JP5990389B2 - Hydrocarbon oil production method, bubble column type slurry bed reactor, and hydrocarbon oil production system - Google Patents

Description

  The present invention relates to a hydrocarbon oil production method, a bubble column type slurry bed reactor, and a hydrocarbon oil production system.

  In recent years, liquid fuels having a low content of environmentally hazardous substances such as sulfur and aromatic hydrocarbons have been demanded due to an increase in environmental awareness. From this point of view, natural gas is reformed as a technology that can produce fuel oil bases that are substantially free of sulfur and aromatic hydrocarbons and rich in aliphatic hydrocarbons, especially kerosene / light oil bases. A method of producing a synthesis gas containing carbon monoxide gas and hydrogen gas and utilizing a Fischer-Tropsch synthesis reaction (hereinafter sometimes referred to as “FT synthesis reaction”) using this synthesis gas as a raw material has been studied. (For example, refer to Patent Document 1). This technique is called a GTL (Gas To Liquids) process.

  The hydrocarbon oil obtained by the FT synthesis reaction is a mixture containing a normal paraffin having a wide carbon number distribution as a main component and an olefin and an oxygen-containing compound. By subjecting this hydrocarbon oil to a process called upgrading, which is refined by hydrotreating and fractionation, a naphtha fraction containing a large amount of components having a boiling point lower than about 150 ° C., and a boiling point of about 150 to about 360 ° C. A middle distillate containing a large amount of these components can be obtained. Among these fractions, the middle fraction is the most useful fraction corresponding to the kerosene / light oil base material, and it is desired to obtain this in a high yield.

  As one of the reaction apparatuses for producing hydrocarbon oil by FT synthesis reaction, a catalyst having activity in FT synthesis reaction comprising solid particles in hydrocarbon oil (hereinafter sometimes referred to as “FT synthesis catalyst”). A bubble column type slurry bed reaction apparatus is known in which synthesis gas is blown into a suspended slurry to perform a reaction (see, for example, Patent Document 2). This bubble column type slurry bed reactor has a slurry part in the lower part of the reactor and a gas phase part in the upper part, and is separated from the catalyst particles from the slurry part as a product of the FT synthesis reaction by a filter. Liquid hydrocarbons are extracted, and gaseous hydrocarbons are extracted from the gas phase portion under the conditions in the reactor.

  The liquid hydrocarbon extracted from the slurry portion is a relatively heavy hydrocarbon (hereinafter sometimes referred to as “heavy hydrocarbon oil”) containing a large amount of a wax fraction having approximately 22 or more carbon atoms. . On the other hand, gaseous hydrocarbons extracted from the gas phase portion contain a large fraction of carbon atoms of approximately 21 or less, and are cooled outside the reactor. Among them, hydrocarbons having 5 or more carbon atoms are mainly condensed and liquid carbonized. Hydrogen (hereinafter sometimes referred to as “light hydrocarbon oil”) is obtained. Each of the heavy hydrocarbon oil and the light hydrocarbon oil is subjected to an upgrade process.

  In general, the activity of the FT synthesis catalyst gradually decreases with the passage of operating time. Therefore, in order to maintain the productivity of hydrocarbon oil, an operation is generally performed in which the reaction temperature is increased with time so as to meet the decrease in the activity of the FT synthesis catalyst and the conversion of carbon monoxide is kept constant. .

JP 2004-323626 A US Patent Application Publication No. 2007/0014703

  By the way, in the FT synthesis reaction, the chain growth probability (α) decreases with an increase in the reaction temperature, and the number of carbon atoms of the generated hydrocarbon decreases. In addition, when the reaction temperature, that is, the temperature of the slurry part, increases in the bubble column type slurry bed reactor, the vapor pressure of hydrocarbons constituting the slurry increases, and the amount of hydrocarbons that vaporize and move to the gas phase part increases. At the same time, the temperature of the gas phase rises. As a result, the amount of gaseous hydrocarbons discharged from the gas phase portion increases, and the amount of heavy hydrocarbon oil extracted from the slurry portion tends to decrease. Further, a part of the wax fraction in the slurry is vaporized and tends to be easily discharged from the gas phase portion. Thus, in the production of hydrocarbon oil by FT synthesis reaction using a bubble column type slurry bed reactor, the amount of gaseous hydrocarbons discharged from the gas phase and the composition thereof are the reaction temperature (slurry temperature). Susceptible to.

  When the amount of gaseous hydrocarbons extracted from the gas phase increases due to an increase in the reaction temperature (slurry temperature), it is necessary to enhance the capacity of the cooler to cool this to obtain light hydrocarbon oil. is there. In addition, the amount of light hydrocarbon oil produced by cooling gaseous hydrocarbons and the composition of the light hydrocarbon oil change over time, and the light hydrocarbon oil is hydrorefined and hydroisomerized during the subsequent upgrade process. This causes a problem that the operation of the hydrorefining process to become unstable becomes unstable. Furthermore, when the content of the wax fraction in the gaseous hydrocarbons extracted from the gas phase part increases, the flow rate in the cooler for cooling the gaseous hydrocarbons to obtain light hydrocarbon oil becomes solid. Some wax adheres, heat transfer efficiency falls, and the problem that the flow path may be blocked in some cases may occur.

  Therefore, the present invention is a method for producing a hydrocarbon oil that obtains a hydrocarbon oil by an FT synthesis reaction using a bubble column type slurry bed reactor, and is extracted from the gas phase portion even when the reaction temperature changes. Method for producing hydrocarbon oil capable of suppressing change in amount and composition of gaseous hydrocarbon, bubble column type slurry bed reactor capable of carrying out the production method, and bubble column type slurry bed reactor It aims at providing the manufacturing system of hydrocarbon oil provided with.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, have obtained the following knowledge and have completed the present invention.

  That is, the present inventors have provided a cooling means in the gas phase portion in the reactor of the bubble column type slurry bed reactor to cool the gas phase portion, thereby increasing the reaction temperature (temperature of the slurry portion). In addition, the inventors have found that the amount of gaseous hydrocarbons discharged from the gas phase portion and changes in the composition thereof can be suppressed.

  The present invention relates to a method for producing a hydrocarbon oil by using a bubble column type slurry bed reactor to obtain a hydrocarbon oil by a Fischer-Tropsch synthesis reaction, the catalyst provided in the bubble column type slurry bed reactor In a reactor having a slurry part containing particles and liquid hydrocarbons and a gas phase part located above the slurry part, the gas phase part is cooled, and the gaseous hydrocarbons in the gas phase part are cooled. Provided is a method for producing a hydrocarbon oil, characterized in that a part is condensed and returned to the slurry portion.

  According to the method for producing a hydrocarbon oil of the present invention, even if the reaction temperature changes during the operation of the FT synthesis reaction using the bubble column type slurry bed reactor, the reactor constituting the bubble column type slurry bed reactor Changes in the amount and composition of gaseous hydrocarbons discharged from the gas phase can be suppressed.

  In the method for producing hydrocarbon oil of the present invention, the gas phase part can be cooled by a cooling pipe in which a cooling medium is circulated. According to such a cooling method, the gas phase portion can be efficiently cooled with simple equipment.

  Moreover, in the method for producing hydrocarbon oil of the present invention, it is preferable to increase the amount of heat removed by cooling the gas phase portion as the temperature of the slurry portion of the bubble column type slurry bed reactor increases.

  By increasing the temperature of the slurry part in the reactor during the operation of the bubble column type slurry bed reactor and increasing the amount of heat removed by cooling the gas phase part, the decrease in the activity of the FT synthesis catalyst is compensated. The amount of gaseous hydrocarbons discharged from the gas phase portion of the reactor and the content of wax fraction in the gaseous hydrocarbons by maintaining the conversion of carbon monoxide constant and increasing the temperature of the slurry portion. The increase can be further suppressed.

  The present invention also provides a bubble column comprising: a reactor in which a slurry part containing catalyst particles and a gas phase part located above the slurry part are formed; and a cooling means for cooling the gas phase part. A type slurry bed reactor is provided.

  By using the bubble column type slurry bed reactor of the present invention, the hydrocarbon oil production method of the present invention can be efficiently carried out.

  In the bubble column type slurry bed reactor of the present invention, the cooling means may be a cooling pipe in which a cooling medium is circulated. According to such a bubble column type slurry bed reactor, the gas phase can be efficiently cooled with simple equipment.

  The present invention also provides a hydrocarbon oil production system comprising the bubble column type slurry bed reactor of the present invention. According to such a hydrocarbon oil production system, it is possible to efficiently and stably produce a hydrocarbon oil that is substantially free of environmentally hazardous substances and is an excellent liquid fuel base material.

  According to the present invention, a hydrocarbon oil production method for obtaining a hydrocarbon oil by an FT synthesis reaction using a bubble column type slurry bed reactor, which is extracted from the gas phase portion even when the reaction temperature changes. Of hydrocarbon oil capable of suppressing change in amount and composition of gaseous hydrocarbon produced, bubble column type slurry bed reactor capable of carrying out the production method, and bubble column type slurry bed reaction A hydrocarbon oil production system comprising the apparatus is provided.

It is a mimetic diagram of a manufacturing system of hydrocarbon oil concerning one embodiment of the present invention.

  In the present invention, the hydrocarbon oil is a liquid hydrocarbon mixture mainly composed of normal paraffin and containing an olefin and an oxygen-containing compound synthesized from carbon monoxide and hydrogen by an FT synthesis reaction, or the liquid hydrocarbon mixture or It means liquid hydrocarbons obtained by subjecting the fraction obtained by fractional distillation to hydrorefining including hydroisomerization or hydrocracking including hydroisomerization, and further fractionating as necessary. .

  Hereinafter, a hydrocarbon oil production system and a hydrocarbon oil production method using the production system according to an embodiment of the present invention will be described in detail with reference to the drawings.

(Hydrocarbon oil production system)
The hydrocarbon oil production system 100 used in the present embodiment shown in FIG. 1 is a GTL process for converting a hydrocarbon raw material such as natural gas into a liquid fuel base material (hydrocarbon oil) such as light oil, kerosene and naphtha. It is an example of the plant equipment for implementing. The hydrocarbon oil production system 100 of this embodiment reforms a hydrocarbon such as natural gas to produce a synthesis gas (not shown), and produces a hydrocarbon oil from the synthesis gas by an FT synthesis reaction. The bubble column type slurry bed reaction apparatus 10, the heavy hydrocarbon oil hydrocracking apparatus C4, the light hydrocarbon oil hydrotreating apparatus C6, and the rectifying apparatus C8 are mainly provided, and other apparatuses are provided as necessary. These devices are connected by a transfer line or the like. The “line” means a pipe for transferring a fluid.

  For example, as shown in FIG. 1, the bubble column type slurry bed reactor 10 contains a slurry portion S made of a slurry containing liquid hydrocarbons and FT synthesis catalyst particles suspended in the liquid hydrocarbons in the lower part, A bubble column type slurry bed reactor (hereinafter sometimes simply referred to as “reactor”) C2 having a gas phase portion G at the upper portion of the portion S, and the slurry portion S in the reactor C2 are disposed in the FT. The first cooling means H2 for controlling the temperature of the slurry part S by removing the reaction heat of the synthesis reaction, and the gas phase part disposed in the gas phase part G in the reactor C2 are cooled to reduce the temperature. The second cooling means H4 for controlling, the synthesis gas supply line L2 for blowing the synthesis gas into the bottom of the reactor C2, and the hydrocarbon oil (heavy) under the conditions in the reactor C2 generated by the FT synthesis reaction Hydrocarbon oil) and FT synthesis catalyst particles An extraction line L4 for extracting the slurry, and a catalyst separation tank D2 with a built-in filter F for separating heavy hydrocarbon oil and FT synthesis catalyst particles in the slurry extracted by the extraction line L4; The heavy hydrocarbon oil discharge line L6 that discharges the heavy hydrocarbon oil separated in the catalyst separation tank D2 reacts with the FT synthesis catalyst particles separated in the catalyst separation tank D2 and some heavy hydrocarbon oil. A return pipe L8 for returning to the reactor C2, a discharge line L10 for discharging hydrocarbons, water vapor and unreacted synthesis gas which are gaseous under the conditions in the reactor C2 generated by the FT synthesis reaction; Light component cooling means H6 for cooling gaseous hydrocarbons, water vapor and unreacted synthesis gas extracted by line L10, and condensation by light component cooling means H6 Gas-liquid / oil-water separation of liquid hydrocarbons (light hydrocarbon oils) mainly composed of hydrocarbons having 5 or more carbon atoms, water, and gas components composed of unreacted synthesis gas and mainly hydrocarbon gases having 4 or less carbon atoms Recycle for connecting the gas / liquid / oil / water separation tank D4, the gas / liquid / oil / water separation tank D4, and the synthesis gas supply line L2 to recycle the gas separated in the gas / liquid / oil / water separation tank D4 to the reactor C2. It is mainly composed of a line L12 and a light hydrocarbon oil discharge line L14 for discharging light hydrocarbon oil from the gas-liquid / oil-water separator D4.

  The first cooling means H2 is desirably a cooling pipe through which a cooling medium, preferably water, is circulated. The shape of the cooling pipe can efficiently remove reaction heat generated by the FT synthesis reaction in the slurry portion S in the reactor C2, and the filter F is connected to the slurry portion S in the reactor C2. In the case of being arranged, there is no particular limitation as long as a space for arranging the filter F can be secured. When the cooling medium flowing through the cooling pipe is water, reaction heat generated by the FT synthesis reaction is removed as sensible heat (temperature increase) and / or latent heat (vaporization heat) of water. The water vapor generated by the vaporization of water can be used as a reaction raw material, a heat medium for heating, a driving turbine of a generator, or the like, inside or outside the GTL process, and the heat energy of the water vapor is used. The condensed water generated later can be reused as the cooling medium.

  The second cooling means H4 is also desirably a cooling pipe through which a cooling medium, preferably water, flows. The shape of the cooling pipe can efficiently cool hydrocarbons that volatilize and rise from the slurry part S, water vapor generated as a by-product by the FT synthesis reaction, and unreacted synthesis gas in the gas phase part G in the reactor C2. If it is a thing, it will not specifically limit.

  The second cooling means H4 acts to control the temperature of the mixture of gaseous hydrocarbons, water vapor and unreacted synthesis gas to a predetermined value at the top of the reactor C2 to which the line L10 is connected. Is preferred.

  The second cooling means H2 may directly supply a gas having a temperature lower than the temperature of the gas phase part G in the reactor C2 to the gas phase part G as a “quenching gas”. As the “quenching gas”, for example, a hydrocarbon gas having 4 or less carbon atoms produced by the reaction in the FT synthesis reaction or the upgrade process can be used.

  In addition, the bubble column type slurry bed reactor 10 is a flow direction of the slurry for separating the slurry into heavy hydrocarbon oil and FT synthesis catalyst particles with respect to the filter F disposed in the catalyst separation tank D2. In the opposite direction, the heavy hydrocarbon oil from which the FT synthesis catalyst particles have been removed is intermittently circulated, and an operation (back washing) for removing the FT synthesis catalyst particles deposited on the filtration surface of the filter F is performed. It is preferable to have equipment (not shown) for this purpose. The FT synthesis catalyst particles removed by backwashing and the heavy hydrocarbon oil used for backwashing are returned to the slurry part S in the reactor C2 through the return pipe L8.

  In the above example, the filter F is built in the catalyst separation tank D2 disposed outside the reactor C2. However, the filter F is used as the slurry of the reactor C2 without providing the catalyst separation tank D2. You may arrange | position in the part S. In this case, the FT synthesis catalyst particles desorbed from the filter F by backwashing the filter F and the heavy hydrocarbon oil used for backwashing directly flow into the slurry portion S in the reactor C2. Further, the filter F may be disposed both in the external catalyst separation tank D2 and in the reactor C2.

  Moreover, in said example, although the light part cooling means H6 and the gas-liquid oil-water separation tank D4 have each single structure, the combination of a some cooling means and separation tank may be sufficient.

  The heavy hydrocarbon oil discharge line L6 is connected to the heavy hydrocarbon oil hydrocracker C4 via a fractionator (not shown) as necessary. The heavy hydrocarbon oil hydrocracking unit C4 is mainly composed of a fixed bed reactor packed with a catalyst having activity for hydrocracking and hydroisomerization, and a heavy hydrocarbon oil upstream of the reactor. The heating means (not shown) for heating the mixture of hydrogen and hydrogen gas, the cooling means for cooling the reaction product downstream, and the unreacted hydrogen gas and the gaseous hydrocarbon produced by the reaction are separated and separated. A gas-liquid separation tank (not shown) for removal is preferably provided in multiple stages.

  The light hydrocarbon oil discharge line L14 is connected to a light hydrocarbon oil hydrorefining device C6 via a fractionation device (not shown) as necessary. The light hydrocarbon oil hydrorefining apparatus C6 is mainly composed of a fixed bed reactor packed with a catalyst having activity for hydrorefining and hydroisomerization, and light hydrocarbon oil and hydrogen are upstream of the reactor. Heating means (not shown) for heating the mixture with the gas, cooling means for cooling the reaction product downstream, and unreacted hydrogen gas and gaseous hydrocarbons produced by the reaction are separated and removed. Gas-liquid separation tank (not shown).

  The heavy hydrocarbon oil hydrocracking unit C4 and the light hydrocarbon oil hydrotreating unit C6 are supplied with liquid hydrocarbons obtained by hydrocracking heavy hydrocarbon oil and hydrotreating light hydrocarbon oil, respectively. Transfer lines L16 and L18 for transfer are connected, and transfer lines L16 and L18 merge with transfer line L20. The rectifying apparatus C8 connected to the transfer line L20 is mainly composed of a rectifying column for fractionating a mixture of liquid hydrocarbons obtained by hydrocracking heavy hydrocarbon oil and hydrorefining light hydrocarbon oil. And heating means (not shown) for heating the mixture upstream thereof. The rectifying column is connected to extraction lines L22, L24, and L26 for extracting the fractionated fractions, for example, naphtha fraction, kerosene fraction, and light oil fraction, respectively. The lines are connected to storage tanks T2, T4, T6 for storing the respective fractions. A stabilizer (not shown), which is a distillation facility for removing gaseous hydrocarbons having 4 or less carbon atoms dissolved in the distillate, is further provided in the line for extracting the naphtha distillate from the rectifying apparatus C8. The naphtha fraction that is connected and passes through this stabilizer is stored.

  Also, from the bottom of the rectifying column constituting the rectifying apparatus C8, so-called “undecomposed wax” that has not been decomposed until the carbon number is about 21 or less in the heavy hydrocarbon oil hydrocracking apparatus C4, An undecomposed wax recycling line L28 for recycling is provided upstream of the heavy hydrocarbon oil hydrocracker C4.

  The heavy hydrocarbon oil hydrocracking unit C4, light hydrocarbon oil hydrotreating unit C6, rectifying unit C8 and the equipment attached thereto are so-called upgrades that purify the hydrocarbon oil obtained by the FT synthesis reaction. It is equipment for carrying out the grading process.

(Method for producing hydrocarbon oil)
A method for producing hydrocarbon oil using the production system 100 will be described below.

<Reforming process>
In a reformer (not shown), natural gas or the like, which is a hydrocarbon raw material, is subjected to a reforming reaction together with water vapor and / or carbon dioxide by a known method to produce a synthesis gas containing carbon monoxide and hydrogen gas. To manufacture. You may adjust the ratio of carbon monoxide and hydrogen gas so that the obtained synthesis gas may be suitable as a raw material of FT synthesis reaction as needed.

<FT synthesis reaction process>
In the bubble column type slurry bed reactor 10, the hydrocarbon oil according to this embodiment is produced by the FT synthesis reaction using the synthesis gas as a raw material. In the bubble column type slurry bed reactor 10, a heavy hydrocarbon oil mainly composed of a wax fraction having a carbon number of approximately 22 or more and a light hydrocarbon mainly comprising a fraction having a carbon number of approximately 21 or less. A hydrocarbon oil is obtained.

The slurry portion S in the lower part of the reactor C2 contains a slurry in which FT synthesis catalyst particles are suspended in liquid hydrocarbon (product of FT synthesis reaction). The synthesis gas (CO and H ₂ ) obtained in the reforming process is blown into the slurry part S in the reactor C2 through a dispersion plate (not shown) installed at the bottom of the reactor C2 by the synthesis gas supply line L2. . The synthesis gas blown into the slurry part S becomes bubbles and rises in the slurry part S toward the upper part of the reactor C2. In the process, the synthesis gas dissolves in the liquid hydrocarbon and comes into contact with the FT synthesis catalyst particles, whereby the FT synthesis reaction proceeds to produce hydrocarbon and water. The FT synthesis reaction is represented, for example, by the following chemical reaction formula (1).
(2n + 1) H ₂ + nCO → H (CH ₂ ) _n H + nH ₂ O (1)
In addition, in the FT synthesis reaction, in addition to the reaction for generating normal paraffin and water represented by the chemical reaction formula (1), the reaction for generating an olefin and the alcohol containing an oxygen atom derived from carbon monoxide. Reactions that produce oxygen-containing compounds such as these also occur as side reactions. Therefore, the hydrocarbon obtained by the FT synthesis reaction contains normal paraffin as a main component and olefin and oxygen-containing compound as impurities. Further, n in the chemical reaction formula (1) covers a wide range of about 1 to 100, for example.

  Of the hydrocarbons (including oxygen-containing compounds) generated in the slurry part S, relatively heavy hydrocarbons have a low vapor pressure under the temperature conditions in the reactor C2, and remain in the slurry part S as liquid. A part of the slurry composed of the liquid hydrocarbon (heavy hydrocarbon oil) and the FT synthesis catalyst particles is extracted to the catalyst separation tank D2 via the extraction line L4, and is disposed in the catalyst separation tank D2. The filter F is separated into heavy hydrocarbon oil and FT synthesis catalyst particles. The separated heavy hydrocarbon oil is transferred to the upgrading process through the heavy hydrocarbon oil discharge line L6. As described above, the separation between the heavy hydrocarbon oil and the FT synthesis catalyst particles may be performed in the reactor C2 by the filter F disposed in the slurry portion S of the reactor C2. Alternatively, it may be performed both in the catalyst separation tank D2 and in the reactor C2.

  The synthesis gas supplied to the reactor C2 usually does not all react in the slurry portion and is converted into hydrocarbons, but a part of the synthesis gas passes through the slurry portion without being reacted. The conversion rate of carbon monoxide when the synthesis gas passes through the reactor C2 once is preferably about 50 to 90%. Unreacted synthesis gas moves from the slurry portion S to the gas phase portion G above it, and is further discharged from a discharge pipe L10 connected to the top of the reactor C2. Further, water (steam), which is one of the reaction products, passes through the gas phase portion together with the unreacted synthesis gas and is discharged through the discharge pipe L10. Further, among the hydrocarbons generated in the slurry part S, relatively light hydrocarbons (for example, mainly having 21 or less carbon atoms) having a high vapor pressure under the temperature conditions in the reactor C2 are vaporized in the slurry part and are not reacted. It moves to the gaseous-phase part G with the synthesis gas and water vapor | steam, and the gaseous hydrocarbon is discharged | emitted from the discharge line L10 in the reactor top part.

  The mixture composed of unreacted synthesis gas, water vapor and gaseous hydrocarbons discharged from the discharge line L10 is cooled to, for example, about 30 ° C. by the light component cooling means H6 (heat exchanger). By this cooling, mainly hydrocarbons having 5 or more carbon atoms and water vapor are condensed. On the other hand, the unreacted synthesis gas and the hydrocarbon gas mainly having 1 to 4 carbon atoms produced by the FT synthesis reaction remain in a gaseous state, and in the subsequent gas-liquid / oil-water separation tank D4, this gas component and liquid hydrocarbon (light (Hydrocarbon oil) and water are gas-liquid / oil-water separated to obtain light hydrocarbon oil. The obtained light hydrocarbon oil is transferred to the upgrading process through the light hydrocarbon oil discharge line L14. The gas component separated in the gas-liquid / oil-water separation tank D4 is recycled by the recycle line L12, and is supplied to the reactor C2 together with the newly supplied synthesis gas by the synthesis gas supply line L2. Is again subjected to the FT synthesis reaction.

  A known FT synthesis catalyst in which an active metal is supported on an inorganic carrier is used as the FT synthesis catalyst used in the reactor C2 constituting the bubble column type slurry bed reactor 10 and constituting the slurry. As the inorganic carrier, porous oxides such as silica, alumina, titania, magnesia, zirconia are used, silica or alumina is preferable, and silica is more preferable. Examples of the active metal include cobalt, ruthenium, iron, nickel and the like. Cobalt and / or ruthenium are preferable, and cobalt is more preferable. The active metal loading is preferably 3 to 50% by mass, more preferably 10 to 40% by mass, based on the mass of the carrier. When the amount of the active metal supported is less than 3% by mass, the activity tends to be insufficient, and when it exceeds 50% by mass, the activity tends to decrease due to aggregation of the active metal. In addition to the above active metals, the FT synthesis catalyst may carry other metal components for the purpose of improving the activity, or for the purpose of controlling the number and carbon distribution of the hydrocarbons produced. Examples of other components include compounds containing metal elements such as zirconium, titanium, hafnium, sodium, lithium, and magnesium. The average particle diameter of the FT synthesis catalyst particles is preferably 40 to 150 μm so that the catalyst particles can easily flow as a slurry suspended in liquid hydrocarbon in the slurry bed reactor. Similarly, from the viewpoint of fluidity as a slurry, the shape of the FT synthesis catalyst particles is preferably spherical.

  The manufacturing method of the said FT synthesis catalyst is not limited, It prepares by a well-known method. For example, a solution containing a compound containing an active metal element (for example, a metal salt) is used, and the compound containing the active metal element is supported on the carrier by an impregnation method typified by the Incipient Wetness method. The carrier on which the compound containing the active metal element is supported is dried and calcined by a known method, and is usually reduced by heating with a reducing gas such as hydrogen to impart high activity to the FT synthesis reaction. FT synthesis catalyst.

  The reaction conditions for the FT synthesis reaction in the reactor C2 are not limited. For example, the following reaction conditions are selected. That is, the reaction temperature (temperature of the slurry part S) is 150 to 300 ° C, preferably 180 to 270 ° C. When the reaction temperature is lower than 150 ° C., the FT synthesis reaction tends not to proceed sufficiently, and when the reaction temperature exceeds 300 ° C., the number of carbon atoms of the generated hydrocarbon tends to decrease, which is not preferable. . The reaction pressure is preferably 0.5 to 5.0 MPa. If the reaction pressure is less than 0.5 MPa, the FT synthesis reaction tends not to proceed efficiently. If the reaction pressure exceeds 5.0 MPa, the apparatus cost increases from the viewpoint of imparting pressure resistance. It is not preferable. The hydrogen / carbon monoxide ratio (molar ratio) in the raw material gas is preferably 0.5 to 4.0 from the viewpoint that the reaction proceeds efficiently.

  In addition, reaction temperature is the temperature of the slurry part S here, and is controlled by the 1st cooling means H2. The FT synthesis reaction is a reaction accompanied by a large exotherm, and usually the reaction temperature is controlled by removing the reaction heat by the first cooling means H2. In addition, when the temperature of the slurry part S is not uniform over the whole area of the slurry part S, the temperature of the slurry part S referred to in the present application is the upper surface (interface with the gas phase part G) of the slurry part S or its The temperature of the nearby slurry part S is said.

  In general, a new FT synthesis catalyst and liquid hydrocarbons (usually heavy hydrocarbon oil, which is a product of the FT synthesis reaction) are charged into the reactor C2, and synthesis gas is supplied to operate the FT synthesis reaction. When the operation is started (startup) and the operation is continued thereafter, the activity of the FT synthesis catalyst gradually decreases as the operation time elapses, and the conversion rate of carbon monoxide in the synthesis gas tends to decrease with time. Since it is necessary to maintain high productivity in the commercial operation, the reaction temperature (temperature of the slurry part S) is increased with time so as to compensate for the decrease in the activity of the FT synthesis catalyst, and carbon monoxide. In general, an operation for keeping the conversion rate of is constant.

  On the other hand, in the FT synthesis reaction, the chain growth probability (α) decreases with an increase in the reaction temperature, and the number of carbon atoms of the generated hydrocarbon decreases. Moreover, the vapor pressure of hydrocarbons in the reactor C2 increases as a whole due to the increase in the reaction temperature. When the reaction temperature is increased due to these two factors, the amount of gaseous hydrocarbons vaporized in the slurry portion S and moved to the gas phase portion G and discharged from the discharge line L10 increases. And the temperature of the gaseous-phase part G rises. Furthermore, when the temperature of the slurry portion S is low, the vapor pressure of hydrocarbons (wax fraction) having a carbon number of approximately 22 or more, which hardly vaporized, is increased, and this fraction moves to the gas phase portion G. Will increase.

  When the amount of gaseous hydrocarbons discharged from the discharge line L10 increases by increasing the reaction temperature, the light matter cooling means H6 cools the discharge from the discharge line L10 to a predetermined temperature (for example, about 30 ° C.). Thus, in order to reliably obtain light hydrocarbon oil, it is necessary to design the cooling capacity of the light component cooling means H6 so as to meet this, which causes a problem that the equipment cost increases. In addition, when the amount of light hydrocarbon oil produced and its composition change, it is part of the upgrading process, and light hydrocarbon oil hydrorefining equipment C6 for hydrorefining and hydroisomerizing light hydrocarbon oil. This causes a problem that the operation in the vehicle becomes unstable. Further, when the content of the wax fraction in the gaseous hydrocarbon discharged from the discharge line L10 increases, the wax fraction deposited by cooling adheres as a solid in the flow path of the light component cooling means H6. There may be a problem that the heat transfer efficiency is lowered or the flow path is blocked.

  Thus, as the operating time elapses, by increasing the reaction temperature (temperature of the slurry part S) in order to compensate for the decrease in the activity of the FT synthesis catalyst, the temperature of the gas phase part G also rises, and the discharge line Changes in the amount and composition of gaseous hydrocarbons discharged from L10 result in the aforementioned problems.

  In the method for producing hydrocarbon oil according to the present embodiment, in order to prevent or suppress the occurrence of the above problem, the second cooling means H4 provided in the gas phase part G in the reactor C2 causes the gas phase part. Cooling a gaseous substance in G, that is, a mixture of unreacted synthesis gas that moves up from the slurry part S to the gas phase part G, water vapor, and hydrocarbons that are gaseous under the conditions in the reactor C2, Adjust the temperature. Here, the temperature of the gas phase part G means the temperature of the mixture at the top of the reactor C2 (discharge line L10 connection part), that is, the outlet of the gas phase part G, and the second cooling means H4 is a means for adjusting this temperature. It is.

  By cooling the gas phase portion G by the second cooling means H4, the fraction having a relatively large carbon number among the gaseous hydrocarbons rising in the gas phase portion G is condensed and returned to the slurry portion S. Therefore, this cooling suppresses an increase in the amount of gaseous hydrocarbons discharged from the discharge line L10 and the content of the wax fraction in the gaseous hydrocarbons as the temperature of the slurry portion S increases. This prevents or suppresses the occurrence of the aforementioned problems.

  The second cooling means H4 is preferably a cooling pipe through which a cooling medium flows, and the gas phase portion G is preferably cooled by this cooling pipe. By using the cooling pipe, the gas phase portion G can be efficiently cooled by a simple facility with less energy loss.

  In the method for producing hydrocarbon oil according to the present embodiment, the temperature of the slurry portion S in the reactor C2 is increased during the operation of the bubble column type slurry bed reactor 10, and the gas phase portion G is removed by cooling. It is preferable to increase the amount of heat.

  By increasing the temperature of the slurry part S during the operation of the bubble column type slurry bed reactor 10, the conversion rate of carbon monoxide is maintained at a predetermined level against the decrease in the activity of the FT synthesis catalyst over time. The productivity of hydrocarbon oil can be maintained. And when raising the temperature of the slurry part S, the cooling by the 2nd cooling means H4 is strengthened, and the discharge amount L10 by the temperature rise of the slurry part S is increased by increasing the quantity of heat removed by cooling the gas phase part G. It is possible to suppress changes in the amount of gaseous hydrocarbons discharged from the gas and the composition thereof. As a specific method for increasing the amount of heat removed by cooling the gas phase portion G by enhancing the cooling by the second cooling means H4, for example, when the second cooling means H4 is a cooling pipe, For example, a method of increasing the flow rate of the cooling medium to be circulated or decreasing the temperature of the cooling medium to be supplied can be used.

  When increasing the amount of heat to be removed by cooling the gas phase portion G, the gas phase portion G is cooled so that the temperature at the outlet of the gas phase portion G is maintained at the same temperature as before the temperature of the slurry portion S is increased. You may do it. As the temperature of the slurry part S rises, the temperature of gaseous hydrocarbons, water vapor and unreacted synthesis gas moving from the slurry part S to the gas phase part G rises, and the amount of gaseous hydrocarbons moving increases. To do. Therefore, when the temperature of the slurry part S is increased, in order to keep the temperature of the outlet of the gas phase part G at the same temperature as before the temperature of the slurry part S is raised, the amount of heat removed by cooling the gas phase part G Is increased more than before the temperature of the slurry portion S is increased.

  The cooling of the gas phase part G by the second cooling means H4 may be performed such that the temperature of the outlet of the gas phase part G is 3 to 40 ° C., preferably 5 to 30 ° C. lower than the temperature of the slurry part S. desirable.

  When the temperature at the outlet of the gas phase part G is not lower by 3 ° C. or more than the temperature of the slurry part S, the amount of gaseous hydrocarbons discharged from the discharge line L10 due to the temperature rise of the slurry part S and It tends to be difficult to sufficiently suppress an increase in the content of the wax fraction in the gaseous hydrocarbon. On the other hand, when the temperature at the outlet of the gas phase part G becomes lower than 40 ° C. with respect to the temperature of the slurry part S, the amount of gaseous hydrocarbons condensed and returned to the slurry part S increases. The amount of liquid hydrocarbons extracted as heavy hydrocarbon oil increases, and the load on the filter F increases. Further, the cooling capacity required by the second cooling means H4 becomes excessive, and the equipment cost increases.

  The gas phase section G may be cooled by the second cooling means H4 from the start-up of the operation of the FT synthesis reaction by the bubble column type slurry bed reactor 10, or the FT synthesis catalyst as the operation time elapses. In order to compensate for this, the reaction temperature may be increased to a predetermined temperature. The above-mentioned “increasing the temperature of the slurry part S in the reactor C2 during the operation of the bubble column type slurry bed reactor 10 and increasing the amount of heat removed by cooling the gas phase part G” means slurry. This includes a case where the gas phase portion G is not cooled before the temperature of the portion S is increased, and the cooling of the gas phase portion G is started when the temperature of the slurry portion S is increased.

<Upgrading process>
In the upgrading process, the heavy hydrocarbon oil and light hydrocarbon oil obtained in the FT synthesis reaction process are subjected to hydrotreating (hydrorefining, hydroisomerization, hydrocracking) and fractionation, and impurities ( Oxygenated compounds such as olefins and alcohols) are converted to saturated hydrocarbons and removed, part of normal paraffins is converted to isoparaffins, or the carbon number of hydrocarbons is reduced, resulting in damage to the engine, which is the main target. A middle distillate (kerosene / light oil distillate) that is excellent in low-temperature fluidity is not produced in high yield.

  The heavy hydrocarbon oil discharged from the heavy hydrocarbon oil discharge line L6 is removed from the heavy hydrocarbon oil and hydrogen together with hydrogen gas after the naphtha fraction and middle fraction contained in a small amount are removed by fractionation if necessary. It is supplied to the hydrocracking apparatus C4 and used for hydrocracking. In this hydrocracking, the wax fraction having approximately 22 or more carbon atoms is decomposed into middle fractions having approximately 11 to 21 carbon atoms. Simultaneously with hydrocracking, olefins and oxygenates are converted to saturated hydrocarbons, and a portion of normal paraffins are hydroisomerized and converted to isoparaffins. A part of the wax fraction is inevitably excessively decomposed into a naphtha fraction or a hydrocarbon gas. When heavy hydrocarbon oil is fractionated before being subjected to hydrocracking, the naphtha fraction and middle fraction separated from the wax fraction by fractional distillation are mixed with light hydrocarbon oil to produce hydrogen. It is used for chemical purification.

  As the hydrocracking catalyst used in the reactor of the heavy hydrocarbon oil hydrocracking apparatus C4, a known catalyst is used, and the inorganic carrier having solid acidity has a periodic table of elements having hydrogenation activity in the eighth to eighth periods. A catalyst on which a metal belonging to Group 10 is supported is preferably used. Here, the periodic table of elements means a periodic table of long-period elements based on the provisions of IUPAC (International Pure Applied Chemistry Association).

  Suitable inorganic carriers having solid acidity constituting the hydrocracking catalyst include zeolites such as ultra-stable Y-type (USY) zeolite, Y-type zeolite, mordenite and β-zeolite, silica alumina, silica zirconia, and alumina boria. And those composed of one or more inorganic compounds selected from amorphous composite metal oxides. Furthermore, the inorganic carrier is more preferably a composition comprising USY zeolite and one or more amorphous composite metal oxides selected from silica alumina, alumina boria and silica zirconia. More preferred is a composition comprising alumina boria and / or silica alumina. The inorganic carrier may further contain a binder.

  Specific examples of the metals in Group 8 to 10 of the periodic table having hydrogenation activity supported on an inorganic carrier include cobalt, nickel, rhodium, palladium, iridium, and platinum. Among these, it is preferable to use the metal chosen from nickel, palladium, and platinum individually by 1 type or in combination of 2 or more types. Further, cobalt and nickel may be used in combination with molybdenum and tungsten which are metals of Group 6 of the periodic table.

  In the heavy hydrocarbon oil hydrocracking apparatus C4, the production of naphtha fraction and hydrocarbon gas having approximately 10 or less carbon atoms due to excessive cracking is suppressed, and the yield of middle fraction is maximized. It is preferable to hydrocrack the wax fraction. For this purpose, for example, the ratio (mass ratio) of hydrocarbons having 21 or less carbon atoms produced from hydrocarbons having 22 or more carbon atoms is taken as the decomposition rate, and this decomposition rate is 40 to 90%, preferably 50 to 80%. It is desirable.

Although the reaction conditions in the heavy hydrocarbon oil hydrocracking apparatus C4 are not limited, the reaction temperature is 200 to 370 ° C., the hydrogen partial pressure is 0.5 to 12 MPa, and the liquid space velocity (LHSV) is 0.1 to 0.1. The condition of 10.0 h ⁻¹ and the hydrogen / oil ratio is 50 to 1000 NL / L.

  The hydrocracking product flowing out from the reactor of the heavy hydrocarbon oil hydrocracking apparatus C4 is preferably provided in a multistage stage after the reactor by a cooler and a gas-liquid separation tank (not shown). It is separated into gas components and liquid hydrocarbons composed of unreacted hydrogen gas and hydrocarbon gas generated by excessive decomposition.

The light hydrocarbon oil discharged from the light hydrocarbon oil discharge line L14 is subjected to light hydrocarbon oil hydrorefining together with hydrogen gas after removing hydrocarbon gas of 4 or less carbon atoms contained in a small amount by fractional distillation if necessary. It is supplied to the apparatus C6 and used for hydrorefining. In this hydrorefining, oxygenated compounds such as olefins and alcohols contained as impurities in light hydrocarbon oils are converted to saturated hydrocarbons by hydrorefining, and some of the normal paraffins are isoparaffins by hydroisomerization. Converted into In this hydrorefining, hydrocracking is inevitably partly accompanied, but it is preferable to suppress the progress of hydrocracking from the viewpoint of increasing the yield of middle distillate.

  As the hydrorefining catalyst used in the reactor of the light hydrocarbon oil hydrorefining apparatus C6, a known catalyst having activity in hydrorefining and hydroisomerization is used, and hydrogen is added to the inorganic carrier having solid acidity. A catalyst on which a metal belonging to Groups 8 to 10 of the periodic table of elements having an activating activity is supported is preferably used.

  Examples of the inorganic carrier constituting the hydrorefining catalyst include metal oxides such as alumina, silica, titania, zirconia, and boria, a mixture of two or more of these metal oxides, or silica alumina, silica zirconia, alumina zirconia, A composite metal oxide composed of a combination of the above metal oxides such as alumina boria may be used. The inorganic carrier is a composite metal oxide having solid acidity such as silica alumina, silica zirconia, alumina zirconia, alumina boria, etc. from the viewpoint of efficiently proceeding hydroisomerization of normal paraffin simultaneously with hydrorefining. It is preferable. In addition, the inorganic carrier may contain zeolite, but from the viewpoint of suppressing hydrocracking, it is preferable to reduce the blending amount when containing zeolite. The inorganic carrier may further contain a binder.

  Specific examples of the metals in Group 8 to 10 of the periodic table having hydrogenation activity supported on an inorganic carrier include cobalt, nickel, rhodium, palladium, iridium, and platinum. Among these, it is preferable to use the metal chosen from nickel, palladium, and platinum individually by 1 type or in combination of 2 or more types. Further, cobalt and nickel may be used in combination with molybdenum and tungsten which are metals of Group 6 of the periodic table.

Although the reaction conditions in the light hydrocarbon oil hydrotreating apparatus C6 are not limited, the reaction temperature is 200 to 370 ° C., the hydrogen partial pressure is 0.5 to 12 MPa, and the liquid space velocity (LHSV) is 0.1 to 10 0.0h ⁻¹ , and the hydrogen / oil ratio is exemplified by conditions such as 50 to 1000 NL / L.

  The hydrorefined product flowing out from the reactor of the light hydrocarbon oil hydrorefining apparatus C6 is unreacted hydrogen gas by a cooler and a gas-liquid separation tank (not shown) disposed downstream of the reactor. And a gas component composed of a hydrocarbon gas produced by partially hydrocracking and a liquid hydrocarbon.

  Liquid hydrocarbons flowing out from the heavy hydrocarbon oil hydrocracking unit C4 and light hydrocarbon oil hydrotreating unit C6 through the transfer lines L16 and L18, respectively, are mixed in the transfer line L20 and supplied to the rectifying unit C8. Is fractionated. By this fractionation, a naphtha fraction is extracted from the extraction line L22, and the dissolved hydrocarbon gas having 4 or less carbon atoms is preferably removed by a stabilizer and stored in a storage tank. A kerosene fraction is extracted from the extraction line L24, and a light oil fraction is extracted from the extraction line L26, and each is stored in a storage tank. On the other hand, undecomposed wax is extracted from the bottom of the rectifying column constituting the rectifying apparatus C8, and this undecomposed wax is upstream of the heavy hydrocarbon oil hydrocracking apparatus C4 by the undecomposed wax recycling line L28. Recycled and mixed with freshly supplied heavy hydrocarbon oil and again subjected to hydrocracking.

  As described above, in the upgrading process, by purifying and separating the hydrocarbon oil composed of the heavy hydrocarbon oil and the light hydrocarbon oil obtained by the FT synthesis process, the sulfur content and the aromatic carbonization are obtained in a high yield. Middle distillate (kerosene and light oil distillate) with low temperature fluidity, including isoparaffin, and virtually free from environmentally hazardous substances such as hydrogen, impurities removed and no damage to the engine A naphtha fraction is obtained.

(Confirmation test)
In the FT synthesis reaction using the bubble column type slurry bed reactor 10, the reaction temperature (temperature of the slurry part S) is 220 ° C., the gas phase part G is not cooled, and the temperature at the outlet of the gas phase part G is 220 ° C. The FT synthesis reaction was run. Next, the temperature of the slurry part S is set to 230 ° C., the gas phase part G is not cooled, the temperature at the outlet of the gas phase part G is set to 230 ° C., and the temperature of the slurry part S remains at 230 ° C. An operation was performed in which the temperature at the outlet of the gas phase part G was 220 ° C. by cooling the gas phase part G by means H4. Further, the temperature of the slurry part S is set to 240 ° C., the gas phase part G is not cooled, the temperature at the outlet of the gas phase part G is set to 240 ° C., and the temperature of the slurry part S is kept at 240 ° C. An operation was performed in which the temperature at the outlet of the gas phase part G was 230 ° C. and 220 ° C., respectively, by cooling the gas phase part G by means H4.

  In each of the above operations, the amount of light hydrocarbon oil discharged from the light hydrocarbon oil discharge line L14 per unit time and the heavy hydrocarbon oil discharged from the heavy hydrocarbon oil discharge line L6 per unit time. The ratio to the amount of was confirmed, and the results are shown in Table 1 below. In addition, the ratio of the discharge amount of light hydrocarbon oil and heavy hydrocarbon oil is shown by each mass part when the sum of the discharge amount (mass) per unit time of both hydrocarbon oils is 100 mass parts.

  As shown in Table 1, when the gas phase part G is not cooled, the ratio of the light hydrocarbon oil is remarkably increased as the temperature of the slurry part S increases, but the temperature of the gas phase part G is adjusted by cooling. Thus, an increase in the ratio of light hydrocarbon oil can be relatively suppressed.

  Moreover, the composition (carbon number distribution) of each of the light hydrocarbon oil and heavy hydrocarbon oil obtained in each operation was analyzed. The results are shown in Tables 2-7 below. Table 2 shows that when the temperature of the slurry part S and the temperature of the gas phase part G are both 220 ° C., Table 3 and Table 4 show the temperature of the slurry part S of 230 ° C. and the temperature of the gas phase part G, respectively. Tables 5 to 7 show light hydrocarbon oils when the temperature of the slurry part is 240 ° C and the temperatures of the outlets of the gas phase part G are 240 ° C, 230 ° C, and 220 ° C, respectively. The composition of heavy hydrocarbon oil is shown respectively.

  From the comparison of Table 2, Table 3 and Table 5, when the temperature of the slurry part S is raised and the gas phase part G is not cooled, the composition of hydrocarbons produced by the FT synthesis reaction changes, and the lightness It can be seen that the content of hydrocarbons belonging to the wax fraction in the hydrocarbon oil increases. And as shown in Table 4, Table 6, and Table 7, the content of the hydrocarbons belonging to the wax fraction in the light hydrocarbon oil decreases by adjusting the temperature at the outlet of the gas phase part G by cooling. I understand that.

  As a result of the above confirmation test, when the temperature of the slurry part S is increased, the gaseous hydrocarbons discharged from the gas phase part G by cooling the gas phase part G by the second cooling means H4, and consequently It became clear that the amount of light hydrocarbon oil discharged and changes in its composition could be suppressed.

  The preferred embodiments of the hydrocarbon oil production method, the bubble column type slurry bed reactor and the hydrocarbon oil production system according to the present invention have been described above, but the present invention is not necessarily limited to the above-described embodiments. is not.

  For example, in the above embodiment, natural gas is used as a raw material for syngas production in the GTL process. However, a non-gaseous hydrocarbon raw material such as asphalt or residual oil may be used. Moreover, in the said embodiment, although the kerosene fraction and the light oil fraction were fractionated as another fraction in the rectification apparatus C8, you may fractionate these as one fraction (middle fraction).

DESCRIPTION OF SYMBOLS 10 ... Bubble column type slurry bed reactor, C2 ... Bubble column type slurry bed reactor, H2 ... First cooling means, H4 ... Second cooling means, S ... Slurry part, G ... gas phase part, D2 ... catalyst separation tank, D4 ... gas / liquid / oil / water separation tank, C4 ... heavy hydrocarbon oil hydrocracking apparatus, C6 ... light hydrocarbon oil hydrogenation Refiner, C8 ... Rectifier, 100 ... Hydrocarbon oil production system.

Claims (5)

A method for producing a hydrocarbon oil by using a bubble column type slurry bed reactor to obtain a hydrocarbon oil by a Fischer-Tropsch synthesis reaction,
In the reactor equipped with the bubble column type slurry bed reactor, having a slurry part containing catalyst particles and liquid hydrocarbons, and a gas phase part located above the slurry part,
The gas phase part is cooled, condensed a part of the gaseous hydrocarbon in the gas phase part and returned to the slurry part ,
As the temperature of the slurry part rises, the amount of heat removed by cooling the gas phase part is increased,
A method for producing a hydrocarbon oil, wherein the gas phase part is cooled such that the temperature at the outlet of the gas phase part is 3 to 40 ° C lower than the temperature of the slurry part .   The method for producing hydrocarbon oil according to claim 1, wherein the gas phase part is cooled by a cooling pipe in which a cooling medium is circulated. A reactor in which a slurry part containing catalyst particles and liquid hydrocarbons and a gas phase part located above the slurry part are formed, and a cooling means for cooling the gas phase part ,
The cooling means increases the amount of heat removed by cooling the gas phase portion as the temperature of the slurry portion increases, and the temperature at the outlet of the gas phase portion is 3 to 40 ° C. with respect to the temperature of the slurry portion. you cool the gas phase portion to be lower, the Fischer-Tropsch synthesis reaction for bubble column slurry bed reactor. The bubble column type slurry bed reactor according to claim 3 , wherein the cooling means is a cooling pipe in which a cooling medium is circulated. A system for producing hydrocarbon oil, comprising the bubble column type slurry bed reactor according to claim 3 or 4 .

Images