KR20060119532A - Extraction of nitrogen and sulfur compounds from petroleum distillates using ionic liquids - Google Patents

Abstract

A method of extracting nitrogen and sulfur compounds from petroleum distillates using ionic liquids is provided to remove the nitrogen compounds and sulfur compounds more effectively by using ionic liquid which is eco-friendly solvent. The method of extracting nitrogen and sulfur compounds from petroleum distillates using ionic liquids comprises the steps of mixing (i) the C5-C50 petroleum hydrocarbon distillates containing sulfur compounds, nitrogen compounds or mixture thereof and (ii) ionic liquids and then extracting and removing the sulfur and nitrogen compounds or the mixture thereof from the petroleum hydrocarbon distillate layer as ionic liquid layer through phase separation. The ratio of the ionic liquid and the petroleum hydrocarbon(solvent to oil;SOR) is 0.01-5. The extraction through phase separation is repeated more than two times.

Description

Removal of nitrogen and sulfur compounds from petroleum hydrocarbon fraction using ionic liquids {Extraction of nitrogen and sulfur compounds from petroleum distillates using ionic liquids}

FIG. 1 is a flowchart illustrating a process of extracting or removing nitrogen and sulfur compounds in light gas oil using an ionic liquid as an application example of the present invention.

The present invention relates to a method for removing nitrogen compounds and sulfur compounds in petroleum hydrocarbon fraction using an ionic liquid, and more particularly, an ionic liquid having high solubility selectively for nitrogen compounds and sulfur compounds present in trace amounts in a hydrocarbon mixture. The present invention relates to a method for efficiently removing nitrogen compounds and sulfur compounds that need to be removed in various petroleum hydrocarbon fractions produced in a petroleum refining process through a simple and economical extraction process.

The higher the nitrogen and sulfur compounds in petroleum products, the higher the emission of harmful emissions such as SO _x and NO _x from various combustion devices such as automobile engines, and acts as a catalyst poison for automobile exhaust gas reduction devices. Nitrogen compounds and sulfur compounds in the hydrocarbon fraction in the middle of the petroleum refining process act as catalyst poisons to the catalyst used in the process to reduce the reaction efficiency and shorten the catalyst life, so sulfur compounds and nitrogen in the petroleum hydrocarbon fraction Various methods of removing compounds have been studied for decades and have been applied commercially.

As a method for removing sulfur compounds, nitrogen compounds and other impurities contained in petroleum hydrocarbon fractions, basic components such as caustic soda and amine compounds are used to oxidize and remove the methane component contained in the oil, or to convert to disulfide compounds. Sweetening process, a hydrotreating process to remove sulfur, nitrogen and oxygen compounds using a catalyst of cobalt, molybdenum and aluminum under high temperature and high pressure by mixing hydrocarbon oil with hydrogen, silica gel, Adsorption processes for removing sulfur, nitrogen, and oxygen compounds using various adsorbents such as alumina gel are widely used.

For example, Korean Patent No. 313,265 discloses a process for producing a petroleum product having improved cetane number and sulfur content so as to be used as a substrate for a fuel ignition engine for compression ignition from a hydrocarbon feedstock through extraction and hydrogenation of a hydrocarbon feedstock. A method is disclosed.

In addition, Korean Patent No. 213,524 discloses an impurity content, ie, propionitrile, by distilling alkanol from a hydrocarbon mixture containing tertiary olefins having 5 to 6 carbon atoms obtained by cracking hydrocarbons, and removing impurities having high boiling points. A method for removing impurities from petroleum products is disclosed.

However, the removal method according to the prior art has a disadvantage in that the overall process is complicated, the processing time is required for a long time, not only economically disadvantageous, but also in efficiency. In particular, since the 1990s, environmental regulations have been sharply strengthened, and recently, ultra-low sulfur fuels containing less than 10 ppm of gasoline and diesel are produced, especially in advanced countries overseas, and 10 ppm of sulfur content in the next 5 to 10 years. Korea's petroleum products and government regulations are followed, and the existing process conditions will be further deepened to remove as much nitrogen and sulfur compounds as the main causes of air pollutants in fuel. Or, there is an urgent need for technology that can be replaced by a more efficient method.

On the other hand, ionic liquid compounds are different depending on the type, but exist as a liquid in a fairly wide temperature range (-100 ~ 300 ℃ or more), characterized by a wide range of dissolving power, non-flammable, non-evaporable and high conductivity In addition, the physical and chemical properties are changed according to the change in the structure of the cation and anion, which has the advantage of optimizing the chemical structure according to the user's use purpose. In particular, the ionic liquid has a higher specific gravity and boiling point than the general organic compound, so that the organic compound and the ionic liquid can be easily separated through phase separation and distillation, thereby replacing the existing organic solvent. And because of its ability to dissolve in a variety of materials, it can be used in catalyst reactions to facilitate recovery and reuse of catalysts, as well as to increase the reactivity, selectivity and safety of catalysts in some catalytic reactions. As a result, the development of new ionic liquids and the application of ionic liquids in various organic synthesis and electrochemical fields including catalysis have been actively conducted worldwide. [JD Holbresy, KR Seddon, Ionic liquids, Clean Products and Process 1 , 223-236, 1999; Tom Welton, Ionic Liquids in Catalysis, Coordination Chemistry Reviews , 2004, 248, 2459-2477; Bernadette M. Quinn, Zhifeng Ding, etc., Novel Electrochemical Studies of Ionic Liquids, Langmuir , 2002, 18, 1734-1174.

Application experiments in petroleum products or refining processes are also underway, but as of early stages of research, they have not reached the level of commercially applicable technology.

Therefore, in the present invention, as a result of various studies to solve the problems of the conventional petroleum refining process as described above, a trace amount of nitrogen compounds and sulfur compounds in the petroleum hydrocarbon fraction by using an ionic liquid spotlighted as an environmentally friendly solvent It has been found that the removal can be performed efficiently through a simple extraction process, and the present invention has been completed based on this.

Accordingly, an object of the present invention is to efficiently remove nitrogen compounds and sulfur compounds in petroleum hydrocarbon fractions using ionic liquids through a more economic process with improved operating conditions and removal efficiency compared to conventional nitrogen and sulfur compounds removal processes. To provide a way.

Method for removing nitrogen compounds and sulfur compounds in the petroleum hydrocarbon fraction using the ionic liquid according to the present invention for achieving the above object:

 (i) C5 to C50 petroleum hydrocarbon fractions produced during the petroleum refining process and containing sulfur compounds, nitrogen compounds or mixtures thereof; and (ii) sulfur compounds, nitrogen compounds or These mixtures are characterized in that they are removed by extraction from the petroleum hydrocarbon fraction layer into the ionic liquid layer.

Preferably, the petroleum hydrocarbon fraction is naphtha, raw kerosene, light gas oil (LGO), heavy gas oil (HCN), produced in an atmospheric distillation column, Atmospheric residue oil, light cycle oil (LCO), heavy catalytic naphtha (HCN), light catalytic naphtha (LCN) and vacuum distillation residue oil produced in heavy oil cracking processes, and It is selected from the group consisting of gasoline, kerosene, boiler kerosene, light oil, heavy oil, and hydrocarbon fraction separated from crude oil.

Preferably, the ionic liquid is one cation selected from imidazolium, pyridinium, pyrazolium, pyrrolidinium derivative represented by Formula 1 and SbF ₆ ⁻ ( ^{_{hexafluoroantimonate), PF 6 - (hexafluorophosphate}} ), BF 4 - (tetrafluoroborate), Cl - (chloride anion), NTF 2 - (bistrifluoromethylsulfonylamide), CF 3 SO 3 - (trifluoromathanesulfonate), CH 3 OSO 3 - (methylsulfate), HOSO ^{_{3 - (hydrogensulfate), CF 3}} CO 2 - (trifluoroacetate), CF 3 (CF 2) 3 CO 2 - (heptafluorobutanoate) is an ion-binding compound, or a mixture thereof, one of the anions selected from the group consisting of a bond.

Wherein R, R ₁ and R ₂ are the same as or different from each other and C _n H _{2n + 1} and n is an integer from 1 to 12.

Preferably, the solvent to oil ratio (SOR) of the ionic liquid and the petroleum hydrocarbon fraction is from 0.01 to 5.

Preferably, the extraction process through the phase separation is repeated two or more times.

Preferably, the extraction process is carried out at a temperature of 0 ~ 300 ℃.

Preferably, further to the mixture is added an acid selected from the group consisting of 0-20% by volume sulfuric acid, hydrochloric acid, nitric acid and C1-C15 carboxylic acid relative to the ionic liquid.

Preferably, the ionic liquid used in the extraction process is separated from the nitrogen compound, sulfur compound or a mixture thereof using an organic solvent, water or a combination thereof and then reused in the extraction process.

Preferably, the ionic liquid used in the extraction process is separated from the nitrogen compound, sulfur compound or a mixture thereof through distillation and then reused in the extraction process.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As described above, the present invention provides a method for efficiently removing nitrogen compounds and sulfur compounds contained in the petroleum hydrocarbon fraction produced by the petroleum refining process through a simple extraction process using an ionic liquid.

Petroleum hydrocarbon fraction used in the present invention includes petroleum refining semi-finished products and products having a carbon number of C5 ~ C50.

The semi-finished petroleum refining process is an intermediate oil of various petroleum products produced in the petroleum refining process, and examples thereof include naphtha, light oil, light gas oil (LGO), heavy gas oil (HCN), and high pressure glass. Light cycle oil (LCO), heavy cracked naphtha (HCN), light cracked naphtha (LCN), and vacuum distillation residues are produced.

In addition, the petroleum product may include, but is not limited to, a hydrocarbon product produced by separating and refining from gasoline, kerosene, boiler kerosene, diesel, heavy oil, and other crude oil.

^{_{, PF 6 - -, BF 4}} - imidazolium, pyridinium, pyrazolium, pyrrolidinium pyridinium one cationic and SbF ₆ chosen in the derivative represented by the general formula (1) ionic liquid to be used as the extraction solvent in the present invention, ^{_{Cl -, NTF 2 -, CF}} 3 SO 3 -, CH 3 OSO 3 -, HOSO 3 -, CF 3 CO 2 - that combines the one anion selected from the group consisting of ^{_{-, CF 3 (CF 2)}} 3 CO 2 Ionic binding compounds or mixtures thereof are included.

Formula 1

Wherein R, R ₁ and R ₂ are the same as or different from each other and C _n H _{2n + 1} and n is an integer from 1 to 12.

Depending on the hydrocarbon length of the alkyl group, the extraction efficiency or recovery loss after the extraction process is somewhat different, and the optimum ionic liquid can be selected according to the hydrocarbon fraction.

On the other hand, the lower the volume ratio of the ionic liquid and the petroleum hydrocarbon fraction, that is, the solvent to oil ratio (SOR), the better the economical efficiency, preferably 0.01-5, more preferably 0.01-1. It is good to be. At this time, if the treatment ratio is too low, the treatment efficiency is bad, if too high, there is a disadvantage that the layer separation rate is slow and the cost increases.

In addition, the mixing time of the extraction process may be carried out in 10 seconds or more, preferably, after sufficient mixing for a few minutes (minute) it is good to perform a layer separation process. On the other hand, the delamination tends to occur more quickly as the specific gravity of the petroleum fraction is lower, for example, light gas oil (LGO) is preferably left for about 10 to 50 minutes to induce complete delamination.

The extraction process through the phase separation is preferably repeated one or more times in view of increasing the removal efficiency of nitrogen compounds and sulfur compounds.

On the other hand, the extraction process may be carried out at a temperature between 0 ~ 300 ℃, preferably it is carried out at 20 ~ 150 ℃. If the temperature of the extraction process is too low, the delamination is slow and not clean, if too high, the petroleum semi-finished product is likely to evaporate.

In addition, in order to increase the extraction and removal efficiency of nitrogen compounds and sulfur compounds, a carboxyl composed of inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, and C1 to C15 such as Formic Acid, Acetic Acid, Propionic Acid, etc. An acid selected from the group consisting of acids can be added and used as an extraction solvent, and the amount of the acid is preferably 0 to 20% by volume, more preferably 0.01 to 5% by volume, in terms of economic efficiency and efficiency. Here, as the amount of the above-mentioned acid is increased, the reactivity of the hydrocarbon fraction and the acid may increase, thereby reducing the recovery rate of the hydrocarbon fraction.

Therefore, as described above, the extraction / removal efficiency of the nitrogen compound and the sulfur compound may vary depending on the treatment ratio, extraction temperature, extraction time, and acid addition amount of the ionic liquid. Therefore, appropriate conditions may be determined according to the characteristics of the oil to be treated. Can be selected to maximize efficiency.

On the other hand, the ionic liquid used for the extraction of nitrogen compounds and sulfur compounds in the petroleum hydrocarbon fraction is a reverse extraction process using an organic solvent, such as hexane, benzene, ether, water or a combination thereof Alternatively, the nitrogen compound and the sulfur compound may be separated from the ionic liquid through a distillation process and then reused in the extraction process.

The extraction process of the nitrogen compound and the sulfur compound of the present invention described above will be described with light gas oil as an example.

1 is a process flow diagram schematically showing a process of extracting and removing nitrogen compounds and sulfur compounds in light gas oil as an application example of the present invention.

First, the mixed light gas oil (LGO) separated from the atmospheric distillation process is mixed at a predetermined ratio in a mixing unit 1 so that the ionic liquid is sufficiently in contact, and then the ionic liquid and the ionic liquid are separated in a separation unit 2. LGO will let the separation occur due to the specific gravity difference.

Then, the LGO in the upper layer separated therefrom is produced through the hydrotreating unit (3) after the hydrotreating unit (3) and the final hydrodesulfurization process in the final stage, and the lower ionic liquid is produced. After the transfer to the regeneration unit (4), the nitrogen and sulfur compounds (a) extracted from the LGO by using a regeneration solvent is separated and the regenerated ionic liquid (b) is put into the extraction process again.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

Example 1

Removal of Nitrogen / Sulfur Compounds from Light Gas Oil (LGO)

First, the total nitrogen and sulfur content of the raw-LGO (raw-LGO) from the atmospheric distillation process was measured using an analytical equipment. Then, 10 ml of 1-butyl-3-methylimidazolium hexafluoroantimonate was added as a ionic liquid to a 100 ml measuring cylinder, and 0.4 ml of sulfuric acid and 40 ml of raw material-LGO were added thereto. These mixtures were shaken up and down for 10 minutes to mix, and then allowed to stand for at least 10 minutes to completely separate the layers. Then, the upper raw material-LGO was separated and the residual amounts of nitrogen and sulfur compounds remaining therein were measured. As a result of the test, the raw material-LGO contained 126 ppm of nitrogen before the ionic liquid was treated, but after extraction with the ionic liquid, the nitrogen content was reduced to 3.6 ppm, about 97%, and the sulfur content was 12,810 ppm from 13,860 ppm. , About 7.6%.

Example 2

Removal of Nitrogen / Sulfur Compounds from Heavily Degraded Naphtha (HCN) 1

20 ml of deuterated naphtha, one of the decomposition components of atmospheric pressure residue, and 20 ml of 3-butyl-1-methylimidazolium hexafluoroantimonate as an ionic liquid were added to the mixture, and the mixture was stirred until it was sufficiently mixed. As a result of analyzing the nitrogen content of HCN before and after extraction of the upper ionic liquid obtained after separation, the nitrogen content decreased from 375ppm to 60ppm, about 84%, and the sulfur content from 2,093ppm to 1,528ppm, about 27% Decreased.

Example 3

Removal of Nitrogen / Sulfur Compounds from Heavily Degraded Naphtha (HCN) 2

As the ionic liquid, 3-hexyl-1-methylimidazolium hexafluoroantimonate was carried out in the same manner as in Example 2, and the nitrogen content contained in the HCN of the upper layer separated through the extraction process was measured. It was lowered from 375ppm to 34ppm (91% reduction), and the sulfur content was removed from 2,093ppm to 1,174ppm (44% reduction) to remove nitrogen and sulfur components.

Example 4

Removal of Nitrogen / Sulfur Compounds from Heavily Degraded Naphtha (HCN) 3

As the ionic liquid, 3-octyl-1-methylimidazolium hexafluoroantimonate was used in the same manner as in Example 2 to measure the nitrogen content in the HCN of the upper layer separated through the extraction process. It was lowered from 375ppm to 52ppm (86% reduction), and the sulfur content was removed from 2,093ppm to 1,359ppm (35% reduction) to remove nitrogen and sulfur components.

Example 5

Removal of nitrogen / sulfur compounds in light cycle oil (LCO) 1

20 ml of light cycle oil, which is a decomposition component of atmospheric pressure residue, and 20 ml of 3-butyl-1-methylimidazolium hexafluoroantimonate, which is an ionic liquid, are stirred to a sufficient mixture, and then allowed to stand to separate layers. As a result of analyzing the nitrogen and sulfur content of the upper HCN obtained from this, the nitrogen content was reduced from 1,565ppm to 219ppm, about 86%, and the sulfur content was reduced from 6,855ppm to 5,347ppm, about 22%.

Example 6

Removal of Nitrogen / Sulfur Compounds in Light Cycle Oil (LCO) 2

As the ionic liquid, 3-hexyl-1-methylimidazolium hexafluoroantimonate was carried out in the same manner as in Example 5 to measure the nitrogen content contained in the LCO of the upper layer separated through the extraction process. The nitrogen and sulfur components were removed from 1,565 ppm to 152 ppm (90% reduction) and from 6,855 ppm to 3,750 ppm (45% reduction).

Example 7

Removal of Nitrogen / Sulfur Compounds in Light Cycle Oil (LCO) 3

As the ionic liquid, 3-octyl-1-methylimidazolium hexafluoroantimonate was carried out in the same manner as in Example 5 to measure the nitrogen content contained in the LCO of the upper layer separated through the extraction process. The nitrogen and sulfur components were removed from 1,565 ppm to 103 ppm (93% reduction) and from 6,855 ppm to 4,190 ppm (39% reduction).

Example 8

Changes in Removal Efficiency of Nitrogen / Sulfur Compounds According to Treatment Ratio and Sulfuric Acid Addition

The content of nitrogen and sulfur contained in LGO was changed in the same manner as in Example 1 except that sulfuric acid injection amount and solvent to oil ratio (SOR) were changed as shown in Table 1 below. After each measurement, the results are shown in Table 1 below. As can be seen from Table 1, it can be seen that the removal rate of nitrogen and sulfur compounds increases as the liquid treatment ratio and sulfuric acid addition amount are higher.

SOR ^A Sulfuric acid addition amount ^B (%) Nitrogen removal rate (%) Sulfur removal rate (%) 0.25 0.0 31.0 5.4 0.25 2.0 93.0 5.3 0.25 4.0 97.2 7.6 0.50 0.0 59.7 5.6 0.50 2.7 99.7 9.0 0.50 5.3 100.0 17.6 1.0 0.0 73.5 5.7 1.0 2.0 100.0 11.8 1.0 4.0 98.8 20.5 2.0 0.0 82.7 14.7

A. SOR: Volume ratio of ionic solvent and oil

B. Sulfuric acid addition amount:% by volume based on ionic liquid

Example 9

Changes in Removal Efficiency of Nitrogen / Sulfur Compounds by Repeated Extraction

Repeat the extraction process by mixing the raw material-LGO with 1-butyl-3-methylimidazolium hexafluoroantimonate in a 1: 1 ratio, and observed the nitrogen and sulfur contents of the raw material-LGO according to the number of extraction. One result is shown in Table 2 below. No sulfuric acid was added in this experiment. By repeatedly treating the ionic liquid as shown in Table 2, it is possible to increase the removal efficiency of nitrogen compounds and sulfur compounds from the hydrocarbon fraction.

Processing count Nitrogen content of raw material-LGO, ppm Nitrogen removal rate (%) Raw material-sulfur content of LGO, ppm Sulfur removal rate (%) 0 300 13,853 One 57 72.9 12,551 9.4 2 29 86.1 - - 3 17 91.9 11,153 19.5 4 10 95.1 10,022 27.6 5 7 96.6 9,281 33.0

As described above, according to the present invention, nitrogen and sulfur compounds are removed in a very simple manner compared to the conventional process by efficiently removing the trace nitrogen compounds and sulfur compounds contained in the petroleum hydrocarbon fraction through an extraction process using an ionic liquid. Can be removed effectively. In addition, the method according to the present invention is expected to be very useful commercially as an economical separation and purification process through a simple extraction process.

Claims (9)

(i) C5 to C50 petroleum hydrocarbon fractions produced during the petroleum refining process and containing sulfur compounds, nitrogen compounds or mixtures thereof; and (ii) sulfur compounds, nitrogen compounds or A method for removing nitrogen compounds and sulfur compounds in petroleum hydrocarbon fraction using an ionic liquid, characterized in that the mixture is extracted from the petroleum hydrocarbon fraction layer into an ionic liquid layer. According to claim 1, The petroleum hydrocarbon fraction is naphtha (Raw-kerosene), light gas oil (LGA), heavy gas oil (HCN) produced in an atmospheric distillation column ), Atmospheric residue oil, and light cycle oil (LCO), heavy catalytic naphtha (HCN), light catalytic naphtha (LCN) and vacuum distillation residues produced in heavy oil cracking processes. And a hydrocarbon fraction which is separated and purified from gasoline, kerosene, boiler kerosene, diesel, heavy oil, and crude oil. The ionic liquid of claim 1, wherein the ionic liquid is one cation selected from imidazolium, pyridinium, pyrazolium, and pyrrolidinium derivatives represented by Chemical Formula 1 below. ^{_{6 - (hexafluoroantimonate), PF 6}} - (hexafluorophosphate), BF 4 - (tetrafluoroborate), Cl - (chloride anion), NTF 2 - (bistrifluoromethylsulfonylamide), CF 3 SO 3 - (trifluoromathanesulfonate), CH 3 OSO 3 - (methylsulfate ^{_{), HOSO 3 - (hydrogensulfate)}} , CF 3 CO 2 - (trifluoroacetate), CF 3 (CF 2) 3 CO 2 - (heptafluorobutanoate) the ionic bonds are bonded one anion selected from the group consisting of compounds or mixtures thereof Method characterized in that: Formula 1

Wherein R, R ₁ and R ₂ are the same as or different from each other and C _n H _{2n + 1} and n is an integer from 1 to 12. The method of claim 1, wherein the solvent to oil (SOR) ratio of the ionic liquid and the petroleum hydrocarbon fraction is 0.01 to 5. The method of claim 1, wherein the extraction through phase separation is repeated two or more times. The method of claim 1, wherein the extraction process is carried out at a temperature of 0 ~ 300 ℃. The method of claim 1, further comprising adding an acid selected from the group consisting of 0-20% by volume sulfuric acid, hydrochloric acid, nitric acid, and C1-C15 carboxylic acid to the ionic liquid. The method of claim 1, wherein the ionic liquid used in the extraction process is separated from the nitrogen compound, sulfur compound or a mixture thereof using an organic solvent, water or a combination thereof, and then reused in the extraction process. Way. The method of claim 1, wherein the ionic liquid used in the extraction process is separated from the nitrogen compound, sulfur compound or a mixture thereof through distillation, and then reused in the extraction process.

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