ES2687687T3 - Process for desulfurization of petroleum oil - Google Patents

Abstract

Process for the desulfurization of petroleum oils, said process comprising the following steps: diluting petroleum oil with an organic hydrocarbon solvent selected from the group consisting of alkanes, alkenes, cyclic alkynes and alkynes, to obtain a mixture of oil- solvent, the ratio of the organic solvent with respect to the petroleum oil in the mixture of oil solvent in the range between 50:50 and 20:80, based on the weight in g of petroleum oil and the volume in ml of the solvent organic hydrocarbon in the mixture; transfer the oil-solvent mixture to a reactor vessel; adding solid metallic sodium to the oil-solvent mixture in the reactor vessel, the concentration of sodium being between 0.1 and 20% of the petroleum oil concentration, by weight; react the oil-solvent mixture with sodium at a temperature in the range between 240 and 350 ° C and a pressure in the range between 101 and 3,550 kPa (0 to 500 psig) for minutes to 4 hours under mixing to obtain a resulting mixture; cool and settle the resulting mixture; and decant the cooled mixture and filter the decanted solution of desulfurized petroleum oil.

Description

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DESCRIPTION

Process for desulfurization of petroleum oil.

Exhibition Field

This exhibition refers to desulfurization processes.

Particularly, the exposition refers to a process for the desulfurization of heavy petroleum oils and residual petroleum oils, more particularly, carbon black manufacturing oil.

Background

Petroleum oils are complex mixtures mainly of hydrocarbons and other carbon-containing compounds. The total composition of petroleum oil or crude oil is known to vary significantly from its origin or the geographical location of the refinery. The elemental composition of these oils consists of approximately carbon (84 to 87%), hydrogen (12 to 14%) together with oxygen, nitrogen, sulfur, moisture and ashes. The sulfur content can vary substantially from 0.2 to 8%. In addition to these main components, there are traces of metallic impurities, which may be present initially or may be associated with the oil during various stages of the refinery process. Crude oils may also contain hydrocarbons, paraffins, asphaltenes, resins and ashes. The crude oil compositions can be differentiated into several individual fractions with different boiling ranges. Fractions with a low boiling point (<170 ° C) are typically naphtha, those between 180 and 250 ° C are kerosene, and those with a boiling point in the range between 250 and 350 ° C are called diesel. . Fractions with a boiling point above 350 ° C are generally called waste, and are obtained after all or most of the distilled products have been removed from petroleum oil. These residual fractions could be further distinguished in light vacuum diesel, heavy vacuum diesel and vacuum waste. Each of these different fractions has a different molecular distribution of various species of hydrocarbons and related compounds. In particular, one of the significant aspects is the distribution of sulfur-containing species in these fractions. The use of petroleum oil waste includes heating (as fuel), and as a raw material for the manufacture of carbon black. The presence of sulfur in the petroleum oil residue has a number of drawbacks. During the complete or partial combustion of the petroleum residue, the sulfur becomes SO2 and SO3. These generate significant environmental problems in the form of acid rains and negatively affect health. In addition, sulfur species cause contamination of catalyst systems used in refineries. It is also known that they are the main reason for corrosion of equipment and exhaust gases. The presence of sulfur in the residual fraction has other ramifications if used as a starting material for the manufacture of carbon black. Apart from significant air pollution, these species remain associated with the final carbon black product which is harmful in various applications. In addition, a high sulfur content affects the performance of the manufacturing process.

Carbon black manufacturing oil (CBFO) is a starting material used to make carbon black, which is an important material used in the tire industry. The carbon black raw material is a mixture of C12 and higher components rich in naphthalene, methylindenes, anthracene, fluorene and other polyaromatic components. The CBFO is obtained essentially either from oil refineries or from coal tar distillation plants. There are two types of CBFO, specifically, the type with BMCI Alto and the General type. The “BMCI” (Mining Agency Correlation Index) effectively measures the degree of carbon black yield. The higher the BMCI, the better the carbon black yield. BMCI Alto CBFO is used as a starting material by carbon black manufacturers, while the other grade is used by various consumers to manufacture oils in rubber processes, incense sticks, and so on.

The sulfur content in the CBFO causes the effective value of the BMCI to be reduced. On the other hand, this sulfur is incorporated into the final product of carbon black in the form of impurity. Therefore, it is interesting to reduce the sulfur content of CBFO. Therefore, it would be interesting to discover a method for reducing the sulfur content of the petroleum oil residue that will be used as CBFO.

A desulfurization process is usually carried out to remove sulfur (S) from natural gas and petroleum products, such as gasoline, aviation fuel, kerosene, diesel fuel and fuel oil. The raw material of the refineries (naphtha, kerosene, diesel and heavier oils) contains a wide variety of organic sulfur compounds, including thiols, thiophenes, organic sulphides, disulfides and many others. These organic sulfur compounds are the products of the degradation of biological components that contain sulfur, present during the natural formation of the fossil fuel, the crude oil of petroleum. The purpose of removing sulfur is to reduce the sulfur dioxide (SO2) emissions that result from the use of these fuels in motor vehicles, aircraft, locomotives, vessels, gas or oil power plants, residential and industrial furnaces, and other forms of equipment that use fuel for combustion.

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To reduce the sulfur content of various fractions of petroleum oils, several techniques have been used that include catalytic transformation processes, such as hydrodesulphurization and physicochemical processes, such as solvent extraction, alkylation, oxidation, precipitation, adsorption, and the like Hydro-desulfurization is commonly used for this purpose. This process is based on the catalytic hydrogenation of sulfur species to convert them into H2S. However, it is known that hydrodesulfurization works efficiently on fractions with a lower boiling point, such as gasoline, naphtha, kerosene and the like. In general, catalyst systems include transition metals, such as Ni, Co, Mo, supported on AhO3. In the past several efforts have been made to provide a hydrodesulfurization technique. Some typical examples of the prior art are disclosed in US2516877, US2604436, US2697682, US2866751, US2866752, US2911359, US2992182, US3620968, US3668116, US4193864, US4328127, US4960506 and US5677259. Most of these processes are very suitable for the treatment of fractions with a lower boiling point or raw oils. However, its efficiency drops when fractions with a high boiling point or vacuum residues are treated. This is due to the fact that oil fractions with a lower boiling point contain, mainly, sulfur in the form of mercaptans or annular compounds with fewer members, which are relatively simpler to desulfurize. However, residual oils or high boiling fractions contain sulfur species that are part of the more stable ring compounds, such as substituted benzothiophenes and higher derivatives or large molecule ring compounds that are extremely difficult to desulfurize. Some examples of the prior art for treating hydrodesulfurization residues include documents US2640011, US2992182, US4328127 and US4576710. In most cases, the treatment parameters are extreme, that is, use of elevated temperatures above 400 ° C and pressures above 1,000 psig. On the other hand, desulfurization efficiencies are low. In addition, due to these difficult processing conditions, hydrodesulphurization results in coke formation, which results in deactivation of catalyst systems. In addition, the hydrodesulphurization process results in the formation of H2S, which, again, cannot be discarded due to its environmental connotations. This H2S needs to be further treated by means of the Claus process at an elevated temperature of approximately 800 ° C in the presence of Al2O3 catalyst for conversion into elemental sulfur.

In addition to hydrodesulfurization, there are several other techniques that are being explored for the desulfurization of petroleum oils. These include oxidative processes, by adsorption, by extraction with solvents and bioenzymes. Some typical examples of the prior art relating to the oxidative desulphurization process are disclosed in US3816301, US3163593, US3413307, US3505210, US3816301, US3847800, US6274785, US6277271, US7144499, US7179368, US7276151, US73505451, US73505451

US200600226049, US20080308463 and US20090148374. Common oxidizing agents used are H2O2 or H2O2 in combination with acetic acid and in the presence of an oxidizing catalyst system. In addition, as an oxidizer, ferf-butyl hydroperoxide can also be used since it tends to be oil soluble. In general, adsorption processes use absorbents such as clay, Al2O3, bauxite, transition metal oxide systems supported on silica or alumina, zeolites, activated carbon, and so on. Some typical examples of these processes are disclosed in documents US2436550, US2537756, US2988499, US3620969, US4419224, US4695366, US5219542, US5310717, US6558533, US6500219, US7291259, US20030029777, US2003018800990, US2006018800990, US2006018800990, US2006018800390 Solvent extraction processes use various solvent systems, such as dimethyl formamide, dimethyl sulfoxide, phenols, dichloroethers, nitrobenzene and the like. Some typical prior art processes are disclosed in documents US2486519, US2623004, US2634230 and US3779895. However, most of the aforementioned processes are intended for the desulphurization of crude oils or low boiling fractions. Similarly, most of the aforementioned processes (except bioenzymatic) are intended to focus and eliminate the entire sulfur-containing molecule instead of specifically eliminating the sulfur atom. This may not have a significant effect when considering the desulfurization of crude oil or fractions with a lower boiling point to the extent that the net sulfur content is lower and, in addition, sulfur would be distributed over a small number of low molecular weight compounds. However, in the case of residual oils in which the sulfur content can be up to 4 to 5%, the sulfur appears to be distributed essentially over a greater part of the molecules contained in the oil. Therefore, the removal of the entire sulfur-containing molecule would result in a substantial loss of material from the oil part.

Another desulfurization process of the aforementioned type is based on the use of alkali metal, especially metallic sodium as a desulfurizing agent. In this process, sulfur is removed primarily in the form of a metal sulfide instead of removing the entire sulfur-containing molecule. Some typical examples of the prior art of this process are documents US1938672, US1952616, US2902441, US3004912, US3093575, US3617530, US3755149, US3787315, US4003824, US4120779, US4123350, US4147612, US4248695,

US4437980, US6210564, US7192516, US7507327, US7588680. Thus, these documents describe the

desulfurization of crude oils and residual oils by metallic sodium. Metallic sodium can be used as pure metal or in an alloy, supported on inert species, or dissolved in solvent such as ammonia. In addition, these processes use hydrogen at elevated pressures in combination with metallic sodium for desulfurization. In some processes, sodium-based compounds such as desulfurization are used for desulfurization.

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NaHS, NaNH2, and the like. One of the main products formed as a reaction of metallic sodium with sulfur in the oil provided is sodium sulfide (Na2S). Some of the previously mentioned documents of the prior art also describe the regeneration of sodium from Na2S. These processes reveal the efficacy of recalcitrant sulfur desulfurization, especially that of residual oils with a high boiling point. However, these sodium-based desulfurization processes are associated with limitations, such as a low yield of the desulfurized oil provided, the formation of a large amount of insoluble sludge, the need for hydrogen and safety problems. The inherent high viscosity of heavy oils and petroleum residues makes it difficult for processing and separation operations before and after the desulfurization process. A large amount of valuable residual contributed oil remains associated with the precipitated residue of sodium sulphide or unreacted sodium in the form of a highly viscous sludge. In addition, the mud is extremely difficult to filter and separate due to its inherent viscosity and its sticky nature. Therefore, a substantial loss of contribution occurs during the process, especially during filtration or separation. In addition, due to the lower density of metallic sodium compared to that of residual oil, metallic sodium may tend to float on the surface of the oil and may result in a dangerous situation during failed reactions or during incomplete mixing.

GB441703 discloses a process for the desulfurization of petroleum oils, which comprises the following steps: transferring the petroleum oil to a reactor vessel, adding solid metallic sodium to the petroleum oil in the reactor vessel with a concentration of up to 20%, react the petroleum oil with sodium at a temperature in the range between 240 and 350 ° C under mixing, cool the resulting mixture, decant and filter.

US2007295640 discloses a composition for reducing the viscosity of heavy oils; nature of petroleum oil solvent: alkanes, alkenes; cyclic alkenes; n-hexane, cyclohexane, heptane, pentene, hexene, heptene; toluene and xylene; and concentration of petroleum oil solvent: 5 to 50%; Solvent separation and recovery is carried out by distillation.

US5935421 discloses a process for the desulfurization of petroleum oils, which comprises a stage in which solid metallic sodium is reacted with the oil in the temperature range between 260 and 400 ° C with a hydrogen pressure of 690 to 4,825 kPa (100 to 700 psi) and for the amount of treatment time from 2 to 90 minutes.

Therefore, known desulfurization processes are associated with a number of limitations, such as a low yield of the desulfurized input oil, the formation of a large amount of insoluble sludge, the need for hydrogen and safety problems. The inherent high viscosity of heavy oils and petroleum residues makes it difficult for processing and separation operations before and after the desulfurization process. A large amount of valuable residual contributed oil remains associated to the precipitated sulfur residue or to the unreacted sodium, in the form of a highly viscous sludge. In addition, the mud is extremely difficult to filter and separate due to its inherent viscosity and its sticky nature. A substantial loss of contribution occurs during the process, especially during filtration or separation. In addition, it was observed that sodium-based desulfurization processes result in the retention of metallic sodium in the oil. The presence of metallic sodium, even at a concentration as low as <100 ppm, results in a change in the carbon black morphology during manufacturing processes. Therefore, there is a need to develop a process to minimize the loss of contribution during the desulfurization of petroleum oils. The present invention is an improved process for the desulfurization of petroleum oil, especially the desulfurization of carbon black manufacturing oil (CBFO), which reduces the sulfur content in the oil.

goals

An objective of the present exhibition is to provide a process for desulphurization of oil for the manufacture of carbon black, which provides improved performance and high quality of desulfurized oil.

Another objective of the present exhibition is to provide a process for the desulfurization of oil for the manufacture of carbon black, with improved processing and handling operations.

Still another objective of the present exhibition is to provide a process for the desulfurization of oil for the manufacture of carbon black without the use of hydrogen.

Another objective of the present exposition is to provide a process for an additional treatment of the desulfurized oil in order to eliminate the residual sodium content.

Summary

In accordance with the present disclosure, as specified in claim 1, a process for the desulfurization of petroleum oils is provided, said process comprising the following steps:

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dilute petroleum oil with an organic hydrocarbon solvent selected from a group consisting of alkanes, alkenes, cyclic alkynes and alkynes, to obtain an oil-solvent mixture, where the ratio of the organic solvent to the petroleum oil in the oil-solvent mixture is in the range between 50:50 and 20:80, based on the weight in g of petroleum oil and the volume in ml of the organic hydrocarbon solvent in the mixture;

transfer the oil-solvent mixture to a reactor vessel;

adding solid metallic sodium to the oil-solvent mixture in the reactor vessel, where the sodium concentration is between 0.1 and 20% of the petroleum oil concentration, by weight;

react the oil-solvent mixture with sodium at a temperature in the range between 240 and 350 ° C and a pressure in the range between 101 and 3,550 kPa (0 to 500 psig) for 15 minutes to 4 hours, under mixing , to obtain a resulting mixture;

cool and settle the resulting mixture; Y

Decant the cooled mixture and filter the decanted solution of desulfurized petroleum oil.

Typically, in accordance with the present disclosure, the organic hydrocarbon solvent is selected from a group consisting of n-hexane, cyclohexane, heptane, pentene, hexene, heptene, octene, toluene and xylene.

Preferably, according to the present disclosure, the process includes the step of purging the reactor vessel with hydrogen gas at a pressure in the range between 101 and 3,550 kPa (0 to 500 psig).

Typically, according to the present disclosure, the process includes the step of separating the organic solvent from the desulfurized petroleum oil by distillation.

Preferably, according to the present disclosure, the process includes the step of mixing sodium with the oil-solvent mixture in the reactor vessel using a high shear mixing by means of a mixer selected from an in-line mixer, a mixer mechanical, a recirculating pumping loop (pump aroundloop) and an ultrasonic mixer.

In accordance with the present disclosure, a process is provided to remove residual metallic sodium, said process including the steps of: treating the desulfurized petroleum oil with carboxylic acid at between 0.1 and 10% in an organic solvent, by volume , at a temperature in the range between 50 and 150 ° C for 30 minutes to 90 minutes under vigorous stirring; and filter the resulting mixture to obtain desulfurized petroleum oil having a sodium content of between 10 and 50 ppm.

Typically, in accordance with the present disclosure, the carboxylic acid is selected from acetic acid, formic acid and propionic acid.

Preferably, in accordance with the present disclosure, the organic carboxylic acid solvent is selected from alkanes, alkenes, cyclic alkenes, alkynes and alcohol. More preferably, the organic carboxylic acid solvent is xylene.

In accordance with the present disclosure, a process is provided to remove residual metallic sodium by purging the desulfurized petroleum oil with air at a temperature in the range between 30 and 150 ° C.

Detailed description of the exhibition

The present exhibition refers to a process for desulfurization of oil for the manufacture of carbon black (CBFO). The oil provided (CBFo) has a high viscosity in environmental conditions. The process comprises diluting the oil provided with a suitable organic solvent, before the desulfurization reaction. The organic solvent can be selected from the group of hydrocarbon solvents consisting of alkanes, alkenes, cyclic alkenes and alkynes. Similarly, to dilute the oil provided, other oils, such as gasoline, kerosene, crude oil and the like, can also be used. The organic solvent is selected, in particular, from the group consisting of n-hexane, cyclohexane, heptane, pentene, hexene, heptene, octene, toluene and xylene, preferably the solvent is xylene. The ratio of the organic solvent to the petroleum oil in the oil-solvent mixture is in the range between 50:50 and 20:80, based on the weight in g of petroleum oil and the volume in ml of the solvent Organic hydrocarbon in the mixture.

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The material contributing to the process of the present exhibition is oil for the manufacture of carbon black that has a sulfur content in the range between 0.1% and 20%. The process of the present exposure can also be used for petroleum oils with fractions with various boiling points. In addition, the process of the present exposure can be used to desulfurize coal tar, shale oil or other sulfur-bearing organic compounds. The organic solvent is removed after the desulfurization process. The present process results in a desulfurized flow (after removal of xylene) with a substantial reduction in viscosity. The formation of insoluble sludge (unusable material) due to polymerization reactions of desulfurized species is reduced due to an improvement in the viscosity of the oil provided. In addition, the improvement in the viscosity of the contributed oil enhances the processing of the contributed oils that are required in applications, such as the manufacture of carbon black product.

The process results in an improvement in the quality of the oil provided, by reducing the content of asphaltenes in the oil provided. Asphaltenes are considered as the insoluble components in n-heptane, soluble in toluene, of a carbonaceous material, such as crude oil, bitumen or coal. Asphaltenes are high molecular weight heteroatomic species that, in general, are considered detrimental to the quality of the processed carbon black product.

The process of the present exposure is carried out in the absence of hydrogen at a pressure in the range between 101 and 3,550 kPa (0 to 500 psig), this results in a higher C: H ratio of the processed oil, in comparison with processes carried out in the presence of hydrogen at high pressure. This is beneficial for transforming most of the processed oil into carbon black, to the extent that hydrogen leaves the process in the form of water vapor without contributing to product formation. The process eliminates moisture present in the CBFO. In general, CBFO contains approximately <1% moisture. It is known that metallic Na has strong affinity with water and, therefore, reacts with moisture. The present process uses metallic sodium in a concentration between 0.1 and 20% of the CBFO oil concentration, by weight.

In this way, the humidity present in the CBFO is completely eliminated.

In one aspect of the present disclosure, the process is carried out in the presence of hydrogen. The hydrogen added could be in the range of 101 to 3,550 kPa (0 to 500 psig), preferably in the range of 101 to 2,170 kPa (0 to 300 psig), and, more preferably, in the range of 101 to 791 kPa ( 0 to 100 psig). Additionally, hydrogen may not be present in the form of a closed system, that is, without hydrogen pressure or a system without pressure in general. In this way, it could be added in a continuous or semi-continuous flow of hydrogen gas.

The desulfurization process of the present disclosure provides crystalline sodium sulfide as a byproduct. The by-product thus formed is easier to separate and filter and, therefore, results in a better recovery of the desulfurized oil as well as a better separation and processing efficiency of the desulfurized oil.

One of the important aspects of this exhibition is that it provides a process to reduce the size of dispersed sodium - in the form of solid or molten particles such as small droplets. A finer dispersion of metallic sodium increases the efficiency of the desulfurization process. In the conventional process, the by-product, sodium sulfide, tends to cover the surface of metallic sodium thus reducing the efficiency of the process. Therefore, mixing, preferably high shear mixing, is provided for a period of time in the range of 15 minutes to 4 hours at a temperature in the range of 240 to 350 ° C; high shear mixing causes sodium sulfide to break and therefore provides new sodium surfaces to enhance the reaction. Any form of mixing, such as an in-line mixer, a recirculating flow loop, a mechanical mixer, or an ultrasonic mixer, which provides the required amount of dispersion to the metallic sodium can be used.

In the absence of hydrogen, an insoluble sludge formation (unusable material) occurs due to polymerization reactions between desulfurized species.

In addition, pure CBFO has a high viscosity of approximately 1,500 MPa.s (1,500 cP) under ambient conditions. The process of the present exposure results in a desulfurized flow (after the removal of xylene / solvent) that presents a substantial reduction in viscosity in the range of 100 to 150 MPa.s (100 to 150 cP) under ambient conditions. In this way, the total effect is that the desulfurization process is carried out in the absence of hydrogen, and results in a lower loss of contributed oil caused by the formation of insoluble sludge as well as an improvement in the viscosity of the contributed oil, which is further expected to improve the characteristics of the processed carbon black product. In addition, if the process is carried out in the presence of hydrogen, a reduction in the aromatic content of the contribution due to hydrogenation (reduced C: H ratio) may occur, resulting in a lower yield of the carbon black product . Thus, if the process is carried out in the absence of

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hydrogen, the C: H ratio of the treated contribution would increase, thus increasing the yield of the carbon black product. It can be noted that the process of the present exposure can also be extended by means of the desulfurization with Na and organic solvent, together with hydrogen. These results with the simultaneous presence of organic solvent and hydrogen before desulfurization also have benefits in terms of product quality and performance, where the yield of the desulfurized oil is greater than between 15 and 20% compared to the processes. known. Therefore, the scope of our process could be further extended as an improved desulfurization process that involves a simultaneous use of organic solvent and hydrogen, although in an optimized combination (or absence) of each of the reagents.

Another aspect of the process of the present exposure is by-product formation and processing after the desulfurization reaction. The desulfurization of oil provided, using metallic Na, results in the formation of Na2S as a byproduct. However, a large amount of valuable residual CBFO is lost to the extent that it remains associated with this Na2S residue or unreacted sodium, in the form of a highly viscous sludge. The presence of organic solvent in the oil provided before the desulfurization reaction results in the formation of a pure crystalline by-product. This product is easier to separate and filter since there is a substantially lower loss of CBFO. This results in a better recovery of the desulfurized oil, as well as a better separation and processing efficiency after the desulfurization reaction.

The present disclosure uses a high shear mixing apparatus intended to reduce the size of dispersed sodium - in the form of solid or molten particles as small droplets. This provides a finer dispersion of the metallic sodium in the oil provided which increases the desulfurization efficiency of the process. Secondly, during the desulfurization process, the formed by-product tends to cover the surface of metallic sodium, thus reducing efficiency. High shear mixing helps break these surfaces and provide new sodium surfaces to boost the reaction. Any form of mixing, such as an in-line mixer, a recirculating flow loop, a mechanical mixer, or an ultrasonic mixer, which provides the required amount of dispersion to the metallic sodium can be used.

The carbon black manufacturing oil is highly viscous, with a viscosity greater than 1,500 mPa.s (1,500 cP) under ambient conditions. The addition of organic solvent before desulfurization reduces its viscosity by a substantial level (less than 50 mPa.s (50 cP) under ambient conditions, depending on the amount of solvent added), making its transfer and handling easier. , as well as facilitating better mixing and contact with other reagents. Apart from viscosity, the density of CBFO is also high, typically between 1.01 and 1.08 g / cm3. The density of solid sodium at 30 ° C is approximately 0.96 g / cm 3 and the corresponding molten sodium is approximately 0.927 g / cm 3. Therefore, there is a tendency for sodium to remain floating on top of the CBFO surface. Thus, to carry out the reaction, it is necessary to ensure that sodium remains well submerged in the liquid, mainly by means of a continuous stirring mechanism. This can lead to significant safety problems in case the agitation fails or every time the reaction fails. The result will be that all sodium (due to low density) will rise to the top of the contribution and may come into contact with atmospheric humidity. The addition of an adequate amount of organic solvent (for example, xylene, with a density of approximately 0.86 g / cm3), causes the density of the CBFO to be reduced to less than that corresponding to sodium and ensures that all sodium remains well submerged in the liquid contribution at all times.

A process for the removal of residual metallic sodium from the desulfurized oil is also disclosed. During the desulfurization process, metallic sodium disperses finely in the oil. After the desulfurization process is completed, part of the metallic sodium invariably remains in the system either in the form of a suspension or attached to the molecular chain in the oil. The separation or elimination of this sodium from the oil system is remarkably difficult by means of pure mechanical processes. The presence of this residual sodium even in trace amounts has serious implications on the total product quality for the carbon black industry. The process of the present exposure uses acetic acid in the organic solvent mixture. The function of acetic acid is to capture metallic sodium, and the organic solvent promotes a better mixing between the oil raw material and acetic acid. Alternatively, apart from acetic acid, various carboxylic acids, such as formic acid, propanoic acid and mixtures thereof can be used. Additionally, ethanol and alcohols of that type can also be used to capture sodium. Still further, the removal of residual sodium was also achieved by purging the oil with air at elevated temperatures between 30 and 150 ° C. Such treatment is not limited to air alone, and would encompass other gaseous agents, such as oxygen, ozone, and so on.

The exposure will now be described in reference to the following examples which do not limit the scope or scope thereof. The description provided is made for illustrative purposes only.

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Example 1

The experiments were carried out on mixtures of CBFO and xylene of varying proportion, to evaluate the effect of the amount of xylene on the performance of the CBFO. All of the following three examples (listed in TABLE 1) were executed in the presence of hydrogen atmosphere. In example 1, 150 g of CBFO were mixed with 150 ml of xylene. This resulted in the mixture in the form of CBFS: Xylene = 50: 50 (based on weight: volume). The solution was thoroughly mixed and then transferred to a high pressure reactor. 9 g of metallic sodium were weighed separately. Then, the metallic sodium was cut into small pieces of 0.5 to 1.0 cm and added to the CBFS / xylene solution in the reactor. The reactor vessel was first purged with nitrogen to remove air, and then the vessel was purged with hydrogen gas. The reactor was then pressurized to 2,170 kPa (300 psig) with hydrogen. Subsequently, the reactor was heated to a temperature of 290 ° C. The reaction was carried out at this temperature for a period of 4 h. The complete solution was allowed to cool to room temperature and then the CBFO was decanted. The decanted solution was filtered and analyzed in relation to the sulfur content by XRF (X-ray Fluorescence Spectroscopy). Similarly, the desulfurization process was carried out for other variable CBFO ratios: Xylene, specifically, 70:30, 80:20 (as shown in examples 2 and 3 of TABLE 1). The results with respect to these different compositions are tabulated in TABLE 1. The content used of CBFO, xylene and sodium is also tabulated below, together with the desulfurization efficiency for each of the different CBFS ratios: Xylene.

TABLE 1

 Ex.

 Amount of CBFO (g) Amount of Xylene (ml) Ratio of CBFS: Xylene (g: ml) Amount of Na (g) Temp. (° C) Time (h) Desul. (%) Initial Pressure kPa (psig)

 one.

 150 150 50:50 9.0 290 4 86 2,170 (300)

 2.

 210 90 70:30 13.5 290 4 70 2,170 (300)

 3.

 240 60 80:20 15.5 290 4 75 2,170 (300)

It was observed that, in all cases, a desulfurization of more than 70% was obtained.

Viscosity

The sample of Example 2, after desulphurization and distillation of xylene, was analyzed in relation to viscosity as a function of temperature. The sample was initially heated to approximately 175 ° C and viscosity measurements were recorded at different temperatures as the sample cooled. Similarly, measurements were recorded for a second sample of untreated or crude GBFO. The results are tabulated in TABLE 2.

TABLE 2

 serial number

 CBFO-Treated CBOF-Treated Temp

 mPa.s (cP)

 mPa.s (cP)

 one.

 150 ° C 20 14

 2.

 100 ° C 53 23

 3.

 50 ° C 280 70

 Four.

 35 ° C 2,800 120

Thus, it was observed that a substantial reduction in the viscosity of the desulfurized sample was obtained especially in the lower temperature range below 50 ° C. The basic advantages of viscosity reduction could include easier oil processing, and thus a reduction in energy cost as well as an improvement in the quality of the carbon black product due to the formation of finer droplets during the fogging process.

Asphalt Content

The samples were further tested in relation to the asphaltene content of the oil. Asphaltenes are observed to be detrimental to the quality of carbon black as well as to manufacturing processes during the formation of carbon black. Thus, the asphaltene content for treated oil and untreated oil was obtained by determining the insoluble content of n-heptane in the two oils. It was observed that the asphaltene content of the untreated oil was 10.59%. However, the asphaltene content of the treated oil was substantially reduced to 4.65%. This indicated that our process has the ability to reduce the content of asphaltenes by more than 50%.

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Example 2

Successive experiments were carried out to optimize the time, temperature and pressure parameters for the desulfurization process. It was decided that these studies would be carried out on the CBFO: Xylene ratio of 70: 30. These optimization studies are described in examples 4 to 11 listed in TABLE 3.

The following TABLE 3 describes the effect of temperature on desulfurization efficiency. Thus, in each case the ratio of CBFO: Xylene is kept constant at 70: 30. The lot contained 210 g of CBFO and 90 ml of xylene. In each of the samples, 13.5 g of metallic sodium were added. All reagents were placed in the high pressure reactor vessel and then pressurized with hydrogen (approximately 2,170 kPa (300 psig)). The reactions were carried out at a temperature of 290 ° C with different residence time intervals of 3 h, 1 h, 45 min, 30 min and 10 min for examples 4 to 8, respectively. Then, the reactor was cooled, and the CBFO was decanted and analyzed, for each case, by XRF. These desulfurization results are tabulated in TABLE 3. It was observed that the desulfurization efficiency remains practically the same for the residence time spaces of 3 h, 1 h, and 45 min respectively, with an overall desulfurization efficiency of 70%. However, desulfurization efficiency is drastically reduced to 59 and 50% for a reduced residence time of 30 min and 10 min, respectively.

Table 3

 Ex.

 Concentration (CBFO: Xylene) weight vs vol. Amount of Na (g) Time Temperature Hydrogen Pressure% desulfurization

 Four.

 70:30 13.5 3 h 290 ° C 2,710 kPa (300 psig) 70

 5.

 70:30 13.5 1 h 290 ° C 2,710 kPa (300 psig) 70

 6.

 70:30 13.5 45 min 290 ° C 2,710 kPa (300 psig) 68

 7.

 70:30 13.5 30 min 290 ° C 2,710 kPa (300 psig) 59

 8.

 70:30 13.5 10 min 290 ° C 2,710 kPa (300 psig) 50

 9.

 70:30 13.5 1 h 290 ° C 2,710 kPa (300 psig) 10

 10.

 70:30 13.5 1 h 290 ° C 3,550 kPa (500 psig) 70

 eleven.

 70:30 13.5 1 h 290 ° C 791 kPa (100 psig) 62

In addition, desulfurization was carried out at a reduced temperature of 240 ° C, to understand the effect of temperature on desulfurization efficiency. Thus, in example 9, suitable amounts of CBFO mixture: Xylene (70:30) were introduced into the high pressure reactor. 13.5 g of metallic Na were added and the reactor was pressurized with hydrogen at a pressure of approximately 2,170 kPa (300 psig). The reactor was then heated to a temperature of 240 ° C with a residence time of 1 h. The reactor was cooled and the CBFO was decanted and analyzed in relation to the sulfur content. In this case a desulfurization efficiency of 10% was obtained which suggested that the minimum temperature at which an effective desulfurization could be carried out was 240 ° C.

These studies were further expanded to understand the effect of hydrogen partial pressure on desulfurization efficiency.

In examples 10 and 11 different pressures of hydrogen of 3,550 kPa (500 psig) and 791 kPa (100 psig) were maintained. The temperature rose to 290 ° C with a residence time of approximately 1 h. The reactor was cooled and the samples were decanted and analyzed in relation to the sulfur content. It was observed that there was only a marginal improvement in overall desulfurization efficiency with high partial pressures of hydrogen.

Thus, it was observed that the minimum temperature required for the desulfurization reaction was approximately 250 ° C. In addition, it was found that, for optimal desulfurization, a residence time of 1 h was sufficient. It was also observed that the residence time could be reduced further by increasing the sodium content above the stoichiometric value or also by increasing the reaction temperature to above 300 ° C. It was not observed that the effect of hydrogen partial pressure significantly affected desulfurization efficiency.

Example 3

Desulfurization experiments were carried out in the presence and absence of hydrogen and xylene. It was observed that the presence of xylene has a significant impact on the processing as well as the formation of by-products. Similarly, it was important to understand the effect of hydrogen on the total desulfurization process. Thus, in order to study the effect of hydrogen and xylene individually and also in combination, the following schemes were investigated: example 12 - desulfurization in the presence of

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fifteen

twenty

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40

Four. Five

fifty

55

60

xylene and in the absence of H2; example 13 - desulfurization in the presence of xylene and in the presence of H2; Example 14 - desulfurization in the absence of xylene and in the absence of H2.

In the case of example 12, 210 g of CBFO and 90 ml of xylene were introduced into the high pressure reactor. No hydrogen was added to the reactor. For example 13, 210 g of CBFO and 90 ml of xylene were introduced into the high pressure reactor, and approximately 2,170 kPa (300 psig) of hydrogen was added to the reactor. For example 14, 210 g of CBFO were taken and neither xylene and hydrogen was added. In all of examples 12 to 14, a stoichiometric amount of metallic sodium was added. The reaction temperature was maintained at 290 ° C for a residence time of 1 h. Thus, after the reaction, the samples were cooled and decanted for each case. All schemes resulted in free CBFO and sludge (Na2S + CBFO) in varying proportions. The decanted CBFO was weighed; yields are provided in TABLE 4.

Table 4

 Ex.

 Composition Performance of desulfurized CBFO (%)

 12.

 Without H2 + Xylene 72

 13.

 H2 + Xylene 78

 14.

 Without H2 + Without Xylene 54

It was observed that when xylene was used the yield of CBFO was higher compared to when no xylene was added. In addition, to reduce the sodium content of the desulfurized oil, a 5% mixture of acetic acid in xylene was prepared. The acetic acid solution was added to the treated or desulfurized oil. Then, the mixture was heated at 100 ° C for 1 h under vigorous stirring. The mixture was then allowed to cool and filtered. The treatment resulted in a significant reduction of sodium content from 2,000 ppm to <50 ppm. Alternatively, the desulfurized oil treatment can also be achieved by purging the oil with air under elevated temperatures. To do this, 100 ml of desulfurized CBFO was introduced into a glass tube for air treatment and, in this tube, compressed air was continuously purged for a period of 30 minutes. This air reacts with the excess Na present in the oil to form a precipitated mass that can be filtered. It was observed that this treatment resulted in a reduction of the Na content by approximately 50% (from 2,000 ppm to 900 ppm). In addition, to optimize the treatment, the same reaction was carried out at an elevated temperature at 50 ° C. The treatment was found to result in a significant reduction of the Na content by approximately 96% (from 2,200 ppm to 90 ppm).

Experiments were carried out to verify the effect of mixing with a strong shear in which samples were mixed with low agitation mixing (200 to 300 rpm) with an agitator that had blunt-edge blades (made with Teflon / plastic), and samples with higher stirring speeds (700 to 800 rpm) were mixed by mixing in an even reactor with metal blades with relatively sharp edges. It was observed that greater desulfurization was obtained when the agitator had the ability to break up the Na2S particles that are formed and to provide new surfaces of metallic Na in contact with the CBFO to achieve an additional reaction.

Technical advantages

A process for the desulfurization of oil for the manufacture of carbon black, as described in the present exhibition, has several technical advantages that include, but are not limited to, the materialization of: the process does not require hydrogen; the process does not require high pressure conditions; the process reduces the loss of oil provided; the process provides a reduction in the asphaltene content of petroleum oil by> 50%; the process improves the viscosity of the desulfurized oil to <200 mPa.s (cP); the process reduces the residual sodium content to <10 ppm; the process improves the processing and handling conditions of the CBFO; the process provides simple filtration and separation of the desulfurized oil and its by-products; and the process is safe as oil density decreases compared to metallic sodium.

Throughout this specification it will be understood that the word "understand", or variants, such as "comprises" or "comprising", implies the inclusion of an element, integer or stage, or group of elements, integers or stages mentioned, but not the exclusion of any other element, integer or stage, or group of integer elements or stages.

The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, to the extent that the use, in the embodiment of the invention, may be intended to achieve one or more of the desired objectives or results.

Any description of documents, actions, materials, devices, articles or the like that has been included in this specification is merely intended to provide a context for the invention. It should not be considered as an admission that some or all of these subjects are part of the technique

above basic or constituted common general knowledge in the field relevant to the invention because it existed anywhere before the priority date of this application.

The numerical values mentioned for the various quantities, dimensions or physical parameters are only 5 approximations, and it is expected that the values above / below the numerical values assigned to the parameters, dimensions or quantities are within the scope of the exposure, not be that, in the specification, a specific mention of the opposite appears. Whenever a range of values is specified, a value of up to 10% below and above, respectively, the lowest and highest numerical value of the specified range is included in the exposure range.

10

Claims (10)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 1. Process for the desulfurization of petroleum oils, said process comprising the following steps: dilute petroleum oil with an organic hydrocarbon solvent selected from the group consisting of alkanes, alkenes, cyclic alkynes and alkynes, to obtain an oil-solvent mixture, the ratio of the organic solvent to the petroleum oil in the oil-solvent mixture in the range between 50:50 and 20:80, based on the weight in g of petroleum oil and the volume in ml of the organic hydrocarbon solvent in the mixture; transfer the oil-solvent mixture to a reactor vessel; adding solid metallic sodium to the oil-solvent mixture in the reactor vessel, the concentration of sodium being between 0.1 and 20% of the petroleum oil concentration, by weight; react the oil-solvent mixture with sodium at a temperature in the range between 240 and 350 ° C and a pressure in the range between 101 and 3,550 kPa (0 to 500 psig) for 15 minutes to 4 hours under mixing for obtain a resulting mixture; cool and settle the resulting mixture; Y Decant the cooled mixture and filter the decanted solution of desulfurized petroleum oil. 2. The process according to claim 1, wherein the organic hydrocarbon solvent is selected from the group consisting of n-hexane, cyclohexane, heptane, pentene, hexene, heptene, octene, toluene and xylene. 3. Process according to claim 1, which includes the step of purging the reactor vessel with hydrogen gas at a pressure in the range between 101 and 3,550 kPa (0 to 500 psig). 4. Process according to claim 1, which includes the step of separating the organic solvent from the desulfurized petroleum oil by distillation. 5. Process according to claim 1, which includes the step of mixing sodium with the oil-solvent mixture in the reactor vessel using high shear mixing by means of a mixer selected from an in-line mixer, a mechanical mixer, a recirculating pumping loop and an ultrasonic mixer. 6. Process according to claim 1, which includes the step of removing residual metallic sodium by: treatment of the desulfurized petroleum oil with carboxylic acid at between 0.1 and 10% in an organic solvent, by volume, at a temperature in the range between 50 and 150 ° C for 30 minutes to 90 minutes under vigorous stirring; Y filtration of the resulting mixture to obtain desulfurized petroleum oil having a sodium content between 10 and 50 ppm. 7. Process according to claim 6, wherein the carboxylic acid is selected from acetic acid, formic acid and propionic acid. 8. Process according to claim 6, wherein the organic carboxylic acid solvent is selected from alkanes, alkenes, cyclic alkenes, alkynes and alcohol. 9. Process according to claim 6, wherein the organic carboxylic acid solvent is xylene. 10. The process according to claim 1, which includes the step of removing residual metallic sodium by purging the desulfurized petroleum oil with air at a temperature in the range between 30 and 150 ° C.