Processing method and device for producing low-sulfur marine fuel from residual oil

Abstract

The present invention relates to the field of petrochemical technology, and specifically to a processing method and a processing device for producing low-sulfur marine fuel from residual oil. The processing method comprises: (1) subjecting sulfur-containing heavy oil to hydrodesulfurization treatment, and subjecting the obtained hydrodesulfurized heavy oil to fractionation treatment to obtain hydrotreated residual oil; (2) extracting and separating the hydrotreated residual oil and an extraction solvent to obtain an extraction oil-rich solvent and a raffinate oil-rich solvent; (3) subjecting the extraction oil-rich solvent to a first solvent recovery, and using the obtained extraction oil as a catalytic cracking feedstock; and subjecting the raffinate oil-rich solvent to a second solvent recovery, and using the obtained raffinate oil as a low-sulfur marine fuel feedstock; wherein the extraction solvent is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide. This processing method avoids the cracking and condensation of hydrotreated residual oil under high-temperature distillation conditions, realizes the component separation and high-value-added utilization of the hydrotreated residual oil, simplifies the process, and reduces energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of petrochemical technology, specifically a method for treating hydrocarbon oil using a combination of a hydrotreating process, a distillation process, and an extraction and separation process. More specifically, it relates to a method and apparatus for producing low-sulfur marine fuel from residual oil. Background Art

[0002] From a global perspective, with the continuous development of the shipping industry, the Asia-Pacific region's share of the global marine fuel demand market has continued to grow in recent years, and currently accounts for more than 40% of the global market. The marine fuel demand in the entire Eurasian region currently accounts for about 70% of the world's total, and nearly 90% of the ships on the Asia-Europe route berth at Chinese ports for loading and unloading operations. Therefore, the market demand potential for low-sulfur marine fuel in Chinese ports is huge.

[0003] In order to control the pollution generated during the combustion of marine fuel, the new sulfur emission limit regulations will reduce the sulfur content of global marine fuel oil (hereinafter referred to as "marine fuel") from no more than 3.5wt% to no more than 0.5wt%.

[0004] There are two common methods for producing low-sulfur marine fuel. One is to prioritize raw materials, choosing vacuum residue from low-sulfur paraffinic crude oil for direct blending into low-sulfur marine fuel. The other is to process high-sulfur crude oil through a residue hydrotreating process, with the resulting vacuum residue typically having a sulfur content exceeding 1wt%. Existing low-sulfur marine fuel companies and their production processes show that most companies have residue hydrotreating units. Only some refineries directly produce low-sulfur marine fuel by fine-tuning the type of crude oil they process. The crude oil processing structure of most refineries will not change due to the mass production of low-sulfur marine fuel, and sulfur reduction is typically achieved through the use of supporting residue hydrotreating units.

[0005] After heavy oil hydrotreatment, the residual oil with a boiling point higher than 360°C needs to be distilled out in a vacuum distillation system at a boiling point of 500-560°C, which makes the operating temperature of the vacuum tower higher than 350-360°C. The degree of cracking and condensation of the heavy oil is aggravated, which makes it difficult to control the vacuum degree of the vacuum distillation device. On the other hand, the viscosity of the residual oil is lower after cracking, and the properties of the residual oil deteriorate after condensation, which reduces the fraction suitable as low-sulfur marine fuel.

[0006] CN201110071857.9 discloses a method for processing inferior heavy crude oil, using the atmospheric residue of inferior heavy crude oil as the raw material for a solvent extraction device, and separating it through a solvent extraction process under a supercritical state. CN201710266851.4 discloses a supercritical residue and / or catalytic oil slurry processing system, which extracts the residue and / or mildly oxidized catalytic oil slurry under subcritical conditions, and then recovers the solvent under supercritical conditions, greatly reducing the energy consumption of the device and simplifying the process operation. CN201110071857.9 and CN201710266851.4 both use one or more C3-C5 alkanes or alkenes as solvents. The residue oil after hydrodesulfurization treatment has a low content of colloidal asphaltene. Even if propane solvent is used, there may still be a problem of excessive solubility, resulting in an inability to separate the phases.

[0007] Using alcohols as solvents and adjusting the water content in the solvent can achieve residual oil separation. However, aqueous alcohol solvents require azeotropic distillation for separation and recovery, which consumes a lot of energy. For example, the isopropyl alcohol deasphalting process at PetroChina's Nanchong Refinery and Chemical Plant consumes over 100 kg / ton of standard oil. Even after the extraction column was modified with high-efficiency fillers, the standard oil energy consumption remained as high as 85 kg / ton.

[0008] Therefore, there is an urgent need for a new processing method for producing low-sulfur marine fuel from residual oil. Summary of the Invention

[0009] The purpose of the present invention is to overcome the problems in the prior art that hydrogenated residue oil is prone to reactions leading to cracking and condensation during vacuum distillation, and that the viscosity of hydrogenated residue oil directly blended with marine fuel is too low to produce high-quality low-sulfur marine fuel, and to provide a new processing method and processing device for producing low-sulfur marine fuel from residual oil.

[0010] In order to achieve the above-mentioned object, the first aspect of the present invention provides a processing method for producing low-sulfur marine fuel from residual oil, the processing method comprising the following steps:

[0011] (1) subjecting sulfur-containing heavy oil to hydrodesulfurization treatment, and subjecting the obtained hydrodesulfurized heavy oil to fractional distillation treatment to obtain hydrogenated residual oil;

[0012] (2) extracting and separating the hydrogenated residue oil and the extraction solvent to obtain an extraction oil-rich solvent and a raffinate oil-rich solvent;

[0013] (3) subjecting the solvent rich in extract oil to a first solvent recovery, and using the obtained extract oil as a catalytic cracking feedstock; subjecting the solvent rich in raffinate oil to a second solvent recovery, and using the obtained raffinate oil as a low-sulfur marine fuel feedstock;

[0014] Wherein, the extraction solvent is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide.

[0015] Preferably, the extraction and separation process includes: mixing the hydrogenated residue oil and a portion of the extraction solvent and then introducing the mixture into the upper part of the extraction tower, and introducing the remaining portion of the extraction solvent into the lower part of the extraction tower, wherein the two streams come into contact and undergo the extraction and separation, and the extraction oil-rich solvent is obtained at the top of the extraction tower, and the raffinate oil-rich solvent is obtained at the bottom of the extraction tower.

[0016] Preferably, the volume ratio of the hydrotreated residue oil to the extraction solvent is 1:3-12, preferably 1:5-8.

[0017] Preferably, the volume ratio of the part of the extraction solvent to the remaining part of the extraction solvent is 0.5-6:1-7.5, preferably 0.5-1.5:1-4.5.

[0018] Preferably, the ethane content in the mixed solvent of propane and ethane is 5-55 mol%, preferably 10-55 mol%.

[0019] Preferably, the carbon dioxide content in the mixed solvent of propane and carbon dioxide is 5-45 mol%, preferably 5-40 mol%.

[0020] A second aspect of the present invention provides a processing device for producing low-sulfur marine fuel from residual oil, the processing device comprising: a hydrodesulfurization unit, a fractionation unit, an extraction and separation unit connected in sequence, and a first solvent recovery unit and a second solvent recovery unit connected to the top and bottom of the extraction and separation unit, respectively;

[0021] The hydrodesulfurization unit is used to hydrodesulfurize sulfur-containing heavy oil to obtain hydrodesulfurized heavy oil;

[0022] The fractionation unit is used to fractionate the hydrodesulfurized heavy oil to obtain hydrogenated residue oil;

[0023] The extraction and separation unit is used to extract and separate the hydrotreated residue oil and the extraction solvent to obtain an extraction oil-rich solvent and a raffinate oil-rich solvent; wherein the extraction solvent is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide;

[0024] The first solvent recovery unit is used to recover the first solvent from the solvent rich in extracted oil to obtain extracted oil and a first solvent; the second solvent recovery unit is used to recover the second solvent from the solvent rich in raffinate oil to obtain raffinate oil and a second solvent;

[0025] The extracted oil is used as a catalytic cracking raw material; the raffinate oil is used as a low-sulfur marine fuel raw material.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] (1) The processing method provided by the present invention uses sulfur-containing heavy oil as raw material, undergoes hydrodesulfurization treatment and fractionation treatment, and extracts and separates the obtained hydrogenated residue oil and a specific extraction solvent. The obtained solvent rich in extracted oil and the obtained solvent rich in raffinate oil are each independently subjected to solvent separation. The obtained extracted oil is used as a catalytic cracking feedstock, and the obtained raffinate oil is used as a low-sulfur marine fuel feedstock. That is, the processing method provided by the present invention uses solvent extraction separation instead of vacuum distillation, avoids the cracking and condensation of the hydrogenated residue oil under high-temperature distillation conditions, and realizes the component separation and high-value-added utilization of the hydrogenated residue oil;

[0028] (2) The present invention adopts a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide as an extraction solvent, and performs selective extraction and separation through solvent extraction to obtain an extraction oil rich in saturates as a catalytic cracking raw material, and uses the obtained raffinate oil as a low-sulfur marine fuel raw material, thereby increasing the viscosity of the low-sulfur marine fuel and realizing high added value utilization of the raffinate oil; at the same time, the processing method simplifies the process, reduces energy consumption, and saves production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention provides a schematic structural diagram of a processing device for producing low-sulfur marine fuel from residual oil.

[0030] Description of Reference Numerals

[0031] I, hydrodesulfurization unit II, fractionation unit III, extraction separation unit IV, first solvent recovery unit V, second solvent recovery unit 1, sulfur-containing heavy oil 2, hydrodesulfurized heavy oil 3, hydrogenated residue 4, extraction solvent

[0032] 4-i, part of the extraction solvent 4-ii, the remaining part of the extraction solvent 5, rich in extraction oil solvent

[0033] 6. Raffinate oil-rich solvent 7. Extracted oil 8. First solvent 9. Raffinate oil 10. Second solvent DETAILED DESCRIPTION

[0034] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0035] In the present invention, unless otherwise specified, the terms "first" and "second" do not indicate a sequential order or limit the materials or steps. They are used only to distinguish or indicate that they are not the same materials or steps. For example, "first solvent recovery" and "second solvent recovery" are used only to indicate that they are not the same solvent recovery; similarly, "first solvent" and "second solvent" are used only to indicate that they are not the same solvent.

[0036] In the present invention, unless otherwise specified, the top of the container refers to the position of 0-10% from the top to the bottom of the container; the upper part of the container refers to the position of 10-40% from the top to the bottom of the container; the middle part of the container refers to the position of 40-60% from the top to the bottom of the container; the lower part of the container refers to the position of 60-90% from the top to the bottom of the container; and the bottom of the container refers to the position of 90-100% from the top to the bottom of the container.

[0037] A first aspect of the present invention provides a method for producing low-sulfur marine fuel from residual oil, the method comprising the following steps:

[0038] (1) subjecting sulfur-containing heavy oil to hydrodesulfurization treatment, and subjecting the obtained hydrodesulfurized heavy oil to fractional distillation treatment to obtain hydrogenated residual oil;

[0039] (2) extracting and separating the hydrogenated residue oil and the extraction solvent to obtain an extraction oil-rich solvent and a raffinate oil-rich solvent;

[0040] (3) subjecting the solvent rich in extract oil to a first solvent recovery, and using the obtained extract oil as a catalytic cracking feedstock; subjecting the solvent rich in raffinate oil to a second solvent recovery, and using the obtained raffinate oil as a low-sulfur marine fuel feedstock;

[0041] Wherein, the extraction solvent is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide.

[0042] In some embodiments of the present invention, preferably, in step (1), the sulfur content of the sulfur-containing heavy oil is 1-8 wt%, the residual carbon value is 5-20 wt%, and the asphaltene content is 0.5-15 wt%.

[0043] In the present invention, the sulfur-containing heavy oil has a wide range of choices, as long as the physical properties of the sulfur-containing heavy oil meet the above-mentioned limitations. Preferably, the sulfur-containing heavy oil includes but is not limited to atmospheric residue oil, vacuum residue oil, etc.

[0044] In the present invention, the dehydrogenation and desulfurization process includes: contacting the sulfur-containing heavy oil with hydrogen in the presence of an optional hydrogenation catalyst and performing a hydrodesulfurization process to obtain the hydrodesulfurized heavy oil. The hydrogenation catalyst includes but is not limited to a fixed bed hydrogenation catalyst or a moving bed hydrogenation catalyst.

[0045] In some embodiments of the present invention, preferably, the conditions of the hydrodesulfurization treatment include: a pressure of 10-20 MPa, for example, 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, and any value in a range consisting of any two values, preferably 10-18 MPa; a temperature of 300-470°C, for example, 300°C, 350°C, 370°C, 400°C, 420°C, 450°C, 470°C, and any value in a range consisting of any two values, preferably 370-450°C; a hydrogen-to-oil volume ratio of 600-2000, for example, 600, 800, 1000, 1200, 1500 and 2000, and any value in a range consisting of any two values, preferably 600-1200; a volume space velocity of 0.2-3h -1 , for example, 0.2h -1 , 0.5h -1 , 0.8h -1 , 1h -1 , 1.2h -1 , 1.5h -1 , 2h -1 , 3h -1 , and any value in the range of any two values, preferably 0.2-1.5h -1 In the present invention, pressure refers to gauge pressure; hydrogen-to-oil volume ratio refers to the volume ratio of hydrogen to sulfur-containing heavy oil; and volume space velocity refers to the volume space velocity of hydrogen.

[0046] In the present invention, the fractionation process comprises: fractionating the hydrodesulfurized heavy oil to obtain gas products, light oil and hydrogenated residual oil. Preferably, the conditions of the fractionation treatment include: a tower top temperature of 90-150°C, for example, 90°C, 100°C, 110°C, 120°C, 130°C, 150°C, and any value in a range consisting of any two numerical values, preferably 100-120°C; a tower bottom temperature of 350-450°C, for example, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 450°C, and any value in a range consisting of any two numerical values, preferably 360-390°C; and a pressure of 0.05-0.1MPa, for example, 0.05MPa, 0.07MPa, 0.08MPa, 0.09MPa, 0.1MPa, and any value in a range consisting of any two numerical values, preferably 0.07-0.09MPa.

[0047] In the present invention, the hydrogenated residue refers to sulfur-containing heavy oil that has been subjected to hydrodesulfurization treatment and then fractionated in an atmospheric distillation tower, and a hydrogenated residue with a distillation range of ≥360°C is obtained at the bottom of the tower. The fraction with a boiling point of not less than 360°C needs to be distilled out in a vacuum distillation system at a maximum temperature of 500-560°C. The degree of cracking of the heavy oil is aggravated, which, on the one hand, makes it difficult to control the vacuum degree of the vacuum distillation device, and on the other hand, the viscosity of the residue is low after cracking, and the fraction suitable for use as low-sulfur marine fuel is reduced. The present invention subjects the hydrogenated residue after hydrodesulfurization treatment to low-temperature solvent extraction and separation, uses the extracted oil as a catalytic cracking feedstock, and uses the raffinate oil with a higher viscosity as a low-sulfur marine fuel feedstock, thereby realizing high value-added utilization of the hydrogenated residue.

[0048] In some embodiments of the present invention, preferably, the physical properties of the hydrotreated residue oil meet the following requirements: sulfur content ≤ 0.7 wt%; distillation range ≥ 360°C; carbon residue value 2-6 wt%; resin content 5-20 wt%; asphaltene content 0.1-4 wt%.

[0049] In the present invention, in order to achieve selective extraction and separation of various components in hydrogenated residue oil, preferably, the extraction and separation process includes: mixing the hydrogenated residue oil and a portion of the extraction solvent and then introducing the mixture into the upper part of the extraction tower, and introducing the remaining portion of the extraction solvent into the lower part of the extraction tower, wherein the two streams come into contact and undergo the extraction and separation, obtaining the extraction oil-rich solvent at the top of the extraction tower and obtaining the raffinate oil-rich solvent at the bottom of the extraction tower.

[0050] In the present invention, unless otherwise specified, the extraction tower may be a well-known rotary disc tower, sieve plate tower or packed tower, or an empty tower, with no limitation on form.

[0051] In the present invention, unless otherwise specified, the extraction solvent is divided into the partial extraction solvent and the remaining extraction solvent.

[0052] In some embodiments of the present invention, the volume ratio of the hydrotreated residue to the extraction solvent is preferably 1:3-12, for example, 1:3, 1:5, 1:6, 1:7, 1:8, 1:10, 1:12, and any value within a range consisting of any two values, preferably 1:5-8. In the present invention, when the volume ratio is greater than 1:3, the amount of extraction solvent is too small, which can easily lead to the absence of a phase interface and inability to achieve separation; when the volume ratio is less than 1:12, the excessive amount of solvent used results in high recovery energy consumption, resulting in reduced technical and economic efficiency.

[0053] In some embodiments of the present invention, preferably, the volume ratio of the part of the extraction solvent to the remaining part of the extraction solvent is 0.5-6:1-7.5, for example, 0.5:1, 0.5:2, 0.5:4.5, 0.5:7.5, 1:1, 1:1.5, 1:4.5, 1.5:1, 1.5:1.5, 1.5:4.5, 2:1, 2:4, 3:4, 3:5, 5:1, 5:7.5, 6:1, 6:7.5, and any value in a range consisting of any two values, preferably 0.5-1.5:1-4.5. In the present invention, the preferred volume ratio can achieve effective dispersion of the raw oil droplets, improve extraction efficiency, and reduce the amount of extraction solvent used and the energy consumption of solvent recovery.

[0054] In some embodiments of the present invention, the extraction solvent is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide.

[0055] In some embodiments of the present invention, further preferably, the ethane content in the propane-ethane mixed solvent is 5-55 mol%, for example, 5 mol%, 10 mol%, 15 mol%, 20 wt%, 30 mol%, 40 mol%, 45 mol%, 50 mol%, 55 mol%, and any value in a range consisting of any two of these values, preferably 10-55 mol%. In the present invention, only by adopting the preferred conditions can the hydroprocessing residue oil be effectively phase-separated to obtain an extract oil-rich solvent and a raffinate oil-rich solvent.

[0056] In some embodiments of the present invention, it is further preferred that the carbon dioxide content in the propane and carbon dioxide mixed solvent is 5-45 mol%, for example, 5 mol%, 10 mol%, 15 mol%, 20 mol%, 25 mol%, 35 mol%, 40 mol%, 45 mol%, and any value in a range consisting of any two of these values, preferably 5-40 mol%. In the present invention, only by adopting the preferred conditions can the hydrotreated residue oil be effectively phase-separated to obtain an extract oil-rich solvent and a raffinate oil-rich solvent.

[0057] In some embodiments of the present invention, preferably, the conditions for the extraction and separation include: a pressure of 4.5-16 MPa, for example, 4.5 MPa, 5 MPa, 7 MPa, 10 MPa, 16 MPa, and any value in a range consisting of any two numerical values, preferably 4.5-10 MPa; a tower top temperature of 30-100°C, for example, 30°C, 40°C, 60°C, 80°C, 90°C, 100°C, and any value in a range consisting of any two numerical values, preferably 40-90°C; a tower bottom temperature of 25-90°C, for example, 25°C, 30°C, 40°C, 60°C, 70°C, 80°C, 90°C, and any value in a range consisting of any two numerical values, preferably 30-80°C.

[0058] In the present invention, the first solvent recovery is intended to separate the solvent rich in extraction oil to obtain extraction oil and the first solvent. Preferably, the first solvent recovery method includes but is not limited to supercritical solvent recovery, steam stripping recovery, flash evaporation, etc.

[0059] In the present invention, the second solvent recovery is to separate the raffinate oil-rich solvent to obtain raffinate oil and the second solvent. Preferably, the second solvent recovery method includes but is not limited to steam stripping recovery, flash evaporation, etc.

[0060] In some embodiments of the present invention, preferably, the conditions for recovering the first solvent and recovering the second solvent each independently include: a temperature of 100-200°C, for example, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, and any value in a range consisting of any two numerical values, preferably 120-160°C; a pressure of 0.2-1MPa, for example, 0.2MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 1MPa, and any value in a range consisting of any two numerical values, preferably 0.5-0.8MPa.

[0061] In some embodiments of the present invention, preferably, the physical properties of the extracted oil meet the following requirements: mass yield ≥ 50%, preferably 60-90%; density (20°C) 0.88-0.92 g / cm 3 The carbon residue is 0.01-2 wt%; the saturates content is 60-80 wt%; and the total metal content is 0.1-5 μg / g. In the present invention, the saturates content refers to the saturated hydrocarbon content, and the total metal content refers to the sum of the contents of Ni, V, Fe, Na, and Ca.

[0062] In some embodiments of the present invention, preferably, the physical properties of the raffinate oil meet the following requirements: mass yield ≤ 50%, preferably 10-40%; density (20°C) 0.94-1 g / cm 3;(80℃) viscosity is 70-900mm 2 / s; (100℃) viscosity is 30-300mm 2 / s; carbon residue value is 4-18wt%; asphaltene content is 0.5-5wt%; total metal content is 20-200μg / g.

[0063] In the present invention, unless otherwise specified, the density parameter is measured using the SH / T 0604 method; the viscosity parameter is measured using the GB / T 11137 method; the carbon residue value parameter is measured using the SH / T 0170 method; the four component parameters are measured using the SH / T0753 method; and the total metal content parameter is measured using an ICP spectrometer method.

[0064] In some embodiments of the present invention, preferably, the processing method further comprises: independently returning the first solvent obtained by recovering the first solvent and the second solvent obtained by recovering the second solvent as circulating extraction solvents and mixing them into the extraction solvent.

[0065] The second aspect of the present invention provides a structural diagram of a processing device for producing low-sulfur marine fuel from residual oil. Figure 1 As shown, the processing device includes: a hydrodesulfurization unit I, a fractionation unit II, an extraction and separation unit III connected in sequence, and a first solvent recovery unit IV and a second solvent recovery unit V connected to the top and bottom of the extraction and separation unit III respectively;

[0066] The hydrodesulfurization unit 1 is used to hydrodesulfurize the sulfur-containing heavy oil 1 to obtain the hydrodesulfurized heavy oil 2;

[0067] The fractionation unit II is used to fractionate the hydrodesulfurized heavy oil 2 to obtain hydrogenated residue 3;

[0068] The extraction and separation unit III is used to extract and separate the hydrotreated residue oil 3 and the extraction solvent 4 to obtain an extraction oil-rich solvent 5 and a raffinate oil-rich solvent 6; wherein the extraction solvent 4 is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide;

[0069] The first solvent recovery unit IV is used to recover the first solvent from the solvent rich in extracted oil 5 to obtain extracted oil 7 and a first solvent 8; the second solvent recovery unit V is used to recover the second solvent from the solvent rich in raffinate oil 6 to obtain raffinate oil 9 and a second solvent 10;

[0070] The extracted oil 7 is used as a catalytic cracking raw material; and the raffinate oil 9 is used as a low-sulfur marine fuel raw material.

[0071] According to the present invention, preferably, Figure 1As shown, the extraction solvent 4 is divided into a part of the extraction solvent 4-i and the remaining part of the extraction solvent 4-ii, wherein the hydrogenated residue oil 3 and the part of the extraction solvent 4-i are mixed and enter the upper part of the extraction and separation unit III, and the remaining part of the extraction solvent 4-ii enters the lower part of the extraction and separation unit III, and the two streams contact and perform the extraction and separation.

[0072] According to the present invention, preferably, Figure 1 As shown, the top of the first solvent recovery unit IV and the top of the second solvent recovery unit V are respectively connected to the extraction separation unit III, for returning the first solvent 8 and the second solvent 10 independently as circulating extraction solvents and mixing them into the extraction solvent 4.

[0073] According to a particularly preferred embodiment of the present invention, a method for processing residual oil to produce low-sulfur marine fuel comprises the following steps:

[0074] (1) subjecting sulfur-containing heavy oil to hydrodesulfurization treatment, and subjecting the obtained hydrodesulfurized heavy oil to fractional distillation treatment to obtain hydrogenated residual oil;

[0075] (2) mixing the hydrogenated residue oil and a portion of the extraction solvent and then feeding the mixture into the upper part of the extraction tower, and feeding the remaining portion of the extraction solvent into the lower part of the extraction tower, wherein the two streams are in contact and subjected to the extraction separation, and the extraction oil-rich solvent is obtained at the top of the extraction tower, and the raffinate oil-rich solvent is obtained at the bottom of the extraction tower;

[0076] (3) subjecting the solvent rich in extract oil to a first solvent recovery, and using the obtained extract oil as a catalytic cracking feedstock; subjecting the solvent rich in raffinate oil to a second solvent recovery, and using the obtained raffinate oil as a low-sulfur marine fuel feedstock;

[0077] Wherein, the extraction solvent is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide; the ethane content in the mixed solvent of propane and ethane is 10-55 mol%; the carbon dioxide content in the mixed solvent of propane and carbon dioxide is 5-40 mol%;

[0078] The volume ratio of the hydrogenated residue oil to the extraction solvent is 1:5-8; the volume ratio of the part of the extraction solvent to the remaining part of the extraction solvent is 0.5-1.5:1-4.5;

[0079] The extraction and separation conditions include: a pressure of 4.5-10 MPa; a tower top temperature of 40-90° C.; and a tower bottom temperature of 30-80° C.

[0080] The present invention will be described in detail below through examples.

[0081] Example 1

[0082] The schematic diagram of the structure of the processing unit for producing low sulfur marine fuel from residual oil is as follows: Figure 1 As shown, the processing device includes: a hydrodesulfurization unit I, a fractionation unit II, an extraction and separation unit III connected in sequence, and a first solvent recovery unit IV and a second solvent recovery unit V connected to the top and bottom of the extraction and separation unit III respectively;

[0083] Among them, the extraction solvent 4 is divided into a part of the extraction solvent 4-i and the remaining part of the extraction solvent 4-ii. The hydrogenated residue oil 3 and the part of the extraction solvent 4-i are mixed and enter the upper part of the extraction and separation unit III, and the remaining part of the extraction solvent 4-ii enters the lower part of the extraction and separation unit III. The two streams contact and undergo the extraction and separation; the top of the first solvent recovery unit IV and the top of the second solvent recovery unit V are respectively connected to the extraction and separation unit III.

[0084] A processing method for producing low-sulfur marine fuel from residual oil, the processing method comprising the following steps:

[0085] (1) The sulfur-containing heavy oil (property parameters are shown in Table 1) was subjected to hydrodesulfurization treatment (pressure 16 MPa, temperature 410 °C, hydrogen-to-oil volume ratio 700, volume space velocity 0.5 h -1 ), the obtained hydrodesulfurized heavy oil was fractionated (tower top temperature was 120°C, tower bottom temperature was 370°C, and pressure was 0.05MPa) to obtain hydrogenated residue A (property parameters are shown in Table 1);

[0086] (2) using a mixed solvent of propane and ethane as an extraction solvent, wherein the ethane content in the mixed solvent of propane and ethane is 20 mol%; wherein the above-mentioned hydrogenated residue oil and a portion of the extraction solvent are mixed and then introduced into the upper part of the extraction tower, and the remaining portion of the extraction solvent is introduced into the lower part of the extraction tower, the two streams are contacted and subjected to extraction and separation, and a solvent rich in extraction oil is obtained at the top of the extraction tower, and a solvent rich in raffinate oil is obtained at the bottom of the extraction tower;

[0087] The volume ratio of the hydrotreated residue oil to the extraction solvent is 1:6; the volume ratio of the partial extraction solvent to the remaining extraction solvent is 2:4;

[0088] The extraction separation conditions include: pressure of 5 MPa; tower top temperature of 85°C; tower bottom temperature of 75°C;

[0089] (3) subjecting the above-mentioned solvent rich in extraction oil to a first solvent recovery (temperature of 150° C., pressure of 0.5 MPa) to obtain extraction oil S1 and a first solvent; subjecting the above-mentioned solvent rich in raffinate oil to a second solvent recovery (temperature of 160° C., pressure of 0.5 MPa) to obtain raffinate oil P1 and a second solvent; and returning the above-mentioned first solvent and second solvent independently as circulating extraction solvents and mixing them into the extraction solvent;

[0090] Among them, the extracted oil S1 is used as the catalytic cracking feedstock; the raffinate oil P1 is used as the low-sulfur marine fuel feedstock; the physical properties of the extracted oil S1 and the raffinate oil P1 are listed in Table 2.

[0091] Example 2

[0092] According to the processing device provided in Example 1;

[0093] According to the processing method provided in Example 1, the difference is that in step (2),

[0094] The ethane content in the propane and ethane mixed solvent was replaced with 50 mol%;

[0095] The volume ratio of the above-mentioned hydrotreated residue oil and the extraction solvent is replaced with 1:8; the volume ratio of part of the extraction solvent and the remaining part of the extraction solvent is replaced with 3:5;

[0096] The extraction separation conditions include: pressure of 8 MPa; tower top temperature of 75°C; tower bottom temperature of 65°C;

[0097] The other conditions were the same, and the physical properties of the obtained extract oil S2 and raffinate oil P2 were listed in Table 2.

[0098] Example 3

[0099] According to the processing device provided in Example 1;

[0100] According to the processing method provided in Example 1, the difference is that in step (2),

[0101] The extraction solvent is replaced with a mixed solvent of propane and carbon dioxide, and the content of carbon dioxide in the mixed solvent of propane and carbon dioxide is 10 mol%;

[0102] The extraction separation conditions include: pressure of 5 MPa; tower top temperature of 80°C; tower bottom temperature of 70°C;

[0103] The other conditions were the same, and the physical properties of the obtained extract oil S3 and raffinate oil P3 were listed in Table 2.

[0104] Example 4

[0105] According to the processing device provided in Example 1;

[0106] According to the processing method provided in Example 1, the difference is that in step (2),

[0107] The extraction solvent is replaced with a mixed solvent of propane and carbon dioxide, and the content of carbon dioxide in the mixed solvent of propane and carbon dioxide is 30 mol%;

[0108] The volume ratio of the above-mentioned hydrogenated residue oil to the extraction solvent is 1:7; the volume ratio of part of the extraction solvent to the remaining part of the extraction solvent is 3:4;

[0109] The extraction separation conditions include: pressure of 9 MPa; tower top temperature of 80°C; tower bottom temperature of 70°C;

[0110] The other conditions were the same, and the physical properties of the obtained extract oil S4 and raffinate oil P4 were listed in Table 2.

[0111] Example 5

[0112] According to the processing device provided in Example 1;

[0113] According to the processing method provided in Example 1, the difference is that in step (2),

[0114] The volume ratio of the above-mentioned hydrogenated residue oil and the extraction solvent is 1:10;

[0115] The other conditions were the same, and the physical properties of the obtained extract oil S5 and raffinate oil P5 were listed in Table 2.

[0116] Example 6

[0117] The processing device provided in Example 1 is different in that the extraction solvent is directly extracted and separated from the above-mentioned hydrogenated residue oil;

[0118] According to the processing method provided in Example 1, the difference is that in step (2),

[0119] Directly performing solvent separation on the hydrogenated residue oil and the extraction solvent, i.e., the extraction solvent is no longer divided into a portion of the extraction solvent having a volume ratio of 2:4 and a remaining portion of the extraction solvent;

[0120] The other conditions were the same, and the physical properties of the obtained extract oil S6 and raffinate oil P6 were listed in Table 2.

[0121] Example 7

[0122] According to the processing device provided in Example 1;

[0123] According to the processing method provided in Example 1, the difference is that in step (2),

[0124] The ethane content in the propane and ethane mixed solvent was replaced with 60 mol%;

[0125] When other conditions were the same, it was found that the ethane in the extraction separation unit was partially vaporized, the amount of liquid solvent was small, and phase separation could not be achieved.

[0126] Example 8

[0127] According to the processing device provided in Example 1;

[0128] According to the processing method provided in Example 1, the difference is that in step (2),

[0129] The ethane content in the propane and ethane mixed solvent was replaced with 1 mol%;

[0130] The volume ratio of the above-mentioned hydrotreated residue oil and the extraction solvent is replaced with 1:7; the volume ratio of part of the extraction solvent and the remaining part of the extraction solvent is replaced with 3:4;

[0131] The extraction separation conditions include: pressure of 5 MPa; tower top temperature of 99°C; tower bottom temperature of 89°C;

[0132] Other conditions are the same. Since the propane solvent still has a strong dissolving ability under the condition of exceeding the supercritical temperature, it almost completely dissolves the above-mentioned hydrogenated residue oil. The materials in the extraction and separation unit are not phase-separated and phase separation cannot be achieved.

[0133] Example 9

[0134] According to the processing device provided in Example 3;

[0135] According to the processing method provided in Example 3, the difference is that in step (2),

[0136] The carbon dioxide content in the propane and carbon dioxide mixed solvent is replaced with 50 mol%;

[0137] When other conditions were the same, it was found that the carbon dioxide in the extraction separation unit was partially vaporized, the amount of liquid solvent was small, and phase separation could not be achieved.

[0138] Example 10

[0139] According to the processing device provided in Example 3;

[0140] According to the processing method provided in Example 3, the difference is that in step (2),

[0141] The carbon dioxide content in the propane and carbon dioxide mixed solvent was replaced with 2 mol%;

[0142] When other conditions are the same, the mixed solvent has a strong dissolving ability, the raffinate oil yield is less than 5%, and the extraction separation unit is prone to miscibility, making stable separation difficult.

[0143] Comparative Example 1

[0144] The hydrodesulfurized residue A prepared in Example 1 was separated by vacuum distillation to obtain heavy distillate oil and vacuum residue oil; the yield of the low-sulfur marine fuel raw material was 45.6%. In addition, due to the high vacuum distillation temperature, the hydrodesulfurized residue oil showed agglomeration and fouling during the vacuum distillation process due to its stability.

[0145] Comparative Example 2

[0146] Isopropanol was used as solvent to extract and separate the residue B (property parameters are listed in Table 1) (Reference: Yu Jie. Modification of extraction tower and application of flat ring packing in extraction tower [J]. Lubricating Oil, 2007(02):13-18). The operating conditions were as follows: the weight ratio of solvent to residue B was 3.1:1, the extraction temperature was 110-125℃, the water content in the solvent was 1-2wt%, the mass yield of deasphalted oil was 46%, the residual carbon value was 2.5%, and the density was 893.7kg / m 3 Because the solvent isopropyl alcohol contains water, a complex azeotropic distillation method is required to purify the isopropyl alcohol solvent, resulting in high energy consumption for the entire device, with standard oil energy consumption as high as 85 kg / ton.

[0147] Comparative Example 3

[0148] According to the processing device of Example 1;

[0149] The processing method of Example 1 is the same as that of Example 1, except that in step (2),

[0150] The extraction solvent was replaced with a mixed solvent of propane and ethanol, and the ethanol content in the mixed solvent was 20 mol%, while the other conditions remained the same. Since the critical temperature of ethanol is 243.1°C and the critical pressure is 6.38 MPa, there is a partial gas phase at the extraction temperature and pressure, and the device cannot operate stably.

[0151] Comparative Example 4

[0152] According to the processing device of Example 3;

[0153] The processing method of Example 3 is the same, except that in step (2),

[0154] The extraction solvent is replaced with a mixed solvent of ethane and carbon dioxide, and the carbon dioxide content in the mixed solvent is 10 mol%. Other conditions are the same. The dissolving capacity of the mixed solvent of ethane and carbon dioxide is low, and the extraction oil yield is less than 10% or extraction cannot be achieved, affecting the technical and economic efficiency.

[0155] Table 1

[0156] Sulfur heavy oil Hydrogenated Residue A Residue B <![CDATA[Density at 20 °C / (kg / m 3 )]]> 0.9805 0.9205 0.903 <![CDATA[100℃ kinematic viscosity / (mm 2 / s)]]> 300 10.39 / <![CDATA[Kinematic viscosity at 80℃ / (mm 2 / s)]]> 1600 18.25 / Carbon residue value / wt% 15.0 2.7 5.44 Saturated hydrocarbons / wt% / 56.0 / Aromatics / wt% / 32.7 / Colloid / wt% / 10.4 / Asphaltene / wt% 5.0 0.9 / Carbon / wt% / 87.26 / Hydrogen / wt% / 12.2 / Sulfur / wt% 3.21 0.34 / Nitrogen / wt% / 0.12 / Iron / (mg / kg) 12.9 7.4 / Nickel / (mg / kg) 35.4 9.9 / Vanadium / (mg / kg) 29.7 9.1 / Sodium / (mg / kg) 4.2 1.1 / Calcium / (mg / kg) 6.4 1.0 /

[0157] Table 2

[0158]

[0159]

[0160] Table 2

[0161]

[0162] It can be seen from the data in Table 2 that, compared with Comparative Examples 1-2, Examples 1-6 adopt the method of the present invention, and by regulating the ratio of the mixed solvent and the extraction temperature, phase separation of the hydrogenated residue oil can be achieved. The obtained extracted oil has a high content of crackable saturated fractions and is a high-quality catalytic cracking feedstock. At the same time, the obtained raffinate oil has a low sulfur content and a greatly improved viscosity relative to the hydrogenated residue oil, which is conducive to the production of higher quality low-sulfur marine fuel feedstock.

[0163] Furthermore, the method of the present invention still falls within the scope of propane solvent deasphalting. GB 30251-2013, a refinery unit product energy consumption limit, requires that the energy consumption for solvent deasphalting standard oil be less than 26 kg / ton. Therefore, while achieving hydroresidue separation, the method of the present invention consumes far less energy than alcohol solvent extraction separation methods.

[0164] Compared with Example 1, Example 5 adopts a technical solution in which the weight ratio of hydrogenated residue oil to extraction solvent is not within the preferred protection range. The yield of the obtained extracted oil S5 is slightly higher than that of Example 1, but the energy consumption is higher.

[0165] Compared with Example 1, Example 6 adopts the technical solution of not dividing the extraction solvent into two streams. The yield of the extracted oil S6 obtained is 3.5% lower than that of Example 1, and the energy consumption is slightly higher, and the economic efficiency is lower.

[0166] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for producing low-sulfur marine fuel from residual oil, characterized in that: The processing method comprises the following steps: (1) subjecting sulfur-containing heavy oil to hydrodesulfurization treatment, and fractionating the obtained hydrodesulfurized heavy oil to obtain hydrogenated residue oil; (2) extracting and separating the hydrogenated residue oil and the extraction solvent to obtain an extraction oil-rich solvent and a raffinate oil-rich solvent; (3) recovering the solvent rich in extracted oil through a first solvent, and using the obtained extracted oil as a catalytic cracking feedstock; recovering the solvent rich in raffinate oil through a second solvent, and using the obtained raffinate oil as a low-sulfur marine fuel feedstock; The extraction solvent is selected from a mixed solvent of propane and ethane, or a mixed solvent of propane and carbon dioxide; the ethane content in the mixed solvent of propane and ethane is 5-55 mol%; the carbon dioxide content in the mixed solvent of propane and carbon dioxide is 5-45 mol%; the conditions for the extraction separation include: pressure of 4.5-16 MPa, tower top temperature of 30-100°C, and tower bottom temperature of 25-90°C.

2. The processing method according to claim 1, wherein: In step (1), the physical properties of the sulfur-containing heavy oil meet the following requirements: sulfur content of 1-8 wt%, carbon residue of 5-20 wt%, and asphaltene content of 0.5-15 wt%.

3. The processing method according to claim 2, wherein: The conditions of the hydrodesulfurization treatment include: pressure of 10-20 MPa; temperature of 300-470°C; hydrogen-to-oil volume ratio of 600-2000; volume space velocity of 0.2-3h -1 .

4. The processing method according to claim 3, wherein: The hydrodesulfurization treatment conditions include: pressure of 10-18 MPa; temperature of 370-450°C; hydrogen-to-oil volume ratio of 600-1200; volume space velocity of 0.2-1.5h -1 .

5. The processing method according to claim 2, wherein: The conditions of the fractionation treatment include: tower top temperature of 90-150° C.; tower bottom temperature of 350-450° C.; and pressure of 0.05-0.1 MPa.

6. The processing method according to claim 5, wherein: The conditions of the fractionation treatment include: a tower top temperature of 100-120° C.; a tower bottom temperature of 360-390° C.; and a pressure of 0.07-0.09 MPa.

7. The processing method according to claim 2, wherein: The physical properties of the hydrogenated residue oil meet the following requirements: sulfur content ≤ 0.7 wt%; distillation range ≥ 360° C.; carbon residue value 2-6 wt%; resin content 5-20 wt%; and asphaltene content 0.1-4 wt%.

8. The processing method according to claim 1, wherein: The extraction and separation process includes: mixing the hydrogenated residue oil and a portion of the extraction solvent and then feeding the mixture into the upper part of the extraction tower; feeding the remaining portion of the extraction solvent into the lower part of the extraction tower; the two streams come into contact and undergo the extraction and separation; obtaining the extraction oil-rich solvent at the top of the extraction tower and obtaining the raffinate oil-rich solvent at the bottom of the extraction tower.

9. The processing method according to claim 8, wherein: The volume ratio of the hydrogenated residue oil to the extraction solvent is 1:3-12; The volume ratio of the part of the extraction solvent to the remaining part of the extraction solvent is 0.5-6:1-7.

5.

10. The processing method according to claim 9, wherein: The volume ratio of the hydrogenated residue oil to the extraction solvent is 1:5-8; The volume ratio of the part of the extraction solvent to the remaining part of the extraction solvent is 0.5-1.5:1-4.

5.

11. The processing method according to claim 1, wherein: The ethane content in the mixed solvent of propane and ethane is 10-55 mol%; The carbon dioxide content in the mixed solvent of propane and carbon dioxide is 5-40 mol%; The extraction and separation conditions include: pressure of 4.5-10 MPa; tower top temperature of 40-90° C.; and tower bottom temperature of 30-80° C.

12. The processing method according to claim 1, wherein: The physical properties of the extracted oil meet the following requirements: mass yield ≥ 50%; density (20°C) 0.88-0.92 g / cm 3 ; The carbon residue value is 0.01-2wt%; the saturated fraction content is 60-80wt%; the total metal content is 0.1-5μg / g; The physical properties of the raffinate oil meet the following requirements: mass yield ≤ 50%; density (20°C) 0.94-1 g / cm 3 ;(80℃) viscosity is 70-900mm 2 / s; (100℃) viscosity is 30-300mm 2 / s; carbon residue value is 4-18wt%; asphaltene content is 0.5-5wt%; total metal content is 20-200μg / g.

13. The processing method according to claim 12, wherein: The physical properties of the extracted oil meet the following requirements: mass yield is 60-90%; The physical property parameters of the raffinate oil meet the following requirements: mass yield of 10-40%.

14. The processing method according to claim 1, wherein: The conditions for the first solvent recovery and the second solvent recovery each independently include: The temperature is 100-200℃; the pressure is 0.2-1MPa.

15. The processing method according to claim 14, wherein: The conditions for the first solvent recovery and the second solvent recovery each independently include: The temperature is 120-160℃; the pressure is 0.5-0.8MPa.

16. The processing method according to any one of claims 1 to 15, wherein: The processing method further includes: independently returning the first solvent obtained by recovering the first solvent and the second solvent obtained by recovering the second solvent as circulating extraction solvents and mixing them into the extraction solvent.

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