JP3523763B2 - Reduction activation method and reduction treatment apparatus for dimethyl ether synthesis catalyst - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pretreatment method for a catalyst used when dimethyl ether is synthesized from a synthesis gas containing hydrogen and carbon monoxide as main raw materials.

[0002]

BACKGROUND OF THE INVENTION Dimethyl ether has low toxicity and is stable, and is used as a propellant (propellant) instead of CFC, an intermediate raw material for synthetic gasoline, an alternative fuel for LPG and a fuel for diesel engines.

As a technique for directly synthesizing dimethyl ether (DME) from a synthesis gas containing hydrogen and carbon monoxide as main raw materials, a technique for allowing the synthesis gas to pass through a fixed bed catalyst layer and reacting it has been developed. JP-A-2-280
836, Japanese Patent Laid-Open No. 3-8466).

However, the DME synthesis reaction is a strong exothermic reaction. Therefore, the catalyst layer of the DME synthesis reaction easily causes local heating, and deactivation of the catalyst becomes a problem. Therefore, the present inventor prevents local heating of the catalyst layer by passing the synthesis gas through the slurry bed reactor in which the catalyst fine particles are suspended in the high boiling point medium oil, and thus the high yield is achieved. DM
A DME liquid phase synthesis reaction technique capable of synthesizing E has been developed (for example, JP-A-3-181435 and JP-A-5-810069).

The catalyst used in the DME liquid phase synthesis reaction is, for example, one kind or a mixture of two or more kinds of copper-zinc or copper-zinc-aluminum type fine powder catalysts. In the stage where these fine powder catalysts are manufactured by adjusting the component composition, each catalyst metal component is a mixture of fine particles in the form of stable oxide. In order to exert the function as a catalyst in the DME synthesis reaction, it is necessary to reduce and activate the mixed oxide particles in advance (pre-reduction activation). Immediately before starting the DME synthesis reaction operation, the method is carried out in a slurry bed reactor in which catalyst fine particles composed of the above mixed oxide having a predetermined component composition are suspended in a predetermined high boiling point medium oil. It is preferable that the catalytic metal component in the form of a stable metal oxide is reductively activated by gradually raising the temperature under a high pressure while circulating a reducing gas.

In the reduction activation of the catalyst, in order to avoid deactivation of the catalyst performance due to overreduction of the catalyst metal or sintering of the metal component, the temperature rising rate, the ultimate temperature, the
It is necessary to optimize the reduction holding time at the ultimate temperature. Furthermore, it is important to properly adjust the reducing performance of the reducing gas used for the reducing treatment to be mild. For example, in the above-mentioned publication, JP-A-3-181435, and JP-A-5-810069, the reduction activation of the DME synthesis catalyst in such a slurry bed reactor is as follows.
In order to adjust the reducing performance of the reducing gas, hydrogen which is a reducing gas or a mixed gas of carbon monoxide and hydrogen is added in an amount of 10 to 4
About 0 vol.% And nitrogen, which is an inert gas, at 90 to 60 vo
It discloses using a reducing gas mixed with l.% (hereinafter referred to as "prior art").

FIG. 3 is a flow sheet showing an example of a conventional manufacturing apparatus used for directly synthesizing dimethyl ether from the above-mentioned synthesis gas containing carbon monoxide and hydrogen as main components. This production apparatus comprises a reactor R1 for dimethyl ether synthesis, and a gas reformer or shift reactor R for converting the molar concentration ratio of CO and H ₂ of a reaction raw material gas to be supplied.
2, a methanol / water separator S1, an unreacted gas separator S2, and a CO ₂ separator S3.

Hydrocarbon as a raw material gas, for example, natural gas 14 'and steam 15' is supplied to the reformer R2. In the reformer R2, the natural gas 14 'is reformed (reformed) with the steam 15' to prepare the makeup gas 1 '. Recycle gas 7'having unreacted carbon monoxide and hydrogen as main components is mixed with makeup gas 1'in gas mixer M1 to prepare dimethyl ether synthesis gas 2b '.

The synthesis gas 2b 'is supplied to the reactor R1. The reaction product gas 3 ′ flows out from the reactor R1,
Enter the methanol / water separator S1. Here, the reaction product gas 5 ′ from which methanol and water 4 ′ have been separated enters the unreacted gas separator S2. Here, the unreacted gas (main components: CO and H ₂ ) is separated and becomes the recycled gas 7 ′. The DME and CO ₂ 6 ′ from which the unreacted gas has been separated enter the CO ₂ separator S 3 where CO ₂ is separated and DME is recovered. The recycle gas 7'is appropriately purged to the purge line 10 in the middle of the recycle gas line 7 ',
The remaining recycle gas 7'is mixed with the makeup gas 1'through the recycle gas line 7 and supplied to the reactor R1 as the synthesis gas 2'as described above. As described above, in the conventional one-step method of DME synthesis, unreacted CO and H ₂ are recycled to the reactor R1 to improve the utilization efficiency of the raw material gas. In addition, although methanol is recovered and used, carbon dioxide is usually discarded.

In the conventional dimethyl ether producing apparatus as described above, in order to reduce and activate the catalyst in the slurry bed reactor, hydrogen or a mixed gas of carbon monoxide and hydrogen is used as a reducing agent such as nitrogen. When a reducing gas mixed with an inert gas is prepared, it is necessary to establish a system for obtaining the inert gas and newly provide a supply process for the dimethyl ether synthesis process.

[0011]

In a commercial scale plant of dimethyl ether, a large amount of catalyst is used, and at the same time, a large amount of reducing gas is used for the reduction treatment of this catalyst. Heretofore, the acquisition of this reducing gas and the reduction treatment system for the deactivated catalyst have not been developed. By the way, D
Since the ME synthesis raw material is a mixed gas containing hydrogen and carbon monoxide as the main components, the DME synthesis raw material itself may be used as the reducing gas necessary for the reduction activation treatment of the catalyst. No dimethyl ether synthesis process has been developed. Further, it is necessary to obtain a large amount of an inert gas such as nitrogen from outside the plant for adjusting the reducing performance of the reducing gas to be mild.

Furthermore, the reaction for directly synthesizing DME from a synthesis gas containing hydrogen and carbon monoxide as main raw materials is generally a high pressure reaction carried out under a reaction pressure of 30 to 50 kg / cm ² G or more. Is. Therefore, when the synthetic catalyst gradually loses its activity and becomes less than a certain performance, it is necessary to interrupt the operation, cool the reactor, and then reduce the pressure to replace the catalyst.

In any case, the DME is operated during plant operation.
In order to carry out the reduction treatment of a new catalyst and the replacement of the catalyst after deactivating the synthetic catalyst, the plant operation was stopped, the reactor was cooled, the pressure was lowered, and the deactivated old catalyst slurry was extracted from the reactor. After charging the catalyst slurry before reduction into the reactor, the pressure was increased to about 10 Kg / cm ² G, the temperature was maintained at a predetermined temperature for a certain period of time, the reduction treatment was performed, and then 30 to 50 Kg / cm ² G or more. It is necessary to increase the pressure to the DME synthesis reaction condition of (3) and start the DME synthesis reaction.

The object of the present invention is to solve the above-mentioned problems and to carry out a reduction activation treatment of a catalyst inexpensively and stably when synthesizing dimethyl ether using hydrogen and carbon monoxide as main raw materials in a slurry bed type reactor or the like. To provide a method that can be done.

[0015]

From the above-mentioned viewpoint, the present inventor has earnestly studied to develop a pretreatment method for a dimethyl ether synthesis catalyst. At that time, the present inventor is not limited to using an inert gas such as nitrogen for mildening the reducing gas for the reducing activation treatment of the catalyst, and is a gas generated in the process in the dimethyl ether production plant. Considered to use.

As a result, it has been found that carbon dioxide, which is an oxidizing gas, can be used in place of the inert gas to exert its action in order to make the reducing performance of the reducing gas mild. We focused on using carbon dioxide generated in the dimethyl ether synthesis process.

From a synthesis gas containing hydrogen and carbon monoxide,
The reaction in the case of directly synthesizing dimethyl ether is by-produced with the following (1), (2) and (3) methanol synthesis, dimethyl ether synthesis produced by dehydration reaction from synthesized methanol, and dimethyl ether synthesis. Three types of reactions in which water and carbon monoxide react to generate hydrogen are represented as simultaneously progressing in one reactor. When the reactions (1) to (3) are summarized, the reaction (4) is Represented.

CO + 2H ₂ → CH ₃ OH ---------- (1) 2CH ₃ OH → CH ₃ OCH ₃ + H ₂ O ---------- (2) H ₂ O + CO → H ₂ + CO ₂ ---------- (3) 3CO + 3H ₂ → CH ₃ OCH ₃ + CO ₂ ---------- (4) However, the above reactions (1) to (3) Is an equilibrium reaction controlled by temperature and pressure, and thus the above three reactions do not proceed 100% in the actual synthetic process. Therefore, reaction (4), which is a summary of the above three reactions, is also 100%.
Does not progress. Therefore, as shown in the reaction (4), 100% of the raw material H ₂ and CO are not converted and the gas at the outlet of the reactor always contains unreacted H ₂ and CO. Usually, the unreacted H ₂ and CO are not discarded, and after being separated from other products, they are recycled to the dimethyl ether synthesis reactor and effectively used for use as a part of the raw material gas. However, according to the research results of the present inventor, in the recycled gas, for example, CO
₂ is mixed in about 5 to 20 vol.%.

Such mixing of carbon dioxide in the recycled gas lowers the CO conversion rate in the synthesis gas. Therefore, the CO ₂ concentration in the synthesis gas is suppressed to a predetermined value or less by purging the recycled gas at about 5 to 50 vol.%. It was noted that the above-mentioned recycled gas purged outside the system of the dimethyl ether synthesis process can be used as a reducing gas for the reduction activation treatment of the catalyst.

[0020] In this invention was made based on the above finding
And the dimethyl ether according to the invention of claim 1.
The reductive activation method of a tellurium synthesis catalyst is a reductive activation method of a catalyst used when synthesizing dimethyl ether by reacting a synthesis gas containing carbon monoxide and hydrogen with a catalyst , and a dimethyl ether synthesis reactor. Reactions emitted from
The recycle gas containing unreacted carbon monoxide and hydrogen separated from the gas is used for the dimethyl ether synthesis reaction.
The catalyst is characterized in that it is used as a reducing agent in the reduction activation treatment . Claim 2
Method for reducing activation of dimethyl ether synthesis catalyst according to invention
In the invention according to claim 1, the recycled gas is
The catalyst used for the dimethyl ether synthesis reaction is subjected to reduction activation treatment.
When used as a reducing agent when
The gas separated in the process after separation of the recycled gas
Characterized by adding a gas whose main component is carbon oxide
It is something. The dimethyl ether according to the invention of claim 3
The reduction treatment device for ether synthesis catalysts contains carbon monoxide and hydrogen.
Dimethyl ether synthesis reaction using catalyst containing synthesis gas
The reaction gas discharged from the synthesis reactor.
A dime for circulating the separated unreacted gas to the synthesis reactor.
Attached to the chill ether synthesizer and used for the synthesis reaction
A catalyst reduction treatment device for reducing activation of the catalyst.
A reduction treatment reaction tower for treatment is provided, and this reduction treatment reaction is carried out.
Connect the catalyst supply line to the tower and the synthesis reactor.
A gas line branched from the recycled gas line,
A line for sending the reduced catalyst to the synthesis reactor
Connected and before during operation of the dimethyl ether synthesizer
Enables reduction of catalysts used in synthetic reactions
It is characterized by being configured.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. [First Embodiment] FIG. 1 shows a flow sheet of an example of a dimethyl ether production apparatus for carrying out the method of the present invention.
This production equipment consists of a reformer R2 for producing make-up gas, a reactor R1 for synthesizing DME, methanol /
It comprises a water separator S1, an unreacted gas separator S2, and a CO ₂ separator S3. This manufacturing apparatus is different from the flow sheet of the conventional manufacturing apparatus shown in FIG. 3 in the following two points.

In the conventional apparatus, the recycled gas 7'separated from the reaction product gas 5'in the unreacted gas separator S2 is mixed with the makeup gas 1'in the gas mixer M1 through the recycled gas line 7. Being Syngas 2
It becomes b ′ and is supplied to the DME synthesis reactor R1.
On the other hand, in the device of the present invention, in addition to the conventional device,
After the recycled gas 7 ′ leaves the unreacted gas separator S2,
Gas switching device C1, C2 and then C3,
Recycle gas line 7a, reducing gas line 13,
Then, a step of passing through the line 2a and becoming the catalyst reducing gas 13a 'and being supplied to the DME reactor R1 is added. However, the recycle gas 7a ′ between the gas switchers C1 and C2 is added with a predetermined amount of recycle CO ₂ 8a ′ if necessary in the gas mixer M2, and is a catalyst reducing gas having a predetermined CO ₂ concentration. 13a '. The recycled gas 7 ′ discharged from the unreacted gas separator S2 is caused to flow to the recycled gas storage line 11 by the gas switch C1 and is recycled to the recycled gas storage tank T1.
It is also stored in.

In the conventional device, CO₂In the separator S3
CO separated from DME 9 ' ₂8b 'is discarded
It has become so. In contrast, with the device of the present invention
Is a recycled CO₂8a 'is CO₂In storage tank T2
Stocked. CO₂CO in storage tank T2₂8a '
Is recycled in the gas mixer M2 via the flow control valve f1
It is adapted to be mixed with the gas 7a '. This is
This is for preparing the catalyst reducing gas 13a '.

The operation method of the above apparatus is as follows. (Reduction activation treatment of catalyst) A slurry bed in which a predetermined particulate catalyst is suspended in a predetermined medium oil is formed in a reactor R1 for DME synthesis. Next, the reduction activation treatment of the catalyst is performed by the following operation. Operate the gas switching valve as follows: Operate C1 so that the recycled gas storage line 11 leads to the recycled gas line 7a, C2 then C3 and the mixed gas line 12 leads to the reducing gas line 13, then 13a. To do. Thus, the recycled gas 11 'stocked in the recycled gas storage tank T1 and the recycled CO ₂ 8a' stocked in the CO ₂ storage tank T2 are taken out at a predetermined ratio by the flow control valves f1 and f2, respectively. The mixed gas 12 'is prepared by the gas mixer M2. Instead of using an inert gas in order to adjust the reducing performance of the reducing gas mildly, it is characterized in that CO ₂ (recycled CO ₂ 8a ′) which is an oxidizing gas is used as described above. Then, gas switching valves C2 and C3
And is supplied to the reactor R1 from the reducing gas line 13a. In determining the catalyst reduction conditions in the reactor R1, it is important to optimize the temperature raising rate, the ultimate temperature, and the reduction holding time at the ultimate temperature. Specifically, the type and particle size of the catalyst to be reduced, the mixing ratio of the catalyst components, the catalyst concentration in the medium oil, and the component composition and space velocity of the reducing gas (reducing gas in the standard state per 1 kg of catalyst) Supply rate). Usually, the temperature is gradually raised from room temperature to about 200 to 230 ° C. over several hours to finally gradually reduce the CO ₂ concentration in the reducing gas to 0. Hold for about 4 hours.

(DME synthesis reaction method) Make-up gas is produced from raw material natural gas, DME is synthesized in a reactor, and reaction intermediate, unreacted gas and product are separated from reaction product gas to obtain DME. to recover. The method is as follows. After the reduction activation process of the catalyst is completed, the flow rate control valves f1 and f2 are closed. Then, the gas switching valve is changed as follows. C1 so that the CO ₂ line 7 leads to 7a
2 is operated so that the CO ₂ line 7a leads to 7 ′, and then C3 is connected to the synthesis gas line 2 connected to the outlet of the gas mixer M1 to 2a. Natural gas 14 'is reformed with water vapor 15' to produce makeup gas 1'having H ₂ and CO as main components. Makeup gas 1'and recycled gas 7a "
And DM mixed in the gas mixer M1 and adjusted in this way
E synthesis gas 2'is fed to reactor R1. DME synthesis is performed in the reactor R1 under predetermined reaction conditions. The reaction product gas 3 ′ flowing out from the reactor R1 includes reaction products such as dimethyl ether and CO ₂ , reaction intermediates such as methanol and water, unreacted gases H ₂ and CO, and a small amount of impurity gas in natural gas. It is included. First, the reaction product gas 3'is added to the methanol / water separator S1.
At this point, for example, the condensation temperature difference is used for the treatment to separate methanol and water 4 '. Next, the reaction product gas 5'is treated in the unreacted gas separator S2 by utilizing, for example, a condensation temperature difference or a chemical absorption process to separate unreacted H ₂ and CO-based recycled gas 7'and recycle it. Flow to gas line 7. On the other hand, DME and CO ₂ 6 ′ separated from the recycled gas 7 ′ enter the CO ₂ separator S 3.

On the other hand, dimethyl ether and CO ₂ 6 '
Enters the CO ₂ separator S3, and the recycled CO ₂ 8a 'is separated and collected. The recycled CO ₂ 8a ′ is stocked in the CO ₂ storage tank T2. Then, in the reduction activation treatment of the catalyst, it is appropriately used as a reducing performance mild gas of the catalyst reducing gas 13a '. DME 9 ′ from which CO ₂ has been separated is recovered as a product. On the other hand, in the recycled gas 7 ′ separated by the unreacted gas separator S2, trace gas products such as methane and CO ₂ which has not been separated by the unreacted gas separator are mixed.
When these gas components are gradually accumulated in the recycled gas, the CO conversion rate gradually decreases as a result. Therefore, C
In order to maintain the O conversion rate at a predetermined level, conventionally, a part of the recycle gas 7'is withdrawn and purged to prevent accumulation of gas other than the reaction raw material components in the recycle gas. The recycled gas 7'is supplied to the recycled gas storage line 11 and stocked in the recycled gas storage tank T1. And, as mentioned above,
It is used as a reducing gas in the catalytic reduction activation process.

The recycle purge gas 10 'in the conventional dimethyl ether producing apparatus shown in FIG. 3 may be used as it is as the reducing gas in the reduction activation treatment of the catalyst. As described above, in the recycle purge gas 10 ', CO ₂ is 5 to ₂₀ vol.% Depending on the operating conditions of the unreacted gas separator S2 in addition to carbon monoxide and hydrogen.
This is because it may be included.

(Catalyst) Reactor R for dimethyl ether synthesis
As the catalyst used in 1, the above-mentioned reaction (1)-
In order to proceed each reaction of (3) to synthesize DME,
Using a methanol synthesis catalyst and a methanol dehydration catalyst,
Optionally, an aqueous shift reaction catalyst is added. These catalysts are mixed and used.

As the methanol synthesis catalyst, usually used are industrially used copper oxide-zinc oxide, zinc oxide-chromium oxide, copper oxide-zinc oxide / chromium oxide, copper oxide-zinc oxide / alumina and the like. As the methanol dehydration catalyst, γ-alumina, silica, silica
Alumina and zeolite are used. Here, as the metal oxide component of zeolite, oxides of alkali metals such as sodium and potassium, and oxides of alkaline earth such as potassium and magnesium are used. In addition,
Since the methanol synthesis catalyst has a strong shift catalytic activity, it can also serve as a water gas shift catalyst. As described above, an alumina-supported copper oxide catalyst can be used as both a methanol dehydration catalyst and a water gas shift catalyst.

The mixing ratio of the above three catalysts is not particularly limited and may be appropriately selected according to the type of each component, reaction conditions and the like. However, usually, the weight ratio of methanol dehydration catalyst to methanol synthesis catalyst 1 is about 0.1 to 5, preferably about 0.2 to 2, and water gas catalyst is 0.
2 to 5 and preferably about 0.5 to 3 are mixed.
When the methanol synthesis catalyst and the water gas shift catalyst are the same substance and the methanol synthesis catalyst also serves as the water gas shift catalyst, the total amount of both catalysts is used.

Regarding the form of the catalyst, when a slurry bed type reactor is used, the average particle size is 300 μm or less, preferably 1 to 200 μm, more preferably 10 to 150 μm.
It should be crushed to some extent. In order to use it more effectively, the mixed powder is appropriately compacted, molded, and pulverized again,
The one prepared to the above particle size is used.

(Medium Oil) When using a slurry bed reactor, the medium oil must be one that can maintain a stable liquid state under the reaction conditions. For example, aliphatic, aromatic and alicyclic hydrocarbons, alcohols, ethers, esters and ketones, and mixtures of these compounds are used. The amount of the catalyst to be present in the solvent can be appropriately determined depending on the type of the solvent, the reaction conditions and the like, but is usually desirable to be about 1 to 50% by weight based on the solvent.

(Reaction conditions) As the reaction conditions in the slurry bed reactor, the reaction temperature is preferably in the range of 150 to 400 ° C, and particularly preferably in the range of 250 to 350 ° C. Even if the reaction temperature is lower than 150 ° C. or higher than 400 ° C., the conversion rate of CO in the raw material gas is low. The reaction pressure is preferably in the range of 10 to 300 Kg / cm ² G, particularly preferably in the range of ^{20 to} 70 Kg / cm ² G.
Required reaction pressure 10 Kg / cm ² less and CO conversion rate of lower than G, whereas if greater than 300 Kg / cm ² G, except that the reactor becomes a special, a large amount of energy for Noborinetsu So not economical. Space velocity (catalyst 1kg
The supply rate of the raw material gas in the standard state is 1
0-50000 Nl / kg · h is desirable, especially 50
0 to 30000 Nl / kg · h is desirable. When the space velocity is higher than 50000 Nl / kg · h, the CO conversion becomes low, while when it is lower than 100 Nl / kg · h, the reactor becomes extremely large, which is not economical.

Reaction product thus obtained in the reactor R1
The composition of the gas 3'is C-mol%, and DME:
5-20%, CO₂: 5-30%, CO: 20-50
%, H ₂: 20-50%, CH₃OH: 1-10%, H
₂O: 1-10%, CH_Four: 0-5% and others: several%
It is below the level.

[Second Embodiment] FIG. 2 shows a flow sheet of another example of the dimethyl ether producing apparatus for carrying out the method of the present invention. In FIG. 2 , 18 is a source gas make-up.
Up compressor, R1 is a synthetic reaction of dimethyl ether
A reactor for performing reaction, 23 is a reaction discharged from the reactor R1
It is a product separator for separating unreacted gas from products .
Then, the catalyst used in the synthesis reaction is returned to this manufacturing device.
The original activation treatment is performed, and the treated catalyst is supplied to the reactor R1.
A reduction treatment reaction tower R3 is provided for this purpose . Return shop
The physical reaction tower R3 has a low pressure spray from the catalyst slurry tank 24.
A catalyst in a slurry state (reactor) via the rally pump 25
Suspended in the high boiling point medium oil used in R1)
Is provided for supplying the slurry . Also, reduction
A product separator 23 separates the lower portion of the processing reaction tower R3.
Recycled gas that supplies the unreacted gas to the reactor R1
Gas line 7b branched from the line is connected
The unreacted gas is supplied via the flow rate adjusting valve f3.
Growling . Also connected to the upper part of the reduction treatment reaction tower R3
The pressure in the tower is adjusted to the off gas line 16
A pressure adjusting valve A1 is provided for this purpose . Also, off gas
In line 16, raw gas make-up compressor
18 branched off from the makeup gas line on the discharge side
A gas line is connected, and if necessary, reduction treatment
Increase the pressure in the tower R3 to the pressure on the inlet side of the reactor R1
You can do it . Also, reduction treatment reaction tower
A slurry line 20 is provided between the lower part of R3 and the reactor R1.
Is installed and the reduced catalyst slurry is
It is supplied to the reactor R1 via a regulating valve.
It 22 is a high-pressure slurry pump, and 21 is a heater .

In addition to performing the reduction activation process with the above apparatus,
The high-pressure slurry pump 22 uses the catalyst slurry after the reduction.
At the same time that the deactivated catalyst inside the reactor is withdrawn via the high-pressure valve A4 to the outside of the reactor R1, the catalyst inside the reactor R1 can be replaced while maintaining the operating state. it can.

[Reduction activation] Recycle gas (unreacted gas) from the DME synthesis process contains unreacted raw material hydrogen and carbon monoxide gas as main components, and a large amount of carbon dioxide produced in the DME synthesis reaction. ing. Since carbon dioxide is an oxidizing gas, the reducing performance of reducing gases such as hydrogen and carbon monoxide is mild. Therefore, the reducing gas having a mild reducing performance required for the reduction activation treatment can be used for the reduction treatment of the catalyst slurry without using an inert gas such as nitrogen.

The pressure conditions of DME synthesis reaction, is a 30 to 50 kg / cm ² G or more high pressure as described above, using the method of the above embodiments, is connected to a reduction treatment reactor R3
Gas from the discharge part of the compressor 18
In and the slurry line 20 in a closed state , the product
Recycled gas (unreacted gas) separated by the separator 23
Is supplied to the reduction treatment reaction tower R3 , 10 kg / cm ²
While adjusting the pressure to about G, a predetermined flow rate of unreacted gas
It can be fed into the reduction treatment reaction tower . For this reason
A means for increasing the pressure of the original gas to about 10 kg / cm ² G is installed.
Without reaction, supply unreacted gas to the reduction treatment reaction tower R3
You can do it . In this way, the reduction treatment of the new catalyst can be simultaneously performed during the DME synthesis operation.

After the reduction treatment, inside the DME synthesis reactor
When it becomes necessary to replace the deactivated catalyst of the
Gradually open the reducing gas inlet / outlet gas line in the tower,
The reduction treatment reaction tower is pressurized with the presser discharge pressure. material
Gas make-up gas compressor discharge pressure is DM
E Several to several tens of Kg / cm more than the reaction pressure of the E synthesis reactor ²
Since the G is high, after the reduction catalyst reaction tower is pressurized,
If the valve of the slurry line from the
Reduction treatment reaction by self pressure without using slurry pump etc.
The catalyst slurry that has been reduced from the tower is the DME synthesis reactor
Will flow into.

In order to avoid mixing of the deactivated catalyst with the new catalyst inside the reactor, part or most of the old catalyst in the DME synthesis reactor is slurried in the DME synthesis reactor in the catalyst replacement work. A method in which a new catalyst slurry is charged into the DME synthesis reactor after being taken out is preferable.
Since the DME synthesis reaction is a strongly exothermic reaction, the amount of heat of the reaction that occurs as the catalyst slurry is withdrawn from the reactor is reduced, and thus the catalyst withdrawal operation does not cause a runaway reaction in the reactor.

The freshly fed slurry was preheated to D while maintaining the continuous operation of the DME synthesis reactor.
It may be charged into the ME synthesis reactor.

[0042]

EXAMPLES Next, the present invention will be further described with reference to examples.
It As an example of the method of the present invention, a diagram as shown in FIG.
Laboratory scale dimethyl ether based on the equipment shown in 1.
Use the synthesizer to return the recycled purge gas alone to the catalyst.
Performed a test using as a reducing gas for original activation
It was As a comparative example, the reducing performance of reducing gas was
H using nitrogen to convert₂And CO and N ₂Tokara
The test was performed using a mixed gas of

Tables 1 and 2 show the test conditions for the reduction activation of the catalyst and the test conditions for the synthesis of dimethyl ether in each case of Examples and Comparative Examples. And Table 3
The reaction results of the reduction treatment catalysts in Examples and Comparative Examples are shown in FIG.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

The reaction has an inner diameter of 90 mm and a height of 2000 mm.
The slurry-bed reactor of No. 1 is used, and a copper-zinc-aluminum-based catalyst having an average particle size of about 50 microns and a copper-
A DME synthesis main raw material gas is circulated through a slurry catalyst layer in which 1100 g of a fine powder catalyst prepared by mixing an aluminum-based catalyst in a weight ratio of 2: 1 is suspended in 7600 g of n-hexadecane, and a reaction product is a gas. It was analyzed by chromatography.

From the above results, it can be seen from the comparison between the example and the comparative example that sufficient reaction results for dimethyl ether synthesis are obtained by the catalyst activation method of the example.

[0049]

As described above, according to the present invention,
Without using a booster compressor for catalyst reducing gas, a high-pressure slurry pump for catalyst slurry, etc., and without obtaining a large amount of inert gas such as nitrogen from outside the plant, and suspending the operation of the reactor. It becomes possible to carry out the reduction treatment of the catalyst slurry and the exchange of the catalyst slurry in the DME synthesis reactor while maintaining the operating state without the work of opening and exchanging the catalyst. A method for reducing and activating such a dimethyl ether synthesis catalyst can be provided, and industrially useful effects are brought about.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an example of a dimethyl ether production apparatus for carrying out the method of the present invention.

FIG. 2 is a flow sheet of another example of a dimethyl ether production apparatus for carrying out the method of the present invention.

FIG. 3 is a flow sheet showing an example of a manufacturing apparatus used for directly synthesizing dimethyl ether from a conventional synthesis gas containing carbon monoxide and hydrogen as main components.

FIG. 4 is a schematic flow sheet of an experimental device using an example of the present invention.

[Explanation of symbols]

1 Makeup gas line 1'Makeup gas 2, 2a Syngas line 2'Syngas 3 Reaction product gas line 3'Reaction product gas 4 Methanol / water line 4'Methanol and water 5 Reaction product gas line (including DME, CO ₂ ) 5'reaction product gas (including DME, CO ₂ ) 6 DME / CO ₂ line 6'DME and CO ₂ 7, 7a recycle gas line 7 ', 7a', 7a ", 7b 'recycle gas 8a CO ₂ recycle line 8a 'recycled CO ₂ 8b CO ₂ disposal line 8b' waste CO ₂ 9 DME line 9 'DME 10 purge line 10' purge 11 recycle gas reservoir line 11 'recycle gas 12 mixed gas line 12' a mixed gas 13,13a reducing gas line 13 ', 13a' reducing gas 14 natural gas line 14 'natural gas 15 steam line 15' steam 1 6 Off-gas line 17 Make-up gas line 18 Raw-material gas make-up compressor 19 Discharge port 20 Slurry line 21 Heater 22 High-pressure slurry pump 23 Product separator 24 Catalyst slurry tank 25 Slurry low-pressure pump 26 Recycle compressor 27 Gas chromatography R1 reactor (DME synthesis) R2 reformer S1 methanol / water separator S2 DME / CO ₂ separator S3 CO ₂ separator T1 recycled gas storage tank T2 CO ₂ storage tanks f1, f2 flow control valves f3, f4, f5 flow control valve M1, M2 gas mixers C1, C2, C3 gas selectors A1, A2, A3 pressure adjusting valve A4 pressure reducing valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C07C 43/06 C07C 43/06 (72) Inventor Keiji Tomura 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Within Nippon Kokan Co., Ltd. ( 56) References JP-A-60-261540 (JP, A) JP-A-53-79811 (JP, A) JP-A-3-181435 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01J 21/00-38/74 C07B 61/00

Claims (3)

(57) [Claims] The method according to claim 1 syngas containing carbon monoxide and hydrogen are reacted with a catalyst, in the synthesis of dimethyl ether
A method for reducing and activating a catalyst to be used , comprising recycling of unreacted carbon monoxide and hydrogen separated from a reaction gas discharged from a dimethyl ether synthesis reactor.
Gas reduces catalyst used for dimethyl ether synthesis reaction
A method for reducing and activating a dimethyl ether synthesis catalyst, which is used as a reducing agent during activation treatment . 2. Dimethyl ether synthesis from recycled gas
As a reducing agent for the reduction activation of the catalyst used in the reaction
When used as a recycled gas,
The main component is carbon dioxide separated in the process after gas separation.
The gas according to claim 1, wherein a gas is added.
Method for reductive activation of chill ether synthesis catalyst. 3. Touch syngas containing carbon monoxide and hydrogen
A dimethyl ether synthesis reaction is performed using
Unreacted gas separated from the reaction gas discharged from the reactor
A dimethyl ether synthesis system for circulating the dimethyl ether to the synthesis reactor
Equipment for reducing the catalyst used in the synthesis reaction.
And a reduction treatment counter for reducing and activating the catalyst.
A reaction tower is provided to supply a catalyst to this reduction treatment reaction tower.
Line and the recycling gas line connected to the synthesis reactor
Gas line branched from the in, and reduction treated catalyst
Is connected to a line for sending the
Used in the synthesis reaction while the chill ether synthesizer is operating
Dimethyl configured to enable catalytic reduction treatment
Reduction treatment equipment for ether synthesis catalysts.