阅读说明：本技术 从含催化剂蜡渣中回收蜡的回收方法和装置 (Recovery method and device for recovering wax from catalyst-containing wax residue ) 是由 狄清林 黄克旺 张伟 雍晓静 赵铁剑 马丽萍 田茂银 李光琳 蒋艺初 金政伟 于 2020-12-30 设计创作，主要内容包括：本发明涉及费托渣蜡处理领域,公开了一种从含催化剂蜡渣中回收蜡的回收方法和装置。其中,该方法包括：(1)将含催化剂蜡渣用费托自产轻质油进行溶解,制得混合液；(2)将所述混合液与无机提取剂进行混合,得到混合体系；(3)将所述混合体系进行静置分离,得到上层产物、中层产物和下层产物,所述上层产物为费托自产轻质油与含有小于3wt％残留催化剂的蜡的混合物,所述中层产物为无机提取剂,所述下层产物为含有小于3wt％残留蜡的催化剂；对所述上层产物进行回收；其中,所述含催化剂蜡渣包括费托渣蜡和/或渣蜡残渣,所述渣蜡残渣为费托渣蜡经粗过滤后所得的产物。可实现不引入系统外有机杂质,不影响回收蜡的品质,无机提取剂可回收重复利用。(The invention relates to the field of Fischer-Tropsch wax residue treatment, and discloses a method and a device for recovering wax from catalyst-containing wax residue. Wherein, the method comprises the following steps: (1) dissolving catalyst-containing wax residue with Fischer-Tropsch produced light oil to obtain a mixed solution; (2) mixing the mixed solution with an inorganic extractant to obtain a mixed system; (3) standing and separating the mixed system to obtain an upper layer product, a middle layer product and a lower layer product, wherein the upper layer product is a mixture of Fischer-Tropsch self-produced light oil and wax containing less than 3 wt% of residual catalyst, the middle layer product is an inorganic extractant, and the lower layer product is a catalyst containing less than 3 wt% of residual wax; recovering the upper layer product; the catalyst-containing wax residue comprises Fischer-Tropsch wax residue and/or wax residue, and the wax residue is a product obtained by coarsely filtering Fischer-Tropsch wax residue. The method can realize that organic impurities outside the system are not introduced, the quality of the recovered wax is not influenced, and the inorganic extracting agent can be recycled.)

1. A method for recovering wax from catalyst-containing wax residue, the method comprising:

(1) dissolving catalyst-containing wax residue with Fischer-Tropsch produced light oil to obtain a mixed solution;

(2) mixing the mixed solution with an inorganic extractant to obtain a mixed system;

(3) standing and separating the mixed system to obtain an upper layer product, a middle layer product and a lower layer product, wherein the upper layer product is a mixture of Fischer-Tropsch self-produced light oil and wax containing less than 3 wt% of residual catalyst, the middle layer product is an inorganic extractant, and the lower layer product is a catalyst containing less than 3 wt% of residual wax; recovering the upper layer product;

the catalyst-containing wax residue comprises Fischer-Tropsch wax residue and/or wax residue, and the wax residue is a product obtained by coarsely filtering Fischer-Tropsch wax residue.

2. The method of claim 1, wherein the conditions of dissolution comprise: the dissolving temperature is 65-100 ℃, and the dissolving time is 0.5-5 h;

preferably, the dissolution is carried out under stirring at a rate of from 15 to 100 rpm.

3. The process according to claim 1 or 2, wherein, in step (1), the catalyst-containing wax residue: the mass ratio of the Fischer-Tropsch self-produced light oil is 1: (2-8).

4. The process of any one of claims 1 to 3, wherein in step (1), the Fischer-Tropsch light oil is a C8-C16 hydrocarbon compound.

5. The method according to any one of claims 1 to 4, wherein in step (2), the conditions of the mixing comprise: the mixing temperature is 70-100 ℃, the mixing time is 0.5-5h, the mixing is carried out under the stirring condition, and the mixing stirring speed is 20-100 r/m.

6. The method according to any one of claims 1 to 5, wherein, in step (2), the mixed liquor: the volume ratio of the inorganic extractant is (0.5-4) to 1.

7. The process according to any one of claims 1 to 6, wherein, in step (2), the inorganic extractant is an aqueous basic inorganic compound solution.

8. The method according to claim 7, wherein the solute of the aqueous alkaline inorganic compound solution is an inorganic base and/or an alkaline inorganic salt, preferably NaOH, Na₂CO₃、KOH、K₂CO₃One or more of;

preferably, the pH of the aqueous solution of the basic inorganic compound is 8 to 13.

9. An apparatus for recovering wax from catalyst-containing wax residue, the apparatus comprising: an extractant circulating tank (T-1), a wax residue dissolving tank (T-2), a separating tank (T-3), a filter press (F-1), an extractant circulating pump (P-1), a wax residue feeding pump (P-2) and a wax extraction pump (P-3); wherein the content of the first and second substances,

the extractant circulating pump (P-1) is communicated with the extractant circulating tank (T-1) and the separating tank (T-3) and is used for conveying the inorganic extractant in the extractant circulating tank (T-1) to the separating tank (T-3) through the extractant circulating pump (P-1); the wax residue dissolving tank (T-2) is used for dissolving the catalyst-containing wax residue and the Fischer-Tropsch self-produced light oil into a mixed solution; the wax residue feeding pump (P-2) is communicated with the wax residue dissolving tank (T-2) and the separating tank (T-3) and is used for conveying the mixed liquid into the separating tank (T-3); the separation tank (T-3) is used for mixing the mixed solution with the inorganic extractant and standing for separation to obtain an upper-layer product, a middle-layer product and a lower-layer product; the wax extraction pump (P-3) is communicated with the upper part of the separation tank (T-3) and is used for recovering and conveying the upper-layer product to a wax filtering system, and qualified wax liquid is obtained through fine filtration and separation; the filter press (F-1) is communicated with the bottom of the separation tank (T-3) and the extractant circulating tank (T-1) and is used for carrying out filter pressing on the middle-layer product and the lower-layer product to obtain a solid-phase filter cake for solid waste treatment, and the obtained liquid phase is returned to the extractant circulating tank (T-1) for recycling.

10. A process for fischer-tropsch synthesis, the process comprising:

(A) performing Fischer-Tropsch synthesis reaction on coal-based synthesis gas in a slurry bed reactor in the presence of a catalyst to obtain a Fischer-Tropsch synthesis product, generating Fischer-Tropsch wax containing the catalyst when the catalyst is replaced by the slurry bed reactor, and dividing the Fischer-Tropsch wax into a Fischer-Tropsch wax and b Fischer-Tropsch wax;

(B) carrying out coarse filtration and separation on the a strand of Fischer-Tropsch wax residues to obtain wax residue and wax liquid;

(C) carrying out the recovery method of any one of claims 1 to 8 on the b-strand Fischer-Tropsch wax residue and/or the residue wax residue as catalyst-containing wax residue, and carrying out fine filtration and separation on an upper-layer product obtained by the recovery method and the wax liquid to obtain qualified wax liquid;

(D) carrying out vacuum rectification on the qualified wax liquid to obtain Fischer-Tropsch self-produced light oil, heavy oil and diesel oil;

wherein the Fischer-Tropsch produced light oil is returned to step (C) for use in the recovery process.

Technical Field

The invention relates to the field of Fischer-Tropsch wax residue treatment, in particular to a method and a device for recovering wax from catalyst-containing wax residue.

Background

The Fischer-Tropsch reaction (Fischer-Tropsch synthesis) is the main reaction of coal indirect liquefaction, and the process is mainly characterized in that coal-based synthesis gas is used as a raw material in a slurry bed reactor to synthesize liquid fuels such as light hydrocarbon, heavy wax and the like under a catalyst and proper reaction conditions. In the process of replacing the catalyst on line in the slurry bed reactor, a large amount of wax residue containing the catalyst is discharged, and a filter cake formed after filtration is treated by solid waste. Because the catalyst-containing wax residue contains a large amount of Fischer-Tropsch catalyst which is wrapped by wax and has certain activity, the Fischer-Tropsch catalyst is easy to store heat and spontaneously ignite when exposed in the air, thereby causing potential safety hazard. For a long time, the wax and the catalyst can not be effectively separated, the wax residue containing the catalyst can only be used as dangerous solid waste to be incinerated and then buried for treatment, and the wax in the wax can not be effectively recovered, thereby causing resource waste and environmental problems.

CN110387261A discloses a processing device and a processing method of Fischer-Tropsch wax, and the method comprises the following steps: (1) contacting the wax residue with an organic solvent for extraction; (2) carrying out solid-liquid separation on the mixed solution obtained in the step (1) to obtain a separation solution and a separation solid phase; (3) recovering the surface liquid phase residue of the separated solid phase; (4) carrying out reduced pressure rectification on the separation liquid and the recovered surface liquid phase residue of the separated solid phase to obtain finished wax; the extraction conditions include: the temperature is 40-110 ℃ under a standard atmospheric pressure. The method firstly separates solid-phase catalyst residues by using an organic solvent extraction mode, and then carries out reduced pressure rectification on an extraction liquid phase to obtain the finished wax. The method needs to add a subsequent separation process to separate the organic solvent and the wax, and cannot fully utilize the device conditions of the existing Fischer-Tropsch synthesis and separation process.

CN201810619832 discloses a resource recycling method of Fischer-Tropsch wax, which comprises the following steps: (1) mixing Fischer-Tropsch wax residue with a No. 1 extracting agent, extracting at 50-300 ℃, and then carrying out solid-liquid separation to obtain a mixed solution and solid residues; (2) heating the mixed solution to evaporate the No. 1 extractant and separate the extractant from paraffin; (3) soaking and washing the solid residue by using a No. 2 extracting agent, and then carrying out solid-liquid separation to obtain a catalyst with a passivated surface; wherein the 1# extractant is a hydrocarbon extractant which has a molecular structure of C_nH_2n、C_nH_2n+2 or C_nH_2n-6N is not less than 6; the 2# extractant is the 1# extractant or the mixture of the 1# extractant and the passivating agent. The method has high extraction temperature and additional energy consumption caused by evaporation separation.

CN110016364 discloses a treatment device and a treatment process for Fischer-Tropsch wax residue, and the process comprises the following steps: (1) filtering the wax residue to obtain a first wax residue and heavy wax, and recovering the heavy wax; (2) extracting the first wax residue by using an extraction solvent to obtain a second wax residue and a second liquid phase material flow containing the extraction solvent and heavy wax; (3) and separating the second liquid phase material flow to obtain heavy wax and an extraction solvent, and respectively recovering the heavy wax and the extraction solvent. The extraction solvent benzene or xylene used by the method can cause doping pollution to Fischer-Tropsch reaction products in the existing production device and influence the product quality.

In conclusion, the research method adopts the organic solvent for extraction, introduces external organic impurities into the Fischer-Tropsch synthesis separation system to influence the quality of the product, and has the disadvantages of difficult recycling of the organic solvent and great increase of the use cost. In addition, the extraction and separation temperature is high, and the oil gas volatilization and fire accident risk are increased. Therefore, there is still a need to develop and develop a new method and apparatus for separating Fischer-Tropsch wax from catalyst and recovering the wax.

Disclosure of Invention

The invention aims to solve the problems that the quality of Fischer-Tropsch products is influenced by an organic solvent introduced outside a Fischer-Tropsch system, the separation and recycling of the organic solvent are difficult and the extraction and separation temperature of wax and a catalyst is high in the process of recovering wax by the existing Fischer-Tropsch catalyst-containing wax residue treatment technology, and provides a method and a device for recovering wax from catalyst-containing wax residue. The method and the device do not introduce organic solvent impurities outside the Fischer-Tropsch system, do not need to increase the subsequent separation process of the wax and the organic solvent, do not influence the quality of the recovered wax, can recycle the inorganic extracting agent, and have low extraction and separation temperature.

In order to achieve the above object, a first aspect of the present invention provides a method for recovering wax from catalyst-containing wax residue, wherein the method comprises:

(1) dissolving catalyst-containing wax residue with Fischer-Tropsch produced light oil to obtain a mixed solution;

(2) mixing the mixed solution with an inorganic extractant to obtain a mixed system;

(3) standing and separating the mixed system to obtain an upper layer product, a middle layer product and a lower layer product, wherein the upper layer product is a mixture of Fischer-Tropsch self-produced light oil and wax containing less than 3 wt% of residual catalyst, the middle layer product is an inorganic extractant, and the lower layer product is a catalyst containing less than 3 wt% of residual wax; recovering the upper layer product;

the catalyst-containing wax residue comprises Fischer-Tropsch wax residue and/or wax residue, and the wax residue is a product obtained by coarsely filtering Fischer-Tropsch wax residue.

In a second aspect, the present invention provides an apparatus for recovering wax from catalyst-containing wax residue, wherein the apparatus comprises: an extractant circulating tank T-1, a wax residue dissolving tank T-2, a separating tank T-3, a filter press F-1, an extractant circulating pump P-1, a wax residue feeding pump P-2 and a wax extracting pump P-3; wherein the content of the first and second substances,

the extractant circulating pump P-1 is communicated with the extractant circulating tank T-1 and the separating tank T-3 and is used for conveying the inorganic extractant in the extractant circulating tank T-1 to the separating tank T-3 through the extractant circulating pump P-1; the wax residue dissolving tank T-2 is used for dissolving the catalyst-containing wax residue and Fischer-Tropsch self-produced light oil into a mixed solution; the wax residue feed pump P-2 is communicated with the wax residue dissolving tank T-2 and the separating tank T-3 and is used for conveying the mixed liquid into the separating tank T-3; the separation tank T-3 is used for mixing the mixed solution with an inorganic extractant and standing for separation to obtain an upper-layer product, a middle-layer product and a lower-layer product; the wax extraction pump P-3 is communicated with the upper part of the separation tank T-3 and is used for recovering and conveying an upper-layer product to a wax filtering system, and qualified wax liquid is obtained through fine filtration and separation; the filter press F-1 is communicated with the bottom of the separation tank T-3 and the extractant circulating tank T-1 and is used for carrying out filter pressing on the middle-layer product and the lower-layer product to obtain a solid-phase filter cake for solid waste treatment, and the obtained liquid phase is returned to the extractant circulating tank T-1 for recycling.

In a third aspect, the invention provides a fischer-tropsch synthesis process, wherein the process comprises:

(A) performing Fischer-Tropsch synthesis reaction on coal-based synthesis gas in a slurry bed reactor in the presence of a catalyst to obtain a Fischer-Tropsch synthesis product, generating Fischer-Tropsch wax containing the catalyst when the catalyst is replaced by the slurry bed reactor, and dividing the Fischer-Tropsch wax into a Fischer-Tropsch wax and b Fischer-Tropsch wax;

(B) carrying out coarse filtration and separation on the a strand of Fischer-Tropsch wax residues to obtain wax residue and wax liquid;

(C) carrying out the recovery method provided by the first aspect of the invention by taking the b-strand Fischer-Tropsch wax residue and/or the residue wax residue as the catalyst-containing wax residue, and carrying out fine filtration and separation on the upper-layer product obtained by the recovery method and the wax liquid to obtain qualified wax liquid;

(D) carrying out vacuum rectification on the qualified wax liquid to obtain Fischer-Tropsch self-produced light oil, heavy oil and diesel oil;

wherein the Fischer-Tropsch produced light oil is returned to step (C) for use in the recovery process.

Through the technical scheme, the invention has the beneficial effects that:

(1) the Fischer-Tropsch self-produced light oil in the Fischer-Tropsch system is fully used as an organic solvent to dissolve the catalyst-containing wax residues, a subsequent separation device for wax and the organic solvent is not required to be added, and the engagement degree with the existing Fischer-Tropsch synthesis and separation process is high;

(2) the use of the inorganic extractant can avoid the influence of organic solvent impurities outside a Fischer-Tropsch system on the quality of the recovered wax, and can realize the recycling of the extractant;

(3) the extraction and separation operation temperature is low, and the energy consumption is low.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for recovering wax from catalyst-containing wax residue according to the present invention.

Description of the reference numerals

T-1, an extractant circulating tank T-2, a wax residue dissolving tank T-3 and a separating tank

P-1, extractant circulating pump P-2, wax residue feed pump P-3 and wax extraction pump

F-1, a filter press V-16, a safety valve V-24 and a diaphragm breather valve

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The invention provides a recovery method for recovering wax from catalyst-containing wax residue, wherein the method comprises the following steps:

(1) dissolving catalyst-containing wax residue with Fischer-Tropsch produced light oil to obtain a mixed solution;

(2) mixing the mixed solution with an inorganic extractant to obtain a mixed system;

(3) standing and separating the mixed system to obtain an upper layer product, a middle layer product and a lower layer product, wherein the upper layer product is a mixture of Fischer-Tropsch self-produced light oil and wax containing less than 3 wt% of residual catalyst, the middle layer product is an inorganic extractant, and the lower layer product is a catalyst containing less than 3 wt% of residual wax; recovering the upper layer product;

the catalyst-containing wax residue comprises Fischer-Tropsch wax residue and/or wax residue, and the wax residue is a product obtained by coarsely filtering Fischer-Tropsch wax residue.

In some embodiments of the invention, the catalyst-containing wax residue comprises fischer-tropsch wax residue and/or wax residue. After the Fischer-Tropsch wax residue is subjected to coarse filtration, 97-99 wt% of wax components in the Fischer-Tropsch wax residue enter a subsequent process in the form of wax liquid for deep processing, and the residue after filtration is the residue of the Fischer-Tropsch wax residue. The wax residue is a mixture of wax and a catalyst.

In some embodiments of the present invention, in the step (1), the dissolving is performed under normal pressure and low temperature conditions, for example, the catalyst-containing wax residue and the fischer-tropsch derived light oil are dissolved in a wax residue dissolving tank to prepare a mixed solution, wherein the dissolving temperature may be 65 to 100 ℃, and the dissolving time may be 0.5 to 5 hours.

Under normal pressure, Fischer-Tropsch self-produced light oil is adopted to dissolve the wax residue containing the catalyst, so that on one hand, the mixed solution prepared by dissolution has a lower freezing point, and can keep liquid state at a lower temperature (lower than 100 ℃), namely, the wax residue has better fluidity; on the other hand, the wax component in the catalyst-containing wax residue and the catalyst mixed with the wax component can be dispersed in the mixed liquid. The two effects of the Fischer-Tropsch self-produced light oil in the process of dissolving the catalyst-containing wax residue provide favorable conditions for separating the wax from the catalyst in the subsequent steps and then recovering the wax, wherein the catalyst-containing wax residue: the mass ratio of the Fischer-Tropsch self-produced light oil is 1: (2-8).

In some embodiments of the present invention, in the step (1), preferably, the dissolving may also be performed under stirring, and the stirring may enable the catalyst-containing wax residue and the fischer-tropsch derived light oil to be dissolved and mixed more quickly, so as to accelerate the preparation of the mixed liquid, and at the same time, facilitate the sufficient dispersion of the wax component in the catalyst-containing wax residue and the solid catalyst mixed therewith in the mixed liquid, wherein the dissolving stirring rate may be 15-100 rpm.

In the invention, the Fischer-Tropsch self-produced light oil is a hydrocarbon compound of C8-C16. The Fischer-Tropsch self-produced light oil is C8-C16 light product oil produced by Fischer-Tropsch reaction, is liquid at normal temperature, has volatility, can well dissolve wax, and is easy to obtain in the Fischer-Tropsch reaction process.

In some embodiments of the present invention, in the step (2), the mixing is performed in a separation device, for example, the mixed solution and the inorganic extractant are mixed in a separation tank under stirring conditions to obtain a mixed system, wherein the mixing stirring rate can be 20 to 100 rpm, the mixing temperature can be 70 to 100 ℃, and the mixing time can be 0.5 to 5 hours.

In some embodiments of the present invention, in step (2), according to the actual production process, stirring is necessary for mixing the mixed solution and the inorganic extractant, so that the mixing rate of the two liquids can be increased, and the mixing is more sufficient, so that the inorganic extractant can better perform the extraction and separation functions, wherein the mixed solution: the volume ratio of the inorganic extractant is (0.5-4) to 1.

In some embodiments of the present invention, in step (2), the inorganic extractant is an aqueous alkaline inorganic compound solution, which is sufficiently mixed with the mixed solution in step (1) to obtain a mixed system of an oil phase, an aqueous phase and a solid phase. In the step (3), the mixed system can realize the separation of the wax and the catalyst under the alkaline environment provided by the inorganic extracting agent, and the concrete expression is that after standing, the product separated from the mixed system is divided into an upper layer, a middle layer and a lower layer under the action of gravity, and then the upper layer product, the middle layer product and the lower layer product are obtained: the upper product is an oil phase, mainly is a uniform liquid mixture of wax and Fischer-Tropsch self-produced light oil, and the wax still contains less than 3 wt% of residual catalyst according to the actual production process; the middle layer product is a water phase and is an inorganic extractant; the lower product is in solid phase and still contains less than 3 wt% residual wax for the catalyst to be separated according to the actual production process. Nevertheless, most of the wax in the catalyst-containing wax residue is separated from the catalyst by the method, and then the upper layer product is recovered and led back to the Fischer-Tropsch system to be used as a raw material for preparing Fischer-Tropsch product oil, and the Fischer-Tropsch product oil is prepared through further fine filtration separation and reduced pressure distillation.

In the present invention, the solute of the alkaline inorganic compound aqueous solution is an inorganic base and/or an alkaline inorganic salt, and is preferably NaOH or Na from the viewpoint of availability of industrial raw materials₂CO₃、KOH、K₂CO₃One or more of (a). Preferably, the pH value of the alkaline inorganic compound aqueous solution is 8-13, so that the inorganic extractant has a remarkable extraction and separation effect.

In a second aspect, the present invention provides an apparatus for recovering wax from catalyst-containing wax residue, as shown in fig. 1, wherein the apparatus comprises: an extractant circulating tank T-1, a wax residue dissolving tank T-2, a separating tank T-3, a filter press F-1, an extractant circulating pump P-1, a wax residue feeding pump P-2 and a wax extracting pump P-3; wherein the content of the first and second substances,

the extractant circulating pump P-1 is communicated with the extractant circulating tank T-1 and the separating tank T-3 and is used for conveying the inorganic extractant in the extractant circulating tank T-1 to the separating tank T-3 through the extractant circulating pump P-1; the wax residue dissolving tank T-2 is used for dissolving the catalyst-containing wax residue and Fischer-Tropsch self-produced light oil into a mixed solution; the wax residue feed pump P-2 is communicated with the wax residue dissolving tank T-2 and the separating tank T-3 and is used for conveying the mixed liquid into the separating tank T-3; the separation tank T-3 is used for mixing the mixed solution with an inorganic extractant and standing for separation to obtain an upper-layer product, a middle-layer product and a lower-layer product; the wax extraction pump P-3 is communicated with the upper part of the separation tank T-3 and is used for recovering and conveying an upper-layer product to a wax filtering system, and qualified wax liquid is obtained through fine filtration and separation; the filter press F-1 is communicated with the bottom of the separation tank T-3 and the extractant circulating tank T-1 and is used for carrying out filter pressing on the middle-layer product and the lower-layer product to obtain a solid-phase filter cake for solid waste treatment, and the obtained liquid phase is returned to the extractant circulating tank T-1 for recycling.

In some embodiments of the present invention, as shown in fig. 1, an inorganic extractant is transported from an extractant circulation tank T-1 to a separation tank T-3 by an extractant circulation pump P-1, meanwhile, a catalyst-containing wax residue and fischer-tropsch derived light oil are dissolved in a wax residue dissolution tank T-2, the prepared mixed solution is transported to the separation tank T-3 by a wax residue feed pump P-2 to be mixed and stirred with the inorganic extractant, and the obtained mixed system is subjected to standing separation to obtain an upper layer product, a middle layer product and a lower layer product: separating and recovering the upper layer product by a wax extraction pump P-3, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product into a filter press F-1 for filter pressing to obtain a solid-phase filter cake for solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In the invention, the wax residue dissolving tank T-2 and the separating tank T-3 in the device are both required to be filled with nitrogen as protective gas in advance and operated in the nitrogen atmosphere. The tank, the pump and the feeding end and the discharging end of the filter press in the device and the mutually connected pipelines are provided with a plurality of valves for controlling the trend of the materials and the nitrogen. The wax residue dissolving tank T-2 is provided with a diaphragm breather valve V-24 to ensure that the tank is continuously in a nitrogen atmosphere and ensure safety; a safety valve V-16 is arranged on the separating tank T-3 to avoid overpressure in the tank.

In the invention, pipelines related to the transportation of wax-containing materials in the device need heat tracing, so that the problem that the flowability of the wax-containing materials is poor at a lower temperature to cause pipeline blockage is avoided.

In addition, the auxiliary components of the device for recovering wax from catalyst-containing wax residue provided by the invention, such as a control valve, a liquid level meter, a gas flow meter, a liquid flow meter, a pressure test point, a temperature test point and the like, are not shown or marked in fig. 1, but the full disclosure of the device in the invention and the protection scope of the invention are not influenced.

In a third aspect, the invention provides a fischer-tropsch synthesis process, wherein the process comprises:

(A) performing Fischer-Tropsch synthesis reaction on coal-based synthesis gas in a slurry bed reactor in the presence of a catalyst to obtain a Fischer-Tropsch synthesis product, generating Fischer-Tropsch wax containing the catalyst when the catalyst is replaced by the slurry bed reactor, and dividing the Fischer-Tropsch wax into a Fischer-Tropsch wax and b Fischer-Tropsch wax;

(B) carrying out coarse filtration and separation on the a strand of Fischer-Tropsch wax residues to obtain wax residue and wax liquid;

(C) carrying out the recovery method provided by the first aspect of the invention by taking the b-strand Fischer-Tropsch wax residue and/or the residue wax residue as the catalyst-containing wax residue, and carrying out fine filtration and separation on the upper-layer product obtained by the recovery method and the wax liquid to obtain qualified wax liquid;

(D) carrying out vacuum rectification on the qualified wax liquid to obtain Fischer-Tropsch self-produced light oil, heavy oil and diesel oil;

wherein the Fischer-Tropsch produced light oil is returned to step (C) for use in the recovery process.

In some embodiments of the invention, in step (B), the wax liquid is a higher purity wax containing less than 5ppm of catalyst fines.

In some embodiments of the present invention, when the catalyst-containing wax residue includes both the b-strand fischer-tropsch wax residue and the wax residue in step (C), the recovery process may be performed after mixing the two, or may be performed separately. And the upper layer product is a mixture of Fischer-Tropsch self-produced light oil used in the recovery method and wax containing less than 3 wt% of residual catalyst, and after the mixture and the wax liquid are subjected to fine filtration and separation, the residual catalyst and catalyst particles are separated out, so that qualified wax liquid is obtained. The qualified wax liquid mainly comprises wax and Fischer-Tropsch self-produced light oil in the mixture.

In some embodiments of the present invention, in the step (D), the light fischer-tropsch derived oil obtained by vacuum distillation is composed of two parts, the first part is a product obtained by vacuum distillation of the wax component in the qualified wax liquid, and the second part is the light fischer-tropsch derived oil in the qualified wax liquid. The two parts are returned to the step (C) together for the recovery method and are reused as the solvent of the catalyst-containing wax residue.

In the present invention, since the product obtained by the vacuum distillation is not contaminated by the light fischer-tropsch derived oil used in the recovery method, it is not necessary to separate the wax in the upper product from the light fischer-tropsch derived oil, that is, it is not necessary to add a separation device, and further, in step (C), the upper product and the wax liquid may be subjected to fine filtration and separation together, without being subjected to fine filtration and separation separately.

The Fischer-Tropsch synthesis method can effectively recover wax in the catalyst-containing wax residue which is taken as a Fischer-Tropsch synthesis accessory product, and the wax is taken as a raw material for preparing Fischer-Tropsch product oil. According to the method, the Fischer-Tropsch self-produced light oil in the Fischer-Tropsch system is used as a solvent in the separation process of the wax in the catalyst-containing wax residue and the catalyst, and meanwhile, an inorganic extracting agent is used, so that the extraction and separation temperature is low, organic solvent impurities outside the system are not introduced, the quality of recovered wax is not influenced, a separation device is not required to be added, and the Fischer-Tropsch self-produced light oil and the inorganic extracting agent can be recovered and recycled.

The present invention will be described in detail below by way of examples. In the following examples, the recovery of wax was calculated according to the formula (a),

wherein C is the recovery rate of the wax; m is₁The quality of the wax residue containing the catalyst in the step (1) of the recovery method is improved; m is₂The quality of the Fischer-Tropsch self-produced light oil in the step (1) of the recovery method is improved; m is₃The quality of the upper product in step (3) of the recovery process according to the invention.

Example 1

As shown in FIG. 1, inorganic extractants (aqueous NaOH solution and Na)₂CO₃Aqueous solution pressMixing at a volume ratio of 1:1, and conveying pH 13) from an extractant circulating tank to T-1 and a separating tank to T-3; simultaneously dissolving Fischer-Tropsch wax and Fischer-Tropsch light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:5, wherein the dissolving temperature is 85 ℃, the dissolving time is 1h, and the dissolving and stirring speed is 30 r/min, so as to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to the volume ratio of 1:1, wherein the mixing temperature is 90 ℃, the mixing time is 0.5h, and the mixing and stirring speed is 50 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In the Fischer-Tropsch wax residue, the recovery rate of the wax is 95 percent.

Example 2

As shown in fig. 1, an inorganic extractant (aqueous KOH solution, pH 12) is transferred from an extractant circulation tank T-1 to a separation tank T-3; simultaneously dissolving Fischer-Tropsch wax and Fischer-Tropsch light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:6, wherein the dissolving temperature is 90 ℃, the dissolving time is 1.5 hours, and the dissolving and stirring speed is 40 revolutions per minute to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to a volume ratio of 2:1, wherein the mixing temperature is 85 ℃, the mixing time is 1h, and the mixing and stirring speed is 40 r/min, so as to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In the Fischer-Tropsch wax residue, the recovery rate of the wax was 93%.

Example 3

As shown in FIG. 1, inorganic extractants (NaOH aqueous solution and K)₂CO₃Mixing the aqueous solution at a volume ratio of 1:1, wherein the pH value is 12), and conveying the aqueous solution from an extractant circulating tank to T-1 and conveying the aqueous solution to a separation tank to T-3; simultaneously dissolving the residue wax residue and Fischer-Tropsch self-produced light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:5, wherein the dissolving temperature is 95 ℃, the dissolving time is 2 hours, and the dissolving and stirring speed is 50 revolutions per minute to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to the volume ratio of 1:1, wherein the mixing temperature is 95 ℃, the mixing time is 1.5h, and the mixing and stirring speed is 50 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

The recovery of wax from the residue was 96%.

Example 4

As shown in fig. 1, an inorganic extractant (NaOH aqueous solution, pH 10) is transferred from an extractant circulation tank T-1 to a separation tank T-3; simultaneously dissolving the mixture of the Fischer-Tropsch wax residue and the wax residue and Fischer-Tropsch self-produced light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:2, wherein the dissolving temperature is 100 ℃, the dissolving time is 5 hours, and the dissolving and stirring speed is 15 revolutions per minute to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to the volume ratio of 0.5:1, wherein the mixing temperature is 70 ℃, the mixing time is 2 hours, and the mixing and stirring speed is 100 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

The recovery of wax from the mixture of Fischer-Tropsch wax residue and wax residue was 90%.

Example 5

As shown in FIG. 1, an inorganic extractant (Na)₂CO₃Aqueous solution with pH 8) is conveyed from an extractant circulating tank to T-1 and then to a separating tank to T-3; simultaneously dissolving Fischer-Tropsch wax and Fischer-Tropsch light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:8, wherein the dissolving temperature is 65 ℃, the dissolving time is 0.5h, and the dissolving and stirring speed is 100 revolutions per minute to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to a volume ratio of 2:1, wherein the mixing temperature is 100 ℃, the mixing time is 5 hours, and the mixing and stirring speed is 20 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In the Fischer-Tropsch wax residue, the recovery rate of the wax was 89%.

Example 6

As shown in fig. 1, an inorganic extractant (aqueous KOH solution, pH 11) is transferred from an extractant circulation tank T-1 to a separation tank T-3; simultaneously dissolving Fischer-Tropsch wax and Fischer-Tropsch light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:3, wherein the dissolving temperature is 90 ℃, the dissolving time is 2 hours, and the dissolving and stirring speed is 40 revolutions per minute to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to a volume ratio of 4:1, wherein the mixing temperature is 80 ℃, the mixing time is 1h, and the mixing and stirring speed is 40 r/min, so as to obtain a mixed system; and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In Fischer-Tropsch wax, the recovery of wax was 88%.

Example 7

As shown in FIG. 1, an inorganic extractant (K)₂CO₃Aqueous solution with pH 9) is conveyed from an extractant circulating tank to T-1 and then to a separating tank to T-3; simultaneously dissolving Fischer-Tropsch wax and Fischer-Tropsch light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:6, wherein the dissolving temperature is 75 ℃, the dissolving time is 1h, and the dissolving and stirring speed is 40 r/min, so as to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to a volume ratio of 3:1, wherein the mixing temperature is 75 ℃, the mixing time is 3 hours, and the mixing and stirring speed is 60 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In the Fischer-Tropsch wax residue, the recovery rate of the wax was 86%.

Example 8

As shown in fig. 1, an inorganic extractant (aqueous KOH solution, pH 13) is transferred from an extractant circulation tank T-1 to a separation tank T-3; simultaneously dissolving Fischer-Tropsch wax and Fischer-Tropsch light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:5, wherein the dissolving temperature is 85 ℃, the dissolving time is 1h, and the dissolving and stirring speed is 30 r/min, so as to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to the volume ratio of 1:1, wherein the mixing temperature is 90 ℃, the mixing time is 0.5h, and the mixing and stirring speed is 50 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In the Fischer-Tropsch wax residue, the recovery rate of the wax is 94 percent.

Example 9

As shown in FIG. 1, inorganic extractants (aqueous NaOH solution and Na)₂CO₃Mixing the aqueous solution at a volume ratio of 1:1, wherein the pH value is 13), and conveying the aqueous solution from an extractant circulating tank to T-1 and conveying the aqueous solution to a separation tank to T-3; simultaneously dissolving the residue wax residue and Fischer-Tropsch self-produced light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:3, wherein the dissolving temperature is 75 ℃, the dissolving time is 1h, and the dissolving and stirring speed is 30 r/min, so as to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to the volume ratio of 1:1, wherein the mixing temperature is 90 ℃, the mixing time is 0.5h, and the mixing and stirring speed is 50 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

The recovery of wax from the residue was 93%.

Example 10

As shown in FIG. 1, inorganic extractants (aqueous NaOH solution and Na)₂CO₃Mixing the aqueous solution at a volume ratio of 1:1, wherein the pH value is 13), and conveying the aqueous solution from an extractant circulating tank to T-1 and conveying the aqueous solution to a separation tank to T-3; simultaneously dissolving Fischer-Tropsch wax residue and Fischer-Tropsch light oil in a wax residue dissolving tank T-2 according to the mass ratio of 1:3, and dissolvingThe temperature is 75 ℃, the dissolving time is 1h, and the dissolving and stirring speed is 30 r/min, so as to prepare a mixed solution;

conveying the mixed solution into a separation tank T-3, mixing and stirring the mixed solution and an inorganic extractant according to the volume ratio of 1:1, wherein the mixing temperature is 80 ℃, the mixing time is 0.5h, and the mixing and stirring speed is 50 revolutions per minute to obtain a mixed system;

and (3) standing and separating the mixed system in a separation tank T3 to obtain an upper layer product, a middle layer product and a lower layer product: recovering the upper layer product, conveying the upper layer product to a wax filtering system, and carrying out fine filtration and separation to obtain qualified wax liquid; and discharging the middle-layer product and the lower-layer product from the tank bottom, performing pressure filtration by using a pressure filter to obtain a solid-phase filter cake, performing solid waste treatment, and returning the obtained liquid phase to the extractant circulating tank T-1 for recycling.

In the Fischer-Tropsch wax residue, the recovery rate of the wax is 91 percent.

Comparative example 1

The procedure of example 1 was followed except that the inorganic extractant was an aqueous NaCl solution. The rest is the same as in example 1.

In the Fischer-Tropsch wax residue, the recovery rate of the wax is 10 percent.

Comparative example 2

The method of example 1 was followed except that, in the step (2), the mixing temperature of the mixed solution and the inorganic extractant was 65 ℃. The rest is the same as in example 1.

In the Fischer-Tropsch wax residue, the recovery rate of the wax is 33 percent.

As can be seen by comparing the results of examples 1-10 with the comparative example, the recovery of wax was high when the treatment was carried out by the method and apparatus of the present invention, while the recovery of wax was low in the comparative example.

In particular, the inorganic extractant in comparative example 1 is an aqueous NaCl solution, which has a weak extraction and separation effect, and the recovery rate of wax is very low; the mixed liquid and the inorganic extractant in the comparative example 2 have low mixing temperature, so that the extraction and separation effects of the inorganic extractant are not ideal, and the recovery rate of the wax is obviously lower than that of the examples 1 to 10.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.