JP2012254951A - Method and apparatus for producing 2-3c olefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing lower olefins at low cost and in high yield.SOLUTION: This production method of 2-3C olefins includes: a first step of bringing a raw material selected from the group consisting of 1-2C hydrocarbons and 1-2C oxygenates into contact with a solid acid catalyst; and a second step of bringing the product obtained in the first step into contact with a solid basic catalyst.

Description

  The present invention relates to a process for converting hydrocarbons or oxygenates to lower olefins using a solid acid catalyst and a solid base catalyst.

  Propylene is used in large quantities as a raw material for the synthesis of acrolein, acrylonitrile, isopropyl alcohol, acetone, glycerin, cumene, propylene oxide, allyl alcohol, and the like. In addition, polypropylene obtained by polymerizing propylene is used in a wide range of fields such as building materials and food containers.

Many methods for producing propylene have been conventionally known, and a method for producing propylene from ethanol, ethylene or the like using a catalyst has been reported. For example, Patent Document 1 discloses a method for converting hydrocarbons into olefins using a solid acid catalyst and an aluminum atom-containing treatment agent. Patent Document 2 discloses a method for reactivating an deactivated catalyst without stopping the operation of a fixed bed in a method for producing an olefin polymer using a solid acid catalyst. Patent Document 3 discloses a method for separating and reusing a product having a specific carbon number from a product produced by contacting methanol or dimethyl ether with a catalyst. In Patent Document 4, C _3-8 alkane is oxidized in an oxygen atmosphere to generate a mixed gas containing carbon dioxide, water vapor, and unreacted alkane, and the mixed gas is brought into contact with a steam cracking catalyst to produce C _3. A method for producing _-8 alkenes is disclosed.

JP 2006-219560 A JP 2001-213904 A JP 2008-81438 A JP 2009-67808 A

  Many methods for producing a lower olefin by a catalytic cracking reaction are known, but the production efficiency of the lower olefin is not yet sufficient. For example, in the method of Patent Document 3, the yield of the target product can be improved by recycling the by-product, but since a by-product separation device is required, the manufacturing cost increases. Moreover, in the method of patent document 4, in order to perform several reaction from which reaction temperature differs, several reactors are needed and manufacturing cost rises.

  Therefore, an object of the present invention is to provide a method capable of producing a lower olefin at a low cost and in a high yield.

  As a result of intensive studies by the present inventors, it has been found that the above-mentioned problems can be solved by using a combination of a solid acid catalyst and a solid base catalyst.

That is, the present invention includes the following.
(1) a first step in which a raw material selected from the group consisting of C _1-2 hydrocarbon and C _1-2 oxygenate is brought into contact with a solid acid catalyst; and the product obtained in the first step is converted into a solid base catalyst. A second step of contacting the
The manufacturing method of _C2-3 olefin containing this.
(2) The method according to (1), which does not include a product separation and purification step between the first step and the second step.
(3) The method according to (1) or (2), wherein the solid acid catalyst is an aluminosilicate.
(4) The method according to any one of (1) to (3), wherein the solid base catalyst is an oxide, hydroxide, carbonate, or phosphate of an alkali metal or alkaline earth metal.
(5) The method according to any one of (1) to (4), wherein the raw material is ethanol.
(6) a first reactor comprising a solid acid catalyst; and a second reactor comprising a solid base catalyst connected to the first reactor;
An apparatus for producing C _2-3 olefins.
(7) A C _2-3 olefin production apparatus having a reaction furnace comprising a solid acid catalyst disposed on the upstream side and a solid base catalyst disposed on the downstream side.

  According to the present invention, a lower olefin can be produced at a low cost and in a high yield.

The ethanol catalytic decomposition activity evaluation in an Example and a comparative example is shown.

Hereinafter, the present invention will be described in detail.
The present invention provides a first step in which a raw material selected from the group consisting of C _1-2 hydrocarbons and C _1-2 oxygenates is brought into contact with a solid acid catalyst; and the product obtained in the first step is converted into a solid base. the second step of contacting the catalyst; including a process for the preparation of C _2-3 olefins.

  In the first step, a mixture containing compounds having various carbon numbers is generated by the reaction between the raw material and the solid acid catalyst, so that the lower olefin cannot be obtained in a high yield. Therefore, by reacting the mixture obtained in the first step with the solid base catalyst in the second step, the compound having a large number of carbon atoms in the mixture is cracked, and the content of the lower olefin can be increased. Moreover, since it is not necessary to separate a by-product between the first step and the second step, the first step and the second step can be performed continuously. This makes it possible to produce a lower olefin at a low cost.

  The solid acid catalyst is a solid catalyst that functions as a proton donor or an electron acceptor. For example, silica alumina, a solid acid obtained by attaching a normal acid to a carrier (for example, silica gel or alumina with sulfuric acid or phosphoric acid). Etc.), aluminum oxide, vanadium oxide, and the like. Although it does not specifically limit, it is preferable to use a zeolite, especially an aluminosilicate or a silicoaluminophosphate as a solid acid catalyst.

  Examples of the aluminosilicate include MFI type zeolite, MEL type zeolite, FER type zeolite, MOR type zeolite, CHA type zeolite, and TON type zeolite. Although not particularly limited, it is preferable to use MFI type zeolite, and it is particularly preferable to use ZSM-5 type zeolite.

The ratio of Si and Al in the aluminosilicate is not particularly limited, but from the viewpoint of maintaining the activity of the catalyst, the SiO ₂ / Al ₂ O ₃ (molar ratio) is preferably 20 to 1000, preferably 30 to 400 It is particularly preferred. SiO ₂ / Al ₂ O ₃ (molar ratio) can be measured using a known method. For example, the method of melt | dissolving an aluminosilicate in alkaline aqueous solution, and analyzing by plasma emission spectrometry can be mentioned.

  Examples of the silicoaluminophosphate include SAPO-5, SAPO-11, SAPO-14, SAPO-17, SAPO-18, SAPO-34, SAPO-39, and SAPO-42. Although not particularly limited, it is preferable to use a silicoaluminophosphate having a pore inlet defined by an oxygen 8-membered ring, more preferably a chabasite-type silicoaluminophosphate, It is particularly preferred to use SAPO-34.

  The aluminosilicate and silicoaluminophosphate may contain any metal atom in addition to Si and Al. For example, sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), silver (Ag ), Lead (Pb), or the like.

  A solid base catalyst is a substance whose surface is basic in the solid state, such as oxides, hydroxides, carbonates, phosphates of alkali metals and alkaline earth metals, and mixed oxidations containing them. Things can be mentioned. More specifically, magnesium oxide, calcium oxide, magnesium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, hydroxyapatite, hydrotalcite and the like can be mentioned.

In the present invention, C _1-2 hydrocarbon or C _1-2 oxygenate is used as a raw material. Examples of the C _1-2 hydrocarbon include methane, ethane, ethylene, and alkylene. Examples of the C _1-2 oxygenate include methanol, ethanol, dimethyl ether, formaldehyde, formic acid, acetic acid and the like. Although it does not specifically limit, it is preferable to use ethanol as a raw material.

The raw material may be supplied as it is or may be supplied as a mixed gas with a dilution gas. The diluent gas is not particularly limited as long as it exists in a gaseous state under conditions where the raw material exists in a gaseous state and does not adversely affect the conversion of the raw material into C _2-3 olefin. For example, an inert gas such as nitrogen or argon can be used. In order to use industrially, it is preferable to use a raw material in high concentration. For example, the raw material concentration (molar ratio) is preferably 50% or more, more preferably 70% or more, and particularly preferably 90% or more.

Examples of the _C2-3 olefin produced according to the present invention include ethylene and propylene.

  Although reaction temperature will not be specifically limited if the raw material and the product in a 1st process are efficiently and selectively converted into a lower olefin, For example, 300-700 degreeC is preferable and 400-600 degreeC is especially preferable. The reaction temperature in the first step and the second step may be the same or different. From the viewpoint of production cost, it is preferable to perform the first step and the second step at the same reaction temperature.

  The conversion from the raw material to the lower olefin can be confirmed by analyzing the produced gas by gas chromatography.

The present invention also relates to an apparatus for producing _C2-3 olefins. The production apparatus of the present invention includes a first reaction furnace provided with a solid acid catalyst; and a second reaction furnace provided with a solid base catalyst connected to the first reaction furnace. The raw material is first supplied to the first reactor, and the product generated in the first reactor is transferred to the second reactor.

  The production apparatus of the present invention may have a single reactor equipped with a solid acid catalyst and a solid base catalyst. In this case, by arranging the solid acid catalyst on the upstream side of the reaction furnace and the solid base catalyst on the downstream side, the raw material can be reacted first with the solid acid catalyst and subsequently with the solid base catalyst. . Equipment costs can be reduced by using a single reactor. In addition, since the energy for maintaining the reaction temperature is less than that in the case of using a plurality of reaction furnaces, the manufacturing cost can be reduced.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example and a comparative example, the technical scope of this invention is not limited to this.

Example 1
Solid acid catalyst:
0.5 g of NH ₄ —ZSM-5 type zeolite (manufactured by Tosoh Corporation, SiO ₂ / Al ₂ O ₃ molar ratio 39) was used for activity evaluation.

Solid base catalyst:
20 g of magnesium chloride hexahydrate was dissolved in 100 ml of ion exchange water, and 40 ml of 10% aqueous ammonia was added dropwise with stirring. The resulting precipitate was filtered off, dried, and calcined at 600 ° C. for 1 hour in an air atmosphere to obtain a white powder of magnesium oxide. 1 g of magnesium oxide was used for activity evaluation.

Activity evaluation:
The ethanol catalytic cracking reaction was measured using a fixed bed flow reactor. NH ₄ —ZSM-5 type zeolite was charged on the upstream side of the reaction furnace, and magnesium oxide was charged on the downstream side. In 1 minute, 278 ml of vaporized ethanol + nitrogen mixed gas (EtOH: N ₂ = 90: 10) was brought into contact with the catalyst at 500 ° C. The produced gas was analyzed by gas chromatography.

The carbon yield was calculated by the following formula.
Carbon yield (%) = [number of moles of product gas × number of carbons per mole of each component / (number of moles of supplied ethanol × 2)] × 100

Example 2
The same operation as in Example 1 was performed except that 1 g of magnesium oxide (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the solid base catalyst.

Example 3
The same operation as in Example 1 was performed except that 1 g of hydroxyapatite (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the solid base catalyst.

Example 4
The same operation as in Example 1 was performed except that 1 g of white powder obtained by firing calcium acetate monohydrate (manufactured by Nacalai Tesque) at 600 ° C. for 1 hour in an air atmosphere was used as the solid base catalyst. .

Comparative Example 1
The same operation as in Example 1 was performed except that the solid base catalyst was not used.
The ethanol catalytic cracking activity evaluation in Examples 1 to 4 and Comparative Example 1 is shown in Table 1 and FIG.

  By using a solid base catalyst in combination, the production amount of olefins having 4 or more carbon atoms was reduced, and the production amounts of ethylene and propylene were improved.

Claims (7)

A first step in which a raw material selected from the group consisting of C _1-2 hydrocarbons and C _1-2 oxygenates is contacted with a solid acid catalyst; and the product obtained in the first step is contacted with a solid base catalyst. Second step;
The manufacturing method of _C2-3 olefin containing this.   The method according to claim 1, which does not include a product separation and purification step between the first step and the second step.   The process according to claim 1 or 2, wherein the solid acid catalyst is an aluminosilicate.   The method according to any one of claims 1 to 3, wherein the solid base catalyst is an alkali metal or alkaline earth metal oxide, hydroxide, carbonate, or phosphate.   The method according to any one of claims 1 to 4, wherein the raw material is ethanol. A first reactor comprising a solid acid catalyst; and a second reactor comprising a solid base catalyst connected to the first reactor;
An apparatus for producing C _2-3 olefins. An apparatus for producing _C2-3 olefin, comprising a reaction furnace comprising a solid acid catalyst arranged on the upstream side and a solid base catalyst arranged on the downstream side.

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