Classifications

• • 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
  • C10G35/00—Reforming naphtha
  • C10G35/04—Catalytic reforming
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/90—Regeneration or reactivation
  • B01J23/96—Regeneration or reactivation of catalysts comprising metals, oxides or hydroxides of the noble metals
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
  • B01J38/12—Treating with free oxygen-containing gas
  • B01J38/20—Plural distinct oxidation stages
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
  • B01J38/12—Treating with free oxygen-containing gas
  • B01J38/22—Moving bed, e.g. vertically or horizontally moving bulk
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J38/00—Regeneration or reactivation of catalysts, in general
  • B01J38/04—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst
  • B01J38/42—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using halogen-containing material
  • B01J38/44—Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst using halogen-containing material and adding simultaneously or subsequently free oxygen; using oxyhalogen compound

Definitions

• the invention relates to the regeneration of reforming catalysts and catalysts for the production of aromatic hydrocarbons.
• these catalysts are used for the conversion of naphthenic or paraffinic hydrocarbons, capable of being converted by dehydrocyclization and / or dehydrogenation, during the reforming or the production of aromatic hydrocarbons (for example the production of benzene, toluene, ortho-, meta- or paraxylenes).
• aromatic hydrocarbons for example the production of benzene, toluene, ortho-, meta- or paraxylenes.
• Coke or coke precursors are compounds consisting essentially of carbon and hydrogen. They are deposited on the active sites of the catalyst.
• the molar ratio H / C of the formed coke and its precursors generally varies between 0.3 to 1.0.
• the carbon and hydrogen atoms generally form condensed poly-aromatic structures whose degree of crystalline organization is variable depending on the nature of the catalyst and the operating conditions of the reactors.
• the conversion selectivity of the hydrocarbons to coke is very low, the coke and coke precursors accumulated on the catalyst can become important. For fixed bed units, these levels are generally between 2.0 and 35.0% by weight. For circulating bed units, these contents are generally less than 10.0% by weight.
• Coke deposition, faster at low pressure also requires a faster regeneration of the catalyst. Current regeneration cycles can go down to 2 or 3 days.
• Patents EP0872276B and EP0872277B deal with the regeneration of reforming catalysts. These are processes for regenerating a reforming catalyst comprising successive stages of combustion, oxychlorination and calcination.
• the method according to the present invention comprises at least two combustion beds A1 and A2 and differs in particular from the processes described in these two patents EP0872276B and EP0872277B by recycling a portion of the effluent of the oxychlorination zone via a blower (Blower according to the English terminology) to the last bed A2 combustion.
• the invention relates to a method for regenerating a catalyst for the production of aromatic hydrocarbons or for reforming comprising a combustion step in a zone A comprising at least 2 beds A1 and A2, an oxychlorination step in a zone B, an calcination step in a zone C.
• the effluent gas from the oxychlorination zone is partially recycled via at least one washing section D to the inlet of beds A1 and A2.
• the effluent gas from zone B is partially recycled to the combustion bed A2 via a fan but without passing through said washing section D, and partly towards the entrance to zone B via said blowing but without going through said washing section.
• the invention also relates to the enclosure in which this process takes place.
• the catalyst to be regenerated generally comprises a support, said support comprising at least one refractory oxide and / or one or more zeolites. It comprises at least one noble metal, preferably platinum and at least one halogen. It optionally comprises one or more additional elements selected from the group consisting of elements of group IA, MA, lanthanides, elements of group IV A, preferably silicon and / or tin, elements of group IMB, elements Group III A, preferably indium, Group VA elements, preferably phosphorus and Group VIIB elements, preferably rhenium (group numbers correspond to the CAS classification in CRC Handbook of Chemistry and Physics, publisher CRC Press, Editor-in-Chief DR Lide, 81 st edition, 2000-2001).
• the catalyst comprises at least platinum, chlorine and an alumina support.
• the objective is therefore to minimize the particle size during the preparation and to maintain this state of high dispersion.
• the presence of chlorine in sufficient quantity is an answer to this problem.
• the inventors have thus demonstrated that the recycling of part of the effluent of the oxychlorination zone via a blower (blower according to the English terminology) partly to the last combustion bed A2 and partly to the Entry of the oxychlorination zone B provides chlorinating agent, especially on the A2 bed.
• This intake reduces the elution of chlorine and reduces the consumption of chlorinating agent.
• these recycling operations make it possible to reduce the sintering of platinum and thus promote its efficient redispersion during step B of oxychlorination.
• the combustion zone A comprises at least 2 combustion beds A1 and A2, preferably 2 beds A1 and A2. Said beds are preferably mobile and radial.
• Zone B oxychlorination comprises at least one bed. These beds are usually mobile. Preferably, said beds are also axial.
• the zone C of calcination comprises at least one bed. These beds are usually mobile. Preferably, said beds are also axial.
• the catalyst is generally treated under a pressure of 3 to 8 bar and at a temperature of between 350 and 550 ° C. by a combustion gas comprising 0.01 to 1.3% oxygen by volume and circulating co-current of the catalyst.
• the gas in the bed A1 generally comes from mixing a portion of the gas from the oxychlorination zone B with a portion of the gas from the bed A2.
• the catalyst is generally treated under a pressure of 3 to 8 bars. This pressure is generally substantially equal to that prevailing in the bed A1.
• the temperature in the bed A2 is generally at least 20 ° C. higher than the temperature prevailing in the bed A1.
• the combustion in the bed A2 generally takes place in the presence of the gas having circulated through the bed A1 and in the presence of a part of the effluent coming from the outlet of the oxychlorination zone B.
• an inert gas of preferably add nitrogen may optionally be added in the bed A2.
• an additional dry air may optionally be added in the bed A2.
• the catalyst is generally treated countercurrently with a mixture of a gas comprising oxygen which originates from:
• an additional oxygen preferably in the form of air
• this gas mixture supplying the oxychlorination zone generally comprises an addition to at least one chlorinating agent.
• this gas mixture feeding the oxychlorination zone generally comprises a makeup water or water precursor. Part of the gas from the oxychlorination is, via a blower, recirculated to the bed A2.
• the chlorinating agent (s) are generally selected from the group consisting of chlorine, hydrogen chloride and halogenated hydrocarbons comprising less than 4 carbon atoms and 1 to 6 chlorine atoms.
• the oxychlorination zone may be C 2 Cl 4 , CCI 4 or any known chlorinating agent in these regeneration processes to release chlorine. They are introduced preferably in a mixture with the gas comprising oxygen.
• the oxychlorination zone is composed of mobile and axial beds, it is generally introduced into the lower part of the oxychlorination zone so that it flows against the current of the catalyst.
• the molar ratio H2O / HCl in zone B is generally between 1 and 50, preferably between 1 and 40, and very preferably between 1 and 30.
• the oxychlorination step takes place in the presence of a gas generally comprising less than 40%, preferably less than 30%, preferably less than 21% oxygen volume, very preferably between 4% and 21%. oxygen volume, more preferably between 10% and 21% oxygen and generally at least 50 ppm by weight of chlorine, at a temperature generally between 350 and 600 0 C, preferably between 350 and 550 0 C more preferably between 450 and 550 ° C, very preferably between 490 and 550 ° C.
• the pressure in this zone is generally from 3 to 8 bars for the moving bed processes, in particular for the reforming processes. low pressure.
• the residence time of the catalyst in the oxychlorination step is generally less than 3 hours, preferably between 30 minutes and 3 hours.
• At least one oxygen booster is introduced into the oxychlorination zone.
• a chlorinating agent and a water precursor are introduced into the oxychlorination zone.
• the oxygen present in the oxychlorination zone then comes from the gas coming from the calcination zone and from recycling the effluent from the oxychlorination zone to the inlet of said oxychlorination zone.
• the gas supplying the oxychlorination zone results from the mixing of the gas coming from the calcination zone, with the addition of the chlorinating agent (s), with makeup water or precursors of water and with the gas or gases comprising oxygen introduced into the oxychlorination zone.
• the gas or gases comprising oxygen may be a part of the gases from the last combustion bed washed, preferably dried and supplemented with an oxygen supplement and the recirculation gas of a portion of the effluent of the oxychlorination zone via a blower to the oxychlorination zone.
• the calcination step is carried out in zone C, in which the catalyst is treated for 20 to 160 minutes at a temperature of between 350 and 600 ° C. under a pressure of between 3 and 8 bar, by a mixed dry air booster. possibly with a part of the gases coming from the washing section and the possible drying zone.
• the feed gas of the calcination zone generally does not comprise more than 1% volume of water, preferably not more than 0.1% volume of water. Generally, it comprises at most 21% oxygen volume. It generally flows countercurrently in the case of moving bed processes with axial calcination zone. According to one variant, the only gas booster comprising oxygen is produced at the inlet of the calcination zone.
• the gaseous effluent from the bed A2 is generally sent, mixed with a portion of the gaseous effluents from the oxychlorination zone B, to the washing section D. Part of the effluent of this washing section is purged and the other part is generally sent to a drying section E and is generally sent to a compressor.
• the compressor effluent is generally sent partly to the combustion beds A1 and A2 and possibly partly to the oxychlorination and calcination zones.
• the catalyst is in a moving bed in each of the zones A, B and C.
• the gas in the oxychlorination zone results from mixing the gas coming from the calcination zone C with: minus a chlorinating agent
• the gas in the calcination zone comes from a booster of dry air mixed with a part of the previously washed, dried and compressed gases which come from the combustion bed A2.
• the only oxygen additions preferably in the form of air, are generally at the beginning of the last combustion bed A2, at the inlet of the oxychlorination zone and at the inlet of the calcination zone, preferably the only oxygen additions are at the inlet of the calcination and oxychlorination zones, very preferably a single oxygen booster is performed at the inlet of the calcination zone.
• the effluent gas from the oxychlorination zone is recycled in part via at least the washing section D, the drying section E and the compressor to the inlet of the combustion beds A1 and A2.
• the effluent gas from the oxychlorination zone is partially recycled to the combustion bed A2 and to the inlet of the oxychlorination zone, this recycling being carried out via a blower and without passing through the drying sections. washing and by the compressor.
• the invention also relates to an enclosure for carrying out the method, comprising a combustion zone A comprising 2 combustion beds (A1) and (A2) in series, at least one oxychlorination zone (B) comprising at least 1 bed of oxychlorination and at least one calcining zone (C) comprising a calcination bed.
• the enclosure comprises means for the circulation of the catalyst successively through the n combustion beds, the oxychlorination zone and the calcination zone.
• the enclosure comprises a point for sampling a portion of the gas from the oxychlorination zone, said sampling means being connected to a fan, said fan being connected downstream to at least one first recycling line, a portion of the gases to the last combustion bed A2 and at least a second recycle line of another portion of the gases to a point of introduction of gas into the oxychlorination zone.
• This point of introduction is located below the sampling point of the oxychlorination zone, this second recycling line comprising at least one point of introduction of water or precursors of water, at least one furnace and at least one a point of introduction of chlorinating agents.
• the second recycling line comprises, upstream of the blower, a gas sampling point in order to recirculate a portion of the gases via a washing section D, the effluent of the washing section being partly purged and then preferably sent to a drying section E, then a compressor, the compressor effluent gases being partly recycled at least to the combustion beds A1 and A2.
• the enclosure includes a means of removing a portion of the gas at a first point of the last combustion bed A2, said sampling means being at least connected to the washing section.
• the enclosure comprises a plate or any other means for separating the combustion zone and the oxychlorination zone in order to avoid the mixing of the gases resulting from the combustion and the gases resulting from the oxychlorination.
• a plate or any other means is generally arranged for separating the zones of combustion and oxychlorination.
• the gases resulting from the calcination can generally pass freely in the zone of oxychlorination.
• the second recycling line comprises, upstream of the blower, a gas sampling point in order to recirculate a portion of the gases via a washing section D, the effluent of the washing section being partially purged before moving , via a drying section E, then via a compressor, the compressor effluent gases being partly recycled at least to the combustion beds A1 and A2 and partly to the oxychlorination zone and to the calcination zone.
• Figure 1 shows an embodiment of the invention.
• Figure 2 illustrates the impact of chlorine injection on platinum sintering as a function of time.
• the enclosure (2) comprises a combustion zone A, an oxychlorination zone B and a calcination zone C.
• Combustion zone A has two combustion beds A1 and A2.
• the catalyst is introduced via line 1 at the top of the chamber F and then descends by gravity into the combustion bed A1 then A2 and then via the line 3 of the bed A2 to the oxychlorination zone B and then to the calcination zone C then comes out of the speaker via line 4.
• the bed A1 has a gas inlet flowing via line 10, and a gas outlet flowing via line 24.
• the bed A2 has a gas inlet flowing via the line 23, and a gas outlet flowing via the line 5 and then via the cooler 36.
• Zone B comprises a gas inlet flowing via line 8, and a gas outlet flowing via line 17.
• an addition of chlorinating agent circulates via line 6 in mixture with the gas flowing via line 28 to supplying the oxychlorination zone via the line 8.
• an addition of water or a precursor of water circulates via the line 7 and in mixture with the gas flowing via the line 25 flows via the line 28 and then by a furnace 19 to be introduced into oxychlorination via line 8 in mixture with the addition of chlorinating agent flowing via line 6.
• Zone C has a gas inlet flowing via line 14.
• Part of the effluent gas from the oxychlorination zone B flows via the line 17 and is cooled by the cooler 35 and then flows via the line 33, then by a fan 18, then by the line 20 and then by the line 30 and then by the line 31 and then line 23.
• Recirculation 2 Part of the effluent gas from the oxychlorination zone B flows via the line 17 and is cooled by the cooler 35 and then flows via the line 33, then by a fan 18, then by the line 20 and then by the line 30 and then by the line 31 and then line 23.
• Part of the effluent gas from the oxychlorination zone B circulates via the line 17 is cooled by the cooler 35 and then flows via the line 32 to be mixed with the gas from the combustion bed A2 which circulates via the line 5.
• This mixture passes through the washing section D via the line 37 and is partly purged via the line 29 and the other part sent to the drying section E and then to the compressor 26.
• the effluent of the drying section E flows via the line 38 and then partly via the line 9 and partly via the line 27 and then by a valve 22 and is sent to the A2 bed via the line 30 and then the line 31 and then the line 23.
• the other part of the gas mixture circulating via line 9 is sent via line 10 to an oven 13 and is then injected to the first combustion bed A1.
• the effluent gas from A1 passes via line 24 and is mixed with the gas passing through line 31 to feed the second combustion bed via line 23.
• the gas flowing via line 31 corresponds to the mixture of the gas flowing via line 30 with the optional makeup 21 of gas comprising oxygen.
• Recirculation 4 A booster of chlorinating agent is injected via line 6 and is mixed with the gas from line 28 to be injected via line 8 to the oxychlorination zone.
• Recirculation 5 The gas flowing via line 38 is partially recycled via line 9 to the combustion beds A1 and A2 and partly via line 11 to the calcination zone and to the oxychlorination zone.
• Part of the gas flowing via line 11 is sent to zone B via line 15 and then 25 and 28 and then 8. Another part may be mixed with the dry air make-up circulating via line 12, passed through the oven 16 and be sent for calcination via line 14. Recirculation 6
• a portion of the oxychlorination output gas is recirculated to the inlet of the oxychlorination zone via the line 17 and then via the cooler 35 and then via the line 33 and then via the blower 18, then via the lines 34 and 25 then 28 then via oven 19 and then via line 8.
• FIG. 1 corresponds to the diagram according to the invention used for the simulation carried out with the software Pro II.
• the temperature of the gases injected at the inlet of the calcination zone and at the inlet of the oxychlorination zone is 510 ° C. for the basic scheme and the scheme according to the invention.
• the basic diagram illustrates the case where neither the recirculation via the blower of the effluent from the oxychlorination zone to the inlet of the second combustion bed, nor the recirculation of the effluent from the oxychlorination zone to the entry of the oxychlorination zone are carried out (See the zero flow of gases flowing via line 20, 33 and 34).
• the diagram according to the invention illustrates the case where these two recycling operations are carried out.
• Tests were performed in a fixed bed reactor to characterize the influence of the presence of chlorine in the second combustion bed. This test is indeed representative of the conditions recorded in the second combustion bed.
• a platinum catalyst on a chlorinated alumina support whose initial chlorine content is 1.1% by weight is tested under an air atmosphere with 10,000 ppm of water, a flow rate of 2000 Nl / kg / h and at a temperature of 650 ° C. The test is carried out over a period of 60 hours.
• the chlorine is injected into the reactor in order to have a stable chlorine content throughout the test of 1.1% by weight (+/- 0.2% by weight).
• Accessibility in the sense of the present invention is the amount of platinum accessible to the charge to be converted relative to the total amount of platinum present on the catalyst.
• the reduction in accessibility corresponds to platinum sintering.
• the measurement of the accessibility of the platinum is carried out by H 2 O 2 titration.
• the H 2 / O 2 titration consists in measuring the volume of oxygen consumed by the reaction (1) after a hydrogen reduction stage of the catalyst.
• Pt 3 denotes the superficial atoms of platinum.
• V M molar volume of the gas (24400 ml / mol) at 25 ° C.
• Figure 2 shows a lower accessibility over time therefore a greater sintering platinum without chlorine injection.

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• 2007
  • 2007-10-26 FR FR0707607A patent/FR2922786B1/fr not_active Expired - Fee Related
• 2008
  • 2008-10-17 EP EP08871120.5A patent/EP2205699B1/fr active Active
  • 2008-10-17 CN CN2008801128768A patent/CN101835877B/zh active Active
  • 2008-10-17 WO PCT/FR2008/001460 patent/WO2009090339A1/fr not_active Ceased
  • 2008-10-17 US US12/739,187 patent/US8680000B2/en active Active
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