MXPA06010562A - Conversion of petroleum resid to usable oils with ultrasound - Google Patents

Abstract

Petroleum residua are combined with water or an aqueous solution to form an emulsion which is then treated with ultrasound at a sufficient intensity and for a sufficient period of time to cause a conversion of the heavy hydrocarbon components of the residua to lighter components, thereby shifting the entire boiling point curve to lower boiling points. This allows one to draw a greater proportion of usable oil from the residua.

Description

CONVERSION OF OIL RESIDUE TO ULTRASONIC USEFUL OILS FIELD OF THE INVENTION The present invention is concerned with the field of crude oil and crude petroleum fractions and in particular residual petroleum fractions. In particular, the present invention is concerned with reforming processes to derive usable oil from or increase the usable oil that can be extracted from petroleum residues.

BACKGROUND OF THE INVENTION Crude oil is the largest and most widely used natural resource in the world, it serves as a source of a wide range of fuels for the consumer and industrial use, as well as chemical compounds for use as raw materials in products used every day in the whole world. Petroleum residues (or "residues") are the heavy fraction remaining after oil crudes are distilled at atmospheric pressure or reduced pressure, that is, the waste left after most easily accessible components of the oil are extracted. The residues are highly complex in composition, including components of such molecular weight, as well as polynuclear aromatics, coke, asphaltenes, resins, small ring and saturated aromatics. Unfortunately, waste is extremely limited in utility. A variety of conversion processes have been developed to increase the utility of or obtain useful waste products. These processes include separations, thermal conversion, hydroconversion or hydrotreatment and fluid catalytic cracking. However, processes that are more economical result in a carbonaceous byproduct that is even heavier than the starting residue, including the additional formation of polynuclear aromatics. Processes involving the use of catalysts are also expensive due to the cost of the catalysts themselves and the expense of recovering and recycling the catalysts after use. Also, the oil industry is continually looking for ways to use lower quality waste and lower cost due to the continued need for new crude oil resources and the continuing pressure from the public and regulatory agencies to make use of this waste instead of discard them. As a result, processes that can economically and effectively convert these wastes to lighter components are continually needed.

BRIEF DESCRIPTION OF THE INVENTION It has now been discovered that fossil fuels, crude oil fractions and particularly petroleum residues can be converted to lower melting point mixtures by a process that applies ultrasound to these materials in an aqueous emulsion. The entire boiling point distribution of a waste, which fluctuates from 93 ° C to more than 540 ° C (200 ° F - 1,000 ° F) can be displaced at lower temperatures. Components with boiling points in the range of approximately 200 ° C to approximately 430 ° C (400 ° F -800 ° F), for example, may have their boiling points decreased by a minimum of 11 ° C (20 ° F). ) through this process. The process results in an improvement of the starting material by increasing the amount of usable oil and other products that can be extracted from the starting material and by increasing API gravity and decreasing the viscosity of the material. These and other objects, advantages aspects and embodiments of the invention will become apparent from the description that follows.

BRIEF DESCRIPTION OF THE FIGURE Figure 1 is a graph, derived by high temperature simulated distillation, of cumulative volume distilled against true boiling point, for a sample of untreated crude oil and for samples treated in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION AND SPECIFIC MODALITIES The present invention is applicable to any residual carbonaceous liquid that is derived from petroleum., coal or any other material that occurs in a stable manner in nature. Residue of petroleum and waste-based fuel oils, which include fuels from fuel tanks and residual fuels, are of particular interest. Fuel oil No. 6, for example, which is also known as "C fuel tank" fuel oil, is used in oil-fueled power plants as the main fuel and is also used as the main propulsion fuel in ships of Deep draft in the packaging industry. Fuel oil No. 4 and fuel oil No. 5 are used to heat large buildings such as schools, apartment buildings and office buildings and large stationary marine engines. The heaviest fractions are the residues, which include the fractional distillation vacuum residue, commonly referred to as "vacuum residue", with a boiling point of 565 ° C and higher, which is used as asphalt and coker feed. The present invention is useful in the treatment of any of these oils or fractions for purposes of increasing the proportion of usable oils and other petroleum products that can be extracted from them. The waste, as indicated above, is of particular interest. The properties of residues and other petroleum-derived oils that have been treated by ultrasound in accordance with this invention are significantly improved in relation to the same materials before treatment. Included among these improved properties are boiling point and API gravity. The term "API gravity" is used in the present as it is among those experienced in the art of petroleum fuels and petroleum-based fuels. In general, the term represents a scale of measurement adopted by the American Petroleum Institute, the values in the scale increase as the values of specific gravity decrease. The application of ultrasound in the practice of this invention is carried out in an emulsion of the oil in an aqueous fluid. The aqueous fluid may be water or any aqueous solution. The relative amounts of organic and aqueous phases may vary and while the proportion may affect the efficiency of the process or the ease of handling of fluids, the relative amounts are not critical to this invention. In most cases, however, better results will be obtained when the volumetric ratio of organic phase to aqueous phase is from about 8: 1 to about 1: 5, preferably from about 5: 1 to about 1: 1 and more. preferably from about 3: 1 to about 1: 1. A hydroperoxide may be included in the emulsion as an optional additive, but it is not critical to the success of the conversion when a hydroperoxide is present, the amount may vary. In most cases, better results will be obtained when a hydroperoxide concentration of from about 10 ppm to about 100 ppm by weight and preferably from about 15 ppm to about 50 ppm by weight of the aqueous solution, particularly when the hydroperoxide is H202 . Alternatively, when the amount of H202 is calculated as a component of the combined organic and aqueous phases, better results will generally be obtained in most systems with a concentration of H202 in the range of about 0.0003% to about 0.03% by volume ( as H202) and preferably from about 0.001% to about 0.01% of the combined phases. For hydroperoxides other than H202, the preferred concentrations will be those of equivalent molar amounts. In certain embodiments of this invention, a surfactant or other emulsion stabilizer is included to stabilize the emulsion as the organic and aqueous phases are prepared for ultrasound exposure. Certain fractions of petroleum contain surfactants as components that are stably present in the nature of the fractions and these agents can serve by themselves to stabilize the emulsion. In other cases, synthetic surfactants or that occur in a stable manner in nature can be added. Any of the wide variety of known materials that are effective as emulsion stabilizers can be used. These materials are listed in various references such as McCutcheon's Volume 1: Emulsifiers &; Detergents - 1991 North American Edition, McCutcheon's Division, MC Publishing Co. , Glen Rock, New Jersey, United States of America and other published literature. Cationic, anionic and nonionic surfactants can be used. Preferred cationic species are quaternary ammonium salts, quaternary phosphonium salts and crown ethers. Examples of quaternary ammonium salts are tetrabutyl ammonium bromide, tetrabutyl ammonium hydrogen sulfate, tributylmethyl ammonium chloride, benzyltrimethyl ammonium chloride, benzyltriethyl ammonium chloride, methyltricaphenyl ammonium chloride, dodecyltrimethyl ammonium bromide, tetraoctyl ammonium bromide, cetyltrimethyl ammonium and trimethyloctadecyl ammonium hydroxide. Quaternary ammonium halides are useful in many systems and most preferred are dodecyltrimethyl ammonium bromide and tetraoctyl ammonium bromide. Surfactants may also be used which will promote the formation of an emulsion between the organic and aqueous phases by passing liquids through a common mixing pump, but which will spontaneously separate the product mixture into aqueous and organic phases when allowed to settle. Once settled, the phases can be separated by decanting or other conventional phase separation procedures. A class of surfactants that will easily form an emulsion and will still easily separate consists of aliphatic hydrocarbons of C 5 -C 20 and mixtures of such hydrocarbons, preferably those having a specific gravity of at least about 0.82 and more preferably at least approximately 0.85. Examples of hydrocarbon mixtures that meet this description and are particularly convenient for use and readily available are mineral oils, preferably heavy or extra heavy mineral oil. The terms "mineral oil", "heavy mineral oil" and "extra heavy mineral oil" are well known in the art and are used herein in the same manner as they are commonly used in the art. Such oils are readily available from commercial chemical suppliers around the world. The amount of mineral oil can vary and the optimum amount will depend on the grade of mineral oil, the composition of the crude oil fraction or residue, the relative amounts of the aqueous and organic phases and the operating conditions. The appropriate selection will be a matter of routine choice and adjustment for the experienced technician. In the case of mineral oil, better and more efficient results will generally be obtained by using a volumetric ratio of mineral oil to organic phase of about 0.00003 to about 0.003.

Another additive that is useful in the formation and stabilization of the emulsion is dialkyl ether. Preferred dialkyl ethers are those having a normal boiling point of at least 25 ° C. Both cyclic and acyclic ethers can be used and thus are represented by the formula R1OR2 in which R1 and R2 are either separate monovalent alkyl groups or are combined in a single divalent alkyl group, either in one case or another saturated or unsaturated but preferably saturated. The term "alkyl" is used herein to refer to both saturated and unsaturated alkyl groups. If R1 and R2 are two separate monovalent groups or a combined divalent group, the total number of carbon atoms in R1 and R2 is from 3 to 7, preferably 3 to 6 and more preferably 4 to 6. In an alternative characterization, the dialkyl ether is one whose molecular weight is about 100. Examples of dialkyl ethers that would be preferred in the practice of this invention are diethyl ether, methyl butyl tertiary ether, methyl-n-propyl ether and methyl isopropyl ether. The most preferred is diethyl ether. When a dialkyl ether is used, its amount may vary. In most cases, however, better results will be obtained with a volumetric ratio of ether to the waste or other material to be treated that is within the range of about 0.00003 to about 0.003 and preferably in the range of about 0.0001 to about 0.001 . The dialkyl ether can be added directly to either the residue or the aqueous phase, but it can also be first diluted in an appropriate solvent to facilitate the addition of the ether to either one phase or another. In a presently preferred method, the ether is first dissolved in kerosene at 1 part by volume of ether to 9 parts by volume of kerosene and the resulting solution is added to the residue before the formation of the emulsion. Another optional component of the system is a metallic catalyst. Examples are transition metal catalysts, preferably metals having atomic numbers from 21 to 29, 39 to 47 and 57 to 79. Particularly preferred metals of this group are nickel, silver, tungsten (and tungstates) and combinations thereof. In certain systems within the scope of this invention, Fenton catalysts (ferrous salts) and metal ion catalysts in general such as iron (II), iron (III), copper (I), copper (II), chromium (III) ions ), chromium (IV), molybdenum, tungsten and vanadium are useful. Of these, the catalysts of iron (II), iron (III), copper (II) and tungsten are preferred. For some systems, Fenton type catalysts are preferred, while for others, tungstates are preferred. Tungstates include tungstic acid, substituted tungstic acids such as phosphotungstic acid and metal tungstates. The metal catalysts, when present, will be used in a catalytically effective amount, which means any amount that will improve the progress of the reactions by which the waste or oil components are improved. The catalyst can be present as metal particles, pellets, meshes or any form having high surface area and can be retained in the ultrasound chamber. A further improvement in efficiency of the invention is often obtainable by pre-heating the waste, the aqueous fluid or both, prior to the formation of the emulsion or by exposing the emulsion to ultrasound. The degree of pre-heating is not critical and can vary widely, the optimum degree depends on the particular starting material and the proportion of aqueous to organic phases. In general, better results will be obtained by pre-heating at a temperature in the range of about 50 ° C to about 100 ° C. For fuels with an API gravity of about 20 to about 30, preheating is preferably carried out at a temperature of about 50 ° C to about 75 ° C, while for fuels with an API gravity of about 8 to about 15, the preheating is preferably carried out at a temperature of about 85 ° C to about 100 ° C. Ultrasound consists of sound-like waves at a frequency above the range of normal human hearing, that is, greater than 20 KHz (20,000 cycles / second). Ultrasonic energy with frequencies as high as 10 gigahertz (10,000,000,000 cycles / second) has been generated, but for the purposes of this invention, useful results will be obtained with frequencies in the range of about 1 MHz to about 100 MHz. Ultrasonic waves can be generated from sources of mechanical, electrical, electromagnetic or thermal energy. The intensity of the sonic energy can also vary widely. For the purposes of this invention, better results will generally be obtained with an intensity ranging from about 30 watts / cm2 to about 300 watts / cm2 or preferably from about 50 watts / cm2 to about 100 watts / cm2. The representative electromagnetic source is a magnetostrictive transducer that converts magnetic energy into ultrasonic energy by applying a strong alternating magnetic field to certain metals, alloys and ferrites. The representative power source is a piezoelectric transducer, which uses individual natural or synthetic crystals (such as quartz) or ceramics (such as barium titanate or lead zirconate) and applies an alternating electrical voltage across appropriate faces of the crystal or ceramic to cause an alternating expansion and contraction of glass or ceramic at the applied frequency. Ultrasound has wide applications in areas such as cleaning for the electronics, automotive, aircraft industries of precision instrument industries, flow measurement for closed systems such as refrigerants in nuclear power plants or for blood flow in the vascular system , material testing, machining, soldering and soldering, electronics, agriculture, oceanography and medical imaging. The various methods for producing and applying ultrasonic energy and commercial suppliers of ultrasound equipment are well known among those in ultrasound technology. The time of exposure of the emulsion to ultrasound is not critical to the practice or success of the invention and the optimum exposure time will vary according to the material being treated. In general, however, effective and useful results can be obtained with a relatively short exposure time. Better results will generally be obtained with exposure times ranging from approximately 8 seconds to approximately 150 seconds. For starting materials with API gravities of about 20 to about 30, the preferred exposure time is from about 8 seconds to about 20 seconds, while for fuels with API gravities of about 8 to about 15, the preferred exposure time is from about 100 seconds to about 150 seconds. After exposure to ultrasound, the emulsion is preferably allowed to separate immediately into aqueous and inorganic phases, the organic phase is the converted starting material, recoverable from the aqueous phase by conventional means. Improvements in the efficiency and effectiveness of the process can in many cases be obtained by performing ultrasound exposure in a continuous process in a through-flow ultrasonic chamber and even further improvements can be obtained by recycling the organic phase to the chamber with a supply new water Recycling can be repeated for a total of three passes through the ultrasound chamber for even better results. Alternatively, the organic phase emerging from the ultrasound chamber can be subjected to a second stage ultrasound treatment in a separate chamber and possibly a third stage ultrasound treatment in a third chamber, with a new water supply to each chamber. Ultrasound commonly generates heat and in certain embodiments of this invention it is preferable to remove some of the heat generated from the general heat to maintain control over the reaction. The heat can be separated by conventional means, such as a liquid coolant jacket or a coolant circulating through a cooling coil inside the ultrasound chamber. Water at atmospheric pressure is an effective coolant for this process. When the cooling is obtained by immersing the ultrasound chamber in a coolant bath or by using a circulating coolant, the coolant may be at a temperature of about 50 ° C or less, preferably about 20 ° C or less and more preferably in the range of about -5 ° C to about 20 ° C. Appropriate cooling methods or devices will be readily apparent to those skilled in the art. The operating conditions in general for the practice of this invention can vary widely, depending on the material being treated and the manner of treatment. The pH of the emulsion, for example, can range from as low as about 1 to as high as 10, although it is currently believed that better results are obtained in a pH range of 2 to 7. The pressure of the emulsion as is exposed to ultrasound can also vary, fluctuating from sub-atmospheric (as low as approximately 0.34 atmospheres or 5 pounds absolute force / square inch) to as high as 214 atmospheres (3000 pounds absolute force / square inch), though preferably less about 27 atmospheres (400 pounds absolute square inch strength) and more preferably less than about 3.4 atmospheres (50 pounds absolute force / square inch) and more preferably from atmospheric pressure to about 3.4 atmospheres (50 pounds force / square inch) absolute).

The process can be carried out either in a batch manner or in a continuous flow operation. Continuous flow operations are preferred. In a currently preferred system, ultrasound exposure is performed in a horizontal tube reactor, 30.5 cm (12 inches) in diameter and 1.83 m (6 feet) in length, although a useful range of dimensions can be a diameter of 10.2. cm to 61 cm (4 inches to 24 inches) and a length of 30.5 cm to 1.524 cm (1 foot to 50 feet), preferably 183 cm to 366 cm (6 feet to 12 feet). The tube is divided longitudinally into 5 sections or cells with vertical perforated walls that separate the cells. A horizontal screen in each cell supports the metal catalyst particles and the perforated vertical walls serve to retain the particles in each cell. The ultrasound probes penetrate the top of the tube and extend into the tube, a probe extends to each cell. The emulsion is passed through the tube and thus through each cell in succession, at a rate of about 4.7 liters / second (75 gallons / second or 2,570 pounds / day). The volumetric ratio of organic to aqueous phases is 1: 0.5. An alternative reactor is a single chamber continuous flow reactor, such as described in co-pending US Patent Application No. 10 / 440,445, filed May 16, 2003, entitled "High-Power Ultrasonic Generator and Use in Chemical Reactions ", Rudolf W. Gunnerman and Charles I. Richman, inventors. Application No. 10 / 440,445 is incorporated herein by reference. The following example is offered for purposes of illustration and is not intended to limit the scope of the invention.

EXAMPLE An average crude oil from Arabia that had been subjected to primary distillation, that is, whose light ends had been separated, was combined with water at a volumetric ratio of 60:60, with an additive consisting of diethyl ether dissolved in kerosene a a volumetric ratio of ether: kerosene of 1:10 and 1 part by volume of the ether / kerosene mixture was added to 1,000 parts of crude oil. The resulting emulsion was exposed to ultrasound in a batch process at a frequency of 17.5 MHz and a power level of 4 kilowatts for approximately 10 seconds. Then the emulsion was separated into aqueous and inorganic phases. Both the oil product and the oil before the treatment were analyzed by simulated high temperature distillation (HTSD), a gas chromatography technique that is known in the art and described by Villalanti, D.C., et al. in "High Temperature Simulated Distillation Applications in Petroleum Characterization", Encyclopedia of Analytical Chemistry, Meyers, R.A., ed., pp. 6726-6741 (John Wiley &Sons Ltd., Chichester, 2000) and ASTM method D5236095, "Test Method for Distillation of Heavy Hydrocarbon Mixtures (Vacuum Potsill Mixtures)", Annual Book of ASTM Standards, vol. 05.03, American Society for Testing and Materials, Philadelphia, 1998. This analysis is performed on a chromatography column with a non-polar stationary phase, the elution times of the hydrocarbon components are calibrated to the atmospheric boiling point of a wax of polyolefin hydrogenated POLYWAX 665 and covering a boiling range of 36-750 ° C (97-1382 ° F), covering n-alkanes with chain lengths of C5-C12o - The results, expressed as graphs of the cumulative volume distilled in Percent volume of liquid against the true boiling point in degrees Fahrenheit, are shown in Figure 1, in which the starting material is represented by squares and two tests of the treated material are represented by diamonds and triangles, respectively. It is clear from the graph that the analysis of the treated material was reproducible and that the distribution of the boiling point of the material was displaced downwards along the entire curve, with a maximum displacement of 25-30 ° F in the boiling range of approximately 400-600 ° F.

CLAIMS 1. A process for the treatment of an oil residue to convert the components of the waste having boiling temperatures ranging from about 204 ° C (400 ° F) to about 426.7 ° C (800 ° F) before the treatment of the products to products having boiling points that are lower by at least about 11 ° C (20 ° F), the method is characterized in that it comprises: (a) combining the petroleum residue with an aqueous liquid to form an emulsion, (b) exposing the emulsion to ultrasound, (c) recovering an organic phase of the emulsion after exposure. 2. The process according to claim 1, characterized in that step (a) comprises combining the petroleum residue with the aqueous liquid at a volumetric ratio (petroleum residue): (aqueous liquid) of about 8: 1 to about 1 :5. 3. The process according to claim 1, characterized in that step (a) comprises combining the petroleum residue with the aqueous liquid at a volumetric ratio (petroleum residue): (aqueous liquid) of about 5: 1 to about 1 :1. 4. The process according to claim 1, characterized in that step (a) comprises combining the petroleum residue with the aqueous liquid at a volumetric ratio (petroleum residue): (aqueous liquid) of about 3: 1 to about 1 :1. 5. The process according to claim 1, characterized in that step (b) is carried out at a frequency that fluctuates from about 30 KHz to about 300 MHz. 6. The process according to claim 1, characterized in that the step ( b) is carried out at a frequency that fluctuates from about 1 MHz to about 100 MHz. 7. The process according to claim 1, characterized in that step (b) is carried out at an exposure time of about 8 seconds to about 150. seconds .

Claims (1)

1. SUMMARY OF THE INVENTION Oil residues are described which are combined with water or an aqueous solution to form an emulsion which is then treated with ultrasound at a sufficient intensity and for a period of time sufficient to cause the conversion of the heavy hydrocarbon components. from the residues to lighter components, thereby displacing the entire curve from the boiling point to lower boiling points. This allows a greater proportion of usable oil to be extracted from the waste. # s > N * < ? «Á > -P ^ '- * > < d < * J > ? , ^? < # $ P > Qíf? < & ^ Temperature of F TBP FIG. 1