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
  • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
  • C10G65/02—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only
  • C10G65/04—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including only refining steps
  • C10G65/043—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including only refining steps at least one step being a change in the structural skeleton
• • 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
  • C10G2400/10—Lubricating oil

Definitions

• the present invention relates to a process for producing lubricating oils from waste or virgin polymers, especially olefins polymers such as polyethylene.
• the present invention is a process for converting polymers to lubricating oils, said process comprising:
• the polymer used is preferably a polyolefin and can be polyethylene such as eg linear low density or high density polyethylene, polypropylene, EPDM, scrap rubber and the like. These can be waste polyolefins or virgin polyolefins which are of scrap value and recovered from processes using polyolefins during fabrication or other processing methods.
• the fluidised bed used for thermally cracking the polymer is inert under the reaction conditions ie to the hydrocarbon reactants and the products produced therefrom.
• the fluidised bed is suitably formed from a solid particulate material selected from quartz sand, silica, ceramics, carbon black, aluminosilicates and the like.
• the fluidised bed material is catalytically inert towards the polymer and suitably comprises particles of a size capable of being fluidised, for example 100 to 2000 ⁇ m.
• the thermal cracking process is suitably carried out substantially in the absence of a catalyst at a temperature from 300 to 690°C, preferably from 300 to 550°C and is suitably carried out using a fluidising gas which is also inert under the reaction conditions, eg nitrogen.
• a fluidising gas which is also inert under the reaction conditions, eg nitrogen.
• waxy product is meant here and throughout the specification that the product has a molecular weight which is significantly lower than the starting olefin eg below 3500 but is at least 100, preferably greater than 300 as determined by GPC methods.
• the waxy product formed in step (a) may be contaminated with heteroatomic compounds or polynuclear aromatic compounds depending upon the nature of the starting polymer.
• the heteroatomic compounds may be open chain or heterocyclic compounds. Where such compounds are present in the waxy product from step (a) it would be necessary to subject this waxy product to a hydrotreating step.
• the hydrotreating step suitably comprises reacting the product from the first step (a) with hydrogen and a conventional hydrotreating catalyst such as cobalt/molybdenum, nickel/molybdenum or a combination of cobalt/nickel/molybdenum supported on eg alumina.
• the hydrotreating reaction is suitably carried out under standard, commercially accepted conditions eg temperature of 280-400°C, a liquid hourly space velocity (LHSV) in the range of 0.1 to 5 h ⁇ 1, pressure from 30-200 bar and hydrogen gas rates from 100 to 5000 NLL ⁇ 1.
• LHSV liquid hourly space velocity
• the process is preferably carried out using a nickel/molybdenum catalyst supported on alumina in the presence of hydrogen.
• the hydrotreatment process is designed to remove substantially all of the heteroatomic compounds and the polynuclear compounds from the product of step (a).
• the waxy product contains no more than 5 ppm of nitrogen and no more than 20 ppm of sulphur. It is however, preferable that the waxy product contains no more than 2 ppm of nitrogen and no more than 5 ppm sulphur.
• the polynuclear aromatic content of the waxy product is suitably less than 5%w/w, preferably less than 2%w/w.
• the desired waxy product is recovered from the hydrotreatment step by distillation.
• the waxy product from step (a), or, where the hydrotreatment step (b) is used,from step (b) is then subjected an isomerization step (c).
• the isomerization is carried out in the presence of a isomerization catalyst comprising a hydrogenating metal component from Group VI and/or a Group VIII metal supported on a refractory metal oxide which should preferably be doped with halide ions.
• the metal component of the catalyst used is suitably selected from the Group VIII metals, and is preferably platinum.
• the refractory metal oxide support used is suitably a transition metal oxide such as eg ⁇ -alumina or ⁇ -alumina which is suitably doped with a halide ion, preferably a fluoride ion.
• fluorided alumina is a preferred support in the Case where step (c) is used.
• the isomerization catalyst may have to be suitably sized to meet handling considerations.
• the catalyst may be ground up using eg a pestle and mortar and then screened to obtain the desired size. Such sizing will ensure that the catalyst has acceptable flow characteristics for the reaction depending upon the type of reactor used.
• the isomerization catalyst is suitably activated prior to use, eg by heating at elevated temperature in the presence of hydrogen.
• the activation is suitably carried out at a temperature from 350 to 520°C, preferably from 400 to 510°C.
• the isomerization step is carried out in the presence of hydrogen used at pressures of 30 to 200 bar, preferably from 60 to 100 bar. Hydrogen gas rates of 150 to 2000 NLL ⁇ 1, and an LHSV in the range of 0.1 to 10 h ⁇ 1, preferably 0.5 to 2h ⁇ 1 can be used in this step.
• the isomerization treatment is suitably carried out at a temperature in the range from 270 to 400°C, preferably from 300 to 360°C.
• the oil so formed generally has a high viscosity index eg in excess of 130.
• the lubricating oil so produced can be used in eg automotive applications, and can be subjected to further hydrofinishing processes using conventional catalysts such as cobalt/molybdenum or nickel/molybdenum on alumina supports. Such conventional techniques enable removal of undesirable impurities from the lubricating oil product thereby further improving product quality.
• a hydrocarbon wax (prepared by cracking high density polyethylene at 500-550°C in a sand bed fluidised using nitrogen gas) was distilled to give a fraction with a boiling range of about 190°C to 712°C. This was isomerized over a platinum on fluorided alumina catalyst made by first fluoriding a platinum loaded 1/16 inch ⁇ -alumina extrudate (0.32 %w/w platinum) using an aqueous ammonium fluoride solution (insipient wetness) after which the fluorided metal loaded extrudate was dried under vacuum on a rotary evaporator at 80°C for 50 minutes.
• the metal loaded fluorided extrudate was calcined in flowing air (1000 ml/min) as follows: hold at 120°C for 2h; heat from 120 to 515°C at 10°C/min and from 515 to 550°C at 1°C/min; hold at 515°C for 25 min; cool to room temperature at natural cooling rate. It was then crushed and sieved (0.5-1.4mm) to produce a catalyst with a fluoride content of 5.9%w/w.
• the catalyst thus sized was activated by heating at 510°C in flowing hydrogen at 12 bar in the following manner: room temperature to 510°C at 2.5°C/min; hold for 2h.
• This catalyst was initially used to process a commercially available hydrocarbon wax (Huels, Vestowax SP 1044) prior to switching over to the polyolefin derived waxy product after 686 h on stream.
• the data presented in the Table below were obtained using the polyolefin derived waxy product as feed.
• a hydrocarbon wax was prepared by cracking linear low density polyethylene (LLDPE) at 500-550°C in a sand bed fluidised using nitrogen gas. This was distilled to give a fraction with a boiling range of about 190°-750°C and was isomerized over a platinum on alumina catalyst prepared and activated as in Example 1 above. The catalyst was again initially used to process Vestowax SP 1044 (ex Chemische Werke Huels) prior to switching over to the LLDPE derived waxy product after 144 hours on stream. The data presented in Table below were obtained using the LLDPE derived waxy product as feed.
• LLDPE linear low density polyethylene

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Lubricants (AREA)

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Cited By (37)

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• 1993
  • 1993-04-14 GB GB939307652A patent/GB9307652D0/en active Pending
• 1994
  • 1994-03-30 EP EP94302304A patent/EP0620264A3/fr not_active Withdrawn
  • 1994-04-12 JP JP7323194A patent/JPH073268A/ja active Pending

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