阅读说明：本技术 含固费托合成产品的水洗固液分离方法及实施其的系统 (Water washing solid-liquid separation method for solid-containing Fischer-Tropsch synthesis product and system for implementing water washing solid-liquid separation method ) 是由 贾梦磊 耿春宇 陶智超 张丽 陈彪 龙爱斌 刘晓娜 高军虎 郝栩 董根全 杨勇 于 2020-06-09 设计创作，主要内容包括：本发明涉及一种含固费托合成产品的水洗固液分离方法以及用于实施该方法的系统。其中,通过将含固费托合成产品与水进行混合,然后再进行分离,能够高效地分离出含固费托合成产品中的微米级固体颗粒,并且整个系统的运行成本更低,且易于工业化。(The invention relates to a water washing solid-liquid separation method of solid-containing Fischer-Tropsch synthesis products and a system for implementing the method. Wherein, through will contain solid Fischer-Tropsch synthesis product and water and mix, then separate, can separate out the micron order solid particle in the solid Fischer-Tropsch synthesis product with high efficiency to the running cost of entire system is lower, and easily industrialization.)

1. A water washing solid-liquid separation method of solid-containing Fischer-Tropsch synthesis products comprises the following steps:

(1) mixing the solid Fischer-Tropsch synthesis product with water to obtain a mixture of the solid Fischer-Tropsch synthesis product and the water; and

(2) and separating the solid Fischer-Tropsch synthesis product from the water mixture to obtain the solid removed Fischer-Tropsch synthesis product and the solid containing water phase.

2. The aqueous washing solid-liquid separation method of claim 1, wherein the solid content fischer-tropsch synthesis product is a fischer-tropsch synthesis product with a solid content of more than 0 wt% and not more than 1 wt%; preferably, the solid content of the Fischer-Tropsch synthesis product is more than 0 wt% and less than or equal to 0.5 wt%; more preferably, the solid content of the Fischer-Tropsch synthesis product is more than 0 wt% and less than or equal to 0.1 wt%;

preferably, the solid-containing Fischer-Tropsch synthesis product is selected from Fischer-Tropsch synthesis oil phase products, purified crude oil, normal pressure heavy oil or Fischer-Tropsch synthesis crude products which are generated by a slurry bed Fischer-Tropsch synthesis reactor and are obtained after filtration and separation; more preferably, the Fischer-Tropsch synthesis oil phase product is selected from Fischer-Tropsch synthesis light oil with an initial boiling point of below 80 ℃, Fischer-Tropsch synthesis heavy oil with an initial boiling point of above 100 ℃, Fischer-Tropsch synthesis wax with a condensation point of above 100 ℃, filter wax and/or stabilizing wax;

preferably, the solid in the solid-containing Fischer-Tropsch synthesis product has a particle size of 0.1-500 μm.

3. The aqueous wash solid-liquid separation method of claim 1 or 2, wherein the water is desalted water, deionized water and/or fischer-tropsch synthesis water.

4. The aqueous wash solid-liquid separation process of any one of claims 1 to 3, wherein an acidic substance is added to the water prior to mixing the solid-containing Fischer-Tropsch synthesis product with the water; preferably, the acidic substance is selected from hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, oleic acid, stearic acid, or any mixture thereof;

preferably, a surfactant, a flocculant, a corrosion and scale inhibitor, a dispersant and/or a precipitant are added to the water before mixing the solid-containing fischer-tropsch synthesis product with the water; preferably, the surfactant is selected from methyl stearate, methyl oleate and/or methyl palmitate; the flocculant is selected from polyacrylamide, amino ethyl acrylic acid and/or polyaluminium chloride; the corrosion and scale inhibitor is selected from hydroxyethylidene diphosphonic acid, 2-acrylamide-2-methylpropanesulfonic acid, 2-phosphate-1, 2, 4-tricarboxylic acid butane and/or 2-hydroxyphosphonoacetic acid; the dispersant is selected from polyaspartic acid, polyepoxysuccinic acid and/or polymaleic acid; the precipitant is selected from palmitic acid and/or SA-20.

5. The water washing solid-liquid separation method according to any one of claims 1 to 4, wherein the solid-containing Fischer-Tropsch synthesis product and the water are mixed in a mass ratio of 1:20 to 20: 1;

preferably, the solid fischer-tropsch synthesis product is mixed with the water at a temperature between the condensation point and the boiling point of the solid fischer-tropsch synthesis product;

preferably, the mixing is carried out at a temperature such that the viscosity of the solid-containing Fischer-Tropsch synthesis product is from 0 to 10mPa s; more preferably, the mixing is carried out at a temperature of 60 to 260 ℃;

preferably, the pressure of the mixing is 0-5 MPaG;

preferably, steam, N, is introduced when mixing the solid Fischer-Tropsch synthesis product with the water₂And/or an inert gas;

preferably, the mixing is carried out using one or more devices selected from: a kettle reactor, a static mixer, a pipeline type ultrahigh-speed emulsifying machine and an intermittent emulsifying kettle.

6. The water washing solid-liquid separation method according to any one of claims 1 to 5, wherein the solid-containing Fischer-Tropsch synthesis product is mixed with the water for 10 to 30min and then separated from the water mixture;

preferably, the solid-containing fischer-tropsch synthesis product is separated from the water mixture by one or more means selected from: filtering, settling, cyclone separation or centrifugal separation.

7. The aqueous wash solid-liquid separation method of any one of claims 1-6, wherein the method further comprises: before step (1), feeding the solid-containing Fischer-Tropsch synthesis product and the water after buffering respectively;

preferably, the method further comprises: prior to step (1), heat exchanging the solid fischer-tropsch synthesis product with the water, preferably by steam heating or electrical heating;

preferably, the method further comprises: before the step (1), carrying out heat preservation and heat tracing treatment on the solid-containing Fischer-Tropsch synthesis product after heat exchange and water;

preferably, the method further comprises: carrying out oil-water separation on the solid-containing water phase to obtain oil-removing Fischer-Tropsch synthetic water and solid-containing emulsified oil; preferably, a part of the deoiled Fischer-Tropsch synthesis water is returned to the step (1) for use in the mixing, and the rest part of the deoiled Fischer-Tropsch synthesis water is subjected to downstream water treatment; further preferably, the solids-containing emulsified oil is returned to step (1) for use in the mixing;

preferably, the method further comprises: and carrying out flash evaporation treatment on the Fischer-Tropsch synthesis product subjected to solid removal to obtain a flash evaporated Fischer-Tropsch synthesis product and non-condensable gas.

8. The aqueous wash solid-liquid separation method of any one of claims 1 to 7, wherein the method comprises the steps of:

(i) respectively buffering the solid Fischer-Tropsch synthesis product and the water and then feeding;

(ii) carrying out heat exchange on the fed solid-containing Fischer-Tropsch synthesis product and water;

(iii) mixing the solid Fischer-Tropsch synthesis product subjected to heat exchange with water to obtain a mixture of the solid Fischer-Tropsch synthesis product and the water;

(iv) carrying out cyclone separation on the solid-containing Fischer-Tropsch synthesis product and a water mixture to obtain the solid-removed Fischer-Tropsch synthesis product and the solid-containing water phase;

(v) (iv) subjecting the Fischer-Tropsch synthesis product subjected to solid removal to flash evaporation treatment to obtain a flash evaporated Fischer-Tropsch synthesis product and non-condensable gas, and returning part of the flash evaporated Fischer-Tropsch synthesis product to the step (iii) for mixing; and

(vi) carrying out cyclone separation on the solid-containing water phase to obtain oil-removing Fischer-Tropsch synthetic water and solid-containing emulsified oil; (iv) returning a portion of the deoiled fischer-tropsch synthesis water to step (iii) for use in the mixing, and subjecting the remaining portion of the deoiled fischer-tropsch synthesis water to downstream water treatment; optionally, the solids-containing emulsified oil is returned to step (iii) for use in the mixing.

9. A system for carrying out the aqueous wash solid-liquid separation method of any one of claims 1-8, wherein the system comprises:

an oil-water mixing device;

an oil-water separator connected in fluid communication to the oil-water mixing device.

10. The system of claim 9, wherein the system further comprises a solid fischer-tropsch synthesis product containing surge tank and a water surge tank;

preferably, the system further comprises a heat exchanger; more preferably, the heat exchanger is a tube heat exchanger and/or a plate heat exchanger;

preferably, the system further comprises a heat-insulating heat tracing device;

preferably, the system further comprises a fischer-tropsch synthesis product collection tank;

preferably, the system further comprises a flash separation tank;

preferably, the system further comprises a waste water collection tank;

preferably, the system further comprises an emulsified oil mixed liquor collection tank;

preferably, the oil-water mixing device is a kettle reactor, a static mixer, a pipeline type ultra-high speed emulsifying machine or an intermittent emulsifying kettle;

preferably, the oil-water separation device is a cyclone oil-water separation tank.

Technical Field

The invention belongs to the field of Fischer-Tropsch synthesis, and particularly relates to a water washing solid-liquid separation method for a solid Fischer-Tropsch synthesis product and a system for implementing the method.

Background

The energy is a power source for national industry, economy and social operation and is also the foundation for the survival and social development of modern human beings. Coal indirect liquefaction takes coal as a raw material, the coal is converted into synthesis gas through processes of gasification, purification, water gas shift and the like, the synthesis gas is converted into a clean intermediate oil product through a Fischer-Tropsch synthesis process, and products such as clean gasoline, diesel oil, wax and the like and high value-added chemicals are formed through fine processing of the intermediate oil product.

In the started Fischer-Tropsch synthesis project, the slurry bed reactor is mostly adopted to carry out the Fischer-Tropsch synthesis reaction because the slurry bed reactor has the advantages of good heat transfer performance, easy control of reaction temperature, controllable product selectivity, high product quality and the like. An important operation of the slurry bed reactor is solid-liquid separation, wherein the intermediate oil product in Fischer-Tropsch synthesis still contains micron-sized solid catalyst particles with low solid content after being filtered in the reactor, and the solid particles need to be separated and then enter the next unit, otherwise, the equipment of a downstream unit can not be smoothly operated or the catalyst of a downstream process unit can be poisoned, so that the operation stability of a plant is influenced.

At present, the main means for solid-liquid separation of solid-containing Fischer-Tropsch synthesis products in industry are as follows: filtration, sedimentation, centrifugation, magnetic separation, electrical separation, membrane separation, and the like. The separation method for the product containing fine particles mainly comprises centrifugation and filtration, and is influenced by operating conditions, and the main adverse factors of the two separation modes are high investment cost; the centrifugal separation method needs to consider the heat resistance of a rotating shaft of the centrifugal machine, and the rotating shaft is easy to damage when the centrifugal machine is operated at high temperature for a long time, so that the service life and the processing capacity of centrifugal equipment are reduced; although the conventional filtration and separation method is a mature and widely applied mode at present, when the solid content is less than 100 mug/g, a large amount of filter aid is generally added, a certain pressure is sometimes required to be applied for achieving the separation purpose, a large amount of waste solids are generated, the problem of volatile organic matter emission also exists, the investment and operation cost is extremely high, and the operation environment is severe.

Patent CN101733045B discloses a device of slurry bed reactor solid-liquid separation, but its whole separation process is complicated, and the membrane separation equipment who especially uses extremely easily makes the membrane jam in the separation application process of ft oil, and regeneration difficulty, and the membrane separation area is directly proportional with catalyst content moreover, and it is great to need the membrane separation area when catalyst content is higher, and equipment investment is higher. Patent CN1829787B discloses a Fischer-Tropsch synthesis product acid treatment method, which uses an aqueous acidic stream with strong acidity to reduce the blockage of a downstream hydrogenation catalyst bed and improve the hydrogenation reaction efficiency, and reduces the blockage of the catalyst bed in a downstream hydrogenation treatment reactor by extracting pollutants in a Fischer-Tropsch reaction alkane product. The aqueous acidic stream has stronger acidity, so the corrosion resistance of equipment needs to be improved, and the equipment cost is increased; the acidic substance itself also introduces new contaminants to the product, affecting product quality. Patent CN103846160B discloses a magnetic separation method of slurry bed fischer-tropsch synthesis heavy product and catalyst, but the solid content at the outlet of the filter is multiplied with the increase of the treatment capacity, and the solid content of the separated product is still high. Patent CN102553343B discloses a method for filtering and separating catalyst and product of slurry bed synthetic liquid fuel, which is characterized in that the residual catalyst in oil products can cause adverse effect on the subsequent treatment process due to insufficient filtering precision and incomplete separation.

Therefore, there is a need for a simple and efficient solid-liquid separation process for solid-containing Fischer-Tropsch synthesis products, and further, it is desirable to have a reduced cost.

Disclosure of Invention

In view of the above technical problems, the present invention provides a water washing solid-liquid separation method with simple process and continuous operation, wherein micron-sized solid particles in fischer-tropsch synthesis products can be efficiently separated by adopting a water washing manner, and a system for implementing the method. The process of the invention is particularly suitable for the separation of solid particles from Fischer-Tropsch synthesis products of low solids content, which cannot be removed by conventional filtration.

In one aspect, the invention provides a water washing solid-liquid separation method of a solid-containing Fischer-Tropsch synthesis product, which comprises the following steps:

(1) mixing the solid Fischer-Tropsch synthesis product with water to obtain a mixture of the solid Fischer-Tropsch synthesis product and the water; and

(2) and separating the solid Fischer-Tropsch synthesis product from the water mixture to obtain the solid removed Fischer-Tropsch synthesis product and the solid containing water phase.

In another aspect, the present invention provides a system for implementing the above method, wherein the system comprises:

an oil-water mixing device;

an oil-water separator connected in fluid communication to the oil-water mixing device.

The washing solid-liquid separation method provided by the invention realizes the following technical advantages:

1. the separation method has higher treatment capacity on the solid-containing Fischer-Tropsch synthesis product, and compared with the filter aid solid removal filtration process, the separation method has the advantages that the investment and operation cost can be reduced by 50 percent, and the industrial realization is easy;

2. the solid content of the oil product subjected to solid-liquid separation by the method can usually reach below 10 mu g/g, and compared with the traditional solid-liquid separation method, the solid separation efficiency is higher (more than 60 percent, even more than 95 percent of solid particles in the solid-containing Fischer-Tropsch synthesis product can be separated);

3. the invention can carry out water washing separation by adopting water generated by Fischer-Tropsch synthesis reaction without increasing water consumption, and can treat and recycle the water after separation, thereby saving water consumption and reducing water consumption.

Drawings

FIG. 1 is a schematic of an exemplary water wash solid liquid separation process of the present invention.

FIG. 2 is a schematic view of the process of the present invention.

Wherein each reference numeral respectively denotes: 1. a buffer tank for solid-containing Fischer-Tropsch synthesis products; 2. a water buffer tank; 3. a static mixer; 4. a cyclone oil-water separation tank; 5. a Fischer-Tropsch synthesis product collecting tank; 6. a flash separation tank; 7. a wastewater collection tank; 8. an emulsified oil mixed liquid collection tank; 9. a Fischer-Tropsch synthesis product heat exchanger; 10. a water heat exchanger; 101 contains a solid fischer-tropsch synthesis product; 102 fischer-tropsch synthesis product stream; 103 Fischer-Tropsch synthesis product stream after heat exchange; 104 Fischer-Tropsch synthesis water; 105 fischer-tropsch synthesis water stream; 106 Fischer-Tropsch synthesis water stream; 107 containing a pre-mix stream of solid Fischer-Tropsch synthesis products and synthesis water; 108 oil-water mixed product stream; 109 removing the solid Fischer-Tropsch synthesis product stream; 110 a product stream from a product collection tank; 111 of a flashed fischer-tropsch synthesis product; 112 non-condensable gas; 113 pressurized stream; 114 a Fischer-Tropsch synthesis water stream; 115 a stream containing solid emulsified oil; 116 a stream from a waste water collection tank; 117 stream to be treated with water; 118 removing the solid fischer-tropsch synthesis product stream; 119 diluting the stream of the stream.

Detailed Description

The following describes exemplary embodiments, but the scope of the present invention is not limited to these embodiments.

In the present invention, unless otherwise specified, the fischer-tropsch synthesis product refers to the liquid phase product (also referred to as "oil") produced by the fischer-tropsch synthesis reaction of a carbonaceous feedstock.

In one embodiment, the invention relates to a water wash solid-liquid separation method for solid-containing Fischer-Tropsch synthesis products, which comprises the following steps:

(1) mixing the solid Fischer-Tropsch synthesis product with water to obtain a mixture of the solid Fischer-Tropsch synthesis product and the water; and

(2) and separating the solid Fischer-Tropsch synthesis product from the water mixture to obtain the solid removed Fischer-Tropsch synthesis product and the solid containing water phase.

In a preferred embodiment, the solid-containing fischer-tropsch synthesis product may be a fischer-tropsch synthesis product having a solid content of from greater than 0 wt% to equal to or less than 1 wt%, preferably from greater than 0 wt% to equal to or less than 0.5 wt%, more preferably from greater than 0 wt% to equal to or less than 0.1 wt%. If the solid content of the Fischer-Tropsch synthesis product is higher than 1 wt%, the Fischer-Tropsch synthesis product can be used as the solid-containing Fischer-Tropsch synthesis product of the invention after being filtered and pretreated.

In a preferred embodiment, the solid-containing Fischer-Tropsch synthesis product described herein may comprise: Fischer-Tropsch synthesis oil phase products such as Fischer-Tropsch synthesis light oil having an initial boiling point of 80 ℃ or lower, Fischer-Tropsch synthesis heavy oil having an initial boiling point of 100 ℃ or higher, Fischer-Tropsch synthesis wax having a freezing point of higher than 100 ℃, filter wax, and stabilizer wax; purifying crude oil and normal pressure heavy oil; the crude product of Fischer-Tropsch synthesis obtained by filtering and separating the crude product from the slurry bed Fischer-Tropsch synthesis reactor is not limited to the above.

In a preferred embodiment, the solid has a particle size of 0.1 to 500 μm in the solid-containing Fischer-Tropsch synthesis product.

In a preferred embodiment, the water may be desalted water, deionized water and/or Fischer-Tropsch synthesis water. Preferably, the Fischer-Tropsch synthesis water can be Fischer-Tropsch synthesis reaction crude water obtained by carrying out Fischer-Tropsch synthesis reaction on synthesis gas, and can also be Fischer-Tropsch synthesis product purified water obtained by separating out water phase by-products from the Fischer-Tropsch synthesis reaction crude water.

In a preferred embodiment, an acidic substance may be added to the water prior to mixing the solid Fischer-Tropsch synthesis product with the water, which will facilitate further removal of solid particles from the solid Fischer-Tropsch synthesis product. Preferably, the acidic substance may be, for example, an inorganic acid, an organic acid, or a mixture thereof, and more preferably, the inorganic acid may be hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, or any mixture thereof; the organic acid may be formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, oleic acid, stearic acid, or any mixture thereof.

In a preferred embodiment, a surfactant, a flocculant, a corrosion and scale inhibitor, a dispersant and/or a precipitant may be added to the water prior to mixing the solid-containing fischer-tropsch synthesis product with the water. Preferably, the surfactant may be selected from methyl stearate, methyl oleate and/or methyl palmitate. Preferably, the flocculating agent may be selected from polyacrylamide, amino ethyl acrylic acid and/or polyaluminium chloride. Preferably, the corrosion and scale inhibitor may be selected from hydroxyethylidene diphosphonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-phosphate-1, 2, 4-tricarboxylic acid butane and/or 2-hydroxyphosphonoacetic acid. Preferably, the dispersant may be selected from polyaspartic acid, polyepoxysuccinic acid, polymaleic acid. Preferably, the precipitating agent may be selected from palmitic acid and/or SA-20.

In a preferred embodiment, the solid-containing Fischer-Tropsch synthesis product is mixed with water in a mass ratio of 1:20 to 20:1, preferably 1:5 to 5:1, more preferably 1:3 to 3: 1.

In a preferred embodiment, the solid Fischer-Tropsch synthesis product is mixed with water at a temperature between the freezing point and the boiling point of the solid Fischer-Tropsch synthesis product (i.e. the initial boiling point of the mixture of solid Fischer-Tropsch synthesis product and water under the mixing conditions). The freezing point and the initial boiling point of the solid-containing Fischer-Tropsch synthesis product may be determined by conventional means in the art (e.g.using the assay described in GB/T510 for the freezing point and GB/T6536, GB/T9168 and/or SH/T0558 for the initial boiling point). The high temperature is advantageous for reducing the viscosity of the solid-containing Fischer-Tropsch synthesis product and improving the mixing efficiency, and therefore, the mixing is preferably performed at a temperature such that the viscosity of the solid-containing Fischer-Tropsch synthesis product is 0 to 10mPa · s, preferably 0 to 5mPa · s, and more preferably 0 to 3mPa · s. Preferably, the mixing is carried out at a temperature of 10 to 30 ℃ higher than the freezing point or 30 to 50 ℃ lower than the boiling point, for example, at a temperature of 60 to 260 ℃, preferably 80 to 200 ℃.

In a preferred embodiment, the pressure at which the solid Fischer-Tropsch synthesis product is mixed with water is referenced to the vapour pressure of water at the temperature of said mixing, said mixing pressure being higher than the saturation vapour pressure of water at the temperature of said mixingTherefore, the water is ensured to be liquid water under the mixed temperature and pressure, the energy consumption is reduced, and the energy consumption loss caused by water gasification is avoided. Preferably, the pressure of the mixing may be 0 to 5MPaG, preferably 0.5 to 3 MPaG. Preferably, the solid Fischer-Tropsch synthesis product is mixed with water by introducing steam, N₂And/or inert gas (preferably water vapor and/or N)₂) To maintain the pressure stable. Preferably, the inert gas may be Ar, He, or the like.

The mixing can be carried out by high-pressure mixing equipment commonly used in chemical production. In a preferred embodiment, the mixing may be carried out using one or more devices selected from the group consisting of: kettle type reactor, static mixer, pipeline type ultra-high speed emulsifying machine, and batch emulsifying kettle. The processing capacity of the equipment can be selected according to the solid content, the Fischer-Tropsch synthesis product processing capacity and the oil-water ratio.

In a preferred embodiment, after the solid Fischer-Tropsch synthesis product is mixed with water for 10-30 min, the solid Fischer-Tropsch synthesis product is separated from the water mixture.

In separating the solid Fischer-Tropsch synthesis product from the water mixture, the same or different temperatures and pressures may be used, preferably the same temperatures and pressures are used, as for the mixing.

In a preferred embodiment, the solid Fischer-Tropsch synthesis product may be separated from the aqueous mixture by one or more means selected from the group consisting of: filtration, sedimentation, cyclonic or centrifugal separation, preferably cyclonic separation. According to the density difference between the Fischer-Tropsch synthesis product and water, when the solid Fischer-Tropsch synthesis product is separated from the water mixture, the solid in the solid Fischer-Tropsch synthesis product enters the water phase from the oil phase due to the affinity action of the water, and is finally separated from the solid Fischer-Tropsch synthesis product.

In a preferred embodiment, the method further comprises: before the step (1), the solid Fischer-Tropsch synthesis product and water are respectively fed after being buffered.

In a preferred embodiment, the method further comprises: heat exchanging the solid-containing fischer-tropsch synthesis product with the water prior to step (1). Preferably, the heat exchange is performed by steam heating or electric heating. Further preferably, before the step (1), the solid Fischer-Tropsch synthesis product and the water after heat exchange are subjected to heat preservation and heat tracing treatment. Preferably, the heat-retention tracing treatment is performed by electric tracing and/or steam tracing, more preferably by steam tracing.

In a preferred embodiment, the method further comprises: and further carrying out oil-water separation on the solid-containing water phase to obtain oil-removing Fischer-Tropsch synthetic water and solid-containing emulsified oil. Preferably, the deoiled Fischer-Tropsch synthesis water is collected, a part of the deoiled Fischer-Tropsch synthesis water is returned to the step (1) for being used in the mixing, and the rest part of the deoiled Fischer-Tropsch synthesis water is subjected to downstream water treatment. Further preferably, after collecting the solids-containing emulsified oil, the solids-containing emulsified oil is returned to step (1) for use in the mixing.

In a preferred embodiment, the method further comprises: and after collecting the solid-removed Fischer-Tropsch synthesis product, carrying out flash evaporation treatment on the solid-removed Fischer-Tropsch synthesis product to obtain a flash-evaporated Fischer-Tropsch synthesis product and non-condensable gas. Preferably, the temperature of the flash evaporation treatment is 100-300 ℃, and the pressure is 0-0.5 MPaG. Preferably, a portion of the flashed Fischer-Tropsch synthesis product is returned to step (1) for use in the mixing.

In a preferred embodiment, the aqueous washing solid-liquid separation method of the solid-containing Fischer-Tropsch synthesis product comprises the following steps:

(i) respectively buffering the solid Fischer-Tropsch synthesis product and the water and then feeding;

(ii) carrying out heat exchange on the fed solid-containing Fischer-Tropsch synthesis product and water;

(iii) mixing the solid Fischer-Tropsch synthesis product subjected to heat exchange with water to obtain a mixture of the solid Fischer-Tropsch synthesis product and the water;

(iv) carrying out cyclone separation on the solid-containing Fischer-Tropsch synthesis product and a water mixture to obtain a solid-removed Fischer-Tropsch synthesis product and a solid-containing water phase;

(v) (iv) subjecting the Fischer-Tropsch synthesis product subjected to solid removal to flash evaporation treatment to obtain a flash evaporated Fischer-Tropsch synthesis product and non-condensable gas, and returning part of the flash evaporated Fischer-Tropsch synthesis product to the step (iii) for mixing; and

(vi) carrying out cyclone separation on the solid-containing water phase to obtain oil-removing Fischer-Tropsch synthetic water and solid-containing emulsified oil; (iv) returning a portion of the deoiled fischer-tropsch synthesis water to step (iii) for use in the mixing, and subjecting the remaining portion of the deoiled fischer-tropsch synthesis water to downstream water treatment; optionally, returning the solids-containing emulsified oil to step (iii) for use in the mixing.

In one embodiment, the present invention provides a system for implementing the above method, wherein the system comprises:

an oil-water mixing device;

an oil-water separator connected in fluid communication to the oil-water mixing device.

In a preferred embodiment, the system further comprises a solid Fischer-Tropsch synthesis product containing surge tank and a water surge tank.

In a preferred embodiment, the system further comprises a heat exchanger. Preferably, the heat exchanger can be a tube heat exchanger and/or a plate heat exchanger and the like. If the melting point of the treated Fischer-Tropsch synthesis product is relatively high, it is preferred that the system further comprises a heat retention tracing apparatus.

In a preferred embodiment, the system further comprises a fischer-tropsch synthesis product collection tank.

In a preferred embodiment, the system further comprises a flash separation tank.

In a preferred embodiment, the system further comprises a waste water collection tank.

In a preferred embodiment, the system further comprises an emulsified oil mixed liquor collection tank.

In a preferred embodiment, the oil-water separation device is a cyclone oil-water separation tank. Because the solid particle size in the solid-containing Fischer-Tropsch synthesis product is smaller, the oil-water separation time can be further shortened by adopting the cyclone oil-water separation tank, so that the oil-water separation efficiency and the oil yield are further improved. Preferably, the cyclone oil-water separation tank comprises a cyclone separator, a flow stabilizing and emulsion breaking oil phase gathering inner component and a baffle. Wherein, the Fischer-Tropsch synthesis product after solid removal flows out from an overflow port at the top of the cyclone separator, the water phase containing solid flows out from a bottom flow port of the cyclone separator, and solid slag is discharged periodically. The flow of the top overflow port and the bottom flow port of the cyclone separator in the cyclone oil-water separation tank can be controlled to be 1: 20-20: 1, preferably 1: 5-5: 1, and more preferably 1: 3-3: 1 according to the oil-water mixing ratio.

Further preferably, the cyclone separator is a liquid-liquid cyclone separator, preferably selected from a dewatering type cyclone separator or a deoiling type cyclone separator. If the water content of the Fischer-Tropsch synthesis product overflowing from the top of the cyclone separator is high, the second-stage and/or multi-stage cyclone separation can be carried out on the Fischer-Tropsch synthesis product by adopting a dehydration type cyclone separator, the standing separation can be carried out by adopting a settling oil-water separation tank, or the water is gasified and separated by adopting a flash tank. When a settling oil-water separation tank is adopted for standing separation, the retention time of materials is higher than 5min, preferably lower than 30 min; when the flash tank is adopted to gasify water, the gasification temperature needs to be controlled to be 100-300 ℃, and the pressure needs to be controlled to be 0-0.5 MPaG.

In a preferred embodiment, the oil-water mixing device is a tank reactor, a static mixer, a pipeline ultra-high-speed emulsifying machine or a batch emulsifying tank, preferably a tank reactor or a static mixer.

Each device in the system can be a normal pressure device and/or a high pressure device according to the mixing condition, and the temperature-resistant and pressure-resistant condition can be determined according to the material property and the mixing and separating condition.

Exemplary aspects of the present invention may be illustrated by the following numbered paragraphs, but the scope of the present invention is not limited thereto:

1. a water washing solid-liquid separation method of solid-containing Fischer-Tropsch synthesis products comprises the following steps:

(1) mixing the solid Fischer-Tropsch synthesis product with water to obtain a mixture of the solid Fischer-Tropsch synthesis product and the water; and

(2) and separating the solid Fischer-Tropsch synthesis product from the water mixture to obtain the solid removed Fischer-Tropsch synthesis product and the solid containing water phase.

2. The aqueous washing solid-liquid separation method of paragraph 1 wherein the solid-containing fischer-tropsch synthesis product is a fischer-tropsch synthesis product having a solid content of greater than 0 wt% to equal to or less than 1 wt%.

3. The aqueous washing solid-liquid separation method of paragraph 1 or 2, wherein the solid-containing fischer-tropsch synthesis product is a fischer-tropsch synthesis product having a solid content of more than 0 wt% and not more than 0.5 wt%.

4. The aqueous washing solid-liquid separation method of any one of paragraphs 1 to 3, wherein the solid content of the Fischer-Tropsch synthesis product is greater than 0 wt% and equal to or less than 0.1 wt%.

5. The water-washing solid-liquid separation method as described in any one of paragraphs 1 to 4, wherein the solid-containing Fischer-Tropsch synthesis product is selected from Fischer-Tropsch synthesis oil phase products, purified crude oil, atmospheric pressure heavy oil, or crude Fischer-Tropsch synthesis products obtained by filtering and separating the solid-containing Fischer-Tropsch synthesis products generated by a slurry bed Fischer-Tropsch synthesis reactor.

6. The water-washing solid-liquid separation method according to paragraph 5, wherein the Fischer-Tropsch synthesis oil phase product is selected from Fischer-Tropsch synthesis light oil having an initial boiling point of 80 ℃ or lower, Fischer-Tropsch synthesis heavy oil having an initial boiling point of 100 ℃ or higher, Fischer-Tropsch synthesis wax having a freezing point of higher than 100 ℃, filter wax and/or stabilizer wax.

7. The aqueous washing solid-liquid separation method of any one of paragraphs 1 to 6, wherein the solid particles in the solid-containing Fischer-Tropsch synthesis product have a particle size of 0.1 to 500 μm.

8. The aqueous washing solid-liquid separation method of any one of paragraphs 1 to 7, wherein the water is desalted water, deionized water and/or Fischer-Tropsch synthesis water.

9. The aqueous wash solid-liquid separation method of any of paragraphs 1 to 8, wherein an acidic material is added to the water prior to mixing the solid fischer-tropsch synthesis product with the water.

10. The aqueous wash solid-liquid separation method of paragraph 9 wherein the acidic material is selected from hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, oleic acid, stearic acid or any mixture thereof.

11. The water wash solid-liquid separation method of any one of paragraphs 1 to 10, wherein a surfactant, a flocculant, a corrosion and scale inhibitor, a dispersant and/or a precipitant are added to the water before the solid-containing fischer-tropsch synthesis product is mixed with the water.

12. The aqueous wash solid-liquid separation process of paragraph 11 wherein the surfactant is selected from methyl stearate, methyl oleate and/or methyl palmitate; the flocculant is selected from polyacrylamide, amino ethyl acrylic acid and/or polyaluminium chloride; the corrosion and scale inhibitor is selected from hydroxyethylidene diphosphonic acid, 2-acrylamide-2-methylpropanesulfonic acid, 2-phosphate-1, 2, 4-tricarboxylic acid butane and/or 2-hydroxyphosphonoacetic acid; the dispersant is selected from polyaspartic acid, polyepoxysuccinic acid and/or polymaleic acid; the precipitant is selected from palmitic acid and/or SA-20.

13. The water-washing solid-liquid separation method according to any one of paragraphs 1 to 12, wherein the solid-containing fischer-tropsch synthesis product is mixed with the water at a mass ratio of 1:20 to 20: 1.

14. The aqueous wash solid-liquid separation method of any of paragraphs 1 to 13, wherein the solid-containing fischer-tropsch synthesis product is mixed with the water at a temperature between the freezing point and the boiling point of the solid-containing fischer-tropsch synthesis product.

15. The aqueous washing solid-liquid separation method of paragraph 14, wherein the mixing is carried out at a temperature at which the viscosity of the solid-containing Fischer-Tropsch synthesis product is 0 to 10 mPas.

16. The aqueous washing solid-liquid separation method of paragraph 15 wherein the mixing is carried out at a temperature of 60 to 260 ℃.

17. The water-washing solid-liquid separation method according to any one of paragraphs 1 to 16, wherein the mixing pressure is 0 to 5 MPaG.

18. The aqueous wash solid-liquid separation method of any of paragraphs 1 to 17, wherein steam, N, is introduced when mixing the solid-containing fischer-tropsch synthesis product with the water₂And/or an inert gas.

19. The aqueous wash solid-liquid separation method of any of paragraphs 1-18, wherein the mixing is performed using one or more equipment selected from the group consisting of: a kettle reactor, a static mixer, a pipeline type ultrahigh-speed emulsifying machine and an intermittent emulsifying kettle.

20. The water-washing solid-liquid separation method according to any one of paragraphs 1 to 19, wherein the solid-containing fischer-tropsch synthesis product is separated from the water mixture after mixing the solid-containing fischer-tropsch synthesis product with the water for 10 to 30 minutes.

21. The aqueous wash solid-liquid separation method of any one of paragraphs 1 to 20, wherein the solid-containing fischer-tropsch synthesis product is separated from the aqueous mixture by one or more means selected from: filtering, settling, cyclone separation or centrifugal separation.

22. The aqueous wash solid-liquid separation method of any of paragraphs 1-21, wherein the method further comprises: before step (1), the solid-containing Fischer-Tropsch synthesis product and the water are respectively fed after being buffered.

23. The aqueous wash solid-liquid separation method of any of paragraphs 1-22, wherein the method further comprises: heat exchanging the solid-containing fischer-tropsch synthesis product with the water prior to step (1).

24. The aqueous wash solid-liquid separation process of paragraph 23 wherein said heat exchange is carried out by steam heating or electrical heating.

25. The aqueous wash solid-liquid separation method of paragraph 23 or 24 wherein the method further comprises: before the step (1), carrying out heat preservation and heat tracing treatment on the solid-containing Fischer-Tropsch synthesis product after heat exchange and water.

26. The aqueous wash solid-liquid separation method of any of paragraphs 1-25, wherein the method further comprises: and carrying out oil-water separation on the solid-containing water phase to obtain oil-removing Fischer-Tropsch synthetic water and solid-containing emulsified oil.

27. The water wash solid-liquid separation method of paragraph 26 wherein a portion of the deoiled fischer-tropsch synthesis water is returned to step (1) for use in the mixing and the remaining portion of the deoiled fischer-tropsch synthesis water is subjected to downstream water treatment.

28. The water-wash solid-liquid separation process of paragraph 26 or 27 wherein the solids-containing emulsified oil is returned to step (1) for use in the mixing.

29. The aqueous wash solid-liquid separation method of any of paragraphs 1-28, wherein the method further comprises: and carrying out flash evaporation treatment on the Fischer-Tropsch synthesis product subjected to solid removal to obtain a flash evaporated Fischer-Tropsch synthesis product and non-condensable gas.

30. The aqueous wash solid-liquid separation method of any of paragraphs 1 to 29, wherein the method comprises the steps of:

(i) respectively buffering the solid Fischer-Tropsch synthesis product and the water and then feeding;

(ii) carrying out heat exchange on the fed solid-containing Fischer-Tropsch synthesis product and water;

(iii) mixing the solid Fischer-Tropsch synthesis product subjected to heat exchange with water to obtain a mixture of the solid Fischer-Tropsch synthesis product and the water;

(iv) carrying out cyclone separation on the solid-containing Fischer-Tropsch synthesis product and a water mixture to obtain the solid-removed Fischer-Tropsch synthesis product and the solid-containing water phase;

(v) (iv) subjecting the Fischer-Tropsch synthesis product subjected to solid removal to flash evaporation treatment to obtain a flash evaporated Fischer-Tropsch synthesis product and non-condensable gas, and returning part of the flash evaporated Fischer-Tropsch synthesis product to the step (iii) for mixing; and

(vi) carrying out cyclone separation on the solid-containing water phase to obtain oil-removing Fischer-Tropsch synthetic water and solid-containing emulsified oil; (iv) returning a portion of the deoiled fischer-tropsch synthesis water to step (iii) for use in the mixing, and subjecting the remaining portion of the deoiled fischer-tropsch synthesis water to downstream water treatment; optionally, the solids-containing emulsified oil is returned to step (iii) for use in the mixing.

31. A system for carrying out the aqueous wash solid-liquid separation method of any one of paragraphs 1-30, wherein the system comprises:

an oil-water mixing device;

an oil-water separator connected in fluid communication to the oil-water mixing device.

32. The system of paragraph 31 wherein the system further comprises a solid fischer-tropsch synthesis product containing surge tank and a water surge tank.

33. The system of paragraph 31 or 32, wherein the system further comprises a heat exchanger.

34. A system as paragraph 33 recites, wherein the heat exchanger is a tube and/or plate heat exchanger.

35. The system of any of paragraphs 31-34, wherein the system further comprises a heat tracing apparatus.

36. The system of any of paragraphs 31-35, wherein the system further comprises a fischer-tropsch synthesis product collection tank.

37. The system of any of paragraphs 31-36, wherein the system further comprises a flash separation tank.

38. The system of any of paragraphs 31-37, wherein said system further comprises a waste water collection tank.

39. The system of any of paragraphs 31-38, wherein said system further comprises an emulsified oil mixed liquor collection tank.

40. The system of any of paragraphs 31-39, wherein the oil-water mixing device is a tank reactor, a static mixer, a pipeline ultra-high speed emulsification machine, or a batch emulsification tank.

41. The system of any of paragraphs 31-40, wherein said oil-water separation device is a cyclonic oil-water separation tank.

Next, the scheme of the present invention will be further exemplarily described with reference to fig. 2. The solid Fischer-Tropsch synthesis product 101 with low solid content enters the Fischer-Tropsch synthesis product buffer tank 1, and the Fischer-Tropsch synthesis water 104 enters the water buffer tank 2. The Fischer-Tropsch synthesis product stream 102 and the Fischer-Tropsch synthesis water stream 105 which are fed into respective buffer tanks are subjected to heat exchange through a heat exchanger 9 and a heat exchanger 10 respectively, and then solid Fischer-Tropsch synthesis products and synthesis water mixed front streams 107 from the Fischer-Tropsch synthesis product stream 103 and the Fischer-Tropsch synthesis water stream 106 which are subjected to heat exchange enter a static mixer 3 to obtain an oil-water mixed product stream 108. Carrying out cyclone separation on the oil-water mixed product stream 108 through a cyclone oil-water separation tank 4 to obtain a solidified Fischer-Tropsch synthesis product stream 109 at the top of a cyclone separator in the cyclone oil-water separation tank 4; and a solid-containing water phase is obtained at the bottom of the cyclone separator in the cyclone oil-water separation tank 4.

The fischer-tropsch synthesis product 109 after solids removal firstly enters a product collection tank 5, then a product stream 110 from the product collection tank enters a flash separation tank 6 for water removal to obtain a fischer-tropsch synthesis product 111 after flash evaporation and non-condensable gas 112, the non-condensable gas 112 is released to a vent system, and a solid removal product with an unqualified solid content at the initial start-up and a stream (namely, a stream of partial solid removal product) 119 serving as a dilution stream during full-load operation also enter a mixed liquid collection tank 8. And returning one part of the flashed Fischer-Tropsch synthesis product 111 serving as a solid removal Fischer-Tropsch synthesis product stream 118 to the inlet of the static mixer 3 to be mixed with the heat-exchanged Fischer-Tropsch synthesis product stream 103, and pumping and pressurizing the remaining part of the flashed Fischer-Tropsch synthesis product by using a pump to serve as a pressurized stream 113 to enter a product tank.

Further carrying out oil-water separation on the solid-containing water phase in a cyclone oil-water separation tank 4 to obtain an oil-removing Fischer-Tropsch synthesis water stream 114 and a solid-containing emulsified oil stream 115; the deoiled Fischer-Tropsch synthesis water stream 114 enters a waste water collecting tank 7 to obtain a stream 116 from the waste water collecting tank, and a part of the stream 116 serving as a stream 117 to be subjected to water treatment can directly enter a downstream water treatment system; and mixing the stream 119 of the diluted stream with the stream 115 containing solid emulsified oil and the other part of the stream 116 in an emulsified oil mixed liquid collecting tank 8, diluting the solid content to meet the feeding requirement of the system, returning the diluted solid content and the emulsified oil mixed liquid to the static mixer 3, and performing secondary or multiple times of water washing after heat exchange by a heat exchanger.