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
  • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
  • C10G9/14—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
  • C10G9/16—Preventing or removing incrustation
• • 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
  • C10G7/00—Distillation of hydrocarbon oils
• • 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
  • C10G75/00—Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils, in general
  • C10G75/04—Inhibiting corrosion or fouling in apparatus for treatment or conversion of hydrocarbon oils, in general by addition of antifouling agents

Definitions

• the present invention relates to a novel antifoulant for petrochemical processes. More particularly, it relates to an antifoulant for petrochemical processes which can effectively prevent formation of fouling in processes in a petrochemical plant, such as the rectification process in an ethylene plant.
• distillation of a fluid containing olefins, such as ethylene and propylene, and diolefins, such as butadiene has been conducted.
• olefins such as ethylene and propylene
• diolefins such as butadiene
• the fluid is modified with heat to form sludge by heating, for example, in a preliminary heat exchanger or a reboiler and the sludge thus formed is adhered to the surface of heat transfer in the preliminary heat exchanger or the reboiler or to the surface of pipings to form fouling.
• antioxidants such as phenolic antioxidants and amine antioxidants
• polymerization inhibitors such as oxime inhibitors and nitroso inhibitors
• dispersants to prevent formation of sludge and adherence of deposit and agents in combinations of these agents
• antifoulants for the purpose of preventing fouling described above.
• an antifoulant comprising a combination of aniline and t-butylcatechol
• an antifoulant comprising nitrosophenol
• the present invention accordingly has an object to provide an antifoulant for petrochemical processes which can eliminate the drawbacks of the conventional antifoulants for petrochemical processes, can be handled easily, is inexpensive, has no adverse effect on the process, shows excellent effect to prevent the formation of fouling, and enables continuous operation of a plant for a long time with good stability.
• the present inventors conducted extensive studies to develop an antifoulant for petrochemical processes having the advantageous properties described above. As the result of the studies, it was discovered that the object can be achieved by an antifoulant comprising a hydrogen-donating hydroaromatic compound.
• the present invention is completed on the basis of the discovery.
• the present invention provides an antifoulant for petrochemical processes comprising a hydrogen-donating hydroaromatic compound.
• the present invention also provides a process for preventing formation of fouling in a petrochemical plant comprising adding the antifoulant for petrochemical processes described above to a process fluid supplied to petrochemical processes in which fouling is formed.
• the hydrogen-donating hydroaromatic compound used as the antifoulant of the present invention has the function of stopping the chain reactions by donating proton to the radical generated in the oxidation and effectively preventing the formation of fouling.
• the hydrogen-donating hydroaromatic compound include tetralin, 9,10-dihydrophenanthrene, 1,2,3,4,5,6,7,8-octahydro-phenanthrene, and hydrogenated terphenyl.
• the compound may be used singly or as a combination of two or more compounds.
• conventional antifoulants such as antioxidants like amine antioxidants and phenol antioxidants, polymerization inhibitors like oxime inhibitors and nitroso inhibitors, metal deactivating agents, and various kinds of dispersant, may be used in addition to the hydroaromatic hydrocarbon according to desire.
• the dispersant disperses organic sludge and inorganic sludge into the process fluid and prevents adherence of deposit to the surface of heat transfer or the surface of pipings. Examples of the dispersant include:
• Examples of the polyalkyl (meth)acrylate used in the dispersant (1) described above include homopolymer of an alkyl (meth)acrylate in which the alkyl group has 5 to 18 carbon atoms, copolymers obtained by copolymerization of two or more kinds of said alkyl (meth)acrylate, and copolymers obtained by copolymerization of one or more kinds of said alkyl (meth)acrylate with one or more kinds of unsaturated monomer having an ethylenically unsaturated bond, such as N-vinyl-2-pyrrolidone and diethylaminoethyl (meth)acrylate.
• Amounts of the components used according to desire in the antifoulant, such as the antioxidant, the polymerization inhibitor, the metal deactivating agent, and the dispersant, are not particularly limited but suitably selected.
• the process fluid to which the antifoulant of the present invention is applied is not particularly limited.
• the antifoulant of the present invention can be applied to any kind of oil for treatment in which fouling is formed in treatments in petrochemical processes. It is preferably applied to process oils treated in a preliminary heat exchanger or a reboiler in a distillation tower, such as a depropanizer, a de-ethanizer, a debutanizer, or a condensate stripper, in an ethylene plant.
• the hydrogen-donating hydroaromatic compound and other components, such as other antifoulants and additional components, which are used additionally according to necessity are dissolved in a suitable solvent to prepare a solution having a concentration of about 0.5 to 60 % by weight.
• the solution thus prepared is added continuously to an apparatus in which fouling is formed in the petrochemical process, such as a heat exchanger, a reboiler or pipings or added to the tank of a material oil in all the amount at one time.
• the amount of the antifoulant of the present invention added to the process fluid is selected generally in the range of 0.5 to 50000 mg/liter, preferably 30 to 200 mg/liter, based on the amount of the process fluid.
• the antifoulant of the present invention has the excellent property to prevent the formation of fouling, continuous operation for a long time, such as for two to three years, is made possible with good stability, in contrast to continuous operation generally practiced for only 3 months when a conventional antifoulant is used. As the result, energy saving and reduction of maintenance cost can be expected and, furthermore, risk accompanied with emergency stopping of the plant can be avoided.
• the antifoulant for petrochemical processes can be handled easily, is inexpensive, has no adverse effect on the process, shows excellent effect to prevent formation of fouling, enables continuous operation of a plant for a long time with good stability and brings energy saving and reduction of maintenance cost.
• Agents of the kinds and the amounts shown in Table 1 were added to a depropanizer bottom fluid taken from a plant in operation.
• the mixture was charged to a 200 milliliter autoclave made of SUS 304 and treated with heat at 100°C for 20 hours. Then, the treated fluid is distilled under a reduced pressure and dried to obtain amount of the residue of evaporation (amount of formed polymer). Rate of suppression of the formation of fouling was calculated for evaluation of the anti-fouling property as the ratio of the value obtained above to the corresponding value obtained in the absence of the agent. Results are shown in Table 1.
• the dispersant is a copolymer of styrene and a maleic acid ester having a molecular weight of 15000 and TBC indicates t-butylcatechol.
• Table 1 agent amount of formed polymer (% by wt.
• Comparative Example 4 aniline 10 0.064 80 TBC 10 dispersant 20 (Note) Amount of the formation of fouling when no agent was added was 0.320 % by weight based on the total amount of the fluid.
• Comparative Examples 1 and 2 showed good results on the rate of suppression of the formation of fouling. However, p-nitro-o-cresol cannot be used practically because of the problem on handling.

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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)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

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• 1993
  • 1993-07-01 JP JP5189249A patent/JPH0718265A/ja active Pending
• 1994
  • 1994-06-28 DE DE69423140T patent/DE69423140T2/de not_active Expired - Fee Related
  • 1994-06-28 EP EP94109954A patent/EP0632121B1/de not_active Expired - Lifetime
  • 1994-06-30 BR BR9402609A patent/BR9402609A/pt not_active Application Discontinuation
  • 1994-06-30 KR KR1019940015379A patent/KR0140052B1/ko not_active IP Right Cessation
  • 1994-07-01 CN CN94107845A patent/CN1110534C/zh not_active Expired - Fee Related

Patent Citations (4)

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