CN103695035B - A kind of combined method of producing super low-sulfur oil - Google Patents

Abstract

A combined method for producing ultra-low sulfur gasoline, gasoline feedstock is fractionated into light fraction gasoline and heavy fraction gasoline, the light fraction gasoline enters the alkali extraction unit, and the heavy fraction gasoline is contacted with a selective hydrodesulfurization catalyst in the first hydrogenation reactor The reaction is carried out, and after being stripped by the intermediate stripping tower, it enters the second hydrogenation reactor to contact with the waste residue hydrogenation catalyst for reaction, and the refined light distillate gasoline is mixed with the hydrogenated heavy distillate gasoline to obtain an ultra-low sulfur gasoline fraction. The invention can process catalytic cracking gasoline with high olefin content, and the total sulfur content of the obtained full-cut gasoline product is less than 10 μg/g, and compared with the full-cut gasoline raw material, the loss of octane number is small, and the loss of RON is less than 1.5 units.

Description

A combined method for producing ultra-low sulfur gasoline

technical field

The invention relates to a method for reducing the sulfur content of gasoline, which is a combination method of two processes of removing sulfur in the absence of hydrogen and refining hydrocarbon oil in the presence of hydrogen.

Background technique

With the enhancement of human environmental protection awareness, people pay more and more attention to the pollution of atmospheric environment caused by harmful substances in automobile exhaust. Countries all over the world have proposed increasingly strict restrictions on the composition of gasoline for vehicles, especially the sulfur content. The European Union has implemented the Euro V emission standard in 2009, requiring the sulfur content of gasoline to be less than 10 μg/g, and plans to implement the more stringent Euro VI standard around 2014. The second and third stages of gasoline standards in California state that the sulfur content in gasoline should not be higher than 30μg/g and 15μg/g, respectively. At the end of 2009, China began to implement the National III gasoline standard (GB 17930-2006) with a sulfur content of no more than 150 μg/g, and will implement the National IV gasoline standard (GB17930-2011) at the end of 2013, requiring that the sulfur content of gasoline should not exceed 50 μg/g. g. In the future, the National V gasoline standard may limit the sulfur content of gasoline to no more than 10 μg/g.

More than 90% of the sulfur in China's finished gasoline comes from catalytic cracking gasoline (FCC gasoline). Therefore, reducing the sulfur content of FCC gasoline is the key to reducing the sulfur content of finished gasoline.

There are usually two technical solutions for reducing the sulfur content of FCC gasoline: catalytic cracking feedstock hydrotreating and catalytic cracking gasoline hydrotreating. The catalytic cracking raw material hydrotreating unit needs to be operated under very harsh conditions of temperature and pressure, and has a large processing capacity, high hydrogen consumption, and high equipment investment and operating costs. If only the hydrotreating of catalytic cracking raw materials is used, the sulfur content of FCC gasoline of some enterprises can be reduced to below 500μg/g or below 150μg/g. However, if the sulfur content of FCC gasoline is to be further reduced to meet the limits of gasoline sulfur content in Euro IV and Euro V emission standards, hydrodesulfurization of FCC gasoline is still required.

When traditional catalysts and processes are used to hydrodesulfurize FCC gasoline, the octane number of gasoline will be greatly lost due to the large hydrogenation saturation of olefins. FCC gasoline selective hydrodesulfurization technology is a technology that reduces the loss of octane number by reducing olefin hydrogenation saturation as much as possible while FCC gasoline is hydrodesulfurized. It is a technology widely developed and applied at home and abroad.

There are many methods for selective hydrodesulfurization of FCC gasoline in the prior art, but most of them are difficult to achieve a product sulfur content of less than 10 μg/g, or when the product sulfur content is less than 10 μg/g, the loss of octane number is relatively large.

EP0940464 proposes a process for catalytic cracking gasoline desulfurization. This method cuts FCC gasoline into three different fractions: light, medium and heavy. The heavy distillate is hydrodesulfurized in the first bed, and the reaction product is mixed with the middle distillate at the outlet of the first bed, and then enters the second bed for hydrodesulfurization. However, the olefin saturation rate in the hydrogenation process of this method is too high, the octane number loss is too large, and the sulfur content of the gasoline product after the patent treatment cannot be less than 10 μg/g.

US5906730 proposes a method for segmental desulfurization of FCC gasoline. The first stage maintains a desulfurization rate of 60-90%. The process conditions are: temperature 200-350°C, pressure 5-30kg/cm ² , liquid hourly space velocity 2-10h ^-1 , hydrogen-to-oil volume ratio 89-534, H ₂ S concentration The control is less than 0.1% by volume. The second stage controls the desulfurization rate to 60~90%. The process conditions are: temperature 200~300℃, pressure 5~15kg/cm ² , liquid hourly space velocity 2~10h ^-1 , hydrogen to oil volume ratio 178~534, H ₂ S concentration Control less than 0.05% by volume. If the second-stage desulfurization still fails to achieve the expected purpose, the outlet effluent of the second-stage desulfurization will continue to be desulfurized, and the process conditions are the same as those of the second-stage desulfurization process. Its examples show that, using this method to hydrotreat the catalytically cracked gasoline fraction with a distillation range of 80-220°C, a sulfur content of 220 μg/g, and an olefin volume fraction of 32%, when the sulfur content of the product is 8 μg/g, the octane number RON loss is 2.6 . If this method is used to process FCC gasoline with high sulfur content and high olefin content, the loss of octane number will be very large.

CN1465668A proposes a method for producing low-sulfur gasoline. The gasoline raw material is cut into light and heavy fractions. The light fraction is demercaptanized by alkali refining. The heavy fraction and hydrogen are contacted with a hydrodesulfurization catalyst to carry out selective hydrodesulfurization reaction. The hydrogenated gasoline fraction is subjected to hydrogenation or non-hydrogenation demercaptanization, and the desulfurized light and heavy fractions are mixed to obtain gasoline products. The method can produce gasoline with a sulfur content lower than 200 μg/g, and the loss of antiknock index ((RON+MON)/2) is less than 2 units. The desulfurization depth of this method is not enough, and gasoline with a sulfur content of less than 10 μg/g cannot be obtained.

CN1478866A proposes a method for gasoline desulfurization. The gasoline raw material is cut into light gasoline fraction and heavy gasoline fraction; the heavy gasoline fraction and hydrogen are contacted with hydrodesulfurization catalyst together to carry out selective hydrodesulfurization reaction, and the reaction effluent is separated by high pressure After the gas phase is separated by the separator, the remaining liquid phase is mixed with new hydrogen and then contacted with the hydrodemercaptan catalyst, and the effluent enters the high-pressure separator and the stabilization tower in turn to obtain qualified products; the hydrogen-rich gas separated from the high-pressure separator passes through the cycle After the compressor is boosted, it returns to the hydrotreating reactor for recycling. The main purpose of the method is to produce gasoline with mercaptan sulfur less than 10 μg/g, and the total sulfur content of the product cannot be less than 10 μg/g.

CN101619234A discloses a method for producing low-sulfur gasoline from light gasoline. The process adopts two-stage hydrogenation technology: the first stage uses a selective hydrodesulfurization catalyst to selectively hydrodesulfurize the gasoline raw material, and the reaction product enters the second stage reactor to contact with the hydrodemercaptan catalyst. Get clean gasoline products. The selective hydrogenation desulfurization catalyst used therein uses alumina as a carrier, molybdenum and cobalt as active components, and simultaneously contains additives potassium and phosphorus. The hydrodemercaptan catalyst used has copper and zinc as main components. The method can produce gasoline with a sulfur content of less than 10 μg/g and a mercaptan sulfur content of less than 5.0 μg/g, and an octane number RON loss of less than 2.0 units. The disadvantage is that this method is only suitable for hydrodesulfurization and sweetening of gasoline with a sulfur content lower than 700 μg/g.

Contents of the invention

On the basis of the prior art, the invention provides a combined method for producing ultra-low sulfur gasoline with a sulfur content less than 10 μg/g.

The technical scheme provided by the invention comprises the following steps:

(1) Fractional distillation of gasoline raw materials into light distillate gasoline and heavy distillate gasoline, where the cut point of light distillate gasoline and heavy distillate gasoline is 50°C to 70°C;

(2) The light distillate gasoline enters the alkali extraction unit, and the mercaptan sulfur is removed through alkali washing and refining to obtain refined light distillate gasoline;

(3) Heavy distillate gasoline and hydrogen enter the first hydrogenation reactor to contact with the selective hydrodesulfurization catalyst for reaction, and the reaction effluent of the first hydrogenation reactor enters the intermediate stripping tower for stripping, and the intermediate stripping The liquid phase stream obtained from the tower enters the second hydrogenation reactor together with the hydrogen, and reacts with the waste residue oil hydrogenation catalyst. The reaction temperature of the second hydrogenation reactor is lower than the reaction temperature of the first hydrogenation reactor.

(4) The reaction effluent of the second hydrogenation reactor is cooled and separated, and the separated liquid phase flow enters the stabilization tower, and the bottom effluent of the stabilization tower is hydrogenated heavy distillate gasoline,

(5) The refined light distillate gasoline obtained in step (2) is mixed with the hydrogenated heavy distillate gasoline obtained in step (4) to obtain an ultra-low sulfur gasoline fraction.

In step (1), the gasoline raw material is cut into light distillate gasoline and heavy distillate gasoline at 50-70°C. Light distillate gasoline contains a large part of olefins and a small part of sulfides, all of which are non-thiophene sulfides. Heavy distillate gasoline contains a large part of sulfides and a small part of olefins. The ratios are 25% to 35% by weight and 65% to 75% by weight of the gasoline feedstock, respectively.

The light distillate gasoline obtained in step (1) enters the alkali extraction unit, and the mercaptan sulfur therein is removed through alkali washing and refining to obtain refined light distillate gasoline.

In step (3), the heavy distillate gasoline obtained in step (1) is mixed with hydrogen and then subjected to two-stage selective hydrodesulfurization. After the heavy distillate gasoline is mixed with hydrogen, it first enters the first hydrogenation reactor and contacts with the selective hydrodesulfurization catalyst. The hydrogen partial pressure is 1.0-4.0MPa, the reaction temperature is 200-400℃, the volume space velocity is 2-8h ^-1 , The selective hydrodesulfurization reaction is carried out under the reaction condition that the volume ratio of hydrogen to oil is 200-1000Nm ³ /m ³ .

The effluent from the first hydrogenation reactor enters the intermediate stripping tower, and the gas phase stream and the liquid phase stream are separated under the action of gas stripping. The gas phase stream is hydrogen-rich gas containing hydrogen sulfide, which is recycled after hydrogen sulfide removal; the liquid phase The stream is mixed with the circulating hydrogen after hydrogen sulfide removal and enters the second ^reactor , where it contacts with the waste residue oil hydrogenation catalyst. The hydrogen Under the reaction conditions of the oil volume ratio of 200-1000Nm ³ /m ³ , the residual non-mercaptan sulfides are removed and the regenerated mercaptans produced by the first-stage hydrogenation are removed at the same time. The stripping medium of the intermediate stripping tower is hydrogen, preferably fresh hydrogen, and the operating condition of the intermediate stripping tower is: pressure 1.0-4.0 MPa. The reaction temperature of the second hydrogenation reactor is 5-50° C. lower than that of the first hydrogenation reactor.

In addition, the present invention can realize the goal of producing low ultra-sulfur gasoline and controlling the minimum loss of octane number by adjusting the cut point of light and heavy fractions and/or the process conditions of the two hydrogenation reactors.

The gasoline raw material is selected from one or more of catalytic cracking gasoline, catalytic cracking gasoline, straight-run gasoline, coker gasoline, pyrolysis gasoline and thermal cracking gasoline. gasoline.

The selective hydrodesulfurization catalyst in the first hydrogenation reactor is a Group VIB non-noble metal catalyst and/or Group VIII non-noble metal catalyst supported on alumina and/or silica-alumina carrier. Preferably, in the selective desulfurization catalyst, the Group VIB non-noble metal is selected from molybdenum and/or tungsten, and the Group VIII non-noble metal is selected from cobalt and/or nickel, calculated as oxides and based on the total weight of the catalyst, this selection The active hydrodesulfurization catalyst contains 5.0% to 20% by weight of molybdenum and/or tungsten, and 2.0% to 10.0% by weight of nickel and/or cobalt.

The preferred preparation method of the selective hydrodesulfurization catalyst is as follows: hydrated alumina and additives are mixed and molded, dried, and then calcined in air for 2-6 hours to obtain a carrier. The carrier is immersed in the prepared aqueous solution containing cobalt and/or nickel compound, molybdenum and/or tungsten compound for 1-4 hours, dried, and calcined at 300-550° C. for 1-3 hours to obtain the catalyst product.

The aqueous solution of cobalt, molybdenum, nickel and tungsten compounds can be prepared by conventional methods. Cobalt, molybdenum, nickel and tungsten compounds are selected from one or more of their soluble compounds. Wherein the molybdenum compound is preferably ammonium molybdate, and the cobalt compound is preferably one or more of cobalt nitrate, cobalt chloride, and basic cobalt carbonate. The compounds of nickel and tungsten are preferably one or more of nickel nitrate, nickel chloride, basic nickel carbonate, ammonium tungstate, ammonium metatungstate, ethyl ammonium metatungstate, and nickel metatungstate.

The hydrated alumina is preferably pseudo-boehmite or pseudo-boehmite.

The waste residue oil hydrogenation catalyst in the second hydrogenation reactor is the residue oil hydrogenation catalyst used in the residue oil hydrogenation process. After the waste residue oil hydrogenation catalyst is loaded into the second hydrogenation reactor, no Regeneration does not require pre-sulfurization either.

Residue hydrogenation catalysts need to have a certain proportion of mesopores to macropores and high pore volume, so that the high-viscosity macromolecules in the residue can reach the active surface of the catalyst, and at the same time, they can accommodate a large amount of metals and coke. During the reaction process, due to the deposition of metal and coke on the catalyst, the active center of the catalyst is gradually covered and the pores are narrowed, resulting in the loss of the catalyst's reactivity. When the activity of the residual oil hydrogenation catalyst decreases to the point that the residual oil hydrogenation product cannot meet the requirements of the refinery, it will be unloaded. The deactivation of residual oil hydrogenation catalyst is mainly caused by metal deposition, which is irreversible, and the catalyst cannot be reused by regeneration. Therefore, the unloaded residual oil hydrogenation catalyst can only be disposed of normally.

However, since gasoline hydrodesulfurization is generally carried out under the condition of gas phase reaction, the narrowed catalyst pores can still meet the needs of gasoline hydrodesulfurization reaction. Moreover, the waste residue oil hydrogenation catalyst still has a certain hydrogenation activity. Compared with the fresh catalyst, the residual activity is about 10-40% of the fresh catalyst. Waste residue oil hydrogenation catalysts usually contain heavy metals Ni, V, Fe and coke, the pore volume and specific surface area of the catalyst are greatly reduced, and the metals deposited on the catalyst are all in the state of sulfide, such as V ₃ S ₄ , Ni ₃ S ₂ , etc. . The V ₃ S ₄ deposited on the catalyst not only changes the pore structure of the catalyst, but also has a certain hydrogenation catalytic activity. The inventors of the present invention have found through experiments that the waste residue hydrogenation catalyst can exhibit higher selectivity of desulfurization activity relative to olefin hydrogenation saturation activity when processing gasoline fractions. The reason for the analysis is that the hydrodesulfurization reaction and olefin hydrogenation saturation reaction in the gasoline process are carried out on two different active centers, and the carbon deposits on the waste residue hydrogenation catalyst cover more olefin hydrogenation active centers. The hydrogen desulfurization active centers are relatively more reserved, so the catalyst shows a higher desulfurization selectivity. In the method provided by the invention, the hydrogenation desulfurization activity of the waste residue oil hydrogenation catalyst is utilized in the second hydrogenation reactor, and its higher desulfurization selectivity due to deactivation due to carbon deposition is utilized. The pore volume of the waste residue oil hydrogenation catalyst is 0.1-0.5mL/g, and the specific surface area is 10-100m ² /g. Based on the waste residue oil hydrogenation catalyst, the metal deposited on the waste residue oil hydrogenation catalyst The total amount is 1-50% by weight, the deposited coke is 5-30% by weight, and the deposited metals include vanadium, nickel and/or iron.

The residue hydrogenation catalyst is a Group VIB non-noble metal catalyst and/or a Group VIII non-noble metal catalyst supported on an alumina carrier. The residue hydrogenation catalyst according to the present invention, wherein the Group VIB non-noble metal is preferably molybdenum, and the Group VIII non-noble metal is preferably cobalt, calculated as oxides and based on the total weight of the catalyst, containing 8.0% by weight to 30% by weight molybdenum, 1.0 wt% to 10.0 wt% cobalt.

Advantages of the present invention:

1. The present invention can process catalytic cracking gasoline with high olefin content in my country, and the total sulfur content of the obtained full-cut gasoline product is less than 10 μg/g, and compared with the raw material of full-cut gasoline, the loss of octane number is small, and the loss of RON is less than 1.5 units .

2. By using the stripping tower between the two reactors, the reaction feed entering the second reactor does not contain hydrogen sulfide, which is mixed with the recycled hydrogen after dehydrogen sulfide treatment for selective hydrodesulfurization again The resulting product is not easy to generate regenerated mercaptan sulfur, so it is easier to achieve the goal of a total sulfur content of less than 10 μg/g.

3. Using the waste residue oil hydrogenation catalyst in the second hydrogenation reactor can not only make use of its hydrodesulfurization activity and desulfurization selectivity for gasoline fractions, but also realize the secondary utilization of the residue oil hydrodesulfurization catalyst, saving enterprises cost and is environmentally friendly.

4. The total sulfur content and the mercaptan sulfur content of the outlet stream of the second hydrogenation reactor are both less than 10 μg/g, and no further oxidative sweetening process is required, which reduces the discharge of waste lye and makes the production process more environmentally friendly.

Description of drawings

The accompanying drawing is a schematic flow chart of the method for producing ultra-low sulfur gasoline provided by the present invention.

Detailed ways

The method provided by the present invention will be further described below in conjunction with the accompanying drawings.

The combined method for producing ultra-low-sulfur gasoline provided by the present invention is described in detail as follows: the whole fraction gasoline raw material from the pipeline 1 enters the fractionation tower 2, and after fractionation, light fraction gasoline and heavy fraction gasoline are obtained. The light gasoline fraction is drawn out through the pipeline 3 and sent to the alkali extraction unit 4 for alkali washing and refining to remove mercaptans, and the resulting refined light distillate gasoline is sent to the product tank through the pipeline 5. The heavy distillate gasoline is drawn from the pipeline 6, and after being boosted by the raw material pump 7, it is mixed with the hydrogen from the pipeline 34, then enters the heat exchanger 9 through the pipeline 8, exchanges heat with the material from the pipeline 23, and enters the heating furnace 11 through the pipeline 10 to raise the temperature , and then enter the first hydrogenation reactor 13 through the pipeline 12 for selective hydrodesulfurization reaction. The effluent of the first hydrogenation reactor 13 enters the intermediate stripper 15 through the pipeline 14, and removes impurities such as hydrogen sulfide in the liquid phase under the stripping action of fresh hydrogen from the pipeline 16, and the gas phase containing hydrogen sulfide flows through The pipeline 17 is sent to the circulating hydrogen dehydrogenation tower 31; the liquid-phase flow without hydrogen sulfide enters the heat exchanger 19 from the pipeline 18, and after exchanging heat with the effluent of the second hydrogenation reactor 21 from the pipeline 22, it is passed through Line 20 feeds a second hydrogenation reactor 21 . The effluent of the second hydrogenation reactor is sent out through the pipeline 22, and enters the high-pressure separator 25 through the pipeline 24 after heat exchange through the heat exchanger 19, the pipeline 23 and the heat exchanger 9 in turn. After the high-pressure separator 25 performs vapor-liquid separation, the hydrogen-rich gas flow at the top enters the circulating hydrogen dehydrogenation tower 31 through the pipeline 30, and the hydrogen from the top of the tower enters the circulating hydrogen compressor 33 through the pipeline 32, and is increased by the circulating hydrogen compressor. After pressure, one path is mixed with the material at the outlet of the raw material pump 7 through the pipeline 34, and one path is mixed with the stream from the pipeline 20 through the pipeline 35 to enter the second hydrogenation reactor 21. The stream obtained from the lower part of the high-pressure separator 25 enters the stabilizing tower 27 through the pipeline 26, the light hydrocarbon gas at the top of the tower is extracted through the pipeline 28, and the tower bottom product is sent to the product tank through the pipeline 29.

The following examples will further illustrate the method provided by the present invention, but do not limit the present invention thereby.

The trade name of the selective hydrodesulfurization catalyst used in Comparative Example 1 is RSDS-1, produced by Sinopec Catalyst Company.

The selective hydrodesulfurization catalyst used in the first hydrogenation reactor in Example 1 is catalyst C, and the waste residue hydrogenation catalyst used in the second hydrogenation reactor is the waste agent of the catalyst whose trade name is RMS-1. The residual oil hydrogenation catalyst with the brand name RMS-1 was produced by Sinopec Catalyst Company. The waste RMS-1 used has been operated for nearly 10,000 hours in a fixed-bed residual oil hydrogenation unit, and its main properties are listed in Table 1.

The carrier of catalyst C is alumina, and the active metal composition is: 13.0% by weight of molybdenum oxide and 3.8% by weight of cobalt oxide.

Comparative example 1

A kind of FCC gasoline F1 is used as raw material oil, and its properties are shown in Table 2. Taking 68°C as the cut point, the raw material oil F1 was cut into light fraction and heavy fraction, and the obtained light fraction and heavy fraction accounted for 35.0% by weight and 65.0% by weight of the raw material, respectively. The light fraction is desulfurized by alkali refining, and the heavy fraction is mixed with hydrogen and enters the fixed bed reactor to contact with catalyst RSDS-1 for selective hydrodesulfurization reaction. The light distillate after sweetening and the heavy distillate after hydrogenation are reconciled to obtain the whole distillate gasoline product. The hydrogenation process conditions and the properties of the full distillate gasoline products are listed in Table 3. It can be seen from Table 3 that even if the reaction temperature is as high as 330 °C, the sulfur content (25 μg/g) of the whole distillate product cannot be less than 10 μg/g, and the RON loss is as high as 7.5 units. And the mercaptan sulfur content of the whole distillate product is 16 μg/g, and it needs to be oxidative sweetening treatment to make it meet the gasoline factory requirements of mercaptan sulfur <10 μg/g, but the total sulfur of the product after oxidation sweetening still cannot Less than 10μg/g.

Example 1

Example 1 uses the same raw material oil F1 as in Comparative Example 1, and cuts the raw material oil F1 into light and heavy fractions at 68°C, and the obtained light fraction and heavy fraction account for 35.0% by weight and 65.0% by weight of the raw material respectively. %. The light fraction is refined by alkali washing to remove mercaptan sulfur. After the heavy fraction is mixed with hydrogen, it first enters the first hydrogenation reactor to contact with catalyst C for selective hydrodesulfurization, and then removes hydrogen sulfide through the intermediate stripping tower, and then mixes with hydrogen and enters the second hydrogenation reactor. Continue desulfurization under the action of waste RMS-1 to obtain refined heavy distillate gasoline. The refined light and heavy fractions are blended to produce a full-distillate gasoline product. The reaction conditions of the first hydrogenation reactor and the second hydrogenation reactor and the properties of the whole distillate products are shown in Table 3. It can be seen from Table 3 that the sulfur content of the whole distillate product is 6.8 μg/g, the sulfur content of mercaptans is less than 3 μg/g, the olefin content is 31.0% by volume, and the RON loss is only 1.4.

Comparative example 2

A kind of FCC gasoline F2 is used as raw material oil, and its properties are shown in Table 2. Taking 65°C as the cut point, the feed oil F2 was cut into light and heavy fractions, and the resulting light fraction and heavy fraction accounted for 33.0% by weight and 67.0% by weight of the raw material, respectively. The light fraction is desulfurized by alkali refining, and the heavy fraction is mixed with hydrogen and enters the fixed bed reactor to contact with catalyst C for selective hydrodesulfurization reaction. The light distillate after sweetening and the heavy distillate after hydrogenation are reconciled to obtain the whole distillate gasoline product. The hydrogenation process conditions and the properties of the whole distillate gasoline products are listed in Table 4. It can be seen from Table 4 that when the reaction temperature is 320°C, the sulfur content of the whole distillate product is 9.0 μg/g, the olefin content of the product is 18.0% by volume, and the RON loss is 3.0 units.

Example 2

A kind of FCC gasoline F2 is used as raw material oil, and its properties are shown in Table 2. Still taking 65°C as the cutting point to cut the feed oil F2 into light fraction and heavy fraction, the obtained light fraction and heavy fraction account for 33.0% by weight and 67.0% by weight of the raw material respectively. The light fraction is refined by alkali washing to remove mercaptan sulfur. After the heavy fraction is mixed with hydrogen, it first enters the first hydrogenation reactor to contact with catalyst C for selective hydrodesulfurization, and then removes hydrogen sulfide through the intermediate stripping tower, and then mixes with hydrogen and enters the second hydrogenation reactor. Continue desulfurization under the action of waste RMS-1 to obtain refined heavy distillate gasoline. The refined light and heavy fractions are blended to produce a full-distillate gasoline product. The reaction conditions of the first hydrogenation reactor and the second hydrogenation reactor and the properties of the whole cut product are shown in Table 4. It can be seen from Table 4 that the sulfur content of the whole distillate product can be reduced to 8.5 μg/g only by using the reaction temperatures of 295 °C and 290 °C in the first and second hydrogenation reactors respectively. At this time, the sulfur content of mercaptans is 3 μg/g, the olefin content is 24.5% by volume, and the RON loss is 1.1 units.

Example 3

A kind of FCC gasoline F3 is used as raw material oil, and its properties are shown in Table 2. Taking 60°C as the cut point, the feed oil F3 was cut into light and heavy fractions, and the obtained light fraction and heavy fraction accounted for 30.0% by weight and 70.0% by weight of the raw material, respectively. The light fraction is refined by alkali washing to remove mercaptan sulfur. After the heavy fraction is mixed with hydrogen, it first enters the first hydrogenation reactor to contact with catalyst C for selective hydrodesulfurization, and then removes hydrogen sulfide through the intermediate stripping tower, and then mixes with hydrogen and enters the second hydrogenation reactor. Continue desulfurization under the action of waste RMS-1 to obtain refined heavy distillate gasoline. The refined light and heavy fractions are blended to produce a full-distillate gasoline product. The reaction conditions of the first hydrogenation reactor and the second hydrogenation reactor and the properties of the whole cut product are shown in Table 5. It can be seen from Table 5 that the sulfur content of the whole distillate product is 3.8 μg/g, the sulfur content of mercaptans is less than 3 μg/g, the olefin content is 21.5% by volume, and the RON loss is only 0.8.

Table 1

Catalyst Waste RMS-1 Specific surface area, m ² /g 74 Pore volume, mL/g 0.15 Impurity content, weight % S 9.6 C 12.2 N 0.21 Ni+V 11.5 Ni+V+Fe+Ca+Na 13.1

Table 2

raw material name F1 F2 F3 Density (20℃), g/ ^cm3 0.7320 0.7300 0.7250 Sulfur content, μg/g 942 550 380 Olefin, volume % 38.8 30.0 25.0 Distillation range (ASTM D86), °C initial boiling point 28 32 33 10% 44 43 44 50% 94 89 85 90% 175 169 168 end point 198 191 193 RON 92.7 94.0 93.4

table 3

Table 4

table 5

Claims (10)

1. produce a combined method for super low-sulfur oil, comprising:

(1) gasoline stocks is fractionated into lighting end gasoline and last running gasoline, and wherein the cut point of lighting end gasoline and last running gasoline is 50 DEG C ~ 70 DEG C;

(2) lighting end gasoline enters alkali density unit, refines the mercaptan sulfur removed wherein through alkali cleaning, obtains refining lighting end gasoline;

(3) last running gasoline is together with hydrogen, enter the first hydrogenator to contact with catalyst for selectively hydrodesulfurizing and react, the reaction effluent of the first hydrogenator enters middle gas stripping column and carries out air lift, middle gas stripping column gained liquid phase stream enters the second hydrogenator together with hydrogen, contact with waste residue oil hydrogenation catalyst and react, the temperature of reaction of the second hydrogenator is lower than the temperature of reaction of the first hydrogenator, with waste residue oil hydrogenation catalyst for benchmark, the total metal content that described waste residue oil hydrogenation catalyst deposits is 1 ~ 50 heavy %, the coke of deposition is 5 ~ 30 heavy %,

The reaction effluent of (4) second hydrogenators carries out cooling, being separated, and isolated liquid phase stream enters stabilizer tower, and stable bottom stream is hydrogenation last running gasoline,

(5) the refining lighting end gasoline of step (2) gained mixes with the hydrogenation last running gasoline of step (4) gained, obtains super low-sulfur oil cut.

2. in accordance with the method for claim 1, it is characterized in that, the reaction conditions of the first hydrogenator and the second hydrogenator is: hydrogen dividing potential drop 1.0 ~ 4.0MPa, temperature of reaction 200 ~ 400 DEG C, volume space velocity 2 ~ 8h ^-1, hydrogen to oil volume ratio 200 ~ 1000Nm ³/ m ³.

3. in accordance with the method for claim 1, it is characterized in that, the stripping medium of middle gas stripping column is hydrogen, and the operational condition of middle gas stripping column is: pressure 1.0 ~ 4.0MPa.

4. in accordance with the method for claim 1, it is characterized in that, the temperature of reaction of the second hydrogenator is lower than the temperature of reaction of the first hydrogenator 5 ~ 50 DEG C.

5. according to the method described in claim 1 or 4, it is characterized in that, catalyst for selectively hydrodesulfurizing is the group vib base metal of a kind of load on aluminum oxide and/or silica-alumina supports and/or group VIII non-precious metal catalyst.

6. according to the method described in claim 1 or 4, it is characterized in that, in described selective desulfurization catalyst, group vib base metal is selected from molybdenum and/or tungsten, group VIII base metal is selected from cobalt and/or nickel, be benchmark with oxide basis and with total catalyst weight, this catalyst for selectively hydrodesulfurizing contains molybdenum and/or the tungsten of the 5.0 heavy % in heavy % ~ 20, the nickel of the 2.0 heavy % in heavy % ~ 10.0 and/or cobalt.

7. in accordance with the method for claim 1, it is characterized in that, described waste residue oil hydrogenation catalyst is the residual oil hydrocatalyst after coming from the use of residual hydrogenation process, after waste residue oil hydrogenation catalyst is packed into the second hydrogenator, does not need regeneration also need not carry out prevulcanized.

8. according to the method described in claim 1 or 7, it is characterized in that, the pore volume of waste residue oil hydrogenation catalyst catalyzer is 0.1 ~ 0.5mL/g, and specific surface area is 10 ~ 100m ²/ g.

9. in accordance with the method for claim 7, it is characterized in that, described residual oil hydrocatalyst be load group vib base metal on the alumina support and/or group VIII non-precious metal catalyst, wherein group vib base metal is preferably molybdenum, group VIII base metal is preferably cobalt, be benchmark with oxide basis and with total catalyst weight, the molybdenum containing the 8.0 heavy % in heavy % ~ 30, the cobalt of the 1.0 heavy % in heavy % ~ 10.0.

10. in accordance with the method for claim 1, described gasoline stocks is selected from one or more in catalytically cracked gasoline, catalytic cracking gasoline, straight-run spirit, coker gasoline, pyrolysis gasoline and pressure gasoline, final boiling point ≯ 220 DEG C of above-mentioned gasoline.