RU2184762C2 - Method of lowering summary acid number of oil feedstock - Google Patents

Abstract

FIELD: crude oil treatment. SUBSTANCE: process includes following stages: (i) addition to oil feedstock of catalytic agent containing oil-soluble or oil-dispersible compound of metal selected from VB, VIB, VIIB, and VIII group metals, concentration of metal in oil feedstock being at least 5 ppm; (ii) heating of oil feedstock with catalytic agent in reactor at 400 to 800^°F, and hydrogen pressure 15 to 1000 psig; (iii) blowing of reactor contents with hydrogen-containing gas with gas intake sufficient to maintain total water-carbon dioxide pressure below approximately 345 kPa. EFFECT: reduced proportion of carboxylic acids in oil feedstock. 10 cl, 1 dwg, 3 tbl, 7 ex

Description

 The present invention relates to methods for reducing the total acid number (OKC) of petroleum feedstocks, the value of which is related to the amount of carboxylic acids, especially naphthenic acids, which are present in oil.

 The presence of a relatively high level of petroleum acids, for example naphthenic acids, in crude oil or its fractions is a problem for refineries and, more recently, for manufacturers. Essentially, these acids, which are to a greater or lesser extent in almost any petroleum feedstock, have corrosive properties, tend to cause equipment malfunctions and lead to higher maintenance costs, more frequent work cycles than necessary without them, and lower quality products and cause problems associated with waste disposal.

A significant amount of literature has appeared, both patents and publications related to the removal of naphthenic acids by processing or absorption. For example, many aqueous substances can be added to oil or oil fractions to convert naphthenic acids to some other substances, for example salts, which can be removed or have less corrosion. Other methods for removing naphthenic acids, including absorption, for example on zeolites, are also well known. In addition, another common practice for overcoming the naphthenic problem is the use in equipment of processing plants and manufacturers in contact with relatively high concentrations of naphthenic acids, expensive corrosion-resistant alloys. Another common practice is to mix high-TOC petroleum feedstocks with lower TOC petroleum feedstocks; the latter, however, is significantly more expensive than the former. In one of the sources (US 1953353), Lazar et al., A method is described for the decomposition of stripped oil or distillates, carried out at atmospheric pressure and a temperature between 600 and 750 ^o F (from 316 to 399 ^o C). However, it only considers CO ₂ as the only gaseous non-hydrocarbon decomposition product of naphthenic acids and does not provide the opportunity to avoid the accumulation of reaction inhibitors.

In addition, US Pat. No. 2,921,023 describes the removal of naphthenic acids from heavy oil fractions by hydrogenation using a molybdenum oxide catalyst on silica / alumina. More specifically, oxo compounds and / or olefinic compounds, for example naphthenic acids, are selectively hydrogenated in this way in the presence of sulfur compounds contained in organic mixtures without affecting sulfur compounds. This is accomplished by the action of hydrogen on the organic mixture at temperatures in the range of about 450 to 600 ^° F. (232 to 316 ^{° C.} ) in the presence of a catalyst containing molybdenum oxide and having a reversible water content of less than 1.0 wt.%. The life of the catalyst is extended by regeneration.

WO 96/06899 describes a method for removing a significant amount of naphthenic acids from liquid petroleum products. The method includes hydrogenation under pressure from 1 to 50 bar (from 0.1 to 5 MPa) and at a temperature of from 100 to 300 ^o C (from 212 to 572 ^o F) of crude oil, which has not been subjected to preliminary distillation or from which gasoline is distilled ligroin fraction using a catalyst containing Ni-Mo or Co-Mo on an alumina support. The description of the application describes the injection of hydrogen into the reaction zone. There is no mention of regulating the partial pressure of water and carbon dioxide.

 US Pat. No. 3,617,501 describes an integrated process for refining unbroken oil, but does not discuss the reduction of OCC. The first step of the method involves hydrotreating the feed, which may be an unbranched oil fraction, using a catalyst containing one or more metal supported on a carrier material. Preferably, the metals are metal oxides or sulfides, such as molybdenum, tungsten, cobalt, nickel and iron, supported on a suitable carrier such as alumina or alumina containing a small amount of silica. The catalyst may operate in a fixed bed, a catalyst slurry, or in a fluidized bed reactor. Regarding the handling of the catalyst slurry, there is no mention of the particle size of the catalyst, the concentration of the catalyst in the feed, or the use of unsupported catalysts (i.e. without a carrier).

 British patent 1236230 describes a method for removing naphthenic acids from distillate oil fractions by treatment on supported hydrotreating catalysts without adding gaseous hydrogen. There is no mention of regulating the partial pressures of water and carbon dioxide.

US Pat. Nos. 4,134,825, 4,740,295, 5,039,392 and 5,620,591, each of which is incorporated herein by reference, describe the preparation of finely dispersed non-supported catalysts with a single micron nominal particle size of oil soluble or oil dispersible metal compounds selected from groups IVB , VB, VIB, VIIB and VIII of the Periodic system of elements, and the use of these catalysts for hydroconversion refinement of heavy raw materials, including unbranched or topped petroleum feed. By hydroconversion in these patents is meant a catalytic process carried out in the presence of hydrogen, in which at least a portion of the heavy components and coke-forming substances (i.e., Conradson carbon) are converted to lower boiling substances. The widest ranges mentioned in these references regarding process conditions include temperatures in the range 644-896 ^° F (339.9 to 480 ^° C), partial pressures of hydrogen of 50 to 5000 psi, or psig (from 446.08 to 34516.33 kPa), and the metal content of the catalyst is from 10-2000 mass parts per million (mcm) with respect to the weight of the feed. These references relate to the conversion refinement of heavy feedstocks and do not take into account that these catalysts can be used for the selective decomposition of carboxylic acids, for example naphthenic acids.

Another method for removing such acids, as described in WO 96/25471, involves treating at a temperature of not lower than about 400 ^° F. (204.44 ^° C.), preferably not lower than about 600 ^° F. (315.56 ^° C.) during zone purging. inert gas reactions to remove inhibitors characteristic of such treatment or obtained during such treatment. However, this method is carried out due to the volatilization of some naphthenic acids that are in the distillate and light oil fractions that evaporate during heat treatment. Moreover, the processing temperatures may be too high to use this method in other applications where it is desirable to destroy the acids before they enter the tube distillation furnaces, i.e. at temperatures of about 550 ^° F. (287.78 ^° C.) or lower.

 Thus, there remains a need to remove, or at least substantially reduce, the concentration of petroleum acids in crude oil or its fractions at low cost and in a manner favorable for refining. Such a technique would be particularly suitable for crude oil or fractions in which an OCC is about 2 mg KOH / g oil or higher, as determined by ASTM D-664.

The present invention relates to a process for breaking down carboxylic acids in crude oil and oil fractions. The invention includes a method of reducing the amount of carboxylic acids in an oil feedstock, comprising the steps of: (a) adding to the specified oil feed a catalytic agent containing an oil soluble or oil dispersible metal compound selected from the group consisting of metals VB, VIB, VIIB and VIII groups, while the amount of metal in the specified crude oil is at least 5 mass parts per million (mcm); (b) heating said petroleum feed with said catalytic agent in a reactor at a temperature of from about 400 to about 800 ^° F. (from about 204.44 to about 426.67 ^{° C.} ), at a hydrogen pressure of from 15 psig to 1000 psig (from 204 75 to 6996.33 kPa); and (c) purging the reactor containing said petroleum feed and said catalytic agent with a hydrogen-containing gas at a rate sufficient to maintain the combined partial pressure of water and carbon dioxide lower than about 50 psia (about 344.75 kPa).

OCC is defined as the mass (in milligrams) of potassium hydroxide required to neutralize all acidic components in one gram of oil (See ASTM Method D-664.)
The conversion of the vacuum distillation residue is defined as the conversion of a material with a boiling point above 1025 ^° F (551.67 ^° C) to a material with a boiling point below 1025 ^° F (551.67 ^° C).

BRIEF DESCRIPTION OF THE DRAWINGS
The drawing shows the calculated partial pressure of water as a function of the pressure in the reactor from the flow rate of the hydrogen-containing gas stream in the process of the present invention.

 The present invention removes or destroys carboxylic acids (e.g., naphthenic acids) contained in petroleum feedstocks, such as crude oil (including heavy oil) and fractions thereof, such as vacuum gas oil fractions, stripped oil, vacuum residue, atmospheric residue and vacuum gas oil. The present method reduces OCC in petroleum feeds by at least 40%.

The method is carried out at temperatures from about 400 to 800 ^o F (from about 204.44 to about 426.67 ^o C), more preferably from about 450 to 750 ^o F (from about 232.22 to 398.89 ^o C), and most preferably about 500 to 650 ^° F. (about 260.00 to 343.33 ^{° C.} ). Hydrogen pressure varies from atmospheric to about 2000 psig (from atmospheric to about 13891.33 kPa), preferably from about 15 psig to about 1000 psig (from about 204.75 to about 6996.33 kPa), and most preferably from about 50 psig to about 500 psig (from about 446.08 to about 3548.83 kPa). The amount of catalyst, calculated on the catalytic metal or metals used in the process, varies from at least 5, preferably about 10, to about 1000 mass parts per million (mcm), most preferably about 20 to 500 mass parts per million of petroleum processed raw materials.

Preferably, during the process of the present invention, approximately less than 40% of the feed component after vacuum distillation, i.e. fractions with a boiling point above about 1025 ^o F (551.67 ^o C), turned into a material with a boiling point below about 1025 ^o F (551.67 ^o C), and more preferably, approximately less than 30% of the residue from vacuum distillation was conversions.

 The particle size of the catalyst varies from about 0.5 to about 10 microns (microns), preferably from 0.5 to 5 microns, most preferably from 0.5 to 2.0 microns. The catalysts are prepared from catalyst-forming substances, also referred to as catalytic agents in the present invention, such as oil soluble or oil dispersible group VB, VIB, VIIB or VIII metal compounds or mixtures thereof. Suitable catalytic metals or metal compounds are described in US Pat. No. 4,134,825, incorporated herein by reference. An example of an oil soluble compound is a naphthenic acid salt, for example, molybdenum naphthenate. Examples of oil dispersible compounds are phosphoric molybdenum acid and ammonium heptamolybdate, materials that are first dissolved in water and then dispersed in oil as a water-oil mixture in which the drop size of the aqueous phase is less than about 10 microns.

 Ideally, a catalyst-forming concentrate is first prepared in which a metal compound (s) soluble or dispersible in oil is mixed with a portion of the processed feed to obtain a concentrate containing at least about 0.2 wt.% Catalytic metal, preferably from 0.2 to 2.0 wt.% Catalytic metal. The resulting catalyst-forming concentrate can be used directly in the process or first, before its use, can be converted into a metal sulfide concentrate or into an activated catalytic concentrate.

The catalyst-forming concentrate can be converted to a metal sulfide concentrate by treatment with elemental sulfur (added to a portion of the raw materials used to prepare the concentrate) or hydrogen sulfide at a temperature of from 300 to 400 ^o F (from 148.89 to 204.44 ^o C) for 10-15 minutes (see, for example, US patents 5039392, 4479295 and 5620591, incorporated herein by reference).

The metal sulfide concentrate can be converted into a catalytic concentrate by heating at a temperature of from 600 to 750 ^o F (from 315.56 to 398.89 ^o C) for the time required to obtain a catalyst (see, for example, US patents 5039392, 4740295 and 5620591). The catalyst in the concentrate consists of nano-scale centers of metal sulfide, distributed on a hydrocarbon matrix obtained from the oil component of the concentrate. The average particle size may vary, but is in the range of 0.5 to 10 microns, preferably in the range of about 0.5 to 5.0 microns, and more preferably 0.5 to 20 microns.

 In the present method, a catalyst-forming substance concentrate, a metal sulfide concentrate or a catalyst concentrate can be used. In each case, the crude oil is mixed with the concentrate to obtain the desired metal concentration in the feed, i.e. at least 5 mass parts per million, preferably from 10 to 1000 mass parts per million. When a catalyst-forming substance concentrate or a metal sulfide concentrate is used, a catalyst with a particle size of from about 0.5 to 10 microns, preferably from 0.5 to 5 microns, most preferably from 0.5 to 2, is obtained at the stage of heating in the OKC conversion reactor. 0 microns.

Preferred metals include molybdenum, tungsten, vanadium, iron, nickel, cobalt and chromium. For example, metal heteropoly acids may be used. Particularly suitable in the method of the present invention is molybdenum. Preferred molybdenum compounds are molybdenum naphthenates, dithiocarbamate complexes of molybdenum (see., E.g., U.S. Patent 4,561,964, incorporated herein by reference), phosphomolybdic acid and phosphorodithioate complexes of molybdenum (e.g., MOLYVAN ^® -L, di (2-ethylhexyl) phosphorodithioate molybdenum supplied by RT Vanderbilt Company.

 Other particulate catalysts suitable for use in the process of the invention include metal-rich fly ash resulting from controlled combustion of petroleum coke (see, for example, US Pat. Nos. 4,166,038, 4,169,038 and 4,204,943, incorporated herein by reference). It is also possible to use finely ground iron-based materials that satisfy the aforementioned particle size restrictions, such as red mud obtained in aluminum production technology.

 Water vapor and carbon dioxide resulting from the decomposition of carboxylic acids act as inhibitors of the decomposition of residual carboxylic acids. Water is a particularly powerful inhibitor. Thus, if the feed to the process contains water, a pre-evaporation step can be used to remove substantially all of the water. Moreover, traces of water entering the process together with the raw materials, like water and carbon dioxide produced during the destruction of carboxylic acids, must be removed so that the partial pressure of water and carbon dioxide in the reaction zone is kept below about 50 psia (about 344.75 kPa), preferably below about 30 psia (about 206.85 kPa), more preferably below about 20 psia (about 137.9 kPa) and most preferably below about 10 psia (about 68.95 kPa). Essentially all water, as mentioned in the present invention, means as much water as can be removed by methods known to those skilled in the art.

 Without being bound by theory, it can be noted that, apparently, the sources of the formation of water and carbon dioxide in this method for reducing OCC can be described by the following equations. The decomposition of carboxylic acids by hydrogen has the potential to form two moles of water per mole of decomposed acid (Equation A) or one mole of water per mole of decomposed acid (Equation B). Thermal reactions that can compete with decomposition form half a mole of water per mole of decomposed acid (Equation C).

Как будет показано на примерах, приведенных ниже, вода может обладать сильным ингибирующим эффектом на степень разложения карбоновых кислот. Диоксид углерода также является ингибитором, но в значительно меньшей степени.Equation A
RCHOOH + 2H ₂ -> RCH ₃ + 2H ₂ O
Equation B
RCHOOH + H ₂ -> RCH ₂ (OH) ₂ -> H ₂ O + RCHO
RCHO -> RH + CO
Equation C

As will be shown in the examples below, water can have a strong inhibitory effect on the degree of decomposition of carboxylic acids. Carbon dioxide is also an inhibitor, but to a much lesser extent.

 To illustrate the potential for increasing water pressure occurring during the decomposition of carboxylic acids under the conditions claimed in the method of the present invention, a hypothetical option was adopted in which the TOC of crude oil was lowered from 5.3 to 0.3 by heat treatment in a temperature range set by further in the present invention, and for each mole of decomposed acid, 1.25 moles of water were formed. The calculated partial pressures of water are shown in the drawing as a function of the pressure in the reactor and the flow rate of the purge gas (i.e., hydrogen-containing gas). Given that the partial pressure of water of the order of 72 psia (496.44 kPa) or higher can be achieved only by acid decomposition, it is preferable to start the process with dry raw materials and maintain the flow of purge gas in order to keep the water pressure within certain limits.

 From the point of view of the method, the catalyst can be left in the processed oil (depending on the type of metal and concentration) or removed by any suitable method, for example by filtration.

 Another aspect of the present invention relates to the content of Conradson carbon in the product, i.e. product components that form coke under pyrolysis conditions. In thermal processes, such as cracking, Conradson's carbon content in the product increases relative to its content in the feed. This effect is illustrated in comparative example 5 in table 2. In the range of conditions for implementing the method according to the invention, the increase or increase in the carbon content of Conradson can be completely inhibited, and the carbon components of Conradson can be converted into non-Konradson carbon components. Preferably, Conradson's carbon conversion is in the range of about 0 to 5%, more preferably about 5 to 20%, most preferably 10 to 40%.

 The following examples illustrate the invention without limiting it in any way.

In this study (table 1), two raw materials were used. One of them is an oil mixture of Côme and Bolobo located in Chad. Other raw materials are the very heavy Campo-1-Bare oil from Venezuela. Both raw materials were heated to 230 ^° F. (110 ^{° C.} ) with nitrogen purge prior to use to remove most of the water.

Example 1
This example was carried out in an autoclave reactor with a stirrer, a volume of 300 cubic meters. see. The reactor was operating in periodic oil loading mode. A stream of hydrogen passed through an autoclave to achieve a constant partial pressure of hydrogen and to control the pressure of water and carbon dioxide in the reaction zone.

The reactor was filled with 100 g of the Comé / Bolobo mixture and 0.61 g of MOLYVAN ^® -L ^* (8.1 wt.% Mo), washed with hydrogen, and then the pressure was increased to 350 psig (2514.58 kPa), using a back pressure regulator at the outlet of the reactor. The reactor was then heated to 625 ^° F (329.44 ^° C) with stirring and held at 625 ^° F (329.44 ^° C) for 60 minutes and at a pressure of 350 psig (2514.58 kPa). The calculated partial pressures of hydrogen and water ** were 329 psia (2268.46 kPa) and 13 psia (89.64 kPa), respectively. The partial pressure of carbon dioxide was less than 0.1 psia (less than 0.7 kPa). After cooling to 250 ^° F (121.11 ^° C), the reactor was opened and washed with hydrogen to isolate light hydrocarbon products, including hydrocarbons, which are usually in gaseous form at room temperature. Then the oil from the reactor was discharged, combined with the liquid hydrocarbon removed during the opening of the reactor, and the mixture was analyzed for total acid number (OKC) using the ASTM D-664 method, with OKC = mg KOH per gram of oil (or oil product). The measured OKC was 0.43.

 * MOLYVAN®-L supplied by R.T. Vanderbilt Company, is a molybdenum di (2-ethylhexyl) phosphorodithioate.

 ** Assuming a maximum of 1.25 moles of water resulting from the decomposition of a mole of acid.

Example 2 (Comparative)
This example illustrates the degree of OCC conversion achieved by heating the Comé / Bolobo oil mixture at 625 ^° F (329.44 ^° C) for one hour in the absence of catalyst and hydrogen. The procedure was repeated as in example 1, except that MOLYVAN®-L was excluded and the process was carried out with an inert gas purge at a reactor pressure of 30 psig (308.18 kPa). The partial pressure of carbon dioxide was 6.5 psia (45 kPa). TAN for the reaction products was 3.40.

 Conclusions from the examples with the Comé / Bolobo oil mixture.

 Example 1 illustrates the decrease in OKC in Coma / Bolobo oil (Table 2) when using a small amount of highly dispersed catalyst under relatively mild conditions and at a partial pressure of water in the reactor below 20 psia (137.9 kPa). This treatment provides a significantly greater reduction in OKC than what can be achieved only by heat treatment for a comparable time and at the same temperature (Example 2).

Example 3
In this example, Campo-1-Bare dry oil was used as feed. Mo was supplied as a catalyst-forming concentrate, which was prepared as follows. 8 g of a solution of phosphoric-molybdenum acid with a purity corresponding to Fisher's reagent was dissolved in 92 g of deionized water. Then, 10 g of the solution was added while stirring in 90 g of Campo-1-Bare oil at a temperature of 176 ^° F (80 ^° C) into a 300 cc magnetic drive autoclave (Engineer's Magnedrive Autoclave). After stirring for 10 minutes at a temperature of 176 ^° F (80 ^° C), the autoclave was purged with nitrogen and the temperature was raised to 300 ^° F (148.89 ^° C) to remove water. The resulting concentrate contained 0.45 wt.% Mo.

The autoclave was filled with 99.43 g of Campo-1-Bare dry oil and 0.57 g of forming concentrate to ensure loading of the reactor, which contained 25 parts by mass of Mo per million. The reactor was washed with hydrogen, and then the pressure in it was increased to 50 psig (446.08 kPa) with hydrogen sulfide. After heating with stirring for 10 minutes at a temperature of from 350 to 400 ^o F (from 176.67 to 204.44 ^o C), the pressure in the reactor was increased to 300 psig (2169.83 kPa) with hydrogen, and hydrogen was passed through the autoclave with 0.12 l / min flow rate (380 standard cubic feet / barrel, or SCF / B). The pressure was maintained by a backpressure regulator at the gas outlet of the reactor. The temperature was raised to 725 ^° F (385.00 ^° C) during the reaction with stirring for 120 minutes. The partial pressure of water in the reactor was calculated to be 5.5 psia (37.92 kPa) (based on 1.25 moles of water per mole of degraded acid). The partial pressure of carbon dioxide was less than the lower limit of detection (which was 0.1 psia, or 0.7 kPa). The reactor was opened, the pressure in it was reduced to atmospheric at a temperature of 250 ^o F (121.11 ^o C), and the oil remaining in the reactor was filtered at a temperature of from 180 to 200 ^o F (from 82.22 to 93.33 ^o C) to remove 0.03 g of a residue containing a catalyst. The filtered oil from the reactor was combined with light liquids that were removed from the reactor during the process and subsequent opening step. The combined liquid products, whose weight was 96.6 g, had an OCC equal to 0.10 (mg KOH / g mixture) and contained 15.9 wt.% Conradson carbon.

Example 4 (Comparative)
The procedure was repeated as in example 3, except that the process was carried out under a pressure of 400 psig (2859.33 kPa), and water entered the reactor at a rate of 0.033 g / min. The partial pressure of water in the reactor during the process was approximately 92 psia (634.34 kPa). The partial pressure of carbon dioxide was less than the lower limit of detection (which was 0.1 psia, or 0.7 kPa). 0.05 g of a residue containing a catalyst and 96.4 g of a liquid mixture of products with a TAN of 0.43 and a Conradson carbon content of 15.4 wt.% Were isolated.

Example 5 (Comparative)
The procedure was repeated as in example 4, except that the catalyst was not added, the experiment was carried out under a pressure of 300 psig (2169.83 kPa), and argon was used as the purge gas. 97.4 g of a liquid mixture of products with an OKC of 0.63 and a Conradson carbon content of 17.9 wt.% Were isolated. The partial pressure of water in the reactor was 92 psia (634.34 kPa). The partial pressure of carbon dioxide was less than the lower limit of detection (which was 0.1 psia, or 0.7 kPa).

Example 6 (Comparative)
The procedure was repeated, as in example 3, with the following changes. The reactor was filled with 98.86 g of oil and 1.14 g of forming (catalyst) concentrate to ensure loading of the reactor containing 50 mass parts of Mo per million. The process was carried out at 750 ^o F (398.89 ^o C) for 62 minutes under a pressure of 300 psig (2169.83 kPa) with a hydrogen purge with a flow rate of 0.12 l / min (380 SCF / B). Water was introduced into the reactor at a rate of 0.017 g / min to provide a partial pressure of water in the reactor of 55 psia (379.22 kPa). The partial pressure of carbon dioxide was less than the lower limit of detection (which was 0.1 psia, or 0.7 kPa). 0.05 g of catalyst residue and 97.3 g of a mixture of liquid products with a TAN of 0.31 and a Conradson carbon content of 15.2 wt.% Were recovered.

Example 7
The procedure was repeated as in example 6, except that the hydrogen flow rate for purging was 0.24 l / min (780 SCF / B), which affected the partial pressure of water in the reactor equal to 26 psia (179.27 kPa) . The partial pressure of carbon dioxide was less than the lower limit of detection (which was 0.1 psia, or 0.7 kPa). 0.04 g of catalyst residue and 96.8 g of a mixture of liquid products with an OCC equal to 0.12, containing 15.4 wt.% Conradson carbon and with a kinematic viscosity equal to 918 centistokes at 104 ^o F (40 ^o C) were isolated . Conclusions by examples using Campo-1-Bare oil (Table 3).

 The comparison of example 3 with example 4 demonstrates the inhibitory effect of water on the conversion of OCC, which is also seen when comparing examples 6 and 7, in which a decrease in the partial pressure of water from 55 to 26 psia (from 379.22 to 179.27 kPa) reduced OCC from 0 , 31 to 0.12. Comparison of example 4 with example 5 shows that the use of a catalyst with hydrogen in accordance with the method of the present invention gives a higher OCC conversion at a given partial pressure of water compared to what can be achieved by heat treatment in the absence of hydrogen and a catalyst.

 The amount of carbon Conradson was determined using a micromethod (Micro Method) according to ASTM D 4530. This test determines the amount of carbon residue formed after evaporation and pyrolysis of petroleum products under certain conditions. The test results are equivalent to the results obtained using the Conradson residual carbon test (Analysis Method D 189).

Claims (10)

1. A method of reducing the amount of carboxylic acids in a petroleum feed, comprising adding a catalytic agent to said petroleum feed, heating said petroleum feed with said catalytic agent in a reactor, characterized in that the method comprises the steps of: (a) adding a catalytic agent to said petroleum feed, containing a soluble in oil or dispersible in oil compound of a metal selected from the group consisting of metals of groups VB, VIB, VIIB, VIII, while the amount of metal in the specified oil feedstock S THE at least 5 wt. ppm (b) heating said petroleum feed with said catalytic agent in a reactor at a temperature of about 400-800 ^° F (about 204.44-426.67 ^° C), under a hydrogen pressure of 15-1000 psig (204.75-6996.33 kPa) ), and (c) purging the reactor containing said petroleum feed and said catalytic agent with hydrogen-containing gas at a flow rate sufficient to maintain the combined partial pressure of water and carbon dioxide below 50 psia (344.75 kPa).  2. The method according to p. 1, characterized in that said catalytic agent contains a catalyst-forming concentrate of an oil-soluble or oil-dispersible metal compound prepared in an oil feed selected from the group consisting of whole crude oil, stripped oil, atmospheric residue, vacuum residue, gas oil and mixtures thereof.  3. The method according to p. 1, characterized in that said catalytic agent contains a metal sulfide concentrate from an oil-soluble or oil-dispersible metal compound prepared in petroleum feedstock selected from the group consisting of whole crude oil, stripped oil, atmospheric residue , vacuum residue, vacuum gas oil and mixtures thereof.  4. The method according to p. 3, characterized in that the metal sulfide concentrate is heated at a temperature and for a time sufficient to obtain a dispersion of catalyst particles of 0.5-10 microns in size, which contain a metal sulfide component in combination with a carbon solid component obtained from said petroleum feedstock in which said metal sulfide is dispersed.  5. The method according to p. 1, characterized in that said catalytic agent is a dispersion of 0.5 to 10 μm catalyst particles that contain a metal sulfide component in combination with a carbon solid component obtained from said petroleum feedstock.  6. The method according to p. 1, characterized in that said metal is selected from the group consisting of molybdenum, tungsten, vanadium, iron, nickel, cobalt, chromium and mixtures thereof.  7. The method according to p. 1, characterized in that said oil-soluble or oil-dispersible metal compound is a heteropoly acid of tungsten or molybdenum.  8. The method according to p. 1, characterized in that said oil-soluble or oil-dispersible metal compound is selected from the group consisting of molybdenum phosphoric acid, molybdenum naphthenate and molybdenum dialkylphosphorodithioate.  9. The method according to p. 1, characterized in that the combined partial pressure of water and carbon dioxide is less than 30 psia.  10. The method according to p. 1, characterized in that the water is essentially removed from the crude oil to the specified stage of heating. Priority on points and signs:
08/29/1997 on pp. 1-10;
05/05/1997 PP 1-10 - refinement of signs.

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