alumina supplied by Hi-tech Ceramics of Alfred, New York, block size 15mm diameter by 30mm deep, with nominal porosity of 45 pores per inch, total weight 60.42g) were impregnated with a solution containing 3.4 Ig of tetrammineplatinum(II) chloride (ex Johnson Matthey) in 150cm 3 of de-ionised water.
• the platinum- and copper-solutions were used alternately in the impregnation process. After immersion in the solution for ca. 5 minutes, excess solution was removed from the foam blocks and the foams were dried in air for 30 minutes at 12O 0 C then calcined at 45O 0 C for ca. 30minutes.
• the quartz liner had an inner diameter of 15mm and overall catalyst bed lengths ranged from 60mm to 100mm.
• the catalyst foam block was wrapped with ceramic paper to minimise the potential for reactant gas by- passing the catalyst bed.
• Reactant gases were fed to the reactor using Bronkhorst Hi-Tec thermal mass flow controllers. Gaseous effluent was analysed by gas chromatography, with residual oxygen being measured using a trace oxygen analyzer (Teledyne Analytical Instruments).
• Figure 8 shows the data for selectivity against ethane conversions for catalysts A to C 10054(2) 16
• catalyst C shows the highest selectivity at a particular ethane conversion.
• Experiment 5 60 mm bed of 3wt% platmum/0.2wt% palladium on alumina spheres
• Experiment 6 Sequential bed with 10 mm bed of 3wt% platinum/0.2wt% palladium on alumina spheres and 50 mm bed of 3 wt% platinum on alumina spheres The results from use of single beds comprising 3 wt% platinum on alumina spheres and comprising 3wt% platinum/0.2wt% palladium on alumina spheres and of a sequential bed comprising of 3wt% platinum/0.2wt% palladium on alumina spheres followed by 3wt% platinum on alumina spheres at a reaction pressure of 20 barg are shown in Figures 9 to 12.

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Citations (4)

• 2006
  • 2006-04-20 WO PCT/GB2006/001449 patent/WO2006117509A1/en active Application Filing
  • 2006-04-20 CN CNA2006800240352A patent/CN101213160A/zh active Pending

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