JP2013060509A - Desulfurization method for hydrocarbon mixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desulfurization method for a hydrocarbon mixture, capable of efficiently removing a sulfur compound included in a hydrocarbon mixture containing 10 wt.% or more of diolefins, and capable of improving the productivity by prolonging the life of a catalyst used for the desulfurization.SOLUTION: The desulfurization method for a hydrocarbon mixture comprises a step of removing at least a part of a sulfur compound included in a hydrocarbon mixture containing 10 wt.% or more of diolefins using a catalyst including as the main component a supporting type nickel subjected to reduction at 230-500°C in a gas phase reducing atmosphere.

Description

  The present invention relates to a method for desulfurizing a sulfur compound contained in a hydrocarbon mixture containing 10% by weight or more of diolefins.

  Isoprene which is a main raw material such as synthetic rubber is usually obtained by extractive distillation of isoprene contained in a C5 fraction discharged from an ethylene cracker at an ethylene center.

  In the process of extractive distillation of isoprene contained in the C5 fraction, after cyclopentadiene is dimerized (to be converted to dicyclopentadiene) from the C5 fraction, light components such as pentane and pentenes, and pentadienes (dicyclohexane) are obtained. Heavy components such as pentadiene and 1,3-pentadiene) and acetylenes are removed by two distillation columns, respectively, and diolefins (including 1,3-pentadiene) and the remaining components are extracted in the next extractive distillation column. By removing the acetylenes and then distilling the residue, isoprene can be efficiently obtained from the bottom of the column.

  At this time, C5 raffinate, which is an extraction residual oil, is obtained. The C5 raffinate can be returned to the ethylene center and used mainly as a raw material for gasoline bases and ethylene crackers. The removed dicyclopentadiene, 1,3-pentadiene, and the like can be used as raw materials for resins and the like.

  By the way, since the sulfur-containing component is contained in the C5 fraction at a concentration of several weight ppm to several hundred weight ppm, the sulfur-containing component is also contained in the C5 raffinate, which is an extraction residual oil, from several ppm to several ppm. It will contain 100 ppm by weight.

  Therefore, when C5 raffinate is used as a raw material for ethylene crackers, if C5 raffinate contains a large amount of sulfur-containing components as described above, the diene removal tower installed in the refining section of the ethylene plant in the ethylene center. There is a problem that the catalyst in the inside deteriorates significantly, the consumption of hydrogen in the refining section increases significantly, and the profitability of the ethylene plant deteriorates. In addition, since the catalyst in the diene removal tower is poisoned by the sulfur-containing component, if a large amount of the sulfur-containing component is contained, it becomes necessary to regenerate or replace the poisoned catalyst. There is also a problem that the running cost deteriorates.

  For this reason, C5 raffinate containing a large amount of sulfur-containing components is problematic in terms of quality and cost, so it cannot be used as a hydrocarbon raw material for ethylene crackers and is incinerated as a fuel. Currently.

  On the other hand, due to the recent increase in interest in environmental issues, there is a concern about an increase in carbon dioxide, and the need to effectively use crude oil is increasing, so C5 raffinate is not burned and used as a hydrocarbon feedstock. It is desired to use it.

  Therefore, in order to use C5 raffinate containing a sulfur-containing component of several ppm to several hundred ppm by weight, particularly as a hydrocarbon raw material for ethylene crackers, it is necessary to remove the sulfur-containing component as much as possible.

  Further, C5 raffinate contains diolefins such as isoprene, dicyclopentadiene and 1,3-pentadiene at a level of several tens of weight% as surplus components for the demand for products made from diolefins. Yes.

  Therefore, in order to use C5 raffinate as a hydrocarbon raw material for ethylene crackers, sulfur-containing components are efficiently and as much as possible from C5 raffinate containing several tens of weight% of diolefins. Need to be removed.

  On the other hand, as a method for removing sulfur-containing components, a method of hydrodesulfurization in a liquid phase at high temperature and high pressure using a catalyst such as Co-Mo / alumina or Ni-Mo / alumina is widely used. ing. In such a hydrodesulfurization method, by performing hydrodesulfurization under high pressure, a sulfur-containing component is mainly decomposed into hydrogen disulfide without hydrogenating double bonds of diolefins as much as possible. This is a method for separating or absorbing hydrogen sulfide.

  However, since this hydrodesulfurization method is a reaction in the liquid phase under high temperature and high pressure, when used for C5 raffinate containing a high concentration of diolefins, the Diels-Alder reaction proceeds. Therefore, hydrogenation of diolefins proceeding simultaneously with desulfurization may be extremely difficult to proceed. In this case, the C5 raffinate after desulfurization contains a large amount of diolefins, although the sulfur-containing component is reduced, so that it can be used as a hydrocarbon raw material for ethylene crackers in terms of quality. There is also a problem in terms of cost.

  Further, for example, Patent Document 1 discloses a desulfurization method using a nickel catalyst for a sulfur-containing component contained in kerosene and liquefied petroleum gas (LPG). However, in this method, when used for a material containing a high concentration of diolefins such as C5 raffinate, the desulfurization performance was insufficient.

JP 2010-1480 A

  The present invention has been made in view of such circumstances, and in a desulfurization method for removing a sulfur compound contained in a hydrocarbon mixture from a hydrocarbon mixture containing 10% by weight or more of a diolefin, a sulfur compound is provided. An object of the present invention is to provide a hydrocarbon mixture desulfurization method capable of improving productivity by efficiently removing the catalyst and extending the life of the catalyst used for desulfurization.

  As a result of intensive studies to achieve the above object, the present inventors have carried out a reduction of a sulfur compound contained in a hydrocarbon mixture containing 10% by weight or more of diolefins at 230 to 500 ° C. By removing the main component of the catalyst in the gas phase and in a reducing atmosphere, sulfur compounds can be removed efficiently, and the life of the catalyst used for desulfurization can be extended. The inventors have found that the properties can be improved, and have completed the present invention.

  That is, according to the present invention, a catalyst mainly composed of supported nickel obtained by reducing at least a part of a sulfur compound contained in a hydrocarbon mixture containing 10% by weight or more of diolefins at 230 to 500 ° C. Is used to remove the hydrocarbon mixture in a gas phase and in a reducing atmosphere.

In the present invention, the sulfur compound is preferably removed under conditions of a pressure of 0.3 MPa or less and a temperature of 180 to 400 ° C.
In the present invention, the hydrocarbon mixture is preferably a thermal decomposition product of naphtha.

  According to the present invention, productivity can be improved by efficiently removing sulfur compounds contained in a hydrocarbon mixture containing 10% by weight or more of diolefins and extending the life of a catalyst used for desulfurization. Can do.

Hereinafter, the present invention will be described in detail.
The hydrocarbon mixture desulfurization method of the present invention is mainly composed of supported nickel obtained by reducing at least a part of a sulfur compound contained in a hydrocarbon mixture containing 10% by weight or more of diolefins at 230 to 500 ° C. Is removed in a gas phase and in a reducing atmosphere.

<Hydrocarbon mixture>
First, the hydrocarbon mixture used in the present invention will be described. The hydrocarbon mixture used in the present invention is a mixture of hydrocarbon compounds, and contains 10% by weight or more of diolefins and a sulfur compound.

  The content of diolefins contained in the hydrocarbon mixture used in the present invention is 10% by weight or more, preferably 30% by weight or more, more preferably 50% by weight or more. Moreover, the upper limit of the content rate of diolefins is although it does not specifically limit, Preferably it is 80 weight% or less, More preferably, it is 70 weight% or less. When the content ratio of diolefins is in the above range, the effect of the present invention can be made more remarkable. In addition, although it does not specifically limit as diolefins contained in the hydrocarbon mixture used by this invention, For example, isoprene, cyclopentadiene, dicyclopentadiene, 1, 3-pentadiene, etc. are mentioned.

  Further, the content ratio of the sulfur compound contained in the hydrocarbon mixture used in the present invention is preferably 10 ppm by weight or more, more preferably 30 weights at the lower limit with respect to the whole hydrocarbon mixture in terms of sulfur atoms. The upper limit is preferably 500 ppm by weight or less, and more preferably 300 ppm by weight or less. When the content ratio of the sulfur compound is in the above range, the effect of the present invention can be made more remarkable. The sulfur compound contained in the hydrocarbon mixture used in the present invention includes a general compound contained as an impurity in the hydrocarbon compound, and specific examples thereof include sulfur, thiols, sulfides, and thiophenes. And carbon disulfide.

  In the present invention, such a hydrocarbon mixture is not particularly limited, and examples thereof include a thermal decomposition product of naphtha, particularly C5 raffinate. C5 raffinate is a residue obtained by separating at least a portion of isoprene by extractive distillation from a C5 fraction mainly composed of an organic compound having 5 carbon atoms, which is produced as a by-product when pyrolyzing naphtha to produce ethylene. This is a fraction obtained as an oil. When a naphtha pyrolysis product, particularly C5 raffinate, is used as the hydrocarbon mixture, the effect of the present invention can be made more remarkable.

  Here, the C5 raffinate is a fraction obtained as an extraction residue after at least a part of isoprene is separated by extractive distillation from a C5 fraction mainly composed of an organic compound having 5 carbon atoms. When extractive distillation is performed, a portion of isoprene may remain. Therefore, C5 raffinate may contain isoprene.

  The C5 raffinate may be a fraction obtained as an extraction residue after at least a part of isoprene is separated by extractive distillation. In addition to isoprene, dicyclopentadiene and 1,3-pentadiene It is preferably a fraction obtained as an extraction residual oil after each of the three components is separated by extractive distillation. Even in this case, when each component is extracted and distilled, a part of each of the three components of isoprene, dicyclopentadiene, and 1,3-pentadiene may remain. Therefore, C5 raffinate may contain isoprene, dicyclopentadiene, and 1,3-pentadiene. Furthermore, as C5 raffinate, what is not expected to be used (surplus) among separated isoprene, dicyclopentadiene, and 1,3-pentadiene is included in the extracted residual oil.

  In addition, as a method for extracting and distilling isoprene, dicyclopentadiene, and 1,3-pentadiene from a C5 fraction containing an organic compound having 5 carbon atoms as a main component, for example, known methods such as GPI (Nippon Zeon Corporation) A method is mentioned.

  Next, the desulfurization method of the present invention will be described.

<Gasification process>
First, a hydrocarbon mixture containing 10% by weight or more of diolefin is gasified by heating or the like. Preferably, a gas phase pyrolysis step is further performed in which at least a part of the C10 diolefins contained in the gasified hydrocarbon mixture is pyrolyzed.

Since the gas phase pyrolysis step is a step of thermally decomposing at least part of the C10 diolefins, when a C5 raffinate containing C10 diolefins is used as the hydrocarbon mixture. It is preferable to perform a desulfurization step described later after the vapor phase pyrolysis step described below. However, on the other hand, when a hydrocarbon mixture containing almost no C10 diolefin is used as the hydrocarbon mixture, a desulfurization step described later is performed without going through a gas phase pyrolysis step described below. It is preferable.
In the following, a case where a gas phase pyrolysis step, which is a preferred embodiment, is performed will be described as an example.

  In the gas phase pyrolysis step, first, the hydrocarbon mixture is gasified by heating. For example, as a method of heating and gasifying the hydrocarbon mixture, the hydrocarbon mixture is supplied to the preheater provided in the reactor and preheated, and then the vaporizer joined to the preheater and the pipe is connected. The method of supplying and heating is mentioned. The heating temperature is usually 180 to 400 ° C, preferably 190 ° C to 350 ° C.

  In addition, when gasifying a hydrocarbon mixture, a diluent, an entrainer (additive), etc. can also be added.

  Such a diluent or entrainer is not particularly limited as long as it does not inhibit the thermal decomposition reaction in the gas phase thermal decomposition process, the desulfurization reaction in the desulfurization process described later, and the hydrogenation reaction in the hydrogenation process described later. Not.

  Specific examples of the diluent include inert gases such as nitrogen gas, helium gas and argon gas; alkanes having 5 to 10 carbon atoms such as n-pentane, n-hexane and n-heptane; cyclopentane and cyclohexane C5-C10 cycloalkanes such as cycloheptane; C5-C10 alkenes such as 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1-heptene; cyclopentene, cyclohexene And C 5-10 cycloalkenes such as cycloheptene; and the like. Among these, those having a boiling point in the range of 40 to 300 ° C are preferable.

  As the entrainer, a boiling point of 150 ° C. or higher is desirable because it is necessary to dissolve high boiling point impurities. Specific examples include mineral and synthetic lubricating oils and heat transfer oils.

  Although the usage-amount of a diluent and an entrainer is not specifically limited, Usually, it is 0-3000 weight part with respect to 100 weight part of hydrocarbon mixtures, Preferably it is 0-2000 weight part, More preferably, it is 0-1000 weight part. is there. If too much diluent and entrainer is used, it may be disadvantageous in terms of process efficiency.

  Next, preferably, the gasified hydrocarbon mixture is supplied to a pyrolyzer, and a treatment for pyrolyzing at least a part of the diolefins having 10 carbon atoms contained in the gasified hydrocarbon mixture is performed. The diolefins having 10 carbon atoms include, for example, dicyclopentadiene. In this case, dicyclopentadiene contained in the gasified hydrocarbon mixture is decomposed into cyclopentadiene by a thermal decomposition reaction. Become. As described above, the hydrogenation reaction in the hydrogenation step described later is performed even when the hydrocarbon mixture contains a high concentration of diolefins having 10 carbon atoms by performing pyrolysis on the gasified hydrocarbon mixture. Proceeds efficiently, and as a result, a hydrocarbon mixture from which diolefins and olefins are efficiently removed can be finally obtained.

  The temperature at the time of thermal decomposition is usually 200 to 500 ° C, preferably 310 to 450 ° C. The pressure in the pyrolysis is a gauge pressure, and the upper limit is preferably 0.5 MPa or less, more preferably 0.3 MPa or less, and the lower limit is preferably 0 MPa or more.

  In addition, as the thermal decomposition time, for example, when thermal decomposition is performed in the thermal decomposer, the residence time (gas standard) in the thermal decomposer may be set in a range where a predetermined decomposition rate can be obtained, Although not particularly limited, it is preferably 0.01 to 60 seconds, more preferably 0.05 to 40 seconds.

  And by such a gaseous-phase pyrolysis process, the gasification hydrocarbon mixture by which at least one part of C10 diolefins contained in the hydrocarbon mixture was decomposed | disassembled can be obtained.

  By such a gas phase pyrolysis step, the content ratio of the C10 diolefins in the gasified hydrocarbon mixture is preferably 1% by weight or less, more preferably 0.5% by weight or less, and particularly preferably 0%. It can be reduced to 1% by weight or less.

<Desulfurization process>
Next, a desulfurization step of removing at least a part of the sulfur compound contained in the mixture is performed on the gasified hydrocarbon mixture that has been gasified by the gasification step described above.

  In the desulfurization step, a catalyst mainly composed of supported nickel that has been previously reduced at 230 to 500 ° C. is used as the desulfurization catalyst. Usually, the above-described gasification is applied to a desulfurization reactor filled with such a desulfurization catalyst. The process is preferably carried out by supplying a gasified hydrocarbon mixture which has been subjected to gas phase pyrolysis by a gas phase pyrolysis process.

  As a catalyst having supported nickel as a main component (hereinafter, referred to as “supported nickel catalyst” as appropriate), a compound formed by supporting nickel as a metal on a supported inorganic compound as a carrier is used as a main component. Containing catalyst. Specific examples of the supported inorganic compound as the carrier include silica, alumina, boria, silica-alumina, diatomaceous earth, white clay, clay, magnesia, magnesia-silica, titania, zirconia and the like. Among these, magnesia-silica and diatomaceous earth are preferable, and diatomaceous earth is more preferable from the viewpoint of higher desulfurization performance.

  In addition, as the metal supported on the carrier, even nickel alone can achieve sufficient desulfurization performance, but in addition to nickel, palladium, platinum, ruthenium, copper can be used because the desulfurization performance can be further enhanced. , One containing at least one metal selected from the group consisting of chromium, molybdenum, zinc, and cobalt may be used. In this case, the content ratio of nickel is preferably 60 to 99.5% by weight, more preferably 80 to 99% by weight, and still more preferably 90 to 95% by weight with respect to the entire metal supported on the carrier. It is.

  Furthermore, the shape of the supported nickel catalyst is not particularly limited, and is generally a pellet shape, a spherical shape, a cylindrical shape, a ring shape, or the like. Further, the particle size of the catalyst is not particularly limited, and an optimal value may be selected depending on the inner diameter of the desulfurization reactor, but the average particle size of the catalyst used in the present invention is preferable from the viewpoint of efficient desulfurization reaction. Is 1 to 40 mm, more preferably 2 to 20 mm.

  In the present invention, as the supported nickel catalyst as the desulfurization catalyst, one that has been previously reduced at 230 to 500 ° C. is used. By carrying out the reduction treatment under such conditions, the supported nickel catalyst can be activated, thereby improving the efficiency of removing sulfur compounds in the desulfurization process, and extending the life of the supported nickel catalyst. As a result, productivity can be improved.

  The method for reducing the supported nickel catalyst as the desulfurization catalyst in advance is not particularly limited. For example, the supported nickel catalyst is placed in a desulfurization reactor, and hydrogen is added to the desulfurization reactor containing the supported nickel catalyst. Examples include a method of heating the supported nickel catalyst in the desulfurization reactor to 230 to 500 ° C. by heating the desulfurization reactor while flowing a reducing gas.

  The heating temperature of the supported nickel catalyst when performing the reduction treatment is 230 to 500 ° C, preferably 250 to 450 ° C, more preferably 300 to 400 ° C. When the heating temperature is too low, the activation of the catalyst becomes insufficient, and the above-described effects are hardly obtained. On the other hand, if the heating temperature is too high, the pores of the supported nickel catalyst are blocked by heating, and the catalytic activity is lowered.

  Further, the heating time of the supported nickel catalyst in performing the reduction treatment is not particularly limited, but is preferably 1 hour or longer, more preferably 3 hours or longer. By setting the heating time within this range, the supported nickel catalyst can be sufficiently activated by the reduction treatment.

  In addition, the hydrogen gas space velocity (the value obtained by dividing the total flow rate of hydrogen gas per hour by the filling volume of the catalyst (based on the empty cylinder), hereinafter referred to as “GHSV”) during the reduction treatment is particularly high. Although not limited, 100-10000 / hour is preferable and 200-5000 / hour is more preferable.

  In the desulfurization step, the desulfurization reactor to be used is not particularly limited, but a multitubular fixed bed flow reactor is preferable. Further, the inner diameter of the reaction tube of the multi-tube fixed bed flow reactor is preferably 6 to 100 mm, more preferably 10 to 70 mm, and the length of the reaction tube is preferably 0.1 to 10 m, more preferably. 0.2-7 m.

  In the present invention, the desulfurization reaction in the desulfurization step is performed in a reducing atmosphere while the hydrocarbon mixture is gasified. That is, it is performed under conditions of a gas phase and a reducing atmosphere. By carrying out under gas phase conditions, the reactivity with the reducing gas used at this time is improved. Note that hydrogen gas can be used as the reducing gas, and by performing the desulfurization reaction in a hydrogen gas atmosphere, the sulfur compound can be removed in the desulfurization step of the hydrocarbon mixture containing a relatively large amount of diolefins. The efficiency can be improved, and the life of the supported nickel catalyst can be extended. As a result, the productivity can be improved. The hydrogen gas space velocity (GHSV) when the desulfurization reaction is performed in a hydrogen gas atmosphere is not particularly limited, but is preferably 100 to 10,000 / hour, and more preferably 200 to 5000 / hour.

  In particular, in the present invention, the desulfurization reaction is performed in a reducing atmosphere using a supported nickel catalyst that has been previously reduced at 230 to 500 ° C. as a catalyst, and the hydrocarbon mixture is gasified. Thus, even when a hydrocarbon mixture containing a relatively large amount of diolefins of 10% by weight or more is used, the desulfurization reaction can be carried out satisfactorily. Moreover, according to this invention, in addition to being able to perform a desulfurization reaction favorably, the hydrogenation reaction of a hydrocarbon mixture can also be advanced. That is, in the present invention, in the desulfurization step, hydrogen that hydrogenates at least a part of at least one carbon-carbon double bond selected from diolefins and olefins contained in the hydrocarbon mixture simultaneously with desulfurization. The reaction can proceed.

  The temperature of the desulfurization reaction is not particularly limited, but is preferably 180 to 400 ° C, more preferably 190 to 350 ° C, and still more preferably 200 to 330 ° C, from the viewpoint that the desulfurization reaction proceeds efficiently.

  The pressure of the desulfurization reaction is a gauge pressure, and the upper limit is preferably 0.3 MPa or less, more preferably 0.1 MPa or less, still more preferably 0.05 MPa or less, and the lower limit is preferably 0 MPa or more. If the pressure of the desulfurization reaction is too high, the component (for example, cyclopentadiene) pyrolyzed in the gas phase pyrolysis step contained in the gasified hydrocarbon mixture undergoes a dimerization reaction, and carbon before pyrolysis There is a problem of returning to several tens of diolefins (for example, dicyclopentadiene). In particular, when a hydrocarbon mixture containing 10% by weight or more of dicyclopentadiene is used, such a tendency becomes stronger when the pressure of the desulfurization reaction is excessively increased.

  Furthermore, the gas space velocity (GHSV) of the gasified hydrocarbon mixture of the desulfurization reaction is not particularly limited, but is preferably 50 to 500 / hour, more preferably 100 to 300 / hour.

  By such a desulfurization step, the sulfur compound contained in the hydrocarbon mixture before the desulfurization step can be preferably removed in an amount of 90% by weight or more, more preferably 95% by weight or more in terms of the sulfur atom.

  And in this invention, in the hydrocarbon mixture obtained by performing the desulfurization process which removes a sulfur compound in a gaseous phase and a reducing atmosphere using such a supported nickel catalyst reduced at 230-500 degreeC. In this case, the sulfur compound can be efficiently removed and the life of the supported nickel catalyst can be extended. Therefore, productivity when performing the desulfurization reaction can be improved. In addition, in the present invention, by such a desulfurization step, the hydrogenation reaction can be advanced while the content ratio of the sulfur compound is reduced to the above range.

<Hydrogenation process>
In the present invention, the gasified hydrocarbon mixture subjected to the desulfurization reaction in the above-described desulfurization step is at least one carbon selected from diolefins and olefins contained in the gasified hydrocarbon mixture as necessary. -You may perform the hydrogenation process which hydrogenates at least one part of a carbon double bond.

  In the hydrogenation step, the hydrogenation reaction is preferably performed in the presence of a catalyst. Usually, a gasified hydrocarbon mixture obtained by performing the desulfurization reaction in the above-described desulfurization step in a hydrogenation reactor filled with the catalyst. This is done by supplying Although it does not specifically limit as a catalyst, In this invention, it is preferable to use the catalyst which has supported nickel as a main component.

  As the catalyst mainly composed of supported nickel, for example, the same catalyst as in the above-described desulfurization step can be used. Moreover, as the catalyst having supported nickel as a main component, a catalyst that has been subjected to a reduction treatment in advance as in the above-described desulfurization step may be used.

  In the hydrogenation step, the hydrogenation reactor to be used is not particularly limited, but is preferably a multi-tube fixed bed flow reactor. Further, the inner diameter of the reaction tube of the multi-tube fixed bed flow reactor is preferably 6 to 100 mm, more preferably 10 to 70 mm, and the length of the reaction tube is preferably 0.1 to 10 m, more preferably. 0.3 to 7 m.

  In the hydrogenation step, the hydrogenation reaction is preferably performed in a reducing atmosphere, particularly preferably in a hydrogen gas atmosphere. By performing the hydrogenation reaction in a hydrogen gas atmosphere, the efficiency of the hydrogenation reaction can be further increased. Although the hydrogen gas space velocity (GHSV) when performing a hydrogenation reaction in hydrogen gas atmosphere is not specifically limited, 100-10000 / hour is preferable and 200-5000 / hour is more preferable.

  The temperature of the hydrogenation reaction is not particularly limited, but is preferably 140 to 400 ° C, more preferably 150 to 300 ° C, and still more preferably 160 to 250 ° C, from the viewpoint that the hydrogenation reaction proceeds efficiently.

  The hydrogenation reaction pressure is a gauge pressure, and the upper limit is preferably 0.3 MPa or less, more preferably 0.1 MPa or less, still more preferably 0.05 MPa or less, and the lower limit is preferably 0 MPa or more. . If the pressure of the hydrogenation reaction is too high, the components (for example, cyclopentadiene) pyrolyzed in the gas phase pyrolysis step contained in the gasified hydrocarbon mixture undergo a dimerization reaction, There is a problem that it returns to diolefins having 10 carbon atoms (for example, dicyclopentadiene). And if it returns to diolefins of carbon number 10 before thermal decomposition, hydrogenation in a hydrogenation process will become difficult, As a result, the hydrocarbon mixture with a high content rate of diolefins and olefins will be obtained. It will be finally obtained.

  Furthermore, the gas space velocity (GHSV) of the gasified hydrocarbon mixture of the hydrogenation reaction is not particularly limited, but is preferably 50 to 500 / hour, more preferably 100 to 300 / hour.

  And, by such a hydrogenation step, gasification in which at least a part of at least one carbon-carbon double bond selected from diolefins and olefins contained in the gasified hydrocarbon mixture has been removed. A hydrocarbon mixture can be obtained, and this can be condensed with a heat exchange type cooler or the like to obtain a desulfurized and hydrogenated hydrocarbon mixture.

  According to the present invention, the amount of diolefins and olefins in the hydrocarbon mixture can be appropriately reduced by performing such a hydrogenation step. In particular, according to the present invention, by performing the hydrogenation step after the desulfurization step, the hydrogenation catalyst used in the hydrogenation step can be effectively prevented from being poisoned by the sulfur compound. As a result, the life of the hydrogenation catalyst can be significantly extended.

  In the above example, the gas phase pyrolysis step is performed before the desulfurization step, and the hydrogenation step is performed after the desulfurization step. The addition process is not an essential process. Therefore, it is not always necessary to perform one or both of these.

  However, on the other hand, for example, when a naphtha pyrolysis product, particularly C5 raffinate, is used as the hydrocarbon mixture, the amount of diolefins and olefins in the finally obtained hydrocarbon mixture is effectively reduced. From the viewpoint of being able to reduce the temperature, it is preferable to perform a gas phase pyrolysis step and a hydrogenation step. That is, it is preferable to perform the vapor phase pyrolysis step, the desulfurization step, and the hydrogenation step in this order. Thereby, the desulfurized and hydrogenated hydrocarbon mixture finally obtained can be suitably used as a raw material for ethylene crackers or a gasoline base material.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples. In the following, “%” is based on weight unless otherwise specified. Moreover, the test and evaluation followed the following.

[Example 1]
(Preparation of sulfur compound-containing C5 raffinate)
C5 raffinate was introduced into a gasification tube made of stainless steel (length: 250 mm, inner diameter: 23.2 mm) heated to 190 ° C. with a liquid feed pump, and gasified. The gasified C5 raffinate is then introduced into a stainless steel pyrolysis tube (length: 250 mm, inner diameter 23.2 mm) heated to 350 ° C. to thermally decompose mainly dicyclopentadiene in the C5 raffinate. Processing was performed. The decomposition tube outlet gas was condensed with a heat exchange type cooler. The content rate of the sulfur compound in the obtained condensed liquid was 43 weight ppm in conversion of the sulfur atom. In order to perform an acceleration test of the desulfurization catalyst, the obtained condensate was converted into 1600 wt ppm ethanethiol, 1600 wt ppm dimethyl sulfide, 1600 wt ppm carbon disulfide, and 200 wt ppm in terms of sulfur atom. Thiophene was added to obtain a sulfur compound-containing C5 raffinate. In addition, about the obtained sulfur compound containing C5 raffinate, the compositional analysis by a gas chromatograph was performed. About the obtained hydrocarbon compound, the content rate is shown in Table 1.

(Catalyst reduction treatment)
To a jacketed stainless steel reaction tube (length: 250 mm, inner diameter: 23.2 mm) heated to 100 ° C., a nickel-supported catalyst (manufactured by JGC Chemical Co., Ltd., N112 catalyst, supported metal: nickel 50%, copper 2%, 20 g of chromium (2%, carrier: diatomaceous earth) was charged, and hydrogen gas was introduced at a supply rate of GHSV = 300. Subsequently, the temperature of the reaction tube was raised to 200 ° C. over 1 hour. Next, the temperature of the reaction tube was raised to 250 ° C., and the nickel supported catalyst was reduced by reacting for 4 hours while maintaining the temperature as it was.

(Desulfurization test)
The sulfur compound-containing C5 raffinate prepared above was introduced into a stainless steel vaporizing tube (length: 250 mm, inner diameter: 23.2 mm) heated to 190 ° C. with a feed pump at a supply rate of LHSV = 1.56. Gasified. Next, stainless steel filled with 20 g of the nickel-supported catalyst heated at 300 ° C. together with the gasified sulfur compound-containing C5 raffinate and hydrogen gas (supply rate: GHSV = 311) and subjected to the reduction treatment described above. The reaction tube was introduced into a reaction tube (length: 250 mm, inner diameter: 23.2 mm). At this time, the temperature in the reactor was 320 to 330 ° C., and the reaction pressure was 0.01 MPa or less. The reaction tube outlet gas was condensed with a heat exchange type cooler to obtain a condensate.

And in this example, by continuously supplying the sulfur compound-containing C5 raffinate together with hydrogen gas to a stainless steel reaction tube filled with a nickel-supported catalyst that has undergone a reduction treatment, continuous operation is performed, The obtained condensate was extracted at regular intervals, and the extracted condensate was analyzed for sulfur compounds using a gas chromatograph equipped with a chemiluminescent sulfur detector. In this example, such a test was conducted until the desulfurization rate fell below 90%. Table 2 shows the S / Ni molar ratio (ratio of the number of moles of S atoms in the desulfurized sulfur compound to the number of moles of Ni atoms contained in the nickel-supported catalyst) when the desulfurization rate falls below 90%, and The molar amount (in terms of sulfur atom) of each desulfurized sulfur compound when the desulfurization rate falls below 90% is shown.
In addition, the desulfurization rate was calculated | required from the following formula | equation.
Desulfurization rate (%) = 100 × (mol amount of sulfur atom of sulfur compound in sulfur compound-containing C5 raffinate−mol amount of sulfur atom of sulfur compound in the generated condensate) / sulfur compound in sulfur compound-containing C5 raffinate Molar amount of sulfur atom

  In this example, the composition analysis was performed using a gas chromatograph with an FID detector (manufactured by Agilent Technologies) as a measuring device, and HP-1 (60 m × 250 μm × 1.0 μm) as a capillary column. Injection volume: 1.0 μL, split ratio: 1/50, inlet temperature: 140 ° C., detector temperature: 300 ° C., carrier gas: helium, and carrier gas flow rate: 1.0 ml / min, oven temperature: 40 Heating is started at 40 ° C., held at 40 ° C. for 10 minutes, then heated to 250 ° C. at a rate of 10 ° C./min, and further heated to 280 ° C. at a rate of 20 ° C./min. I did it. And the content rate of each hydrocarbon compound was calculated | required by the area ratio from the obtained analysis result.

  In this example, the analysis of sulfur compounds was performed using HP-1 (30 m × 320 μm × 1.0 μm) with a gas chromatograph equipped with a chemiluminescent sulfur detector (manufactured by Agilent Technologies) as a measuring device and a capillary column. ), Sample injection amount: 0.2 μL, split ratio: 1/50, inlet temperature: 140 ° C., detector temperature: 800 ° C., carrier gas: helium, and carrier gas flow rate: 1.0 ml / min , Oven temperature: start heating at 40 ° C., hold at 40 ° C. for 10 minutes, then heat up to 240 ° C. at a rate of 10 ° C./min, and further up to 280 ° C. at a rate of 20 ° C./min This was done by raising the temperature. And the concentration of each sulfur compound was computed from the obtained analysis result by the absolute calibration curve method.

[Example 2]
A desulfurization test was conducted in the same manner as in Example 1 except that the conditions for the reduction treatment of the nickel-supported catalyst were changed from 250 ° C. for 4 hours to 300 ° C. for 4 hours. The results are shown in Table 2.

Example 3
A desulfurization test was performed in the same manner as in Example 1 except that the conditions for the reduction treatment of the nickel-supported catalyst were changed from 250 ° C. for 4 hours to 350 ° C. for 4 hours. The results are shown in Table 2.

Example 4
A desulfurization test was conducted in the same manner as in Example 2 except that an N102F catalyst (manufactured by JGC Chemical Co., Ltd., supported metal: 60% nickel, carrier: magnesia-silica) was used as the nickel-supported catalyst instead of the N112 catalyst. It was. The results are shown in Table 2.

[Comparative Example 1]
A desulfurization test was performed in the same manner as in Example 1 except that the conditions for the reduction treatment of the nickel-supported catalyst were changed from 250 ° C. for 4 hours to 200 ° C. for 4 hours. The results are shown in Table 2.

[Comparative Example 2]
A desulfurization test was performed in the same manner as in Example 2 except that hydrogen gas was not introduced when the desulfurization test was performed. The results are shown in Table 2.

  From Table 2, when a nickel-supported catalyst reduced at 230 to 500 ° C. was used as a desulfurization catalyst and the desulfurization reaction was performed in a reducing atmosphere (hydrogen gas atmosphere), the catalyst life was long (desulfurization). The treatment amount of the sulfur compound until the rate fell below 90% was large), and it was possible to remove various sulfur compounds well (Examples 1 to 4).

On the other hand, when a nickel-supported catalyst reduced at 200 ° C. was used, the life of the catalyst was short (the amount of sulfur compound treated until the desulfurization rate fell below 90%) was obtained (Comparative Example). 1).
In addition, when the desulfurization reaction is performed in a non-reducing atmosphere, the life of the catalyst is extremely short (desulfurization rate) even when a nickel-supported catalyst reduced at 230 to 500 ° C. is used as the desulfurization catalyst. (The treatment amount of the sulfur compound until the amount of 90% or less is extremely small) was obtained (Comparative Example 2).

Claims (3)

  Gas phase, reduction using a supported nickel-based catalyst obtained by reducing at least a part of a sulfur compound contained in a hydrocarbon mixture containing 10% by weight or more of diolefins at 230 to 500 ° C. A method for desulfurizing a hydrocarbon mixture, characterized by being removed under an atmosphere.   The method for desulfurizing a hydrocarbon mixture according to claim 1, wherein the sulfur compound is removed under conditions of a pressure of 0.3 MPa or less and a temperature of 180 to 400 ° C.   The desulfurization method according to claim 1 or 2, wherein the hydrocarbon mixture is a thermal decomposition product of naphtha.