CN110655954A - Ultra-deep desulfurization method of residual hydrotreated diesel - Google Patents

Abstract

The present disclosure relates to a method for ultra-deep desulfurization of residual oil hydrogenated diesel, the method comprising the following steps: a. Fractional distillation of residual oil hydrogenated diesel oil is carried out to obtain light fractions and heavy fractions, the cutting points of the light fractions and heavy fractions The temperature is 331-355° C.; b. The light fraction obtained in step a is subjected to hydrodesulfurization treatment to obtain the first part of ultra-low sulfur diesel oil fraction; c. The heavy fraction obtained in step a is subjected to oxidative desulfurization treatment to obtain The second part of the ultra-low sulfur diesel fraction. The method can effectively remove the sulfur-containing compounds in the residual hydrogenated diesel oil, and compared with the prior art, the severity of the diesel hydrogenation device is reduced, the operation time of the diesel hydrogenation device is prolonged, and the oxidant and the extraction process can be reduced at the same time. The dosage of the agent is high, the yield of oil products is high, and it has good economic benefits.

Description

Ultra-deep desulfurization method of residual hydrotreated diesel

technical field

The present disclosure relates to an ultra-deep desulfurization method for residual hydrogenated diesel oil.

Background technique

The exhaust gas emitted by diesel combustion contains a large number of harmful substances such as sulfur oxides (SO _X ), nitrogen oxides (NO _X ) and particulate matter (PM). These substances not only form acid rain in cities and surrounding areas, but also destroy the earth's ozone layer. May also cause human cancer. To reduce the emissions of pollutants such as SO _X , NO _X and PM in vehicle exhaust, it is necessary to reduce not only the sulfur content in diesel fuel, but also the aromatic hydrocarbon content in diesel fuel.

For this reason, diesel standards are becoming more and more stringent worldwide, and the production of environmentally friendly low-sulfur or ultra-low-sulfur diesel has become a common concern of governments and refineries around the world. For diesel with Euro IV emission standard, the sulfur content is required to be less than 50 μg/g; while for diesel with Euro V emission standard, the sulfur content is further reduced to less than 10 μg/g. It can be seen that the development trend of diesel quality worldwide is to continuously reduce the sulfur content of diesel to meet stricter emission regulations.

Residual oil hydrogenated diesel oil is a segment of diesel oil produced in the production process of residual oil hydrogenation unit, and its sulfur content is generally between 50 and 300 μg/g. Although the sulfur content of residual hydrotreated diesel is much lower than that of straight-run diesel, coking diesel and catalytically cracked diesel, the sulfide contained in it is the hydrogen partial pressure of the residual hydrotreating unit above 15MPa, 0.2h ^- The sulfide remaining after hydrogenation at a space velocity of ¹ is difficult to reduce its sulfur content to less than 10 μg/g by passing it into a diesel hydrogenation unit, and it often needs to be mixed with straight-run diesel for processing. But even so, due to the large amount of multi-substituted dibenzothiophenes in the residual hydrotreated diesel, which are difficult to remove sulfides, the operational severity of the diesel hydrotreating unit is significantly increased, which in turn leads to the shortening of the operating cycle of the diesel hydrotreating unit. , the economy deteriorates.

The mechanism of oxidative desulfurization is that the oxygen atom in the oxidant performs electrophilic addition reaction to the sulfur atom in the sulfur-containing compound to produce sulfone or sulfoxide. The more substituents, the stronger the electronic effect, and the easier the sulfur-containing compound is to be oxidized. Therefore, the difficulty of sulfide removal in oxidative desulfurization process is just opposite to that of hydrodesulfurization. Hydrodesulfurization is suitable for removing thiophene and benzothiophene-containing sulfur compounds, and oxidative desulfurization is suitable for removing dibenzothiophene and substituted dibenzothiophene compounds.

At present, many technologies are developed for the oxidative desulfurization of diesel fractions:

CN1412280A discloses the ultrasonic-catalytic-oxidative desulfurization method for producing ultra-low sulfur diesel oil. The method mixes diesel oil, hydrogen peroxide and phase transfer catalyst into an emulsion under the action of ultrasonic waves, thereby oxidizing most of the sulfides in the diesel oil into sulfones Class, and then obtain ultra-low sulfur diesel that meets the national IV emission standard through extraction.

CN1952050B discloses a method for oxidative desulfurization of diesel oil. In this method, diesel raw material is subjected to oxidative desulfurization reaction in the presence of hydrogen peroxide, extractant and inorganic solid catalyst. The continuous operation of fixed bed can be performed at -20～150℃, liquid hourly space velocity 1～50h ^-1 ; Intermittent operation is at -20 to 150°C, and the reaction time is 0.05 to 1.0 hours to realize the production of national V diesel.

Using these two methods to directly carry out oxidative desulfurization treatment of diesel fraction, easily oxidized dibenzothiophene and substituted dibenzothiophene compounds can be effectively converted into sulfones, while the oxidation rate of non-oxidizable thiophenes is higher than that of non-oxidizable thiophenes. slow, resulting in reduced reaction efficiency. In addition, when full-distillate diesel is processed, a large amount of oxidant needs to be consumed, and a large amount of sulfones and sulfoxides are produced. The liquid yield of the product is low, and a large amount of extractant consumes a large amount of energy in the regeneration process, and the process economy is poor. In addition, when hydrogen peroxide is used as the oxidant, the compatibility of the oxidant and diesel oil is poor, and the oxidation reaction efficiency is low. Using ultrasonic waves to emulsify the oil phase and hydrogen peroxide, the efficiency of the oxidation reaction is enhanced, but the liquid phase separation after the reaction is difficult.

CN200510047498.8 discloses a method for oxidative desulfurization of hydrogenated diesel oil. The method divides the hydrogenated diesel oil into light fractions and heavy fractions according to the cutting point of 250℃～330℃. The light fractions are not processed, and the heavy fractions are oxidized with hydrogen peroxide. After desulfurization and extraction, it is mixed with light fractions to obtain ultra-low sulfur diesel products. The method reduces the distillate oil loss caused by the diesel oxidative desulfurization process to a certain extent, and reduces the consumption of extractant and oxidant. However, its cutting point is relatively light, resulting in a high total amount of heavy distillates, and the proportion of substituted dibenzothiophenes in the heavy distillates is low, not only the oxidation reaction rate is low, but also the total amount of processed heavy distillates is still Too many, there are also problems of large loss of distillate oil and large amount of extractant and oxidant.

SUMMARY OF THE INVENTION

The purpose of the present disclosure is to provide an ultra-deep desulfurization method for residual oil hydrogenated diesel oil, which can effectively remove sulfur-containing compounds in residual oil hydrogenated diesel oil, has high oil product yield, and has good economic benefits.

In order to achieve the above object, the present disclosure provides a method for ultra-deep desulfurization of residual oil hydrogenated diesel oil, the method comprising the following steps:

a. Fractional distillation of the residual hydrogenated diesel oil is carried out to obtain light fractions and heavy fractions, and the cutting point temperature of the light fractions and heavy fractions is 331 to 355°C;

b, the light fraction obtained in step a is subjected to hydrodesulfurization to obtain the first part of ultra-low sulfur diesel oil fraction;

c. The heavy fraction obtained in step a is subjected to oxidative desulfurization treatment to obtain the second part of ultra-low sulfur diesel oil fraction.

Optionally, in step a, the cutting point temperature of the light fraction and the heavy fraction is 335-345°C.

Optionally, in step b, the hydrodesulfurization treatment comprises: contacting the light fraction with a hydrogenation catalyst to carry out a hydrogenation reaction;

The hydrogenation catalyst comprises a carrier and a metal active component supported on the carrier, the carrier is amorphous alumina and/or amorphous silica-alumina, and the metal active component is a VIB group non-precious metal and/or Group VIII non-precious metal, the VIB group non-precious metal is Mo and/or W, and the VIII group non-precious metal is Ni and/or Co.

Optionally, the conditions of the hydrogenation reaction are: the temperature is 320-420°C, the pressure is 3.0-15.0MPa, the liquid hourly volumetric space velocity is 0.5-6.0h ^-1 , and the hydrogen-to-oil volume ratio is 100-1000Nm ³ /m ³ .

Optionally, in step c, the oxidative desulfurization treatment includes: contacting the heavy fraction with a mixture containing an oxidant and an acidic auxiliary to carry out an oxidative desulfurization reaction, and separating the reacted material to remove sulfones and/or sulfones. sulfone compounds to obtain the second part of ultra-low sulfur diesel fraction.

Optionally, the oxidant is a 25-35 wt% aqueous hydrogen peroxide solution, and the molar ratio of the oxidant to the sulfur in the heavy fraction is (1-10):1;

The acid auxiliary agent is at least one selected from formic acid, acetic acid and acetic anhydride, and the molar ratio of the acid auxiliary agent to the sulfur in the heavy fraction is (0.5-5):1.

Optionally, the oxidative desulfurization reaction is carried out in a microchannel reactor, and the microchannel reactor has multiple groups of feed channels, each of which includes a first feed channel and a second feed channel. A feed channel, the first feed channel and the second feed channel converge and communicate with a micro-reaction channel; the heavy fractions are fed from the first feed channel, and the oxidant and acidic auxiliary-containing The mixture is fed from the second feed channel; the smallest dimension of the micro-reaction channel is each 0.1 mm to 2 mm in size, and the next smallest dimension is each 0.5 mm to 10 mm in size;

The reaction conditions of the oxidative desulfurization reaction include: the temperature is 30-80° C., preferably 40-60° C.; the residence time is 0.5-10 min, preferably 1-8 min.

Optionally, the residual hydrogenated diesel is a diesel fraction with a distillation range of 160-390° C. produced by the residual hydrogenation process, and the sulfur content of the residual hydrogenated diesel is 50 to 2000 μg/g.

Optionally, the method further includes: in step b, mixing the light fraction with an externally produced diesel fraction for the hydrodesulfurization treatment, and the externally produced diesel fraction is derived from a straight-run diesel process, a coking diesel process or a catalytic process. The process of cracking diesel, or a combination of two or three of them, produces a diesel fraction with a distillation range of 160-390°C.

Optionally, the method further includes the step of mixing the first part of the ultra-low sulfur diesel fraction obtained in step b and the second part of the ultra-low sulfur diesel fraction obtained in step c.

Through the above technical solutions, the present disclosure fractionates the residual hydrogenated diesel oil at a higher cutting point temperature, and the total amount of obtained light fractions is relatively large, and the total amount of heavy fractions is relatively small. In this way, on the one hand, more light fractions can be hydrodesulfurized at lower severity to produce ultra-low sulfur diesel, which can not only improve product yield, but also significantly reduce process operating costs; on the other hand, heavy fractions are subjected to oxidative desulfurization. The reaction time is short, the consumption of oxidant and catalyst is small, and the amount of adsorbent or extractant required for further product separation is small, and the effects of improving product yield and reducing cost are achieved at the same time. The method of the present disclosure can effectively remove sulfur-containing compounds in the residual hydrogenated diesel oil, and the obtained ultra-low-sulfur diesel product can meet the national V emission index, and has high yield and good economic benefits.

Other features and advantages of the present disclosure will be described in detail in the detailed description that follows.

Detailed ways

Specific embodiments of the present disclosure will be described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, but not to limit the present disclosure.

A method for ultra-deep desulfurization of residual oil hydrogenated diesel oil, characterized in that the method comprises the following steps:

a. Fractional distillation of the residual hydrogenated diesel oil is carried out to obtain light fractions and heavy fractions, and the cutting point temperature of the light fractions and heavy fractions is 331 to 355°C;

b, the light fraction obtained in step a is subjected to hydrodesulfurization to obtain the first part of ultra-low sulfur diesel oil fraction;

c. The heavy fraction obtained in step a is subjected to oxidative desulfurization treatment to obtain the second part of ultra-low sulfur diesel oil fraction.

In the present disclosure, the residual hydrogenated diesel oil is fractionated at a higher cutting point temperature, and the total amount of obtained light fractions is relatively large, and the total amount of heavy fractions is relatively small. In this way, on the one hand, more light fractions can be hydrodesulfurized at lower severity to produce ultra-low sulfur diesel, which can not only improve product yield, but also significantly reduce process operating costs; on the other hand, heavy fractions are subjected to oxidative desulfurization. The reaction time is short, the consumption of oxidant and catalyst is small, and the amount of adsorbent or extractant required for further product separation is small, and the effects of improving product yield and reducing cost are achieved at the same time.

The method of the present disclosure is suitable for diesel distillate oil produced by various residual oil hydrogenation processes, such as diesel distillate oil produced by processes such as fixed bed residual oil hydrogenated diesel oil, suspended bed residual oil hydrogenated diesel oil, and ebullated bed residual oil hydrogenated diesel oil. . Specifically, the residual hydrogenated diesel may be a diesel fraction with a distillation range of 160-390° C. produced by the residual hydrogenation process, and the sulfur content of the residual hydrogenated diesel may be 50 to 2000 μg/g.

According to the present disclosure, in order to further improve the product yield and optimize the desulfurization effect, in step a, the cutting point temperature of the light fraction and the heavy fraction may be 335-345°C.

According to the present disclosure, in step b, the meaning of the hydrodesulfurization treatment is well known to those skilled in the art. Specifically, the hydrodesulfurization treatment may include: contacting the light fraction with a hydrogenation catalyst to perform a hydrogenation reaction.

Among them, the hydrogenation catalyst may be a conventional type used for hydrodesulfurization. For example, the hydrogenation catalyst may include a support and a metal active component supported on the support; the support may be amorphous alumina and/or amorphous silica-alumina; the metal active component may be group VIB Non-precious metals and/or non-precious metals of Group VIII, the non-precious metals of Group VIB may be Mo and/or W, and the non-precious metals of Group VIII may be Ni and/or Co. Specifically, based on the dry weight of the hydrogenation catalyst, the hydrogenation catalyst may include 50 to 85 wt % of a support, 1 to 10 wt % of cobalt and/or nickel based on oxides, and 1 to 10 wt % of cobalt and/or nickel based on oxides 5 to 45% by weight of molybdenum and/or tungsten. The hydrogenation catalyst can be prepared by methods in the prior art, or commercially available.

Wherein, the conditions of the hydrogenation reaction may be: the temperature is 320-420°C, the pressure is 3.0-15.0MPa, the liquid hourly volume space velocity is 0.5-6.0h ^-1 , and the hydrogen-oil volume ratio is 100-1000Nm ³ /m ³ .

According to the present disclosure, in step c, the oxidative desulfurization treatment may include: contacting the heavy fraction with a mixture containing an oxidant and an acidic auxiliary for an oxidative desulfurization reaction, and separating the reacted material to remove sulfone compounds and/or Sulfoxide compounds to obtain the second part of ultra-low sulfur diesel fraction.

Wherein, the oxidant is generally an aqueous hydrogen peroxide solution, the concentration of which may be 25-35% by weight, and the molar ratio of the oxidant to the sulfur in the heavy fraction may be (1-10):1.

Wherein, the acid auxiliary agent may be at least one selected from formic acid, acetic acid and acetic anhydride, and the molar ratio of the acid auxiliary agent to the sulfur in the heavy fraction may be (0.5-5):1.

Wherein, the conditions of the oxidative desulfurization reaction may include: the temperature is 30-80° C., and the reaction time is 0.5-80 min.

In order to further improve the product yield and optimize the desulfurization effect, in a preferred embodiment of the present disclosure, the oxidative desulfurization reaction can be performed in a microchannel reactor. Further, the microchannel reactor may have multiple groups of feed channel groups, and each group of the feed channel groups may include a first feed channel and a second feed channel, the first feed channel and the The second feed channel converges and communicates with a micro-reaction channel. The heavy ends may be fed from the first feed channel (or the second feed channel), and the mixture containing the oxidant and the acidic co-agent may be fed from the second feed channel (or the first feed channel) ) feed, the two meet in the micro-reaction channel, mix, and carry out the oxidative desulfurization reaction. The size of the smallest dimension of the micro-reaction channel is each 0.1 mm to 2 mm, and the size of the next smallest dimension is each 0.5 mm to 10 mm. The definitions of the smallest dimension and the next smallest dimension are well known to those skilled in the art. For example, when the cross-sectional shape of the micro-reaction channel is circular, its diameter is the smallest dimension; when the cross-section of the micro-reaction channel is circular When the shape is a rectangle, the width of the rectangle is the smallest dimension, and the length is the second smallest dimension; when the cross-sectional shape of the micro-reaction channel is an ellipse, the short diameter of the ellipse is the smallest dimension, and the long diameter is the second smallest dimension; and many more. The small size of the micro-reaction channel can significantly improve the contact surface between the heavy fraction and the mixture containing oxidant and acidic auxiliary, thereby promoting the oxidative desulfurization reaction and effectively improving the product yield and desulfurization effect. In addition, the first feeding channel and the second feeding channel may be arranged at a certain angle, for example, 60°, 90°, 180° and the like. The number of the feed channel groups can be designed according to actual needs. Through the enhanced mixing effect of the microchannel reactor, the heavy fraction of the oil phase can be fully mixed with the oxidant and acidic auxiliary of the water phase, and the oxidative desulfurization reaction can be completed in a relatively low severity and in a relatively short time. In this preferred embodiment, the reaction conditions for the oxidative desulfurization reaction may include: a temperature of 30-80° C. and a residence time of 0.5-10 min.

After the oxidative desulfurization reaction is completed, the reacted material can be neutralized and washed with lye, and then separated by adsorption or extraction, so as to remove the sulfone compounds and/or sulfoxide compounds produced by the oxidation to obtain The second portion is an ultra-low sulfur diesel fraction. When the extraction method is used for separation, the extraction agent used can be any suitable polar solvent, such as N,N-dimethylformamide, methanol, dimethyl sulfoxide, etc., and the extraction conditions can be: the temperature is 20～40℃, the pressure is 0.1～0.2MPa, and the volume ratio of agent to oil is (0.5～3):1. When the adsorption method is used for separation, the adsorbent can be silica gel, alumina, etc., and the adsorption conditions can be: the temperature is 20-40°C, the pressure is 0.1-0.2MPa, and the diesel volume space velocity is 0.2-0.6h ^-1 .

According to the present disclosure, the method may further include: in step b, the hydrodesulfurization treatment is performed by mixing the light fraction with an external diesel fraction, the external diesel fraction being derived from a straight-run diesel process, a coking diesel process or a The catalytic cracking diesel process, or the diesel fraction with a distillation range of 160-390° C. produced by a combination of two or three of them. In step b, the light fraction is mixed with an external diesel fraction to carry out the hydrodesulfurization The externally produced diesel fraction is a diesel fraction with a distillation range of 160-390°C produced by a straight-run diesel process, a coking diesel process or a catalytically cracked diesel process, or a combination of two or three of them.

According to the present disclosure, the method may further include the step of mixing the first part of the ultra-low sulfur diesel fraction obtained in step b and the second part of the ultra-low sulfur diesel fraction obtained in step c.

The method of the present disclosure can effectively remove sulfur-containing compounds in residual hydrogenated diesel oil, and the obtained ultra-low sulfur diesel product can meet the national V emission index (sulfur content is not higher than 10 μg/g), and has high yield and has good economic benefits.

The following examples will further illustrate the methods provided by the present disclosure, but do not limit the present disclosure accordingly.

In the embodiment and comparative example, the sulfur content of diesel raw materials is measured by XOS company X-ray fluorescence analyzer, and the test method is: ASTM-7039; the sulfur content of diesel products is measured by the EA5000 model instrument produced by Jena company, and the test method is: SH -0689.

The trade name of the hydrogenation catalyst C used in the examples and comparative examples is RS-2100, which is produced by Sinopec Catalyst Branch.

The total yield of diesel product was calculated using the following formula:

Total yield (%) = light fraction mass fraction×hydrodesulfurization yield+heavy fraction mass fraction×oxidative desulfurization yield.

The basic properties of the feedstock oils used in Examples and Comparative Examples are listed in Table 1.

Table 1

raw oil Raw oil A Raw oil B source Fixed Bed Residue Hydrotreated Diesel Slurry Bed Residue Hydrotreated Diesel Density (20℃), g/cm³ 0.8886 0.8580 Sulfur content, μg/g 127 376 Nitrogen content, μg/g 385 2210 Distillation range ASTM D-86, ℃ IBP 206 175 10% 242 221 30% 274 248 50% 290 275 70% 310 305 90% 338 332 FBP 362 352

Example 1

The feedstock oil A is fractionated according to the cutting point temperature of 340° C. to obtain light fractions and heavy fractions, wherein the light fractions account for 89.8% by weight, the sulfur content is 98 μg/g, and the nitrogen content is 305 μg/g; the heavy fractions account for 10.2% by weight , the sulfur content is 382 μg/g, and the nitrogen content is 1089 μg/g.

The above-mentioned light fractions and hydrogen were sent together into a reactor equipped with a hydrogenation catalyst, and contacted with the hydrogenation catalyst to carry out a ^{hydrodesulfurization} reaction. The partial pressure of hydrogen was 6.4 MPa, and the volume ratio of hydrogen to oil was 300 Nm ³ /m ³ . The sulfur content of the liquid product (ie, the first fraction of ultra-low sulfur diesel fraction) in the resulting reactor effluent was 6.8 μg/g, and the hydrodesulfurization yield was 99.9% by weight.

A T-type microchannel reactor with 50 feed channel groups is used, and the first feed channel and the second feed channel of each feed channel group are arranged at 90° and converge and communicate with a micro reaction channel; The size of the smallest dimension of the reaction channel is 0.3 mm, and the size of the next smallest dimension is 1 mm. The above-mentioned heavy fractions are fed from the first feed channel, and the mixture obtained by mixing 30% by weight aqueous hydrogen peroxide solution and formic acid according to a weight ratio of 1:0.5 is fed from the second feed channel, and H ₂ O ₂ is mixed with heavy fractions. The molar ratio of sulfur in the fraction was 2:1, and the molar ratio of formic acid to sulfur in the heavy fraction was 1:1. The temperature in the microchannel reactor was 60 °C and the residence time was 2 min. The effluent of the microchannel reactor was neutralized with 5 wt% sodium hydroxide solution, and the separated oil phase was adsorbed with silica gel (adsorption conditions were: 25°C, pressure 0.1MPa, diesel volume space velocity 0.4h ^-1 ), the sulfur content of the second part of the ultra-low sulfur diesel fraction product finally obtained was 7.1 μg/g, and the oxidative desulfurization yield was 91.8% by weight.

The first part of ultra-low sulfur diesel oil fraction and the second part of ultra-low sulfur diesel oil fraction were mixed to obtain an ultra-low sulfur diesel product with a sulfur content of 6.8 μg/g and a total yield of 99.1% by weight.

Comparative Example 1

This comparative example is used to illustrate the process of directly carrying out hydrodesulfurization treatment instead of fractional distillation of residual hydrogenated diesel oil.

The raw material oil A and hydrogen are sent into a reactor equipped with a hydrogenation catalyst together, and contacted with the hydrogenation catalyst to carry out a hydrodesulfurization reaction. The reaction conditions are as follows: the temperature is 350°C, the volumetric space velocity of the raw material oil is 2.0h ^-1 , The partial pressure of hydrogen was 6.4 MPa, and the volume ratio of hydrogen to oil was 300 Nm ³ /m ³ . The sulfur content of the liquid product in the resulting reactor effluent was 17.2 μg/g, and the hydrodesulfurization yield was 99.9 wt%.

When the reaction temperature was raised to 370° C. and other conditions remained unchanged, the sulfur content of the liquid product in the obtained reactor effluent was 14.6 μg/g, and the hydrodesulfurization yield was 99.5% by weight.

It can be seen from the comparison between Example 1 and Comparative Example 1 that, according to the method of the present disclosure, the light fraction obtained by fractionating the residual hydrodiesel is subjected to hydrodesulfurization treatment, and the obtained product has a lower sulfur content.

Comparative Example 2

This comparative example is used to illustrate the process of directly carrying out oxidative desulfurization treatment instead of fractional distillation of residual hydrogenated diesel oil.

Using the same microchannel reactor as in Example 1, the feedstock oil A was fed from the first feed channel, and the mixture obtained by mixing 30% by weight aqueous hydrogen peroxide solution and formic acid in a weight ratio of 1:0.5 was obtained from the first feed channel. Two feed channels were fed with a ₂ : ₁ molar ratio of H2O2 to sulfur in the heavy fraction and a 1:1 molar ratio of formic acid to sulfur in the heavy fraction. The temperature in the microchannel reactor was 60 °C and the residence time was 2 min. The effluent of the microchannel reactor was neutralized with 5 wt% sodium hydroxide solution, and the separated oil phase was adsorbed with silica gel (adsorption conditions were: 25°C, pressure 0.1MPa, diesel volume space velocity 0.4h ^-1 ), the sulfur content of the finally obtained diesel product was 21.1 μg/g, and the oxidative desulfurization yield was 92.3% by weight.

From the comparison between Example 1 and Comparative Example 2, it can be seen that, according to the method of the present disclosure, the heavy fraction obtained by fractionating the residual hydrodiesel is subjected to oxidative desulfurization treatment, and the sulfur content of the obtained product is lower.

Comparative Example 3

This comparative example is used to illustrate the effect of fractional distillation of residual hydrogenated diesel oil according to the cutting point temperature different from that of the present disclosure.

The feedstock oil A is fractionated according to the cutting point temperature of 325° C. to obtain light fractions and heavy fractions, wherein the light fractions account for 78.0% by weight, the sulfur content is 74 μg/g, and the nitrogen content is 258 μg/g; the heavy fractions account for 22.0% by weight , the sulfur content is 315 μg/g, and the nitrogen content is 835 μg/g.

The above-mentioned light fractions and hydrogen were sent together into a reactor equipped with a hydrogenation catalyst, and contacted with the hydrogenation catalyst to carry out a ^{hydrodesulfurization} reaction. The partial pressure of hydrogen was 6.4 MPa, and the volume ratio of hydrogen to oil was 300 Nm ³ /m ³ . The sulfur content of the liquid product (ie the first part of the diesel fraction) in the resulting reactor effluent was 6.3 μg/g and the hydrodesulfurization yield was 99.9% by weight.

Using the same microchannel reactor as in Example 1, the above-mentioned heavy fractions were fed from the first feed channel, and the mixture obtained by mixing 30% by weight aqueous hydrogen peroxide solution and formic acid in a weight ratio of 1:0.5 was obtained from the first feed channel. Two feed channels were fed with a ₂ : ₁ molar ratio of H2O2 to sulfur in the heavy fraction and a 1:1 molar ratio of formic acid to sulfur in the heavy fraction. The temperature in the microchannel reactor was 60 °C and the residence time was 2 min. The effluent of the microchannel reactor was neutralized with 5 wt% sodium hydroxide solution, and the separated oil phase was adsorbed with silica gel (adsorption conditions were: 25°C, pressure 0.1MPa, diesel volume space velocity 0.4h ^-1 ), the sulfur content of the second diesel fraction finally obtained was 12.1 μg/g, and the oxidative desulfurization yield was 91.9% by weight.

The first part of the diesel fraction and the second part of the diesel fraction were mixed to obtain a diesel product with a sulfur content of 7.6 μg/g and a total yield of 98.1% by weight.

It can be seen from the comparison between Example 1 and Comparative Example 3 that the sulfur content of the product obtained by the method of the present disclosure is lower, and the total yield is higher.

Example 2

The feedstock oil B was fractionated according to the cutting point temperature of 335°C to obtain light fractions and heavy fractions, wherein the light fractions accounted for 88.9% by weight, the sulfur content was 290 μg/g, the nitrogen content was 1525 μg/g; the heavy fractions accounted for 11.1% by weight , the sulfur content is 1064 μg/g, and the nitrogen content is 7690 μg/g.

The above-mentioned light fractions and hydrogen were sent together into a reactor equipped with a hydrogenation catalyst, and contacted with the hydrogenation catalyst to carry out a hydrodesulfurization reaction. The reaction conditions were: the reaction temperature was 350°C, and the volumetric space velocity of the raw oil was 1.5h ^-1 , the partial pressure of hydrogen is 6.4MPa, and the volume ratio of hydrogen to oil is 300Nm ³ /m ³ . The sulfur content of the liquid product (ie, the first fraction of ultra-low sulfur diesel fraction) in the resulting reactor effluent was 7.4 μg/g, and the hydrodesulfurization yield was 99.9% by weight.

Using the same microchannel reactor as in Example 1, the above-mentioned heavy fraction was fed from the first feed channel, and the mixture obtained by mixing 30% by weight aqueous hydrogen peroxide solution and formic acid in a weight ratio of 1:1 was obtained from the first feed channel. The two feed channels were fed with a 3: ₁ molar ratio of H2O2 to sulfur in the heavy fraction and a ₃ :1 molar ratio of formic acid to sulfur in the heavy fraction. The temperature in the microchannel reactor was 50 °C and the residence time was 3 min. The microchannel reactor effluent was neutralized with 5 wt% sodium hydroxide solution, and the oil phase was separated out and extracted with N,N-dimethylformamide (DMF) (extraction conditions: 30 °C, pressure 0.15 MPa, agent-oil ratio 2:1), the sulfur content of the second part of ultra-low sulfur diesel fraction finally obtained was 6.9 μg/g, and the oxidative desulfurization yield was 91.4 wt %.

The first part of the ultra-low sulfur diesel fraction and the second part of the ultra-low sulfur diesel fraction were mixed to obtain an ultra-low sulfur diesel product with a sulfur content of 7.4 μg/g and a total yield of 99.0% by weight.

Comparative Example 4

This comparative example is used to illustrate the process of directly carrying out hydrodesulfurization treatment instead of fractional distillation of residual hydrogenated diesel oil.

The raw material oil B and hydrogen were sent into the reactor equipped with the hydrogenation catalyst together, and contacted with the hydrogenation catalyst to carry out the ^{hydrodesulfurization} reaction. The partial pressure of hydrogen was 6.4 MPa, and the volume ratio of hydrogen to oil was 300 Nm ³ /m ³ . The sulfur content of the liquid product in the resulting reactor effluent was 21.7 μg/g, and the hydrodesulfurization yield was 99.8% by weight.

When the reaction temperature was raised to 370° C. and other conditions remained unchanged, the sulfur content of the liquid product in the obtained reactor effluent was 16.2 μg/g, and the hydrodesulfurization yield was 99.4% by weight.

From the comparison between Example 2 and Comparative Example 4, it can be seen that, according to the method of the present disclosure, the light fraction obtained by fractionating the residual hydrodiesel is subjected to hydrodesulfurization treatment, and the sulfur content of the obtained product is lower.

Comparative Example 5

This comparative example is used to illustrate the process of directly carrying out oxidative desulfurization treatment instead of fractional distillation of residual hydrogenated diesel.

The raw material oil B, 30% by weight aqueous hydrogen peroxide solution and formic acid were passed into a 500mm diameter 500mm tank with an inert solid filler according to the molar ratio of H ₂ O ₂ : formic acid: the sulfur in the raw oil B was 3: 3: 1. The oxidative desulfurization reaction was carried out in the reactor, the temperature of the reactor was 50 ° C, the residence time was 80 min, and the effluent of the reactor was neutralized with 5% by weight of sodium hydroxide solution, and the oil phase N,N-dimethylformamide (DMF) was separated. ) for extraction (extraction conditions are: 30° C., pressure 0.15MPa, agent-oil ratio 2:1), the final obtained diesel product has a sulfur content of 9.8 μg/g, and an oxidative desulfurization yield of 90.1% by weight.

It can be seen from the comparison between Example 2 and Comparative Example 5 that, according to the method of the present disclosure, the heavy fractions obtained by fractionating the residual hydrogenated diesel oil are subjected to oxidative desulfurization treatment in a microchannel reactor, the treatment time is greatly shortened, and the obtained products with lower sulfur content.

Example 3

The feedstock oil A is fractionated according to the cutting point temperature of 340° C. to obtain light fractions and heavy fractions, wherein the light fractions account for 89.8% by weight, the sulfur content is 98 μg/g, and the nitrogen content is 305 μg/g; the heavy fractions account for 10.2% by weight , the sulfur content is 382 μg/g, and the nitrogen content is 1089 μg/g.

The above-mentioned light fractions and hydrogen were sent together into a reactor equipped with a hydrogenation catalyst, and contacted with the hydrogenation catalyst to carry out a ^{hydrodesulfurization} reaction. The partial pressure of hydrogen was 6.4 MPa, and the volume ratio of hydrogen to oil was 300 Nm ³ /m ³ . The sulfur content of the liquid product (ie, the first fraction of ultra-low sulfur diesel fraction) in the resulting reactor effluent was 6.8 μg/g, and the hydrodesulfurization yield was 99.9% by weight.

The above-mentioned heavy fraction, 30% by weight aqueous hydrogen peroxide solution and formic acid were passed into a diameter of 500mm according to H ₂ O ₂ : formic acid: the molar ratio of sulfur in the raw material oil B was 2: 1: 1), and filled with inert solid fillers The reactor carried out oxidative desulfurization reaction, the temperature of the reactor was 60 ° C, the residence time was 30 min, the effluent of the reactor was neutralized with 5% by weight sodium hydroxide solution, and the separated oil phase was adsorbed with silica gel (adsorption conditions were: 25 ℃, the pressure is 0.1MPa, the diesel volume space velocity is 0.4h ^-1 ), the sulfur content of the second ultra-low sulfur diesel fraction finally obtained is 14.8μg/g, and the oxidative desulfurization yield is 90.5% by weight.

The first part of ultra-low sulfur diesel fraction and the second part of ultra-low-sulfur diesel fraction were mixed to obtain an ultra-low-sulfur diesel product with a sulfur content of 7.6 μg/g and a total yield of 98.9% by weight.

Example 4

The feedstock oil B was fractionated according to the cutting point temperature of 335°C to obtain light fractions and heavy fractions, wherein the light fractions accounted for 88.9% by weight, the sulfur content was 290 μg/g, the nitrogen content was 1525 μg/g; the heavy fractions accounted for 11.1% by weight , the sulfur content is 1064 μg/g, and the nitrogen content is 7690 μg/g.

The above-mentioned light fractions and hydrogen were sent together into a reactor equipped with a hydrogenation catalyst, and contacted with the hydrogenation catalyst to carry out a hydrodesulfurization reaction. The reaction conditions were: the reaction temperature was 350°C, and the volumetric space velocity of the raw oil was 1.5h ^-1 , the partial pressure of hydrogen is 6.4MPa, and the volume ratio of hydrogen to oil is 300Nm ³ /m ³ . The sulfur content of the liquid product (ie, the first fraction of ultra-low sulfur diesel fraction) in the resulting reactor effluent was 7.4 μg/g, and the hydrodesulfurization yield was 99.9% by weight.

The above-mentioned heavy fraction, 30% by weight aqueous hydrogen peroxide solution and formic acid were passed into a diameter of 500 mm according to H ₂ O ₂ : formic acid: the molar ratio of sulfur in the raw material oil B was 3:3:1), and filled with inert solid fillers The reactor carried out oxidative desulfurization reaction, the temperature of the reactor was 50 ° C, the residence time was 80 min, and the effluent of the reactor was neutralized with 5% by weight sodium hydroxide solution, and the oil phase N,N-dimethylformamide ( DMF) for extraction (extraction conditions are: 30°C, pressure is 0.15MPa, agent-oil ratio is 2:1), the sulfur content of the second part of the ultra-low sulfur diesel fraction finally obtained is 9.9 μg/g, and the oxidative desulfurization yield is 90.4% by weight.

The first part of the ultra-low sulfur diesel fraction and the second part of the ultra-low sulfur diesel fraction were mixed to obtain an ultra-low sulfur diesel product with a sulfur content of 7.7 μg/g and a total yield of 98.8% by weight.

From the comparison of Example 1-2 and Example 3-4, it can be seen that when the oxidative desulfurization treatment is carried out in the microchannel reactor, not only the treatment time can be shortened, but also the sulfur content of the obtained product is lower, and the total yield is higher. high.

Example 5

The raw oil A is fractionated according to the cutting point temperature of 331°C to obtain light fractions and heavy fractions, wherein the light fractions account for 81.8% by weight, the sulfur content is 78 μg/g, the nitrogen content is 268 μg/g; the heavy fractions account for 18.2% by weight , the sulfur content was 347 μg/g, and the nitrogen content was 911 μg/g.

The above-mentioned light fractions and hydrogen were sent together into a reactor equipped with a hydrogenation catalyst, and contacted with the hydrogenation catalyst to carry out a ^{hydrodesulfurization} reaction. The partial pressure of hydrogen was 6.4 MPa, and the volume ratio of hydrogen to oil was 300 Nm ³ /m ³ . The sulfur content of the liquid product (ie, the first fraction of ultra-low sulfur diesel fraction) in the resulting reactor effluent was 6.3 μg/g, and the hydrodesulfurization yield was 99.9% by weight.

Using the same microchannel reactor as in Example 1, the above-mentioned heavy fractions were fed from the first feed channel, and the mixture obtained by mixing 30% by weight aqueous hydrogen peroxide solution and formic acid in a weight ratio of 1:0.5 was obtained from the first feed channel. Two feed channels were fed with a ₂ : ₁ molar ratio of H2O2 to sulfur in the heavy fraction and a 1:1 molar ratio of formic acid to sulfur in the heavy fraction. The temperature in the microchannel reactor was 60 °C and the residence time was 2 min. The effluent of the microchannel reactor was neutralized with 5 wt% sodium hydroxide solution, and the separated oil phase was adsorbed with silica gel (adsorption conditions were: 25°C, pressure 0.1MPa, diesel volume space velocity 0.4h ^-1 ), the sulfur content of the second part of the ultra-low sulfur diesel fraction product finally obtained was 10.7 μg/g, and the oxidative desulfurization yield was 91.9% by weight.

The first part of ultra-low sulfur diesel oil fraction and the second part of ultra-low sulfur diesel oil fraction were mixed to obtain an ultra-low sulfur diesel product with a sulfur content of 7.1 μg/g and a total yield of 98.4% by weight.

Example 6

The feedstock oil A is fractionated according to the cutting point temperature of 350°C to obtain light fractions and heavy fractions, wherein the light fractions account for 94.5% by weight, the sulfur content is 106 μg/g, the nitrogen content is 327 μg/g; the heavy fractions account for 5.5% by weight , the sulfur content was 488 μg/g, and the nitrogen content was 1381 μg/g.

The above-mentioned light fractions and hydrogen were sent together into a reactor equipped with a hydrogenation catalyst, and contacted with the hydrogenation catalyst to carry out a hydrodesulfurization reaction. The reaction conditions were: the temperature was 360°C, the volumetric space velocity of the raw oil was 2.0h ^-1 , The partial pressure of hydrogen was 6.4 MPa, and the volume ratio of hydrogen to oil was 300 Nm ³ /m ³ . The sulfur content of the liquid product (ie, the first fraction of ultra-low sulfur diesel fraction) in the resulting reactor effluent was 7.2 μg/g, and the hydrodesulfurization yield was 99.9% by weight.

Using the same microchannel reactor as in Example 1, the above-mentioned heavy fractions were fed from the first feed channel, and the mixture obtained by mixing 30% by weight aqueous hydrogen peroxide solution and formic acid in a weight ratio of 1:0.5 was obtained from the first feed channel. Two feed channels were fed with a ₂ : ₁ molar ratio of H2O2 to sulfur in the heavy fraction and a 1:1 molar ratio of formic acid to sulfur in the heavy fraction. The temperature in the microchannel reactor was 60 °C and the residence time was 2 min. The effluent of the microchannel reactor was neutralized with 5 wt% sodium hydroxide solution, and the separated oil phase was adsorbed with silica gel (adsorption conditions were: 25°C, pressure 0.1MPa, diesel volume space velocity 0.4h ^-1 ), the sulfur content of the second part of the ultra-low sulfur diesel fraction product finally obtained was 4.1 μg/g, and the oxidative desulfurization yield was 91.7% by weight.

The first part of ultra-low sulfur diesel oil fraction and the second part of ultra-low sulfur diesel oil fraction were mixed to obtain an ultra-low sulfur diesel product with a sulfur content of 7.0 μg/g and a total yield of 99.4% by weight.

It can be seen from the comparison between Example 1 and Examples 5-6 that when the cutting point temperature is 335-345° C., the sulfur content of the obtained product is lower.

The preferred embodiments of the present disclosure are described above in detail, but the present disclosure is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure. These simple modifications All belong to the protection scope of the present disclosure.

In addition, it should be noted that the various specific technical features described in the above-mentioned specific embodiments can be combined in any suitable manner unless they are inconsistent. In order to avoid unnecessary repetition, the present disclosure provides The combination method will not be specified otherwise.

In addition, the various embodiments of the present disclosure can also be arbitrarily combined, as long as they do not violate the spirit of the present disclosure, they should also be regarded as the contents disclosed in the present disclosure.

Claims (10)

1. an ultra-deep desulfurization method of residual oil hydrogenated diesel oil, is characterized in that, this method may further comprise the steps: a. Fractional distillation of residual hydrogenated diesel oil to obtain light fractions and heavy fractions, and the cutting point temperature of the light fractions and heavy fractions is 331 to 355°C; b, the light fraction obtained in step a is subjected to hydrodesulfurization to obtain the first part of ultra-low sulfur diesel oil fraction; c. The heavy fraction obtained in step a is subjected to oxidative desulfurization treatment to obtain the second part of ultra-low sulfur diesel oil fraction. 2 . The method according to claim 1 , wherein, in step a, the cutting point temperature of the light fraction and the heavy fraction is 335-345° C. 3 . 3. The method according to claim 1, wherein, in step b, the hydrodesulfurization treatment comprises: contacting the light ends with a hydrogenation catalyst to carry out a hydrogenation reaction; The hydrogenation catalyst comprises a carrier and a metal active component supported on the carrier, the carrier is amorphous alumina and/or amorphous silica-alumina, and the metal active component is a VIB group non-precious metal and/or Group VIII non-precious metal, the VIB group non-precious metal is Mo and/or W, and the VIII group non-precious metal is Ni and/or Co. 4. The method according to claim 3, wherein, the conditions of the hydrogenation reaction are: the temperature is 320～420℃, the pressure is 3.0～15.0MPa, the liquid hourly volume space velocity is 0.5～6.0h ^-1 , the hydrogen oil The volume ratio is 100 to 1000 Nm ³ /m ³ . 5. The method according to claim 1, wherein, in step c, the oxidative desulfurization treatment comprises: contacting the heavy fraction with a mixture containing an oxidant and an acid auxiliary to carry out an oxidative desulfurization reaction, and separating the reacted materials The second part of ultra-low sulfur diesel oil fraction is obtained by removing sulfone compounds and/or sulfoxide compounds. 6 . The method according to claim 5 , wherein the oxidizing agent is a 25-35 wt% aqueous hydrogen peroxide solution, and the molar ratio of the oxidizing agent to the sulfur in the heavy fraction is (1-10):1 ; The acid auxiliary agent is at least one selected from formic acid, acetic acid and acetic anhydride, and the molar ratio of the acid auxiliary agent to the sulfur in the heavy fraction is (0.5-5):1. 7. The method according to claim 5, wherein the oxidative desulfurization reaction is carried out in a microchannel reactor, the microchannel reactor has a plurality of sets of feed channel groups, and each set of the feed channel groups comprises a first feed channel and a second feed channel, the first feed channel and the second feed channel converge and communicate with a micro-reaction channel; the heavy fractions are fed from the first feed channel, The mixture containing the oxidant and the acidic auxiliary is fed from the second feed channel; the smallest dimension of the micro-reaction channel is each 0.1mm-2mm, and the next smallest dimension is 0.5mm-10mm; The reaction conditions of the oxidative desulfurization reaction include: the temperature is 30-80° C., preferably 40-60° C.; the residence time is 0.5-10 min, preferably 1-8 min. 8. The method according to claim 1 , wherein the residual oil hydrogenated diesel oil is a diesel fraction with a distillation range of 160-390° C. produced by the residual oil hydrogenation process, and the sulfur content of the residual oil hydrogenated diesel oil is 50～2000μg/g. 9. The method according to claim 1 , wherein the method further comprises: in step b, mixing the light ends with an externally produced diesel oil fraction to carry out the hydrodesulfurization treatment, and the externally produced diesel oil fraction is derived from direct oil. Distillation diesel process, coking diesel process or catalytic cracking diesel process, or a combination of two or three of them produces diesel fractions with a distillation range of 160-390°C. 10. The method according to claim 1, wherein the method further comprises the step of mixing the first part of ultra-low sulfur diesel oil fraction obtained in step b and the second part of ultra-low sulfur diesel oil fraction obtained in step c.