A process for hydro-upgrading of a fischer-tropsch synthesis oil

Abstract

The present application relates to a kind of methods for upgrading of Fischer-Tropsch synthesis oil, including Fischer-Tropsch synthesis oil sequentially into hydrogenation guard reactor and hydrofining reactor, and hydrogenation guard catalyst and hydrofining catalyst are contacted to carry out olefin saturation and hydrodeoxygenation reaction, the reaction effluent of hydrofining reactor is separated, and naphtha fraction, light white oil fraction, liquid wax fraction and column bottom wax oil fraction are obtained.The present application optimizes the proportion and grading scheme of catalyst loading of hydrogenation guard reactor and hydrofining reactor, effectively controls the reasonable distribution of temperature rise in reactor, avoids the risk of carbon deposition and coking caused by local reaction intense, and improves the stable operation period of device.

Description

Technical Field

[0001] The present invention relates to the technical field of Fischer-Tropsch synthetic oil processing, and in particular to a method for hydrogenating and upgrading Fischer-Tropsch synthetic oil. Background Art

[0002] With the development of the national economy, my country's oil consumption has shown a rapid upward trend, and its dependence on foreign crude oil has increased year by year. At the same time, increasingly stringent environmental regulations have placed ever-stricter demands on the composition, impurity content, and pollutant emissions of engine fuels during processing. However, as a non-renewable energy source, oil is facing a crisis of increasing depletion, and crude oil quality is deteriorating, with a growing trend towards inferior and heavier grades. Therefore, the development of new sustainable energy technologies that meet environmental requirements and the demand for liquid fuels has become a driving force in addressing both the energy and environmental crises.

[0003] The Fischer-Tropsch synthesis reaction was discovered by German chemists Fischer and Tropsch in 1923. The reaction uses hydrogen and carbon monoxide as raw materials, producing hydrocarbons in the presence of a synthetic catalyst. The raw materials can be converted from coal, natural gas, coalbed methane, biomass, and other sources, and are widely available. The synthetic oil produced using Fischer-Tropsch synthesis technology differs significantly from conventional petroleum derivatives in terms of hydrocarbon composition and primary properties. It is primarily composed of paraffins and olefins, with a certain amount of oxygenates, with an olefin content exceeding 35%. It also has extremely low sulfur and nitrogen contents and is essentially free of cycloalkanes and aromatics. Therefore, the properties of Fischer-Tropsch synthetic oil can be exploited to remove the olefins and oxygenates through hydrogenation to produce specialty products such as light white oil and liquid wax. This offers significant advantages over producing light white oil and liquid wax from petroleum-based feedstocks.

[0004] US4500417A discloses a method for hydroconversion of Fischer-Tropsch oil, which requires presulfiding of the catalyst and injection of sulfur into the system to improve the activity and stability of the catalyst.

[0005] CN110016363B discloses a method and system for producing diesel and lubricant base oil from Fischer-Tropsch oil. The method comprises: pre-hydrogenating the Fischer-Tropsch oil fraction in the presence of hydrogen and a reduced pre-refining catalyst; then hydrorefining the product in the presence of hydrogen and a reduced hydrorefining catalyst, and separating the resulting product to obtain diesel-I, naphtha, and heavy oil; then hydroisomerizing the heavy oil in the presence of hydrogen and a hydroisomerizing catalyst; then hydrorefining the isomerized product to stabilize the product, and finally fractionating and separating the product to obtain diesel-II and lubricant base oil. This method enables the production of diesel from Fischer-Tropsch oil, as well as the direct production of lubricant base oil.

[0006] The Fischer-Tropsch synthesis oil has high olefin content, and a large amount of heat is released during hydrogenation. Therefore, during the Fischer-Tropsch synthesis oil hydrogenation process, there is a problem that the bed temperature is difficult to control due to the local reaction being too violent during the olefin hydrogenation saturation process, and the problem of carbon deposition and deactivation of the reduced catalyst and easy coking. SUMMARY

[0007] The present application is to solve the problem of easy coking of the reduced catalyst in the prior art Fischer-Tropsch synthesis oil hydrogenation process.

[0008] The present application provides a method for upgrading Fischer-Tropsch synthesis oil by hydrogenation, wherein the Fischer-Tropsch synthesis oil is mixed with hydrogen and then sequentially enters a hydrogenation protection reactor and a hydrofining reactor, and is contacted with a reduced hydrogenation protection catalyst and a reduced hydrofining catalyst to perform olefin saturation and hydrodeoxygenation reactions. The reaction effluent of the hydrofining reactor is separated to obtain at least a light white oil fraction, a liquid wax fraction, and a wax oil fraction. The packing volume ratio of the overall hydrogenation protection catalyst in the hydrogenation protection reactor to the overall hydrofining catalyst in the hydrofining reactor is 20-60:100. The temperature rise value of the hydrogenation protection reactor is controlled to be 30-75% of the total temperature rise value based on the total temperature rise of the hydrogenation protection reactor and the hydrofining reactor.

[0009] The Fischer-Tropsch synthesis oil described in the present application can be a synthetic light oil, a synthetic heavy oil, and a synthetic wax fraction obtained by a slurry bed Fischer-Tropsch synthesis process or a mixed fraction thereof, or can be a synthetic light oil, a synthetic heavy oil, and a synthetic wax fraction obtained by a fixed bed Fischer-Tropsch synthesis process or a mixed fraction thereof, or can be a mixed fraction of the Fischer-Tropsch synthesis oils obtained by the above-mentioned slurry bed process and fixed bed process.

[0010] In the present application, in order to solve the problem that the bed temperature is difficult to control due to the local reaction being too violent during the olefin hydrogenation saturation process, the present application preferably selects the catalyst packing scheme in the hydrogenation protection reactor and the hydrofining reactor, and the temperature rise control scheme. Further preferably, the packing volume ratio of the overall hydrogenation protection catalyst in the hydrogenation protection reactor to the overall hydrofining catalyst in the hydrofining reactor is 20-50:100. The temperature rise value of the hydrogenation protection reactor is controlled to be 30-60% of the total temperature rise value based on the total temperature rise of the hydrogenation protection reactor and the hydrofining reactor.

[0011] In an embodiment of the present application, the hydrogenation protection reactor is graded and packed with four or more hydrogenation protection catalysts, and the equivalent diameter of the hydrogenation protection catalysts decreases in turn along the direction of the reactant flow, and the activity increases in turn.

[0012] In one embodiment of the present invention, the hydroprotection reactor is graded and loaded with four hydroprotection catalysts, namely, hydroprotection catalyst I, hydroprotection catalyst II, hydroprotection catalyst III and hydroprotection catalyst IV, and the activity of the hydroprotection catalyst increases in the direction of the reactant flow;

[0013] In the hydrogenation protection reactor, based on the filling volume of hydrogenation protection catalyst IV, the filling volume of hydrogenation protection catalyst I is 10% to 30%, the filling volume of hydrogenation protection catalyst II is 60% to 80%, and the filling volume of hydrogenation protection catalyst III is 40% to 60%;

[0014] Preferably, the equivalent diameter of the hydrogenation protection catalyst I is 9 mm to 11 mm, and its composition, based on the weight of the hydrogenation protection catalyst I, is 0.3% to 0.5% nickel oxide, 0.1% to 0.3% molybdenum oxide, and the balance is aluminum oxide;

[0015] The equivalent diameter of the hydrogenation protection catalyst II is 5.6 mm to 6.5 mm. Based on the weight of the hydrogenation protection catalyst II, its composition is 1.0% to 3.0% nickel oxide, 0.2% to 0.5% molybdenum oxide, and the balance is aluminum oxide.

[0016] The equivalent diameter of the hydrogenation protection catalyst III is 2.5 mm to 3.5 mm. Based on the weight of the hydrogenation protection catalyst III, its composition is 2.0% to 4.0% nickel oxide, 0.4% to 0.8% molybdenum oxide, and the balance is aluminum oxide.

[0017] The equivalent diameter of the hydrogenation protection catalyst IV is 1.5 mm to 2.5 mm. Based on the weight of the hydrogenation protection catalyst IV, its composition is 4.0% to 8.0% nickel oxide, 1.0% to 3.0% molybdenum oxide, and the balance is aluminum oxide.

[0018] In one embodiment of the present invention, the hydrorefining catalyst is a supported catalyst, the carrier is alumina, the content of nickel oxide is 6.0 to 16.0% by weight, based on the hydrorefining catalyst, the content of the oxide of the auxiliary element is 1.0 to 5.0% by weight, and the auxiliary element is selected from one or more of Mg, Li, Co, Fe, Mo and W; the equivalent diameter of the hydrorefining catalyst is 1.3 mm to 1.8 mm.

[0019] In one embodiment of the present invention, the hydrorefining reactor is provided with 3 to 5 catalyst beds, and the hydrorefining catalysts loaded in different beds are the same hydrorefining catalyst or different hydrorefining catalysts.

[0020] In one embodiment of the present invention, the hydrotreating reactor is provided with three catalyst beds. Based on the catalyst loading volume of the third bed, the catalyst loading volume of the first bed is 50-70%, and the catalyst loading volume of the second bed is 70-90%.

[0021] The present invention does not impose any restrictions on the preparation process of the hydrogenation protection catalyst and the hydrorefining catalyst.

[0022] In one embodiment of the present invention, the hydrotreating catalyst of the present invention can be obtained by the following preparation method:

[0023] The alumina shaped carrier is prepared by forming, drying, and hydrothermal stability treatment steps of an alumina precursor. The alumina can also be an industrial carrier. The forming can be carried out according to conventional methods, such as tableting, ball rolling, extrusion, etc. The drying step is to maintain the temperature at 100-160°C for 4-8 hours. The roasting step is to roast the dried strips at 500-800°C under air conditions for 3-8 hours, preferably the roasting temperature is 550-750°C and the roasting time is 3-6 hours. The hydrothermal stability treatment can be water vapor modification, that is, introducing water vapor into the air.

[0024] The auxiliary element is selected from one or more of Mg, Li, Co, Fe, Mo, and W. The auxiliary element is introduced by saturating the carrier with an aqueous solution containing the auxiliary element compound, followed by drying and calcination. The drying temperature is 100-180°C, the drying time is 1-20 hours, and the calcination temperature is 300-750°C, and the calcination time is 1-18 hours.

[0025] The nickel is introduced by non-saturated impregnation of an alumina support with an aqueous solution containing a nickel compound, followed by drying and optionally calcining. The drying and calcining conditions are conventional, for example, a drying temperature of 100 to 300°C, preferably 100 to 280°C, a drying time of 1 to 12 hours, preferably 2 to 8 hours; a calcination temperature of 300 to 550°C, preferably 300 to 400°C, and a calcination time of 1 to 10 hours, preferably 2 to 8 hours.

[0026] The non-saturated impregnation method refers to a method in which the ratio of the volume VL of the impregnation liquid during non-saturated impregnation to the volume Vc of the impregnation liquid during saturated impregnation satisfies the following conditions: VL / Vc=0.75-0.95, preferably VL / Vc=0.80-0.90.

[0027] In the present invention, the hydroprotection catalyst and the hydrorefining catalyst are both reduced catalysts during normal use.

[0028] In one embodiment of the present invention, the hydrogenation protection catalyst is reduced and activated in the presence of hydrogen before use to obtain the reduced hydrogenation protection catalyst. The hydrorefining catalyst is reduced and activated in the presence of hydrogen before use to obtain the reduced hydrorefining catalyst.

[0029] In a preferred embodiment of the present invention, the reduction activation of the hydrogenation protection catalyst and the hydrorefining catalyst adopts a two-step activation process, the first step of the reduction activation temperature is 340-380 ° C, the activation time is 12-20 hours, and the second step of the reduction activation temperature is 390-420 ° C, the activation time is 4-12 hours;

[0030] More preferably, the first step reduction activation temperature is 350-370° C. and the activation time is 12-18 h, and the second step reduction activation temperature is 390-410° C. and the activation time is 6-12 h.

[0031] The two-step activation process can enhance the olefin hydrogenation saturation and hydrodeoxygenation activities of the hydrotreating catalyst, thereby further improving product quality.

[0032] In one embodiment of the present invention, the reaction conditions of the hydrogenation protection reactor are: hydrogen partial pressure 2.0-10.0 MPa, reaction temperature 150-280°C, hydrogen-to-oil volume ratio 100-500, volume space velocity 3.0-15.0 h -1 ;

[0033] The reaction conditions of the hydrotreating reactor are: hydrogen partial pressure of 2.0-10.0 MPa, reaction temperature of 280-380°C, hydrogen-oil volume ratio of 100-500, volume space velocity of 2.0-5.0 h -1 .

[0034] In one embodiment of the present invention, the reaction effluent from the hydrotreating reactor is subjected to gas-liquid separation in multiple gas-liquid separators to produce a hydrogenated oil. The multiple gas-liquid separators may be a combination of a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator, and a cold low-pressure separator. The resulting hydrogenated oil is then fed into a fractionation system to produce a naphtha fraction, a light white oil fraction, a liquid wax fraction, and a wax oil fraction.

[0035] The density of the light white oil fraction is 0.74-0.75 g / cm 3 , aromatic hydrocarbon content 0.003 to 0.009 weight %; density of the liquid wax fraction 0.77 to 0.78 g / cm 3 , normal alkane content 92 to 95 weight%.

[0036] In view of the sulfur-free characteristic of Fischer-Tropsch synthetic oil, the present invention adopts a reduced hydrogenation protection catalyst and a reduced hydrogenation refining catalyst, which can reduce the catalyst pre-sulfurization operation and the sulfur injection operation to maintain the stable activity of the sulfurized catalyst. This not only reduces the operating cost, but also improves the problem of high sulfur content in the low-gas fraction of the hydrogenation unit, thereby reducing environmental protection costs.

[0037] In addition, the present invention effectively controls the reasonable distribution of temperature rise in the hydroprotection reactor and the hydrorefining reactor by optimizing the catalyst loading ratio and grading scheme of the hydroprotection reactor and the hydrorefining reactor, avoids violent local reactions and reduces the risk of carbon deposition and coking of the reduced catalyst, thereby effectively improving the stable operation cycle of the reduced catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of one embodiment of the method for hydrogenating and upgrading Fischer-Tropsch synthetic oil provided by the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited thereto.

[0040] Figure 1 FIG. 1 is a schematic diagram of one embodiment of the method for hydrogenating and upgrading Fischer-Tropsch synthetic oil provided by the present invention. Figure 1 As shown, the Fischer-Tropsch synthetic oil 1 enters the hydroprotection reactor 2 and the hydrofining reactor 3 in sequence for reaction, the logistics coming out of the hydrofining reactor 3 enters the hot high fraction 4 for gas-liquid separation, the liquid phase coming out of the hot high fraction 4 enters the hot low fraction 6, the gas phase of the hot high fraction 4 enters the cold high fraction 5 and is further separated into gas phase, liquid hydrocarbons and water 8, the gas phase separated from the cold high fraction 5 is hydrogen-rich gas, which is pressurized by the circulating compressor 16 and mixed with new hydrogen 17 and returned to the reactor inlet and between the bed layer, the liquid hydrocarbons separated from the cold high fraction 5 enter the cold low fraction 7 together with the gas phase of the hot low fraction 6 for further gas-liquid separation, the liquid phase 9 separated from the cold low fraction 7 and the liquid phase 10 of the hot low fraction 6 enter the distillation tower 11 together, and are separated into the naphtha fraction 12, the light white oil fraction 13, the liquid wax fraction 14 and the bottom wax oil fraction 19 of the hydrofining unit. Among them, the naphtha fraction 12, the light white oil fraction 13, and the liquid wax fraction 14 can be used as products to exit the device, and the bottom wax oil fraction 19 can be used as a raw material for a downstream cracking unit for further reaction.

[0041] The present invention will be further described below with reference to the examples, but the present invention is not limited thereto.

[0042] In the examples and comparative examples, a full fraction of Fischer-Tropsch synthetic oil was used as a raw material, and its properties are shown in Table 1.

[0043] The hydrogenation protection catalyst I used has an equivalent diameter of 10 mm and a composition of 0.4% nickel oxide, 0.2% molybdenum oxide, and the balance aluminum oxide, based on the weight of the hydrogenation protection catalyst I.

[0044] Hydrogenation protected catalyst II, with an equivalent diameter of 6 mm, and a composition based on the weight of hydrogenation protected catalyst II of 2.0% nickel oxide, 0.4% molybdenum oxide, and the balance aluminum oxide;

[0045] Hydrogenation protected catalyst III, with an equivalent diameter of 3 mm and a composition of 3.0% nickel oxide, 0.6% molybdenum oxide, and the balance aluminum oxide, based on the weight of hydrogenation protected catalyst III;

[0046] The hydrogenation protected catalyst IV has an equivalent diameter of 2 mm and a composition of 6.0% nickel oxide, 2.0% molybdenum oxide, and the balance aluminum oxide, based on the weight of the hydrogenation protected catalyst IV.

[0047] The hydrorefining catalyst used has an equivalent diameter of 1.5 mm. Based on the weight of the hydrorefining catalyst, the nickel oxide content is 12%, the molybdenum oxide content is 3%, and the balance is aluminum oxide.

[0048] Example 1

[0049] The Fischer-Tropsch synthetic oil enters the hydroprotection reactor and the hydrotreating reactor in sequence, contacts and reacts with the hydroprotection catalyst and the hydrotreating catalyst to carry out olefin saturation and hydrodeoxygenation reactions. The reaction effluent from the hydrotreating reactor enters the gas-liquid separation system for gas-liquid separation to obtain the hydrogenated oil which enters the fractionation system to separate the naphtha fraction, light white oil fraction, liquid wax fraction and bottom wax oil fraction.

[0050] The volume ratio of the hydroprotection catalyst to the hydrorefining catalyst is 50:100.

[0051] In the hydrogenation protection reactor, based on the filling volume of hydrogenation protection catalyst IV, the filling volume of hydrogenation protection catalyst I in the hydrogenation protection reactor is 20%, the filling volume of hydrogenation protection catalyst II is 70%, and the filling volume of hydrogenation protection catalyst III is 50%.

[0052] The hydrotreating reactor is equipped with three catalyst beds. Based on the catalyst loading volume of the third bed, the catalyst loading volume of the first bed is 60%, and the catalyst loading volume of the second bed is 80%. The hydrotreating catalyst loaded in the three beds is the same catalyst.

[0053] Before use, the hydroprotected catalyst and hydrorefining catalyst were reduced and activated in the presence of hydrogen to obtain the reduced hydroprotected catalyst and reduced hydrorefining catalyst, respectively. The reduction and activation process was performed in a step-by-step manner: the first step was at a temperature of 360°C for 18 hours; the second step was at a temperature of 400°C for 6 hours. Specific operating conditions, reaction performance, and product properties are shown in Tables 2 and 3.

[0054] As can be seen from Table 3, based on the Fischer-Tropsch oil feedstock, the calculated olefin saturation rate of the hydrogenated oil is 98.5% and the deoxygenation rate is 98.6%, meeting the requirements for Fischer-Tropsch oil hydrorefining. The light white oil fraction produced has an aromatics content of 0.005% by weight, suitable for use as a high-quality light white oil product; the liquid wax fraction has a normal paraffin content of 93.8% by weight, suitable for use as a high-quality liquid wax product. In terms of reaction performance, due to the reasonable gradation of the catalysts in the hydrotreating guard reactor and the hydrorefining reactor, the temperature rise of the guard reactor and the refining reactor is 24°C and 33°C, respectively. This ensures that the reaction heat is rationally distributed between the two reactors, reduces the risk of coking and carbon deposition on the hydrorefining catalyst, and facilitates the long-term stable operation of the unit.

[0055] Example 2

[0056] The Fischer-Tropsch synthetic oil enters the hydroprotection reactor and the hydrotreating reactor in sequence, contacts and reacts with the hydroprotection catalyst and the hydrotreating catalyst to carry out olefin saturation and hydrodeoxygenation reactions. The reaction effluent from the hydrotreating reactor enters the gas-liquid separation system for gas-liquid separation to obtain the hydrogenated oil which enters the fractionation system to separate the naphtha fraction, light white oil fraction, liquid wax fraction and bottom wax oil fraction.

[0057] The volume ratio of the hydroprotection catalyst to the hydrorefining catalyst is 25:100.

[0058] In the hydrogenation protection reactor, based on the protection catalyst IV, the filling volume of the protection catalyst I in the protection reactor is 10%, the filling volume of the protection catalyst II is 60%, and the filling volume of the protection catalyst III is 40%.

[0059] The hydrotreating reactor is equipped with three catalyst beds. Based on the catalyst loading volume of the third bed, the catalyst loading volume of the first bed is 50%, and the catalyst loading volume of the second bed is 70%. The hydrotreating catalyst loaded in the three beds is the same catalyst.

[0060] Before use, the hydroprotected catalyst and hydrorefining catalyst were reduced and activated in the presence of hydrogen to obtain the reduced hydroprotected catalyst and reduced hydrorefining catalyst, respectively. The reduction and activation process was performed in a stepwise manner: the first step was at 350°C for 12 hours; the second step was at 410°C for 12 hours. Specific operating conditions, reaction performance, and product properties are shown in Tables 2 and 3.

[0061] As can be seen from Table 3, based on the Fischer-Tropsch oil feedstock, the calculated olefin saturation rate of the hydrogenated oil is 97.0% and the deoxygenation rate is 96.2%, meeting the requirements for Fischer-Tropsch oil hydrotreating. The aromatics content of the light white oil fraction produced is 0.009% by weight, which can be used as a high-quality light white oil product; the normal paraffin content of the liquid wax fraction is 92.1% by weight, which can be used as a high-quality liquid wax product. In terms of reaction performance, due to the reasonable gradation of the catalysts in the hydrotreating guard reactor and the hydrotreating reactor, the temperature rise of the hydrotreating guard reactor and the hydrotreating reactor is 20°C and 38°C, respectively. This ensures that the reaction heat is reasonably distributed between the two reactors, reduces the risk of coking and carbon deposition on the hydrotreating catalyst, and facilitates the long-term stable operation of the unit.

[0062] Example 3

[0063] The Fischer-Tropsch synthetic oil enters the hydroprotection reactor and the hydrotreating reactor in sequence, contacts and reacts with the hydroprotection catalyst and the hydrotreating catalyst to carry out olefin saturation and hydrodeoxygenation reactions. The reaction effluent from the hydrotreating reactor enters the gas-liquid separation system for gas-liquid separation to obtain the hydrogenated oil which enters the fractionation system to separate the naphtha fraction, light white oil fraction, liquid wax fraction and bottom wax oil fraction.

[0064] The volume ratio of the hydroprotection catalyst to the hydrorefining catalyst is 40:100.

[0065] In the hydrogenation protection reactor, based on the protection catalyst IV, the filling volume of the protection catalyst I in the protection reactor is 30%, the filling volume of the protection catalyst II is 80%, and the filling volume of the protection catalyst III is 60%.

[0066] The hydrotreating reactor is equipped with three catalyst beds. Based on the catalyst loading volume of the third bed, the catalyst loading volume of the first bed is 70%, and the catalyst loading volume of the second bed is 90%. The hydrotreating catalyst loaded in the three beds is the same catalyst.

[0067] Before use, the hydroprotected catalyst and hydrorefining catalyst were reduced and activated in the presence of hydrogen to obtain the reduced hydroprotected catalyst and reduced hydrorefining catalyst, respectively. The reduction and activation process was performed in a step-by-step manner: the first step was at 370°C for 16 hours; the second step was at 390°C for 8 hours. Specific operating conditions, reaction performance, and product properties are shown in Tables 2 and 3.

[0068] As can be seen from Table 3, based on the Fischer-Tropsch oil feedstock, the calculated olefin saturation rate of the hydrogenated oil is 98.1% and the deoxygenation rate is 98.2%, meeting the requirements for Fischer-Tropsch oil hydrotreating. The light white oil fraction produced has an aromatics content of 0.003% by weight, suitable for use as a high-quality light white oil product; the liquid wax fraction has a normal paraffin content of 94.2% by weight, suitable for use as a high-quality liquid wax product. In terms of reaction performance, due to the reasonable grading of the catalysts in the hydroprotection reactor and the hydrorefining reactor, the temperature rises of the hydroprotection reactor and the hydrorefining reactor were 28°C and 37°C, respectively. This ensures that the reaction heat is properly distributed between the two reactors, reduces the risk of coking and carbon deposition on the hydrorefining catalyst, and facilitates the long-term stable operation of the unit.

[0069] Comparative Example 1

[0070] This comparative example employed the same distillation process as Example 1. The difference from Example 1 was that the reduction activation process for the hydroprotected catalyst and the hydrorefining catalyst employed a one-step reduction process. During the reduction activation, the temperature was directly raised from 30°C to 360°C, eliminating the step of constant temperature activation at 400°C for 6 hours. The total reduction activation time at 360°C was the same as in Example 1, at 24 hours. Specific operating conditions, reaction performance, and product properties are shown in Tables 2 and 3.

[0071] As can be seen from Table 3, Comparative Example 1, using a one-step reduction process, achieved a hydrorefining oil with an olefin saturation rate of 94.8% and a hydrodeoxygenation rate of 95.1% based on the Fischer-Tropsch oil feedstock. The hydrorefining results for the Fischer-Tropsch oil were inferior to those of Example 1. The aromatics content of the produced light white oil fraction was 0.01% by weight, which was higher than that of Example 1. The normal paraffin content of the liquid wax fraction was 91.3% by weight, which did not meet the GB / T 32066-2015 requirement of a normal paraffin content of not less than 92% for high-quality liquid wax.

[0072] Comparative Example 2

[0073] This comparative example employed the same distillation process as Example 1. The difference from Example 1 was that the reduction activation process employed a one-step reduction process. During the reduction activation, the temperature was directly raised from 30°C to 400°C, eliminating the 18-hour activation step at 360°C. The total reduction activation time at 400°C was the same as in Example 1, at 24 hours. Specific operating conditions, reaction performance, and product properties are shown in Tables 2 and 3.

[0074] As can be seen from Table 3, in Comparative Example 2, which employed a one-step reduction process, the olefin saturation rate of the hydrogenated oil produced was only 90.1%, and the hydrodeoxygenation rate was only 80.3%, based on the Fischer-Tropsch oil feedstock. The hydrorefining effect of the Fischer-Tropsch oil was inferior to that of Example 1. The aromatics content of the produced light white oil fraction was 0.052% by weight, failing to meet the SH / T 0913-2015 requirement for high-quality light white oil (II) of less than 0.01% by weight of aromatics. The normal paraffin content of the liquid wax fraction was 89.6% by weight, failing to meet the requirement for a high-quality liquid wax normal paraffin content of greater than 92% by weight.

[0075] Comparative Example 3

[0076] The difference between this comparative example and Example 1 is that the volume ratio of the hydrogenation protection catalyst to the hydrorefining catalyst in Comparative Example 3 is 13.3: 100. Specific operating conditions, reaction performance, and product properties are shown in Tables 2 and 3.

[0077] As can be seen from Table 3, the temperature rises of the hydroprotection reactor and the hydrofining reactor in Comparative Example 3 are 7°C and 53°C, respectively. The reaction exotherm is too concentrated in the hydrofining reactor, and the reaction heat cannot be reasonably distributed in the two reactors, resulting in increased coking and carbon deposition of the hydrofining catalyst, which is not conducive to the long-term stable operation of the device.

[0078] Table 1 Properties of crude oil

[0079] Fischer-Tropsch synthetic oil raw materials <![CDATA[密度(20℃) / (g / cm 3 )]]> 0.8001 Oxygen content / weight% 1.13 C content / weight% 85.16 H content / weight% 14.84 Olefin content / weight% 23.17 Aromatic content / weight% 0.14 Distillation range ASTM D-1160 / ℃ IBP 78 50％ 376 95％ 653 Metal content / (μg / g) Fe 5.1 Cu 0.6 Mg 0.5 Na 1.2 Ca 0.6 Al 0.5

[0080] Table 2 Operating conditions

[0081]

[0082]

[0083] Table 3 Reaction performance evaluation results and product properties

[0084]

[0085]

Claims

1. A method for hydrogenating and upgrading Fischer-Tropsch oil, characterized in that: The Fischer-Tropsch synthetic oil is mixed with hydrogen and sequentially enters a hydroprotection reactor and a hydrorefining reactor, where it contacts a reduced hydroprotection catalyst and a reduced hydrorefining catalyst to carry out olefin saturation and hydrodeoxygenation reactions. The reaction effluent of the hydrorefining reactor is separated to obtain at least a light white oil fraction, a liquid wax fraction, and a wax oil fraction. The filling volume ratio of the overall hydroprotection catalyst in the hydroprotection reactor to the overall hydrorefining catalyst in the hydrorefining reactor is 20 to 60:

100. Based on the total temperature rise of the hydroprotection reactor and the hydrorefining reactor, the temperature rise of the hydroprotection reactor is controlled to be 30 to 75% of the total temperature rise. The hydrogenation protection reactor is graded and loaded with four hydrogenation protection catalysts, namely hydrogenation protection catalyst I, hydrogenation protection catalyst II, hydrogenation protection catalyst III and hydrogenation protection catalyst IV, and the activity of the hydrogenation protection catalyst increases in the direction of the reactant flow; In the hydrogenation protection reactor, based on the filling volume of hydrogenation protection catalyst IV, the filling volume of hydrogenation protection catalyst I is 10% to 30%, the filling volume of hydrogenation protection catalyst II is 60% to 80%, and the filling volume of hydrogenation protection catalyst III is 40% to 60%; The equivalent diameter of the hydrogenation protection catalyst I is 9 mm to 11 mm. Based on the weight of the hydrogenation protection catalyst I, its composition is 0.3% to 0.5% nickel oxide, 0.1% to 0.3% molybdenum oxide, and the balance is aluminum oxide; The equivalent diameter of the hydrogenation protection catalyst II is 5.6 mm to 6.5 mm. Based on the weight of the hydrogenation protection catalyst II, its composition is 1.0% to 3.0% nickel oxide, 0.2% to 0.5% molybdenum oxide, and the balance is aluminum oxide. The equivalent diameter of the hydrogenation protection catalyst III is 2.5 mm to 3.5 mm. Based on the weight of the hydrogenation protection catalyst III, its composition is 2.0% to 4.0% nickel oxide, 0.4% to 0.8% molybdenum oxide, and the balance is aluminum oxide. The equivalent diameter of the hydrogenation protection catalyst IV is 1.5 mm to 2.5 mm. Based on the weight of the hydrogenation protection catalyst IV, its composition is 4.0% to 8.0% nickel oxide, 1.0% to 3.0% molybdenum oxide, and the balance is aluminum oxide.

2. The method according to claim 1, characterized in that The loading volume ratio of the integral hydroprotectant catalyst in the hydroprotection reactor to the integral hydrorefining catalyst in the hydrorefining reactor is 20 to 50:100; Taking the total temperature rise of the hydrogenation protection reactor and the hydrotreating reactor as a benchmark, the temperature rise value of the hydrogenation protection reactor is controlled to be 30-60% of the total temperature rise value.

3. The method according to claim 1, characterized in that The hydrorefining catalyst is a supported catalyst, the carrier is alumina, and based on the hydrorefining catalyst, the content of nickel oxide is 6.0 to 16.0% by weight, the content of the oxide of the auxiliary element is 1.0 to 5.0% by weight, and the auxiliary element is selected from one or more of Mg, Li, Co, Fe, Mo and W; the equivalent diameter of the hydrorefining catalyst is 1.3 mm to 1.8 mm.

4. The method according to claim 1, wherein The hydrorefining reactor is provided with 3 to 5 catalyst beds, and the hydrorefining catalysts loaded in different beds are the same hydrorefining catalyst or different hydrorefining catalysts.

5. The method according to claim 4, characterized in that The hydrofining reactor is provided with three catalyst beds. Taking the catalyst filling volume of the third bed as a basis, the catalyst filling volume of the first bed is 50-70%, and the catalyst filling volume of the second bed is 70-90%.

6. The method according to claim 1, characterized in that Before use, the hydrogenation protection catalyst is reduced and activated in the presence of hydrogen to obtain the reduced hydrogenation protection catalyst. Before use, the hydrorefining catalyst is reduced and activated in the presence of hydrogen to obtain the reduced hydrorefining catalyst. The reduction activation of the hydrogenation protection catalyst and the hydrorefining catalyst adopts a two-step activation process. The first step is a reduction activation temperature of 340-380°C and an activation time of 12-20 hours. The second step is a reduction activation temperature of 390-420°C and an activation time of 4-12 hours.

7. The method according to claim 6, characterized in that The reduction activation of the hydrogenation protection catalyst and the hydrorefining catalyst adopts a two-step activation process. The first step is a reduction activation temperature of 350-370°C and an activation time of 12-18 hours. The second step is a reduction activation temperature of 390-410°C and an activation time of 6-12 hours.

8. The method according to claim 1, characterized in that The reaction conditions of the hydrogenation protection reactor are: hydrogen partial pressure 2.0-10.0 MPa, reaction temperature 150-280°C, hydrogen-to-oil volume ratio 100-500, volume space velocity 3.0-15.0 h -1 ; The reaction conditions of the hydrotreating reactor are: hydrogen partial pressure of 2.0-10.0 MPa, reaction temperature of 280-380°C, hydrogen-oil volume ratio of 100-500, volume space velocity of 2.0-5.0 h -1 .

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