JPS62250092A - Method for enhancing quality of diesel oil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for upgrading cetane grades of diesel oil. More particularly, the present invention provides a method for improving the cetane grade of diesel fuel while also removing compounds containing heteroaromatic sulfur impurities and selectively removing instability-producing organic compounds from diesel oil. Regarding. Specifically, the present invention involves contacting diesel oil with ozone, nitrogen oxides, nitrous acid, or nitric acid under conditions that enhance the removal of impurities by the solvent in solvent extraction, and using a selected solvent to solvate the diesel oil. By extracting to remove organic impurities and then separating the diesel oil from the solvent used for extraction, the middle distillate containing such impurities is removed.
This invention relates to a method for improving the quality of stillS.

BACKGROUND OF THE INVENTION In the refining of petroleum distillates, removal of sulfur-containing compounds is generally required to meet product specifications. In the past, various methods have been used to remove unwanted sulfur compounds by both chemical treatments and hydrodesulfurization methods. Chemical desulfurization processes are of increasing interest due to the increased reliance on crude oil feedstocks with high sulfur content and the desire to direct hydrogen for use in other refining processes other than hydrodesulfurization processes.

In addition to sulfur content, other important distillate fuel specifications are feedstock dependent. For example, important properties of diesel fuel include ignition quality, oxidative stability, and rum spot carbon in addition to sulfur content. do. Particularly regarding ignition quality, cetane number is a limiting specification for diesel fuel. In order to be suitable for use in automobiles, No. 1
Diesel fuel is generally made from virgin stock with a cetane number of about 45. Railway diesel fuel is similar to diesel fuel for automobiles, but can have a somewhat lower cetane number of about 40.

Many uncracked, i.e., virgin paraffin liquid feedstocks, such as straight-run atmospheric gas oils, have excellent compression ignition properties,
That is, it has a cetane number of about 45 or more. In contrast, thermally or catalytically cracked feedstocks, such as cycle oils, have unsatisfactory ignition properties, ie, cetane numbers below about 35.

In the past, in most countries of the world.

Sufficient quantities of diesel fuel were obtained as stable virgin products from distillation of crude oil. However, as crude oil prices have become higher and crude oil quality has become poorer, the economic viability of refining methods has increased. This has significantly changed the properties of distillate and diesel fuels, particularly in the United States, Canada, and Europe. As heavier crude oils are used, bottoms products are no longer required and the use of effluents from various heavy oil cracking processes as supplementary blending components for central distillate fuels is increasing. I've done it. Decomposition products are generally
It has inferior quality as a fuel (unless hydrocracked) than straight-run products of comparable boiling range. Regarding diesel fuel, the incorporation of cracked products reduced the cetane number, increased aromaticity, and created stability problems in the distillate pool.

The aforementioned changes have continuously lowered the cetane number over a decade. These factors also caused a loss of stability of the distillate fuel, which in turn created problems with the handling and performance characteristics of the diesel fuel. The instability of the central distillate is the result of complex reactions, which are not fully understood, but are believed to be the result of three separate reactions: (1) an acid-base reaction, where organic acids and basic nitrogens react to form precipitates (acid-base salts); (2) oxidizing gum reactions, where alkenes and oxygen react to form gums; and (3) Esterification reactions, where aromatic hydrocarbons, heterocyclic nitrogen, and benzothiol are combined in a multi-step process to form a precipitate.

Higher levels of unsaturated materials have resulted from the increased use of fluid catalytic cracking units and the blending of effluents from thermal processes to meet market demands. A shift to heavier feedstocks and higher severity operations makes sense.

This is because, for example, a major change in the use of FCC could increase the availability of light cycle oils, which are inferior diesel fuel feedstocks.

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The recent emphasis on he-barrel conversion is also expected to increase both nitrogen and sulfur compounds and produce additional distillation products that are not well suited for diesel fuel formulation.

As the demand for central distillates has increased, diesel fuel quality is expected to be further compromised due to deterioration in crude oil quality, reduced demand for bottoms products, and increased use of heavy oil cracking processes.

Recently, treatments to improve distillate quality and stability have been focused on three areas: hydroprocessing, caustic scrubbing, and chemical additives. Although hydroprocessing is effective in improving desulfurization and absorption, it is an expensive method of improving cetane number and stability, requires high capital investment, uses expensive hydrogen and is less expensive than other processing methods. Requires high usage costs.

To reduce the sulfur content of hydrocarbon oils, previous approaches involving high-temperature, high-pressure hydrodesulfurization methods contain a number of major drawbacks; as indicated above, the high-temperature and high-pressure requirements of these methods is very expensive. The hydrogen required for these methods is expensive and requires water for its production. Further processing of the by-products produced, such as hydrogen sulfide and ammonia, which are highly toxic, also
This makes the hydrodesulfurization process expensive. Furthermore, the catalysts used are often inhibited by substances contained in the hydrocarbon oil, making the process even more expensive. All of these factors make known methods economically disadvantageous.

Intense caustic scrubbing removes precipitated precursors such as benzenethiol, sulfur of mercaptans, H2S,
Frequently used to remove acids and phenols from central distillates. Although caustic scrubbing is often effective, it removes little sulfur, does not improve the cetane number, fails to produce stable products in all cases, and removes nitrogen impurities in e.g. virol. Can not do it. The disadvantages of caulking treatment are:
Includes costs of maintaining cauldron strength, disposal of used cauldrons and loss of product due to extraction.

Many types of chemical additives are currently used alone or in combination with other processing techniques to improve the quality of central distillate fuels. Absorption generally provides basicity without first proceeding to an organic acid-base reaction to form a salt. Antioxidants perform the same function that thermally derived distillates do for gasoline. Unsaturations provide free radical precursors that can undergo any of several precipitate-forming reactions, but these reactions are hindered by the presence of antioxidants. however,
Once the sediment begins to form, stability is not as effective and dispersant type additives are used which dissociate the agglomerated sediment particles as well as prevent agglomeration.

Deeper cutting into the barrel
Deeper 1ntobarrel) is currently economically required, and it is desired to blend undecomposed raw materials with catalytically cracked raw materials to produce diesel fuel. Alternative methods to improve quality are currently of particular importance.

In the petroleum industry, petroleum distillates and synfuels (
Solvent extraction has often been used to remove sulfur and/or nitrogen compounds from synfuels, and the extracted oil and solvent are then separated by distillation. However, solvent extraction of petroleum products to remove sulfur generally results in significant oil yield losses and high solvent-to-oil ratios, and provides only limited sulfur removal.

Methods of increasing the cetane number have long been sought in the field, and in general, the cetane properties of fuel compositions containing both aromatic and paraffinic components can be improved by removing the aromatic components, e.g. by solvent extraction. This can be improved by increasing the concentration of paraffin by removing it.

It has long been known that the cetane number of diesel fuels can be improved by the addition of nitrogen-containing fuel additives or by nitrification of nitrogen-containing oxidizers. Diesel range fuel oils with suitable physical properties such as pour point, cloud point, viscosity and volatility can be obtained by nitrogenating the diesel fraction to increase the cetane number. However, such nitrogenization of fuel oils compromises stability by increasing the rum spot carbon content and forming insoluble precipitates that produce clouding and ultimately deposits during storage of the fuel oil. It is well known that there is a tendency to reduce Although many attempts have been made to eliminate the drawbacks of poor stability properties and solvent extraction (including caustic scrubbing) has been applied to improve stability, traditional solvent extraction provide sufficient stability in the case, remove sulfur by
This proved insufficient to achieve high yields without loss of cetane.

The invention described and claimed herein contrasts the commonly used catalytic hydrogenation, caustic scrubbing and chemical additive approaches previously practiced.
The present invention relates to a method for upgrading diesel fuel by removing sulfur-containing organic compounds, increasing cetane grade, and reducing ramsbottom carbon and compounds that cause instability using an extraction/separation approach.

Various methods of processing petroleum fractions by oxidation or extraction are known to upgrade substandard diesel fuel feedstocks while simultaneously removing sulfur, increasing the cetane number of the resulting fuel, and improving stability and stability. No satisfactory method of improving rum spotom carbon has been found.

Nitrogen treatment without extraction using nitric acid was investigated as early as 1893 (as disclosed in U.S. Pat. No. 508.479), and methods involving oxidation of petroleum feedstocks using fumes of nitric acid were No. 542,849, issued in 1895. US Patent No. 522,028 discloses removing sulfur from baking oil by contacting it with oxidizing nitrogen compounds and distilling it in the presence of sulfuric acid. However, this forms carbonaceous deposits in the still and is commercially uneconomical.

Furthermore, U.S. Patent No. 1°864 issued in 1925
．． No. 541 is an organic compound with nitrogen oxide of 400 to 50
It discloses oxidation at 0° C., the contact time is on the order of seconds, and the oxidation is either homogeneous or catalytic using copper and silver catalysts. U.S. Patent No. 1.9
No. 33.748 uses nitrogen oxides to crack petroleum feedstock.
65.6~177℃ (150~35℃)
0) and then using sulfuric acid for extraction, and US Pat. No. 1.935
．． No. 207 discloses a similar process in which improved results are obtained by carrying out the oxidation using nitrogen oxides in the presence of sulfuric acid at temperatures below 30°C. The use of nitric acid and acetic acid followed by sulfuric acid to improve color and odor and remove sulfur from cracked distillate feedstocks is disclosed in US Pat. No. 2,027,648. Although treatment with nitric acid and subsequent sulfuric acid will remove odor and sulfur and improve color, rum spot carbon is satisfactorily reduced using uneconomical levels of sulfuric acid and without reducing cetane number. probably won't. The use of sulfuric acid in combination with air and nitrosyl sulfuric acid to desulfurize petroleum distillates is described in U.S. Patent No. 3.294.67.
It is disclosed in No. 7.

U.S. Pat. No. 2,009,898 describes treating cracked gasoline vapor with nitrogen oxides without significant olefin oxidation and then treating the product with clay to reduce the sulfur content. . However, this method requires the use of uneconomical amounts of clay to meet product specifications. U.S. Patent No. 2.825.744 states that 200℃
A similar process is disclosed in steam at lower temperatures to produce low molecular weight sulfoxides.

U.S. Pat. No. 3,824,342 discloses oxidizing the residue with a number of oxidizing agents including nitrogen oxides and then heat treating to reduce the sulfur content of the residue. , where both steps can be accelerated with catalysts. When applied to diesel fuel, this process produces substantial carbonaceous deposits in the heat treatment furnace and is unsatisfactory for commercial use. A method for deodorizing and desulfurizing light petroleum distillates by treating them with nitrogen oxides, followed by caustic washing and water washing is disclosed in US Pat. No. 3,267,027. This process is unsuitable for producing diesel fuels of acceptable stability and rum spot carbon content.

U.S. Pat. No. 3,163,593 uses a number of distillate gas oxidizers, including nitrogen oxides, to treat vacuum bottoms, bottoms from cracking processes, oil from tar sands, and oil shale. and subsequent pyrolysis at 350-400° C. to produce volatile sulfur compounds and a low sulfur oil. The disclosure of this patent is that alkaline materials such as dolomite or lime can be used to facilitate this process.

The use of air as the oxidizing agent for the pyrolysis bottoms and the use of Group VA and Group VIII metal catalysts together in place of nitrogen oxides, followed by hydrodesulfurization, is disclosed in U.S. Pat. No. 3,341.448. A disclosed advantage of this procedure is a higher degree of desulfurization than would be obtained with hydrotreatment alone under comparable conditions. U.S. Pat. No. 3,244,618 discloses a method for sweetening petroleum hydrocarbons by treating the hydrocarbon fraction with molecular oxygen in the presence of catalytic amounts of nitrogen oxides. Application of this method to diesel fuel results in a product with unacceptable stability and rum spot carbon content.

U.S. Pat. No. 2,004,849 discloses the use of an oxidizing agent, hydrogen perhydrogen, in combination with sulfuric acid to remove sulfur from hydrocarbons without substantial loss of aromatics. There is. However, this method is ineffective in improving the cetane number of diesel fuel and will not increase the yield upon extraction.

Although these methods generally used nitrogen or oxidation treatments to refine or desulfurize the oils, the cetane number of diesel fuels has also been determined, for example, as disclosed in British Patent No. 491.648. It is also known to increase the cetane number by adding "dopes" of derivatives of various nitrogenated hydrocarbons, such as amyl nitrate, octyl nitrate, and nitrate esters. Other nitrogen-containing additives are described in U.S. Pat.
No. 398,505.

Regarding the use of nitrogenation to improve the cetane number of diesel fuel, British Patent No. 491,648 teaches contacting diesel fuel with a nitrogenating agent to increase its cetane number. acetone, methyl alcohol,
Extraction using solvents including ethyl alcohol, ethylene dichloride and aniline has been described to be used to obtain concentrates of nitrogenated petroleum components. However, when diesel fuel is contacted with a nitrogenating agent, the stability decreases and the rum spot carbon increases, and when the disclosed solvent is used to extract the product, the yield of this process decreases and cetane Grade is loss.

U.S. Pat. No. 3,135,680 discloses desulfurizing diesel fuel oil to improve its cetane number by oxidizing it with nitrogen oxides and subsequently washing with water and alkali. However, the resulting products tend to have an unfavorable color resulting from the nitrogen oxide treatment, and subsequent sulfuric acid treatment, vacuum distillation or clay treatment to completely remove the material formed during oxidation can reduce the cetane value. Reduce or eliminate the increase in Because of its rum spot carbon content, the product of this process forms significant coke in the still kettle during distillation. U.S. Pat. No. 3,164.546 discloses the treatment of diesel oil with nitrogen oxides to form an aqueous caulk and/or
A method is described for producing diesel fuel with improved cetane number and odor by washing with solvent extraction followed by water washing. Solvents disclosed as suitable for solvent extraction fixation are nitromethane, dimethylformamide, pyridine, acetonitrile, glycolonitrile, ethylene glycol, ethanolamine and phenol.

However, no mention is made of the critical stability and rum spot carbon content specifications, which are by far the most difficult product specifications when using nitrogen-containing treatment agents.

This method is only exemplified at low cetane number enhancement levels, which is a disadvantage.

Regarding improving product stability by oxidizing petroleum feedstocks, U.S. Pat. Discloses that it will be removed. This process does not increase the cetane grade and the product has the instability characteristics of a nitrated product, which is improved by the extraction process of the present invention. U.S. Patent No. 2,33
No. 3.817 discloses oxidizing diesel fuel oil with nitrogen-containing compounds, then diluting with hexane, and filtering to improve cetane number and prevent sediment formation. Such a product does not pass today's industry standards for stability (but haze formation is reduced) and it does not meet the standards for rum spot carbon.

Techniques involving extraction steps for processing petroleum products without the prior oxidation step required in the present invention are also known for the removal of sulfur impurities. For example, U.S. Pat. No. 2,114,852 discloses heating a hydrocarbon oil or shale with a high boiling point as an impurity to obtain a hydrocarbon fraction, and applying the resulting product to a solvent in the presence of an unsaturated hydrocarbon. Discloses a method comprising extracting with water to remove high boiling sulfur compounds and then oxidizing the extract.

Regarding such solvent extraction, U.S. Patent No. 2,114
, No. 852 discloses that solvents with boiling points no more than 80° C. above the boiling range of the initial hydrocarbon-containing oil mixture are preferred for improving fractionation. I, N. Diyaroff (Diyar.

(1978) disclosed the treatment of diesel fuel with ethylene chlorohydrin mixed with water and
, Neftekhimiya, 16,
(6), pp. 917-920 (1976) compared the use of citric acid and tartaric acid to extract sulfoxide from diesel fuel and found that citric acid was five times more efficient than tartaric acid in extracting sulfoxide. Ta. Aqueous solutions of quaternary ammonium compounds are disclosed in Japanese Patent Application (OPI) No. 74-30401 as being suitable for the treatment of diesel fuel oil. Additionally, U.S. Pat. No. 4,113,607 describes the use of furfural and ferric chloride as effective solvents in reducing nitrogen content in hydrogenated oils, and U.S. Pat. , 749 discloses the use of a complex salt of boron tetrafluoride in a petroleum-immiscible solvent to remove sulfur in oil. U.S. Patent No. 1,971.75
No. 3 relates to the use of solvent extraction to reduce the sulfur content of lubricating oils and uses a mixture of furfural and amylamines.

Either these solvents are not effective in the process according to the invention or the importance and effect of the oxidation step on other product properties is not disclosed. U.S. Patent No. 2,
No. 608,519 uses dimethylformamide (2
5% water) to remove sulfur and aromatics from highly olefinic naphtha without extracting the olefins.

Improvement of cetane number by a solvent extraction method without prior oxidation is disclosed in U.S. Pat. The use of benzo-LuS02 and Clolex solvents to extract aromatics from catalytic cycle feedstocks and thereby improve cetane grade is described. Yields from this process are specifically low, and no yield enhancements are disclosed that can be obtained by combinations of nitrogen-containing oxidizing agents with specific solvents, the specific solvents being
It also modulates other important properties not normally modulated by nitrogen-containing oxidants, such as stability and rum spot carbon.

Selective solvent extraction for removing aromatics from petroleum distillates is well known.

U.S. Pat. No. 3,317,423 uses a dual solvent to furfural-distilled paraffinic hydrocarbons to produce heavy [26
It is disclosed that carbon black feedstock is produced by aromatic extraction at 0° C. + (500° C. +)]. The production of aromatic carbon black feedstocks in a two-step solvent extraction process using furfural, phenol, liquid sulfur dioxide or glycol ether is described in U.S. Pat. No. 3.349.028, in which rum spot carbon is also extracted. U.S. Patent No. 3.415.74
No. 3 uses dimethylformamide (5-18%) in the first step.
discloses the extraction of heavy aromatics and heavy aliphatics from cycle oil in a two-step process using water) and xylene.

U.S. Pat. No. 3,546,108 discloses a furfural/dimethylformamide/water solvent mixture used to extract aromatics from gas oil, and U.S. Pat. No. 2,137,206 discloses The present invention also relates to a method for dewaxing oil using furfural. All of these patents emphasize the importance of pre-solvent extraction treatment and the surprising yield increases obtained thereby or other benefits obtained by the combined use of nitrogen treatment and extraction with selected solvents in the present invention. Not aware of important properties such as stability and rum spot carbon.

U.S. Pat. No. 3,169,998 discloses the selective separation of aromatic hydrocarbons from olefinic hydrocarbons and the olefin hydrocarbonization of mixtures of olefins and saturated hydrocarbons using liquid gamma-butyrolactone as a solvent. Extracting hydrogen is disclosed. Amine sulfonate solvents for the extraction of aromatic feedstocks are described in U.S. Pat.
522.

No. 618.

U.S. Pat. No. 3,539,504 discloses producing central distillate fuels, such as kerosene, with improved combustion and color properties by removing aromatics and olefins by temperature gradient furfural extraction. ing.

Methods of processing petroleum feedstocks by oxidation and subsequent solvent extraction have been described for various purposes. for example,
A method for oxidizing/extracting hydrocarbon-containing oils to produce sulfoxides and sulfones is described in U.S. Patent No. 2.825.74.
No. 4, British Patent No. 442.524, U.S. Patent No. 2,
702,824 and U.S. Patent No. 2.925.442
Disclosed in the issue.

Additionally, U.S. Pat. No. 3,847,800 and U.S. Pat. No. 3,919,402 disclose the use of nitrogen oxides followed by extraction with methanol to remove sulfur and nitrogen compounds from petroleum feedstocks. is listed.

U.S. Pat. No. 4,485,007 discloses a method for refining hydrocarbon oils, such as shale oil, containing both heteroatomic sulfur compounds and heteroatomic nitrogen compounds, in which First, a hydrocarbon oil is reacted with an oxidizing gas containing nitrogen oxides, and at the same time, the molar ratio of nitrogen oxides to total sulfur heteroatoms and nitrogen heteroatoms is limited, and the gaseous sulfur to sulfur heteroatoms is limiting the conversion to oxides to no more than about 60% by weight and then extracting the oxidized oil in one step with an amine selected from the group consisting of ethylenediamine, monoethanolamine, jetanolamine and mixtures thereof; A second extraction step is then carried out with formic acid as an extraction. The amine extraction solvent acts to remove sulfur compounds, and the formic acid extraction solvent acts to remove nitrogen impurities.

Oxidation of hydrocarbon oils with aqueous nitric acid followed by acetone, methyl ethyl ketone, cyclohexanone, methanol, ethanol, normal propatool, impropatol, ethyl acetate, tetrahydrofuran, dioxane, or combinations of alcohols and ketones, alcohols and water, ketones and water , or by extraction with a combination of alcohols.
Disclosed in US Pat. No. 4,280,818.

The methods described above have had some success in desulfurizing petroleum fuels, but the oxidation removes some of the original sulfur content as gaseous sulfur oxides and converts some of the original sulfur content into sulfoxides and/or The known approach of conversion to sulfone and subsequent extraction with a suitable solvent to obtain the desired raffinate with low sulfur content did not completely eliminate the problem.

Similarly, direct extraction of a hydrocarbon oil with a selected solvent to remove sulfur and nitrogen impurities to produce a raffinate with a low sulfur content reduces the sulfur content of the hydrocarbon oil, but does not reduce the sulfur content of the hydrocarbon oil as desired. produces uneconomically low yields of raffinate.

The aforementioned method basically has a first-order drawback = (a)
The selected solvents are only suitable for certain selected oils:
(b) the solvent produces low extraction yields or does not provide sufficient phase separation to enable solvent extraction; (
c) require unacceptably high solvent-to-oil ratios, reducing acceptance rates and making these methods uneconomical;
(d) they require expensive catalysts or extremely harsh oxidation conditions to adequately remove sulfur; and (e) oxidative desulfurization methods involving nitrogen-containing oxidants Increases gum and sediment and reduces the stability of the fuel produced.

For these reasons, current techniques for sulfur removal, including oxidation and subsequent extraction of hydrocarbon oils, require significant improvement.

Similarly, conventional methods of improving the cetane number of diesel oil by oxidizing with nitrogen-containing oxidizing agents are inadequate for meeting other product specifications. In particular, diesel fuels produced by nitrogen-containing oxidant oxidation and solvent extraction do not meet the sulfur and cetane requirements for fuels in some cases, but do meet the important requirements of yield, stability, and the rum spot carbon content. I am unsatisfied with the standards. Methods using sulfuric acid in conjunction with nitrogen-containing oxidizers are ineffective for maintaining high cetane ratings. The distillation method is not commercially viable due to the presence of significant carbonaceous precipitates in the still, and when heat treatment is applied to diesel fuel to reduce the sulfur content of the bottom liquor, this method also Forms considerable carbonaceous deposits in the tank.

Traditional oxidative cetane enhancement methods, in addition to being unable to produce diesel fuel with sufficient stability and rum spot carbon content, use solvents that, like oxidative desulfurization methods, give poor yields. however, it requires an unacceptably high solvent-to-oil ratio. Alternatively, the solvents used in some prior art methods reduce or completely eliminate the cetane number improvement benefits obtained by oxidation.

Especially because of the various sulfur-containing compounds and compounds that cause instability present in petroleum hydrocarbon feedstocks, and especially because of the selectivity of the solvent for sulfur-containing compounds, nitrogen-containing compounds, aromatics and olefinic compounds. Previous attempts to upgrade central distillate fuels by oxidation, solvent extraction, or a combination of the two have focused on at most one or two product properties, and have focused on acceptable sulfur content or ignition. In order to obtain a product with properties, generally required product yield and stability were sacrificed.

Many diesel fuels with low cetane ratings and high sulfur content meet stability and rum spot carbon specifications, but these fuels can be oxidized to improve the cetane rating or
Alternatively, if the sulfur is reduced, the rum spot carbon and stability become unacceptable.

SUMMARY OF THE INVENTION One object of the present invention is a method of improving the cetane number of diesel oil without reducing stability or increasing rum spot carbon content.

A second object of the present invention is a method for upgrading diesel oil by reducing its sulfur content and improving its stability.

Another object of the invention is a method for upgrading diesel oil using solvent extraction with high solvent extraction efficiency and correspondingly high yield.

An additional object of the present invention is a method for producing a blended diesel fuel that meets industry specifications for cetane number, sulfur content, rum spot carbon, product stability, and pour point from off-spec diesel oil.

Diesel oil can be improved by first contacting the diesel oil with an oxidizing agent selected from the group consisting of ozone, gaseous nitrogen oxides, nitric acid and nitrous acid, and then by selective solvent extraction, and It has now been discovered that diesel fuel can be produced from feedstock or blended feedstock. The process according to the invention makes it possible to simultaneously desulphurize and improve the cetane number of diesel fuels, significantly improving the storage stability and increasing the handling properties.

Accordingly, one embodiment of the invention provides: (a) Derived from a petroleum source, from about 149°C to about 3°C at normal pressure.
Diesel oil having a boiling point of between about 300"F and 700°C is reacted with an oxidizing agent selected from the group consisting of a nitrogen-containing oxidizing agent and ozone, wherein (1) the reaction is in step (a) (2) (i) the reaction is sufficient to increase the cetane number of the diesel oil obtained in step (a) by at least 5 cetane numbers over the cetane number of the diesel oil feed to step (a); when the agent is a nitrogen-containing oxidizing agent, the amount of oxidizing agent equal to a 100% nitric acid basis is such that no more than about 10% by weight of the diesel oil feed; When the agent is ozone, the amount of oxidizing agent is sufficient to reduce the sulfur content of the reacted diesel oil obtained in step (a) by about 10% or more than the diesel oil feed to step CFL). (b) the diesel oil from step (a) above is extracted with a solvent, said extraction solvent (1) having a dipole moment of about 2 or more; and (2) obtained in step (a). a mixture of solvents that is substantially immiscible with diesel oil at the temperature of contact with the diesel oil, (3) is a non-halogenated solvent, and (4) excludes amines that are reactive with oxidizing agents. or contacting with a mixture of the solvent and water such that the solvent contains about 50% by weight or less of water;
and (c) separating the diesel oil from step (b) above from the extraction solvent to recover the improved diesel fuel. How to make improved diesel fuel
provide.

Other embodiments of the invention include: (a) derived from a petroleum source, from about 149°C to about 3°C at normal pressure;
(about 300°F to 700°F) is reacted with an oxidizing agent selected from the group consisting of a nitrogen-containing oxidizing agent and ozone, wherein (1) the reaction is (2)(i) is sufficient to increase the cetane number of the diesel oil obtained in step (a) by at least 5 cetane numbers over the cetane number of the diesel oil feed to step (a); The reaction is carried out in an amount equal to 100% nitric acid standard when the oxidizing agent is a nitrogen-containing oxidizing agent.
(i) the reaction is such that the amount of oxidizer is less than about 10% by weight of the diesel oil feed to step (a), and (i) the reaction is such that the amount of oxidant is less than about 10% by weight of the diesel oil feed to step The process (than the oil feed)
a) is sufficient to reduce the sulfur content of the reacted diesel oil obtained in step (a) by about 10% or more; and (b) the diesel oil from step (a) above is treated with an extraction solvent, said extraction solvent. (1) has a dipole moment of about 2 or more; (2) is substantially immiscible with diesel oil at the temperature of contact with the diesel oil obtained in step (a); and (3) is non-halogen. (4) eliminates amines that are reactive with oxidizing agents, and (5) eliminates the following functional groups: -S=O, -C-N-1-S-1-C-NO2 and −
〇-0-, containing at least one of the following: a mixture of the solvents or a mixture of the solvent and water such that the solvent contains about 50% by weight or less of water;
and (c) separating the diesel oil from step (b) above from the extraction solvent to recover an improved diesel fuel. ,provide.

Other embodiments of the present invention provide for the step of: (a) being derived from a petroleum source from about 149<0>C to about 3<0>C at normal pressure;
Diesel oil having a boiling point of between about 300"F and 700"F is reacted with an oxidizing agent selected from the group consisting of a nitrogen-containing oxidizing agent and ozone, wherein (1) the reaction occurs in step (a). (2) (i) the reaction is sufficient to increase the cetane number of the diesel oil obtained in step (a) by at least 5 cetane numbers over the cetane number of the diesel oil feed to step (a); When the oxidizing agent is a nitrogen-containing oxidizing agent, an amount of oxidizing agent equal to a 100% nitric acid basis is added to the process (
(i) the reaction is such that the amount of oxidizer is less than about 10% by weight of the diesel oil feed to step (a), and (i) the reaction is such that the amount of oxidant is less than about 10% by weight of the diesel oil feed to step The process (than the oil feed)
a) which is sufficient to reduce the sulfur content of the reacted diesel oil obtained in step (a) by more than about 10%; (b) the diesel oil from step (a) above;
Furfural, butyrolactone, dimethylformamide, methylcarpitol, tetrahydrofurfuryl alcohol, dimethyl sulfoxide, sulfolane, sulfolene, dimethylacetamide, 1-methyl-2-pyrrolidone,
(c) contacting with an extraction solvent selected from the group consisting of acetonitrile, acetic anhydride, nitrobenzene, nitromethane and mixtures thereof, or mixtures thereof with water containing up to 50% by weight of water; b) separating the diesel oil from the extraction solvent to recover an improved diesel fuel.

As indicated above, the present invention is suitable for use in temperatures ranging from about 149°C to about 37°C at normal pressure, including those containing heteroatomic sulfur compounds.
A petroleum-derived diesel fuel oil having a boiling point of 1°C (approximately 300-700°C) is upgraded to reduce the cetane number of the reacted product of step (a) by at least as low as that of the diesel oil feed to step (b). Provides a method for increasing the stability by about 5 while at the same time meeting stability requirements. The method of the invention is applicable to the upgrading of diesel oils, common petroleum crudes or crude oil fractions containing sulfur, aromatics, olefinic and naphthenic compounds as impurities, which may be derived from any source. The term “diesel oil” used here
sel oil) J is a petroleum-derived oil with a nominal temperature of 149°C to about 371°C (about 30°C) that can be improved by the method of the present invention.
Defined broadly to include any hydrocarbon with a boiling point range of 0 to 700 g, and the term "diesel fuel" is generally used to describe the upgraded product, These terms may be used interchangeably. Preferred petroleum sources of diesel oil that can be used in the present invention are those containing less than about 40% aromatics, less than about 35% olefins by weight. and those containing less than about 40 weight percent aromatics and less than about 35 weight percent olefins.

The method of the present invention is essentially not limited by the diesel oil source and can be applied to any diesel oil with an upper boiling point range from petroleum sources, including ordinary crude oil, heavy crude oil and tar sands. can.

In the method for upgrading diesel oil according to the invention, the specific product specifications can be varied within wide limits. The disclosure provided herein shows that the process of the invention can be easily applied by those skilled in the art and modified by formulation to have specific desired specifications, particularly with respect to cetane, sulfur content, rum spot carbon and stability, density and boiling range. Diesel fuel can be produced. Furthermore, the method of the present invention may optionally be performed using conventional techniques to meet product specifications, such as chemical additives, such as corrosion inhibitors,
It can be used in combination with the addition of stabilizers and the like.

Fuel stability is determined by a number of accelerated tests, one of which is the Nalco 149°C (300°
F) It is a test. For satisfactory stability in commercial storage and use, transportation fuels must exhibit a Nalco rating of about 7.0 or less, about 7.0
The grade is an acceptable upper limit for commercial use, but lower levels are desirable. Applicable Narco (
The Na 1 co) test is well known in the art and can be easily performed, for example, as follows. 50ml of the oil to be tested with a diameter of 3cm
tube and place this tube in a bath at 149°C (300°C) for 90 minutes.
Heat for 0 minutes and then cool the oil. The oil is then filtered through a microporous filter using No. 1 filter paper, the filter paper and filter are washed with heptane, and the remaining liquid is used as a standard sample. to determine the stability grade.

Desulfurization is a second generally important aspect of diesel oil refining or upgrading. Sulfur compounds present as impurities can include, for example, thiophene sulfur, mercaptan sulfur, sulfides, thiols, and disulfides. The selection of suitable solvents for desulfurization is important because the selectivity of various solvents in the extraction of compounds with different sulfur-containing impurities, which can be increased or decreased by oxidation, differs depending on the specific solvent and feed characteristics. is experimental;
And selection cannot generally be based on theory.

Cetane number is an important quality characteristic of diesel fuel, but the enhancement of cetane number obtained by oxidation is poorly understood. In particular, it is known that an increase in nitrogen in the oxidizing agent is related to an increase in cetane number, and extraction of aromatic substances is known to contribute to improving cetane number, but nitrogen in raffinate is associated with an increase in cetane number. ozone-like in the present invention does not correlate well with the cetane number improvement and aromatic removal alone cannot explain the cetane number response obtained in the high yields observed in the present invention. Oxidation using a nitrogen-uncombined oxidizing agent containing an oxidizing agent increases the cetane number, although no nitrogen is added by the oxidizing agent.

In addition to controlling the above criteria for stability, sulfur content, and cetane number, rum spot carbon content is important for diesel fuel.
There are two important quality characteristics. This is because fuels high in rum spot carbon create fouling problems when used in diesel engines. In acceptable diesel fuels, the rum spot carbon content is
D 524, preferably less than about 0.3% by weight.

Without wishing to be bound by theory, the complex process according to the present invention to upgrade diesel oil by oxidation and extraction involves the addition of nitrogen to paraffins, olefins, naphthenes, esters, amines, azides, indoles, etc. It is currently believed to include the formation of amines, azides, indoles, etc. Selection of a suitable extraction solvent with high selectivity for compounds formed on oxidation allows selective removal of cetane-neutral or cetane-lowering compounds in the extraction. Furthermore, sulfur-containing compounds and compounds that cause instability can be extracted simultaneously by selecting appropriate solvents. The selection of a suitable solvent is important and is made difficult by circumstances in which solvents capable of extracting some of the aforementioned compounds are nevertheless ineffective in the present invention for the following reasons: (a) Solvents does not appreciably remove sulfur; (b) removes so much nitrogen that it improves stability, resulting in an undesirable reduction in cetane number; (c) does not remove nitrogen and is acceptable. produces a cetane number but makes the stability and rum spot carbon unacceptable; or (d
) lower yield.

Typically, the method of the invention can be used with atmospheric gas oils or cycle oils. Atmospheric gas oil is a distillate derived from petroleum crude oil sources.

Atmospheric gas oil is used in diesel oil formulations
component and may contain substandard sulfur content for use as diesel fuel. Typically, sulfur as a heteroatom is present as thiols, disulfides, sulfides, thiophenes, mercaptans, and nitrogen as substituted pyridines and pyrroles,
and other compounds. A typical analysis of diesel oil that can be used in the present invention is set forth in Table 1 below.

FIG. 1 schematically depicts one embodiment of the process of the invention, in which diesel oil feed l and nitric acid passing through inlet 2 are mixed and entered into reactor 3.

After reaction in the reactor, the oxidized product 4 can be separated from the by-product bottoms 5 and placed in a solvent extractor 6 where it is brought into contact with the extraction solvent 7 and the solvent/oxidation Extraction phase 8 containing a solvent that separates the oil and has impurities
After removing the residual solvent, the oxidized raffinate phase 9 containing the residual solvent is placed in a recovery vessel IO to remove the residual solvent 11 and obtain an improved diesel fuel 12 according to the present invention.

In the first step of the process of the invention, a diesel oil, for example an atmospheric gas oil fraction, is reacted by contact with an oxidizing agent. If necessary, the feed oil may first be pretreated, e.g.
The oil is washed to remove phenols or other corrosive components, filtered to remove gums or sediment, heated or treated with commonly used H2SO4. In the first step of the invention, the oxidizing agent can be a nitrogen-containing oxidizing agent or an oxidizing agent other than a nitrogen-containing oxidizing agent, such as ozone. The term “nitrogen-containing oxidizing agent”
oxidizing agent) J is here defined as an oxidizing gas containing at least one nitrogen-containing oxidizing compound, for example a nitrogen oxide having more than one oxygen atom for each nitrogen atom; Used to mean oxidizing liquids containing at least one of the nitrogen oxides having more than 3 oxygen atoms, nitrous acid and nitric acid.

The oxidizing gas used can be a gas containing only one such nitrogen oxide, or it can contain a mixture of such nitrogen oxides. Additionally, oxidizing gases.

those that also contain other components, such as oxygen, nitrogen, lower nitrogen oxides, i.e. 1 per nitrogen atom in the oxide.
For efficiency, the oxidizing gas is preferably a nitrogen oxide containing only one oxygen atom or less than one oxygen atom.
may contain only nitrogen oxides with more than 3 oxygen atoms, but require mixtures with other gases, such as oxygen, nitrogen, and inert gases, such as air, helium, and helium and air. It can be used according to your needs. Suitably, the oxidizing gas contains 2 to each nitrogen atom.
contain at least one nitrogen oxide having more than one oxygen atom in a proportion of at least 0.5% by volume, but its use may be reduced if the flow rate of the oxidizing agent is increased over a longer period of time. can do. Nitrogen dioxide or its dimer N2O4 can advantageously be used alone or in the form of a mixture with air.

The nitrogen-containing oxidizing liquid used can be a liquid nitrogen oxide, nitrous acid, or nitric acid as defined above, in the form of a concentrated acid or a mixture with about 0-90% by weight water. be able to. Preferably, the liquid nitrogen-containing oxidizing agent is an aqueous solution of nitric acid containing about 50-90% by weight nitric acid.

When using nitric acid as the nitrogen-containing oxidizing agent in the present invention, it may be advantageous to use it in combination with other organic or inorganic acids. Suitable inorganic acids include sulfuric acid and phosphoric acid, and suitable organic acids include, for example:
Includes acetic acid and formic acid. Organic acids and inorganic acids can be used alone or in combination. Typically, the inorganic acid can be added to the aqueous nitric acid solution used as an oxidizing agent in an amount of about 5 to 200% by weight of the aqueous nitric acid solution, and the organic acid can be added in an amount of about 5 to 200% by weight of the aqueous nitric acid solution. It can be added with. Preferred combinations of nitric acid and auxiliary acids include nitric acid and sulfuric acid, nitric acid and acetic acid, and nitric acid and formic acid.

When ozone is used as an oxidizing agent in the present invention, it is typically used as an oxidizing gas containing ozone alone or in a mixture, said mixture containing other components such as oxygen, nitrogen, as well as inert gases. 1, for example, containing helium or helium and air. Suitably, the oxidizing gas will contain at least about 1% ozone by volume. If desired, ozone can be used in the method according to the invention in combination with the aforementioned nitrogen-containing oxidizing agents.

In the first step of the process of the invention, diesel oil, for example atmospheric gas oil, is reacted with an oxidizing agent in liquid or gaseous form. The contacting of the diesel oil with the oxidizing agent as a liquid may be carried out by means conventional in the art of contacting two liquid reactants, for example by injecting the oxidizing agent below the surface of the agitated oil in the reactor. This can be achieved by When using the oxidizing agent as a gas, the oxidizing agent gas can be contacted with the diesel oil using conventional means of contacting gaseous and liquid reaction components. Suitable examples of such means of contacting gaseous and liquid reactants include dispersing the gas as bubbles in the liquid, countercurrently or cocurrently with the flow of the liquid, using an inert The latter type of flow is preferred, involving trickling liquid onto a bed of solids with the gas passing over the bed.

In the first step of the process of the invention, the operating parameters during the reaction of diesel oil with the oxidizing agent are adjusted to ensure sufficient reaction to improve the cetane number and to eliminate sulfur compound-containing impurities and instability. It is important to improve the efficiency of extraction in the second step of impurities due to However, this reaction step should be very limited so that no adverse effects occur on the diesel oil substrate ultimately obtained and recovered after the upgrading method of the present invention.

These important process adjustments for the reaction of diesel oil and oxidizer are detailed below.

As used herein, the term "acid to oil ratio" (acid to oil nitric acid, A10) refers to a water-free acid (or N02 or N2O4
When using a nitrogen-containing oxidizing agent, such as 100% concentration of nitric acid (based on 100% concentration of nitric acid (based on nitrogen equivalent weight) to the weight of the diesel oil feedstock), and from about o,ooot to about 0.
1, preferably from about o,oos to about 0.05. Control of the treatment with a nitrogen-containing oxidizing agent in the first step of the process of the invention can be achieved by controlling the moisture content of the acid used in the reactor. Treatment with a nitrogen-containing oxidizing agent in the first step can also be adjusted and improved by the simultaneous presence of sulfuric acid or other auxiliary acids mixed with the oxidizing agent. When ozone is used as the oxidizing agent, the amount of ozone increases the sulfur content of the reacted diesel oil obtained in step (b) by about 10% or more, preferably about 5% more than the diesel oil feed to step (a).
This amount is sufficient to reduce the amount to 0%.

This adjustment of the amount of nitrogen-containing oxidizer or ozone to the total amount of diesel oil feed can be easily maintained.

As a result of adjusting the parameters of step (a) of the process of the invention, the cetane number of the reacted diesel oil is increased by at least about 5 over the diesel oil feed to step (a).

For example, determining the amount of oxidant by knowing the concentration of oxidizer/ozone containing nitrogen and knowing the sulfur heterolayer content and cetane number of the feed obtained using common chemical analysis. Can be done.

Conventional means of metering gaseous and liquid reaction components can be used.

The reaction in the first step of the method of the present invention is carried out at a temperature of about -40°C to about 20°C.
Can be carried out at any temperature from 0°C, but preferably below about 90°C, most preferably from about 25 to 90°C.
It will be carried out in The reaction time is not particularly limited, but includes any time period from about 1 minute to about 3 weeks, for example. The first step of the present invention can be carried out at atmospheric pressure, or at higher or lower pressures, if desired. Advantageously, this reaction step is carried out using conventional stirring means, e.g.
It is carried out using a stirrer. In the method of the invention,
Step (a) above is carried out to such an extent that an increase of at least 5 cetane numbers, generally 7 cetane numbers, and more usually 9 cetane numbers is achieved over the diesel oil feed to step (a).

When a nitrogen-containing oxidizing agent is used in the first step of the invention, the content of nitrogen compounds will typically be increased compared to that originally in the diesel oil. Without wishing to be bound by theory, it is believed that the reason for the increase in the content of nitrogen compounds is that nitrogenization of the diesel oil substrate occurs, resulting in an increase in the content of compounds of heteroatomic nitrogen.

A contact time of less than about 120 hours and a contact time of less than about 0. A weight ratio of nitrogen-containing oxidant to total feed of less than 1 is desirable not only from an efficiency standpoint, but also from an economic standpoint. In particular, the combination of a contact time of about 30 minutes and a nitrogen-containing oxidizer to diesel oil weight ratio of about 0.05 or less can be advantageously used to produce diesel oils with reduced sulfur content and improved stability. It can be obtained in the highest yield.

However, due to the known relationship between nitrogen-containing oxidizers and cetane number, when using nitrogen-containing oxidizers, careful control of the minimum amount of nitrogen compounds added to the diesel oil feed will reduce the It is also advantageous to have a sufficient cetane number in the diesel fuel used.

In order to improve the rum spot carbon and stability while retaining a high cetane number in the process of the present invention, the preferred level of nitrogen in the diesel oil after the first step of contacting the diesel oil with a nitrogen-containing oxidizer is Approximately 1500~
2000 ppm nitrogen. If necessary, the diesel oil can be subjected to separation steps, such as decantation, alkaline treatment, water washing or clay treatment.

The diesel oil that has been subjected to the reaction described above for step (a) of the process of the invention is then subjected to an extraction step (b) using a suitable extraction solvent. As will be seen from the Examples described hereinafter, the process conditions described for reaction step (a) above may be adjusted to ensure that the particular selected extraction solvent used in extraction step (b) of the process of the invention is , increases the extraction removal of sulfur-containing impurities, instability-causing compounds, rum spot carbon, and cetane-reducing compounds naturally present in the diesel oil to be upgraded, thereby increasing the amount of sulfur-containing impurities, instability-causing compounds, rum spot carbon, and cetane-reducing compounds that are recovered and upgraded as a result of the process of the present invention. Improves the ability of ultimate diesel oil to reduce those levels.

In the extraction step (b) of the method of the invention, the diesel oil obtained from step (a) of the method of the invention is extracted with an extraction solvent,
wherein the extraction solvent (a) has a dipole moment of about 2 or greater; and (b) is substantially immiscible with the diesel oil at the temperature of contact with the diesel oil obtained in step (a). (e) is a non-halogenated solvent; and (d) excludes amines that are reactive with oxidizing agents. Contact with a mixture of the species or species and water. The term "dipole moment" as used in the present invention means a dipole moment measured in benzene at 25° C. and having a dipole moment of 2 or more, more preferably 3 or more, and with other characteristics as mentioned above. It is believed that virtually all solvents having a .

In particular, suitable extraction solvents having the aforementioned properties with respect to dipole moment, immiscibility, non-halogenation and non-reactivity with oxidizing agents include solvents having the following functional groups within them: OOO -S= O1-C-N-1-S-1-C-NO2 and -
Examples of immiscible, non-halogenated organic solvents that have a dipole moment of 2.0 or greater and exclude oxidant-reactive amine solvents and are useful in the present invention are listed in Table 2 below. .

Person name 25°C, dipolar monomer in benzene Gamma-butyrolactone 4.00 Furfural 3.60 Dimethylformamide (DMF) 3,86 Acetic anhydride 3.15 Dimethyl sulfoxide (DM 30) 3.90 Sulfolane 4.701- Methyl-2-
pyrrolidone
4.09 Acetonitrile 3.40
Nitromethane 3.13 Tetrahydrofurfuryl Alcohol 2.12 (Pure) In contrast, commonly used extraction solvents with a dipole moment of less than about 2 are unsuitable for use in step (b) of the present invention. Examples of these solvents are listed in Table 3 below: 1 Dipole monomer in benzene at 25°C Formic acid (88% aqueous solution) 1.20 Acetic acid
1.60 methanol
1.70 ethanol
1.75 ethylene glycol 1.
50 Phenol 1.45 Diethylamine 1.17 Aniline
1.55 Hexamethylenediamine (70% aqueous solution) 1.94 Ethylenediamine 1.92 In particular, those of the present invention which have the required dipole moment and immiscibility and which are halogenated and are not amines. Solvents useful in extraction step (b) of the process include furfural, butyrolactone, dimethylformamide, methylcarpitol, tetrafurfural alcohol, dimethyl sulfoxide, sulfolane, sulfolene, acetic anhydride, dimethylacetamide, acetonitrile, 1-methyl- Includes 2-pyrrolidone, nitrobenzene and nitromethane. These extraction solvents can be used alone or in combination, and each of the extraction solvents used can be used alone or in combination with one or more of the aforementioned solvents containing up to about 50% by weight of water. It can be used in the form of a mixture of water and water. Water in combination with these extraction solvents can be advantageously used to increase the phase separation and yield of oil recovered in extraction step (b). The amount of water that can be used with a particular extraction solvent is suitably determined by performing routine screening tests to independently It is possible to determine the type of extraction solvent to be used or in admixture with water and the degree of admixture with water that can be advantageously used. These routine screening tests simply measure the yield determined by routine screening tests to determine which extraction solvent or water/water mixture can be advantageously used with a given diesel oil feed. %, sulfur content present, stability and cetane number.

In the extraction step (b) of the present invention, a fuu extraction procedure is used. Generally, the extraction solvent is simply added to and mixed with the diesel oil being treated in step (a). The length of time for contacting the extraction solvent allows for the simple mass transfer of sulfur-containing compound impurities, compound impurities that create instability, or rum spot carbon-containing components from the diesel oil phase into the extraction solvent phase. This is the only amount of time required to do so, and is typically about 1 to 30 minutes. Generally, suitable extraction times are about 1 to 30 minutes.

The temperature of the extraction process is adjustable over a wide range;
For example, about 4.4°C to about 149°C (about 406F
~300”F), preferably at room temperature, e.g.
to about 32° C. (about 70 degrees Celsius to about 90 degrees Celsius). The solvent can be added in substantially pure form, for example, as obtained directly from a commercial source, or as a recovered and purified used solvent, or as a solvent enriched in a recycle stream. There may be a deficiency in the amount of solvent desired for extraction, which is replenished by the addition of additional solvent. Although the invention is illustrated in examples using a single solvent extraction step, the solvent extraction step (b) may be varied as necessary, e.g. in time, temperature, or solvent to oil ratio. It can be carried out in a sequence of separate solvent extraction zones.

It should be appreciated that in extraction step (b) of the present invention, the extraction solvent is immiscible with diesel oil and is not halogenated. Thus, the lack of miscibility facilitates phase separation after completion of the extraction. Once an emulsion is formed, it can be easily broken due to phase separation, for example by heating. Furthermore, oxidant-reactive amine solvents are not used as extraction solvents in extraction step (b) of the process of the invention.

The extraction step (b) of the method of the invention is generally carried out as follows. Simply add the extraction solvent to the diesel oil, mix the extraction solvent with the diesel oil, allow this mixture to undergo phase separation, and then add the extraction solvent phase containing the sulfur oxidation fraction or the impurities causing instability to the diesel oil. Separates from the oil matrix phase. Extraction in extraction step (b) of the method of the invention can be accomplished using common chemical engineering techniques.

Generally, a suitable extraction solvent to oil weight ratio (S10) is about 0.
．． 05:1 to about 5=1, preferably about 0.1:1 to about 0
．． These ratios are not considered limiting, although they can be in the range of 5:1.

In a preferred embodiment of the invention, the solvent extraction step (b
The solvent to oil ratio in ) is reduced to a much lower value than previously used, increasing the efficiency of the reaction/extraction process of the present invention. As shown in Figure 2, the efficiency of solvent extraction of sulfur impurities can be improved by increasing the solvent to oil ratio even when not reacted with an oxidizing agent. FIG. 2 shows the results of extraction of the atmospheric gas oil of Table 1 with gamma-butyrolactone. Unreacted atmospheric gas oil (
AGO), the solvent to oil weight ratio (S10) is 1.
At 0:1, the raffinate had a yield of 91% by weight, but the sulfur reduction rate was only 22% (0.93%).
The removal rate of sulfur was approximately 60% (0.4% S).
8% S) was achieved using a very high S10 ratio of 9.0:1, but the oil yield was very low (only 7%
6%), thus a higher S10 ratio in the extraction solvent involves higher costs for solvent recovery as well as greater oil losses, which makes solvent extraction of hydrocarbons such as diesel oil uneconomical. This is one factor.

As seen in Figure 3, which shows the effect of the reaction of atmospheric gas oil in Table 1 on gamma-butyrolactone extraction, an increase in the solvent-to-oil ratio increases the oil yield, even using reacted oil. decrease. However, the loss in oil yield can be offset by the severity of the reaction. Thus, 55% sulfur removal by extraction is approximately 6.0:1 S for unreacted oil.
10 ratio, 1.0= for mildly reacted AGO
S10 ratios greater than 1 and S10 ratios less than 1.0:1 for moderately harshly reacted AGO and S10 less than 0.5:1 for severely reacted AGOs.
The severity of the reaction is expressed by the sulfur content remaining after the reaction. When the sulfur loss is greater than about 50%, the oil is "severerly"
reacted)J. In each case, decreasing the solvent-to-oil ratio is accompanied by a significant increase in oil yield, i.e., from approximately 75% extracted oil yield for unreacted oil to approximately 75% for heavily reacted oil. The oil yield increases to greater than 90%. Accordingly, one aspect of the invention is:
A surprisingly low solvent-to-oil ratio is required to obtain the desired sulfur reduction for the reacted feedstock as opposed to the unreacted feedstock.

As the severity of the reaction in the first step of the invention increases, the cetane number increases and the sulfur decreases, but the stability decreases and
And the ram spot carbon increases undesirably. Extraction in the second step of the invention further reduces sulfur content while significantly improving stability and rum spot carbon. The degree of stability and lamb spot carbon improvement obtained is directly related to the solvent to oil ratio used in the extraction.

In general, even mild treatments with nitric acid or ozone will significantly degrade the stability and rum spot carbon. For example, a 90% nitric acid to oil weight ratio of only 0.0025 will increase rum spot carbon to a level above 1.5% and degrade Nalco stability to about 20.

Solvent extraction with the solvents of the present invention provides stability and lamb spot carbon to commercially acceptable standards, while at the same time
It can be used to remove sulfur, retain cetane, and achieve high raffinate yields. In extraction methods, the results achieved depend on the solvent-to-oil ratio, the selected extraction solvent, the efficiency of the extractor stages, the number of stages, and co-current or counter-current operation. Using an efficient extractor, 7% rum spot carbon and 20% Na
lco) stable oxidizer-treated diesel oil was extracted with Nalco (Nalco) of 7 at a solvent-to-oil ratio of 0.56.
) Improved diesel oil stability and 0.2% rum spot carbon can be produced. 0.
At a solvent-to-oil ratio of 24 and 0.86, 0.62
% and O,z 4% ram spot carbon content can be achieved.

Utilizing product formulations or stabilizers to transform diesel oils that have been upgraded, but are still outside commercially acceptable specifications, into formulations that meet all commercially required specifications. It should be noted that it is possible to This approach can be used with the upgraded diesel oil obtained in the process of the invention.

Furthermore, the significantly lower solvent-to-oil ratio required for the reacted feedstock is accompanied by a surprisingly increased oil yield; therefore, the process according to the invention is substantially lower than previously achieved. and provides substantially improved yields at more economical solvent-to-oil ratios.

The extraction solvents used in the present invention can be used in their commercially available forms as described above, or may be present in enhanced commercially available forms. Undesirable components can be removed.

Step (e) of the present invention is the reaction step (a) of the method of the present invention.
and recovering the purified diesel oil substrate resulting from extraction (b).

Conventional purification procedures can be used to remove extraction solvent from diesel oil. These extraction procedures include distillation, fractional crystallization, aqueous and subsequent distillation, and other suitable procedures for removing the extraction solvent from the oil matrix. The method of the present invention should not be considered limited in any way to the selection of a particular diesel oil recovery and separation procedure.

The method of the invention described above can be advantageously used to upgrade various types of petroleum derived diesel oils that contain organic compounds that cause foreign atom compound impurities and instability in the diesel oil product. Generally, a diesel oil having a heteroatomic sulfur content in the range of up to about 4% by weight is subjected to and purified according to the method of the present invention,
An improved diesel oil having a removal of sulfur impurities of at least about 30%, preferably on the order of about 75%, can be obtained while improving the stability of the product. Alternatively, a diesel oil with a relatively low initial sulfur content can be upgraded and purified according to the method of the present invention to have an improved cetane number and meet specifications for stability, rum spot carbon and sulfur products. and improved quality diesel oil with a higher proportion of slightly reduced sulfur.
It can be produced by carrying out the extraction step (b) of the invention using a low solvent to oil ratio.

Diesel oils that are not derived from petroleum generally contain high levels of aromatics, olefins, or both. The solvents used in the present invention are generally ineffective for such oils and are not suitable for petroleum oils with high levels of aromatics and olefins due to the strong affinity of the solvents used in the present invention for these compounds. Less effective.

Generally, such diesel oils exhibit poor yields at all solvent-to-oil ratios used, and many such solvents are miscible with this oil at low solvent-to-oil ratios of about 0.2 or less. It will be.

As can be seen from the examination of the essential steps in the process of the invention, the mild reaction conditions used in step (a) of the process of the invention, the simple adjustment of the essential parameters to be adjusted, the efficiency of the extraction solvent used and Because of the selectivity and lower temperatures, lower pressures, and reduced complexity involved, the present invention provides a significantly economical and advantageous process.

This is especially true when compared to the high temperature and high pressure hydrodesulfurization processes commonly used in the past. Furthermore, the advantages of the process of the invention can be appreciated when compared with similar quality improvement processes using catalysts previously used in this field. This is because the method of the present invention does not require expensive catalysts and does not require steps for catalyst separation and regeneration.

Thus, the method of the present invention is believed to be a significant advance over current technology for improving the cetane number and thus upgrading diesel oils containing sulfur impurities or other instability-producing impurities, and It is believed to have particular commercial significance.

As indicated above, the method of the present invention is used to refine and improve diesel fuel oil, reduce sulfur content, improve stability, increase cetane number, and reduce rum spot carbon content. can be done. Generally, after the reaction in step (a) of the present invention, a sulfur content of up to about 4% by weight, a stability of up to about 20 or more as determined by the Nalco test, and a rum spot carbon content of up to about 15% or more. The diesel oil having Nalco is refined and upgraded according to the method of the present invention to a degree of removal of sulfur impurities from about 5 to 70%, including Nalco improvement to about 7% or less. ram spot carbon content, including improved stability, improved cetane number for the product of the process of the present invention of about 5 to 20 cetane numbers over the feed, and the ability to achieve a rum spot carbon content of less than about 0.3%. It is possible to obtain diesel oil with a significant reduction in .

Furthermore, the diesel oil upgraded according to the method of the present invention can be used as such or as a compounding feedstock to produce desired products, such as diesel oil with improved cetane number. For example, the high cetane, low sulfur raffinate obtained according to the method of the present invention has adequate stability but cannot be blended with other diesel fuels or cycle oils that have low cetane numbers and, in some cases, high sulfur content. As a result, diesel fuel can be obtained that meets standard commercial product specifications.

Furthermore, each of the embodiments of the method of the invention described above can advantageously be carried out batchwise, semi-continuously or continuously.

The following examples further illustrate the method of the invention. These specific examples are provided for illustrative purposes only and should not be construed as limiting in any way the practice of the methods of the invention. In the examples below,
Unless otherwise specified, the reaction of diesel oil with an oxidizing agent consisting of an oxidizing gas can accommodate 1 liter of feed;
A semi-batch reactor system consisting of a jacketed cylindrical vessel was used. This reactor is made of Teflon (Te).
It was equipped with an impeller drive shaft terminating in a f lon or stainless steel impeller. This reactor was further equipped with a thermometer, a sample removal tube and a glass condenser.Oxidizing Gas was introduced via a sparger. In the following examples, the diesel oil used had the properties shown in Table 1 above.

The procedure used for the reaction of the oxidizing gas with diesel oil was to feed a weighed amount of approximately 400 g of diesel oil into the reactor, unless otherwise specified. From the weight of the supplied oil and its chemical analysis, the total number of moles of sulfur heteroatomic compounds and nitrogen heteroatomic compounds, cetane number, and rum spot carbon content were known.

The flow rate of oxidizing gas into the reactor was set by considering the oxidizer to diesel gas oil weight ratio and contact time. The weight ratios described in the examples below are the ratio of the total weight of oxidizer used to the total weight of oil fed for a particular contact time. Adjustment of flow rate was performed using an appropriately calibrated rotameter. 5.15.Various contact times for reactions of 30 and 60 minutes, 0. O1~0
．． Various weight ratios of 14 oxidizers to total feed weight,
An initial reaction temperature of 25°C was used unless otherwise specified. When nitrogen dioxide is used as an oxidizing agent, it is
It was mixed with air at a weight ratio of parts by volume of nitrogen dioxide to 4 parts by volume of air. When ozone was used as the oxidizing agent, the ozone was generated at a volume ratio of approximately 1 part by volume ozone to 1 part by volume oxygen before being introduced into the reaction.

In operation, when using a gaseous oxidizer, after calculating the appropriate rotameter settings, feed the diesel oil feed into the reactor, heat the reactor to the specified temperature,
The rotameter valve was opened to allow the appropriate oxidizing gas to flow into the reactor and a timer was started. The reaction mixture was stirred with a stirrer. The temperature was measured at appropriate intervals, and at the end, the flow of oxidizer gas was stopped, and a sample of the oxidized diesel oil was taken for analysis. Then, the remainder of the reacted oil was used for extraction. did.

All solvent extractions were single step batch extractions unless otherwise noted. In the extraction described in the examples below, approximately 20 ml of oil was poured into a 60 ml separatory funnel.The solvent used was then added to the oil in the separatory funnel in the appropriate weight ratio to the oil. The separatory funnel was then shaken and left at room temperature for 1-30 minutes to achieve complete separation. After the system has stabilized, the extraction phase (containing solvent, sulfur-containing compounds, compounds causing instability, nitrogen-containing compounds and cetane-inhibiting compounds) is collected and the raffinate (oil + a small amount of dissolved solvent) is collected. determined the rate. The raffinate was also washed twice with water after each extraction and before measuring raffinate oil yield, with a water to raffinate weight ratio of 1.0 for each wash. After washing, the final oil obtained (from which the solvent has been removed)
were collected and weighed.

Analysis of sulfur is performed using Prin
It was carried out using a ceton Gamma-Tech) Model 100 chemical analyzer. Stability testing was performed using the standard Nalco test. This is 1For example,
It was carried out as follows. Heat the tube containing the sample for 90 minutes, then filter the heated oil through a microporous filter and no.

1 filter paper, then the filter and filter paper were washed with heptane, and the remaining retentate was compared to a standard sample. Determination of the cetane number of the resulting diesel fuel was performed using a diesel test engine (ASTM 0613).
It was carried out using Lumspotum carbon content (ASTM
D524) was distilled 90% overhead and a portion of the bottom liquid was taken, 10% of which was combusted in a ram spot furnace, after which the residue was weighed.

Unless otherwise specified herein, all parts, percentages, ratios, etc. are by weight.

Comparative Example 1 Samples of virgin atmospheric gas oil (as listed in Feedstock C1 Table 1) were individually contacted with each solvent listed in Table 4 below. This feedstock was not reacted before extraction. 20m each
1 of the oil sample was contacted with the extraction solvent for 1 minute by shaking with 20 ml of each solvent. After phase separation occurred, the raffinate yield was determined and each sample was evaluated for sulfur content.

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Seven noeta/-1 and 7 min, bean paste, 0 1
．． 08 9.2 JL-5 Fuki Δ Kokonto> Glico-11/ 95.1
1.19 01-me4-11/-2-biridone 79.8 0.72
39.5 methanol) l/87.8
1.14 4.2101' As the results shown in Table 4 demonstrate, when the oil has not been previously oxidized, a wide range of solvents conventionally used in prior art methods for extraction and impurity removal can be used. High yields of oil (greater than about 90%) with high degrees of sulfur heterocompound removal (greater than about 40%) have not been achieved using this method. Additional solvents were tested at this solvent to oil ratio but were found to be unsuitable for extraction due to miscibility. These solvents are acetone, hexane, 2-
They were butanone, 2-octanone, nitrobenzene, isobutylamine, diethylamine, ethyl acetate, pyridine, methylene chloride, diethyl ether, 2-propanol, trichloroethane, and trichloroethane.

Comparative Example 2 0.5 of atmospheric gas oil and feedstock C as shown in Table 1
A small sample was reacted with an oxidant at 10° C. and 1 atm using a flow of 25% nitrogen dioxide in air for a contact time of 60 minutes.

102' The severity of the reaction is measured by the weight ratio of No2/oil, which is defined as the ratio of the weight of N02 added to the weight of feed oil within a given contact time. In this reaction, No.
The 2/oil ratio was approximately 0.04. A 20 ml sample of this oxidized oil was then mixed with 2 mL of each solvent listed in Table 5 below.
0 ml and extracted according to the same procedure as described above in Comparative Example 1.

From FIG. 3, comparisons of extraction yields must be performed at equal levels of oxidation severity, taken as sulfur reduction across the treatment reactors.

All severities in Table 5 are approximately equal.

The yields in Table 5 for phenol and aniline are at least 10% too high because these solvents are not removed by water washing. Also, ethylenediamine is unsuitable due to its reactivity, as discussed in Comparative Example 7 below.

All solvents in Table 5 with low dipole moments are
Gives low yields, low sulfur removal, or both.

Additional solvents tested at this solvent to oil ratio and found to be unsuitable for extraction due to miscibility were acetone, hexane, 2-butanone, 2-octanone, nitrobenzene, isobutylamine, diethylamine, ethyl acetate. ,
They were pyridine, methylene chloride, diethyl ether, 2-propanol, trichloroethane, and trichloroethane.

Comparative Example 3 A 1 liter sample of atmospheric gas oil, feedstock C1, as described in Table 1, was prepared at 15.30.60° C. and 1 atm using a flow of 15% by weight nitrogen dioxide in air.
The severity of the 0 reaction with the oxidizer for a contact time of 80 minutes is measured by the N02/oil weight ratio, which is the weight of NO2 added within a given contact time versus the feed oil. It is defined as the ratio of weights. 1 of each oxidized oil
．． Washing was carried out with a water/voltage ratio of 0. Improvements in sulfur removal and high cetane numbers in the oil were achieved, as shown in Table 1, and both increased as NO2/oil increased. There is an unavoidable undesirable increase in Nalco stability ratings and rum spot carbon to unacceptable levels. Although oxidation improves the cetane number and removes sulfur from the oil, it produces an oxidized oil that is unacceptably unstable and has a poor rum spot carbon content.

As this comparative example clearly shows, prior art teachings of nitrogen oxide reactions improve the cetane rating of diesel fuels, but the stability and ram spot carbon acceptability, which are commercially important specifications for diesel fuels. accompanied by irreversible deterioration. Contact of this product with alkali, even at uneconomically high levels, is insufficient to improve it.

Comparative Example 4 Samples of virgin, untreated atmospheric gas oil, listed as Feedstock C in Table 1, were individually contacted with each of the solvents listed in Table 7 below.

Each 20 ml sample of oil was contacted with each solvent by contacting for 1 minute at the indicated solvent to oil ratio. Separated diesel oil (raffinate) after phase separation occurs
The yield of was determined and each sample was analyzed for sulfur content and cetane number. As the results show, 40% at the same time
High yields of oil greater than 90% could not be achieved with greater sulfur removal and substantial cetane number improvement. Additionally, for the data in Table 7, without pretreatment with nitrogen-containing oxidizers or ozone, uneconomically high solvent-to-oil ratios with associated low raffinate yields substantially remove sulfur. and is required even to moderately improve the cetane number.

Attempting to adjust the rum spot carbon and stability by decreasing the acid/oil ratio in the reaction, we added 2 atmospheric gas oils to the feedstocks listed in Table 1 with 90% HNO3 and 0. The reaction was carried out at an acid to oil weight ratio of 0.0025. The cetane rating of the reacted diesel oil was only 48 and the nitrogen content was 350 ppm.

The rum spot carbon content of the reacted diesel oil is 1.52
%, well above the commercial standard of 0.3% for diesel fuel. Although Nalco stability was not measured, significant deposits formed after 20 days of storage, indicating a stability rating of greater than 15.

It does not seem possible to significantly improve the cetane number by reaction with a nitrogen-containing oxidizing agent, without facing selectivity problems of simultaneous reactions, which are detrimental to specifications on ram spot carbon and stability. There wasn't.

Comparative Example 6 Nitrogen is known to contribute to rum spot carbon and stability issues in diesel fuel. Therefore, the nitrogen removal solvent disclosed in U.S. Pat. No. 4,485,007 as an excellent nitrogen removal solvent,
Formic acid was tested.

The feed stock CC listed in Table 1 was reacted with gaseous nitrogen dioxide and extracted with formic acid at a solvent to oil ratio of 1.0 according to the procedure of US Pat. No. 4,485,007. The resulting raffinate product still had a rum spot carbon content of 1.5% and a stability of 17. As these poor results demonstrate, ram spot carbon and stability control require more than a good nitrogen-scavenging solvent. As taught by the present invention, formic acid, which has a dipole moment of 1.2, does not meet the dipole moment criteria of the present invention and is not a suitable solvent.

In conclusion, the reactions of nitrogen-containing oxidants are complex, the individual compounds removed during extraction are unknown, and the specific properties that affect rum spot carbon and stability are unpredictable. The resulting 1 reaction-extraction results are poor, but based on the prior art one would have expected them to be very good. Thus, the cetane-ramsbottom carbon-stability properties of reacted diesel fuels are conventionally difficult to predict and cannot be achieved using the teachings of the prior art.

Comparative Example 7 Similarly, using the procedure described above, U.S. Patent No. 4,485.0
The ethylene diamine disclosed in No. 07 was used to extract the reacted diesel oil of feedstock X listed in Table 1. This diesel oil was reacted with the nitrogen-containing oxidizer nitric acid at a nitric acid to oil weight ratio of 0.01. Substantial heat and fumes were released. It is probably the result of an acid-base reaction involving the amine group of the active base. This amine solvent could not be used in the process of the invention due to its reactivity with oxidizing agents.

Comparative Example 8 Gaseous nitrogen dioxide, liquid nitrogen dioxide, and 90% nitric acid were added as oxidizing agents to a well-mixed sample of diesel oil, cycle oil, and raw oil V having the characteristics shown in Table 1, as shown in Figure 3. Added at a rate sufficient to provide the indicated nitrogen content. The cetane rating of each oil sample was determined. The results are also shown in Figure 4 after washing with 1:1 oil to water.

As can be seen, all three nitrogen-containing oxidizers provide equivalent cetane grades of the produced oil product. However, similar to the results obtained in Comparative Example 1, all products exhibited poor stability and rum spot carbon content due to the lack of solvent extraction. In fact, within the few minutes required for the cetane engine test, the oil injector in the herring became substantially fouled and the product of Comparative Example 8 was tested as a diesel fuel, despite the high cetane rating in Figure 4. Reveal inappropriateness.

Example 1 A sample of atmospheric gas oil of feedstock C shown in Table 1 was reacted with an oxidizer according to the procedure described in Comparative Example 2 above at a nitrogen dioxide weight to diesel oil feed weight ratio of about 0.014. I let it happen.

After the reaction, a sample of the oil that had reacted with the oxidizing agent was extracted with the solvents listed in Table 8 below, following the extraction procedure described in Comparative Example 1 above. The results obtained are shown in Table 8 below.

Results of the present invention shown in Table 8 and Table 4 without oxidizing agent treatment
By comparing the results of the comparative example shown in Table 5 with the results of the comparative example shown in Table 5 for the inferior solvent, it is clear that substantial improvements in both yield and sulfur removal were achieved.

As can be seen, the product reacted with the oxidizing agent and extracted showed superior yield and sulfur removal compared to the unreacted extracted oil product produced in Comparative Example 1. .

Example 2 Atmospheric gas oil samples of Feedstock C shown in Table 1 were reacted except that 6.5% by weight of ozone and oxygen were used to react 2.
Contact was made for 40 minutes. The weight ratio of ozone to the total weight of the atmospheric gas oil feed was about 0.029.

After the reaction, a sample of the oil that had reacted with the oxidizing agent was extracted using the solvents listed in Table 9 below according to the procedure described in Example 1 above. The results obtained are shown in Table 9, which shows a substantial improvement in oil yield or sulfur removal compared to Table 4.
As shown in Figure 3, sulfur removal and oil yield are correlated by adjusting the solvent to oil ratio. therefore,
One skilled in the art can adjust the conditions used to produce the results in Table 9 to achieve superior results in both yield and sulfur removal compared to the results in Table 4.

Furthermore, three samples of atmospheric gas oil of feedstock X shown in Table 1 were mixed with 10% by weight of ozone in air at 25°C.
The reaction was carried out for reaction times of 5 and 22 hours. The cetane number and sulfur removal of oils reacted with oxidant increased with increasing oxidant/oil contact time, as shown in Table 10 below.

Although the prior art suggests that nitrogenation is necessary to improve cetane grades, ozonation also improves cetane grades, as the results in Table 10 below demonstrate. An attempt was also made to measure the stability of the oxidant-reacted oil before extraction, but the stability was so poor that the filter clogged, making stability measurements impossible.

Person 1A (time) (%) 0 1.07 58.06
0.95 B3.015
0.75 71.422
0.50 75.0 Oxidation for 15 hours as in Example 2 and extraction of the products in Table 10 with one of the preferred solvents of the invention, gamma-butyrolactone, as evidenced by the results in Table 11 below: Excellent stability was obtained.

Person 1 unit Sulfur yield Sulfur content Koan removal S10 ratio -Ω6) (%) Qualitative (%) 0.
25 90.0 0.35 4 53.30.50
88.0 0.28 5 B2.71.00 87
．． 0 0.18 3 76.0 As further evidenced by the results in Table 11 above, ozone is a suitable oxidizing agent for use in the method of the present invention. Furthermore, as these results in Table 10 demonstrate, the improvements obtained in cetane number are not only due to nitrogenization of the feedstock. because,
This is because ozone, an oxidizing agent that does not contain nitrogen, was used in this case.

The reaction between the oxidizing agent and the oxidizing agent was carried out under variable oxidizing conditions varying from mild to severe.Then, each of the atmospheric gas oils that had reacted with the oxidizing agent was shown in Figure 3 in four different directions, either to the left or to the right. Extracted with gamma-butyrolactone at different solvent to oil ratios of 0.1.0.2.0.5 and 1.0. The results shown in FIG. 2 are reproduced in FIG. 3, and again the S10 ratios for extraction of unprocessed oil are shown in the data points. The results obtained are shown in Table 12 below and in Figure 3, which shows the effect of oxidant reaction conditions on extraction with gamma-butyrolactone on raffinate yield and sulfur content.

As is clear from the results shown in Table 12 and Figure 3, excellent yields of raffinate can be achieved with substantial improvements in sulfur removal. In particular, sulfur extraction is much more effective in the oil after oxidant reaction, and for the same sulfur removal rate (in the extraction step only), even with a very mild oxidant treatment, The yield of extracted oil is higher for the reacted oil (1.1% S in the product oil) than for the unreacted oil, and this increase is further improved with increasing severity in the oxidation reaction. Additionally, large savings in solvent recovery were observed. For example, a solvent to oil (S10) ratio of 5.0 is required for 50% removal of sulfur from an unoxidized oil (1.19% S), but an oxidized oil containing 1.1% sulfur A solvent-to-oil (S10) ratio of only 1.0 was sufficient to obtain the same sulfur removal rate in oils with higher yields. The effect of oxidation conditions on the properties of these important products with respect to the levels of oxidation is described.

As is clear from Figure 3, comparisons of the effectiveness of various solvents must take into account the severity of the oxidation, and different yields can be achieved at different levels of sulfur removal. Furthermore, the diesel oil feed used influences the results obtained. Although these complexities have been considered in the examples herein, care must be taken when making comparisons beyond those contained within each individual table herein.

Example 4 A 1 liter sample of the atmospheric gas oil of the feedstock CC listed in Table 1 was prepared using 90% HNO3.
The resulting oxidizer-reacted oil was then oxidized for 30 minutes according to the method of the present invention at a temperature of 25° C. in the weight ratio of 3/0 diesel oil feed to a mixture of dimethylformamide and water as listed in Table 13 below. was used to extract according to the extraction procedure described in Comparative Example 1 above. The results obtained are listed in Table 13 below. These results indicate that the moisture content of the solvent can be adjusted to further improve the yield of the products of the invention.

Still further, selected solvents of the present invention were compared to the comparative solvents in Table 14. Raffinates from high dipole moment solvents have improved sulfur levels, yields and rum spot carbon, and improved stability compared to raffinates obtained using comparison solvents.

Still further, the other solvent of the present invention, furfural, is
In Table 15 it is shown to have improved sulfur removal compared to methanol even when run at significantly lower solvent to oil ratios.

″>1 12! :1.

Example 5 A 1 liter sample of the atmospheric gas oil of the feedstock CC listed in Table 1 was prepared using 90% HNO3.
oxidized according to the method of the invention for 30 minutes at a temperature of 28° C. in the weight ratio of a/diesel oil feed. Before introducing the oxidizer into the reactor, H2SO4 was
Added to 90% HNO3 at different concentrations. The resulting oxidized oil was then extracted with gamma-butyrolactone at a solvent to oil ratio of 0.5 following the extraction procedure described in Comparative Example 1 above. The results obtained are listed in Table 14 below. With the present invention, very good cetane, rum spot coal grades, stability and yields were achieved, whereas H2S04 (see Table 16) alone gave poor cetane grades.

Example 6 Several diesel oils listed in Table 17 below (feedstock oils with properties listed in Table 1) were mixed with 90% HNO3 and 0.01
The reacted oil was extracted with selected solvents of the present invention under various extraction conditions.

The results are summarized in Table 17 below, which shows the ratio of cetane in the raffinate to cetane in the reacted diesel oil.Over a wide range of conditions, greater than 95% of the cetane in the reactor product was retained. Lum spotom carbon content and stability were greatly improved. As these data show,
Cetane could be controlled in the reactor and was not lost during extraction with the solvent of the invention. In contrast, as disclosed in British Patent No. 491,648, cetane was lost when using the solvents disclosed therein. As Table 17 shows, in contrast to the prior art effects shown in Table 7, extraction did not contribute to the achieved cetane grade.

Example 7 The oxidized oil product from Comparative Example 3 was subjected to a more extensive phase equilibrium analysis. Without wishing to be bound by theory, it is believed that the addition of foreign atoms to the substrate material increases the affinity of the solvent during the extraction step, thereby improving the yield. By preferentially adding foreign atoms to molecules that also contain sulfur atoms,
It is a particularly surprising aspect of the process of the invention that this allows selective extraction of sulfur compounds.

The fundamental shift in extraction equilibrium is dramatically evident from the ternary equilibrium diagrams shown in Figures 5 and 6, where the solvent (gamma-butyrolactone) %
, % sulfur, and % oil are shown. The equilibrium compositions of the raffinate and extraction phases from the extraction are connected by solid lines.

Several lines are shown at several different solvent to oil ratios.

As is clear from FIG. 5, diesel fuel with no oxidant reaction (1°19% sulfur used in Example 3)
Equilibrium data for do not provide a basis for improvement. In particular, the phase line exhibits a negative slope, indicating low selectivity in removing sulfur from oxidant-unreacted diesel oil.For example, point R1 is where the raffinate phase is 2% gamma-butyrolactone and 0. It shows a sulfur content of 97%, whereas the corresponding extraction phase E1 contains 91% sulfur.
gamma-butyrolactone and 0.4% sulfur. In extraction methods aimed at removing sulfur, a higher sulfur content of the extraction phase would be desirable; these poor results explain the performance of the various solvents in Table 4.

In contrast, when practiced according to the present invention, the diesel fuel is first reacted with an oxidizer prior to extraction, as described in Example 3. Equilibrium data for diesel oil reacted with an oxidizer are shown in FIG. These data show a desirable positive slope. Point R1 indicates that the raffinate contained 0.36% sulfur along with about 2% gamma-butyrolactone; the corresponding extraction phase was 1.
It contained 24% sulfur along with about 46% gamma-butyrolactone. Here, this oxidized oil exhibits extremely excellent extraction efficiency, unlike the comparative diesel oil shown in FIG. 5 that has not reacted with the oxidizing agent. These excellent results explain the superiority of the various solvents of the invention shown in Table 8.

EXAMPLE 1 A 1 liter sample of atmospheric gas oil of feedstock CC listed in Table 1 was treated with 0.0% by weight HNO3. The reaction was carried out at an acid/oil (A10) ratio of OI at 10° C. and 1 atmosphere pressure with a contact time of 60 minutes. The A10 ratio is defined as the ratio of the weight of HNO3 added during the contact time (calculated as 100% HNO3) to the weight of the oil fed after each 20 ml sample of the oxidizer-reacted diesel oil sample. was brought into contact with each solvent shown in Table 18 below according to the procedure described in Comparative Example 2. As can be seen from the results, extraction of oxidant-reactive diesel oil with the selective solvent of the present invention improves the Nalco stability and rum spot carbon of the diesel oil while retaining its increased cetane number. .

Additionally, in Table 18, one solvent was tested in countercurrent extraction, showing similar efficacy to that practiced commercially. The yield, sulfur removal, and stability of O. hyalus phototom carbon are all further improved with respect to the excellent results shown in Tables 8 to 16 herein.

3B Isamu Jose 1 Five samples of diesel oil of feedstock X listed in Table 1 were oxidized using 90% HNO at the following AZO ratio: 0.0012.0.0025.0. 0050.0.
010 and 0.05゜ These oxidant-reactive oils were mixed with DMF
Further extraction was performed to determine the correlation between oxidation conditions and raffinate yield.

Table 19 below shows the results obtained for five semi-batch oxidations together with the cetane numbers of the oxidant reacted oils.

The effect of increase in cetane number as a result of oxidation on the total yield of raffinate for oxidation-extraction is shown in Table 20 below.
The total sulfur removal of 50% shown in Table 1 is used as a reference point and the total yield corresponding to the cetane number increase of the oxidant-reacted diesel oil due to oxidation is stated. As the data show, an increase in cetane number in step (a) as in the present invention is required to produce a yield direction E in the subsequent extraction step (b), and an increase in raffinate yield is A similar correlation exists for gamma-butyrolactone, which increases with increasing cetane number.

Although the invention has been described in terms of specific embodiments thereof,
Modifications and changes can be made without departing from the spirit and scope of the invention, as will be apparent to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a route map of one embodiment of the present invention. FIG. 2 shows the results of extracting atmospheric gas oil with gamma-butyrolactone. FIG. 3 shows the effect of atmospheric gas oil oxidation on gamma-butyrolactone extraction. FIG. 4 shows the relationship between the increase in cetane number and the N content in oils that have reacted with an oxidizing agent but are not extracted with a solvent. FIG. 5 graphically shows the results obtained for the extraction of oxidant-reacted diesel oil, depending on the sulfur content present and the extraction solvent content. FIG. 6 is a graphical representation of the equilibrium data obtained for the extraction of oxidizer reacted diesel oil. l Diesel oil feed 2 Nitric acid inlet 3 Reactor 4 Oxidized product 5 By-product residue 6 Solvent extractor 7 Extraction solvent 8 Extraction phase 9 Oxidized raffinate phase 10 Solvent recovery device 11 Residual solvent 12 Quality Improved Diesel Fuel Patent Applicant Environmental Research Ant-Fist Technology Innie Volated

Claims (1)

[Claims] 1. Step: (a) Derived from petroleum source, from about 149°C to about 3°C at normal pressure
Diesel oil having a boiling point of 71°C (approximately 300°F to 700°F) is reacted with an oxidizing agent selected from the group consisting of a nitrogen-containing oxidizing agent and ozone, wherein (1) the reaction comprises step (a) (2) (i) the reaction is sufficient to increase the cetane number of the diesel oil obtained in step (a) by at least 5 cetane numbers over the cetane number of the diesel oil feed to step (a); When the oxidizing agent is a nitrogen-containing treatment agent, an amount of oxidizing agent equal to a 100% nitric acid basis is added to the process (
and (ii) the reaction is such that the amount of oxidizing agent is less than about 10% by weight of the diesel oil feed to step (a), and (ii) the oxidizing agent is ozone. process (a
) which is sufficient to reduce the sulfur content of the reacted diesel oil obtained in step (a) by more than about 10%; (b) the diesel oil from step (a) above is treated with an extraction solvent;
The extraction solvent (1) has a dipole moment of about 2 or more, (2) is substantially immiscible with diesel oil at the temperature of contact with the diesel oil obtained in step (a), and (3) a non-halogenated solvent and (4) excludes amines that are reactive with oxidizing agents; in contact with
and (c) separating the diesel oil from step (b) above from the extraction solvent to recover the improved diesel fuel. A method of producing improved diesel fuel. 2. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is an oxidizing gas consisting of at least one nitrogen oxide having more than one oxygen atom for each nitrogen atom. The method described in item 1. 3. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is an oxidizing liquid comprising at least one nitrogen oxide having more than one oxygen atom for each nitrogen atom. The method described in item 1. 4. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is nitric acid or nitrous acid and about 0 to 90
2. The method of claim 1, wherein the oxidizing liquid consists of % water by weight. 5. The method according to claim 1, wherein the oxidizing agent is ozone. 6. The method according to claim 1, wherein the reaction step (a) is carried out in the presence of at least one acid selected from the group consisting of organic acids, inorganic acids, and mixtures thereof. 7. The method of claim 6, wherein said organic acid is selected from the group consisting of acetic acid and formic acid, and said inorganic acid is selected from the group consisting of sulfuric acid and phosphoric acid. 8. The organic acid is present in an amount of about 5 to about 200% by weight, and the inorganic acid is present in an amount of about 5 to about 200% by weight, each based on the diesel oil. The method described in section. 9. The nitrogen-containing oxidizing agent is about 0.00% nitrogen equivalent to the diesel oil on a nitrogen equivalent basis to 100% nitric acid.
Claim 1 used in a weight ratio of 0.01 to about 0.1
The method described in section. 10. The nitrogen-containing oxidizing agent is about 0.0005 to about 0.000.
10. The method according to claim 9, wherein the weight ratio is 0.05. 11. The weight ratio of the extraction solvent to the diesel oil is about 0.
．． 5. The method of claim 1, wherein the molecular weight is from 0.01 to about 5. 12. The weight ratio of the extraction solvent to the diesel oil is about 0.
．． 12. The method of claim 11, wherein the molecular weight is between 0.05 and about 1.0. 13. The method of claim 1, wherein the diesel oil contains less than about 40% aromatics by weight. 14. The method of claim 1, wherein the diesel oil contains less than about 35% by weight olefins. 15. The method of claim 1, wherein the diesel oil contains less than about 40% by weight aromatics and less than about 35% by weight olefins. 16. Process: (a) Derived from petroleum source, at normal pressure from about 149°C to about 3
Diesel oil having a boiling point of 71°C (approximately 300°F to 700°F) is reacted with an oxidizing agent selected from the group consisting of a nitrogen-containing oxidizing agent and ozone, wherein (1) the reaction comprises step (a) (2) (i) the reaction is sufficient to increase the cetane number of the diesel oil obtained in step (a) by at least 5 cetane numbers over the cetane number of the diesel oil feed to step (a); When the oxidizing agent is a nitrogen-containing treatment agent, an amount of oxidizing agent equal to a 100% nitric acid basis is added to the process (
and (ii) the reaction is such that the amount of oxidizing agent is less than about 10% by weight of the diesel oil feed to step (a), and (ii) the oxidizing agent is ozone. process (a
) which is sufficient to reduce the sulfur content of the reacted diesel oil obtained in step (a) by more than about 10%; (b) the diesel oil from step (a) above is treated with an extraction solvent;
The extraction solvent (1) has a dipole moment of about 2 or more, (2) is substantially immiscible with diesel oil at the temperature of contact with the diesel oil obtained in step (a), and (3) It is a non-halogenated solvent, (4) eliminates amines that are reactive with oxidizing agents, and (5) has the following functional groups: ▲Mathematical formulas, chemical formulas, tables, etc.▼
Contains at least one of the following: , ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and ▲There are mathematical formulas, chemical formulas, tables, etc.▼ contacting said solvent mixture or a mixture of said solvent and water such that said solvent contains no more than about 50% by weight water;
and (c) separating the diesel oil from step (b) above from the extraction solvent to recover the improved diesel fuel. A method of producing improved diesel fuel. 17. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is an oxidizing gas consisting of at least one nitrogen oxide having more than one oxygen atom for each nitrogen atom. The method according to item 16. 18. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is an oxidizing liquid comprising at least one nitrogen oxide having more than one oxygen atom for each nitrogen atom. The method according to item 16. 19. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is nitric acid or nitrous acid and about 0 to 9
17. The method of claim 16, wherein the oxidizing liquid is 0% by weight water. 20. Claim 16, wherein the oxidizing agent is ozone.
The method described in section. 21. The method according to claim 16, wherein the reaction step (a) is carried out in the presence of at least one acid selected from the group consisting of organic acids, inorganic acids, and mixtures thereof. 22. The method of claim 21, wherein said organic acid is selected from the group consisting of acetic acid and formic acid, and said inorganic acid is selected from the group consisting of sulfuric acid and phosphoric acid. 23. The organic acid is present in an amount of about 5 to about 200% by weight, and the inorganic acid is present in an amount of about 5 to about 200% by weight, each based on the diesel oil. The method described in section. 24. The nitrogen-containing oxidizing agent is about 0.0% nitrogen equivalent to the diesel oil on a nitrogen equivalent basis to 100% nitric acid.
17. The method of claim 16, wherein a weight ratio of from 0.001 to about 0.1 is used. 25. The nitrogen-containing oxidizing agent is added to a concentration of about 0.0005 to about 0.000.
25. The method according to claim 24, wherein the weight ratio is 0.05. 26, the weight ratio of the extraction solvent to the diesel oil is about 0;
．． 17. The method of claim 16, wherein the molecular weight is from 0.01 to about 5. 27. The weight ratio of the extraction solvent to the diesel oil is about 0.
．． 27. The method of claim 26, wherein the molecular weight is between 0.05 and about 1.0. 28. The method of claim 16, wherein the diesel oil contains less than about 40% aromatics by weight. 29. The method of claim 16, wherein the diesel oil contains less than about 35% by weight olefins. 30. The method of claim 16, wherein the diesel oil contains less than about 40% by weight aromatics and less than about 35% by weight olefins. 31. Process: (a) Derived from petroleum source, at normal pressure from about 149°C to about 3
Diesel oil having a boiling point of 71°C (approximately 300°F to 700°F) is reacted with an oxidizing agent selected from the group consisting of a nitrogen-containing oxidizing agent and ozone, wherein (1) the reaction comprises step (a) (2) (i) the reaction is sufficient to increase the cetane number of the diesel oil obtained in step (a) by at least 5 cetane numbers over the cetane number of the diesel oil feed to step (a); When the oxidizing agent is a nitrogen-containing treatment agent, an amount of oxidizing agent equal to a 100% nitric acid basis is added to the process (
and (ii) the reaction is such that the amount of oxidizing agent is less than about 10% by weight of the diesel oil feed to step (a), and (ii) the oxidizing agent is ozone. process (a
(b) the diesel oil from step (a) above is treated with furfural, butyrolactone, dimethylformamide, etc. which is sufficient to reduce the sulfur content of the reacted diesel oil obtained in step (a) by about 10% or more; , methyl carbitol, tetrahydrofurfuryl alcohol, dimethyl sulfoxide, sulfolane, sulfolene, dimethyl acetamide, 1-methyl-2-pyrrolidone, acetonitrile, acetic anhydride, nitrobenzene, nitromethane and mixtures thereof, or up to 50% by weight and (c) separating said diesel oil from step (b) above from said extraction solvent to obtain upgraded diesel. A method for producing improved diesel fuel by improving the quality of diesel oil, the method comprising: recovering fuel. 32. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is an oxidizing gas consisting of at least one nitrogen oxide having more than one oxygen atom for each nitrogen atom. The method according to item 31. 33. The oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is an oxidizing liquid comprising at least one nitrogen oxide having more than one oxygen atom for each nitrogen atom. The method according to item 31. 34, the oxidizing agent is a nitrogen-containing oxidizing agent, and the nitrogen-containing oxidizing agent is nitric acid or nitrous acid and about 0 to 9
32. The method of claim 31, wherein the oxidizing liquid is 0% by weight water. 35. Claim 31, wherein the oxidizing agent is ozone.
The method described in section. 36. The method according to claim 31, wherein the reaction step (a) is carried out in the presence of at least one acid selected from the group consisting of organic acids, inorganic acids, and mixtures thereof. 37. The method of claim 36, wherein said organic acid is selected from the group consisting of acetic acid and formic acid, and said inorganic acid is selected from the group consisting of sulfuric acid and phosphoric acid. 38, wherein the organic acid is present in an amount of about 5 to about 200% by weight, and the inorganic acid is present in an amount of about 5 to about 200% by weight, each based on the diesel oil. The method described in section. 39. The nitrogen-containing oxidizing agent has a nitrogen equivalent ratio of about 0.0 to the diesel oil on a nitrogen equivalent basis to 100% nitric acid.
32. The method of claim 31, wherein a weight ratio of from 0.001 to about 0.1 is used. 40, the nitrogen-containing oxidizing agent is about 0.0005 to about 0.40%.
39. The method according to claim 39, wherein the weight ratio is 0.05. 41, the weight ratio of the extraction solvent to the diesel oil is about 0;
．． 32. The method of claim 31, wherein the molecular weight is from 0.01 to about 5. 42. The weight ratio of the extraction solvent to the diesel oil is about 0.
．． 32. The method of claim 31, wherein the molecular weight is between 0.05 and about 1.0. 43. The extraction solvent is butyrolactone, dimethylformamide, methyl carbitol, tetrahydrofurfuryl alcohol, dimethyl sulfoxide, sulfolane, dimethyl acetamide, or a mixture thereof;
32. The method of claim 31, wherein the method is selected from the group consisting of mixtures thereof with water containing up to % by weight of water. 44. The extraction solvent consists of butyrolactone, methyl carbitol, tetrahydrofurfuryl alcohol, dimethyl sulfoxide, sulfolane, dimethyl acetamide, or mixtures thereof, or mixtures thereof with water containing up to 50% by weight of water. 32. The method of claim 31, wherein the method is selected from the group. 45. The extraction solvent of claim 31 is selected from the group consisting of furfural, butyrolactone, dimethylformamide, or mixtures thereof, or mixtures thereof with water containing up to 50% by weight of water. Method. 46. The method of claim 31, wherein the extraction solvent is selected from the group consisting of furfural or a mixture thereof with water containing up to 50% by weight of water. 47. The method of claim 31, wherein the extraction solvent is selected from the group consisting of butyrolactone or a mixture thereof with water containing up to 50% by weight of water. 48. The method of claim 31, wherein the extraction solvent is selected from the group consisting of dimethylformamide or a mixture thereof with water containing up to 50% by weight of water. 49, the extraction solvent is dimethylacetamide, or 5
32. The method of claim 31, wherein the method is selected from the group consisting of mixtures thereof with water containing up to 0% by weight of water. 50. The method of claim 31, wherein the extraction solvent is selected from the group consisting of dimethyl sulfoxide or a mixture thereof with water containing up to 50% by weight of water. 51, the extraction solvent is sulfolane or 50% by weight
32. The method of claim 31, wherein the method is selected from the group consisting of: water and mixtures thereof; 52, the extraction solvent is methyl carbitol, or 5
32. The method of claim 31, wherein the method is selected from the group consisting of mixtures thereof with water containing up to 0% by weight of water. 53. The method of claim 31, wherein the extraction solvent is selected from the group consisting of tetrahydrofurfuryl alcohol or a mixture thereof with water containing up to 50% by weight of water. 54, the extraction solvent is 1-methyl-2-pyrrolidone,
or a mixture thereof containing up to 50% by weight of water. 55. The method of claim 31, wherein the extraction solvent is selected from the group consisting of acetonitrile or a mixture thereof with water containing up to 50% by weight of water. 56, the extraction solvent is acetic anhydride, or 50% by weight
32. The method of claim 31, wherein the method is selected from the group consisting of: water and mixtures thereof; 57. The method of claim 31, wherein the extraction solvent is selected from the group consisting of nitrobenzene or a mixture thereof with water containing up to 50% by weight of water. 58. The method of claim 31, wherein the extraction solvent is selected from the group consisting of nitromethane or a mixture thereof with water containing up to 50% by weight of water. 59, the extraction solvent is sulfolene, or 50% by weight
32. The method of claim 31, wherein the method is selected from the group consisting of: water and mixtures thereof; 60. The method according to claim 31, wherein the diesel oil is petroleum-derived diesel oil. 61. The method of claim 31, wherein the diesel oil contains less than about 40% aromatics by weight. 62. The method of claim 31, wherein the diesel oil contains less than about 35% by weight olefins. 63. The method of claim 31, wherein the diesel oil contains less than about 40% by weight aromatics and less than about 35% by weight olefins.