JP4043248B2 - Method for producing dimethyl ether - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing dimethyl ether (DME).
[0002]
[Prior art]
Recently, DME has attracted attention as an alternative to LPG used for fuels, and its use in a wide range is being studied.
[0003]
Conventionally, DME is manufactured using a manufacturing apparatus shown in FIG. That is, in the manufacturing apparatus shown in FIG. 2, the reaction tower 101 has a catalyst filling portion 102 inside, and a cooling chamber 103 in which a cooling fluid, for example, water circulates, is arranged around the outside. The water supply channel 104 is connected near the bottom of the cooling chamber 103. The vapor discharge channel 105 is connected to the upper part of the cooling chamber 103.
[0004]
The raw material supply channel 106 is connected to the bottom of the reaction tower 101. The heat exchanger 107 is interposed in the raw material supply channel 106.
[0005]
The DME distillation column 108 is connected to the reaction column 101 through a flow path 109 connected to the upper part of the reaction column 101. The flow path 109 is cross-connected to the heat exchanger 107. The cooler 110 is interposed in the flow path 109.
[0006]
Next, a method for manufacturing DME will be described with reference to the manufacturing apparatus shown in FIG.
[0007]
First, a raw material heated to 240 to 320 ° C., for example, 100% by volume of methanol is supplied to the reaction tower 101 through the raw material supply channel 106, so that in the presence of a DME synthesis catalyst such as an alumina catalyst in the packed portion 102. DME is synthesized by At this time, since the synthesis reaction of DME is an exothermic reaction, hot water and steam can be obtained from the steam discharge channel 105 by supplying water to the cooling chamber 103 through the water supply channel 104.
[0008]
The reactant containing DME is supplied to the DME distillation column 108 through the channel 109. While the reaction product flows through the flow path 109, the heat exchanger 107 exchanges heat with the raw material flowing through the raw material supply flow path 106, 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. The DME is discharged from the top of the distillation column 108 and recovered, and the water containing methanol is discharged from the bottom. .
[0009]
However, in the conventional method for producing DME, the water discharged from the bottom of the DME distillation column 108 contains methanol, but the methanol is discarded without being effectively used.
[0010]
[Problems to be solved by the invention]
The present invention can convert a methanol-containing raw material into DME, and decomposes methanol contained in water separated and discharged from a distillation column into hydrogen and carbon dioxide by using heat generated during the conversion of the DME. It is an object of the present invention to provide a method for producing DME that can effectively utilize the above.
[0011]
[Means for Solving the Problems]
The method for producing DME according to the present invention includes an inner reaction column filled with a catalyst for synthesizing dimethyl ether, an outer reaction column disposed outside the reaction column and filled with a catalyst for methanol decomposition, and an inner side and an outer side thereof. In producing dimethyl ether using a dimethyl ether production apparatus equipped with a distillation column connected to the reaction tower of
Supplying a raw material containing methanol heated to the inner reaction vessel to produce a reaction product;
Supplying the reaction product to the distillation column and separating it into water containing dimethyl ether and methanol;
Supplying the methanol-containing water to the outer reaction tower and decomposing it into hydrogen and carbon dioxide.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the method for producing DME of the present invention will be described in detail with reference to FIG.
[0013]
The cylindrical inner reaction tower 1 has a packed portion 2 of a DME synthesis catalyst such as an alumina catalyst inside, and an annular shape having a packed portion 3 of a methanol decomposition catalyst such as a copper catalyst on the outer periphery. An outer reaction column 4 is provided.
[0014]
The raw material supply channel 5 is connected to the bottom of the inner reaction tower 1. The first and second heat exchangers 6 and 7 are interposed in the raw material supply channel 5.
[0015]
The DME distillation column 8 is connected to the inner reaction column ₁ through a flow path 91 connected to the upper part of the inner reaction column 1. The channel 9 ₁ is cross-connected to the first heat exchanger 6. 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 of the distillation column 8 neighbors. Further, the flow channel 9 ₂ are cross-coupled to the second heat exchanger 7.
[0016]
Branch feed supply channel 12 is branched from the feed supply channel 5 is connected to the flow channel 9 _2. The discharge flow path 14 in which the cooler 13 is interposed is connected to the outer reaction tower 4.
[0017]
Next, a method for manufacturing DME will be described with reference to the manufacturing apparatus shown in FIG.
[0018]
First, a raw material heated to 240 to 320 ° C., for example, 100% by volume of methanol is supplied to the cylindrical inner reaction tower 1 through the raw material supply flow path 5 to synthesize DME like an alumina catalyst in the packed portion 2. DME is synthesized in the presence of an industrial catalyst. This DME synthesis reaction is an exothermic reaction.
[0019]
Reaction products containing DME are supplied to the DME distillation column 8 through the channel 9 _1. The reaction product, 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 the DME is discharged from the upper portion of the distillation column 8 and collected.
[0020]
Meanwhile, the water containing methanol is supplied to the outer reactor 4 from a bottom portion of the distillation column 8 by driving through the passage 9 ₂ annular 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 is decomposed in the presence of the methanol decomposition catalyst in the packed portion 3 to generate hydrogen and carbon dioxide. The methanol decomposition reaction is an endothermic reaction, and the synthesis reaction of the DME is an exothermic reaction, and the heat balance during these reactions is balanced, so that heat can be used effectively.
[0021]
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 flows from the raw material supply channel 5 through the branched raw material supply channel 12 and the water containing the methanol flows. introduced into the road 9 _2.
[0022]
Hydrogen and carbon dioxide produced in the outer reaction tower 4 are exhausted and recovered through a discharge passage 14 in which a cooler 13 is interposed.
[0023]
As described above, according to the above-described embodiment, the raw material containing methanol can be converted into DME by the inner reaction tower 1, and the water containing methanol separated from the distillation tower 8 by the annular outer reaction tower 4 around the inner reaction tower 21. Is mainly obtained by decomposing using the heat generated in the inner reaction tower 1 (exothermic reaction heat) and the methanol decomposition catalyst packed in the outer reaction tower 4.
[0024]
Therefore, the raw material containing methanol can be converted into DME, and the methanol contained in the water separated and discharged from the distillation column 8 can be used effectively.
[0025]
Further, by water containing the methanol and methanol as a raw material in the decomposition reaction of the methanol through the branch feed supply channel 12 from the raw material supply passage 5 is introduced into the flow path 9 ₂ flowing, the distillation column 8 bottom Even when the amount of methanol is small, appropriate methanol can be decomposed and hydrogen can be stably obtained.
[0026]
In the above-described embodiment, the reaction tower filled with the catalyst for synthesizing dimethyl ether is arranged on the inner side and the reaction tower filled with the catalyst for methanol decomposition is arranged on the outer side. However, these reaction towers may be arranged in reverse.
[0027]
【The invention's effect】
As described above in detail, according to the present invention, the methanol-containing raw material can be converted into DME, and the methanol contained in the water separated and discharged from the distillation tower is mainly hydrogenated by utilizing the heat at the time of DME conversion. Thus, it is possible to provide a method for producing DME that can be effectively used after being converted into the above.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a production apparatus for producing DME of the present invention.
FIG. 2 is a schematic view showing a manufacturing apparatus for manufacturing a conventional DME.
[Explanation of symbols]
1 ... Inner reaction tower,
4 ... Outer reaction tower,
8: DME distillation column.

Claims (2)

An inner reaction column filled with a catalyst for synthesizing dimethyl ether, an outer reaction column arranged outside the reaction column and filled with a catalyst for methanol decomposition, and a distillation column connected to the inner and outer reaction columns. In producing dimethyl ether using a dimethyl ether production apparatus equipped with
Supplying a raw material containing methanol heated to the inner reaction vessel to produce a reaction product;
Supplying the reaction product to the distillation column and separating it into water containing dimethyl ether and methanol;
And supplying the water containing methanol to the outer reaction tower to decompose it into hydrogen and carbon dioxide. The method for producing dimethyl ether according to claim 1, wherein a desired amount of methanol is added to the water containing methanol.

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