Method for producing low-sulfur residue type ship fuel

Abstract

The invention relates to a method for producing low-sulfur residue type ship fuel, which comprises the following steps: carrying out selective hydrodesulfurization on distillate oil with the hydrogen mass fraction of not greater than 10.5% to obtain hydrogenated oil with the sulfur mass fraction of not greater than 0.1%, and blending the hydrogenated oil with heavy oil with the sulfur mass fraction of not greater than 1.0% to obtain the low-sulfur residue type ship fuel. On one hand, the low-cost blending component is preferably selected, and on the other hand, the selective hydrodesulfurization of the distillate oil is controlled under the low-pressure and high-temperature operation conditions, so that the hydrodesulfurization selectivity is improved, the hydrogen consumption is reduced, and the cost for producing the low-sulfur residue type ship fuel is integrally reduced.

Description

Technical Field

[0001] The invention relates to the field of hydrocarbon oil raw material processing, and in particular to a method for producing low-sulfur residual marine fuel. Background Art

[0002] As global environmental problems continue to intensify, environmental regulations have been introduced at home and abroad to limit the sulfur content of marine fuel oil (hereinafter referred to as marine fuel). The International Maritime Organization (IMO) requires that the sulfur content of fuel oil used by ships sailing in ordinary areas must be ≤0.5% by mass from January 1, 2020. In addition to the sulfur content requirement of ≤0.5% by mass, many other indicators of low-sulfur residual marine fuel are relatively loose (for details, please refer to GB17411-2015 or ISO8217), such as RMG400 residual carbon value ≤18% by mass, and vanadium ≤350μg / g.

[0003] Therefore, in the process of producing low-sulfur residual marine fuel, how to optimize the process conditions and catalysts according to product requirements, improve the selectivity of hydrodesulfurization, and thus reduce hydrogen consumption and costs to a certain extent, is a problem that needs to be solved at present.

[0004] CN112300833A discloses a method for producing low-sulfur residual marine fuel, which comprises sequentially loading a hydroprotection catalyst, a hydrodemetallization catalyst and a hydrodemetallization desulfurization catalyst in a residual oil hydrotreating device along the logistics direction. The method improves the catalyst grading to produce low-sulfur residual marine fuel at low cost and in a long period.

[0005] CN114471633A discloses a hydrodesulfurization catalyst, a preparation method and application thereof, and a method for producing marine fuel. The catalyst comprises a carrier and an active component loaded on the carrier. The expression of the active component is Fe x Ni y P, x is 0-1.5, y is 0.5-2, and x+y is not greater than 2; the carrier is alumina, and the Al2O3 has a bimodal structure. The present invention adopts an alumina carrier with a bimodal structure to prepare a hydrodesulfurization catalyst, the catalyst has a higher desulfurization rate and lower hydrogen consumption, and the catalyst is particularly suitable for the process of preparing marine fuel by hydrodesulfurization reaction of residual oil, and the hydrogen consumption is lower under the premise of better desulfurization effect of residual oil. Summary of the invention

[0006] The invention aims to solve the problem of how to reduce the cost of producing low-sulfur residual marine fuel.

[0007] After a large number of experiments and systematic thinking, the inventors of the present invention concluded that the difficulty in blending low-sulfur residual marine fuel at low cost lies in meeting the requirements of viscosity and sulfur content at the same time; the blending components of low-sulfur residual marine fuel usually include at least a low-viscosity light component and a high-viscosity heavy component. How to effectively coordinate the sulfur content in different components so that the oil obtained after blending meets the sulfur content requirement of marine fuel; further, how to design the hydrogenation path according to the sulfur content requirement of the required components to effectively reduce hydrogen consumption are all difficult problems.

[0008] The reactions involved in the oil hydrofining process mainly include hydrodesulfurization, hydrodenitrogenation and aromatic saturation, etc., and there are usually different reaction paths in the hydrogenation reaction, which will lead to obvious differences in the hydrogen consumption of different hydrogenation reactions or different reaction paths of the same hydrogenation reaction. For example, the hydrodesulfurization reaction includes a direct desulfurization path and a hydrogenation-first-desulfurization path, in which the former does not need to go through aromatic saturation to directly remove sulfur atoms, while the latter needs to first saturate the aromatic ring next to the sulfur atom and then remove the sulfur atom, so the hydrogen consumption of the former is lower than that of the latter. After a large number of experiments and systematic thinking, the inventors of the present invention have found that within the conventional operating conditions of distillate oil, when the hydrodesulfurization rate is usually increased, the degree of aromatic saturation will also increase, resulting in an increase in hydrogen consumption in the hydrodesulfurization process. However, when the distillate oil hydrogenation process is not within the conventional operating conditions, the hydrogen consumption of the distillate oil hydrodesulfurization process will be reduced when the reaction is adjusted in the aromatic saturation thermodynamic equilibrium control area. When operating in this region, the aromatic saturation rate is controlled by thermodynamic equilibrium and will decrease with increasing reaction temperature, but the hydrodesulfurization rate will increase with increasing reaction temperature. Therefore, the purpose of improving the hydrodesulfurization rate selectivity and reducing the hydrogen consumption in the hydrodesulfurization process can be achieved.

[0009] In order to achieve the above object, the present invention provides a method for producing low-sulfur residual marine fuel, comprising:

[0010] (1) After the distillate oil with a hydrogen mass fraction of ≯10.5% is mixed with hydrogen, it enters a fixed bed selective hydrodesulfurization reaction zone to contact and react with a hydrotreating catalyst, and the reaction effluent enters a gas-liquid separation zone for gas-liquid separation to obtain hydrogenated oil. The reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure 0.1-5.9 MPa, reaction temperature 390-460°C, hydrogen-to-oil volume ratio 800-2500, and volume space velocity 0.1-4.0 h -1 , the sulfur mass fraction of the obtained hydrogenated oil is ≯0.1% and the hydrogen mass fraction of the hydrogenated oil is ≯11.1%;

[0011] (2) The hydrogenated oil obtained in step (1) is blended with heavy oil having a sulfur mass fraction of ≯1.0% and a hydrogen mass fraction of ≯11.8% to obtain low-sulfur residual marine fuel, wherein the sulfur mass fraction of the low-sulfur residual marine fuel is ≯0.5% and the hydrogen mass fraction is ≯11.2%.

[0012] In the present invention, the initial distillation point of the distillate oil is in the range of 160-350°C, and the final distillation point is in the range of 300-560°C.

[0013] In one embodiment of the present invention, the distillate oil is selected from one or more of catalytic diesel, catalytic slurry oil, coal tar, coker diesel, and coker wax oil.

[0014] In the present invention, the initial boiling point of the heavy oil is in the range of 350-560° C. Preferably, the heavy oil is selected from one or more of hydrogenated slag and straight distillation slag.

[0015] In one embodiment of the present invention, the reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure 1.0-5.0 MPa, reaction temperature 400-450°C, hydrogen-oil volume ratio 1000-2000, volume space velocity 0.2-3.0 h -1 .

[0016] The present invention controls the reaction stage of the distillate oil to react in the low-pressure and high-temperature aromatic saturation thermodynamic equilibrium control zone, thereby improving the selectivity of the direct desulfurization reaction path. Under preferred circumstances, the sulfur mass fraction of the obtained hydrogenated oil is ≯0.1% and the hydrogen mass fraction of the hydrogenated oil is ≯11.0%.

[0017] Since the aromatic saturation thermodynamic equilibrium control zone has the characteristics of low pressure and high temperature, the activity stability of the catalyst is affected to a certain extent when operating in the aromatic saturation thermodynamic equilibrium control zone. In order to ensure the stability of the hydroprocessing catalyst, in a preferred case, in step (1), it also includes an online cleaning carbon deposition stage: the distillate oil, the circulating oil and the hydrogen are mixed together and enter the fixed bed selective hydrodesulfurization reaction zone to contact the hydroprocessing catalyst, the reaction effluent enters the gas-liquid separation zone for gas-liquid separation, and at least part of the liquid phase is returned to the raw material buffer tank as the circulating oil. The reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure of 6.0-12.0MPa, reaction temperature of 350-460℃, hydrogen-to-oil volume ratio of 200-2500, volume space velocity of 0.1-4.0h -1 .

[0018] The present invention preferably adopts an online carbon deposit cleaning method, which can partially eliminate catalyst carbon deposits formed during low-pressure and high-temperature operation and slow down the deactivation rate of the hydroprocessing catalyst.

[0019] In one embodiment of the present invention, the duration of the online cleaning of carbon deposits is 1-10 days.

[0020] In one embodiment of the present invention, when the hydrodesulfurization rate of the hydrogenated oil is less than 90%, the online cleaning of carbon deposits is started; or, the online cleaning of carbon deposits is started once every 1-6 months.

[0021] There is no particular limitation on the type and number of fixed bed reactors used in the selective hydrodesulfurization reaction zone. Preferably, the fixed bed reactors can be selected from one or more of an upflow reactor and a downflow reactor.

[0022] In one embodiment of the present invention, the hydroprocessing catalyst comprises one or more catalysts, each of which independently contains a carrier and 0-35 mass % of an active metal component, wherein the active metal component is selected from at least one of Group VIB and / or Group VIIII non-noble metal elements.

[0023] Preferably, the active metal component is selected from at least one of a nickel-tungsten combination, a nickel-tungsten-cobalt combination, a nickel-molybdenum combination and a cobalt-molybdenum combination.

[0024] More preferably, in each of the hydroprocessing catalysts, the content of the active metal component calculated as metal oxide is 0.05-30% by mass.

[0025] Preferably, in each of the hydroprocessing catalysts, the carrier is independently selected from at least one of alumina, silica and titania.

[0026] Preferably, each of the hydroprocessing catalysts independently further contains at least one promoter element selected from boron, germanium, zirconium, phosphorus, chlorine and fluorine.

[0027] Preferably, in each of the hydroprocessing catalysts, the total content of the promoter elements, calculated as elements, is 0-10% by mass.

[0028] In one embodiment of the present invention, the average particle size of each of the hydroprocessing catalysts is independently 0.5-50 mm, and the bulk density of each of the hydroprocessing catalysts is independently 0.3-1.2 g / cm 3 The average pore size of each of the hydroprocessing catalysts is independently 6-30 nm, and the specific surface area of ​​each of the hydroprocessing catalysts is independently 50-400 m 2 / g.

[0029] In a preferred embodiment, the average pore volume of each of the hydroprocessing catalysts is independently 0.1-5 mL / g.

[0030] The gas-liquid separation zone is well known to those skilled in the art and may include a hot high fractionator, a cold high fractionator, a hot low fractionator, a cold low fractionator, a stripping tower and a distillation tower, etc., and its operating conditions are also well known to those skilled in the art.

[0031] Unless otherwise specified, the reaction pressure in the present invention is expressed in the form of hydrogen partial pressure.

[0032] Unless otherwise specified, the pressures described in the present invention are gauge pressures.

[0033] Preferably, in the step (2), there is no particular restriction on the blending ratio of the hydrogenated oil and the heavy oil, as long as the sulfur mass fraction after blending is ≯0.5% and the hydrogen mass fraction is ≯11.2%, and other indicators meet the requirements of low-sulfur residual marine fuel (such as RMG-380 or RMG-180, etc., for specific indicators, refer to GB17411-2015 or ISO8217).

[0034] Features of the present invention: On the one hand, the present invention preferably selects low-cost blending raw materials, and on the other hand, controls the distillate oil hydrogenation to react in the low-pressure and high-temperature aromatic saturation thermodynamic equilibrium control area, thereby improving the hydrodesulfurization selectivity and reducing hydrogen consumption. At the same time, it is preferred to increase the online cleaning carbon deposition process, thereby overcoming the problem of poor activity stability of the hydroprocessing catalyst caused by carbon deposition. The present invention can significantly reduce the cost of the low-sulfur residual marine fuel production process and improve its economic efficiency. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the examples, but the present invention is not limited thereto. In the following examples, unless otherwise specified, all raw materials used can be obtained from commercial channels.

[0036] The reactions in the following examples were carried out in a fixed bed hydroprocessing unit.

[0037] The raw materials used in the following examples and their properties are shown in Table 1, wherein catalytic diesel is distillate oil, and hydrogenated residue and low-sulfur residue are heavy oils.

[0038] The hydroprocessing catalyst used in the following examples was produced by the Changling Catalyst Plant of Sinopec Catalyst Branch Company, and its physicochemical properties are shown in Table 2.

[0039] Table 1

[0040] raw material Catalytic diesel Hydrogenation and slag reduction Low sulfur slag <![CDATA[Density (20 °C), g / cm 3 > 0.9328 0.9670 1.006 <![CDATA[Viscosity at 50°C, mm 2 / s]]> - 5800 32000 Sulfur content, mass% 0.645 0.80 0.80 Nitrogen content, μg / g 521 0.42 0.60 Hydrogen content, mass% 9.90 11.66 11.20 Paraffins, mass% 14.0 - - Cycloalkanes, mass % 6.5 - - Total aromatics, mass% 74.5 - - Initial distillation point, ℃ 203 540 540 Final distillation point, ℃ 339 - -

[0041] Table 2

[0042] catalyst A <![CDATA[MO3, mass %]]> 15.0 CoO, mass% 4.0 Average pore volume, mL / g 0.50 <![CDATA[Specific surface area, m 2 / g]]> 175 <![CDATA[Bulk density, g / cm 3 > 0.65 Average particle size, mm 1.1

[0043] Example 1

[0044] Catalytic diesel was hydrotreated in the selective hydrodesulfurization reaction zone. The hydrotreatment catalyst used was A. The process conditions were shown in Table 3. After 10 days of operation, the sulfur content of the hydrogenated oil was 24μg / g and the hydrogen mass fraction was 10.31% by mass. After that, carbon cleaning was performed each time the desulfurization rate dropped to 90%. Each cleaning lasted for 5 days. During the cleaning period, the weight ratio of circulating oil to fresh oil was 1:1, the hydrogen partial pressure was 8.0MPa, the reaction temperature was 380℃, and the other process conditions remained unchanged. After each cleaning, the original conditions were restored and the operation was continued. After one year of operation (excluding the carbon cleaning time), the sulfur content of the hydrogenated oil was 286μg / g and the hydrogen mass fraction was 10.38% by mass. The specific results are listed in Table 3.

[0045] Comparative Example 1

[0046] The catalytic diesel was hydrotreated in the selective hydrodesulfurization reaction zone, and the hydrotreatment catalyst used was A. The process conditions were shown in Table 3. After 10 days of operation, the sulfur content of the hydrogenated oil was 24 μg / g, and the hydrogen mass fraction was 10.31% by mass. After continuing to operate for 4 months, the sulfur content of the hydrogenated oil was 735 μg / g, and the hydrogen mass fraction was 10.39% by mass. The specific results are listed in Table 3. Compared with Example 1, it can be seen that the carbon cleaning during operation can significantly extend the operation cycle.

[0047] Comparative Example 2

[0048] Raw material A was subjected to conventional hydrotreatment, the hydrotreatment catalyst used was A, and the process conditions were as shown in Table 3. After 10 days of operation, the sulfur content of the hydrotreated oil was 25 μg / g, and the hydrogen mass fraction was 11.10% by mass. The specific results are listed in Table 3. Compared with Example 1, it can be seen that when the sulfur content of the hydrotreated oil is equivalent, the present invention can significantly reduce the hydrogen consumption in the hydrodesulfurization process.

[0049] Table 3

[0050]

[0051]

[0052] Example 2

[0053] In this embodiment, the hydrogenation oil produced when the embodiment 1 was operated for 10 days was blended with the hydrogenation residue at a mass ratio of 45:55 to obtain the properties of the low-sulfur marine fuel as shown in Table 4. As can be seen from Table 4, the viscosity of the blended low-sulfur marine fuel meets the requirements of RMG180, and the sulfur mass fraction is 0.44%, and the hydrogen mass fraction is 11.05%.

[0054] Example 3

[0055] In this embodiment, the hydrogenation oil produced when the embodiment 1 was operated for 10 days was blended with the low-sulfur reduced slag at a mass ratio of 54:46, and the properties of the low-sulfur marine fuel were shown in Table 4. As can be seen from Table 4, the viscosity of the blended low-sulfur marine fuel meets the requirements of RMG180, and the sulfur mass fraction is 0.37%, and the hydrogen mass fraction is 10.72%.

[0056] Comparative Example 3

[0057] In this embodiment, the hydrogenation oil produced when the comparative example 2 was operated for 10 days was blended with the hydrogenation residue at a mass ratio of 45:55 to obtain the properties of the low-sulfur marine fuel as shown in Table 4. As can be seen from Table 4, the viscosity of the blended marine fuel meets the requirements of RMG180, the sulfur mass fraction is 0.44%, and the hydrogen mass fraction is 11.41%.

[0058] It can be seen that the present invention, such as Example 2 and Example 3, can obtain low-sulfur marine fuel with a lower hydrogen mass fraction, which can significantly reduce the production cost of marine fuel.

[0059] Table 4

[0060] Low sulfur marine fuel properties Example 2 Example 3 Comparative Example 3 <![CDATA[Density (20 °C), g / cm 3 > 0.9467 0.9606 0.9368 <![CDATA[Viscosity at 50°C, mm 2 / s]]> 89 91 87 Sulfur mass fraction, mass% 0.44 0.37 0.44 Hydrogen mass fraction, mass% 11.05 10.72 11.41

[0061] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for producing low-sulfur residual marine fuel, include: (1) After the distillate oil with a hydrogen mass fraction of ≯10.5% is mixed with hydrogen, it enters a fixed bed selective hydrodesulfurization reaction zone to contact and react with a hydrotreating catalyst, and the reaction effluent enters a gas-liquid separation zone for gas-liquid separation to obtain hydrogenated oil. The reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure 0.1-5.9 MPa, reaction temperature 390-460°C, hydrogen-to-oil volume ratio 800-2500, and volume space velocity 0.1-4.0 h -1 , the sulfur mass fraction of the obtained hydrogenated oil is ≯0.1% and the hydrogen mass fraction of the hydrogenated oil is ≯11.1%; (2) The hydrogenated oil obtained in step (1) is blended with heavy oil having a sulfur mass fraction of ≯1.0% and a hydrogen mass fraction of ≯11.8% to obtain low-sulfur residual marine fuel, wherein the sulfur mass fraction of the low-sulfur residual marine fuel is ≯0.5% and the hydrogen mass fraction is ≯11.2%.

2. The method according to claim 1, It is characterized in that The reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure 1.0-5.0MPa, reaction temperature 400-450℃, hydrogen-oil volume ratio 1000-2000, volume space velocity 0.2-3.0h -1 .

3. The method according to claim 1, It is characterized in that The sulfur mass fraction of the obtained hydrogenated oil is ≯0.1% and the hydrogen mass fraction of the hydrogenated oil is ≯11.0%.

4. The method according to claim 1, It is characterized in that In step (1), an online carbon cleaning stage is also included: the distillate oil, the circulating oil and the hydrogen are mixed together and then enter the fixed bed selective hydrodesulfurization reaction zone to contact with the hydrotreating catalyst, the reaction effluent enters the gas-liquid separation zone for gas-liquid separation, and at least part of the liquid phase is returned to the raw material buffer tank as the circulating oil. The reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure of 6.0-12.0 MPa, reaction temperature of 350-460°C, hydrogen-to-oil volume ratio of 200-2500, and volume space velocity of 0.1-4.0 h -1 .

5. The method according to claim 4, It is characterized in that The duration of the online cleaning carbon deposition stage is 1-10 days.

6. The method according to claim 4, It is characterized in that When the hydrodesulfurization rate of the hydrogenated oil is less than 90%, start the online cleaning of carbon deposits; or, start the online cleaning of carbon deposits once every 1-6 months.

7. The method according to claim 1, It is characterized in that The initial boiling point of the distillate oil is within the range of 160-350°C, and the final boiling point is within the range of 300-560°C.

8. The method according to claim 7, It is characterized in that The distillate oil is selected from one or more of catalytic diesel, catalytic slurry oil, coal tar, coker diesel, and coker wax oil.

9. The method according to claim 1, It is characterized in that The initial boiling point of heavy oil is in the range of 350-560℃. Preferably, the heavy oil is selected from one or more of hydrogenated slag and straight distillation slag.

10. The method according to claim 1, It is characterized in that The hydroprocessing catalyst comprises one or more, and each of them independently contains a carrier and 0-35 mass % of an active metal component, wherein the active metal component is selected from at least one of the non-precious metal elements of Group VIB and / or Group VIIII; Preferably, the active metal component is selected from at least one of a nickel-tungsten combination, a nickel-tungsten-cobalt combination, a nickel-molybdenum combination and a cobalt-molybdenum combination; Preferably, in each of the hydroprocessing catalysts, the content of the active metal component calculated as metal oxide is 0.05-30 mass %; Preferably, in each of the hydroprocessing catalysts, the carrier is independently selected from at least one of alumina, silica and titania.

11. The method according to claim 10, It is characterized in that The average particle size of each of the hydroprocessing catalysts is independently 0.5-50 mm, and the bulk density of each of the hydroprocessing catalysts is independently 0.3-1.2 g / cm 3 The average pore size of each of the hydroprocessing catalysts is independently 6-30 nm, and the specific surface area of ​​each of the hydroprocessing catalysts is independently 50-400 m 2 / g.

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