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
  • C10G25/00—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents
  • C10G25/02—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents with ion-exchange material
  • C10G25/03—Refining of hydrocarbon oils in the absence of hydrogen, with solid sorbents with ion-exchange material with crystalline alumino-silicates, e.g. molecular sieves

Definitions

• the invention relates to the separation of hydrocarbons and more particularly to a process for purifying a hydrocarbon cut from aromatic compounds it contains. More specifically, the invention deals with the possibility of carrying out the operation cited by adsorption on a molecular sieve. She has for more specific purpose the purification of normal paraffin sections containing as impurities of aromatic compounds. It is of primary importance that normal paraffins which are widely used chemicals also be as pure as possible with regard to their content of aromatic compounds.
• the paraffins in question form the basis for synthesizing molecules detergents such as alkyl sulfonates or alkylarylsulfonates. Apart from this use in the detergents industry, paraffins know uses various as solvents or as chemical intermediates, for example, in aromatization or alkylation reactions.
• paraffins are often polluted by compounds aromatic is to be sought in the fact that they are produced from cuts gasoline, kerosene or diesel fuel formed from very different molecules including mention may be made of aromatic compounds, naphthenic compounds, compounds olefinic or linear or branched saturated compounds.
• paraffinic cups serving, among other things, the production of detergent molecules which tend to become more and more severe; current values report less than 1,000 ppm.
• US Patent 3,969,223 discloses a method of separating an olefin from a mixture of hydrocarbons consisting of olefins and saturated compounds using a type X zeolite treated for a certain time in a solution of soda then washed; the purpose of this treatment is to extract a small fraction of the silica and the alumina present in the sieve or in the agglomeration binder (consisting of silica, alumina or a silica-alumina) and, as a claimed side effect, to bring the ratio NA 2 O / Al 2 O 3 as close to 1 as possible.
• Another process for the separation of hydrocarbons relates to adsorption on activated carbon or carbon molecular sieve of 1,3-butadiene from a mixture comprising at least one other C4 hydrocarbon and is described in US 4,567,309 on behalf of UOP.
• the following pairs are cited: 1,3-butadiene / n-butane; 1,3-butadiene / isobutylene; 1,3-butadiene / trans-butene or 1,3-butadiene / cis-butene.
• zeolites are capable of selectively fix certain molecules. In some cases, selectivity is practically total, which means that in a mixture of two types of molecules, one can be almost completely adsorbed and the other, almost completely excluded: it is this property which has earned zeolites the term sieve which arises from the fact that zeolites are, in most of the case, crystalline aluminosilicates formed by the condensation of tetrahedrons of silica and alumina tetrahedra using bridging oxygen. The arrangement of these species in space, requires the arrangement of pores and cavities whose dimensions are particularly uniform. Only molecules whose size is smaller than the pore diameter can penetrate the crystal and adsorb.
• the pores vary between around 3 and 8 Angstroms (0.3 to 0.8 nm) depending on the types of zeolites, but for a given zeolite, the pores have a perfectly calibrated size.
• a description of these products can be found in "Molecular Sieves Zeolites" by D.W. BRECK, John Wiley and Sons, 1974.
• Other products also exist which have molecular sieving properties but whose use rather covers catalysis, such as offretite (OFF), omega (MAZ), ferrierite (FER) or mordenite (MIR).
• zeolites of the faujasite type to which the X and Y belong are very often used because of their large pore volume and size of pores which allows the penetration of relatively large molecules such as aromatics, even polyaromatics.
• the interest of these solids is based on the fact that we can vary the Si / Al ratio in large proportions, which modifies, sometimes considerably, the molecule-crystal interactions or within the structure.
• Type X zeolites including pores have an opening of 8 Angstroms (0.8 nm)
• species such as n-dodecylbenzene, naphthalene or dibenzothiophene in relation to molecules, either paraffinic or naphthenic
• SATTERFIELD C.N and CHEN C.S. AichE Journal, vol. 18, N ° 4, p. 720, 1972, or AHMETOVIC D. and SVEL-CEROVECKI S., Zeolites, Synthesis, Technology and Applications, 1985, p. 683.
• the adsorbents used until now for the elimination of the compounds aromatics are therefore molecular sieves of the faujasite type which are called commonly in the 13X or 10X profession.
• These materials made up of the arrangement of silicon oxide and aluminum oxide tetrahedra possess a negative electric charge due to the presence of aluminum, a trivalent element, instead of silicon, a tetravalent element.
• the charge in question is compensated by a cation, generally chosen from alkaline elements or alkaline earth elements; these cations are naturally hydrated in the cavities of zeolite and can be exchanged by simple contact thereof with a solution of another cation, in the form of chloride, nitrate, oxyalate, acetate, sulfate.
• 13X molecular sieves or 10X refer to faujasites whose Si / Al ratio is between 1.2 and 1.5, usual composition range for these products.
• the 13X designation refers more particularly to a solid whose compensating cation is sodium and the designation 10X to a solid whose compensating cation is calcium.
• the faujasites which are the means of the invention are used in the form of beads or granules. We prefer small diameter balls (0.5 - 1 mm).
• the industrial treatment is preferably carried out by percolation on columns, which makes it possible to adjust the conditions for obtaining paraffins at degree of purity that is desired, possibly at aromatic contents undetectable by ordinary means of analysis.
• Saturated faujasites from aromatic compounds can be regenerated according to well known methods of those skilled in the art. Paraffinic cuts from separation processes MOLEX particularly benefit from the treatment according to the invention.
• a zeolite of the faujasite type and an Si / Al ratio equal to 1 is synthesized according to Example 1 of FR-A-2,669,242 (CECA SA) in which a gel of composition is prepared: 4.87 Na 2 O 1.63 K 2 O-2SiO 2 -Al 2 O 3 -H 2 O which is subjected first of all to a ripening of about twenty hours at 50 ° C. and then to a crystallization of 4 hours at 100 ° C. The crystals after filtration and washing are identified by X-ray diffraction as being made up of pure faujasite.
• the solid thus obtained is exchanged with calcium or with lithium by making several contacts with molar solutions of these salts, at a temperature of the order of 70 ° C.
• the solids thus exchanged are then calcined at 550 ° C for 2 hours under an atmosphere of dry nitrogen, then stored away from air. Simultaneously, the calcination of a 13X zeolite from CECA SA marketed under the same conditions is carried out.
• Another fraction of the commercial zeolite 13X is exchanged with salts of calcium, barium and potassium by making several contacts with solutions 1 molar, and this, at a temperature of about 70 ° C.
• the solids thus obtained then undergo the same calcination treatment as the samples of example 2.
• the 13X and FAU 1 zeolites exchanged with calcium (called respectively CaX and CaFAU 1) are brought into contact with the mother solution under the conditions already described.
• the 13X zeolites exchanged with potassium and barium (also called KX and BaX respectively) are also brought into contact with the mother solution.
• the selectivity results are reported in the table below: Adsorbent Selectivity CaX 610 KX 500 BaX 360 CaFAU1 1200

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Steroid Compounds (AREA)
• Treatment Of Liquids With Adsorbents In General (AREA)
• Compounds Of Unknown Constitution (AREA)
• Silicates, Zeolites, And Molecular Sieves (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Saccharide Compounds (AREA)

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• 1996
  • 1996-02-21 FR FR9602151A patent/FR2745006B1/fr not_active Expired - Fee Related
• 1997
  • 1997-02-11 DE DE69703757T patent/DE69703757T2/de not_active Expired - Lifetime
  • 1997-02-11 EP EP97400307A patent/EP0791642B1/fr not_active Expired - Lifetime
  • 1997-02-11 DK DK97400307T patent/DK0791642T3/da active
  • 1997-02-11 ES ES97400307T patent/ES2153166T3/es not_active Expired - Lifetime
  • 1997-02-11 AT AT97400307T patent/ATE198347T1/de active
  • 1997-02-13 KR KR1019970004207A patent/KR100443293B1/ko not_active IP Right Cessation
  • 1997-02-18 CA CA002197899A patent/CA2197899C/fr not_active Expired - Fee Related
  • 1997-02-21 CN CN97102815A patent/CN1102637C/zh not_active Expired - Fee Related
  • 1997-02-21 JP JP05394397A patent/JP3855137B2/ja not_active Expired - Fee Related
  • 1997-02-21 US US08/804,480 patent/US5731488A/en not_active Expired - Lifetime
• 2001
  • 2001-02-20 GR GR20010400264T patent/GR3035433T3/el unknown

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