A process for the production of low sulphur residual marine fuel

Abstract

The application relates to a method for producing low-sulfur residual marine fuel, which comprises selectively hydrodesulfurizing distillate oil with a hydrogen mass fraction of >10.5% to obtain hydrogenated oil with a sulfur mass fraction of >0.1%, blending the hydrogenated oil with heavy oil with a sulfur mass fraction of >1.0% to obtain low-sulfur residual marine fuel. The method can preferably use low-cost blending components, selectively hydrodesulfurize the distillate oil under low-pressure high-temperature operation conditions, improve the hydrodesulfurization selectivity, reduce hydrogen consumption, and thus reduce the overall cost of producing low-sulfur residual marine fuel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrocarbon oil feedstock processing, in particular to a method for producing low-sulfur residual type marine fuel. BACKGROUND

[0002] With the increasing global environmental problems, environmental protection 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 (English: International Maritime Organization, IMO for short) requires that the sulfur content of fuel oil used by ships sailing in general areas be ≯0.5 mass% from January 1, 2020. In addition to the requirement that the sulfur content of low-sulfur residual marine fuel be ≯0.5 mass%, many other indicators are relatively relaxed (for details, refer to GB17411-2015 or ISO8217), such as the RMG400 residual carbon value ≯18 mass%, and vanadium ≯350 μg / g.

[0003] Therefore, in the production of low-sulfur residual marine fuel, how to optimize the process conditions and catalysts according to the product requirements, improve the selectivity of hydrodesulfurization, and thus reduce hydrogen consumption and cost to some 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 filling a hydrogen protection catalyst, a hydrodemetallization catalyst and a hydrodemetallization and desulfurization catalyst in the flow direction in a residual oil hydroprocessing device. This method improves the catalyst gradation to produce low-sulfur residual marine fuel at low cost and for a long period.

[0005] CN114471633A discloses a hydrodesulfurization catalyst, a preparation method and application thereof, and a production method of marine fuel. The catalyst comprises a carrier and an active component supported on the carrier, and 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 hydrodesulfurization catalyst is prepared by using an alumina carrier with a bimodal structure. The catalyst has a higher desulfurization rate and lower hydrogen consumption, and is particularly suitable for the process of preparing marine fuel by residual oil hydrodesulfurization reaction. Under the premise of better residual oil desulfurization effect, the hydrogen consumption is lower. SUMMARY

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

[0007] The inventors of the present application find through a large number of experiments and systematic thinking that the difficulty of 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 one light component with low viscosity and one heavy component with high viscosity, how to effectively coordinate the sulfur content in different components so that the blended oil meets the sulfur content requirement of marine fuel; further, how to design the hydrogenation path according to the sulfur content requirement of the required component so as to effectively reduce hydrogen consumption are all difficult problems.

[0008] The reactions involved in the oil hydrogenation process mainly include hydrodesulfurization, hydrodenitrogenation and aromatic saturation, and different reaction paths exist in the hydrogenation reaction, which will result in obvious difference in hydrogen consumption of different hydrogenation reactions or different reaction paths of the same hydrogenation reaction. For example, the hydrodesulfurization reaction includes direct desulfurization path and hydrogenation-then-desulfurization path, wherein the former does not need to pass through aromatic saturation and directly removes sulfur atom, and the latter needs to saturate the aromatic ring beside the sulfur atom and then remove the sulfur atom, so the hydrogen consumption of the former is lower than that of the latter. The inventors of the present application find through a large number of experiments and systematic thinking that within the range of conventional operating conditions of distillate oil, the aromatic saturation degree will increase when the hydrodesulfurization rate increases, resulting in increase of hydrogen consumption in the hydrodesulfurization process. However, when the distillate oil hydrogenation process is not within the range of conventional operating conditions, adjustment in the aromatic saturation thermodynamic equilibrium control area will reduce the hydrogen consumption in the distillate oil hydrodesulfurization process. When operating in this area, the aromatic saturation rate is controlled by thermodynamic equilibrium, and the aromatic saturation rate will decrease with the increase of reaction temperature, but the hydrodesulfurization rate will increase with the increase of reaction temperature, so the purpose of improving the selectivity of hydrodesulfurization rate and reducing the hydrogen consumption in the hydrodesulfurization process can be achieved.

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

[0010] (1) mixing distillate oil with hydrogen mass fraction ≯10.5% with hydrogen to enter the fixed bed selective hydrodesulfurization reaction zone to react with the hydroprocessing catalyst, and the reaction effluent enters the gas-liquid separation zone to carry out gas-liquid separation to obtain hydrogenation product oil, and the reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure 0.1-5.9 MPa, reaction temperature 390-460 ℃, hydrogen to oil volume ratio 800-2500, and volume space velocity 0.1-4.0 h-1; -1 , the sulfur mass fraction of the obtained hydrogenation product oil is ≯0.1%, and the hydrogen mass fraction of the hydrogenation product oil is ≯11.1%;

[0011] (2) blending the hydrogenation product oil obtained in step (1) with heavy oil with sulfur mass fraction ≯1.0% and hydrogen mass fraction ≯11.8% to obtain low-sulfur residual marine fuel, and 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 application, the initial boiling point of the distillate oil is in the range of 160-350℃, and the final boiling point is in the range of 300-560℃.

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

[0014] In the present application, the initial boiling point of the heavy oil is in the range of 350-560℃. Preferably, the heavy oil is selected from one or more of hydro-reduced residue, straight-run residue.

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

[0016] The present application controls the reaction stage of the distillate oil in the low-pressure high-temperature aromatic saturation thermodynamic equilibrium control zone to carry out the reaction, improves the selectivity of the direct desulfurization reaction path, and in the preferred case, the sulfur mass fraction of the obtained hydrogenated product oil is ≯0.1% and the hydrogen mass fraction of the hydrogenated product oil is ≯11.0%.

[0017] Due to the low-pressure high-temperature characteristics of the aromatic saturation thermodynamic equilibrium control zone, 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 the preferred case, in step (1), an on-line cleaning of coke stage is further included: the distillate oil, the circulating oil and hydrogen are mixed together and then enter the fixed-bed selective hydrodesulfurization reaction zone to contact with the hydroprocessing catalyst, the reaction effluent enters the gas-liquid separation zone for gas-liquid separation, and at least part of the liquid phase returns to the raw material buffer tank as the circulating oil, the reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure 6.0-12.0 MPa, reaction temperature 350-460℃, hydrogen to oil volume ratio 200-2500, volume space velocity 0.1-4.0 h -1 .

[0018] The present application preferably adopts the method of on-line cleaning of coke, which can partially eliminate the catalyst coke formed during low-pressure high-temperature operation and delay the deactivation rate of the hydroprocessing catalyst.

[0019] In one embodiment of the present application, the duration of the on-line cleaning of coke stage is 1-10 days.

[0020] In one embodiment of the present application, when the hydrogen desulfurization rate of the hydrogenated product oil is <90%, the on-line cleaning of coke is started; or, the on-line cleaning of coke is started once every 1-6 months.

[0021] The fixed bed reactor type and number used in the selective hydrodesulfurization reaction zone are not particularly limited, and preferably can be selected from one or more of an upflow reactor and a downflow reactor.

[0022] In one embodiment of the present application, the hydrotreating catalyst comprises one or more, and each independently contains a support and 0-35 mass% of an active metal component selected from at least one of a Group VIB and / or a non-noble metal element of Group VIII.

[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, the content of the active metal component in each of the hydrotreating catalysts is 0.05-30 mass% in terms of metal oxide.

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

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

[0027] Preferably, the total content of the auxiliary elements in each of the hydrotreating catalysts is 0-10 mass% in terms of elements.

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

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

[0030] The gas-liquid separation zone is well known to those skilled in the art and can include a hot high separator, a cold high separator, a hot low separator, a cold low separator, a stripper column and a fractionating column, etc., and the operating conditions thereof are also well known to those skilled in the art.

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

[0032] The pressure described in the present application is all the gauge pressure, unless otherwise specified.

[0033] Preferably, in the step (2), the blending ratio of the hydrogenerated oil and the heavy oil is not particularly limited, as long as the sulfur mass fraction of the blending is ≯0.5% and the hydrogen mass fraction is ≯11.2% after blending, and other indexes meet the requirements of low-sulfur residual marine fuel (such as RMG-380 or RMG-180, etc., and the specific indexes can refer to GB17411-2015 or ISO8217).

[0034] The present application has the following characteristics: on one hand, the present application uses low-cost blending raw materials, and on the other hand, the distillate oil hydrogenation is controlled in the aromatic hydrocarbon saturation thermodynamic equilibrium control zone at low pressure and high temperature to improve the hydrogenation desulfurization selectivity and reduce hydrogen consumption, and meanwhile, the online cleaning of carbon deposition process is preferred, which overcomes the problem of poor activity stability of the hydrogenation treatment catalyst caused by carbon deposition. The present application can significantly reduce the cost of low-sulfur residual marine fuel production process and improve its economy. DETAILED DESCRIPTION

[0035] The present application will be further described in conjunction with the following examples, but the present application should not be limited in any way by the following examples. In the following examples, various raw materials used are all available from commercial channels, unless otherwise specified.

[0036] The reactions in the following examples are carried out in a fixed bed hydrogenation treatment device.

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

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

[0039] Table 1

[0040] Feedstock Catalytic diesel Hydrogenated foots Low sulfur foots Density (20°C), g / cm 3 ]] 0.9328 0.9670 1.006 50 °C viscosity, mm 2 / s]] - 5800 32000 Sulfur content, mass % 0.645 0.80 0.80 Nitrogen content, pg / g 521 0.42 0.60 Hydrogen content, mass % 9.90 11.66 11.20 Paraffins, mass % 14.0 - - Naphthenes, mass % 6.5 - - Total aromatics, mass % 74.5 - - Initial boiling point, °C 203 540 540 Final boiling point, °C 339 - -

[0041] Table 2

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

[0043] Example 1

[0044] The catalytic diesel is hydrotreated in the selective hydrodesulfurization reaction zone using the hydrotreating catalyst A, and the process conditions are shown in Table 3. After running for 10 days, the sulfur content of the hydrotreated oil is 24 μg / g, and the hydrogen mass fraction is 10.31 mass%. After that, the desulfurization rate is reduced to 90% each time, and a carbon deposit cleaning is performed each time. The weight ratio of the circulating oil to the fresh oil is 1:1 during the cleaning, the hydrogen partial pressure is 8.0 MPa, the reaction temperature is 380°C, and the other process conditions remain unchanged. After each cleaning, the original conditions are restored for continued running. After continued running for 1 year (not including the carbon deposit cleaning time), the sulfur content of the hydrotreated oil is 286 μg / g, and the hydrogen mass fraction is 10.38 mass%. The specific results are shown in Table 3.

[0045] Comparative Example 1

[0046] The catalytic diesel is hydrotreated in the selective hydrodesulfurization reaction zone using the hydrotreating catalyst A, and the process conditions are shown in Table 3. After running for 10 days, the sulfur content of the hydrotreated oil is 24 μg / g, and the hydrogen mass fraction is 10.31 mass%. After that, the desulfurization rate is reduced to 90% each time, and a carbon deposit cleaning is performed each time. The weight ratio of the circulating oil to the fresh oil is 1:1 during the cleaning, the hydrogen partial pressure is 8.0 MPa, the reaction temperature is 380°C, and the other process conditions remain unchanged. After each cleaning, the original conditions are restored for continued running. After continued running for 1 year (not including the carbon deposit cleaning time), the sulfur content of the hydrotreated oil is 286 μg / g, and the hydrogen mass fraction is 10.38 mass%. The specific results are shown in Table 3.

[0047] Comparative Example 2

[0048] The raw material A is hydrotreated using the hydrotreating catalyst A, and the process conditions are shown in Table 3. After running for 10 days, the sulfur content of the hydrotreated oil is 25 μg / g, and the hydrogen mass fraction is 11.10 mass%. The specific results are shown in Table 3. Compared with Example 1, it can be seen that the hydrogen consumption of the hydrodesulfurization process can be significantly reduced when the sulfur content of the hydrotreated oil is equivalent.

[0049] Table 3

[0050]

[0051]

[0052] Example 2

[0053] In this example, the hydrotreated oil after running for 10 days in Example 1 is blended with the hydrodeasphalting product at a mass ratio of 45:55 to obtain a low-sulfur marine fuel. The properties of the low-sulfur marine fuel are 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] The hydrogenated product oil of the 10-day operation of Example 1 is blended with low-sulfur residual fuel oil at a mass ratio of 54:46 to obtain low-sulfur marine fuel oil, and the properties of the low-sulfur marine fuel oil are shown in Table 4. As can be seen from Table 4, the viscosity of the blended low-sulfur marine fuel oil 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] The hydrogenated product oil of the 10-day operation of Comparative Example 2 is blended with hydrogenated residual fuel oil at a mass ratio of 45:55 to obtain low-sulfur marine fuel oil, and the properties of the low-sulfur marine fuel oil are shown in Table 4. As can be seen from Table 4, the viscosity of the blended low-sulfur marine fuel oil meets the requirements of RMG180, and the sulfur mass fraction is 0.44% and the hydrogen mass fraction is 11.41%.

[0058] It can be seen that, according to the present application, the low-sulfur marine fuel oil with a lower hydrogen mass fraction can be obtained, as shown in Example 2 and Example 3, and the production cost of the marine fuel oil can be significantly reduced.

[0059] Table 4

[0060] Low sulfur marine fuel properties Example 2 Example 3 Comparative Example 3 Density (20°C), g / cm 3 ]] 0.9467 0.9606 0.9368 50 °C viscosity, 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 application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for producing low-sulfur residual bunker fuel, comprising: (1) the fraction oil with hydrogen mass fraction ≯ 10.5% is mixed with hydrogen and then enters a fixed bed selective hydrodesulfurization reaction zone to react with a hydroprocessing catalyst, the reaction effluent enters a gas-liquid separation zone to carry out gas-liquid separation to obtain a hydrogenated oil, the reaction conditions of the selective hydrodesulfurization reaction zone are: hydrogen partial pressure 0.1-5.9 MPa, reaction temperature 390-460 ℃, hydrogen to oil volume ratio 800-2500, 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%, the initial boiling point of the fraction oil is in the range of 160-350 ℃, the final boiling point is in the range of 300-560 ℃, and the fraction oil is selected from one or more of catalytic diesel, catalytic slurry oil, coal tar, coking diesel, coking wax oil; (2) blending the hydro-up obtained in step (1) with a heavy oil having a sulfur mass fraction ≯ 1.0% and a hydrogen mass fraction ≯ 11.8% to obtain a low-sulfur residual bunker fuel having a sulfur mass fraction ≯ 0.5% and a hydrogen mass fraction ≯ 11.2%, the heavy oil having an initial boiling point in the range of 350-560°C, the heavy oil being selected from the group consisting of a hydro-reduced residual and / or a straight-run residual.

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

3. The method of claim 1, wherein, The resulting hydro-up has a sulfur mass fraction ≯ 0.1% and a hydrogen mass fraction ≯ 11.0%.

4. The method of claim 1, wherein, In step (1), an on-line cleaning of coke stage is further included: the distillate oil and the cycle oil are mixed with hydrogen and then enter a fixed-bed selective hydrodesulfurization reaction zone to contact with a hydroprocessing catalyst, the reaction effluent enters a gas-liquid separation zone for gas-liquid separation, and at least part of the liquid phase returns to the feedstock buffer tank as the cycle oil, and the reaction conditions of the selective hydrodesulfurization reaction zone are as follows: the hydrogen partial pressure is 6.0-12.0 MPa, the reaction temperature is 350-460℃, the hydrogen / oil volume ratio is 200-2500, the volume space velocity is 0.1-4.0 h -1 .

5. The method of claim 4, wherein, The duration of the on-line carbon cleaning stage is 1-10 days.

6. The method of claim 4, wherein, The on-line carbon cleaning is initiated when the hydro-up has a hydro-desulfurization rate < 90%, or is initiated once every 1-6 months.

7. The method of claim 1, wherein, The hydro-treating catalysts comprise one or more, and each independently contain a support and 0-35 mass% of an active metal component.

8. The method of claim 7, wherein, The active metal component is selected from at least one of the group consisting of a nickel-tungsten combination, a nickel-tungsten-cobalt combination, a nickel-molybdenum combination, and a cobalt-molybdenum combination.

9. The method of claim 7, wherein, In each of the hydro-treating catalysts, the active metal component is present in an amount of 0.05-30 mass% as metal oxide.

10. The method of claim 7, wherein, In each of the hydro-treating catalysts, the support is independently selected from at least one of the group consisting of alumina, silica, and titania. In each of the hydro-treating catalysts, the support is independently selected from at least one of the group consisting of alumina, silica, and titania.

11. The method of claim 7, wherein, The average particle diameter of each of the hydroprocessing catalysts is independently 0.5-50 mm, the bulk density of each of the hydroprocessing catalysts is independently 0.3-1.2 g / cm 3 The average pore diameter 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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