Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/10—Liquid carbonaceous fuels containing additives
  • C10L1/14—Organic compounds
  • C10L1/18—Organic compounds containing oxygen
  • C10L1/188—Carboxylic acids; metal salts thereof
  • C10L1/1881—Carboxylic acids; metal salts thereof carboxylic group attached to an aliphatic carbon atom

Definitions

• This invention pertains to a method for reducing the corrosiveness of ash produced by the combustion of residual type hydrocarbon fuels. It further pertains to improved residual fuel compositions which form substantially non-corrosive ash when they are burned.
• the invention is more particularly concerned with a composition comprising calcium, barium or magnesium complex salts wherein these salts are present in a stable suspensable form in the residual fuel.
• These fuels may be the residual products or blends thereof, obtained from refining operations such as the distillation of crudes, the flashing or distillation of cracked products and redistilla tion operations. They may consist of either virgin or cracked hydrocarbons.
• the viscosity of a residual fuel is one of its more important properties, it is sometimes necessary, where a particular residuum is too viscous, to dilute it with a low viscosity distillate fraction. It is thus apparent that residual fuels may contain distillate fractions as well as residues but in general they consist primarily of residual material.
• Residual fuel oils are also known in the trade as bunker fuel oils. They are characterized roughly as boiling above 400 F.
• the United States Department of Commerce recognizes two grades of residual fuel (No. 5 and No. 6) in its classification system for petroleum fuels.
• the No. 5 grade is essentially a distillate fuel with small amounts of residual materials. t contains relatively little ashforming material.
• the No. 6 fuel is usually a true residual fuel containing a substantial amount of ash, as for example, up to 0.10% by weight or more. It is this grade with which this invention is primarily concerned.
• the No. 6 or bunker fuel grade has a gravity range of about 9 to 15 A. P. 1., a viscosity range of about 30 to 300 at 122 F. (Saybolt Furol), a minimum flash point of 150 F. and a Conradson carbon residue of at least 0.5%.
• This invention is concerned primarily with the ash present in residual or bunker fuel oils.
• the amount and type of ash formed by a residual fuel oil during combustion vary primarily with the ash content and the origin of the crude oil from which it was derived. Crude oils when burned may form up to about 3% by weight of ash and the ash-forming constituents are concentrated almost entirely in the residue by refining operations performed on the crudes. Residual fuels, as such, however, generally contain less than 0.10% by weight of ash.
• the vanadium content of ash derived from domestic crude oils will vary in general from about 0 to 20% V 0 Residual fuel oils obtained from Middle East crudes produce ash with vanadium contents of 14 to 45%, while in the case of South American crudes, the value may be as high as At the present time it is not known exactly what chemical forms or compounds of vanadium actually exist in these oils.
• the amount of ash in a residual fuel oil, and in particular, its vanadium content has recently become a matter of great importance. This is particularly true in the power generation field where the vanadium contained in the fuels employed has been found to cause extensive corrosion in power equipment that operates at high temperatures. Examples of such high temperature equipment include the gas turbine, the mercury boiler and extremely high temperature and pressure steam boilers. All of these installations have metal parts which are exposed at temperatures above 1000 F. directly to the gases produced by the combustion of residual fuel. In the case of the boilers, the metallic parts include such items as the boiler tubes and super heater tubes.
• the burner chamber, turbine nozzles, and blading are among the parts subjected to these conditions. In general, extensive corrosion of all of these parts has occurred, particularly when a residual fuel forming an ash of high vanadium content was employed.
• vanadium oxides e. g. V 0 and vanadates.
• vanadium pentoxide has a melting point of 1274 F.
• this material very often is present in its liquid form and has a substantial vapor pressure at the temperatures existing in gas turbine or boiler installations.
• Experimental Work shows that vanadium pentoxide is extremely corrosive toward even the most corrosionresistant alloy steels at temperatures of 1200 F. and up. It has further been shown that this chemical compound is most corrosive when it is present as a fluid. It appears that vanadium pentoxide or other vanadic acids not only oxidation catalyst, thereby markedly increasing the rate of corrosion once it has started.
• an object ofthe present invention is to provide vanadium-containing residual fuel oil compositions which when burned will form ash'that is substantially non-corrosive toward steel and steel alloys at tem peratures of 1000 F. and higher. It is a particular object to provide vanadium-containing, residual'fuel oil compositions which when burned in installations such as gas turbines, mercury boilers, high-pressure steam boilers, etc.. are virtually non-corrosive toward the ferruginous alloys used therein.
• the present invention avoids these difi'iculties by utilizing a complex soap of a low molecular weight monobasic carboxylic acid and a high molecular weight monobasic carboxylic acid.
• Desirable low molecular weight acids are acetic acid or other COOH acids having from 1 to 5 carbon atoms, as for example, formic, propionic, crotonic, acrylic, and the like. Satisfactory high molecular weight acids are preferably those of C to C chain length; for
• stearic acid examples include stearic acid, oleic acid, hydrogenated fish oil acids, and other acids of the types used in the manufacture of greases.
• oleic acid examples include stearic acid, oleic acid, hydrogenated fish oil acids, and other acids of the types used in the manufacture of greases.
• hydrogenated fish oil acids examples include stearic acid, oleic acid, hydrogenated fish oil acids, and other acids of the types used in the manufacture of greases.
• the weight percentage of the low molecular weight acid in the complex soap should be in the range from to 80% by weight, preferably in the range from 50% to 80% by weight, while the percentage of the high molecular weight acid should be in the range from 90% to 20%, preferably in the range from 50% to 20% by weight.
• these ranges correspond to mol ratios of low to high molecular weight acids of 0.5/1 to 1. Mol ratios higher than 5/ 1, preferably 7/1 or higher, are definitely preferred, since these are used in lower concentrations in the fuel and have less effect on flame pattern.
• These complex soaps are formed at elevated temperatures. They are also preferably formed in the presence of a mineral oil, as for example, one having a gravity in the range from about 19 to 22 API. Actually, the residual fuel, if high enough flash, can be employed as the soap diluent in the concentrate.
• Example I A typical satisfactory composition for use in accordance with the present invention is as follows:
• the method of preparation is to mix the hydrogenated fish oil acids and /5 volume of the mineral oil diluent.
• the temperature of the mixture is raised to about 150 F, and the acetic acid added.
• a slurry of hydrated lime in the balance of the mineral oil is added to the mixture.
• the temperature is then raised to about 250 to 300 F., and the water driven off. 7
• the temperature is then raised to 450 or 500 5., where the mass becomes solid and the complex forms.
• the data show the calcium to be well distributed and suspended in the fuel. Also, the amount of calcium in the fuel is in good agreement with the amount added
• the invention is broadly concerned with the preparation of stable dispersions of high metal content soaps in residual fuels with no tendency toward settling out, even under severe conditions. This is secured by placing the metal in the fuel as a complex metal soap. While one method of preparation has been disclosed, it is within the scope of the present invention to include these complex soaps by any manner of manufacture whatsoever.
• the process is intended to cover the addition of the above components, high molecular weight acid, low molecular Weight acid and hydrated lime directly to the fuel or to its components in its processing or while in storage at temperatures between about 250 to 550 F. Acids such as acetic acid, formic acid and the like, in combination with fatty acids such as palmitic, oleic, stearic and the like are contemplated.
• the amount of metal added to the fuel as the complex soap is usually from about 0.02 to about 0.5 wt. percent. In the case of calcium, from 0.04 to 0.2 wt. percent will generally be su'tlicient to suppress corrosion by most residual fuels. Corrosion by vanadium is particularly suppressed when the atomic ratio of added metal to vanadium is in the range from l/l to 5/1, preferably 2/1 to 3/1. Although the invention is especially useful as regards vanadium-induced corrosion, it can be applied to fuels of relatively low vanadium content in order to secure other advantages such as a reduction in stock solids.
• An improved residual hydrocarbon fuel containing vanadium as an impurity said fuel having dissolved therein from about 0.02% to about 0.5% by weight of a metal selected from the group consisting of calcium, barium, and magnesium, said metal being in the form of a complex soap obtained by the saponification of a low molecular weight monobasic carboxylic acid containing from 1 to 5 carbon atoms and a high molecular weight monobasic carboxylic acid containing from 16 to 22 carbon atoms, said complex soap consisting of from about 10 to 80% by weight of the soap of said low molecular weight acid and from about to 20% by weight of the soap of the said high molecular weight acid.
• sutficient complex soap is present to secure an atomic ratio of said metal selected from the group consisting of calcium, barium and magnesium to vanadium of from about 1:1 to 5:1.
• composition of claim 1 wherein said metal is calcium.
• composition of claim 1 wherein said metal is barium.
• composition of claim 1 wherein said metal is magnesium.
• composition of claim 1 wherein said low molecular weight monobasic carboxylic acid is acetic acid and said high molecular weight monobasic carboxylic acid is stearic acid.
• composition according to claim 1 wherein said complex soap is obtained by the saponification of a mixture of glacial acetic acid and hydrogenated fish oil acids with hydrated lime.
• composition of claim 1 wherein said complex 15 soap consists of from about 50 to 80% by weight of the soap of said low molecular weight acid and from about 50 to 20% by weight of the soap of said high molecular weight acid.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Priority Applications (5)

Applications Claiming Priority (1)

Publications (1)

Family

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Cited By (4)

Citations (5)

• 0
  • NL NL97187D patent/NL97187C/xx active
• 1953
  • 1953-10-21 US US387528A patent/US2832677A/en not_active Expired - Lifetime
• 1954
  • 1954-07-13 CH CH330829D patent/CH330829A/de unknown
  • 1954-08-14 DE DEST8615A patent/DE1045025B/de active Pending

Patent Citations (5)

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