KR20030075216A - Method for removing nitrogen compounds from unconverted oil of fuels hydrocracker and its distillate oil under vacuum - Google Patents

Abstract

PURPOSE: Provided are an un-conversed oil from hydrogenation process of fuel oil and a method for removal of nitrogen compound from fractions by vacuum distillation of the un-conversed oil and to produce high quality and heavy lubricant base oil source. CONSTITUTION: The process comprises a first vacuum distillation step(R1); a first hydrogenation step(R2); a series of fractional distillation step(Fs); a second vacuum distillation step(V2); and a nitrogen removal step(P1). The first step(R1) is for removing asphalt from residual oil. The first hydrogenation step(R2) is to remove impurities from the de-asphalt oil from the first step(R1). The fractional distillation step(Fs) separates oil products and the un-conversed oil. The second vacuum distillation step(V2) is to produce high quality and heavy lubricant base oil source and the un-conversed oil residual. The last step(P1) is for removing nitrogen compounds by adsorption out of the lubricant base oil source.

Description

Method for removing nitrogen compounds from unconverted oil of fuels hydrocracker and its distillate oil under vacuum}

The present invention relates to a method for removing nitrogen compounds from unconverted oil in a fuel oil hydrocracking process and reduced pressure distillation fraction fraction thereof, and more specifically, a mixture of reduced pressure gas oil (VGO) and deasphalted oil (DAO). The present invention relates to a method for removing nitrogen compounds from unconverted oil (UCO) generated in a fuel oil hydrocracking process and a high or heavy lubricating base oil feedstock thereof.

Representative processes for producing lube base oil feedstocks are dearomatic processes and dewaxing processes. Depending on the nature of the lubricating base oil feedstock, both of these processes may be used or only one of them may be used, using unconverted oil (UCO) produced in the hydrocracking process (R2) of vacuum gas oil (VGO) as a raw material. This is a representative example of using a dewaxing process.

The type of the dewaxing process is subdivided into a method of using a solvent extraction method and a method of using a catalytic reaction process. Recently, a catalytic reaction process having a high yield and a large improvement in properties is mainly used. Since the catalysts used in the dewaxing catalytic reaction process vary greatly depending on the content of nitrogen and sulfur compounds, it is common to limit the content of these compounds in unconverted oil (UCO), especially the content of nitrogen compounds is the most important constraint. Acts as For this reason, the operating conditions of the hydrocracking process for producing unconverted oil (UCO) or the properties of the input raw materials are restricted.

Meanwhile, in order to minimize the amount of heavy oil produced per unit crude oil, a lot of solvent deasphalting apparatus (SDA) is used. The deasphalting oil (DAO) produced therefrom is mixed with a reduced pressure gas oil (VGO) to be subjected to hydrocracking process. There is a way to do it. Since deasphalted oil (DAO) is inferior in properties to that of vacuum gas (VGO), as shown in Table 1 below, only non-converted gas (VGO) of unconverted oil (UCO) produced by hydrocracking these mixtures is used. It is worse than the treatment, and the trend becomes more pronounced when the deasphalted oil (DAO) ratio is increased.

Kinds VGO DAO UCO produced by processing VGO UCO produced by mixing VGO and DAO Sulfur content, wt% 2.95 3.9 0.0009 0.015 Nitrogen content, ppm 900 3,100 4 23 Nickel content, ppm <1 8.1 <1 <1 Vanadium content, ppm <1 26.5 <1 <1 Residual carbon content, wt% 0.4 10.2 - -

Therefore, in the case of a process using vacuum gas oil (VGO) and deasphalted oil (DAO) to obtain a high and heavy lubricating base oil feedstock, it is necessary to reduce a large amount of nitrogen content.

Meanwhile, US Patent No. 4,846,962 discloses a method of selectively removing BNC from solvent extract oil by adsorbing BNC (basic nitrogen compound) using an acidic polar adsorbent to remove basic nitrogen compound to improve oxidation stability of lubricant base oil. This is described, and there is a clear difference between the present invention and the material to be applied, the field of application and the effects of the application.

Accordingly, it is an object of the present invention to reduce the catalytic activity and lifespan used in the lubricating base oil manufacturing process in the process using reduced pressure gas oil (VGO) and deasphalted oil (DAO) as raw materials to obtain high and heavy lubricating base oil feedstocks. The present invention provides a method for eliminating nitrogen compounds, which are greatly shortened poisoning substances, diversifying lubricating base oil feedstocks, reducing severity of lubricating base oil manufacturing processes, and improving the quality of lubricating base oils.

Adsorption removal method of the nitrogen compound according to the present invention for achieving the above object, by distilling the atmospheric residue oil in the first vacuum distillation step (V1) to separate the vacuum gas oil and vacuum residue oil, the vacuum gas oil directly The depressurized residue oil is supplied to a solvent deasphalting apparatus (SDA) to obtain deasphalted oil from which asphalt and impurities are removed, and the deasphalted oil obtained is subjected to a dehydrogenation process together with the decompressed gas oil. Feeding to R1; Hydrogenation to remove impurities from the vacuum gas oil and deasphalted oil supplied to the hydroprocessing process (R1), and then, supplied to the hydrocracking process (R2) to obtain hard and heavy hydrocarbons; Applying the light and heavy hydrocarbons to a series of fractional distillation processes (Fs) to separate oil products and unconverted oil; Supplying all or part of the unconverted oil to a second vacuum distillation process (V2) to obtain a high-quality and heavy lubricating base oil feedstock having a predetermined viscosity grade, and remaining unconverted oil; In the method for producing a high-grade and heavy lubricating base oil feedstock using the unconverted oil of the fuel oil hydrocracking process comprising the step of injecting the lubricating base oil feedstock into the dewaxing process and stabilization process, comprising:

Supplying the unconverted oil supplied from the fractional distillation process (Fs) to the second reduced pressure distillation process (V2) or the high and heavy lubricant base oil feedstock produced in the second reduced pressure distillation process (V2) to the denitrification reaction process (P1). It is characterized by.

1 is a process for removing nitrogen compounds from the unconverted oil of the fuel oil hydrocracking process according to the present invention.

2 is a process for removing nitrogen compounds from the vacuum distillation fraction fraction of unconverted fuel oil hydrocracking process according to the present invention.

Figure 3 is a graph showing the removal of nitrogen compounds from unconverted oil (UCO) using a novel adsorbent and a regenerated adsorbent according to one embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

DAO: Deasphalted Oil, VGO: Decompressed Gas Oil

UCO: Unconverted oil, AR: Pressure residue

VR: vacuum residue, V1: first vacuum distillation process

V2: second vacuum distillation step, SDA: solvent deasphalting step

R1: hydroprocessing reaction process, R2: hydrocracking reaction process

R3: dewaxing process, Fs: fractional distillation process

P1: Denitrification Process

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

1 is a process diagram of an example of removing nitrogen compounds from the unconverted oil of the fuel oil hydrocracking process according to the present invention, Figure 2 is a nitrogen compound from the vacuum distillation fraction of the unconverted oil of fuel oil hydrocracking process according to the present invention. This is an example of a process chart.

As can be seen from FIG. 1 and FIG. 2, a process for producing high and heavy lubricating base oil feedstocks using unconverted oil (UCO) in a fuel oil hydrocracking process according to the invention involves the following steps.

a) Distillation of atmospheric pressure residue oil in the first vacuum distillation process (V1) to separate the vacuum gas oil and vacuum residue oil, the vacuum gas oil is directly supplied to the hydrogenation process (R1), the vacuum residue oil is a solvent Supplying to the deasphalting apparatus (SDA) to obtain deasphalting oil from which asphalt and impurities have been removed, and supplying the deasphalting oil thus obtained to the hydroprocessing process (R1) together with the reduced pressure gas oil;

b) hydroprocessing to remove impurities from the vacuum gas oil and deasphalted oil supplied to the hydroprocessing process (R1), and then feeding the hydrocracking process (R2) to obtain hard and heavy hydrocarbons;

c) applying the light and heavy hydrocarbons to a series of fractional distillation processes (Fs) to separate the oil product and unconverted oil;

d) supplying all or part of the unconverted oil to the second vacuum distillation process (V2) to obtain a high and heavy lubricating base oil feedstock having a predetermined viscosity grade, and remaining unconverted oil; And

e) introducing the lubricating base oil feedstock into the dewaxing process and stabilization process.

In addition, the remaining unconverted oil not supplied to the second distillation distillation process (V2) and the remaining amount of unconverted oil obtained in the second distillation distillation process (V2) are separated into the hydrocracking reaction process (R2). By recycling, the entire process is either in recycle mode or discharged out of the process for use as fuel oil blend fraction and then in once-through mode. Accordingly, the unconverted oil recycled from the second reduced pressure distillation process (V2) to the hydrocracking reaction process (R2) except for the flow rate of the final residue oil discharged for use as a lubricating base oil feedstock and fuel oil blending oil. The remaining unconverted oil recycled from the fractional distillation process (Fs) to the hydrocracking reaction process (R2) becomes the remainder except for the discharged amount for use as a fuel oil mixture fraction. In other words, if all are discharged to the fuel oil blending fraction is to proceed in a single pass mode without the amount of recycle.

In addition, the hydroprocessing process (R1) and hydrocracking process (R2) may be variously configured in one-stage or two-stage.

Details of other processes are filed by the applicant of Korean Patent Application No. 2002-12394.

In the present invention, the most important feature is to supply the high-quality and heavy lubricating base oil feedstock, which is unconverted oil (UCO) of the fuel oil hydrocracking process or its reduced-pressure fraction fraction, to the denitrification process (P1) to adsorb and remove nitrogen compounds to purify it. To lower the nitrogen compound content of the prepared product. That is, as shown in Figure 1, the unconverted oil supplied to the second vacuum distillation step (V2) in the fractional distillation step (Fs) is supplied to the denitrification step (P1) to adsorb or remove nitrogen compounds, or As shown in FIG. 2, the high and heavy lubricating base oil feedstock produced in the second reduced pressure distillation process (V2) may be supplied to the denitrification process (P1) to adsorb and remove nitrogen compounds.

Solvents, methods and conditions that can maintain the performance of the adsorbent through derivation of adsorbents with superior adsorption selectivity in the removal of nitrogen compounds by the adsorption technique in the denitrification step (P1) and evaluation of various adsorbent regeneration methods Screening is another major technical challenge.

Therefore, in the present invention, the denitrification reaction step (P1) is carried out by continuously operating in an alternate continuous one or more adsorption towers filled with an adsorbent having a specific surface area of 100 ~ 1000m ² / g and a pore diameter of 1 ~ 35nm, When the adsorption tower is saturated, the adsorption tower regeneration process is periodically performed using a regeneration solvent. That is, unconverted oil (UCO) or reduced-pressure fractional fraction thereof introduced as a raw material into the denitrification step (P1) is periodically adsorbed in the adsorption column to produce hydrocarbons from which nitrogen compounds have been removed. On the other hand, when the nitrogen compound is saturated in the adsorption tower to increase the nitrogen compound content in the refined product, the regeneration solvent is introduced, and the adsorption tower regeneration process is performed to remove the nitrogen compound adsorbed on the adsorbent.

In addition, to adjust the process pressure and temperature according to the viscosity characteristics of the raw material, in the present invention, the adsorption process is carried out at a temperature of 40 to 250 ℃ and pressure of less than 100 atm, the adsorption tower regeneration process is 40 to 450 When carried out at a temperature of &lt; RTI ID = 0.0 &gt; C &lt; / RTI &gt; and below 500 atm, the viscosity of the raw material is properly adjusted to obtain effective adsorption and adsorption regeneration results.

The adsorbent is selected from at least one selected from the group consisting of silica gel, silica alumina, activated alumina, activated carbon, silica magnesia and zeolite.

In addition, in order to regenerate the adsorption column, a single solvent is directly supplied to the adsorption column, or a gas such as nitrogen, hydrogen, and carbon dioxide is used to remove the purified product remaining in the adsorption column pores, and then the solvent is supplied second to supply the nitrogen compound adsorbed to the adsorbent. It is also possible to use two solvents to remove them. In the case of using the two solvents, there is an advantage that the amount of by-products is smaller than using a single solvent. In addition, a mixture of a solvent and a nitrogen compound, or a mixture of a solvent and a purified product generated during the regeneration process is recovered in the distillation apparatus as a solvent and a nitrogen compound, a solvent and a purified product, respectively.

Regeneration solvents that can be used in the present invention are carbon dioxide, hydrogen, or nitrogen, hydrocarbons having 2 to 10 carbon atoms, pyridines, phenols, ethers including MTBE, ETBE and anisole, ketones including MIBK, and these At least one selected from the group consisting of a mixture may be used.

Therefore, in the process of using vacuum gas oil (VGO) and deasphalted oil (DAO) as raw materials according to the present invention, by removing the nitrogen compound, which is a poisoning substance that greatly shortens the catalyst activity and life used in the lubricating base oil manufacturing process It can alleviate the severity of lube base oil manufacturing process and improve the quality of high and heavy lube base oil feedstock.

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

Example 1

Unconverted oil (UCO) with a nitrogen content of 35 ppm was treated with fresh adsorbent and regenerated adsorbent. Silica gel was used as the adsorbent, and the adsorption temperature was 70 ° C. and the LHSV was ^{1 hr −1} . In addition, after removing the purified product present in the adsorption column pores using 7 atm nitrogen for adsorbent regeneration, the adsorbent was regenerated using MTBE at 10 atm and 70 ° C as a solvent. At this time, the adsorption performance of each adsorbent is shown in FIG. 3, and very good nitrogen compound removal performance was obtained. As can be seen in Figure 3, the adsorption performance curve in the case of using the regenerated adsorbent 5 times and the adsorption performance curve in the case of using the regenerated adsorbent 30 times does not differ significantly, it can be seen that the regeneration performance is very excellent.

Example 2

In order to compare the nitrogen compound removal performance of each adsorbent, a comparative evaluation was performed on various adsorbents. Fix the ratio of unconverted oil (UCO) and adsorbent to 3/1, remove the adsorbent after 2 hours with stirring at 70 ° C, and measure the nitrogen compound content in the remaining unconverted oil (UCO) to compare the removal rate. 2 is shown. As can be seen in Table 2, when comparing the adsorption performance of silica gel 1 and silica gel 2, despite the wide specific surface area of the gel gel 2, the adsorption performance is low and the effect of pore diameter on the adsorption performance is very large. It can be seen that. On the other hand, when comparing the performance of silica gel 2 and activated alumina, the adsorption performance of silica gel 2 having a large specific surface area is excellent even though the pore diameter is similar, indicating that the adsorbent having a large specific surface area is excellent at the similar pore diameter.

absorbent Pore diameter, nm Specific surface area, m ² / g Nitrogen removal rate,% Silica Gel 1 4 to 10 450 95 Silica gel 2 4 to 6.5 550 85 Activated alumina 2 to 6 350 75 Activated carbon 1 to 35 820 65 Silica alumina 3 to 18 450 85 Silica magnesia 3 to 15 380 70 Zeolite One - 75

Example 3

Dewaxing of unconverted unconverted oil (UCO) and untreated unconverted oil (UCO), which had been removed by adsorption, was carried out to investigate the effect of the removal of nitrogen compounds on the activity of dewaxing catalyst, dewaxed product yield and properties. In order to remove nitrogen compounds in unconverted oil (UCO), 100 g of silica gel was charged to the adsorption tower, and unconverted oil (UCO) was flowed at a rate of LHSV1hr ^-1 , at which time the temperature of the adsorption tower was maintained at 75 ° C. Dewaxing reaction of unconverted unconverted oil (UCO) and unconverted unconverted oil (UCO) without nitrogen compound supplies the reactant to the reactor filled with 20 grams of catalyst at the rate of LHSV 1hr ^-1 . It was fixed at 1,000nm / m ³ , the reaction temperature was fixed at 325 ℃ and the reaction pressure was constant at 160 atm. The results thus obtained are shown in Table 3 below. As can be seen in Table 3 below, the relative activity of the dewaxing catalyst, the viscosity index of the dewaxing product, and the yield of the dewaxing product were all greatly improved as the nitrogen content in the unconverted oil (UCO) was removed. Therefore, it can be seen that the application of the present invention, which is a process for removing nitrogen in unconverted oil (UCO), is very effective.

UCO Type UCO Nitrogen Removal UCO Nitrogen content in UCO, ppm 35 2 Dewaxing Catalyst Relative Activity One 3 Viscosity index of dewaxed products 120 135 Yield of dewaxed products 60% 85%

Example 4

In order to compare the regeneration performance of the adsorbent regeneration solvents, when the unconverted oil (UCO) of 200 times the weight of the adsorbent was treated to saturate the nitrogen compound removal ability of the adsorbent, the solvent for regenerating the adsorbent was flowed. The nitrogen compound concentration in the mixture of the solvent and the nitrogen compound flowing out of the adsorption column was continuously measured, and the amount of the solvent flowed until the nitrogen content was lowered to 1 ppm was relatively shown in Table 4 below. As can be seen in Table 4, it can be seen that MTBE (methyl-tert-butyl-ether) has the best adsorbent regeneration performance, MIBK (Methyl isobutyl ketone) and anisole (anisole) of similar levels to MTBE Performance was shown. Ethyl-tert-butyl-ether (ETBE) and phenol exhibited regenerating performance, although somewhat inferior, and toluene showed the same regeneration performance as the solvent in relatively large amounts. However, all of these solvents showed sufficient ability to regenerate the adsorbent to achieve adsorption performance in the next cycle and to maintain it.

Type of solvent toluene MTBE MIBK ETBE Anisol phenol Flow volume, relative volume One 0.3 0.4 0.7 0.5 0.7

Example 5

The raw material mixed with reduced pressure gas oil (VGO) and deasphalted oil (DAO) having the properties shown in Table 1 in a weight ratio of 3: 7 in the hydroprocessing reaction process (R1) 1.2 hours ^- LHSV (Liquid Hourly Space Velocity) ¹ , pressure 13.5Mpa, temperature 401 ° C, HDM, HDS, HDN, HDCCR catalysts treated with a ratio of hydrogen and oil at 1000nL / L, and then recycled unconverted oil (UCO) described below LHSV The ratio of hydrogen and oil was treated in a hydrocracking reaction process (R2) under conditions of 1000 nL / L using 0.4hr ⁻¹ , pressure 13.5Mpa, and temperature 391 ° C. HDC catalyst. In the solvent deasphalting process (SDA), n-pentane was used as the solvent, and the yield of deasphalted oil was 73LV%.

Subsequently, diesel and light products having a boiling point of 350 ° C. or lower were recovered through a conventional separator and a series of fractional distillation processes to obtain unconverted oil (UCO) having the properties shown in Table 1, and 50% of the unconverted oil (UCO). Recycle to the hydrocracking reaction step (R2) and supply the remainder to the denitrification step (P1) as shown in FIG. 1 to adsorb and remove nitrogen compounds and to remove unconverted oil (UCO) from which nitrogen compounds are adsorbed and removed under a second reduced pressure distillation process. Injected into (V2) and distilled under reduced pressure at a column top pressure of 65mmHg, tower top temperature of 90 ° C and tower bottom pressure of 130mmHg, and tower bottom temperature of 345 ° C, the light extract (Light Distillate) 7.0LV%, 100D extract 10LV%, 150D hard Extract 40.0LV%, intermediate extract 6LV%, 500D heavy extract 30.0LV% and the final residue 7LV% and the like.

Of these, only 100D, 150D, and 500D extracts are used as intermediate products, and 80% of the feed amount (the amount of unconverted oil (UCO) supplied to the second vacuum distillation process (V2)) (ie, 100D: 10%, 150D: 40%, 500D : 30%) and the rest (20% of the feed) were combined and recycled to the hydrocracking process (R2). Therefore, the high viscosity index, low volatility, high-grade lubricating base oil feedstocks of 100D and 150D grades as shown in Table 5 were produced, and raw materials of 500D-grade heavy lubricating base oils were produced.

Hard extract 100D extract 150D extract Intermediate extract 500D extract Last Residual Reason API weight 38.9 38.6 37.7 34.0 29.4 18.6 Viscosity, cst @ 100 ℃ 3.4 3.8 5.7 9.0 12.1 35.2 Viscosity index 123 135 152 120 113 67 Pour point, ℃ - 32 35 - 50 One Nitrogen content, ppm One One One 3 3 7

As can be seen from the above examples, in the process using reduced pressure gas oil (VGO) and deasphalted oil (DAO) as raw materials according to the present invention, the catalyst activity and life used in the lubricating base oil manufacturing process is greatly shortened. By removing the nitrogen compound, which is a poisonous substance, the severity of the lubricating base oil manufacturing process can be alleviated and the quality of the high and heavy lubricating base oil feedstock can be improved.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of the present invention will be apparent from the appended claims.

Claims (7)

The atmospheric residue is distilled in the first vacuum distillation process (V1) to separate the vacuum gas oil and the vacuum residue, and the vacuum gas oil is directly supplied to the hydrogenation process (R1), and the vacuum residue is solvent deasphalted. Supplying to the apparatus SDA to obtain deasphalted oil from which asphalt and impurities have been removed, and supplying the deasphalted oil thus obtained to the hydroprocessing process R1 together with the reduced pressure gas oil; Hydrogenation to remove impurities from the vacuum gas oil and deasphalted oil supplied to the hydroprocessing process (R1), and then, supplied to the hydrocracking process (R2) to obtain hard and heavy hydrocarbons; Applying the light and heavy hydrocarbons to a series of fractional distillation processes (Fs) to separate oil products and unconverted oil; Supplying all or part of the unconverted oil to a second vacuum distillation process (V2) to obtain a high-quality and heavy lubricating base oil feedstock having a predetermined viscosity grade, and remaining unconverted oil; And In the method for producing a high and heavy lubricating base oil feedstock using the unconverted oil of the fuel oil hydrocracking process comprising the step of injecting the lubricating base oil feedstock into the dewaxing process and stabilization process, The high-quality and heavy lubricating base oil feedstock produced in the second distillation distillation process (V2) or the unconverted oil supplied to the second distillation distillation process (V2) from the fractional distillation process (Fs) is supplied to the denitrification reaction process (P1) Method of adsorption and removal of nitrogen compounds. According to claim 1, The denitrification step (P1) is the adsorption process is carried out by alternating continuous operation in one or more adsorption towers filled with an adsorbent having a specific surface area of 100 ~ 1000m ² / g and a pore diameter of 1 ~ 35nm, If the adsorption tower is saturated, characterized in that the adsorption column regeneration process using a regeneration solvent. According to claim 2, wherein the adsorption process is carried out at a temperature of 40 to 250 ℃ and a pressure of less than 100 atm, the adsorption tower regeneration process is characterized in that carried out at a temperature of 40 to 450 ℃ and a pressure of less than 500 atmospheres Way. The method of claim 2, wherein the adsorbent is selected from the group consisting of silica gel, silica alumina, activated alumina, activated carbon, silica magnesia and zeolite. The method of claim 2, wherein the regeneration solvent is carbon dioxide, hydrogen, nitrogen, hydrocarbons having 2 to 10 carbon atoms, pyridines, phenols, ethers including MTBE, ETBE and anisole, ketones including MIBK and these At least one selected from the group consisting of a mixture of the method for use. According to claim 1, wherein the remaining unconverted oil that is not supplied to the second vacuum distillation step (V2) in the fractional distillation step (Fs), and the remaining amount of unconverted oil obtained in the second vacuum distillation step (V2) is hydrocracking reaction. Recycle to process (R2) or discharge out of process for use as fuel oil blend fraction. The method according to claim 1, wherein the hydroprocessing process (R1) and the hydrocracking process (R2) are composed of one-stage or two-stage.