JP2003226662A - Method for producing dimethyl ether - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing dimethyl ether (DME) enabling the conversion of a raw material containing methanol into dimethyl ether and the effective utilization of methanol contained in water separated and discharged from a distillation column. <P>SOLUTION: Dimethyl ether is produced by using an apparatus provided with an inner reaction column packed with a dimethyl ether synthesis catalyst, an outer reaction column placed outside of the inner column and packed with a methanol decomposition catalyst and a distillation column connected to the inner and the outer reaction columns. The production method comprises a step to feed a heated raw material containing methanol to the inner reaction column, a step to feed the reaction product to the distillation column and separate the product into dimethyl ether, methanol and water and a step to feed the methanol-containing water to the outer reaction column and decompose to hydrogen and carbon dioxide. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing dimethyl ether (DME).

[0002]

2. Description of the Related Art Recently, DME is an LP used for fuel, etc.
It has attracted attention as an alternative to G and is being considered for use in a wide range.

By the way, conventionally, the DME is manufactured by using the manufacturing apparatus shown in FIG. That is, in the manufacturing apparatus shown in FIG.
And a cooling chamber 103 in which a cooling fluid, for example, water circulates, is disposed on the outer periphery. The water supply channel 104 is
It is connected near the bottom of the cooling chamber 103. The vapor discharge channel 105 is connected to the upper portion of the cooling chamber 103.

The raw material supply channel 106 is the reaction tower 101.
Attached to the bottom of. The heat exchanger 107 is interposed in the raw material supply passage 106.

The DME distillation column 108 is the reaction column 101.
Is connected through a flow path 109 connected to the upper part of the reaction tower 101. The flow path 109 is the heat exchanger 1
It is cross-connected with 07. The cooler 110 is interposed in the flow path 109.

Next, a method of manufacturing the DME will be described with reference to the manufacturing apparatus shown in FIG.

First, the raw material heated to 240 to 320 ° C.,
For example, by supplying 100 volume% methanol to the reaction tower 101 through the raw material supply flow path 106, DME is synthesized in the presence of a DME synthesizing catalyst such as an alumina-based catalyst in the packing portion 102. At this time, since the DME synthesis reaction is an exothermic reaction, hot water or steam can be obtained from the steam discharge flow path 105 by supplying water to the cooling chamber 103 through the water supply flow path 104.

The reactant containing DME is supplied to the DME distillation column 108 through the channel 109. While flowing through the flow path 109, the reaction product is heat-exchanged with the raw material flowing through the raw material supply flow path 106 in the heat exchanger 107, the reaction product is cooled, and the raw material is heated. Further, the reaction product is cooled by a cooler 110 and supplied to the distillation column 108. The reaction product supplied to the distillation column 108 is separated into DME and water containing methanol to obtain DME.
Is discharged from the top of the distillation column 108 and recovered, and water containing methanol is discharged from the bottom thereof.

However, in the above-mentioned conventional DME manufacturing method, although the water discharged from the bottom of the DME distillation column 108 contains methanol, the water was discarded without being effectively utilized.

[0010]

DISCLOSURE OF THE INVENTION The present invention is capable of converting a raw material containing methanol into DME, and the methanol contained in the water separated and discharged from the distillation column is converted into hydrogen by utilizing the heat generated when the DME is converted. Which can be effectively used by decomposing it into carbon dioxide and carbon dioxide
The present invention is intended to provide a manufacturing method of.

[0011]

The method for producing DME according to the present invention comprises an inner reaction column filled with a catalyst for dimethyl ether synthesis and an outer side arranged outside the reaction column and filled with a catalyst for decomposing methanol. Using a dimethyl ether production apparatus equipped with a reaction column and a distillation column connected to these inner and outer reaction columns, in producing dimethyl ether, a raw material containing heated methanol is supplied to the inner reaction vessel. Generating a reaction product by
The method includes supplying the reaction product to the distillation column to separate it into water containing dimethyl ether and methanol, and supplying water containing the methanol to the outer reaction column to decompose it into hydrogen and carbon dioxide. It is characterized by that.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for manufacturing a DME of the present invention will be described in detail with reference to FIG.

The cylindrical inner reaction tower 1 has a packing portion 2 for a DME synthesis catalyst such as an alumina catalyst inside and a packing portion 3 for a methanol decomposition catalyst such as a copper catalyst on the outer periphery.
A ring-shaped outer reaction tower 4 having is installed.

The raw material supply flow path 5 is connected to the bottom of the inner reaction tower 1. The first and second heat exchangers 6 and 7 are
It is provided in the raw material supply passage 5.

The DME distillation column 8 is connected to the inner reaction column ₁ through a channel 9 ₁ connected to the upper part of the inner reaction column 1. The flow path 9 ₁ is cross-connected to the first heat exchanger 6. The cooler 10 is interposed in the flow path 9 ₁ . The distillation column 8, the bottom portion is connected to the outer reaction tower 24 through the channel 9 _2. Pump 11
Is provided in the flow path 9 ₂ near the distillation column 8. Further, the flow path 9 ₂ is cross-connected to the second heat exchanger 7.

The branched raw material supply flow passage 12 is branched from the raw material supply flow passage 5 and is connected to the flow passage 9 ₂ . The discharge flow passage 14 in which the cooler 13 is interposed is connected to the outer reaction tower 4.

Next, a method of manufacturing the DME will be described with reference to the manufacturing apparatus shown in FIG.

First, the raw material heated to 240 to 320 ° C.,
For example, by supplying 100% by volume of methanol to the cylindrical inner reaction tower 1 through the raw material supply flow path 5, DME is synthesized in the presence of a DME synthesizing catalyst such as an alumina catalyst in the packing part 2. . This DME synthesis reaction is
It is an exothermic reaction.

The reaction product containing DME is supplied to the DME distillation column 8 through the flow path 9 ₁ . The reaction product is
While flowing through the flow path 9 _1, is the raw material and heat exchange in the first heat exchanger 6 flows through the raw material supply passage 5, the reaction product is cooled, the raw material is heated. Further, the reaction product is cooled by a cooler 10 and supplied to the distillation column 8. The reaction product supplied to the distillation column 8 is separated into DME and water containing methanol, and DME is discharged from the upper part of the distillation column 8 and recovered.

On the other hand, water containing methanol is supplied to the annular outer reaction column 4 from the bottom of the distillation column 8 through the flow path 9 ₂ by driving the pump 11. Water containing the methanol, while flowing through the flow channel 9 _2, is a raw material and heat exchange which flows through the raw material supply passage 5 in the second heat exchanger 7, the water is heated, the raw material is cooled. The methanol-containing water supplied to the outer reaction tower 4 decomposes the methanol contained in the packing portion 3 in the presence of the methanol decomposition catalyst to generate hydrogen and carbon dioxide. The methanol decomposition reaction is an endothermic reaction, and the DME synthesis reaction is an exothermic reaction, and the heat balance during these reactions is balanced,
The heat can be effectively used.

In such a methanol decomposition reaction, when the amount of methanol at the bottom of the distillation column 8 is small, the raw material methanol is passed from the raw material supply passage 5 through the branched raw material supply passage 12 to produce water containing the methanol. It is introduced into the flow channel 9 ₂ .

The hydrogen and carbon dioxide produced in the outer reaction tower 4 are exhausted and recovered through the exhaust passage 14 in which the cooler 13 is interposed.

As described above, according to the above-described embodiment, the raw material containing methanol can be converted into DME in the inner reaction tower 1, and the methanol separated from the distillation tower 8 is divided into the annular outer reaction tower 4 around the inner reaction tower 21. Supply water containing
Hydrogen can be mainly obtained by decomposing using the heat generated in the inner reaction tower 1 (exothermic reaction heat) and the catalyst for decomposing methanol charged in the outer reaction tower 4.

Therefore, DM containing a raw material containing methanol
It can be converted to E, and the methanol contained in the water separated and discharged from the distillation column 8 can be effectively used.

Further, in the decomposition reaction of methanol, by introducing methanol as a raw material from the raw material supply flow passage 5 through the branched raw material supply flow passage 12 into the flow passage 9 ₂ through which the water containing methanol flows, the distillation is performed. Even if the amount of methanol at the bottom of the tower 8 is small, appropriate decomposition of methanol can be performed and hydrogen can be stably obtained.

Although the reaction tower filled with the catalyst for dimethyl ether synthesis is arranged inside and the reaction tower filled with the catalyst for methanol decomposition is arranged outside in the above-mentioned embodiment, these reaction towers may be arranged in reverse. Good.

[0027]

As described above in detail, according to the present invention, a raw material containing methanol can be converted into DME, and the methanol contained in the water separated and discharged from the distillation column can be converted into DME.
It is possible to provide a method for producing DME which can be effectively converted into hydrogen mainly by utilizing the heat at the time of conversion.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a manufacturing apparatus for manufacturing a DME of the present invention.

FIG. 2 is a schematic view showing a manufacturing apparatus for manufacturing a conventional DME.

[Explanation of symbols]

1 ... Inside reaction tower, 4 ... Outer reaction tower, 8 ... DME distillation column.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4D076 AA16 BB03 FA02 FA12 HA11                       JA03                 4H006 AA02 AC43 BD33 BD81 BD84                       GN05 GP01

Claims (2)

[Claims] 1. An inner reaction column filled with a catalyst for dimethyl ether synthesis, an outer reaction column arranged outside the reaction column and filled with a catalyst for decomposing methanol, and connected to these inner and outer reaction columns. In the production of dimethyl ether using a dimethyl ether production apparatus equipped with a distillation column, a step of supplying a raw material containing heated methanol to the inner reaction vessel to produce a reaction product, and the reaction product And a step of separating dimethyl ether and water containing methanol into the distillation column, and a step of supplying water containing the methanol to the outer reaction column to decompose into hydrogen and carbon dioxide, A method for producing dimethyl ether. 2. The method for producing dimethyl ether according to claim 1, wherein a desired amount of methanol is added to the water containing methanol.