Method for pretreating Fischer-Tropsch synthesis catalyst

Abstract

The invention provides a method for pretreating a Fischer-Tropsch synthesis catalyst and a method for converting Fischer-Tropsch synthesis gas by using the pretreated catalyst obtained by the method for pretreating the Fischer-Tropsch synthesis catalyst. The method for pretreating the Fischer-Tropsch synthesis catalyst comprises the following steps: 1) reducing a main catalyst which is an iron-based catalyst; 2) carbonizing the main catalyst; (3) passivating the main catalyst; and 4) impregnating a mixture of an auxiliary agent and the main catalyst obtained in the step 3) with liquid wax, naphtha or heavy diesel oil. In the method for pretreating the Fischer-Tropsch synthesis catalyst, a passivation process is introduced after reduction and carbonization, the activity of the catalyst is stably and slowly released, and rapid deactivation is avoided; after the main catalyst is reduced, carbonized and passivated, the auxiliary agent is added and mixed, so that the auxiliary agent does not participate in the reduction and carbonization process of the iron oxide and does not influence the reduction and carbonization effect; the liquid wax or naphtha or heavy diesel oil is mixed with the mixture slurry of the main catalyst and the auxiliary agent, so that transportation and pipeline transportation are facilitated.

Description

Technical Field

[0001] The present invention relates to the field of conversion of synthesis gas into higher hydrocarbons, and in particular to a method for pretreating a Fischer-Tropsch synthesis catalyst, a pretreated Fischer-Tropsch synthesis catalyst obtained by the method, and a method for converting synthesis gas using the pretreated Fischer-Tropsch synthesis catalyst. Background Art

[0002] Synthesis gas (H 2 +CO) is the most common raw gas in the coal chemical industry. Many products can be obtained through different reaction pathways. The most common method is to use Fischer-Tropsch synthesis to obtain fuels and chemicals such as gasoline, diesel, wax and alpha olefins. Fischer-Tropsch synthesis reactions can be divided into low-temperature Fischer-Tropsch (220-270°C) and high-temperature Fischer-Tropsch (320-350°C) according to the reaction temperature. Low-temperature Fischer-Tropsch generally uses precipitated iron catalysts, and the reactor can be a fixed bed or a slurry bed. The products are mainly diesel and wax. High-temperature Fischer-Tropsch synthesis often uses molten iron catalysts, and the products are mainly gasoline and alpha olefins. The reactor generally uses a fluidized bed.

[0003] CN202211662125.1 discloses a fluidized bed catalyst composition, a preparation method and an application thereof, which provides a catalyst composition for producing chlorine by oxidation of hydrogen chloride in a fluidized bed reactor and a preparation method thereof, comprising catalyst A and catalyst B, respectively comprising a carrier and an active component, both comprising alkali metal elements and rare earth elements, being able to tolerate a high concentration of fluorine-containing compounds, and maintaining stable performance during long-term use, and having industrial application value. A is the main catalytically active component, used to catalyze the reaction of chlorine production by oxidation of hydrogen chloride, and catalyst B is a secondary catalytically active component, serving as the main component for adsorbing fluorine-containing compounds.

[0004] CN201610728588.1 discloses a method for improving the reaction performance of preparing high-carbon alcohols (C6+ alcohols) from synthesis gas in one step, which relates to a bifunctional catalyst combination system, including catalysts A and B, A is a polymer-supported Cu-Fe-Co-based catalyst, and B is a supported Cu-Zn-Fe-based catalyst. The above bifunctional catalyst combination can be loaded in a multi-layer manner along the material flow direction in a fixed bed reactor, and is used for preparing high-carbon alcohols from synthesis gas in one step, and reduction activation treatment is performed before the reaction.

[0005] CN201810643929.4 discloses a method for pretreatment of activation of a Fischer-Tropsch iron catalyst in a fixed bed reactor, which provides a method for pretreatment of activation of a Fischer-Tropsch iron catalyst in a fixed bed reactor. The air velocity and atmosphere are adjusted under different temperature conditions, and the volume concentration of CO in the tail gas is used as an indicator to characterize whether the reduction is completed. At the same time, the reactor is divided into multiple sections along the flow direction of the synthesis gas, and different amounts of catalysts are loaded respectively.

[0006] CN201410720252.1 discloses a device and method for continuously reducing a catalyst, which provides a device for continuously reducing a catalyst in a rotary reactor. The advantages are simple operation and the ability to avoid wear during the reduction process.

[0007] Whether it is a traditional integrated catalyst or a bifunctional catalyst, the design idea is to combine additives, active components and carriers together. For example, in CN202211662125.1, catalysts A and B both contain active components (copper, alkali metals and rare earth elements), but the composition is slightly different. The two catalysts in CN201610728588.1 are Cu-Fe-Co-based and Cu-Zn-Fe-based catalysts. The components of this type of catalyst may undergo unpredictable and uncontrollable changes during the reduction or reaction process, causing their performance to deviate from the design value. For example, during the reduction process of the iron catalyst, the additive interacts with the carrier or active component, which may affect the final reduction effect; the K component is gradually lost during the reaction. This process is inevitable and the loss ratio is difficult to estimate. The above changes may have a negative impact on the performance of the catalyst.

[0008] In addition, the proportion and loading form of bifunctional catalysts are relatively fixed. After entering the reactor, if it is found that the actual reaction performance is different from the target value, or if the reaction performance needs to be temporarily changed, it will be difficult to adjust. In most cases, the only option is to change the operating conditions or reload the catalyst.

[0009] The gain effect after mixing the two catalysts involved in CN202211662125.1 is limited to a higher conversion rate after long-term operation, and does not involve regulating product distribution and selectivity.

[0010] The active component of the iron-based catalyst for Fischer-Tropsch synthesis is an iron-carbon compound (pre-treated iron oxide), the carrier is generally silicon oxide or aluminum oxide, and there are also some auxiliary components. This type of catalyst has the following technical problems during use:

[0011] 1. Certain additives (such as K and Mn) do not promote the reduction reaction, but affect the composition of the active phase after pretreatment. However, if the catalyst does not contain these additives, the performance will be poor.

[0012] 2. The additives are lost due to dissolution and carrying. For example, the additive K of the iron catalyst is easily dissolved in synthetic water and lost.

[0013] 3. After reduction or during the reaction, some components of the catalyst undergo unpredictable and uncontrollable changes, resulting in deviations from the designed values. For example, the optimal K / Fe ratio in the precipitated iron catalyst is 4%. The K / Fe ratio of the catalyst will change after pretreatment and during the reaction, and will generally be lower than the target value or the optimized value, and the degree of deviation is difficult to predict during the reaction. The K / Fe ratio has a great influence on the activity, selectivity and stability of the catalyst [Liu Fuxia et al., Journal of Catalysis, 2004, 25(11):878-886].

[0014] 4. Traditional synthesis gas conversion catalysts are shipped in an oxidized state, such as Fischer-Tropsch synthesis iron catalysts shipped in iron oxide and cobalt catalysts shipped in cobalt oxide. They need to be pretreated to a reduced state before use. The performance of the catalyst during use is directly related to the pretreatment process, so pretreatment is a very important process before the catalyst is used.

[0015] The pretreatment of oxidized catalysts is crucial to the performance of the catalyst. When the main catalyst does not contain a promoter, unlike traditional integrated catalysts and bifunctional catalysts, a pretreatment method for the main catalyst without a promoter is urgently needed.

[0016] The differences between the present invention and the prior art, namely the innovative points are as follows:

[0017] 1. The catalyst system is divided into two parts: the main catalyst and the auxiliary agent. The main catalyst is the main active component (such as metal oxide) and the carrier (such as silicon oxide, aluminum oxide, carbon material, molecular sieve, etc.), and its function is to achieve high activity of the catalytic reaction; the auxiliary agent is a combination of multiple auxiliary agents, including a mixture of alkali metals, rare earth metals, manganese, zinc and boron, and the proportion of each component is not fixed. Its function is to flexibly adjust the product distribution and ensure the stability of the overall catalytic performance.

[0018] 2. The main catalyst is not easy to wear and lose, while the auxiliary agent is relatively easy to wear and lose. During the reaction process, the traditional integrated catalyst (active component + carrier + auxiliary agent) needs to frequently add auxiliary agents to ensure the reaction performance. The commonly used method is to unload some of the integrated catalysts that have been used for a long time (auxiliary agent loss), and then add new integrated catalysts to ensure the overall stability of the reactor. If the combination of the main catalyst and auxiliary agent involved in the present invention is adopted, when the original auxiliary agent in the reactor is lost and causes the catalyst performance to change, it is only necessary to add the auxiliary agent to ensure the overall stability of the reactor. Obviously, the present invention consumes less catalyst and has lower cost.

[0019] 3. The pretreatment process is as follows: (1) The main catalyst is first reduced with hydrogen in a fluidized bed. (2) The main catalyst is further carbonized with synthesis gas in a fluidized bed; (3) The main catalyst is passivated with a passivation gas in a fluidized bed; (4) The main catalyst and the auxiliary agent are impregnated and mixed with liquid wax, naphtha or heavy diesel in a stirred tank reactor.

[0020] During the reaction, the composition and proportion of the added additives are adjusted according to the gap between the reaction performance and product distribution and the target to ensure the stability of the catalyst performance. Summary of the invention

[0021] In view of the problems existing in the prior art, the present invention aims to provide a method for pretreating a Fischer-Tropsch synthesis catalyst, and a method for converting synthesis gas using the Fischer-Tropsch synthesis catalyst pretreated by the method.

[0022] According to a first aspect of the present invention, there is provided a method for pretreating a Fischer-Tropsch synthesis catalyst, comprising the following steps:

[0023] 1) Reduction of a main catalyst, wherein the main catalyst is an iron-based catalyst;

[0024] 2) Carbonization of the main catalyst;

[0025] 3) deactivation of the primary catalyst; and

[0026] 4) impregnating a mixture of the auxiliary agent and the main catalyst obtained in step 3) with liquid wax, naphtha or heavy diesel oil.

[0027] Preferably, the iron-based catalyst comprises iron oxide, Cu and its oxide and a carrier, wherein the mass ratio of Fe:carrier:Cu=100:15-45:0.1-4.5.

[0028] Preferably, the carrier is selected from SiO 2 、Al 2 O 3 , carbon materials and molecular sieves, etc.

[0029] Preferably, the reduction of the main catalyst comprises the following steps:

[0030] The iron-based catalyst is reduced in a reactor under the following conditions,

[0031] 1-1) The first stage: the starting temperature reaches 180°C,

[0032] Heating rate: 20-80°C / h, preferably 30-60°C / h,

[0033] Pure N 2 atmosphere,

[0034] Air velocity 1~15L / g / h,

[0035] Pressure 0.01-0.3 MPa, preferably 0.05-0.25 MPa;

[0036] 1-2) Second stage: 180℃ to 280℃,

[0037] Heating rate 10-35°C / h, preferably 15-25°C / h,

[0038] (40vol%~60vol%)N 2 -(40vol%~60vol%)H 2 atmosphere,

[0039] Air velocity 2~14L / g / h,

[0040] Pressure 0.2-2.0 MPa, preferably 0.4-1.5 MPa;

[0041] 1-3) The third stage: 280°C to the final reduction temperature of 300-400°C, preferably 320-360°C,

[0042] Heating rate 6-18°C / h, preferably 8-15°C / h,

[0043] (5vol%~20vol%)N 2 -(80vol%~95vol%)H 2 atmosphere,

[0044] Air velocity 2~14L / g / h,

[0045] Pressure 1.0-3.5 MPa, preferably 1.5-2.5 MPa;

[0046] 1-4) The fourth stage: the final reduction temperature is maintained for 2 to 16 hours, preferably 6 to 12 hours,

[0047] (5vol%~20vol%)N 2 -(80vol%~95vol%)H 2 atmosphere,

[0048] Air velocity 2~14L / g / h,

[0049] The pressure is 1.0 to 3.5 MPa, preferably 1.5 to 2.5 MPa.

[0050] Preferably, the carbonization of the main catalyst comprises the following steps:

[0051] The iron-based catalyst is carbonized in a reactor under the following conditions:

[0052] The temperature is reduced from the final reduction temperature to the carbonization temperature of 50-300°C, preferably 100-240°C; the pressure is reduced to 0.1-2.0MPa, preferably 0.4-1.6MPa; and then the gas is replaced with synthesis gas: (1vol%-10vol%) CO-(90vol%-99vol%) H 2 , preferably (2vol%~8vol%)CO-(92vol%~98vol%)H 2 ; Space velocity 1 ~ 20L / g / h, maintain 1 ~ 5 hours, preferably 2 ~ 4 hours.

[0053] Preferably, the main catalyst passivation comprises the following steps:

[0054] The iron-based catalyst was deactivated in a reactor under the following conditions,

[0055] The temperature is reduced from the carbonization temperature to the passivation temperature of 10-200°C, preferably 30-120°C; the pressure is 0.1-1.0 MPa, preferably 0.2-0.5 MPa; and then the gas is replaced with the passivation gas: (0.1 vol%-5 vol%) O 2 -(95vol%~99vol%)N 2 , preferably (1vol%~4vol%)CO-(96vol%~99vol%)N 2 ; Space velocity 1 to 10 L / g / h; Maintain for 0.5 to 3 hours, preferably 1 to 2 hours.

[0056] Preferably, in step 4), based on 100 wt% of the total mass of the auxiliary agent, the auxiliary agent comprises:

[0057] (a) one or more alkali metals and their oxides, the content of which is 10wt% to 60wt%, the alkali metals are preferably K and / or Na;

[0058] (b) one or more rare earth metals and their oxides, the content of which is 1wt% to 10wt%, and the rare earth metal is preferably lanthanum and / or cerium;

[0059] (c) manganese and its oxides, in an amount of 5 wt% to 40 wt%;

[0060] (d) zinc and its oxides, in an amount of 2 wt% to 15 wt%; and

[0061] (e) Boron and its oxides, in an amount of 5 wt% to 25 wt%.

[0062] Preferably, in step 4), the mass ratio of the main catalyst to the auxiliary agent is (20-50):1, preferably (25-40):1.

[0063] Preferably, in step 4), the concentration of the mixture of the main catalyst and the auxiliary agent in the slurry after impregnation is (the ratio of the sum of the mass of the main catalyst and the auxiliary agent to the sum of the mass of the main catalyst, the auxiliary agent and the impregnation liquid) 10wt% to 60wt%, preferably 20wt% to 50wt%.

[0064] Preferably, step 4) is carried out under the following conditions:

[0065] The impregnation temperature is 100-200°C, preferably 120-180°C;

[0066] Pressure 0.1-0.5 MPa, preferably 0.2-0.35 MPa;

[0067] The gas is pure nitrogen;

[0068] Air velocity 1~10L / g / h;

[0069] The immersion time is maintained at 2 to 6 hours, preferably 3 to 5 hours.

[0070] According to a second aspect of the present invention, there is provided a pretreated Fischer-Tropsch synthesis catalyst obtained by the method for pretreating a Fischer-Tropsch synthesis catalyst according to the present invention.

[0071] According to a third aspect of the present invention, there is provided a method for converting synthesis gas using a pretreated Fischer-Tropsch synthesis catalyst, comprising the following steps:

[0072] i) inducing a pretreated Fischer-Tropsch synthesis catalyst using approximate reaction conditions;

[0073] ii) adding the catalyst system obtained in step i) into a slurry bed reactor and reacting under the following conditions:

[0074] Temperature 260-300°C, preferably 275-295°C;

[0075] Pressure 2.0-4.0 MPa, preferably 2.8-3.6 MPa;

[0076] Space velocity 2 to 15 L / g / h, preferably 4 to 13 L / g / h;

[0077] Syngas H 2 / CO=1.6-2.5, preferably 1.8-2.3.

[0078] Preferably, the approximate reaction condition induction in step i) comprises the following steps:

[0079] The pretreated Fischer-Tropsch synthesis catalyst was added to the stirred tank reactor, and the synthesis gas was introduced to react, wherein H 2 / CO is 1.7 to 3.0, preferably 1.9 to 2.8; temperature is 245 to 295°C, preferably 260 to 290°C; pressure is 1.5 to 3.8 MPa, preferably 2.3 to 3.4 MPa; space velocity is 1.4 to 13.5 L / g / h, preferably 2.8 to 12.7 L / g / h; retention time is 1 to 5 hours; wherein, the synthesis gas H 2 The ratio of syngas to CO is 0.1-0.5 higher than that in step ii); the syngas space velocity is 10%-30% lower than that in step ii); the pressure is 0.2-0.5 MPa lower than that in step ii); and the reactor temperature is 5-15° C. lower than that in step ii).

[0080] The method for converting synthesis gas using a pretreated Fischer-Tropsch synthesis catalyst also includes the following steps:

[0081] iii) During the reaction, the pretreated main catalyst and / or auxiliary agent are added and the composition of the auxiliary agent is adjusted according to the following conditions:

[0082] (iii-1) When the CO conversion rate decreases by more than 2%, preferably more than 5%, compared to the situation measured after the previous addition of the pre-treated main catalyst and / or the auxiliary agent, and CO 2 The selectivity increase was less than 0.5% and CH 4 When the selectivity increases by less than 0.4%, a Fischer-Tropsch synthesis catalyst pretreated according to the present invention is added; the weight of the main catalyst in the pretreated Fischer-Tropsch synthesis catalyst added is 1% to 12% of the weight of the main catalyst in the catalyst system of the reactor, preferably 2% to 10%;

[0083] (iii-2) When the CO conversion rate decreases by less than 2% compared to the case measured after the previous addition of the pretreated Fischer-Tropsch synthesis catalyst or additive, but the CO 2 When the selectivity increases by more than 0.5%, only the auxiliary agent is added, and the weight ratio of the amount of the added auxiliary agent to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the auxiliary agent in step i), wherein the proportion of alkali metals and their oxides in the auxiliary agent is reduced relative to the auxiliary agent in step i), and preferably, the added auxiliary agent comprises:

[0084] (a-iii-2) one or more alkali metals and their oxides, the content of which is 5wt% to 50wt%, the alkali metal is preferably K and / or Na;

[0085] (b-iii-2) one or more rare earth metals and their oxides, the content of which is 1wt% to 10wt%, and the rare earth metal is preferably lanthanum and / or cerium;

[0086] (c-iii-2) manganese and its oxides, in an amount of 5 wt% to 43 wt%;

[0087] (d-iii-2) zinc and its oxides, in an amount of 2 wt% to 17 wt%; and

[0088] (e-iii-2) boron and its oxides, in an amount of 5 wt% to 25 wt%;

[0089] (iii-3) When the CO conversion rate decreases by less than 2% compared with the case where the pretreated Fischer-Tropsch synthesis catalyst or additive is added, but the CH 4 When the selectivity increases by more than 0.4%, only the auxiliary agent is added, and the weight ratio of the amount of the added auxiliary agent to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the auxiliary agent in step i), wherein the proportion of alkali metals and their oxides, Zn and oxides in the auxiliary agent is increased relative to the auxiliary agent in step i), and preferably, the added auxiliary agent comprises:

[0090] (a-iii-3) one or more alkali metals and their oxides, the content of which is 12 wt% to 68 wt%, the alkali metals are preferably K and / or Na;

[0091] (b-iii-3) one or more rare earth metals and their oxides, the content of which is 1wt% to 10wt%, and the rare earth metal is preferably lanthanum and / or cerium;

[0092] (c-iii-3) manganese and its oxides, in an amount of 5 wt% to 40 wt%;

[0093] (d-iii-3) zinc and its oxides, in an amount of 3 wt% to 15 wt%; and

[0094] (e-iii-3) boron and its oxides, in an amount of 5 wt% to 25 wt%;

[0095] (iii-4) When the CO conversion rate decreases by more than 2% (preferably more than 5%) compared to the previous measurement after adding the pretreated Fischer-Tropsch synthesis catalyst or additive, and CH 4 When the selectivity increases by more than 0.4% (preferably more than 1%), a mixture of the main catalyst and the auxiliary agent pretreated in steps 1) to 4) is added, wherein the weight of the added main catalyst is 1% to 12% of the weight of the main catalyst of the catalyst system in the reactor, preferably 2% to 10%, and the weight ratio of the added auxiliary agent to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the auxiliary agent in step i), wherein the proportion of Mn and rare earth metals and oxides in the auxiliary agent is increased relative to the auxiliary agent in step i), and preferably, the added auxiliary agent comprises:

[0096] (a-iii-4) one or more alkali metals and their oxides, the content of which is 10wt% to 60wt%, the alkali metal is preferably K and / or Na;

[0097] (b-iii-4) one or more rare earth metals and their oxides, the content of which is 1.5wt% to 12wt%, and the rare earth metal is preferably lanthanum and / or cerium;

[0098] (c-iii-4) manganese and its oxides, in an amount of 7 wt% to 44 wt%;

[0099] (d-iii-4) zinc and its oxides, in an amount of 2 wt% to 15 wt%; and

[0100] (e-iii-4) boron and its oxides, in an amount of 5 wt% to 25 wt%;

[0101] (iii-5) When the CO conversion rate decreases by less than 2% and the CO 2 When the selectivity increases by less than 0.5%, the concentration of oxides in the synthetic water is reduced by adding only an auxiliary agent, and the weight ratio of the added auxiliary agent to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the auxiliary agent in step 4), wherein the proportion of alkali metals and their oxides in the auxiliary agent is reduced relative to the auxiliary agent in step i). Preferably, the added auxiliary agent comprises:

[0102] (a-iii-5) one or more alkali metals and their oxides, the content of which is 6wt% to 52wt%, the alkali metal is preferably K and / or Na;

[0103] (b-iii-5) one or more rare earth metals and their oxides, the content of which is 1wt% to 10wt%, and the rare earth metal is preferably lanthanum and / or cerium;

[0104] (c-iii-5) manganese and its oxides, in an amount of 5 wt% to 40 wt%;

[0105] (d-iii-5) zinc and its oxides, in an amount of 2 wt% to 10 wt%; and

[0106] (e-iii-5) Boron and its oxides, in an amount of 5 wt% to 20 wt%.

[0107] It is worth noting that the value of the CO conversion rate decrease here refers to the difference between the two measured values, and the product (CO 2 or CH 4 )The selectivity fluctuation value also refers to the difference between two measurements.

[0108] When two or more of (iii-1) to (iii-5) are satisfied at the same time, it is sufficient to implement the adjustment according to any one of them.

[0109] Beneficial Effects

[0110] 1. After reduction and carbonization, the passivation process is introduced to steadily and slowly release the catalyst activity to avoid rapid deactivation.

[0111] 2. After the main catalyst is reduced, carbonized and passivated, add the auxiliary agent and mix it. In this way, the auxiliary agent will not participate in the reduction and carbonization process of the iron oxide and will not affect the reduction and carbonization effect.

[0112] 3. Use liquid wax, naphtha or heavy diesel to mix the main catalyst and the additive into a slurry mixture, which is convenient for transportation and pipeline transportation.

[0113] 4. By adjusting the composition and proportion of the added additives, the negative impact of the catalyst performance (activity, selectivity and stability) deviating from the design value caused by uncontrollable factors during the reaction process can be reduced. DETAILED DESCRIPTION

[0114] The present invention will be described in detail below in conjunction with embodiments. It should be understood that the embodiments below are only used to illustrate the purpose of the present invention rather than to limit the scope of the present invention.

[0115] Example 1

[0116] 1) Main catalyst reduction: The precipitated iron-based catalyst is reduced with hydrogen in a fluidized bed reactor. The active component of the catalyst is Fe 2 O 3 , the carrier is SiO 2 , and a small amount of Cu, the weight ratio of each component is Fe: SiO 2 ∶Cu=100∶20∶0.5. The process is as follows: Stage 1: Initial temperature to 180℃, heating rate 50℃ / h, pure N 2 atmosphere, air velocity 8L / g / h, pressure 0.2MPa; second stage: 180℃ to 280℃, heating rate 20℃ / h, 50vol%N 2 -50vol%H 2 , air velocity 7L / g / h, pressure 0.5MPa; third stage: 280℃ to final reduction temperature 340℃, heating rate 12℃ / h, 10vol%N 2 -90vol%H 2 , space velocity 9L / g / h, pressure 2.0MPa; Fourth stage: final reduction temperature 340℃, maintain for 8h.

[0117] 2) Carbonization of the main catalyst: The reactor temperature is reduced from the final reduction temperature of 340°C to the carbonization temperature of 180°C, the pressure is reduced to 1.0 MPa, and then the gas is replaced with synthesis gas: 5 vol% CO-95 vol% H 2 , 10L / g / h, maintain for 3 hours.

[0118] 3) Main catalyst passivation: The reactor temperature is reduced from the carbonization temperature of 180°C to the passivation temperature of 40°C, the pressure is 0.3MPa, and then the gas is replaced with the passivation gas: 1.5vol%O 2 -98.5vol%N 2 , space velocity 2L / g / h, maintain for 1.5 hours.

[0119] 4) The mixture of the main catalyst and the auxiliary agent is impregnated and mixed with liquid wax in a 1-liter stirred tank reactor. The mass ratio of the main catalyst to the auxiliary agent is 30:1, and the auxiliary agent composition is as follows:

[0120] (a) alkali metal K and its oxides, with a mass content of 45%;

[0121] (b) Rare earth metals lanthanum, cerium and their oxides, with a mass content of 4%;

[0122] (c) Manganese and its oxides, with a mass content of 35%;

[0123] (d) Zinc and its oxides, 6% by mass;

[0124] (e) Boron and its oxides, content by mass: 10%.

[0125] The mass concentration of the slurry in the stirred tank is 30%, the temperature is 130° C., the pressure is 0.25 MPa, the gas is pure nitrogen, the air velocity is 4 L / g / h, and the impregnation mixing time is maintained for 3.5 hours.

[0126] Example 2

[0127] i) The mixture of the main catalyst and the auxiliary agent obtained in Example 1 was induced in a stirred tank reactor under similar reaction conditions. The gas was replaced with synthesis gas, the synthesis gas H 2 The ratio of syngas to CO is 2.2; the synthesis gas space velocity is 8 L / g / h; then the pressure is adjusted to 2.7 MPa; finally, the temperature is started to rise, and the reactor temperature is raised to 280°C and maintained for 2 hours.

[0128] ii) adding the catalyst system obtained in step i) into a slurry bed reactor to convert the synthesis gas into hydrocarbons with high value-added products as target products; the reaction conditions are as follows: temperature 290°C, pressure 3.0MPa, space velocity 9L / g / h, synthesis gas H 2 / CO=2.0.

[0129] The reaction performance is as follows: reaction time 50 hours, CO conversion rate 71%, CO 2 Selectivity 10%, CH 4 Selectivity 7%, C 2 -C 4 Olefin selectivity 25%, C 5+ Selectivity 57%, concentration of oxygenated compounds in synthetic water 3.5%.

[0130] After 150 hours of reaction, the catalyst activity, i.e., CO conversion rate, dropped to 69%, and the deactivation rate dropped by 2 percentage points every 100 hours. 2 and CH 4 The selectivity is relatively stable, 10.4% and 7.3%, respectively. 2 -C 4 Olefin selectivity 25.3%, C 5 + Selectivity 56.7%, oxygen-containing compound concentration in synthetic water 3.6%. The catalyst pretreated in Example 1 was added, wherein the amount of the main catalyst added was 4% of the weight of the main catalyst in the catalyst system of the reactor.

[0131] After 250 hours of reaction, the CO conversion rate of the catalyst became 67.8%, and the deactivation rate decreased by 1.2 percentage points every 100 hours. 2 and CH 4 The selectivities were 11.0% and 7.1%, respectively, and C 2 -C 4 Olefin selectivity 25.7%, C 5 + selectivity 57.1%, oxygen-containing compound concentration in synthetic water 3.7%. It can be seen that compared with the deactivation rate from 50 hours to 150 hours, the deactivation rate from 150 hours to 250 hours did not decrease significantly, and the stability of the catalyst was improved, but CO 2 The selectivity increased by 0.6%. The auxiliary agent was added, wherein the weight of the added auxiliary agent was 1 / 30 of the weight of the main catalyst in the catalyst system of the reactor, and relative to 100wt% of the total weight of the added auxiliary agent, the proportion of K and its oxide in the auxiliary agent was 43%, the proportion of Zn and its oxide was 6%, the proportion of rare earth metal lanthanum, cerium and their oxides was 4%, the proportion of Mn and its oxide was 36%, and the proportion of boron and its oxide was 11%.

[0132] Reaction time 350 hours, CO conversion rate 67.5%, CO 2 Selectivity 11.2%, CH 4 Selectivity 7.6%, C 2 -C 4 Olefin selectivity 25.2%, C 5 + selectivity 56.7%, the concentration of oxygenated compounds in synthetic water 3.7%. It can be seen that compared with 250 hours, CO 2 The selectivity decreases, but CH 4The selectivity increased by 0.5%. The auxiliary agent was added, wherein the weight of the added auxiliary agent was 1 / 30 of the weight of the main catalyst in the catalyst system of the reactor, and relative to 100wt% of the total weight of the added auxiliary agent, the proportion of K and its oxide in the auxiliary agent was 46%, the proportion of Zn and its oxide was 7%, the proportion of rare earth metal lanthanum, cerium and their oxides was 4%, the proportion of Mn and its oxide was 34%, and the proportion of boron and its oxide was 9%.

[0133] After 450 hours of reaction, the CO conversion rate of the catalyst was 67.0%, and the CO 2 Selectivity 11.5%, CH 4 Selectivity 7.8%, C 2 -C 4 Olefin selectivity 26.4%, C 5 + selectivity is 58.3%, and the concentration of oxygenated compounds in synthetic water is 3.8%. It can be seen that compared with 350 hours, CH 4 The selectivity rise is reduced, C 2 -C 4 Olefin selectivity and C 5 + Increased selectivity. No need to add main catalyst or auxiliary agent.

[0134] After 550 hours of reaction, the CO conversion rate of the catalyst was 64.5%, and the CO 2 Selectivity 11.9%, CH 4 Selectivity 8.3%, C 2 -C 4 Olefin selectivity 25.9%, C 5 + selectivity 58.4%, the concentration of oxygenated compounds in synthetic water 4.0%. It can be seen that compared with 350 hours, the CO conversion rate decreased by 3%, CO 2 The selectivity increased by 0.7%, CH 4 The selectivity increases by 0.7%. The catalyst pretreated according to the method in Example 1 is added in an amount of 5% of the weight of the main catalyst in the catalyst system of the reactor, and the composition of the additives is adjusted. Relative to 100wt% of the total weight of the added additives, the proportion of K and its oxide in the additives is 44%, the proportion of Zn and its oxide is 6.5%, the proportion of rare earth metal lanthanum, cerium and their oxides is 4.5%, the proportion of Mn and its oxide is 37%, and the proportion of boron and its oxide is 8%.

[0135] After 650 hours of reaction, the CO conversion rate of the catalyst was 64.1%, and the CO 2 Selectivity 12.2%, CH 4 Selectivity 8.6%, C 2 -C 4 Olefin selectivity 25.5%, C 5+ selectivity is 58.1%, and the concentration of oxygenated compounds in synthetic water is 4.1%. It can be seen that the decrease in CO conversion rate is smaller, and CH 4 The selectivity increase is reduced, CO 2 The selectivity does not change much. Adding an auxiliary agent, wherein the weight of the added auxiliary agent is 1 / 30 of the weight of the main catalyst in the catalyst system of the reactor, and relative to 100wt% of the total weight of the added auxiliary agent, the proportion of K and its oxide in the auxiliary agent is 40%, the proportion of Zn and its oxide is 7.5%, the proportion of rare earth metal lanthanum, cerium and its oxide is 4%, the proportion of Mn and its oxide is 39%, and the proportion of boron and its oxide is 9.5%.

[0136] After 750 hours of reaction, the CO conversion rate of the catalyst was 64.0%, and the CO 2 Selectivity 12.4%, CH 4 Selectivity 8.7%, C 2 -C 4 Olefin selectivity 25.4%, C 5 + Selectivity 58.3%, concentration of oxygenated compounds in synthetic water 3.3%. It can be seen that the concentration of oxygenated compounds in synthetic water has dropped significantly.

[0137] Comparative Example 1

[0138] The main catalyst reduction, carbonization, passivation, and impregnation and mixing with the auxiliary agent were carried out in the same steps as in Example 1; and the induction step of the catalyst system was carried out in the same manner as in Example 2 and the conversion reaction of the synthesis gas was carried out under the same reaction conditions. During the conversion reaction, the main catalyst and auxiliary agent were not added.

[0139] The reaction time was 50 hours, the CO conversion rate was 70.8%, and the CO 2 Selectivity 10.1%, CH 4 Selectivity 6.9%, C 2 -C 4 Olefin selectivity 25.2%, C 5 + Selectivity 56.9%, concentration of oxygen-containing compounds in synthetic water 3.4%, catalyst performance is not much different from that in Example 1.

[0140] Reaction time 150 hours, CO conversion rate 68.8%, CO 2 Selectivity 10.5%, CH 4 Selectivity 7.3%, C 2 -C 4 Olefin selectivity 25.2%, C 5 + Selectivity 56.9%, concentration of oxygen-containing compounds in synthetic water 3.5%, catalyst performance is not much different from that of Example 1.

[0141] The pre-treated main catalyst and the auxiliary agent mixture was not added. After 250 hours of reaction, the CO conversion rate of the catalyst became 66.6%, and the CO 2 Selectivity 11.1%, CH 4 Selectivity 7.7%, C 2 -C 4 Olefin selectivity 25.0%, C 5 + Selectivity 56.3%, oxygen-containing compound concentration in synthetic water 3.6%. Compared with Example 1, the catalyst deactivation rate did not decrease significantly.

[0142] Reaction time 350 hours, CO conversion rate 65.5%, CO 2 Selectivity 11.8%, CH 4 Selectivity 8.0%, C 2 -C 4 Olefin selectivity 24.7%, C 5 + Selectivity 56.1%, concentration of oxygenated compounds in synthetic water 3.7%.

[0143] After 450 hours of reaction, the CO conversion rate of the catalyst was 65.0%, and the CO 2 Selectivity 12.4%, CH 4 Selectivity 8.3%, C 2 -C 4 Olefin selectivity 24.2%, C 5 + Selectivity 55.7%, concentration of oxygenated compounds in synthetic water 3.8%.

[0144] After 550 hours of reaction, the CO conversion rate of the catalyst was 64.2%. 2 Selectivity 12.9%, CH 4 Selectivity 8.6%, C 2 -C 4 Olefin selectivity 23.8%, C 5 + Selectivity 55.3%, concentration of oxygenated compounds in synthetic water 3.9%.

[0145] After 650 hours of reaction, the CO conversion rate of the catalyst was 63.1%, and the CO 2 Selectivity 13.9%, CH 4 Selectivity 9.2%, C 2 -C 4 Olefin selectivity 23.2%, C 5 + Selectivity 55.1%, concentration of oxygenated compounds in synthetic water 4.1%.

[0146] After 750 hours of reaction, the CO conversion rate of the catalyst was 62.3%, and the CO 2 Selectivity 14.6%, CH 4Selectivity 9.7%, C 2 -C 4 Olefin selectivity 22.6%, C 5 + Selectivity 55.0%, concentration of oxygenated compounds in synthetic water 4.2%.

[0147] Compared with Example 2, the activity of the catalyst in Comparative Example 1 continued to decrease, and the byproduct CO 2 and CH 4 The selectivity continued to increase, and the target product C 2 -C 4 Olefin selectivity and C 5 +The selectivity continued to decrease and the concentration of oxygenated compounds in the synthetic water continued to increase.

[0148] Comparative Example 2

[0149] The main catalyst reduction, carbonization, and impregnation and mixing steps with the auxiliary agent were carried out in the same manner as in Example 1, without passivation and induction. Except that the catalyst was used instead of the catalyst system in Example 2, the reaction was carried out under the same conditions as step ii) in Example 2. No additional main catalyst and auxiliary agent were added during the conversion of the synthesis gas.

[0150] The reaction time was 50 hours, the CO conversion rate was 77.6%, and the CO 2 Selectivity 10.9%, CH 4 Selectivity 7.2%, C 2 -C 4 Olefin selectivity 25.0%, C 5 + Selectivity 56.5%, oxygen-containing compound concentration in synthetic water 3.5%. Compared with Example 2, the catalyst activity is higher.

[0151] The reaction time was 150 hours, the CO conversion rate was 65.7%, and the deactivation rate decreased by 11.9 percentage points per 100 hours (2 percentage points in Example 1); CO 2 Selectivity 12.5%, an increase of 1.6 percentage points (0.4 percentage points in Example 2); CH 4 Selectivity 8.3%, an increase of 1.1 percentage points (0.3 percentage points in Example 2); C 2 -C 4 Olefin selectivity 21.2%, down 3.8 percentage points (increased 0.3 percentage points in Example 2); C 5 + selectivity was 54.9%, down 1.6 percentage points (down 0.3 percentage points in Example 2); the concentration of oxygenated compounds in the synthetic water was 3.7%, up 0.2 percentage points (0.1 percentage points in Example 2). Due to the lack of passivation and induction steps, the catalyst deactivation of Comparative Example 2 was significantly accelerated compared with Example 2, and the byproduct CO2 and CH 4 The selectivity increased significantly, and the target product C 2 -C 4 Olefin selectivity and C 5 + Lower selectivity and poorer catalyst performance.

Claims

1. A method for pretreating a Fischer-Tropsch synthesis catalyst, comprising the following steps: 1) Reduction of a main catalyst, wherein the main catalyst is an iron-based catalyst; 2) Carbonization of the main catalyst; 3) deactivation of the primary catalyst; and 4) impregnating a mixture of the auxiliary agent and the main catalyst obtained in step 3) with liquid wax, naphtha or heavy diesel oil.

2. The method for pretreating a Fischer-Tropsch synthesis catalyst according to claim 1, in, The iron-based catalyst comprises iron oxide, Cu and its oxide and a carrier, wherein the mass ratio of Fe:carrier:Cu=100:15-45:0.1-4.5; and / or The carrier is selected from SiO 2 、Al 2 O 3 , one or more of carbon materials and molecular sieves, etc.; and / or The reduction of the main catalyst comprises the following steps: The iron-based catalyst is reduced in a reactor under the following conditions, 1-1) The first stage: the starting temperature reaches 180°C, Heating rate: 20-80°C / h, preferably 30-60°C / h, Pure N 2 atmosphere, Air velocity 1~15L / g / h, Pressure 0.01-0.3 MPa, preferably 0.05-0.25 MPa; 1-2) Second stage: 180℃ to 280℃, Heating rate 10-35°C / h, preferably 15-25°C / h, (40vol%~60vol%)N 2 -(40vol%~60vol%)H 2 atmosphere, Air velocity 2~14L / g / h, Pressure 0.2-2.0 MPa, preferably 0.4-1.5 MPa; 1-3) The third stage: 280°C to the final reduction temperature of 300-400°C, preferably 320-360°C, Heating rate 6-18°C / h, preferably 8-15°C / h, (5vol%~20vol%)N 2 -(80vol%~95vol%)H 2 atmosphere, Air velocity 2~14L / g / h, Pressure 1.0-3.5 MPa, preferably 1.5-2.5 MPa; 1-4) The fourth stage: the final reduction temperature is maintained for 2 to 16 hours, preferably 6 to 12 hours, (5vol%~20vol%)N 2 -(80vol%~95vol%)H 2 atmosphere, Air velocity 2~14L / g / h, The pressure is 1.0 to 3.5 MPa, preferably 1.5 to 2.5 MPa.

3. The method for pretreating a Fischer-Tropsch synthesis catalyst according to claim 1, in, The carbonization of the main catalyst includes the following steps: The iron-based catalyst is carbonized in a reactor under the following conditions: The temperature is reduced from the final reduction temperature to the carbonization temperature of 50-300°C, preferably 100-240°C; the pressure is reduced to 0.1-2.0MPa, preferably 0.4-1.6MPa; and then the gas is replaced with synthesis gas: (1vol%-10vol%) CO-(90vol%-99vol%) H 2 , preferably (2vol%~8vol%)CO-(92vol%~98vol%)H 2 ; Space velocity 1 to 20 L / g / h, maintained for 1 to 5 hours, preferably 2 to 4 hours; and / or The main catalyst passivation includes the following steps: The iron-based catalyst was deactivated in a reactor under the following conditions, The temperature is reduced from the carbonization temperature to the passivation temperature of 10-200°C, preferably 30-120°C; the pressure is 0.1-1.0 MPa, preferably 0.2-0.5 MPa; and then the gas is replaced with the passivation gas: (0.1 vol%-5 vol%) O 2 -(95vol%~99vol%)N 2 , preferably (1vol%~4vol%)CO-(96vol%~99vol%)N 2 ; Space velocity 1 to 10 L / g / h; Maintain for 0.5 to 3 hours, preferably 1 to 2 hours; and / or In step 4), based on 100 wt% of the total mass of the auxiliary agent, the auxiliary agent comprises: (a) one or more alkali metals and their oxides, the content of which is 10wt% to 60wt%, the alkali metals are preferably K and / or Na; (b) one or more rare earth metals and their oxides, the content of which is 1wt% to 10wt%, and the rare earth metal is preferably lanthanum and / or cerium; (c) manganese and its oxides, in an amount of 5 wt% to 40 wt%; (d) zinc and its oxides, in an amount of 2 wt% to 15 wt%; and (e) Boron and its oxides, in an amount of 5 wt% to 25 wt%.

4. A method for pretreating a Fischer-Tropsch synthesis catalyst according to any one of claims 1 to 3, in, In step 4), the mass ratio of the main catalyst to the auxiliary agent is (20-50):1, preferably (25-40):1; and / or In step 4), the concentration of the mixture of the main catalyst and the auxiliary agent in the slurry after impregnation is (the ratio of the sum of the mass of the main catalyst and the auxiliary agent to the sum of the mass of the main catalyst, the auxiliary agent and the impregnation liquid) 10wt% to 60wt%, preferably 20wt% to 50wt%; and / or Step 4) is carried out under the following conditions: The impregnation temperature is 100-200°C, preferably 120-180°C; Pressure 0.1-0.5 MPa, preferably 0.2-0.35 MPa; The gas is pure nitrogen; Air velocity 1~10L / g / h; The immersion time is maintained at 2 to 6 hours, preferably 3 to 5 hours.

5. A pretreated Fischer-Tropsch synthesis catalyst obtained by the method for pretreating a Fischer-Tropsch synthesis catalyst according to any one of claims 1 to 4.

6. A method for converting synthesis gas using the pretreated Fischer-Tropsch synthesis catalyst according to claim 5, comprising the following steps: i) inducing a product obtained by pretreating a Fischer-Tropsch synthesis catalyst using approximate reaction conditions; ii) adding the catalyst system obtained in step i) into a slurry bed reactor and reacting under the following conditions: Temperature 260-300°C, preferably 275-295°C; Pressure 2.0-4.0 MPa, preferably 2.8-3.6 MPa; Space velocity 2 to 15 L / g / h, preferably 4 to 13 L / g / h; Syngas H 2 / CO=1.6-2.5, preferably 1.8-2.

3.

7. The method for converting synthesis gas using a pretreated Fischer-Tropsch synthesis catalyst according to claim 6, in, The approximate reaction condition induction in step i) comprises the following steps: The product obtained by pretreating the Fischer-Tropsch synthesis catalyst is added to a stirred tank reactor, and synthesis gas is introduced to react, wherein H 2 / CO is 1.7 to 3.0, preferably 1.9 to 2.8; temperature is 245 to 295°C, preferably 260 to 290°C; pressure is 1.5 to 3.8 MPa, preferably 2.3 to 3.4 MPa; space velocity is 1.4 to 13.5 L / g / h, preferably 2.8 to 12.7 L / g / h; retention time is 1 to 5 hours; wherein, the synthesis gas H 2 The ratio of syngas to CO is 0.1-0.5 higher than that in step ii); the syngas space velocity is 10%-30% lower than that in step ii); the pressure is 0.2-0.5 MPa lower than that in step ii); and the reactor temperature is 5-15° C. lower than that in step ii).

8. The method for converting synthesis gas using a pretreated Fischer-Tropsch synthesis catalyst according to claim 6 or 7, in, The method for converting synthesis gas using a pretreated Fischer-Tropsch synthesis catalyst also includes the following steps: iii) During the reaction, the pretreated main catalyst and / or auxiliary agent are added and the composition of the auxiliary agent is adjusted according to the following conditions: (iii-1) When the CO conversion rate decreases by more than 2%, preferably more than 5%, compared to the situation measured after the previous addition of the pre-treated main catalyst and / or the auxiliary agent, and CO 2 The selectivity increase was less than 0.5% and CH 4 When the selectivity increase is less than 0.4%, a pretreated Fischer-Tropsch synthesis catalyst obtained by the method for pretreating a Fischer-Tropsch synthesis catalyst according to claim 1 is added; the weight of the main catalyst in the pretreated Fischer-Tropsch synthesis catalyst added is 1% to 12% of the weight of the main catalyst in the catalyst system of the reactor, preferably 2% to 10%; (iii-2) When the CO conversion rate decreases by less than 2% compared to the case measured after the previous addition of the pretreated Fischer-Tropsch synthesis catalyst or additive, but the CO 2 When the selectivity increases by more than 0.5%, only the auxiliary agent is added, and the weight ratio of the amount of the added auxiliary agent to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the auxiliary agent in step i), wherein the proportion of the alkali metal and its oxide in the auxiliary agent is reduced relative to the auxiliary agent in step i): (iii-3) When the CO conversion rate decreases by less than 2% compared with the case where the pretreated Fischer-Tropsch synthesis catalyst or additive is added, but the CH 4 When the selectivity increases by more than 0.4%, only the auxiliary agent is added, and the weight ratio of the amount of the added auxiliary agent to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the auxiliary agent in step i), wherein the proportion of alkali metal, Zn and oxide in the auxiliary agent is increased relative to the auxiliary agent in step i); (iii-4) When the CO conversion rate decreases by more than 2%, preferably more than 5%, compared to the situation measured after the previous addition of the pretreated Fischer-Tropsch synthesis catalyst or the additive, and CH 4 When the selectivity is increased by more than 0.4%, preferably more than 1%, a mixture of the main catalyst and the auxiliary agent pretreated in step 1) to step 4) of claim 1 is added, wherein the weight of the main catalyst added is 1% to 12% of the weight of the main catalyst in the catalyst system of the reactor, preferably 2% to 10%, and the weight ratio of the added auxiliary agent to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the auxiliary agent in step i), wherein the proportion of Mn and rare earth metals and oxides in the auxiliary agent is increased relative to the auxiliary agent in step i); (iii-5) When the CO conversion rate decreases by less than 2% and the CO 2 When the selectivity increases by less than 0.5%, the concentration of oxides in the synthetic water needs to be reduced, and only additional additives are added. The weight ratio of the amount of the added additive to the main catalyst in the catalyst system is consistent with the weight ratio of the main catalyst to the additive in step i), wherein the proportion of alkali metals and their oxides in the additive is reduced relative to the additive in step i).

9. The method for converting synthesis gas using a pretreated Fischer-Tropsch synthesis catalyst according to claim 8, in, In (iii-2), the additives added include: (a-iii-2) one or more alkali metals and their oxides, in an amount of 5 wt% to 50 wt%; (b-iii-2) one or more rare earth metals and their oxides, in an amount of 1 wt% to 10 wt%; (c-iii-2) manganese and its oxides, in an amount of 5 wt% to 43 wt%; (d-iii-2) zinc and its oxides, in an amount of 2 wt% to 17 wt%; and (e-iii-2) boron and its oxides, in an amount of 5 wt% to 25 wt%; and / or In (iii-3), the additives added include: (a-iii-3) one or more alkali metals and their oxides, in an amount of 12 wt% to 68 wt%; (b-iii-3) one or more rare earth metals and their oxides, in an amount of 1 wt% to 10 wt%; (c-iii-3) manganese and its oxides, in an amount of 5 wt% to 40 wt%; (d-iii-3) zinc and its oxides, in an amount of 3 wt% to 15 wt%; and (e-iii-3) boron and its oxides, in an amount of 5 wt% to 25 wt%; and / or In (iii-4), the additives added include: (a-iii-4) one or more alkali metals and their oxides, in an amount of 10 wt% to 60 wt%; (b-iii-4) one or more rare earth metals and their oxides, in an amount of 1.5 wt% to 12 wt%; (c-iii-4) manganese and its oxides, in an amount of 7 wt% to 44 wt%; (d-iii-4) zinc and its oxides, in an amount of 2 wt% to 15 wt%; and (e-iii-4) boron and its oxides, in an amount of 5 wt% to 25 wt%; and / or In (iii-5), the auxiliary agent added comprises: (a-iii-5) one or more alkali metals and their oxides, in an amount of 6 wt% to 52 wt%; (b-iii-5) one or more rare earth metals and their oxides, in an amount of 1 wt% to 10 wt%; (c-iii-5) manganese and its oxides, in an amount of 5 wt% to 40 wt%; (d-iii-5) zinc and its oxides, in an amount of 2 wt% to 10 wt%; and (e-iii-5) Boron and its oxides, in an amount of 5 wt% to 20 wt%.

10. The method for converting synthesis gas using a pretreated Fischer-Tropsch synthesis catalyst according to claim 9, in, The alkali metal is K and / or Na; and / or The rare earth metal is lanthanum and / or cerium.