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

Definitions

• the processes involved in oil, gas and petrochemical refining for example, reforming, hydroforming, absorption, hydrocracking, isomerization, extraction, cracking, fractionation, hydrofining, desalting and the like, expose hydrocarbon streams to relatively elevated temperatures. These temperatures are most commonly attained by the use of heaters and heat exchangers in which the hydrocarbon feeds, products and intermediates are intimately contacted with heated surfaces. These conditions are known to promote the formation of fouling deposits which can drastically limit refining capacities and flow rates.
• the fouling deposits which are encountered as a result of the physical and/or chemical modification of hydrocarbon feeds initiated by elevated process temperatures may consist of sticky, tarry, polymeric or carbonaceous material.
• the most common fouling deposits can be generally classified as inorganic salts, corrosion products, metal-organic compounds, organic polymers and coke.
• the inorganic salts such as sodium, calcium and magnesium chloride are probably carried into the process system with the crude feed stock.
• Metal-organic compounds may also be present in the feed stock or may be formed on heat transfer surfaces by combination with corrosion products or other metals carried into the system.
• the formation of organic polymers is most commonly attributed to reaction of unsaturated hydrocarbons. Coke deposition is usually associated with the occurrence of hot spots caused by the accumulation of fouling deposits. Consequently, it can be shown that, in such processes, the metal and organic elements of fouling deposits interact with each other.
• This invention relates to novel antifoulant compositions and to the use thereof to inhibit fouling of equipment used in the refining of crude oil, gas and petrochemicals and in the thermal processing of other organic materials.
• the invention relates to the use of colloidally dispersed overbase complex antifoulants in oil refineries, gas plants and petrochemical refineries. More particularly, the invention relates to overbase complexes of magnesium oxides and magnesium carbonates with at least one complexing agent and to their use as antifoulants in oil, petrochemical and gas refining operations.
• antifoulants A wide variety of antifoulants has been used in attempts to inhibit fouling associated with the decomposition of crude and refined oils, gases and petrochemical feed streams.
• a partial, but representative, listing of patents relating to antifoulant compositions and their uses is set forth below.
• UK Patent Appln. 2017747 A describes sodium di-2-ethylhexylsulphosuccinates as fouling inhibitors for crude petroleum oil and UK Patent 2021144 B describes polyalkylenoxy sulfoxy salts for preventing and removing fouling deposits on refining equipment for hydrocarbon feed streams.
• Overbased oil-stable, fluid dispersions or “solutions” of complexes containing, e.g., magnesium and calcium, and their preparation and use are well known to those skilled in the art.
• base historically refers to metal base/acid reaction products containing an amount of metal in stoichiometric excess of that required to form a neutral organic acid salt of such base. Synonomous terms frequently used include “basic”, “highly basic” and “hyperbased”.
• U. S. 2,585,520 discloses the preparation of high ly basic magnesium and calcium petroleum sulfonates useful as additives for lubricating oils.
• U. S. 2,895,913 discloses the preparation of stable oil-dispersible over-based organo-magnesium compounds useful as additives in lubricating oils.
• U. S. 3,057,896 discloses the preparation of overbased calcium sulfonates useful as additives for lubricating oils.
• U. S. 3,150,089 discloses stable dispersions of overbased organo-magnesium compounds useful as additives for lubricating oils.
• U. S. 3,629,109 discloses the preparation of overbased organo-magnesium complexes which are useful as lubricant and fuel additives.
• U. S. 3,764,536 discloses the preparation of an overbased calcium salt of alkenlsuccinimide which is useful as a dispersant additive for lubricating oils.
• U. S. 3,776,835 discloses detergent-dispersant compositions used as antifoulants in fouling caused by high temperature hydrocarbon streams.
• Such compositions include sulfonates, especially normal and basic metal salts of benzene sulfonic acids, normal and basic salts of phosphonic and thiophosphonic acids, the normal and basic salts of phenates and carboxylate and carboxylate-phenate salts, alkenyl succinimides, alkali metal naphthenates and amines and carboxylic acids.
• U. S. 3,865,737 discloses the preparation of fluid, overbased organomagnesium complex dispersion which is useful as a lubricating composition additive.
• U. S. 4,163,728 discloses the preparation of a stable, fluid organomagnesium complex dispersion useful as an acidic neutralization additive for lubricating oils.
• the compounds disclosed are overbased.
• U. S. 4,293,429 discloses the preparation of an overbased mixture of a magnesium carboxylate and magnesium oxide in the form of a fluid dispersion of submicron-sized magnesium oxide.
• the compounds are useful as additives for lubricants.
• U. S. 4,295,981 discloses the preparation of overbased magnesium phenates useful as lubricating oil additives.
• U.S. 4,298,482 describes the preparation of an overbased mixture of magnesium salts and magnesium hydroxide in the form of a dispersion of very small particles.
• the overbased material is useful as an acid neutralizer for lubricating oils and fuels.
• U.S. 4,347,147 discloses the preparation of magnesium sulfonates and magnesium oxide having a small particle size.
• U. S. 4,474,710 discloses the preparation of overbased mixtures of magnesium hydroxide or magnesium carbonate in a liquid magnesium sulfonate dispersant.
• the materials are useful as lubricant additives.
• the present invention pertains to novel antifoulant compositions which are mixed overbase complexes comprising oil-stable colloidal dispersions of fine particles of magnesium oxide and magnesium carbonate and complexing agents and their use in the inhibition of fouling, particularly high temperature fouling, e.g., 500-1200°F., in refining processes.
• a fouling problem in one area of a refinery may not necessarily respond to the same antifoulant treatment as does a different area of a refinery. Accordingly, treatment of refining operations must be broken down, unit by unit, and the particular fouling characteristics of each unit must be defined and treated appropriately.
• an oxide and carbonate of magnesium is prepared in conjunction with organic acid complexing agents, a product results which is an overbase complex of Mg oxide and Mg carbonate, in extremely fine, preferably submicron particle size, and the magnesium metal salt of the complexing agents. It is theorized that the presence of the complexing agent, during preparation of the metal oxide and carbonate, protects the fine particles of metal oxide or carbonate from agglomerating and allows the fine particles to remain dispersed in a stable manner in the diluent used in th e reaction and, later, in a hydrocarbon stream.
• overbase comprises dispersions of salts formed by contacting an acidic material with a basically reacting metal compound, e.g., a metal hydroxide. Alternatively, it has been suggested that they comprise "polymeric salts". It is believed that neither theory is incorrect but that neither is completely correct. In accordance with the present invention, it is believed that the preparation of an "overbased” material results in an "overbase complex" of a metal oxide or carbonate with an organic acid dispersant or stabilizer (i.e., "complexing agent"). The nature of the complex so-formed is not completely understood.
• an "overbase complex” is a complex of an oxide or carbonate of magnesium and a magnesium salt of an organic acid "complexing agent".
• the overbase complex contains a stoichiometric excess of metal, relative to the number of equivalents of acid complexing agent which is reacted with a basic metal compound to afford the complex, based on the normal stoiochiometry of the particular metal base and acid.
• a "neutral” or "normal” metal salt of an acid is characterized by an equivalent ratio of metal to acid of 1:1, while an overbased salt is characterized by a higher ratio, e.g., 1.1:1, 2:1, 5:1, 10:1, 15:1, 20:1, 30:1 and the like.
• metal ratio is used to designate the ratio of (a) equivalents of metal to acid in an overbased salt to (b) the number of equivalents expected to be present in a normal salt, based on the usual stoichiometry of the metal or metals involved and the acid or acids present.
• metal ratio 10 (i.e., 20 ⁇ (1+1)).
• magnesium for example, is regarded as having two equivalents per atomic weight; magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)2), two equivalents per mole.
• Organic acids are regarded as having one equivalent of acid per acidic hydrogen or acid group.
• a monocarboxylic acid or monosulfonic acid or their equivalent derivatives such as esters and ammonium and metal salts, have one equivalent per mole of acid, ester or salt; a disulfonic acid or dicarboxylic acid, or equivalent derivative, has two equivalents per mole.
• the basically reacting metal compounds such as the oxides and carbonates of magnesium have two equivalents per mole (i.e., two equivalents per atomic weight of metal).
• the complex antifoulants of the invention are overbase complexes of magnesium oxides and magnesium carbonates and magnesium salts of organic acid complexing agents.
• the mixed overbase complexes used in the present invention may be prepared in any manner known to the prior art for preparing overbased salts, provided that the overbase complex resulting therefrom is in the form of finally divided, preferably submicron, particles capable of forming a stable dispersion in oil.
• a preferred method for preparing the magnesium oxide/complexing agent overbase complex of the present invention is to form a mixture of a magnesium base, e.g., Mg(OH)2, a complexing agent, e.g., a fatty acid such as a tall oil fatty acid, which is present in a quantity much less than that required to stoichiometrically react with the hydroxide, and a non-volatile diluent.
• the mixture is heated to a temperature ofabout 250-350°C. whereby there is afforded the overbase complex of magnesium oxide associated with the Mg salt of the complexing agent.
• the magnesium carbonate/complexing agent overbase complex is prepared in the same manner as described above, except that carbon dioxide is bubbled through the initial reaction mixture.
• Complexing agents which are used in the present invention are fatty acids, e.g., tall oil fatty acids, and sulfonic acids.
• the sulfonic acids which are oil-soluble per se are especially useful. Oil-soluble derivatives of these acids, such as their metal salts, ammonium salts, and esters (particularly esters with lower aliphatic alcohols having up to six carbon atoms, such as the lower alkanols), can be utilized in lieu of or in combination with the free acids.
• the acid its equivalent derivatives are implicitly included unless it is clear that only the acid is intended.
• T is a cyclic nucleus of the mono- or polynuclear type including benzenoid, cycloaliphatic or heterocyclic neuclei such as a benzene, naphthalene, anthracene, 1,2,3,4-tetrahydronaphthalene, thianthrene, cyclopentene, pyridine or biphenylnucleus and the like.
• T will represent an aromatic hydrocarbon nucleus, especially a benzene or naphthalene nucleus.
• variable R in the radical R x can be, for example, an aliphatic group such as alkyl, alkenyl, alkoxy, alkoxyalkyl, carboalkoxyalkyl, an aralkyl group, or other hydrocarbon or essentially hydrocarbon groups, while x is at least 1 with the proviso that the variables represented by the group R x are such that the acids are oil-soluble.
• the groups represented by R x should contain at least about eight aliphatic carbon atoms and preferably at least about twelve aliphatic carbon atoms.
• x will be an integer of 1-3.
• the variables r and y have an average value of one to about four per molecule.
• variable R ⁇ in Formula II is an aliphatic or aliphatic-substituted cycloaliphatic hydrocarbon or essentially hydrocarbon radical.
• R ⁇ is an aliphatic radical, it should contain at least about 8 to about 20 carbon atoms and where R ⁇ is an aliphatic substituted-cycloaliphatic group, the aliphatic substituents should contain about 4 to 16 carbon atoms.
• R ⁇ are alkyl, alkenyl, and alioxyalkyl radicals and aliphatic-substituted cycloaliphatic radicals wherein the aliphatic substituents are alkoxy, alkoxyalkyl, carboalkoxyalkyl, etc.
• the cycloaliphatic radical will be a cycloalkane nucleus or a cycloalkene nucleus such as cyclopentane, cyclohexane, cyclohexene, cyclopentene, and the like.
• R ⁇ are cetyl-cyclohexyl, laurylcyclohexyl, cetyloxyethyl and octadecenyl radicals, and radicals derived from petroleum, saturated and unsaturated paraffin wax, and polyolefins, including polymerized mono- and diolefins containing from about 1 to 8 carbon atoms per olefin monomer unit.
• the groups T, R and R ⁇ in Formulae I and II can also contain other substituents such as hydroxy, mercapto, halogen, nitro, amino, nitroso, carboxy, lower carbalkoxy, etc., as long as the essentially hydrocarbon character of the groups is not destroyed.
• the sulfonic acids which are preferred for use herein include alkyl sulfonic acids, alkaryl sulfonic acids, dialkyl sulfonic acids, dialkylaryl sulfonic acids, aryl sulfonic acids, e.g., ethylsulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid and more complex sulfonic acid mixtures such as mahogany sulfonic acids and petroleum sulfonic acids.
• illustrative examples of the sulfonic acids are mahogany sulfonic acids, petrolatum sulfonic acids, mono- and poly-wax-substituted naphthalene sulfonic acids, cetylchlorobenzenesulfonic acids, cetylphenol sulfonic acids, cetylphenol disulfide sulfonic acids, cetoxycaprylbenzene sulfonic acids, dicetyl thianthrene sulfonic acids, di-lauryl beta-naphthol sulfonic acids, dicapryl nitronaphthylene sulfonic acids, paraffin wax sulfonic acids, unsaturated paraffin wax sulfonic acids, hydroxy-substituted paraffin wax sulfonic acids, tetraisobutylene sulfonic acids, tetraamylene sulfonic acids, chloro-substituted paraffin
• the antifoulants of the present invention are a mixture of (A) an overbase complex of fine particle size magnesium oxide and the magnesium salt of a fatty acid and (B) an overbase complex of fine particle size magnesium carbonate and the magnesium salt of a sulfonic acid or mixture of sulfonic acids.
• the overbase complex of magnesium oxide and the magnesium salt of a tall oil fatty acid may be prepared in accordance with the method described in U. S. 4,163,728.
• the overbase complex of magnesium carbonate and the magnesium salt of a sulfonic acid may be similarly prepared by introducing CO2 during the reaction of Mg(OH)2 with a sulfonic acid.
• an overbase complex of magnesium carbonate and the magnesium salt of sulfonic acids is available commercially as Witco M400.
• the weight ratio of one overbase complex to the other is from about 0.25/10 to about 10/0.25.
• the de-ethanizer reboilers were cleaned but fouling progressively increased. After six months, production was stopped. The plant was cleaned to remove the buildup of foulant in reboilers and the de-ethanizer tower. Foulant blocking in the de-ethanizer tower was more than four feet thick. A 16" diameter pipework was reduced to a 2" diameter flow area.
• the foulants removed from the reboilers varied in texture from soft putty to crystalline anthracite coal.
• an antifoulant of the invention was injected into the feed to the de-ethanizer at a rate of 100 ppm based on the weight of the hydrocarbon stream.
• the antifoulant was a mixture of (A) an overbase complex of magnesium oxide and the magnesium salt of a tall oil fatty acid and (B) an overbase complex of magnesium carbonate and the magnesium salt of sulfonic acids (Witco M400) in a weight ratio of about 1/1.
• Fouling monitoring was accomplished by measuring the overall heat transfer of the reboiler. The plant has now operated for 15 months without a fouling problem.
• the reaction of metal base and acid affords a product which undergoes decomposition to afford minute particles of metal oxide or carbonate in association with the metal salt of the acid.
• the minute particle s immediately become suspended and stabilized by the metal salt of the acid.
• the particles of metal oxide or metal carbonate are of a size no greater than about 2 microns in diameter, for example no greater than about 1 micron but, preferably, are no greater than about 0.1 micron and, especially, should be less than 0.1 micron in diameter.
• the amount of antifoulant which is used to inhibit fouling in a fouling area will vary, depending on the environment of the area, the degree of fouling and the specific antifoulant used. In general, an amount of antifoulant is used which is effective to inhibit fouling in an area. Accordingly, there mya be used an amount of from about 5 ppm to about 1000 ppm or more based on the weight of the hydrocarbon stream, depending on specific circumstances. Ordinarily, from about 25 ppm to about 500 ppm are effective, especially from about 50 to about 300 ppm.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Thermal Sciences (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
• Medicines Containing Plant Substances (AREA)

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• 1987
  • 1987-09-04 EP EP19870307864 patent/EP0266872A1/fr not_active Withdrawn
  • 1987-09-04 DE DE1987307864 patent/DE266872T1/de active Pending
  • 1987-09-04 ES ES87307862T patent/ES2008053A4/es active Pending
  • 1987-09-30 CN CN198787106631A patent/CN87106631A/zh active Pending

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