JP5294662B2 - Method for selective removal of finely divided FT catalyst in FT synthetic oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in that although a residual catalyst contained in an Ft synthetic crude oil is recovered and reused and also the synthetic oil with reduced residual catalyst is obtained, since the catalyst is pulverized, it has a bad influence for the characteristics of reactivity, etc., of the synthesis. <P>SOLUTION: By making the magnetic separation process as 2 stage separation processes, in a first liquid solid separation process, the catalyst having a large particle diameter is recovered and reused, and in a second liquid solid separation process, the pulverized residual catalyst is separated and discharged to the outside of a system. Thus, the FT synthetic oil reduced with the residual catalyst is obtained. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  In the present invention, a slurry comprising a synthetic oil obtained by a Fischer-Tropsch synthesis method (hereinafter abbreviated as “FT synthesis method”) using carbon monoxide and hydrogen as raw materials and a magnetic Fischer-Tropsch catalyst is removed from a reactor. The catalyst having a large particle size in the slurry is separated and circulated into the reactor, and the catalyst having a small particle size is discharged out of the system and the obtained synthetic oil is recovered in order to recover the obtained synthetic oil. It is related with the method of processing by the liquid-solid separation process of at least 2 step | paragraph containing.

  In recent years, clean liquid fuels that are low in sulfur content and aromatic hydrocarbon content and that are friendly to the environment have been demanded from the viewpoint of reducing environmental impact. Therefore, in the petroleum industry, an FT synthesis method using carbon monoxide and hydrogen as raw materials is being studied as a method for producing clean fuel. According to the FT synthesis method, a liquid fuel base material having a high paraffin content and not containing a sulfur content, for example, a diesel fuel base material can be produced. For example, environmentally-friendly fuel oil is also proposed in Patent Document 1.

JP 2004-323626 A

On the other hand, FT synthesis catalysts using carbon monoxide and hydrogen as raw materials have hitherto been many iron-based solid catalysts, but recently, cobalt-based solid catalysts have also been developed because of their high activity.
Here, the reaction form of the FT synthesis method is often an embodiment of a slurry in which a solid catalyst is suspended in a product hydrocarbon. Therefore, in addition to obtaining a synthetic oil containing no catalyst, it is necessary to recover and reuse the catalyst in the resulting FT synthesis slurry from the viewpoint of cost reduction of the process.

Since a slurry in which the catalyst is suspended is obtained from the reactor for FT synthesis, it is preferable to recover the catalyst from this and reuse it, while recovering the synthetic oil containing no catalyst.
In the reactor for FT synthesis, the catalyst may repeatedly collide, pulverize, etc., and become fine particles, and the flow state in the FT synthesis reactor may change.
On the other hand, the liquid-solid separation step is generally a mechanism that separates and removes particles having a particle diameter of a predetermined diameter or more, and therefore, a certain finely divided material easily passes through the separation step. In this way, the pulverized catalyst that easily passes through the separation step selectively and actively removes the catalyst in order to maintain the flow state in the reactor and to reduce the residual catalyst in the synthetic oil. There is a need.

  The present inventors can separate the first separation step by reusing the FT synthesis slurry by at least a first liquid-solid separation step including a magnetic separation step and a subsequent second liquid-solid separation step. A catalyst with a large particle size is recovered and reused. In the second liquid-solid separation step, the pulverized catalyst is separated and removed using a high degree of separation operation. Thus, FT synthetic oil with reduced residual catalyst is recovered.

That is, in the first aspect of the present invention, a slurry containing a synthetic oil obtained by the Fischer-Tropsch method and a magnetic Fischer-Tropsch catalyst is extracted from a Fischer-Tropsch synthesis reactor, and a catalyst having a large particle size in the slurry is separated. The slurry is then circulated through the reactor, the catalyst having a small particle size is discharged out of the system, and the slurry is treated by at least two liquid-solid separation processes including a magnetic separation process in order to recover the synthetic oil obtained. And then where
The first liquid-solid separation step is a magnetic separation step, in the process, the catalyst separation of predetermined diameter from the slurry and collected, which is reused by circulating the Fischer-Tropsch reactor, high The separation conditions of the gradient magnetic separator are as follows: the magnetic field strength is 2000 gauss to 4000 gauss, the processing temperature is 100 ° C. to 400 ° C., and the residence time is 15 seconds or more.
The second liquid-solid separation step is a liquid-solid separation step other than magnetic separation, in which the average particle size is greater than the average particle size of the catalyst in the slurry at the outlet of the Fischer-Tropsch reactor. Is also characterized by separating the small catalyst, which is discharged outside the system and recovering the resulting synthetic oil,
The present invention relates to a method for selectively removing a Fischer-Tropsch catalyst having a reduced particle size from a reactor.

According to a second aspect of the present invention, in the first aspect of the present invention, the high gradient magnetic separator has a cleaning liquid introduction line for cleaning the inside and a line for discharging the cleaning liquid, and intermittently captures the captured magnetic fine particles. It relates to a method of cleaning.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the liquid-solid separator selected from other than the high gradient magnetic separator is at least a filtration separator, a gravity sedimentation separator, a cyclone, or a centrifuge. It is related with the method characterized by being one.

  In the treatment of the slurry from the FT reactor, a multi-stage separation step is provided, from which the catalyst having an effective particle size is recovered in the first treatment stage, which is returned to the FT reactor and reused. In the latter stage, FT synthetic oil with reduced catalyst residue is recovered by removing the finely divided catalyst. Further, by using the magnetic separation step in combination, the finely divided catalyst can be efficiently recovered from the FT synthetic crude oil in which fine fine particles are easily generated.

The present invention is described in detail below.
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, a synthesis gas containing carbon monoxide gas and hydrogen gas is supplied from a line 1, and liquid hydrocarbons are generated by an FT synthesis reaction in an FT synthesis reactor 10. The synthesis gas can be obtained by, for example, hydrocarbon reforming as appropriate. Typical hydrocarbons include methane, natural gas, LNG (liquefied natural gas), and the like. For example, a partial oxidation reforming method (POX) using oxygen, an autothermal reforming method (ATR) that is a combination of the partial oxidation reforming method and the steam reforming method, a carbon dioxide gas reforming method, or the like can be used. .

Next, FT synthesis will be further described with reference to FIG.
FT synthesis comprises an FT synthesis reactor 10. The reactor 10 can be, for example, a bubble column reactor, which is an example of a reactor that synthesizes synthesis gas into liquid hydrocarbons, and synthesizes liquid hydrocarbons from synthesis gas by an FT synthesis reaction. Functions as a reactor for FT synthesis.

The main body of the reactor 10 is a substantially cylindrical metal container having a diameter of about 1 to 20 m, preferably about 2 to 10 m. The height of the reactor body is about 10 to 50 m, preferably about 15 to 45 m. Inside the reactor main body, a slurry in which solid catalyst particles are suspended in liquid hydrocarbon (product of FT synthesis reaction) is accommodated.
Part of the slurry is discharged from the middle of the reactor to the separators 20 and 30 via the line 3. From the top of the reactor 10, unreacted synthesis gas or the like is discharged through the line 2, and a part of it is returned to the line 1 and circulated through the reactor 10 as appropriate.

  The synthesis gas supplied from the outside through the synthesis gas supply pipe 1 is injected into the slurry inside the reactor 10 from a synthesis gas supply port (not shown). The synthesis gas undergoes a liquid hydrocarbon synthesis reaction (FT synthesis reaction) by a contact reaction that contacts catalyst particles. Specifically, as shown in the chemical reaction formula (1) below, hydrogen gas and carbon monoxide gas cause a synthesis reaction.

2nH ₂ ten _{nCO → (-CH 2 -) n} + nH 2 0. . . . (1)

Specifically, synthesis gas is introduced from the line 1 to the bottom of the reactor 10 to raise the slurry stored in the reactor 10. At this time, in the reactor, carbon monoxide and hydrogen gas contained in the synthesis gas react by the above-described FT synthesis reaction to generate hydrocarbons. Although heat is generated during this synthesis reaction, the heat is removed by an appropriate cooling means.
The metal catalyst includes a supported type and a deposited type, but in any case, it is a solid particle containing an iron group metal. An appropriate amount of metal is contained in the solid particles, but 100% metal may be used. The iron group metal is exemplified by iron, and cobalt is preferable from the viewpoint of high activity.

The composition ratio of the synthesis gas supplied to the FT synthesis reactor 10 is adjusted to a composition ratio (for example, H ₂ : CO = 2: 1 (molar ratio)) suitable for the FT synthesis reaction. In addition, the synthesis gas supplied to the reactor 10 is pressurized to a pressure (for example, 3.6 MPaG) appropriate for the FT synthesis reaction by an appropriate compressor (not shown). However, the compressor may not be provided.

  Thus, the liquid hydrocarbon synthesized in the reactor 10 is taken out from the reactor 10 through the line 3 as a slurry in which catalyst particles are suspended from the line 3 in the middle of the reactor 10, and used for the catalyst separation and recovery process. Is done.

In the catalyst separation and recovery process, as shown in the figure, two separators 20 and 30 are arranged in series.
In the first liquid-solid separation step by the separator 20, a catalyst having a predetermined diameter is separated and recovered from the slurry, which is circulated from the line 21 to the Fischer-Tropsch reactor 10 and reused.
The predetermined diameter can be set as appropriate. For example, the catalyst particle diameter (prepared diameter) at the initial stage of the reaction or the particle diameter that decreases with time can be set as appropriate. In short, a catalyst having a predetermined diameter is appropriately set from the viewpoint of returning to the reaction system and reusing it.

Since the catalyst separated and recovered from the first separator 20 has a large particle size and can be reused in the FT reactor 10, it is returned to the reaction system by the line 21 and reused.
The remaining slurry from which the large particles have been separated and removed is then sent to the next separator 30 via the line 22.

  In the first liquid-solid separation step, an effective and usable catalyst is separated and recovered, and the catalyst remaining in the liquid is an unnecessary catalyst having a small particle size. It is removed in the separation step. Specifically, the catalyst having an average particle size of the catalyst discharged in the second liquid-solid separation step is separated from the average particle size of the catalyst in the slurry at the Fischer-Tropsch reactor outlet, The resulting synthetic oil can be recovered from the line 32.

Since the catalyst separated and recovered from the next separator 30 is pulverized, it is discharged out of the reaction system and disposed of without being reused.
Either or both of the separators 20 and 30 can be used as magnetic separation means. First, the case where the liquid-solid separator 20 is used as magnetic separation means will be described below.

  Hereinafter, the separation operation by the high gradient magnetic separator 20 will be described. In this step, the magnetic fine particles contained in the extracted FT synthetic crude oil are separated and removed by the high gradient magnetic separator 20.

  That is, the FT synthetic crude oil is processed by the high gradient magnetic separator 20 to separate and remove the magnetic fine particles. It has also been found that the iron group metal as the FT synthesis catalyst has a certain magnetic susceptibility and exhibits paramagnetism, whether iron or cobalt. Therefore, removal by magnetic separation is quite effective.

  The high gradient magnetic separator 20 used in the present invention has a ferromagnetic packing disposed in a uniform high magnetic field space generated by an external electromagnetic coil, and is usually 1 to 20 k gauss / cm generated around the packing. It is a magnetic separator designed to attach ferromagnetic or paramagnetic particulate matter to the surface of the packing by a high magnetic field gradient, separate them, and wash the attached particles. For example, as the high gradient magnetic separator, a commercially available machine known by a registered trademark “FEROSEP” or the like can be used.

  As the ferromagnetic filler, an aggregate of ferromagnetic fine wires such as steel wool or steel net having a diameter of 1 to 1000 μm, expanded metal, and shell-shaped metal strips are usually used. As the metal, stainless steel having excellent corrosion resistance, heat resistance and strength is preferable.

  In addition, as proposed in JP-A-7-70568, a ferromagnetic metal piece is a plate-like body having two surfaces, and the area of the larger surface of the two surfaces is the diameter. R = equal to the area of a circle of 0.5 to 4 mm, the ratio of R to the maximum thickness d of the plate, R / d is in the range of 5 to 20, and the plate is mainly made of Fe A ferromagnetic metal piece made of an Fe—Cr alloy containing 5 to 25 wt% of Cr, 0.5 to 2 wt% of Si, and 2 wt% or less of C as components can also be preferably used.

  In the step of separating the magnetic fine particles in the slurry by the high gradient magnetic separator 20, the slurry is introduced into the magnetic field space of the high gradient magnetic separator 20, and the magnetic fine particles are put into the ferromagnetic packing placed in the magnetic field space. Deposit and remove from slurry. Next, the step of washing and removing the magnetic fine particles adhering to the packing has a limit in the amount of magnetic fine particles to be trapped by the packing of a certain area, and the trapping is performed when the trapped amount reaches a certain amount or the limit amount. The magnetic fine particles are washed away from the packing. This washing and removing step is performed by cutting off the magnetic field to desorb the magnetic fine particles, and discharging the magnetic fine particles outside the magnetic separator with the washing liquid. The magnetic separation conditions for the magnetic fine particles contained in the slurry and the washing and removal conditions for the magnetic fine particles trapped and adhered to the packing will be described below.

  As a separation condition of the high gradient magnetic separator 20, the magnetic field strength is preferably 2000 gauss or more, and more preferably 3000 gauss or more. The liquid temperature (treatment temperature) in the separator is preferably from 100 ° C. to 400 ° C., more preferably from 100 ° C. to 300 ° C., particularly preferably from 100 ° C. to 200 ° C. The liquid residence time (residence time) is preferably 15 seconds or longer, and more preferably 20 seconds or longer.

  Next, if the magnetic separation operation of the magnetic fine particles is continued, the removal rate decreases as the amount of the magnetic fine particles trapped in the packing increases. Therefore, in order to maintain the removal rate, it is necessary to perform a washing and removing step of discharging the captured magnetic fine particles to the outside of the magnetic separator after passing oil for a certain time. In actual industrial operation, the liquid fraction containing magnetic fine particles may bypass the magnetic separator during this washing and removing process. However, if the time required for washing is long, the amount of magnetic fine particles flowing into the next process increases. Since the removal rate is lowered, a preliminary separator for switching may be provided if necessary.

  In washing and removing, in the present invention, the treated oil after being treated by magnetic separation can be used as a washing liquid.

  In the washing and removing step, the magnetic field around the packing is lost (the power supply to the magnetic coil for the magnetic separator is stopped), and the cleaning liquid is introduced from the bottom of the separator tower via the line 24 and is simply attached to the packing. This is an operation to wash away magnetic fine particles. The cleaning liquid is discharged from the line 25. As cleaning conditions, the cleaning liquid linear velocity is 1 to 10 cm / sec, preferably 2 to 6 cm / sec.

The magnetic separation process will be described below with reference to FIG.
FIG. 2 is a schematic simplified view of the high gradient magnetic separator 20 used in the present invention. The separation part of the high gradient magnetic separator 20 forms a vertical packed tower and is filled with a ferromagnetic packing. The packed bed 22 filled with the packing is magnetized by the magnetic lines generated by the electromagnetic coil 23 outside the tower to form a high gradient magnetic separation part. This portion is a uniform high magnetic field space generated by the external electromagnetic coil. The slurry heated to an appropriate temperature passes through the separation part from the line 3 from the bottom to the top at a predetermined flow rate and a liquid residence time of 15 seconds or more. During this time, magnetic fine particles adhere to the surface of the packing and are removed. It is burned.

  While the FT synthetic crude oil passes through the magnetic separator 20, the cleaning liquid bypasses through a cleaning oil bypass line (not shown), the cleaning liquid cleans the magnetic separator 20 from the line 24, and the cleaning liquid is extracted from the line 25. When discharged, the slurry can be bypassed through a slurry bypass line (not shown) and directly sent to a subsequent liquid-solid separation device, for example, the separator 30. In this way, it is possible to perform switching between removal operation, cleaning operation, and repeated continuous operation. The washing and removing step can be performed with reference to the method described in JP-A-6-200260.

  Subsequent to the magnetic separator 20, a separate liquid-solid separation step 30 other than the magnetic separation step is provided as a second stage. Thus, in the second liquid-solid separation step, separation is performed in the first liquid-solid separation step. From the liquid, the catalyst having an average particle size smaller than the average particle size of the catalyst in the slurry at the outlet of the Fischer-Tropsch reactor was separated, and the separated catalyst was discharged out of the system. Collect the synthetic oil. The separated catalyst is discharged out of the system from the line 31, and clean FT synthetic oil with reduced catalyst residue is extracted from the line 32 and sent to the next step, for example, the rectifying column 40.

  Although there is no particular limitation on the method for measuring the average particle size, for example, an average particle size (μm) measured by a particle size distribution measuring device of a laser diffraction method, a dynamic light scattering method, or a standard sieve method can be preferably exemplified. . Further, the average particle diameter of the discarded FT catalyst is not particularly limited as long as it is smaller than the average particle diameter of the FT catalyst in the slurry at the FT reactor outlet. The average particle size of the FT catalyst is preferably 5% or more, more preferably 10% or more, and further preferably 20% or more. Although a lower limit is not specifically limited, Usually, it depends on the separation ability in the second-stage liquid-solid separation step.

  The separate liquid-solid separation step 30 other than the magnetic separator in the second stage is selected from a filter using an appropriate filter such as a sintered metal filter, a gravity sedimentation separator, a cyclone, a centrifuge, etc. Ordinary ones can also be used. For example, it is possible to use a sedimentation tank (gravity sedimentation separator / natural sedimentation system) that fills the liquid and leaves the solid particles in the liquid for a certain period of time to spontaneously settle. A natural sedimentation type gravity sedimentation separator is advantageous because of its simple structure. These can be used either continuously or batchwise.

  In the above description, a combination in which a magnetic separator is used for the first-stage separator 20 and a separate liquid-solid separator other than the magnetic separator is used for the subsequent second-stage separator 30 is shown. However, the present invention is not limited to this, and conversely, a combination using a separation unit using a liquid-solid separator other than the magnetic separator for the first-stage separator 20 and a magnetic separator for the second-stage separator 30 is adopted. Can do.

Referring again to FIG. 1, the FT synthetic crude oil from which the magnetic fine particles have been separated by the two separators 20 and 30 is sent to the rectification tower 40 through the line 32, where it is rectified, hydrotreated, etc. Various purification treatments are applied to produce a product.
That is, the liquid obtained through the two-stage liquid-solid separation step is put into the rectification column 40 and fractionated. For example, the naphtha fraction (boiling point is less than 150 ° C.) is separated by an intermediate distillation by a line 41. A fraction (boiling point 150 to 350 ° C.) is fractionated by line 42, and a wax fraction (boiling point 350 ° C. or higher) is fractionated by line 43. Although it is fractionated into 3 fractions in the figure, it may be 2 fractions or 3 fractions or more. Moreover, it can also use for the following appropriate refinement | purification processes, without being especially distilled.

  The present invention provides a catalyst having a large particle size by separating magnetic fine particles as residual catalyst contained in an FT synthetic crude oil obtained by an FT synthesis method using carbon monoxide and hydrogen as raw materials by a two-stage liquid-solid separator. The catalyst which is effectively recovered, reused and pulverized can be discharged out of the system and thus used in a method for producing a clean FT synthetic oil with reduced catalyst residues.

Syngas containing carbon monoxide and hydrogen gas obtained by reforming natural gas as main components is sent to a bubble column type hydrocarbon synthesis reactor (FT synthesis reactor) 10 and FT catalyst particles (average) Liquid hydrocarbons are synthesized by reaction in a slurry in which a particle size of 100 μm and cobalt as an active metal is supported by 30% by weight.
The liquid hydrocarbon synthesized by the FT synthesis reaction is taken out from the line 3 as a slurry containing FT catalyst particles.

  The taken slurry was led to a first liquid-solid separation step (electromagnet type high gradient magnetic separator (FEROSEP (registered trademark))) 20 arranged in the latter stage of the FT synthesis reactor, and a part of the treatment conditions described in Table 1 were used. The catalyst particles (particles having a relatively large particle size) are separated into a liquid component (liquid A) containing catalyst particles that could not be captured by the high gradient magnetic separator 20.

The catalyst particles separated in the first liquid-solid separation step 20 are returned to the FT synthesis reactor 10 from the line 21, and the liquid component (liquid A) is the second liquid-solid separation step (sintered with an opening of 10 μm). It is led to a (metal filter) 30 and further separated into solid catalyst particles and liquid (liquid B).
The FEROSEP used in the first liquid-solid separation step 20 has a cleaning introduction line 24 for internal cleaning and a line 25 for discharging the cleaning liquid, and the captured catalyst particles are intermittently cleaned at intervals of 2 hours. And returned to the FT synthesis reactor.

  The catalyst particles separated in the second liquid-solid separation step 30 are discharged to the outside of the system, and the liquid component (liquid B) is guided to the rectification column 40 and fractionated, and a naphtha fraction (boiling point is reduced to a line 41). In the middle fraction (boiling point 150 to 350 ° C.) as line 42, and in the wax fraction (boiling point 350 ° C. or higher) as line 43. Further, the middle fraction is treated with a hydroisomerization apparatus (not shown), and the wax fraction is treated with a hydrocracking apparatus (not shown), and then line blended to produce a second fractionator (not shown). ) And fractionated to obtain a diesel fuel base material.

At this time, the average particle diameter of the catalyst particles in the slurry at the outlet of the FT reactor 10 was 72.5 μm, and the average particle diameter of the catalyst particles discharged out of the system was 57 μm.
Here, the average particle diameter of the catalyst particles is a value based on the measurement result of a laser diffraction particle size distribution analyzer SALD-3100 manufactured by Shimadzu Corporation (the same applies hereinafter).

  The same treatment as in Example 1 was performed except that the treatment conditions of the first liquid-solid separation step were changed as shown in Table 1. At this time, the average particle diameter of the catalyst particles discharged out of the system was 28 μm.

  The same treatment as in Example 1 was performed except that the treatment conditions of the first liquid-solid separation step were changed as shown in Table 1. At this time, the average particle diameter of the catalyst particles discharged out of the system was 39 μm.

  The same treatment as in Example 1 was performed except that the treatment conditions of the first liquid-solid separation step were changed as shown in Table 1. At this time, the average particle diameter of the catalyst particles discharged out of the system was 25 μm.

  Syngas containing carbon monoxide and hydrogen gas obtained by reforming natural gas as main components flows into a bubble column type hydrocarbon synthesis reactor (FT synthesis reactor) 10 and FT catalyst particles (average particles) Liquid hydrocarbons are synthesized by reacting in a slurry in which 100 μm in diameter and 30% by weight of cobalt as an active metal are suspended. The liquid hydrocarbon synthesized in the FT synthesis reactor 10 is taken out from the line 3 as a slurry containing FT catalyst particles. Liquid component (Liquid A) containing part of the catalyst particles (particles having a relatively large particle size) and catalyst particles that could not be captured in the first liquid-solid separation step And to separate. The catalyst particles separated in the first liquid-solid separation step are returned to the FT synthesis reactor 10, and the liquid component (liquid A) is continued in the second liquid-solid separation step (electromagnetic type high gradient magnetic separator (FEROSEP ( (Registered Trademark)))) 30 and further separated into solid catalyst particles and liquid (liquid B).

  The high gradient magnetic separator 30 used in the second liquid-solid separation step has a cleaning introduction line 24 for internal cleaning and a line 25 for discharging the cleaning liquid, and captures the captured catalyst particles at intervals of 2 hours. It is intermittently washed and discharged out of the system. The catalyst particles separated in the second liquid-solid separation step 30 are discharged out of the system, and the liquid component (liquid B) is guided to the rectification column 40 and fractionated, and the naphtha fraction (boiling point is less than 150 ° C.). ) 41, middle distillate (boiling point 150-350 ° C.) 42 and wax fraction (boiling point 350 ° C. or higher) 43. Further, the middle fraction is treated with a hydroisomerization apparatus (not shown), and the wax fraction is treated with a hydrocracking apparatus (not shown), and then line blended to produce a second fractionator (not shown). ) And fractionated to obtain a diesel fuel base material. At this time, the average particle diameter of the catalyst particles in the slurry at the outlet of the FT reactor 10 was 72.5 μm, and the average particle diameter of the catalyst particles discharged out of the system was 25 μm.

[Comparative Example 1]
A synthesis gas containing carbon monoxide and hydrogen gas obtained by reforming natural gas as main components is caused to flow into a bubble column type hydrocarbon synthesis reactor (FT synthesis reactor) 10 and FT catalyst particles (average particles). Liquid hydrocarbons were synthesized by reaction in a slurry in which 100 μm in diameter and 30% by weight of cobalt as an active metal was suspended. The liquid hydrocarbon synthesized in the FT synthesis reactor 10 is taken out from the line 3 as a slurry containing FT catalyst particles, and the taken slurry is a single-stage liquid-solid separation step (opening) Is 10 μm sintered metal filter) 20 and separated into catalyst particles and a liquid component. Here, the liquid-solid separator 20 is a single stage, and the magnetic separator 30 is not provided.

  Here, the catalyst particles separated in the liquid-solid separation step 20 are discharged out of the system, and the liquid component is guided to the rectification column 40 and fractionated to obtain a naphtha fraction (boiling point less than 150 ° C.) 41, intermediate A fraction (boiling point: 150 to 350 ° C.) 42 and a wax fraction (boiling point: 350 ° C. or higher) 43 were fractionated. At this time, the average particle diameter of the catalyst particles discharged out of the system was 72.5 μm.

(result)
When the electromagnet type high gradient magnetic separator 20 is arranged as the first liquid-solid separation step and the metal filter 30 is arranged as the second liquid-solid separation step in the subsequent stage of the FT synthesis reactor (Examples 1 to 4), and When the metal filter 20 is arranged as the first liquid-solid separation step and the electromagnet type high gradient magnetic separator 30 is arranged as the second liquid-solid separation step, the average particle diameter (weight basis) of the catalyst discharged out of the system Shows a smaller value than the comparative example, and it can be seen that the catalyst particles having a reduced particle size can be selectively removed from the slurry.

A fuel production plant including an FT synthesis reactor 10, a liquid-solid separator 20 using a magnetic separator that magnetically separates magnetic fine particles in FT synthetic crude oil, and a liquid-solid separator 30 other than the magnetic separator. It is a model schematic diagram of the high gradient magnetic separator 20 used for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 FT synthesis reactor 20 Magnetic separator 30 Liquid-solid separator other than magnetic separator 40 First rectification column for fractionating FT synthetic crude oil

Claims (3)

A slurry containing a synthetic oil obtained by the Fischer-Tropsch process and a magnetic Fischer-Tropsch catalyst is extracted from a Fischer-Tropsch synthesis reactor, and a catalyst having a large particle size in the slurry is separated and recycled to the reactor. In order to discharge the catalyst having a small diameter out of the system and collect the resultant synthetic oil, the slurry is treated by a liquid-solid separation process including at least two stages including a magnetic separation process.
The first liquid-solid separation step is a magnetic separation step, in the process, the catalyst separation of predetermined diameter from the slurry and collected, which is reused by circulating the Fischer-Tropsch reactor, high The separation conditions of the gradient magnetic separator are as follows: the magnetic field strength is 2000 gauss to 4000 gauss, the processing temperature is 100 ° C. to 400 ° C., and the residence time is 15 seconds or more.
The second liquid-solid separation step is a liquid-solid separation step other than magnetic separation, in which the average particle size is greater than the average particle size of the catalyst in the slurry at the outlet of the Fischer-Tropsch reactor. Is also characterized by separating the small catalyst, which is discharged outside the system and recovering the resulting synthetic oil,
A method for selectively removing a Fischer-Tropsch catalyst having a reduced particle size from a reactor. The method according to claim 1, wherein the high gradient magnetic separator has a cleaning liquid introduction line for cleaning the inside and a line for discharging the cleaning liquid, and intermittently cleans the captured magnetic fine particles. Liquid-solid separator that is selected from other than the high gradient magnetic separator is filtered separator, gravitational sedimentation separator, and wherein the cyclone is at least one of a centrifugal separator, according to claim 1 or 2 the method of.

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