JPWO2014054778A1 - Raw material oil for dehydrogenation system and dehydrogenation system - Google Patents

Abstract

A feedstock for a dehydrogenation system containing a saturated six-membered ring component, comprising at least one saturated six-membered ring component selected from the group consisting of cyclohexane, methylcyclohexane and dimethylcyclohexane in a hydrogenated state, A feedstock for a dehydrogenation system is disclosed in which the ratio of the dimer of the saturated six-membered ring component is less than 0.3% by mass based on the mass of the entire feedstock.

Description

  The present invention relates to a feedstock for a dehydrogenation system and a dehydrogenation system.

  Hydrogen is widely used in various industrial fields including the petroleum refining and chemical industries, but in recent years it has attracted attention as a future energy, and research on the use of hydrogen has been promoted mainly in fuel cells. Yes.

  However, hydrogen gas has a problem that it is difficult to store and transport as it is because it has a large volume per calorie and requires a large amount of energy for liquefaction. Therefore, in order to use a fuel cell as a mobile body such as a fuel cell vehicle or a distributed power source, a technology for efficiently transporting and storing hydrogen is required.

  The use of organic hydrides is being studied as a technology for transporting hydrogen gas in a compact manner. For example, a concept of utilizing hydrogenated aromatic compounds such as cyclohexane and decalin constituting a hydrogenation / dehydrogenation pair for hydrogen storage / transport has also been proposed.

  In order to realize a hydrogen transportation and storage system using this concept, it is essential to develop feedstock for dehydrogenation system using organic hydride that can efficiently extract hydrogen by dehydrogenation reaction of hydrogen carrier It is. Conventionally, industrially produced high-purity cyclohexane or the like has been used as a raw material oil for dehydrogenation. Patent Documents 1 and 2 describe a dehydrogenation system using a hydrogenated aromatic compound.

JP 2007-169072 A JP 2004-196638 A

  In recent years, organic hydride type hydrogen stations have attracted attention as the usefulness of hydrogen increases. In a relatively small dehydrogenation system such as this hydrogen station, it is desirable to take out hydrogen from the feedstock without using a special device and with high energy efficiency and high recovery rate.

  In order to increase the recovery efficiency of hydrogen, it is considered effective to some extent to use a highly purified hydrogenated aromatic compound.

  However, the use of highly purified hydrogenated aromatic compounds is generally economically disadvantageous. In particular, when the oil containing the aromatic compound obtained when hydrogen is recovered from the raw material oil is hydrogenated and reused as the raw material oil, it is not practical to excessively increase the purity of the hydrogenated aromatic compound. On the other hand, when a raw material oil that is not so high in purity is used, the hydrogen recovery rate tends to decrease due to long-term use.

  Then, this invention aims at suppressing the fall of a hydrogen recovery rate, without using the saturated 6-membered ring component which highly purified about the feedstock for dehydrogenation systems containing a saturated 6-membered ring component. .

  The present invention relates to a feedstock for a dehydrogenation system containing a saturated six-membered ring component. The feedstock according to the present invention contains at least one saturated six-membered ring component selected from the group consisting of cyclohexane, methylcyclohexane and dimethylcyclohexane in a hydrogenated state. Based on the total mass of the feedstock, the total proportion of the dimers of saturated six-membered ring components is less than 0.3% by mass.

  According to the raw material oil according to the present invention, it is possible to suppress a decrease in the hydrogen recovery rate without using a saturated six-membered ring component having a highly enhanced purity.

  The saturated six-membered ring component may contain methylcyclohexane. The ratio of methylcyclohexane may be 89.88% by mass or more based on the mass of the whole raw material oil.

  The feedstock according to the present invention may further contain at least one saturated five-membered ring component selected from the group consisting of methylcyclopentane and dimethylcyclopentane in the hydrogenated state. The ratio of the saturated five-membered ring component may be 0.048% by mass or more based on the mass of the entire raw material oil.

  The feedstock according to the present invention may further contain paraffin in the hydrogenated state. The ratio of paraffin may be 0.28% by mass or more based on the mass of the whole raw material oil.

  The ratio of the saturated six-membered ring component may be 94.7% by mass or more based on the mass of the whole raw material oil.

  The present invention also relates to a dehydrogenation system including a dehydrogenation reactor that dehydrogenates the above dehydrogenation system feedstock to produce hydrogen.

  According to the feed oil according to the present invention, a high hydrogen recovery rate of, for example, 90 mol% or more can be achieved. In addition, according to the present invention, there is provided a dehydrogenation system capable of stably producing hydrogen by suppressing a decrease in the recovery rate sufficiently efficiently without providing a special operating device and capital investment. Can do.

It is a conceptual diagram which shows one Embodiment of a dehydrogenation system.

  Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

  FIG. 1 is a conceptual diagram showing an embodiment of a dehydrogenation system. The dehydrogenation system shown in FIG. 1 includes a dehydrogenation reactor that dehydrogenates a hydrogenated feedstock containing a saturated six-membered ring component as an organic hydride to generate hydrogen. Using this dehydrogenation system, an organic hydride hydrogen station, a power generation system, and the like can be configured.

  A dehydrogenation catalyst is disposed in the dehydrogenation reactor. Feed oil is supplied into the dehydrogenation reactor, and hydrogen produced by dehydrogenation of the feed oil is taken out. The dehydrogenated product produced by dehydrogenation is also recovered. The dehydrogenated product contains an unsaturated six-membered ring component. Heat for the dehydrogenation reaction is supplied by circulating the heated gas through the dehydrogenation reactor. The dehydrogenation catalyst is not particularly limited, and is selected from, for example, a platinum catalyst, a palladium catalyst, and a nickel catalyst. These catalysts may be supported on a carrier such as alumina, silica and titania.

  The feedstock according to this embodiment contains a saturated six-membered ring component as a main component. Specifically, the ratio of the saturated six-membered ring component in the feed oil is usually 90% by mass or more and 99.9% by mass or less, and 94.7% by mass or more based on the total mass of the feed oil. Good.

  A saturated six-membered ring component is a compound having one or more cyclohexane rings. Specific examples of the saturated six-membered ring component that can be contained in the raw material oil include cyclohexane, methylcyclohexane, and dimethylcyclohexane. The ratio of methylcyclohexane may be 89.88% by mass or more based on the mass of the whole raw material oil.

  The ratio of paraffin in the raw material oil may be 0.28% by mass or more based on the mass of the entire raw material oil.

  In order to avoid excessive capital investment, the ratio of the saturated five-membered ring component in the hydrogenated raw material oil may be 0.048% by mass or more based on the total mass of the raw material oil. The saturated five-membered ring component may contain at least one compound selected from the group consisting of methylcyclopentane and dimethylcyclopentane.

  The ratio of the dimer of the saturated six-membered ring component in the raw material oil is preferably less than 0.3% by mass based on the total mass of the raw material oil. Moreover, 0.27 mass% or less or 0.25 mass% or less may be sufficient as the ratio of the dimer of a saturated 6-membered ring component. When the proportion of the dimer increases, the hydrogen recovery rate tends to decrease with time. The lower limit of the ratio of the dimer may be 0% by mass, but may be 0.05% by mass or more in order to avoid excessive capital investment.

  The feedstock according to this embodiment can be produced by a method including a step of hydrogenating an unsaturated six-membered ring component to produce a saturated six-membered ring component. The reaction conditions for the hydrogenation may be the conditions for treatment using a general hydrogenation apparatus. For example, the reaction temperature is preferably 200 to 380 ° C. and the hydrogen / oil ratio is 10 to 500 NL / L. As the reaction temperature increases, the proportion of the dimer of the six-membered ring component tends to increase.

  As the hydrogenation catalyst used in the hydrogenation reaction, a general catalyst having a support and an active metal supported on the support can be used. Examples of the active metal species include Pt, Pd, and Ni. Examples of the carrier include inorganic composite oxides and substances containing solid acids such as zeolite.

  After the hydrogenation reaction, if necessary, purification such as distillation can be performed to obtain a raw material oil in which the total proportion of dimers of saturated six-membered ring components is less than 0.3% by mass.

  The saturated six-membered ring component in the feedstock oil may include a component produced by hydrogenating the unsaturated six-membered ring component produced when hydrogen is recovered from the feedstock oil containing the saturated six-membered ring component. That is, the raw material oil may be a recycled product containing a component derived from a saturated six-membered ring component used once or twice or more for hydrogen recovery.

  The raw material oil as a recycled product includes, for example, a step of hydrogenating an unsaturated six-membered ring component generated when hydrogen is recovered from a raw material oil containing a saturated six-membered ring component to generate a saturated six-membered ring component. It can be manufactured by the method. It can also be used as a raw material oil for a dehydrogenation system by combining a raw material oil which is a reusable product and a separately prepared methylcyclohexane or the like.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Example 1
A general Ni catalyst used for the hydrogenation reaction was packed in a reaction tube of an atmospheric pressure flow type reaction test apparatus. Toluene was supplied to the reaction tube while heating so that the center temperature of the catalyst layer was 125 ° C. or lower. The generated gas was recovered as a liquid by cooling, and a raw material oil 1 having the composition shown in Table 1 was obtained.

  A general Pt catalyst used for the dehydrogenation reaction was filled in a reaction tube of an atmospheric pressure flow type reaction test apparatus. The raw material oil 1 was continuously supplied to the reaction tube while heating so that the center temperature of the catalyst layer was 300 to 350 ° C. The generated gas was recovered as a liquid by cooling, and analyzed by gas chromatography to measure the amount of recovered hydrogen (hydrogen recovery rate). After collecting the liquid, the flow rate of the effluent gas was measured with a gas meter. In this experiment, the initial hydrogen recovery rate (immediately after the start of the reaction) was 95.88%, and the hydrogen recovery rate from the feedstock 1 400 hours after the start of the reaction was 93.85%. The hydrogen recovery rate here is the ratio (percentage) of the mass of generated hydrogen to the mass of hydrogen that can theoretically be generated from the feedstock. The same applies to the following examples and comparative examples.

Example 2
A general Ni catalyst used for the hydrogenation reaction was packed in a reaction tube of an atmospheric pressure flow type reaction test apparatus. Toluene was supplied to the reaction tube while heating so that the center temperature of the catalyst layer was 150 ° C. or lower. The generated gas was recovered as a liquid by cooling, and a raw material oil 2 having the composition shown in Table 1 was obtained.

  When the feedstock 2 was dehydrogenated under the same conditions as in Example 1, the initial hydrogen recovery rate was 95.85%, and the hydrogen recovery rate 400 hours after the start of the reaction was 93.80%.

Example 3
A general Ni catalyst used for the hydrogenation reaction was packed in a reaction tube of an atmospheric pressure flow type reaction test apparatus. Toluene was supplied to the reaction tube while heating so that the center temperature of the catalyst layer was 175 ° C. or lower. The generated gas was recovered as a liquid by cooling, and a raw material oil 3 having the composition shown in Table 1 was obtained.

  When the feedstock 3 was dehydrogenated under the same conditions as in Example 1, the initial hydrogen recovery rate was 95.85%, and the hydrogen recovery rate 400 hours after the start of the reaction was 93.85%.

Example 4
A general Ni catalyst used for the hydrogenation reaction was packed in a reaction tube of an atmospheric pressure flow type reaction test apparatus. Toluene was supplied to the reaction tube while heating so that the center temperature of the catalyst layer was 200 ° C. or lower. The generated gas was recovered as a liquid by cooling, and a raw material oil 4 having the composition shown in Table 1 was obtained.

  When the feedstock 4 was dehydrogenated under the same conditions as in Example 1, the initial hydrogen recovery rate was 91.45%, and the hydrogen recovery rate 400 hours after the start of the reaction was 89.55%.

Example 5
A general Pt catalyst used for the hydrogenation reaction was packed in a reaction tube of a normal pressure flow type reaction test apparatus. While heating so that the center temperature of the catalyst layer was 200 ° C. or lower, a toluene mixed oil containing 0.15 mol% of a dimer was supplied to the reaction tube. The produced gas was recovered as a liquid by cooling, and a raw material oil 5 having the composition shown in Table 1 was obtained.

  When the feedstock 5 was dehydrogenated under the same conditions as in Example 1, the initial hydrogen recovery rate was 90.91%, and the hydrogen recovery rate 400 hours after the start of the reaction was 89.02%.

Comparative Example 1
A feedstock 6 having the composition shown in Table 1 was prepared. When the feedstock 6 was dehydrogenated under the same conditions as in Example 1, the initial hydrogen recovery rate was 86.17%, and the hydrogen recovery rate 400 hours after the start of the reaction was 82.58%.

Comparative Example 2
A feedstock 7 having the composition shown in Table 1 was prepared. When the feedstock 7 was dehydrogenated under the same conditions as in Example 1, the initial hydrogen recovery rate was 96.00%, and the hydrogen recovery rate 400 hours after the start of the reaction was 89.51%.

  The numerical value of the composition of each raw material oil shown in the table is mass% based on the mass of the raw material oil. In Table 1, the ratio of “saturated six-membered ring component” is the total ratio of methylcyclohexane, cyclohexane and dimethylcyclohexane. The ratio of “saturated five-membered ring component” is the total ratio of methylcyclopentane and dimethylcyclopentane.

  As shown in Table 1, in the case of the feedstock of each Example in which the proportion of the dimer of the saturated six-membered ring component is less than 0.3% by mass, a high hydrogen recovery rate exceeding 90% is achieved. The decrease in the hydrogen recovery rate was small. On the other hand, in the case of the feedstock of each comparative example in which the ratio of the dimer of the saturated six-membered ring component exceeds 0.3% by mass, the hydrogen recovery rate greatly decreased after 400 hours from the start of the reaction.

Example 6
A general Ni catalyst used for the hydrogenation reaction was packed in a reaction tube of an atmospheric pressure flow type reaction test apparatus. Toluene was supplied to the reaction tube while heating so that the center temperature of the catalyst layer was 125 ° C. or lower. The produced gas is recovered as a liquid by cooling, and a raw material oil 8 having a composition of 99.78% by mass of methylcyclohexane as a saturated six-membered ring component and 0.22% by mass of a dimer of the saturated six-membered ring component. Got.

  A Pt—Ce-based catalyst used for the dehydrogenation reaction was packed in a reaction tube of an atmospheric pressure flow type reaction test apparatus. The raw material oil 8 was continuously supplied to the reaction tube while heating so that the center temperature of the catalyst layer was 300 to 350 ° C. The supply amount at this time was eight times that of Example 1. The generated gas was recovered as a liquid by cooling and analyzed by gas chromatography to determine the methylcyclohexane conversion. After collecting the liquid, the flow rate of the effluent gas was measured with a gas meter. In this experiment, the methylcyclohexane conversion rate in the initial stage (immediately after the start of the reaction) was 37.26%, and the methylcyclohexane conversion rate from the feedstock 8 117 hours after the start of the reaction was 36.30%. The deterioration rate of the methylcyclohexane conversion rate (methylcyclohexane conversion rate / initial methylcyclohexane conversion rate × 100) was 97.42%. Since the deterioration rate of the methylcyclohexane conversion rate and the deterioration rate of the hydrogen recovery rate are synonymous, it was found that the feedstock 8 had a small decrease in the hydrogen recovery rate.

Claims (9)

In the dehydrogenation system feedstock containing a saturated six-membered ring component as the main component,
In the hydrogenated state, comprising at least one saturated six-membered ring component selected from the group consisting of cyclohexane, methylcyclohexane and dimethylcyclohexane,
A raw material oil for a dehydrogenation system, wherein the ratio of the dimer of the saturated six-membered ring component is less than 0.3% by mass based on the mass of the whole raw material oil.   The feedstock for a dehydrogenation system according to claim 1, wherein the saturated six-membered ring component comprises methylcyclohexane.   The feedstock for a dehydrogenation system according to claim 2, wherein the ratio of the methylcyclohexane is 89.88% by mass or more based on the mass of the entire feedstock.   4. The dehydrogenation system according to claim 1, further comprising at least one saturated five-membered ring component selected from the group consisting of methylcyclopentane and dimethylcyclopentane in a hydrogenated state. Raw material oil.   The raw material oil for dehydrogenation systems of Claim 4 whose ratio of the said saturated 5-membered ring component is 0.048 mass% or more on the basis of the mass of the said raw material oil whole.   The feedstock for a dehydrogenation system according to claim 4, further comprising paraffin in the hydrogenated state.   The feedstock for a dehydrogenation system according to claim 6, wherein a ratio of the paraffin is 0.28% by mass or more based on a mass of the whole feedstock.   The raw material oil for dehydrogenation systems as described in any one of Claims 1-7 whose ratio of the said saturated 6-membered ring component is 94.7 mass% or more on the basis of the mass of the said raw material oil whole.   A dehydrogenation system provided with the dehydrogenation reactor which dehydrogenates the raw material oil for dehydrogenation systems as described in any one of Claims 1-8, and produces | generates hydrogen.

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