JP5223073B2 - Method for removing magnetic particles in FT synthetic oil - Google Patents

Description

  In the present invention, residual magnetic fine particles contained in FT synthetic crude oil obtained by a Fischer-Tropsch synthesis method (hereinafter abbreviated as “FT synthesis method”) using carbon monoxide and hydrogen as raw materials are reduced by hydrogen treatment. Then, it is related with the method of isolate | separating this with a magnetic separator.

  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 may be a fixed bed, a fluidized bed, a moving bed or the like, but anyway, a heterogeneous catalyst which is a solid catalyst is used.
The resulting FT synthetic crude oil contains a considerable amount of residual FT catalyst.
The resulting FT synthetic crude oil is subjected to refining treatment such as distillation and hydrotreating to become a product such as fuel oil. However, since the residual FT catalyst affects subsequent processing steps such as refining treatment, this is sufficient. Need to be removed.

Since the residual FT catalyst in the FT synthetic crude oil is often fine particles, it is advantageous to separate it by magnetic separation.
In the magnetic separation, the FT synthesis slurry is processed by a high gradient magnetic separator to separate and remove the magnetic fine particles. This method places a ferromagnetic packing in a uniform high magnetic field space generated by an external electromagnetic coil, and due to the high magnetic field gradient that usually occurs around the packing, a surface of the packing. It is a magnetic separator designed to attach a ferromagnetic or paramagnetic fine particle substance to the particle, separate them, and wash the adhered particles. Cleaning is performed by a cleaning liquid introduction line for intermittently cleaning the captured magnetic fine particles and a line for discharging the cleaned cleaning liquid.

  Since oxygen-containing compounds coexist in the slurry during the FT synthesis reaction, the active metal of the FT synthesis catalyst, such as cobalt, may be oxidized. There is a concern that cobalt has weak magnetism in an oxidized state.

  The present inventors provide a hydrogen treatment step before the magnetic separation step to bring the residual FT synthesis catalyst in an oxidized state into a reduced state, thereby strengthening the magnetism and improving the efficiency of the magnetic separation.

1st of this invention is related with the manufacturing method of FT synthetic crude oil characterized by including the process of the following (1) and (2).
(1) hydrotreating the residual FT synthesis catalyst by subjecting the slurry containing the residual FT synthesis catalyst extracted from the FT synthesis reactor to gas-liquid contact with hydrogen at 270 ° C. or higher, and (2) hydrogen A magnetic separation step of capturing and removing the treated FT synthesis catalyst from the slurry by a high gradient magnetic separator.

  According to a second aspect of the present invention, in the first aspect of the present invention, a filter may be provided at any one of the stage before the hydrotreating process, the stage between the hydrotreating process and the magnetic separation process, and the stage after the high gradient magnetic separator. Further, the present invention relates to a method for producing the synthetic crude oil, characterized by providing any liquid-solid separation step selected from the group consisting of a gravity sedimentation separator, a cyclone, and a centrifugal separator.

  A third aspect of the present invention relates to the method for producing a synthetic crude oil according to the first or second aspect of the present invention, wherein the FT synthesis catalyst removed by the high gradient magnetic separator is returned to the FT synthesis reactor.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the method further comprises a step of hydrogenating the obtained synthetic crude oil, and surplus hydrogen used in the hydrotreating step The present invention relates to a method for producing the synthetic crude oil, which is reused as part of hydrogen.

Since oxygen-containing compounds coexist in the slurry during the FT reaction, the active metal of the FT catalyst, such as cobalt, may be oxidized. Cobalt is weakly magnetized in the oxidized state, which can result in insufficient removal of the catalyst in the magnetic separator.
However, according to the present invention, the residual FT synthesis catalyst can be brought into a reduced state by performing hydrogen treatment in advance, so that the magnetic separation efficiency can be improved. As a result of the hydrogen treatment step, the FT synthesis catalyst in the FT synthesis slurry, for example, cobalt, is in a reduced state, so that the separation efficiency in the magnetic separator 40 is improved.

  Moreover, since the FT synthetic crude oil from which the residual FT synthesis catalyst has been separated and removed is often subjected to hydrorefining treatment, excess hydrogen in the hydrotreating step can be reused as hydrogen for this hydrotreating. It is advantageous.

The present invention is described in detail below. 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. 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, the FT synthesis process will be described with reference to FIG.
The FT synthesis reactor 10 is provided for the FT synthesis. 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.
From the middle of the reactor 10, a part of the slurry is discharged from the line 3 to the separator 20. From the top of the column, unreacted synthesis gas or the like is discharged in line 2, and a part thereof is appropriately circulated to the reactor.

  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, the synthesis gas flows into the bottom of the reactor 10 and raises the slurry stored in the reactor. 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. Furthermore, 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 as a slurry in which catalyst particles are suspended from the line 3 in the middle of the reactor 10 and introduced into the high gradient magnetic separator 40 via the lines 21 and 31. . In the high gradient magnetic separator 40, the taken slurry is separated into magnetic fine particles and a liquid containing liquid hydrocarbon by a magnetic separation means.
The magnetic separation process will be described below.

  That is, the FT synthetic crude oil is processed by the high gradient magnetic separator 40 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 40 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, the ferromagnetic metal piece is a plate-like body having two surfaces, and the area of the surface having the larger area of the two surfaces is The diameter R is 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-like body, R / d is in the range of 5 to 20, and the plate-like body contains Fe. A ferromagnetic metal piece made of a Fe—Cr alloy containing the main component, Cr in an amount of 5 to 25 wt%, Si in an amount of 0.5 to 2 wt%, and C in an amount of 2 wt% or less can also be preferably used.

  In the step of separating the magnetic fine particles in the liquid component introduced by the line 31 by the high gradient magnetic separator 40, the liquid component was introduced into the magnetic field space of the high gradient magnetic separator 40 and placed in the magnetic field space. Magnetic fine particles are adhered to the ferromagnetic filler and removed from the liquid introduced by the line 31. 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 of the magnetic fine particles contained in the liquid introduced by the line 31 and the cleaning removal conditions of the magnetic fine particles adhering to the packing will be described below.

  As a separation condition of the high gradient magnetic separator 40, the magnetic field strength is preferably 5000 gauss or more, more preferably 10,000 gauss or more, and particularly preferably 15000 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 10 seconds or longer, and more preferably 50 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 magnetic fine particle-containing raw material fraction may bypass the magnetic separator during this washing and removal process. However, if the time required for washing is long, the amount of magnetic fine particles flowing into the hydrotreating process is large. As a result, the removal rate is lowered, so that a preliminary separator for switching may be provided if necessary.

  In washing and removing, in the present invention, the liquid after the magnetic separation treatment (line 41) and the fraction fractionated after the magnetic separation can be used as the washing liquid.

  In the washing and removing process, the magnetic field around the packing is lost (the magnetic coil for the magnetic separator is de-energized), the cleaning liquid is introduced from the bottom of the separator through the line 38 (FIG. 2), and is simply introduced into the packing. This is an operation for removing the adhered magnetic fine particles. The cleaning liquid is discharged from the line 39 (FIG. 2). 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 separation tower 40 used in the present invention. The separation part of the high gradient magnetic separator 40 is a vertical packed tower, which is filled with a ferromagnetic packing. The packed bed 45 filled with the packing is magnetized by the magnetic field lines generated by the electromagnetic coil 46 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 liquid containing magnetic particles heated to an appropriate operating temperature passes from the line 31 through the separation section from the lower side to the upper side at a predetermined flow rate at which the liquid residence time is 10 seconds or more. It is removed by adhering.

  While the FT synthetic crude oil passes through the magnetic separator 40, the cleaning liquid is bypassed through a cleaning oil bypass line (not shown), and when the cleaning liquid is cleaning the magnetic separator 40, the liquid component is the liquid component bypass line ( It can also be bypassed through (not shown) and sent to the rectification column 50. 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.

Here, the fine particles in the FT slurry after the FT synthesis reactor are fine, and the amount thereof is large. If the particles are treated in this state in the magnetic separation step, the washing frequency of the packing is increased. As a result, magnetic separation must be complicated.
Therefore, in the embodiment of FIG. 1, although it is an optional step, a separate liquid-solid separator 20 other than the magnetic separator is provided in the preceding stage of the magnetic separator 40, thus reducing the load in the magnetic separation step. Is.

  The separate liquid-solid separation step 20 other than the magnetic separation step as a pretreatment is selected from a filter using an appropriate filter such as a sintered metal filter, a gravity sedimentation separator of a natural sedimentation method, a cyclone, a centrifuge, etc. Any of the conventional methods can be used. For example, a sedimentation tank (gravity sedimentation separator / natural sedimentation method) in which the slurry is filled and the solid particles in the slurry are allowed to settle for a certain period of time can be used. A natural sedimentation type gravity sedimentation separator is advantageous because of its simple structure. These can be used either continuously or batchwise.

An FT synthesis catalyst subjected to magnetic separation treatment, particularly a cobalt-based catalyst, has a weak magnetism in an oxidized state and may not have sufficient magnetic separation efficiency.
Therefore, in the present invention, the gas-liquid contact tower 30 that performs the hydrogen treatment to reduce the residual FT synthesis catalyst in the slurry is provided in the previous stage of the magnetic separator 40. In the embodiment shown in the figure, a gas-liquid contact tower 30 is provided between a separate liquid-solid separation step 20 other than the magnetic separation step as a pretreatment and the high gradient magnetic separator 40. In any case, the high gradient magnetic separator is provided. It may be 40 preceding stages.

The gas-liquid contact tower 30 makes the slurry containing the catalyst from the line 21 and the hydrogen from the line 32 come into gas-liquid contact in countercurrent or cocurrent, and reduces the metal in the slurry by hydrogen treatment. In order to improve the contact efficiency, it is possible to employ a packed tower packed with a packing material such as a ceramic ball or a Raschig ring. In the present invention, the hydrogen treatment temperature needs to be 270 ° C. or higher, and is preferably in the range of 300 ° C. or higher in terms of accelerating metal reduction, and in the range of 400 ° C. or lower in terms of wax content decomposition and polymerization inhibition. . Moreover, it is preferable to make LHSV into the range of 0.5-20h- ¹ .

  After hydrogen is introduced from the line 32, supplied to the gas-liquid contact tower 30 and consumed, excess hydrogen is discharged from the line 33. Excess hydrogen discharged can be used as hydrogen for the FT synthetic crude oil hydrogenation step described later. Usually, excess hydrogen is used for reduction by hydrogen treatment, so surplus hydrogen is generated. This is preferable because the surplus hydrogen can be effectively used.

  Since the metal catalyst in the FT synthesis slurry, for example, cobalt is reduced by the above-described hydrogen treatment step, the separation efficiency in the magnetic separator 40 is improved. The reduction state can be confirmed to be a predetermined reduction state by appropriately sampling the catalyst particles and measuring the magnetic susceptibility thereof. The magnetic susceptibility can be measured with a SQUID magnetometer or the like.

The FT synthetic crude oil from which the magnetic fine particles have been separated by the magnetic separator 40 is then sent to the first rectifying column 50 and rectified, and subjected to various purification processes such as hydrogenation to become a product.
That is, the liquid component obtained in the magnetic separation process 40 is inserted into the first rectification column 50 from the line 41 and fractionated. For example, the naphtha fraction (boiling point is less than 150 ° C.) in the line 53 and the intermediate in the line 52 A fraction (boiling point is 150 to 350 ° C.) and a wax fraction (boiling point is 350 ° C. or higher) are separated by line 51. Although it is fractionated into 3 fractions in the figure, it may be 2 fractions or 3 fractions or more. Further, it can be used for the next purification step without being particularly distilled.

As hydrotreating, the naphtha fraction (boiling point is less than 150 ° C.) is hydrorefined from the line 53 by the hydrorefining device 64, and the middle distillate (boiling point is 150 to 350 ° C.) is hydroisomerized from the line 52. The hydroisomerization reaction is performed in the apparatus 62, and the wax fraction (boiling point is 350 ° C. or higher) is hydrocracked in the hydrocracking apparatus 60 from the line 51.
As described above, after the hydrogen in the gas-liquid contact tower 30 is introduced from the line 32 and supplied to the gas-liquid contact tower 30 and consumed, excess hydrogen is discharged from the line 33. Excess hydrogen discharged from the line 33 is used for hydrorefining of the hydrorefining apparatus 64, hydroisomerization of the hydroisomerization apparatus 62, and hydrocracking of the hydrocracking apparatus 60. Can be used for hydrogen for hydrogenation process.

  In the hydrocracking device 60, the wax fraction distilled from the bottom of the first rectifying column 50 is hydrocracked. As the hydrocracking apparatus 60, a known fixed bed reaction tower can be used. In the present embodiment, in a reaction tower, a predetermined hydrocracking catalyst is charged into a fixed bed flow reactor and the wax fraction is hydrocracked.

The middle distillate hydrorefining (hydroisomerization) apparatus 62 is a liquid hydrocarbon (generally C ₁₁ to C ₁₁₎ having a middle boiling range supplied from the center of the first fractionator 50. ₂₀ ) is hydrorefined (hydroisomerized) with hydrogen. This hydrorefining reaction is a reaction such as isomerization of the liquid hydrocarbon or saturation by adding hydrogen to the unsaturated bond. As a result, the hydrorefined hydrocarbon-containing product is transferred to the second rectification column 70.

Naphtha fraction hydrotreating apparatus 64, a naphtha fraction distilled from the top of the first fractionator 50 (approximately _of C ₁₀ or less), purified hydrogenated with hydrogen gas. As a result, the hydrorefined hydrocarbon-containing product is transferred to the naphtha stabilizer 72, and a purified naphtha fraction is obtained from the lower part thereof. From the top of the naphtha stabilizer 72, gas mainly composed of C ₄ or less hydrocarbons are discharged.

  Next, the second rectifying column 70 joins the hydrocarbons treated in the wax fraction hydrocracking device 60 and the middle distillate hydroisomerization device 62 as described above to perform rectification, and a kerosene fraction. (The boiling point is about 150 to 250 ° C.) and the gas oil fraction (the boiling point is about 250 to 350 ° C.) is taken out. The mixing system of the hydrocarbons treated in the wax fraction hydrocracking reaction apparatus 60 and the middle fraction hydrotreating reaction apparatus 62 is not particularly limited, and may be tank blend or line blend. Then, the light component extracted from the top of the second rectifying column 70 is introduced into the line 76 of the stabilizer 72.

    The bottom fraction distilled from the bottom of the second rectifying column 70 is appropriately recycled to the wax hydrocracking device 60 via the line 75 and hydrocracked again to improve the cracking yield. be able to.

  As described above, a naphtha fraction, a kerosene fraction and a gas oil fraction can be produced from the FT synthetic crude oil, and the catalyst particles in the FT slurry are efficiently separated.

INDUSTRIAL APPLICABILITY The present invention can be used in a method for efficiently separating magnetic fine particles contained in FT synthetic crude oil obtained by FT synthesis using carbon monoxide and hydrogen as raw materials, in a reduced state using a magnetic separator.
Hereinafter, the present invention will be described in detail by way of examples.

<Preparation of catalyst>
(Catalyst A)
Silica alumina (silica / alumina molar ratio: 14) and an alumina binder were mixed and kneaded at a weight ratio of 60:40, and this was molded into a cylindrical shape having a diameter of about 1.6 mm and a length of about 4 mm. The carrier was obtained by baking for a period of time. This carrier was impregnated with an aqueous chloroplatinic acid solution to carry platinum. This was dried at 120 ° C. for 3 hours and then calcined at 500 ° C. for 1 hour to obtain Catalyst A. The supported amount of platinum was 0.8% by mass with respect to the carrier.

(Catalyst B)
USY zeolite having an average particle diameter of 1.1 μm (silica / alumina molar ratio: 37), silica alumina (silica / alumina molar ratio: 14) and alumina binder were mixed and kneaded at a weight ratio of 3:57:40. After forming into a cylindrical shape having a diameter of about 1.6 mm and a length of about 4 mm, the carrier was obtained by firing at 500 ° C. for 1 hour. This carrier was impregnated with an aqueous chloroplatinic acid solution to carry platinum. This was dried at 120 ° C. for 3 hours and then calcined at 500 ° C. for 1 hour to obtain Catalyst B. The supported amount of platinum was 0.8% by mass with respect to the carrier.

Example 1
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, led to the gas-liquid contact tower 30 filled with ceramic balls (particle diameter 3 mm), and the liquid containing the FT catalyst particles is taken up. Hydrogen and a treatment temperature of 350 ° C., LHSV 1.0 h ⁻¹ were brought into gas-liquid contact in parallel flow, and the FT catalyst particles in the liquid were treated with hydrogen to be reduced.
In addition, the hydrogen surplus by the reduction | restoration by hydrogen treatment was reused as a part of hydrogen used by a subsequent hydrogenation process (hydrogenation apparatus 60, 62, 64).

After that, the hydrogen-treated liquid is led from the line 31 to a high gradient magnetic separator (electromagnet-type high gradient magnetic separator (FEROSEP (registered trademark)) 40, and FT catalyst particles, liquid components and In this embodiment, the liquid-solid separator 20 as a pretreatment is not used, and the separated FT catalyst particles are separated from the magnetic separator 40 to the FT synthesis reactor 10 by a line 42 indicated by a dotted line. Returned to.
At this time, the average particle diameter of the FT catalyst at the inlet of the magnetic separator was 72.5 μm, and the removal rate of the separated FT catalyst particles (magnetic particle removal rate (% by mass)) was 94% by mass.

Here, the average particle size of the FT synthesis catalyst is analyzed by a laser diffraction particle size distribution measuring device (SALD-3100) manufactured by Shimadzu Corporation, and the particle removal rate is determined from the measurement result by measuring the magnetic particle concentration at the magnetic separator inlet. Means the value calculated by the following formula (hereinafter the same).
Particle removal rate (mass%) = 100 × (magnetic separator inlet magnetic particle concentration−magnetic separator outlet magnetic particle concentration) / magnetic separator inlet magnetic particle concentration

  The catalyst separated by the high gradient magnetic separator 40 is returned to the FT synthesis reactor 10, and the remaining liquid is led to the rectification column 50 for fractionation, and a naphtha fraction (boiling point is less than 150 ° C.) in the line 53. ), A middle distillate (boiling point 150 to 350 ° C.) in line 52 and a wax fraction (boiling point 350 ° C. or higher) in line 51.

(Hydroisomerization conditions for middle distillate)
Catalyst A (150 ml) was charged into a hydroisomerization apparatus 62 which is a fixed bed flow reactor, and the middle fraction obtained above was fed from the top of the hydroisomerization apparatus 62 at a rate of 300 ml / h. The hydrogenation treatment was performed under the following reaction conditions under a hydrogen stream.
That is, hydrogen is supplied from the top of the hydroisomerization unit 62 at a hydrogen / oil ratio of 338 NL / L to the middle distillate, and the back pressure valve is adjusted so that the reaction tower pressure is constant at an inlet pressure of 3.0 MPa. Then, the hydroisomerization reaction was performed under these conditions. The reaction temperature was 308 ° C. LHSV is 1.5h- ¹ .

(Hydrocracking conditions for wax fraction)
In a reaction tower 60 which is a hydrocracking apparatus, catalyst B (150 ml) is charged into a fixed bed flow reactor 60 as a hydrocracking apparatus, and the wax fraction obtained above is added to the top of the reaction tower 60. Then, hydrocracking was performed at a rate of 300 ml / h under a hydrogen stream under the following reaction conditions.

That is, hydrogen is supplied from the top of the reaction column 60, which is a hydrocracking apparatus, at a hydrogen / oil ratio of 676 NL / L with respect to the wax fraction, and the reaction column pressure is kept constant at an inlet pressure of 4.0 MPa. The pressure valve was adjusted and hydrocracked under these conditions. The reaction temperature at this time was 329 degreeC. LHSV is 2.5h- ¹ .

(Fractionation of hydroisomerization products and hydrocracking products)
The middle distillate hydroisomerization product (isomerization middle distillate) and the wax fraction hydrocracking product (wax cracking fraction) obtained above are line blended, and this mixture is mixed with the second fraction. Fractionated in the rectification column 70, the diesel fuel base material was extracted and stored in a tank (not shown).

The bottom of the second rectifying column 70 was continuously returned to the inlet of the hydrocracking reaction apparatus 60 via the line 75, and hydrocracked again.
Further, the top component of the second rectifying column 70 was extracted from the top of the column, introduced into the extraction line 76 from the hydrotreating reactor 64, and led to the stabilizer 72.

(Comparative Example 1)
The same treatment as in Example 1 was carried out except that no gas-liquid contact tower was installed in the subsequent stage of the FT synthesis reactor (hydrogen treatment was not carried out). That is, magnetic separation was performed without hydrogen treatment. At this time, the removal rate (magnetic particle removal rate (mass%)) of the separated FT catalyst particles was 87 mass%.

(result)
It can be seen that Example 1 in which the slurry was subjected to hydrogen treatment at 350 ° C. was excellent in the removal rate of FT catalyst particles (magnetic particles) in the liquid and had better magnetic separation efficiency than Comparative Example 1 in which the hydrogen treatment was not performed. .

(Example 2)
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 synthesis 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 in the FT synthesis reactor 10 is taken out from the line 3 as a slurry containing FT synthesis catalyst particles, and the taken slurry is placed in the subsequent stage of the FT synthesis reactor (sintered metal filter). : Opening 20 μm) After that, it is led to a gas-liquid contact tower 30 filled with ceramic balls (particle size 3 mm) in line 1, and the liquid containing FT synthesis catalyst particles is treated with hydrogen and a treatment temperature of 300 ° C., LHSV 1 The FT synthesis catalyst particles in the liquid were subjected to hydrogen treatment and reduced by co-current gas-liquid contact under the condition of 0.0 h- ¹ .
The surplus hydrogen in the hydrogen treatment was reused as part of the hydrogen used in the subsequent hydrogenation step (hydrogenation reaction devices 60, 62, 64).

Thereafter, in line 31, the hydrogen-treated liquid is led to a high gradient magnetic separator (electromagnet type high gradient magnetic separator (FEROSEP (registered trademark))) 40, and FT synthesis catalyst particles and liquid components are treated under the treatment conditions shown in Table 1. To separate. The FT catalyst particles separated by the liquid-solid separation step and the high gradient magnetic separator were returned to the FT synthesis reactor.
At this time, the average particle diameter of the FT catalyst at the inlet of the magnetic separator was 10 μm, and the removal rate of the separated FT synthesis catalyst particles (magnetic particle removal rate (mass%)) was 52 mass%.

  The catalyst separated by the high gradient magnetic separator 40 is returned to the FT synthesis reactor 10 by a line 42 indicated by a dotted line, and the liquid component is guided to the first rectification column 50 for fractionation. Fraction (boiling point is less than 150 ° C.), the middle fraction (boiling point is 150 to 350 ° C.) in line 52 and the wax fraction (boiling point is 350 ° C. or more) in line 51. Each fraction was treated in the same manner as in Example 1, and the diesel fuel base material was extracted and stored in a tank (not shown).

(Example 3)
The same treatment as in Example 2 was performed except that the hydrogen treatment temperature in the gas-liquid contact tower was changed to 350 ° C. At this time, the removal rate (magnetic particle removal rate (% by mass)) of the separated FT synthesis catalyst particles was 56% by mass.

(Comparative Example 2)
The same treatment as in Example 2 was performed, except that no gas-liquid contact tower was installed in the subsequent stage of the FT synthesis reactor (hydrogen treatment was not performed). At this time, the removal rate (magnetic particle removal rate (% by mass)) of the separated FT synthesis catalyst particles was 43% by mass.

(Comparative Examples 3-4)
The same treatment as in Example 2 was performed except that the hydrogen treatment temperature in the gas-liquid contact tower was changed to 200 ° C. and 250 ° C., respectively. At this time, the removal rate (magnetic particle removal rate (% by mass)) of the separated FT synthesis catalyst particles was 44% by mass in Comparative Example 3 and 46% by mass in Comparative Example 4.

(result)
Examples 2 and 3 in which hydrogen treatment was performed at treatment temperatures of 300 ° C. and 350 ° C., compared with Comparative Examples 2 to 4 in which hydrogen treatment was not performed or hydrogen treatment was performed at a low temperature (FT catalyst particles ( It can be seen that the removal rate of magnetic particles is excellent and the magnetic separation efficiency is good.

Fuel comprising FT synthesis reactor 10, liquid-solid separator 20 for separating fine particles in FT synthetic crude oil, gas-liquid contact tower 30 for hydrogen treatment, and high gradient magnetic separator 40 for magnetically separating magnetic fine particles Production plant. It is a model schematic diagram of the high gradient magnetic separator 40 used for this invention.

Explanation of symbols

10 FT synthesis reactor 20 liquid-solid separator 30 hydrogen reduction tower 40 magnetic separator 60 first rectifying tower 70 for fractionating FT synthetic crude oil second rectifying tower

Claims (4)

A method for producing a Fischer-Tropsch synthetic crude oil comprising the following steps (1) and (2):
(1) hydrotreating the residual Fischer-Tropsch catalyst by bringing the slurry containing the residual Fischer-Tropsch catalyst extracted from the Fischer-Tropsch synthesis reactor into contact with hydrogen at 270 ° C. or higher, and (2 Next, a magnetic separation step of capturing and removing the hydrotreated Fischer-Tropsch catalyst from the slurry by a high gradient magnetic separator.   A group consisting of a filter, a gravity sedimentation separator, a cyclone, and a centrifuge at any one of the stage before the hydrotreating process, the stage between the hydrotreating process and the magnetic separation process, and the stage after the high gradient magnetic separator. The method for producing a synthetic crude oil according to claim 1, further comprising a liquid-solid separation step selected from:   The method for producing a synthetic crude oil according to claim 1 or 2, wherein the Fischer-Tropsch synthesis catalyst removed by the high gradient magnetic separator is returned to the Fischer-Tropsch synthesis reactor.   The method further comprises a step of hydrogenating the obtained synthetic crude oil, wherein surplus hydrogen used in the hydroprocessing step is reused as part of hydrogen in the hydrogenation step. The manufacturing method of the synthetic crude oil in any one.

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