Fischer-tropsch wax finishing process and fischer-tropsch wax product

Abstract

The application provides a Fischer-Tropsch wax refining method and a Fischer-Tropsch wax product. The method comprises the following steps: S1, coating a first pre-coating liquid on a filtering device to form a first filter cake, wherein the first pre-coating liquid comprises a first adsorbent and a dispersant, and the particle size of the first adsorbent is 50-150 mu m; S2, coating a second pre-coating liquid on the surface of the first filter cake to form a second filter cake, thereby obtaining a pre-coating filtering layer, wherein the second pre-coating liquid comprises a second adsorbent and a dispersant, and the particle size of the second adsorbent is less than 50 mu m; and S3, filtering the Fischer-Tropsch wax to be treated through the pre-coating filtering layer to obtain a qualified Fischer-Tropsch wax product and a wax-containing waste residue. The Fischer-Tropsch wax is pre-coated and filtered in a two-time coating mode, the adsorption performance of the Fischer-Tropsch wax refining adsorbent is improved, the impurity element removal efficiency is high, the wax-containing waste residue generated after the filtration can be incinerated to generate heat for further utilization, and the process route is simple, easy for industrialized production, low in operation cost and high in economic benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of Fischer-Tropsch synthesis wax refining, in particular to a Fischer-Tropsch wax refining method and a Fischer-Tropsch wax product. BACKGROUND

[0002] Fischer-Tropsch synthesis wax is one of the main products in Fischer-Tropsch synthesis (F-T synthesis) reaction and is also an important raw material for hydrofining. In the process of F-T synthesis of heavy hydrocarbons, a large amount of heavy wax product generated in the reactor is discharged through the built-in wax filter pipe of the reactor, and the stable wax obtained after stripping still contains a small amount of catalyst and other solid impurities; at the same time, when the catalyst is replaced online, the residue wax containing 8-10% catalyst is discharged from the reactor, and the above two primary products need to be further refined and purified before being sent to the downstream hydrofining reaction unit. The leaf filter of the wax filtering device removes the catalyst solid particles in it by using the principle of adsorption and interception to obtain a coal-based Fischer-Tropsch synthesis wax product (iron ion content <5 ppm), and if the refining effect does not meet the standard, it will cause the downstream hydrofining reaction bed to be blocked, the pressure difference to increase, and the oil product yield and quality to be unqualified, which cannot meet the requirements of the subsequent production device.

[0003] In industry, Fischer-Tropsch wax refining mainly adopts adsorbent refining method, and the adsorbent used is diatomite, activated clay and the like. In the process of Fischer-Tropsch synthesis wax refining, diatomite and activated clay are mixed in a certain proportion to form a mixed aid for use. The diatomite intercepts the catalyst particles while providing a flow channel for the Fischer-Tropsch wax and providing a skeleton for the attachment, dispersion and support of the activated clay; the addition of activated clay makes the pore of the filter cake layer more conducive to intercepting the ultra-fine particles in the catalyst, and also can adsorb the pigment in the Fischer-Tropsch wax to improve the color of the Fischer-Tropsch wax. Diatomite and clay cannot be reused, and the production cost is high; meanwhile, the waste diatomite and clay containing Fischer-Tropsch wax are hazardous waste, and the disposal cost is high.

[0004] In the prior art, shale ash is used to prepare paraffin wax refining adsorbent, and the shale ash material itself does not have a pore structure and has a low specific surface area, which will result in low adsorption performance of the adsorbent, and most of the adsorbents need to be pretreated, which has a large environmental protection pressure and a complex process and high cost.

[0005] Molecular sieve materials are widely used as catalysts, adsorbents or drying agents in chemical plants. When the catalytic activity of the molecular sieve gradually decreases, the catalyst reaches the end of life and is disposed of as hazardous or general solid waste. Part of the offline molecular sieve still has a regular pore structure and a large specific surface area, and still has certain adsorption performance, and after a certain process treatment, it can be used as a refining adsorbent to realize the resource utilization of "waste to treasure" in industrial devices.

[0006] Patent with publication number CN1195830C provides a paraffin adsorption refining method, which mainly uses diesel oil, lubricating oil distillate oil, and hydrogenation refining waste catalyst of paraffin, and the waste catalyst is treated in a gas medium containing 0.1-20 m% oxygen at 300-600 DEG C for 5-100 hours, as a paraffin refining adsorbent. The waste catalyst treatment process of the method is difficult to control, and the waste catalyst treatment equipment has high requirements and high investment cost.

[0007] Patent with publication number CN112852481A provides a Fischer-Tropsch wax decolorization method, which adds adsorbent A white clay to the molten Fischer-Tropsch wax crude product for first adsorption, then adds adsorbent B for second adsorption to obtain a mixed system, or directly adds adsorbent B to the molten Fischer-Tropsch wax crude product for second adsorption to obtain a mixed system, and then adds separation liquid I to the mixed system under the condition that the Fischer-Tropsch wax crude product is in a molten state, and then performs aging and filtration to obtain refined Fischer-Tropsch wax, separation liquid II and adsorbent. The technology needs multi-stage adsorption and needs to add separation liquid for separation, and needs to be aged and filtered for a long time. The waste catalyst needs to be crushed after calcination and acid and alkali soaking treatment, and the process is complex, and the industrial application potential is low. The waste catalyst is crushed to <50 mesh, and the particle size is too fine to be effectively separated, which causes the ash content in the subsequent product Fischer-Tropsch wax to increase, and the alkali washing of the waste catalyst leads to the content of alkali metal in the Fischer-Tropsch wax exceeding the standard, which affects the product quality.

[0008] Patent with publication number CN105582885B provides a technical solution of a solid adsorbent made of waste molecular sieve catalyst and a preparation method thereof, and the adsorbent is used for adsorption purification of methanol and other oxygen-containing compounds in C2-C6 olefin raw materials. The adsorption material prepared by the method still needs to be pretreated and used after secondary molding, and the process is complex and the cost is high.

[0009] At present, the resource utilization technology of waste molecular sieve mainly uses the silicon aluminum components as raw materials to prepare desulfurizing agent, aluminum sulfate, ultrafine aluminum oxide, or focuses on the recycling technology of metals in waste molecular sieve. However, these technologies have complex treatment and preparation processes of waste molecular sieve, low utilization rate of waste molecular sieve, and are not easy to produce and prepare on a large scale, and the investment and operation are high in large-scale application. Therefore, it is urgent to solve the problems of expanding the efficient, clean and resource utilization way of waste molecular sieve and optimizing the process technology route. SUMMARY

[0010] The main purpose of the present application is to provide a Fischer-Tropsch wax refining method and a Fischer-Tropsch wax product, so as to solve the problems of high cost, poor product quality in the prior art, and large consumption of white clay and diatomite in the Fischer-Tropsch wax filtration unit of the industrial production device, low filtration efficiency and short running time.

[0011] In order to achieve the above object, according to one aspect of the present application, there is provided a Fischer-Tropsch wax refining method, which comprises: step S1, coating a first pre-coating liquid on a filtering device to form a first filter cake, the first pre-coating liquid comprising a first adsorbent and a dispersant, the particle size of the first adsorbent being 50-150 μm; step S2, coating a second pre-coating liquid on the surface of the first filter cake to form a second filter cake, thereby obtaining a pre-coating filter layer, the second pre-coating liquid comprising a second adsorbent and a dispersant, the particle size of the second adsorbent being less than 50 μm; and step S3, filtering the Fischer-Tropsch wax to be treated through the pre-coating filter layer to obtain a qualified Fischer-Tropsch wax product and a waxy waste residue.

[0012] Further, the first adsorbent and the second adsorbent are molecular sieves.

[0013] Preferably, the decolorization rate of the first adsorbent and / or the second adsorbent is ≥ 95%, the activity is ≥ 150 H + mmol / kg, the sodium ion content is ≤ 0.7 wt%, the free acid content is ≤ 0.2 wt%, the heavy metal (calculated as Pb) content is ≤ 0.005 wt%, and the arsenic (calculated as As) content is ≤ 0.0005 wt%.

[0014] Preferably, the first adsorbent and / or the second adsorbent is obtained by calcining and crushing and screening a waste molecular sieve.

[0015] Further, the waste molecular sieve comprises a methanol-to-olefin molecular sieve waste catalyst, a waste 3A adsorbent, a waste 5A adsorbent, and a waste molecular sieve drying agent. 2 Preferably, the specific surface area of the waste molecular sieve is 150-600 m 3 / g, the pore volume is 0.1-0.5 cm

[0016] Preferably, the calcination temperature is 350-600 °C, the calcination time is 10-24 h, the water content in the calcined waste molecular sieve is 4-8 wt%, and the carbon deposition content is ≤ 10 wt%.

[0017] Preferably, the crushing and screening comprises: crushing the calcined waste molecular sieve to obtain a first powder, and screening the first powder to obtain the first adsorbent with a particle size of 50-150 μm and the second adsorbent with a particle size less than 50 μm.

[0018] Further, the dispersant comprises any one or more of heavy wax and Fischer-Tropsch refined wax.

[0019] Preferably, the solid content of the first pre-coating liquid and / or the second pre-coating liquid is 2 wt%-5 wt%.

[0020] Preferably, the mass ratio of the first pre-coating liquid to the second pre-coating liquid is 4:1 to 2:1.

[0021] Further, the first pre-coating liquid comprises, in parts by weight, 60 to 90 parts of the first adsorbent, 0 to 30 parts of the white clay, and 10 to 40 parts of the diatomite.

[0022] Further, the second pre-coating liquid comprises, in parts by weight, 60 to 90 parts of the second adsorbent, 0 to 30 parts of the white clay, and 10 to 40 parts of the diatomite.

[0023] Further, the thickness of the first filter cake is 3 to 5 cm.

[0024] Preferably, in the step S1, the cycle time of the coating is 10 to 30 min.

[0025] Further, the thickness of the second filter cake is 0.5 to 1 cm.

[0026] Preferably, in the step S1, the cycle time of the coating is 5 to 10 min.

[0027] Further, the filtering device is a vane disc filter or a reduced pressure filtering device.

[0028] Preferably, in the step S3, the temperature of the filtering is 160 to 190 ℃, and the pressure is 0 to 0.4 MPa.

[0029] Further, the wax-containing waste residue contains 20wt% to 60wt% of the wax oil; preferably, the wax-containing waste residue is incinerated, and the heat generated by the incineration is utilized.

[0030] According to another aspect of the present application, a Fischer-Tropsch wax product is provided, which is prepared by any one of the above Fischer-Tropsch wax refining methods.

[0031] By applying the technical solution of the present application, the Fischer-Tropsch wax is filtered by twice coating, the filter cake layer formed by coating adsorbents with different particle sizes improves the adsorption performance of the Fischer-Tropsch wax refining adsorbent, the removal efficiency of impurity elements is high, and the quality of the qualified wax product is significantly improved; the wax-containing waste residue generated after the filtering can be incinerated as fuel to provide heat, which not only improves the utilization rate of resources, but also reduces the environmental protection pressure; and the process technical route is simple, easy for industrial production, low in operation cost, and high in economic benefit. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the specification explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0033] Figure 1 A flow chart of a Fischer-Tropsch wax refining method according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0034] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0035] As analyzed in the background of the present application, there is a problem of high cost and poor product quality in the prior art Fischer-Tropsch wax refining process. In order to solve this problem, the present application provides a Fischer-Tropsch wax refining method and a Fischer-Tropsch wax product.

[0036] According to a typical embodiment of the present application, a Fischer-Tropsch wax refining method is provided, which comprises: step S1, coating a first pre-coating liquid on a filtering device to form a first filter cake, the first pre-coating liquid comprising a first adsorbent and a dispersant, the particle size of the first adsorbent being 50-150 μm; step S2, coating a second pre-coating liquid on the surface of the first filter cake to form a second filter cake, thereby obtaining a pre-coated filter layer, the second pre-coating liquid comprising a second adsorbent and a dispersant, the particle size of the second adsorbent being less than 50 μm; and step S3, filtering the to-be-processed Fischer-Tropsch wax through the pre-coated filter layer to obtain a qualified Fischer-Tropsch wax product and a wax-containing waste residue.

[0037] The present application adopts a twice-coating method to pre-coat and filter the Fischer-Tropsch wax, and the filter cake layers formed by coating adsorbents with different particle sizes improve the adsorption performance of the Fischer-Tropsch wax refining adsorbent, the impurity element removal efficiency is high, and the quality of the qualified wax product is significantly improved. The wax-containing waste residue produced after filtering can be incinerated as fuel to provide heat, which not only improves the utilization rate of resources, but also reduces the environmental protection pressure. Moreover, the process technical route is simple, easy to industrialize, low in operation cost, and high in economic benefit.

[0038] The first adsorbent and the second adsorbent with different particle size distributions described above can be obtained by sieving through a screen with a corresponding pore size.

[0039] In some embodiments of the present application, the first adsorbent and the second adsorbent each independently comprise any one or more of a molecular sieve, a 3A type adsorbent, a 5A type adsorbent, and a drying agent, which has a high adsorption efficiency for impurities such as iron catalysts that are difficult to separate from the Fischer-Tropsch wax.

[0040] In order to further improve the quality of the refined Fischer-Tropsch wax, in some preferred embodiments of the present application, the decolorization rate of the first adsorbent and / or the second adsorbent is ≥95%, the activity is ≥150 H +mmol / kg, sodium ion content ≤0.7wt%, free acid content ≤0.2wt%, heavy metal (in terms of Pb) ≤0.005wt%, arsenic (in terms of As) ≤0.0005wt%.

[0041] In some typical embodiments of the present application, in order to further reduce the refining cost of Fischer-Tropsch wax, the first adsorbent and / or the second adsorbent is obtained by calcination and crushing and screening treatment of waste molecular sieve. The source of the waste molecular sieve is not limited, including but not limited to waste methanol-to-olefin molecular sieve catalyst, waste 3A adsorbent, waste 5A adsorbent and waste molecular sieve drying agent. For the waste molecular sieve, the waste molecular sieve mainly composed of silicon aluminum has the physical characteristics of developed pores and high specific surface area. The resource utilization of the waste molecular sieve is applied to refine Fischer-Tropsch wax, replaces the traditional industrial clay, adsorbs and retains the impurities such as iron catalyst in Fischer-Tropsch wax, improves the adsorption efficiency, and improves the quality of qualified wax products. At the same time, the recycling of the existing waste molecular sieve is solved, the efficient, clean and comprehensive utilization of the waste molecular sieve resource is realized, and certain economic benefits are brought to the enterprise.

[0042] In order to further improve the performance of the first adsorbent and / or the second adsorbent obtained by calcination and crushing and screening treatment, and improve the refining effect of Fischer-Tropsch wax, in some embodiments of the present application, the specific surface area of the waste molecular sieve is 150-600 m 2 / g, the pore volume is 0.1-0.5 cm 3 / g, the free alkali metal content is ≤0.7wt%, the free nitrogen oxide content is ≤0.5wt%, and the sulfur oxide content is ≤0.3wt%.

[0043] In some embodiments of the present application, when the above waste molecular sieve is calcined, the calcination temperature is 350-600°C, preferably, the calcination time is 10-24h, which is beneficial to maintain the morphology of the waste molecular sieve, and at the same time, the water and carbon deposition impurities in the waste molecular sieve are removed more efficiently, which is beneficial to improve the adsorption performance. Preferably, the water content in the calcined waste molecular sieve is 4-8wt%, and the carbon deposition content is ≤10wt%.

[0044] In some embodiments of the present application, the above crushing and screening includes: crushing the calcined waste molecular sieve to obtain a first powder, and obtaining the first adsorbent or the second adsorbent which can be applied to the Fischer-Tropsch wax refining method of the present application. In order to further improve the treatment efficiency, the first powder is screened to obtain a powder with a particle size of 50-150μm, which is used in the first pre-coating liquid of the present application as the first adsorbent, and the powder with a particle size less than 50μm is used in the second pre-coating liquid of the present application as the second adsorbent.

[0045] The dispersing agent is added in the first pre-coating liquid and the second pre-coating liquid to facilitate uniform dispersion of the adsorbent and form a stable and uniform filter cake. In some embodiments of the present application, the dispersing agent includes any one or more of heavy wax and Fischer-Tropsch refined wax, so as to prevent introduction of new impurities in the filter cake during the filtration process.

[0046] In some embodiments of the present application, the solid content of the first pre-coating liquid and / or the second pre-coating liquid is 2wt% to 5wt%, and the adsorption filtration effect of the pre-coating filter device formed is better.

[0047] In some preferred embodiments of the present application, the mass ratio of the first pre-coating liquid to the second pre-coating liquid is 4:1 to 2:1, and the pre-coating filter layer formed can further improve the adsorption capacity for impurities and improve the quality of qualified Fischer-Tropsch wax.

[0048] In some typical embodiments of the present application, the first pre-coating liquid includes, in parts by weight, 60 to 90 parts of the first adsorbent, 0 to 30 parts of the clay, and 10 to 40 parts of the diatomite; and / or the second pre-coating liquid includes, in parts by weight, 60 to 90 parts of the second adsorbent, 0 to 30 parts of the clay, and 10 to 40 parts of the diatomite. By mixing the adsorbent with the diatomite or the clay, the synergistic effect can be further exerted to improve the refining effect of the Fischer-Tropsch wax. At the same time, the problems of large consumption of the clay and the diatomite, high unit consumption, low filtration efficiency, and short running time of the Fischer-Tropsch wax filtration unit in the current industrial production device are solved.

[0049] In some embodiments of the present application, the thickness of the first filter cake is 3 to 5 cm, which is conducive to improving the refining effect of the Fischer-Tropsch wax; preferably, in step S1, the cycle time of the coating is 10 to 30 minutes, and the filter cake formed is more uniform and has a more suitable porosity.

[0050] In order to further improve the refining effect of the Fischer-Tropsch wax, in some embodiments of the present application, the thickness of the second filter cake is 0.5 to 1 cm; preferably, in step S1, the cycle time of the coating is 5 to 10 minutes.

[0051] The filter device can be selected from the prior art, such as a vane disc filter or a reduced pressure filtration device.

[0052] In some preferred embodiments of the present application, in step S3, the filtration temperature is 160 to 190°C, and the pressure is 0 to 0.4 MPa, which can further improve the quality and refining efficiency of the Fischer-Tropsch wax.

[0053] By the method of the present application, the qualified Fischer-Tropsch wax can be obtained after filtration. The filter cake layer formed in the filtration device is a solid waste containing solid impurities (iron catalyst, etc.), adsorbent, clay, diatomite and 20-60% wax oil. Preferably, the wax-containing waste is incinerated, and the heat generated by incineration is utilized. In some preferred embodiments of the present application, the above-mentioned wax-containing waste is incinerated in a three-waste furnace, and the hot flue gas generated is used for the calcination treatment of the waste molecular sieve. The tail gas is treated by conventional environmental protection equipment and then discharged.

[0054] In some typical embodiments of the present application, the Fischer-Tropsch wax refining method is as shown in Figure 1 The waste molecular sieve is calcined and then crushed and sieved to prepare Fischer-Tropsch wax refining adsorbent with a particle size of 50-150 μm and a particle size of less than 50 μm. The first pre-coating liquid containing Fischer-Tropsch wax refining adsorbent with a particle size of 50-150 μm is pre-coated once, and the second pre-coating liquid containing Fischer-Tropsch wax refining adsorbent with a particle size of less than 50 μm is pre-coated twice on the surface of the filter cake formed by the first pre-coating to form a pre-coated filter layer. The Fischer-Tropsch synthetic wax to be treated is filtered through the pre-coated filter layer, and the filtrate is the qualified Fischer-Tropsch wax. The filtration device discharges the residue, and the wax-containing residue is collected and incinerated. The heat provided by the incineration is used for the calcination process of the waste molecular sieve. This method uses waste molecular sieve to prepare Fischer-Tropsch wax refining adsorbent, and the waste residue generated after filtration is used to provide heat for the calcination of the waste molecular sieve, which not only improves the utilization rate of resources, but also solves the environmental pressure of treating waste molecular sieve as hazardous waste or general solid waste.

[0055] According to another typical embodiment of the present application, a Fischer-Tropsch wax product is provided, which is prepared by any of the above-mentioned Fischer-Tropsch wax refining methods.

[0056] The Fischer-Tropsch wax product prepared by the above-mentioned method not only has low metal impurity content, good quality and low cost, but also has good market prospects.

[0057] The beneficial effects that can be achieved by the present application will be further illustrated below with examples and comparative examples.

[0058] Example 1

[0059] ZSM-5 type waste MTP molecular sieve is selected, the calcination temperature is 550°C, the calcination time is 16 hours, and the fine powder with a particle size of 50-150 μm and the fine powder with a particle size of less than 50 μm are obtained after crushing and sieving. The technical parameters of the above-mentioned fine powder are shown in Table 1, wherein the fine powder with a particle size of less than 50 μm accounts for 5.6wt%.

[0060] Take 80 parts of the above fine powder with particle size of 50-150 μm, 10 parts of white clay, 10 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid A with solid content of 4%; take 80 parts of the above fine powder with particle size less than 50 μm, 10 parts of white clay, 10 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid B with solid content of 4%.

[0061] First, 150 g of the above pre-coating liquid A is pre-coated on a blade disc filter to form a first layer filter cake with thickness of 3.5 cm, and the pre-coating cycle is 15 min; then, 50 g of the above pre-coating liquid B is pre-coated on the first layer filter cake to form a second layer filter cake with thickness of 0.6 cm, and the pre-coating cycle is 5 min. Take 90 g of Fischer-Tropsch wax raw material and heat it to 80℃ until it is completely melted, and then pour the Fischer-Tropsch wax into the pre-coating layer formed by the refining agent under the experimental conditions of pressure of 0.25 MPa and temperature of 180℃, collect the qualified wax sample after filtration, and the properties are shown in Table 2.

[0062] Example 2

[0063] Select ZSM-5 type waste MTP molecular sieve, calcination temperature 450℃, calcination for 12 hours, crushing and sieving to obtain fine powder with particle size of 50-150 μm and fine powder with particle size less than 50 μm. The technical parameters of the above fine powder are shown in Table 1, wherein the fine powder with particle size less than 50 μm accounts for 4.2wt%.

[0064] Take 70 parts of the above fine powder with particle size of 50-150 μm, 10 parts of white clay, 20 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid A with solid content of 3%; take 70 parts of the above fine powder with particle size less than 50 μm, 10 parts of white clay, 20 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid B with solid content of 3%.

[0065] First, 150 g of the above pre-coating liquid A is pre-coated on a blade disc filter to form a first layer filter cake with thickness of 4 cm, and the pre-coating cycle is 20 min; then, 50 g of the above pre-coating liquid B is pre-coated on the first layer filter cake to form a second layer filter cake with thickness of 0.5 cm, and the pre-coating cycle is 5 min. Take 90 g of Fischer-Tropsch wax raw material and heat it to 80℃ until it is completely melted, and then pour the Fischer-Tropsch wax into the pre-coating layer formed by the refining agent under the experimental conditions of pressure of 0.21 MPa and temperature of 185℃, collect the qualified wax sample after filtration, and the properties are shown in Table 2.

[0066] Example 3

[0067] Select ZSM-5 type waste MTP molecular sieve, calcination temperature 450℃, calcination for 14 hours, crushing and sieving to obtain fine powder with particle size of 50-150 μm and fine powder with particle size less than 50 μm. The technical parameters of the above fine powder are shown in Table 1, wherein the fine powder with particle size less than 50 μm accounts for 6.5wt%.

[0068] Take 70 parts of the above fine powder with particle size of 50-150 μm, 30 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid A with solid content of 3%; take 70 parts of the above fine powder with particle size less than 50 μm, 30 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid B with solid content of 3%.

[0069] First, 150 g of the above pre-coating liquid A is pre-coated on a blade disc filter to form a first layer filter cake with thickness of 3 cm, and the pre-coating cycle is 15 min; then, 50 g of the pre-coating liquid B is pre-coated on the first layer filter cake to form a second layer filter cake with thickness of 0.6 cm, and the pre-coating cycle is 8 min. Take 90 g of the fischer-tropsch wax raw material to heat to 80℃ until it is completely melted, and under the experimental conditions of pressure of 0.22 MPa and temperature of 185℃, pour the fischer-tropsch wax into the pre-coating layer formed by the refining agent, collect the qualified wax sample after filtration, and the properties are shown in Table 2.

[0070] Example 4

[0071] Select 3A type adsorbent, calcination temperature 500℃, calcination for 12 hours, crush and sieve to obtain fine powder with particle size of 50-150 μm and fine powder with particle size less than 50 μm. The technical parameters of the above fine powder are shown in Table 1, wherein the fine powder with particle size less than 50 μm accounts for 7.5wt%.

[0072] Take 60 parts of the above fine powder with particle size of 50-150 μm, 20 parts of white clay, and 20 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid A with solid content of 4%; take 60 parts of the above fine powder with particle size less than 50 μm, 20 parts of white clay, and 20 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid B with solid content of 4%.

[0073] First, 150 g of the above pre-coating liquid A is pre-coated on a blade disc filter to form a first layer filter cake with thickness of 3.2 cm, and the pre-coating cycle is 15 min; then, 50 g of the pre-coating liquid B is pre-coated on the first layer filter cake to form a second layer filter cake with thickness of 0.8 cm, and the pre-coating cycle is 10 min. Take 90 g of the fischer-tropsch wax raw material to heat to 80℃ until it is completely melted, and under the experimental conditions of pressure of 0.27 MPa and temperature of 175℃, pour the fischer-tropsch wax into the pre-coating layer formed by the refining agent, collect the qualified wax sample after filtration, and the properties are shown in Table 2.

[0074] Example 5

[0075] Select 5A type adsorbent, calcination temperature 450℃, calcination for 10 hours, crush and sieve to obtain fine powder with particle size of 50-150 μm and fine powder with particle size less than 50 μm. The technical parameters of the above fine powder are shown in Table 1, wherein the fine powder with particle size less than 50 μm accounts for 5.8wt%.

[0076] Take 70 parts of the above-mentioned fine powder with particle size of 50-150 μm, 20 parts of white clay, 10 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid A with solid content of 5%; take 70 parts of the above-mentioned fine powder with particle size less than 50 μm, 20 parts of white clay, 10 parts of diatomite to mix, and mix with stable heavy wax to form a uniform pre-coating liquid B with solid content of 5%.

[0077] First, 150 g of the above-mentioned pre-coating liquid A is pre-coated on a blade disc filter to form a first layer of filter cake with thickness of 4.3 cm, and the pre-coating cycle is 25 min; then, 50 g of the pre-coating liquid B is pre-coated on the first layer of filter cake to form a second layer of filter cake with thickness of 0.6 cm, and the pre-coating cycle is 5 min. Take 90 g of the Fischer-Tropsch wax raw material to heat to 80 °C until it is completely melted, and under the experimental conditions of pressure of 0.23 MPa and temperature of 165 °C, pour the Fischer-Tropsch wax into the pre-coating layer formed by the refining agent, collect the qualified wax sample after filtration, and the properties are shown in Table 2.

[0078] Comparative Example 1

[0079] Take 75 parts of white clay and 25 parts of diatomite to prepare a refining adsorbent, and the technical parameters of the refining adsorbent are shown in Table 1. Mix 200 g of the above-mentioned Fischer-Tropsch wax refining adsorbent with stable heavy wax to form a uniform pre-coating liquid with concentration of 3%, and pre-coat it on a blade disc filter to form a stable filter cake layer with thickness of 3.5 cm. Take 90 g of the Fischer-Tropsch wax raw material to heat to 80 °C until it is completely melted, and under the experimental conditions of pressure of 0.25 MPa and temperature of 180 °C, pour the Fischer-Tropsch wax into the pre-coating layer formed by the refining agent, collect the qualified wax sample after filtration, and the properties are shown in Table 2.

[0080] Comparative Example 2

[0081] Take 60 parts of white clay and 40 parts of diatomite to prepare a refining adsorbent, and the technical parameters of the refining adsorbent are shown in Table 1. Mix 200 g of the above-mentioned Fischer-Tropsch wax refining adsorbent with stable heavy wax to form a uniform pre-coating liquid with concentration of 4%, and pre-coat it on a blade disc filter to form a stable filter cake layer with thickness of 4.2 cm. Take 90 g of the Fischer-Tropsch wax raw material to heat to 80 °C until it is completely melted, and under the experimental conditions of pressure of 0.20 MPa and temperature of 180 °C, pour the Fischer-Tropsch wax into the pre-coating layer formed by the refining agent, collect the qualified wax sample after filtration, and the properties are shown in Table 2.

[0082] Comparative Example 3

[0083] Take 80 parts of the same powder with particle size of 50-150 μm as in Example 1, 10 parts of white clay, and 10 parts of diatomite to prepare a refining adsorbent.

[0084] The above-mentioned refined adsorbent was mixed with the stable heavy wax to form a uniform pre-coating liquid with a concentration of 4%, and 200 g was pre-coated on a vane disc filter to form a stable filter cake layer with a thickness of 4.2 cm. 90 g of the F-T wax raw material was heated to 80°C until it was completely melted, and then poured into the pre-coating layer formed by the refined agent under the experimental conditions of a pressure of 0.20 MPa and a temperature of 180°C. The qualified wax sample after filtration was collected, and the properties are shown in Table 2.

[0085] Comparative Example 4

[0086] The ZSM-5 type waste MTP molecular sieve was selected, the calcination temperature was 550°C, the calcination time was 16 hours, and the fine powder with a particle size of less than 150 μm was obtained after crushing and sieving. The fine powder with a particle size of less than 50 μm accounted for 5.6 wt%. 80 parts of the above-mentioned fine powder with a particle size of less than 150 μm, 10 parts of the white clay, and 10 parts of the diatomite were mixed to prepare the refined adsorbent.

[0087] The above-mentioned refined adsorbent was mixed with the stable heavy wax to form a uniform pre-coating liquid with a concentration of 4%, and 200 g was pre-coated on a vane disc filter to form a stable filter cake layer with a thickness of 4.2 cm. 90 g of the F-T wax raw material was heated to 80°C until it was completely melted, and then poured into the pre-coating layer formed by the refined agent under the experimental conditions of a pressure of 0.20 MPa and a temperature of 180°C. The qualified wax sample after filtration was collected, and the properties are shown in Table 2.

[0088] Comparative Example 5

[0089] The ZSM-5 type waste MTP molecular sieve was selected, the calcination temperature was 550°C, the calcination time was 16 hours, and the fine powder with a particle size of less than 150 μm was obtained after crushing and sieving. The fine powder with a particle size of less than 50 μm accounted for 5.6 wt%. 80 parts of the above-mentioned fine powder with a particle size of less than 150 μm, 10 parts of the white clay, and 10 parts of the diatomite were mixed to prepare the refined adsorbent.

[0090] 80 parts of the above-mentioned fine powder with a particle size of 100-200 μm, 10 parts of the white clay, and 10 parts of the diatomite were mixed to form a uniform pre-coating liquid A with a solid content of 4% by mixing with the stable heavy wax; 80 parts of the above-mentioned fine powder with a particle size of less than 100 μm, 10 parts of the white clay, and 10 parts of the diatomite were mixed to form a uniform pre-coating liquid B with a solid content of 4% by mixing with the stable heavy wax.

[0091] 150 g of the above-mentioned pre-coating liquid A was pre-coated on a vane disc filter to form a first layer filter cake with a thickness of 4.0 cm, and the pre-coating cycle was 15 min; 50 g of the above-mentioned pre-coating liquid B was pre-coated on the first layer filter cake to form a second layer filter cake with a thickness of 0.9 cm, and the pre-coating cycle was 5 min. 90 g of the F-T wax raw material was heated to 80°C until it was completely melted, and then poured into the pre-coating layer formed by the refined agent under the experimental conditions of a pressure of 0.25 MPa and a temperature of 180°C. The qualified wax sample after filtration was collected, and the properties are shown in Table 2.

[0092] Comparative Example 6

[0093] ZSM-5 type waste MTP molecular sieve was selected, the calcination temperature was 550℃, the calcination time was 16 hours, and the fine powder with a particle size of 100-150μm and the fine powder with a particle size less than 100μm were obtained by crushing and sieving, and the technical parameters were the same as those in Example 1.

[0094] 80 parts of the fine powder with a particle size of 100-150μm, 10 parts of the white clay and 10 parts of the diatomite were mixed to form a uniform pre-coating liquid A with a solid content of 4% by mixing with the stable heavy wax; 80 parts of the fine powder with a particle size less than 100μm, 10 parts of the white clay and 10 parts of the diatomite were mixed to form a uniform pre-coating liquid B with a solid content of 4% by mixing with the stable heavy wax.

[0095] 150g of the pre-coating liquid A was pre-coated on the blade disc filter to form a first layer filter cake with a thickness of 3.7cm, and the pre-coating cycle was 15min; 50g of the pre-coating liquid B was pre-coated on the first layer filter cake to form a second layer filter cake with a thickness of 0.8cm, and the pre-coating cycle was 5min. 90g of the fischer-tropsch wax raw material was heated to 80℃ until it was completely melted, and under the experimental conditions of a pressure of 0.25MPa and a temperature of 180℃, the fischer-tropsch wax was poured into the pre-coating layer formed by the refining agent, and the qualified wax sample after filtration was collected, and the properties were shown in Table 2.

[0096] Table 1

[0097]

[0098]

[0099] Table 2

[0100]

[0101] From the above description, it can be seen that the above-mentioned examples of the present application achieve the following technical effects: the pre-coating filtration of the fischer-tropsch wax is carried out in a two-time coating manner, the filter cake layer formed by coating the adsorbents with different particle sizes improves the adsorption performance of the fischer-tropsch wax refining adsorbent, the impurity element removal efficiency is high, and the quality of the qualified wax product is significantly improved; and the process technical route is simple, easy for industrial production, low in operation cost and high in economic benefit.

[0102] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for the finishing of Fischer-Tropsch waxes, characterized in that, The application relates to a method for preparing a pre-coated filter layer for filtering a Fischer-Tropsch wax, comprising the following steps: S1, applying a first pre-coating liquid on a filter device to form a first filter cake, wherein the first pre-coating liquid comprises a first adsorbent, white clay, diatomite and a dispersant, and the first pre-coating liquid comprises, in parts by weight, 60-90 parts of the first adsorbent, 0-30 parts of the white clay and 10-40 parts of the diatomite, wherein the particle size of the first adsorbent is 50-150 mu m; S2, applying a second pre-coating liquid on the surface of the first filter cake to form a second filter cake, thereby obtaining a pre-coated filter layer, wherein the second pre-coating liquid comprises a second adsorbent, white clay, diatomite and a dispersant, and the second pre-coating liquid comprises, in parts by weight, 60-90 parts of the second adsorbent, 0-30 parts of the white clay and 10-40 parts of the diatomite, wherein the particle size of the second adsorbent is less than 50 mu m; S3, filtering the Fischer-Tropsch wax to be treated through the pre-coated filter layer to obtain qualified Fischer-Tropsch wax products and a wax-containing waste residue. The first adsorbent and the second adsorbent each independently comprise a molecular sieve; the dispersant in the step S1 and the dispersant in the step S2 each independently comprise any one or more of heavy wax and Fischer-Tropsch refined wax. The solid content of the first pre-coating liquid and / or the second pre-coating liquid is 2 wt%-5 wt%. The mass ratio of the first pre-coating liquid to the second pre-coating liquid is 4:1-2:

1. The first adsorbent and the second adsorbent are molecular sieves. The first adsorbent and / or the second adsorbent are obtained by calcining and crushing and screening treatment of waste molecular sieves. The waste molecular sieves comprise methanol-to-olefin molecular sieve waste catalysts.

2. The Fischer-Tropsch wax finishing process according to claim 1, characterized in that, The waste molecular sieves comprise waste 3A adsorbents and / or waste 5A adsorbents.

3. The Fischer-Tropsch wax finishing process according to claim 1, characterized in that, The first adsorbent and / or the second adsorbent have a decolorization rate of > 95%, an activity of > 150 H + mmol / kg, a sodium ion content of < 0.7 wt%, a free acid content of < 0.2 wt%, a heavy metal content of < 0.005 wt% as Pb, and an arsenic content of < 0.0005 wt% as As.

4. The Fischer-Tropsch wax finishing process according to claim 1, characterized in that, The waste molecular sieves comprise waste molecular sieve driers.

5. The Fischer-Tropsch wax finishing process according to claim 4, characterized in that, The calcination temperature is 350-600 DEG C. The crushing and screening comprises crushing the calcined waste molecular sieves to obtain a first powder, and screening the first powder to obtain the first adsorbent with a particle size of 50-150 mu m and the second adsorbent with a particle size of less than 50 mu m.

6. The Fischer-Tropsch wax finishing process according to claim 4, characterized in that, The calcination time is 10-24 h.

7. The Fischer-Tropsch wax finishing process according to claim 5, characterized in that, said spent molecular sieve has a specific surface area of 150 to 600 m 2 / g, a pore volume of 0.1 to 0.5 cm 3 / g, a free alkali metal content of < 0.7 wt%, a free nitrogen oxide content of < 0.5 wt%, a sulfur oxide content of < 0.3 wt%. The water content in the calcined waste molecular sieves is 4-8 wt%, and the carbon deposition content is less than or equal to 10 wt%. The thickness of the first filter cake is 3-5 cm.

8. The Fischer-Tropsch wax finishing process according to claim 7, characterized in that, In the step S1, the cycle time of the coating is 10-30 min.

9. The Fischer-Tropsch wax finishing process according to claim 7, characterised in that, The thickness of the second filter cake is 0.5-1 cm.

10. The Fischer-Tropsch wax finishing process according to any one of claims 1 to 9, characterized in that, In the step S2, the cycle time of the coating is 5-10 min.

11. The Fischer-Tropsch wax finishing process according to claim 10, characterized in that, The filter device is a vane-type disc filter or a reduced-pressure filter device.

12. A Fischer-Tropsch wax finishing process according to any one of claims 1 to 9 characterised in that, In the step S3, the filtering temperature is 160-190 DEG C, and the pressure is 0-0.4 MPa.

13. The Fischer-Tropsch wax finishing process according to claim 12, characterized in that, The wax-containing waste residue contains 20 wt%-60 wt% of wax oil.

14. The Fischer-Tropsch wax finishing process according to any one of claims 1 to 9, characterized in that, The wax-containing waste residue is incinerated, and the heat generated by the incineration is utilized.

15. The Fischer-Tropsch wax finishing process according to claim 14, characterized in that, ​ 16. A Fischer-Tropsch wax finishing process according to any one of claims 1 to 9 characterised in that, ​ 17. The Fischer-Tropsch wax finishing process according to claim 16, characterized in that, ​

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