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
  • C10G25/003—Specific sorbent material, not covered by C10G25/02 or C10G25/03

Definitions

• the present invention relates to a process for the at least partial removal of trace elements from hydrocarbon mixtures by treating these mixtures with a synthetic polymer which contains thiourea groups.
• the process is particularly important for the simultaneous extensive removal of mercury and a considerable reduction in the arsenic and lead content.
• Such polymers with thiourido groups can be regenerated with sodium sulfide.
• LDF Light Distilled Fraction or Light Distilled Feedstock
• Such mixtures consist essentially of hydrocarbons, although small amounts of oxygen-containing, sulfur-containing or nitrogen-containing compounds may be present.
• the composition of such mixtures is known to the person skilled in the art.
• the present invention is preferably directed to the treatment of natural gas condensates.
• Hydrocarbon mixtures of the type mentioned are subjected to further reactions and catalytic processes in petrochemical plants and refineries, such as steam cracking or catalytic cracking (FCC); the valuable products obtained during cracking are in turn subjected to further catalytic reactions.
• FCC catalytic cracking
• mercury, arsenic, lead and phosphorus may be mentioned, of which mercury and arsenic are of particular importance.
• the toxic effects of mercury and arsenic are known.
• the mercury is a highly corrosive metal, so that considerable corrosion damage can occur in technical apparatus, for example due to amalgam formation.
• Even in katalyti Processes such as hydrogenation, polymerization and others can cause catalyst deactivation or an undesirable shift in the catalytic effects due to mercury through amalgam formation or through the formation of intermetallic phases.
• the arsenic can also cause catalyst damage through the formation of intermetallic phases.
• the trivalent arsenic also has a strong reducing power, which causes, for example, catalysts for olefin polymerization to lose their activity.
• J. Chromatogr. 102 (1974), 443-51 discloses a process in which a polymer resin with SH groups which acts selectively for mercury is used. This selectively acting resin, however, only responds to mercury in ionic form, so that elemental mercury present in such waste water has to be converted into the ionic form in an additional process step before being treated with such a resin.
• SiO2 in the form of silica gel, diatomaceous earth, glass or the like. also requires chemical activation, which is cumbersome and not very effective, so that such use can be disadvantageous.
• Zeolites treated with sulfides or metal iodides only show a significant binding capacity for mercury from gases at process temperatures of around 250 ° C (Z. Chem. 1977 , 85).
• EP 319 615 describes a process for removing mercury from liquid organic media with the aid of a solid absorber which contains active SH groups, in which more than 97% of the mercury present in the starting medium can already be removed.
• a process for the at least partial removal of trace elements from hydrocarbon mixtures has now been found, which is characterized in that these hydrocarbon mixtures are treated at a temperature of from -20 ° C to + 70 ° C with a synthetic polymer which contains thiourea groups.
• Oxidative pretreatment of the liquid hydrocarbon mixture to be used is not necessary in the process according to the invention.
• the method according to the invention allows a lowering of also higher mercury contents of 50 ppb and higher to a mercury content below 1 ppb; at the same time, for example, the arsenic content can be reduced to 50%, often to 20% or less, of the feed concentration. Furthermore, the lead content is reduced to 60% or less of the feed concentration.
• the polymer containing thiourido groups is insoluble in the hydrocarbon mixtures to be treated and has, for example, a backbone of acrylic monomers / divinylbenzene crosslinking agents, phenols / formaldehyde or styrene / divinylbenzene, preferably a backbone of styrene and divinylbenzene.
• the crosslinker content is, for example, 2-85%, preferably 5-10%, expressed in mol% of divinylbenzene crosslinker, based on the sum of the number of moles of all monomers.
• the frameworks of such polymers can be produced in a manner familiar to the person skilled in the art with a gel-like or macroporous consistency. A macroporous consistency is preferred for use in the method according to the invention.
• Such a polymer is equipped with thiourido groups.
• the introduction of the functional group is exemplified in Examples 1 and 2 below.
• the polymers have a usable capacity for thiourido groups of 1-2.2 aeg / l, preferably of 1.3-2.0 aeg / l. They can be used for batch treatment of liquid hydrocarbon mixtures in fine powder form. For use in filtration columns, they are used in an average grain size of 0.2-2 mm, preferably 0.3-1.3 mm. Use in a filtration column for the continuous implementation of the process according to the invention is preferred.
• Apparatus known to the person skilled in the art can be used for the continuous implementation in filtration columns.
• the polymer arranged in the filtration column can be flowed through from top to bottom or from bottom to top; the procedure in which the polymer is blown from below with the hydrocarbon mixture is preferred.
• the polymer containing thiouridino groups can be regenerated with sodium sulfide and then re-used in the process be set.
• at least 2 columns with this polymer are used, at least one of which is in operation for the treatment of hydrocarbon mixtures according to the invention, while at least one other is being regenerated.
• the 1st column is driven until it is completely exhausted and then switched over to regeneration.
• the 2nd column serves as a slip filter and is switched in its place after the 1st column has been exhausted.
• the 3rd column is in regeneration, is then on standby and is activated as a slip filter when switching over.
• the treatment of the hydrocarbon mixtures is carried out at a temperature of from -20 ° C. to + 70 ° C., preferably at 10 to 40 ° C.
• the pressure is not critical for the treatment according to the invention and only serves to keep the hydrocarbon mixture to be treated essentially in the liquid phase. This is done, for example, at a pressure of 1-25 bar.
• the polymer containing thiouridino groups is blown by the hydrocarbon mixture to be treated at an LHSV (Liquid Hourly Space Velocity) of 1-10 l hydrocarbon mixture per liter of polymer containing thiouridino groups per hour.
• LHSV Liquid Hourly Space Velocity
• a weakly basic, primary amino group-containing, macroporous anion exchanger based on styrene-divinylbenzene with a 5% crosslinking and an acid-binding capacity of 1.62 eq / l served as the starting polymer.
• the resin thus produced contained 1.0 mol / l thiourido groups. Sulfur content in the dry matter 8.25%.
• the polymer was a styrene-divinyl resin containing thioureido groups with a usable capacity of 1.8 eq / l (Lewatit TP 214 commercial product from Bayer AG).
• Less than 1 ppb mercury and 6 ppb arsenic were found in the hydrocarbon mixture being discharged.
• the mercury contents of the feed mixture and the process were determined using the AAS cold steam technique.

Landscapes

• 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)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Treatment Of Liquids With Adsorbents In General (AREA)

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Citations (4)

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• 1989
  • 1989-10-12 DE DE19893934101 patent/DE3934101A1/de not_active Withdrawn
• 1990
  • 1990-10-02 EP EP90118844A patent/EP0422480A1/fr not_active Withdrawn

Patent Citations (4)

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