JPH0517376A - Hydrogenation of crude naphthalenes - Google Patents

Abstract

PURPOSE:To hydrogenate a crude naphthalene to be a pretreatment for producing high-purity naphthalene in high yield. CONSTITUTION:In hydrogenating a crude naphthalene to decompose and remove impurities therewith comprising a sulfur-containing component, a nitrogen- containing component, an oxygen-containing component and a neutral component such as tetralin or olefins, etc., or to convert into compounds readily separable from naphthalene, the sulfur-containing component and the nitrogen-containing component are hydrogenated or partially hydrogenated under 0-20kg/cm<2>.G reaction pressure. Loss of naphthalene in a hydrogenating process can extremely be reduced and yield of purified naphthalene is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hydrotreating crude naphthalene compounds, and more particularly, to a insect repellent, a dye intermediate, a raw material for organic pigments, a raw material for high-performance plastics, a raw material for high-performance fibers and functionality The present invention relates to a pretreatment method for producing high-quality purified naphthalene and purified alkylnaphthalene used as raw materials for polymers, raw materials for pharmaceuticals, raw materials for surfactants, and the like.

[0002]

BACKGROUND OF THE INVENTION There are distillation methods, squeezing methods, cooling crystallization methods, pressure crystallization methods, acid / alkali treatment methods, adsorption methods, clay treatment methods, etc. as methods for purifying naphthalene compounds. A hydrotreatment is included as a pre-treatment or a post-treatment process. The purpose of this hydrogenation is to impure the separation in each of the above separation methods, for example, a component having a boiling point close to that of naphthalene,
It was to decompose and remove components forming a solid solution, and a hydrogenation treatment was adopted in which most of the sulfur-containing components were decomposed to hydrogen sulfide and most of the nitrogen-containing components were decomposed to ammonia. Specifically, the reaction pressure was 20 kg / cm ² · G or higher in all of the conventional methods. Under such conditions, the desulfurization rate and denitrification rate in the hydrotreating step are high, but at the same time, the proportion of naphthalene itself hydrogenated to tetralin is high (generally 5 to 10%), and the yield of naphthalene decreases. I also had some drawbacks.
In addition, since the tetralin produced is a neutral impurity,
There is also a problem that it cannot be removed by a simple acid / alkali treatment or adsorption method.

[0003]

Under the above-mentioned conventional hydrotreating conditions, crude naphthalene, crude alkylnaphthalene, and distillation tar fractions such as coal tar and coal liquefied oil containing these or deoxidized oil thereof ( In the present specification, when these impurities are collectively referred to as crude naphthalenes), the nuclear hydrogenation of naphthalene is unavoidable when hydrogenating or hydrocracking the impurities. Further, when trying to suppress the hydrogenation of the naphthalene nuclei, there is a problem that impurities remain and the separation efficiency in the subsequent separation step is reduced.

According to the present invention, while suppressing the hydrogenation of naphthalene nuclei, impurities, particularly olefin components, nitrogen-containing components and sulfur-containing components are selectively hydrogenated or hydrocracked, thereby performing the hydrogenation process. Alternatively, it is an object of the present invention to provide a pretreatment method for facilitating the separation of impurities in the subsequent treatment step and producing high-purity naphthalene in a high yield.

[0005]

Means for Solving the Problems The present invention, which achieves the above object, provides a sulfur-containing component, a nitrogen-containing component, an oxygen-containing component, tetralin, and olefins contained in the crude naphthalene obtained by hydrotreating the crude naphthalene. In the process of decomposing and removing impurities consisting of neutral components, etc., or converting to compounds that can be easily separated from naphthalene, the sulfur-containing components and nitrogen-containing components are partially hydrogenated at a reaction pressure of 0 to 20 kg / cm ² · G. It is characterized by

In the present invention, the above-mentioned crude naphthalene compounds are subject to hydrotreatment. As a hydrogenation catalyst, Ni, Co, W, Mo, Fe, Pt, Ru, P, which have been conventionally used, are used.
d, Rh, Si, Ge, Sn, Pb and other VIa group, VIII or IVb group metals or their oxides, one or more mixed catalysts of sulfides, or mixed catalysts thereof with alumina, silica, zeolite, It is possible to use any of the catalysts supported on a carrier of activated carbon. Preferably, a catalyst having high activity at low temperature and low pressure, for example, an alumina-supported nickel-molybdenum catalyst, an alumina-supported cobalt-molybdenum catalyst,
Examples thereof include a ruthenium catalyst supported on alumina and a platinum catalyst supported on activated carbon. The reaction pressure is 0 to 20 kg / cm ² · G, preferably 5 to 10 kg / cm ² · G, and the reaction temperature is 100 to 300.
The superficial velocity (LHSV) is 0.2 to 5 H ^-1 , and the hydrogen / naphthalene flow rate ratio (G / L) is 50 to 2000 NM ³ / M ³ .

Under the above reaction conditions, the naphthalene nucleus hydrogenation rate is 1.0% or less and the desulfurization rate is 20 to 95% (however, the hydrogenation rate of the sulfur-containing component including partial hydrogenation is 40 to 100%). ,
Denitrification rate 10 to 80% (however, hydrogenation rate of nitrogen-containing components including partial hydrogenation is 50 to 100%), deoxygenation rate 20 to 90%, olefin hydrogenation rate 80 to 100% Hydrotreating the crude naphthalene compounds.

That is, in the present invention, even if the desulfurization rate and the denitrification rate are not so high, the partial hydrogenation rate of the sulfur-containing component and the nitrogen-containing component is increased and the hydrogenation rate of the olefin is increased. is there. As a result, according to the present invention, the nuclear hydrogenation rate of naphthalene can be suppressed to 1.0% or less,
The selectivity of the heterocyclic hydrogenation reaction is higher than that of the naphthalene nuclear hydrogenation reaction. Therefore, the reaction of naphthalene itself being hydrogenated to tetralin can be significantly suppressed, and the yield of naphthalene can be improved. At the same time, it is possible to reduce the hydrogen consumption amount accompanying the nuclear hydrogenation of naphthalene. Examples of the present invention will be described below.

[0009]

【Example】

Example 1 Crude naphthalene obtained by distillation fractionation of coal tar
(95% naphthalene: composition shown in Table 1) was hydrotreated using a continuous hydrogenation equipment equipped with a fixed bed reactor.
The process flow diagram of the equipment is shown in Fig. 1. In FIG. 1, the raw material (1), crude naphthalene, is a melting tank.
After being melted in (2), it is transferred to the measuring tank (3) and supplied into the system by the circulation pump (4) and the feed pump (5). On the other hand, hydrogen (6) merges with crude naphthalene via the hydrogen pressure regulating valve (7). The crude naphthalene is heated with hydrogen in the preheater (8) and then hydrogenated in the hydrogenation reactor (9). After the hydrogenated naphthalene is cooled, it is separated as a liquid phase by a gas-liquid separator (10) and is discharged as a product (13) by a letdown valve (11) into a product receiving tank (12) at atmospheric pressure. Also, gas is a mist separator (14)
After the mist drain (15) has been removed at, it is circulated by the circulating gas compressor (16). Further, in order to keep the pressure inside the system at a constant level, excess gas (18) is released from the pressure regulating valve (17). If the hydrogen source pressure is low, the hydrogen pressure regulator (7)
You can also put a hydrogen makeup compressor in front of.

As shown in Table 2, reaction conditions are as follows: reaction pressure 6 kg / cm ² · G, reaction temperature 240, or 260 ° C., superficial velocity (LHSV) 2H ^-1 , G / L (hydrogen / naphthalene flow rate ratio). )
It was set to 200 to 800 NM ³ / M ³ . As the hydrogenation catalyst, a nickel-molybdenum catalyst supported on alumina was pre-sulfidized and used. The naphthalene hydrogenated under these conditions was qualitatively and quantitatively analyzed by gas chromatography and GC-MS. The composition of each hydrogenated naphthalene is shown in Table 3. Next, Table 4 shows the nuclear hydrogenation rate of naphthalene (that is, the naphthalene loss rate) in the hydrotreatment step, the hydrogenation rate of typical impurities, and the hydrogen consumption. In the case of benzothiophene and quinoline, the hydrogenation rate indicating how much they were hydrogenated, including partial hydrogenation, and the complete heterolysis of the heterocycle, sulfur and nitrogen are hydrogen sulfide or ammonia, respectively. Both the rate of decomposition and the rate of decomposition are shown. Here, each hydrogenation rate and decomposition rate were defined as follows. The hydrogen consumption was calculated from the hydrogen gas flow rate at the inlet and outlet and the hydrogen concentration.

Naphthalene nuclear hydrogenation rate: (tT / p) / (n + tT / p) × 10
0 Olefin hydrogenation rate: (1-i ・ p / I) × 100 Benzothiophene hydrogenation rate: (1-b ・ p / B) × 100 Benzothiophene decomposition rate: (1- (b + b _H ) p / B) × 100 Quinoline hydrogenation rate: (1-b ・ p / Q) × 100 Quinoline decomposition rate: (1- (q + q _H ) p / Q) × 100 p: Product (hydrogenated naphthalene) / raw material ( Crude naphthalene) (wt / wt) T: Tetralin content in raw material (%) t: Tetralin content in product (%) n: Naphthalene content in product (%) I: 1,2 in raw material 3- and 1,2,4-methylindene content
(%) I: Content of 1,2,3- and 1,2,4-methylindene in the product
(%) B: Benzothiophene content in the raw material (%) b: Benzothiophene content in the product (%) b _H : Dihydrobenzothiophene content in the product (%) Q: Quinoline content in the raw material ( %) Q: Quinoline content in the product (%) q _H : Tetrahydroquinoline content in the product (%) From Tables 3 and 4, the hydrogen of the present invention that appropriately controls hydrogenation or hydrogenolysis of impurities According to the chemical treatment method, the loss of naphthalene can be suppressed to 1% or less, that is, the production of tetralin, which is a neutral impurity, can be suppressed to 1% or less, and the hydrogen consumption can be suppressed.

Next, the hydrogenated naphthalene of Examples 1-1 to 1-3 thus obtained according to the present invention is further subjected to a clay treatment, a simple distillation, and a compression treatment.
In any case, purified naphthalene with a purity of 99.9% or more could be obtained. In addition, the final purified naphthalene yield was 98% or more based on the naphthalene contained in 95% naphthalene as the raw material in each case.

The refining treatment after the hydrotreating was performed by the above method as an example here, but the present invention does not define the refining method after the hydrotreating, and all the usual refining methods are used. Applicable.

Table 1

Table 2

Table 3

Table 4

Comparative Example 1 The same 95% naphthalene as in Example 1 was used in the same hydrotreating facility and the same catalyst was used to produce a reaction pressure of 25 kg / cm ² · G,
It was hydrotreated at a reaction temperature of 280 ° C. The reaction conditions, the composition of hydrogenated naphthalene, the respective hydrogenation rates, etc. are the same as in Example 1 and shown in Table 2.
To Table 3 below. The hydrogenated naphthalene of Comparative Example 1 was
When the purification treatment was carried out in the same manner as in Example 1, the purified naphthalene purity was 99.9%, but the yield was 87.5% based on naphthalene in the raw material. Example 2 95% naphthalene having the composition shown in Table 5 was hydrotreated using a batch apparatus. The reaction conditions are shown in Table 6. here,
Catalysts A and C are pre-sulfated nickel-molybdenum catalysts supported on alumina, catalyst D is pre-sulfated cobalt-molybdenum catalysts supported on alumina, catalyst E
Is a platinum catalyst supported on activated carbon, and catalyst E ′ is a catalyst E subjected to a reduction treatment. The composition of each hydrogenated naphthalene obtained is shown in Table 7, and the hydrogenation rate and decomposition rate of each component are shown in Table 8. These results indicate that the reaction conditions for appropriately suppressing the hydrogenation of impurities differ depending on the catalyst. In particular, the platinum catalyst has high selectivity for the olefin hydrogenation reaction and the quinoline hydrogenation reaction, and it can be seen that the hydrogenation of the naphthalene nucleus does not proceed so much even if the reaction temperature is high.

Table 5

[0020]

[0021]

[0022]

Comparative Example 2 The same 95% naphthalene as in Example 2 was hydrogenated using the same batch apparatus under conventional hydrorefining conditions for naphthalene compounds. As the catalyst, in addition to the catalysts A, C, and D described above, a catalyst B obtained by presulfiding a cobalt-molybdenum catalyst supported on alumina, and a catalyst obtained by presulfiding a catalyst simultaneously supporting silicon and iron together with nickel and molybdenum on alumina are used. F
5 types in total were used. The reaction conditions are shown in Table 9, the composition of the obtained hydrogenated naphthalene is shown in Table 10, and the hydrogenation rate or decomposition rate of each component is shown in Table 11.

[0024]

[0025]

[0026]

[0027]

As is clear from the comparison between Examples 1 and 2 and Comparative Examples 1 and 2, the hydrotreating method according to the present invention is one of the important steps in the naphthalene purification process. The loss of naphthalene in the process can be significantly reduced, that is, the yield of the final purified naphthalene can be improved, and the hydrogen consumption can be reduced. In addition, the hydrotreating conditions proposed by the present invention have a lower reaction pressure as compared with the conventional method, so that the power cost can be reduced. Further, when the reaction pressure is less than 10 kg / cm ² · G, the hydrotreatment equipment is not included in the high pressure gas production equipment, and the equipment cost is reduced.

As described above, the present invention can improve the economical efficiency of the naphthalene hydrotreating process. At the same time, it improves the economic efficiency of the entire naphthalene purification process.

[Brief description of drawings]

FIG. 1 is a process drawing showing an embodiment of the present invention. 1 Crude Naphthalenes 2 Melting Tank 6 Hydrogen 8 Preheater 9 Hydrogenation Reactor 13 Hydrogenated Naphthalene

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location // C07B 61/00 300 (72) Inventor Kenichi Nagata 1 Yawata Kaigan Dori, Ichihara, Chiba Mitsui Engineering & Shipbuilding Chiba Plant (72) Inventor Koichi Kono 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) In-house Yasuhiro Suda 4-1-1, Hirano-cho, Chuo-ku, Osaka-shi, Osaka No. 2 in Osaka Gas Co., Ltd. (72) Inventor Mitsuaki Yamada 4 1-2 Hirano-cho, Chuo-ku, Osaka City, Osaka Prefecture Osaka Gas Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. An impurity comprising hydrogenated crude naphthalene, which comprises sulfur-containing components, nitrogen-containing components, oxygen-containing components and neutral components such as tetralin and oleins contained in the crude naphthalene. Reaction pressure 0 to 20 kg / cm ² · G when decomposing and removing or converting to a compound that can be easily separated from naphthalene
1. A method for hydrotreating crude naphthalene compounds, which comprises hydrogenating or partially hydrogenating the sulfur-containing component and the nitrogen-containing component.