KR101431328B1 - Preparation method of ethanol through synthesis gas using a ferrieirite catalyst - Google Patents

Abstract

The present invention relates to a process for producing dimethyl ether by hydrogenating a synthesis gas for selectively producing ethanol by using a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide (step 1) (Step 3) of producing ethanol as a main product and acetic acid as a by-product, and a step (3) of producing ethanol as a main product and a byproduct And separating the separated byproducts of acetic acid and methanol into an esterification reaction to prepare methyl acetate and recycling it to step 3 (step 4).
In the present invention, as a catalyst system, a novel ferrierite catalyst and a layer inversion fluidized bed technology have been introduced as a method for simplifying the reaction process, whereby ethanol can be selectively produced at a high yield and the efficiency of carbon utilization can be increased There is an effect. Also, an alcohol fuel, which is widely regarded as an alternative energy source due to depletion of petroleum resources, can be produced directly from syngas by a catalytic chemical and economical conversion method.

Description

[0001] The present invention relates to a process for producing ethanol from a syngas using a ferrierite catalyst,

The present invention relates to a method of using ferrierite catalysts in the step of producing methyl acetate in a series of reaction processes to selectively produce ethanol using synthesis gas containing hydrogen, carbon monoxide and carbon dioxide.

The direct catalytic conversion of methanol to ethanol (EtOH) using conventional synthesis gas has a problem of low ethanol yield due to the formation of high byproducts, and the ethanol production method by commercial fermentation of sugars has a low yield due to a single conversion It has a problem.

Particularly, there is a problem in that a method of pretreating precious metal-based catalysts and copper-based catalysts, which are mainly used for the direct conversion reaction of synthesis gas, produces various alcohols and reduces the efficiency of the separation process [J. Catal. 261 (2009) 9-16, Catal. Today 120 (2007) 90-95, Fuel 86 (2007) 1298-1303]. The syngas is a gas containing CO / H ₂ / CO ₂ , which is reformed using hydrocarbons such as natural gas [Chem. Rev. 2007, 107, 3952-3991], and a gas having an H ₂ / CO ratio of less than 1 produced through gasification of coal and biomass, and a gas containing an excessive amount of CO ₂ . Especially, as a by-product gas in the steel industry, the synthesis gas containing mainly CO / H ₂ / CO ₂ is used as a synthesis gas. .

Particularly, as the development of clean energy resources becomes increasingly important due to the depletion of global petroleum resources, researches on next generation fuel development are being actively carried out. In parallel, the use of ethanol-gasoline mixture fuel for environmental improvement gradually increases Is expected to do [Licht FO (Eg, LanzaTech technology), which utilizes existing fermentation technology or synthesizes useful high value chemical substances such as ethanol by using syngas such as by-product gas, There is a growing demand for development of new technologies with excellent economy.

In the present invention, in order to develop a catalyst process for selectively producing ethanol from syngas, a step of synthesizing dimethyl ether (DME) through a hydrogenation reaction of synthesis gas, a step of synthesizing dimethyl ether (DME) by a carboxylarion reaction The aim of this study was to develop a catalytic process for the selective synthesis of ethanol while minimizing the formation of by - products through the unit catalytic reaction process including methyl acetate (MA) synthesis step and ethanol synthesis step by hydrogenation reaction of methyl acetate.

As a result of studies on the synthesis of methyl acetate (MA) using dimethyl ether (DME) as a method for synthesizing ethanol using a conventional synthesis gas, dimethyl ether (DME) using a mordenite catalyst Methyl acetate (MA) synthesis reaction through the carboxylation reaction of [Angew. Chem. Int. Ed. (DME) and methyl acetate (MA) were synthesized by direct synthesis gas synthesis and the reaction using Cu-ZnO / Mordenite hybrid catalyst to synthesize ethanol using this synthesis gas [ Ind. Eng. Chem. Res. 49 (2010) 5484-5488]. The above results show that mordenite catalyst was used for the carboxylation reaction of dimethyl ether (DME), and the selectivity of methyl acetate (MA) was excellent especially at high CO / DME ratio. The hydrogenation reaction was more favorable as the ratio of H ₂ / MA was higher.

In addition, U.S. Patent Application No. 2011-0124927 proposes a process conceptual diagram for selective ethanol synthesis, which comprises the steps of synthesizing dimethyl ether (DME) using synthetic gas derived from biomass, The synthesis of methyl acetate (MA) through the carboxylation reaction and the hydrogenation reaction using it and the recycling of the unreacted materials have been reported, but the contents of related catalysts and reaction conditions are not included.

In addition, U.S. Patent Application No. 2007-02705111 and U.S. Patent Application No. 2009-0221725 disclose that a mixture of methanol, methyl acetate, acetic acid, and the like is reacted with Ir, Cu, or Rh-based catalyst using methanol (MeOH) And synthesized ethanol through hydrogenation of methyl acetate. However, the description of the whole process is included rather than the detailed description of the catalyst system and reaction conditions.

Therefore, the present inventors have studied to increase the carbon utilization efficiency and the selectivity of ethanol in the entire reaction process by minimizing the formation of byproducts, and in the stage of producing methyl acetate, the selectivity of ethanol And the carboxyation of dimethyl ether (DME) and the hydrogenation of methyl acetate (MA) can be carried out through a single integrated process through the introduction of a layer inversion fluidized bed technique, The efficiency and the selectivity of ethanol can be greatly increased. Thus, the present invention has been completed.

It is an object of the present invention to provide a method of using ferrierite catalyst in the step of producing methyl acetate in a series of reaction processes in order to selectively produce ethanol using synthesis gas containing hydrogen, carbon monoxide and carbon dioxide .

In order to solve the above problems, the present invention provides a process for producing dimethyl ether by hydrogenating a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide (Step 1, R1); In the presence of ferrierite catalyst, carboxymidation reaction of dimethyl ether to produce methyl acetate (step 2, R2); Hydrogenating methyl acetate to produce ethanol as a main product and acetic acid as a by-product (steps 3 and R3); And a step (4) of separating ethanol and a by-product, which are the main products of step 3, and recycling the separated by-products, acetic acid and methanol, to produce methyl acetate and recycling it to step 3 Lt; RTI ID = 0.0 > ethanol. ≪ / RTI >

Synthetic gas containing hydrogen, carbon monoxide and carbon dioxide, which are reactants for the above reaction, can be produced through reforming using hydrocarbon such as natural gas, which is a general method, and gasification of coal and biomass, It is also possible to utilize the byproduct gas as a method for increasing the amount of syngas. The synthesis gas to be produced preferably has a molar ratio of hydrogen to carbon monoxide of 0.8 to 2.5.

The above step 1 is a process for synthesizing dimethyl ether (DME; CH ₃ OCH ₃ ) through a hydrogenation reaction of syngas (R1) using known mixed catalyst Cu-ZnO / Zeolites [Appl. Catal. B: Environ. 126 (2012) 1-8].

Step 2 is a reaction (R2) for synthesizing methyl acetate (MA; CH ₃ COOCH ₃ ) by the carboxylation reaction of the synthesized dimethyl ether in the presence of a ferrierite catalyst. In the case of using ferrierite catalyst, higher methyl acetate selectivity can be secured. The proportion of methyl acetate in the product of step 2 may be 80% or more.

Step 3 is a reaction (R3) for selectively synthesizing ethanol (CH ₃ CH ₂ OH) through hydrogenation of the synthesized methyl acetate. It can be easily converted using a conventional Cu-ZnO-based hydrogenation catalyst Do.

Step 4 is a step (R4) of preparing methyl acetate by esterification reaction of acetic acid (AA; CH ₃ COOH), which is mainly produced as a by-product in the hydrogenation reaction of methyl acetate, and recycling it to step 3 Methyl acetate is further synthesized to increase the carbon utilization efficiency of the entire process. The reaction scheme and characteristics of each reaction synthesis unit process can be expressed as follows.

(R1) DME _{synthesis: 2CO + 4H 2 = CH 3} OCH 3 + H 2 O

-> Cu-ZnO / Zeolites hybrid catalyst (T = 200 ~ 250 ℃, P = 30 ~ 50 bar)

(R2) DME carboxy _{Chemistry: CO + CH 3 OCH 3 =} CH 3 COOCH 3

-> Perrierite catalyst (T = 150 to 300 ° C, P = 5 to 30 bar)

(R3) MA hydrogenation _{half: CH 3 COOCH 3 + H 2} = CH 3 CH 2 OH + CH 3 OH

-> Cu-ZnO-based catalysts or noble metal-supported catalysts (T = 150 to 300 ° C, P = 5 to 30 bar)

(R4) Esterification of acetic _{acid: CH 3 COOH + CH 3 OH} = CH 3 COOCH 3 + H 2 O

-> Perrierite catalyst (T = 150 to 300 ° C, P = 5 to 30 bar)

Hereinafter, the present invention will be described in detail.

The reaction process for selectively synthesizing ethanol from the syngas can be composed of four unit reaction processes as shown in FIG.

First, step 1 is a synthesis reaction of DME using a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide as a reactant. This reaction can be carried out using a two-step process of DME synthesis by synthesis of methanol (MeOH) and subsequent methanol dehydration reaction, or a direct reaction process of synthesizing DME directly from a synthesis gas. Likewise, the reaction can be carried out using a fixed-bed reactor and a slurry reactor at a reaction temperature of T = 200 to 250 ° C and a reaction pressure of P = 30 to 50 bar using Cu-ZnO / Zeolites hybrid catalyst. DME and unreacted synthesis gas can be directly used in the R2 reaction by separating DME and unreacted synthesis gas from the distillation column (S1), which is a DME separation process. As a byproduct, methanol is converted into DME synthesis reactor R1 The conversion and the product distribution for direct DME conversion of general synthesis gas are shown in Examples 1 and 2 of Table 1 below.

Step 2 is a catalytic reaction process for synthesizing methyl acetate (MA; CH ₃ COOCH ₃ ) by DME carboxylation reaction using DME and syngas separated in the separation step in the presence of ferrierite catalyst. The reaction can be carried out at a reaction temperature of T = 150 to 300 ° C and a reaction pressure of P = 5 to 30 bar using a perryite catalyst. After the carboxylation reaction of DME, the product MA, the unreacted DME and the synthesis gas are separated in the separation step S2, and the MA and the synthesis gas as the unreacted product are directly introduced into the hydrogenation reaction (R3) of the subsequent process MA, Some of the syngas can be recycled to the DME synthesis reaction R1. At this time, the unreacted DME is recycled to the R2 process and used for the carboxyation reaction of DME. In this case, in order to secure a higher MA selectivity, the ferrierite catalyst proposed in the present invention can be selectively used. Further, a Zr-ferrierite catalyst in which Zr is ion-exchanged or supported at 1 to 10 wt% can be used in the present reaction by calcining at 500 ° C in an air atmosphere. The results of the car- boxylation reaction of DME using the ferrierite catalyst proposed in the present invention are shown in Examples 3 and 4 below. Also, the results of the carboxyation reaction of DME using mordenite catalyst reported in the previous study for comparison are shown in Comparative Example 1.

Next, Step 3 is a catalytic process for producing ethanol (EtOH) through hydrogenation of MA generated in R2. This reaction is carried out by using a commonly known Cu-ZnO catalyst and a noble metal-supported catalyst (Pt, Ru, Rh Etc.). The hydrogenation reaction can be carried out under the reaction conditions similar to the carboxyation reaction of DME at a reaction temperature T = 150 to 300 ° C, and a reaction pressure P = 5 to 30 bar. The product of the hydrogenation reaction of MA is separated into the product, ethanol, which is the main product, after the separation process of S3, and the unreacted synthesis gas can be recycled and reused for the R3 reaction. In addition, methanol produced as a by-product can be used in the DME synthesis reaction or in the MA production reaction through the esterification reaction with acetic acid (AA) as a main by-product. In the present invention, the hydrogenation reaction of MA is performed using a general hydrogenation catalyst of Cu-ZnO series, and the hydrogenation reaction result of MA is shown in Example 5 below.

Finally, step 4 is an esterification reaction for conversion of AA, which is a major by-product of the hydrogenation reaction of MA, through which MA is further synthesized to increase the carbon utilization efficiency of the entire process. MA produced through this reaction can be recycled to the R3 reaction stage and can be recycled by using a conventional zeolite (ZSM5, ferrierite, mordenite, etc.) And the reaction pressure P = 5 to 30 bar. In addition, a Zr-ferrierite catalyst in which Zr is ion-exchanged or supported at 1 to 10 wt% can be used in the present reaction by calcining at 500 DEG C under an air atmosphere. In the present invention, an esterification reaction of AA was carried out using a ferrierite acid catalyst. The reaction results are shown in Example 6 below.

The reaction (R1) for directly synthesizing DME from the above-described synthesis gas was carried out using a Cu-ZnO / Zeolite hybrid catalyst at a reaction temperature of T = 200 to 250 ° C and a reaction pressure of P = 30 to 50 bar. And a slurry reactor. In the case of the reactions R2, R3 and R4 (steps 2 to 4), which are ethanol synthesis reactions using DME, the reaction temperature T = 150 to 300 ° C and the reaction pressure P = 5 ≪ / RTI > in a fluidized bed reactor in the presence of a ferrierite catalyst and a hydrogenation catalyst at < RTI ID = 0.0 > In this case, the lower portion of the fluidized bed reactor has low density catalyst particles having a density of 1100 to 1300 kg / m ³ , a particle size of 2.8 to 3.5 mm, and a density of 2300 to 2600 kg / m ^{3 at} the upper end There are high-density catalyst particles having a particle size of 0.3 to 0.5 mm in size. The reaction process using the fluidized bed reactor using the layer inversion technique is as shown in FIG.

2, when a catalyst having different densities and particle sizes as shown in FIG. 2 is used in the same reactor and operated at a constant flow rate, the particles having a low density and a large size are fed to the lower portion of the fluidized bed reactor And the high density and small size particles are mainly distributed in the upper part of the fluidized bed reactor, and can be carried out simultaneously in a fluidized bed reactor having two reactions. For this purpose, the low density catalyst particles have a density of 1100 to 1300 kg / m ³ , the particle size needs to be 2.8 to 3.5 mm, the high density catalyst particles have a density of 2300 to 2600 kg / m ³ , The particle size needs to be 0.3 to 0.5 mm in size. In addition, superficial liquid velocity needs to be operated in the range of about 30 to 60 mm / s for an effective layer inversion phenomenon.

According to this, it is possible to implement three unit reaction processes (R2 + R3 + R4) in one reactor, thereby increasing the process efficiency and the carbon utilization efficiency by integrating the unit reaction process R2 + R3 + R4 . In this case, a ferrierite catalyst is present in the lower portion of the fluidized bed reactor, a step of carboxylating the dimethylether to produce methyl acetate takes place, and a Cu-ZnO-based catalyst for hydrogenation is present at the upper end of the fluidized bed reactor A step of hydrogenating methyl acetate to produce ethanol takes place and acetic acid prepared as a byproduct with ethanol is fed to the lower end of the fluidized bed reactor to perform esterification reaction in the presence of a ferrierite catalyst to produce methyl acetate.

That is, in the reaction proposed in the present invention, the synthesis of DM by the reaction of CO and DME is selectively carried out by performing the carboxylation reaction of DME at the lower end of the fluidized bed reactor using synthesis gas containing hydrogen, carbon monoxide and carbon dioxide, At the top, MA can be hydrogenated using an excess of H _2, which is an unreacted material, to produce ethanol. Therefore, in the lower part of the fluidized bed reactor, a ferrierite catalyst having a particle size within the above range is used as a catalyst system for the carboxidation reaction of DME. MA is selectively synthesized, and the esterification reaction of AA is carried out in the same zeolite The MA synthesis reaction can be carried out by reaction with methanol, which is a major by-product on the catalyst. In addition, a hydrogenation catalyst (Ru.RT.Pt. Supported catalyst) or a Cu-ZnO / Zeolite hybrid catalyst to which noble metal is added can be used as a catalyst system for synthesizing ethanol by progressing the hydrogenation reaction of MA at the upper end of the fluidized bed reactor have.

According to the method for selectively producing ethanol from the syngas according to the present invention, as a catalyst system for selectively producing ethanol from a syngas, a novel ferrierite catalyst and a layer inversion fluidized bed technology And ethanol can be selectively produced at a high yield, and the efficiency of carbon utilization can be increased. Also, an alcohol fuel, which is widely regarded as an alternative energy source due to depletion of petroleum resources, can be produced directly from syngas by a catalytic chemical and economical conversion method.

1 is a flow chart of a catalytic reaction process for selectively producing ethanol from a synthesis gas according to the present invention.
2 is a schematic diagram for application of a fluidized bed reactor using a layer inversion technique according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these examples are intended to illustrate the present invention, and the scope of the present invention is not limited by these examples.

Example  1: Hydrogenation of synthesis gas Dimethyl ether (DME)  Produce ( R1 )

The catalyst for the direct synthesis of dimethyl ether from the synthesis gas was prepared by first adding a zirconium (IV) oxychloride precursor (H ₂ O) on H-ferrierite (SiO ₂ / Al ₂ O ₃ = 20, specific surface area = 400 m ² / _{using; (ZrCl 2 O · 8H 2} O zirconium (IV) oxychloride octahydrate) was prepared to contain 3% by weight of zirconium metal, the prepared Zr- ferrierite (ferrierite) acetic acid on the slurry of the zeolite 1.61 g of copper monohydrate _{(Cu (C 2 H 3 O} 2) 2 · H 2 O) 5.05 g, zinc acetate hydrate _{(Zn (C 2 H 3 O} 2) 2 · 2H 2 O) 4.31 g and aluminum nitrate hydrate (Al (NO ₃ ) ₃ · 9H ₂ O) was used as a catalyst and 8.34 g of sodium carbonate was used as a precipitant. In the third distilled water, the metal mixed solution and precipitant solution prepared above were simultaneously slowly injected into Zr-ferrierite zeolite which is a slurry phase, and the final pH was maintained at 7.5 to 8.0 for 3 hours. After that, after washing and filtering, 12 Hour, and calcined at 350 DEG C for 5 hours in an air atmosphere to prepare a dimethyl ether synthesis catalyst.

The composition of the Cu-Zn-Al-based oxide on the catalyst after firing was 50 wt% of CuO, 40 wt% of ZnO and 10 wt% of Al ₂ O ₃ based on the metal oxide, -Zn-Al oxide was 2.3 weight ratio. The reaction was carried out in a fixed-bed reactor at a reaction temperature of 250 ° C, a reaction pressure of 40 kg / cm 3 and a space velocity of 5500 h ^-1 before the dimethyl ether synthesis reaction. The reaction was carried out under a hydrogen atmosphere at 250 ° C. for 4 hours. : The molar ratio of hydrogen: carbon dioxide was fixed at a ratio of 41%: 38%: 21% and injected into the reactor to perform the reaction. The results are shown in Table 1.

Example  2: Synthesis gas is hydrogenated Dimethyl ether (DME)  Produce ( R1 )

Dimethyl ether was prepared by varying the catalyst used in Example 1. As a catalyst for directly synthesizing dimethyl ether (DME) from a syngas, ferrierite catalyst (NH ₃ form) was calcined at 500 ° C for 5 hours and then converted to ferrierite catalyst (form H) An aqueous solution containing cupper nitrate (8.12 g), Zinc Acetate (2.46 g), Alumina nitrate (4.21 g) and ammonium carbonate (16.71 g) while keeping the ferrierite catalyst (H form, , Followed by aging at 70 ° C for 2 hours, followed by drying at 100 ° C for 24 hours and calcining at 300 ° C for 3 hours to prepare a dimethyl ether synthesis catalyst Respectively.

The reaction was carried out after reduction at 300 ℃ for 5 hours using the prepared catalyst. The composition ratio of the mixed gas used in the reaction was H ₂ = 62.8%, CO = 31.6% and N ₂ = 5.60%. The reaction was carried out using a fixed bed reactor and the pressure of the reactor was maintained at 35 bar. After the reaction was carried out at a rate of 2000 ml / g / h for 20 hours, conversion ratios and product distributions are shown in Table 1.

Example  3: Of dimethyl ether (DME) Carboxy  Through the reaction Methyl acetate  Synthetic reaction R2 )

As a method for synthesizing methyl acetate through the carboxylation process of dimethyl ether, a method of synthesizing methyl acetate using 500 g of ferricite (SiO ₂ / Al ₂ O ₃ = 20, specific surface area = 400 m ² / g) For 3 hours and then pretreated with N ₂ at 300 ° C for 5 hours before the carboxyation reaction of dimethyl ether. The molar ratio of reactant CO: DME: N ₂ was 45%: 5%: 50 at a reaction temperature of 220 ° C and a reaction pressure of 20 kg / cm 2 and a space velocity of 2000 L / kg cat / %, And the reaction was carried out by injecting into the reactor. The results are shown in Table 1.

Example  4: Of dimethyl ether (DME) Carboxy  Through the reaction Methyl acetate  Synthetic reaction R2 )

Methyl acetate was prepared by varying the catalyst used in Example 3. As a method for synthesizing methyl acetate (MA; CH ₃ COOCH ₃ ) by carboxymethylation of dimethyl ether (DME), H-ferrierite (SiO ₂ / Al ₂ O ₃ = 20, specific surface area = 400 m ² / g) to zirconium (IV) oxychloride precursor _{(ZrCl 2 O · 8H 2 O} ; zirconium (IV) phase using oxychloride octahydrate) was prepared to contain the zirconium metal of 0.5% by weight, the prepared Zr -ferrierite (ferrierite) was a zeolite at 500 ℃ 3 hours after firing used in the reaction, it was carried out through the process of pre-treatment at 300 ℃ 5 hours using a N ₂ before carboxymethyl reaction of dimethyl ether (DME). The molar ratio of reactant CO: DME: N ₂ was 45%: 5%: 50 at a reaction temperature of 220 ° C and a reaction pressure of 20 kg / cm 2 and a space velocity of 2000 L / kg cat / %, And the reaction was carried out by injecting into the reactor. The results are shown in Table 1.

Example  5: Of methyl acetate (MA)  Synthesis of Ethanol by Hydrogenation R3 )

As a catalyst for the synthesis of ethanol through hydrogenation of methyl acetate (MA), Cu, Zn, Al, Ga, and Strontium precursors were used to prepare CuO-ZnO-Al ₂ O ₃ -Ga ₂ O ₃ -SrO- copper acetate monohydrate _{(Cu (C 2 H 3 O} 2) 2 · H 2 O) 13.52 g, zinc acetate hydrate _{(Zn (C 2 H 3 O} 2) 2 · 2H 2 O) 6.83 g, aluminum nitrate hydrate (Al ( _{NO 3) 3 · 9H 2 O} ) 1.34 g, gallium nitrate hydrate _{(Ga (NO 3) 3 ·} H 2 O) 0.95 g and strontium nitrate compound _{(Sr (NO 3) 2)} 1.07 g of the distilled water of 500 mL , And a solution prepared by dissolving 13.17 g of sodium carbonate in 600 mL of tertiary distilled water was used as a precipitating agent.

Under the condition of 70 DEG C, 200 mL of the third distilled water, the metal mixed solution and the precipitant solution prepared above were slowly injected simultaneously to maintain the final pH at 7.5 to 8.0. At this time, the mixed solution was stirred at a temperature of 70 ° C for about 3 hours. The prepared catalyst (CuO-ZnO-Al ₂ O ₃ -Ga ₂ O ₃ -SrO = 58.0 / 29.7 / 3.15 / 3.49 / 5.66) The final catalyst had a specific surface area of 123.7 m ² / s, a weight ratio of CuO / ZnO of 1.95, and a specific surface area of 0.75 m ² / s. The catalyst for methanol synthesis was prepared by drying at 100 ° C. for 12 hours or longer. The SrO / CuO weight ratio was 0.098.

The catalyst was then calcined at 300 ° C. for 5 hours in an air atmosphere using a catalyst in powder form and then introduced into the reactor. Before starting the reaction, 0.2 g of the catalyst was reduced for 3 hours under hydrogen atmosphere at 250 ° C., and then the reaction was carried out using a fixed bed reactor. The reaction temperature was 250 ° C. and the reaction pressure was 10 kg / cm 2 and the space velocity was 16000 L / h, the molar ratio of hydrogen / methyl acetate as a reactant was fixed at a ratio of 5/1 and injected into the reactor to perform the reaction. The results are shown in Table 1.

Example  6: Acetic acid ( AA )of Esterification  By reaction Methyl acetate ( MA ) Synthesis Reaction ( R4 )

As a method for synthesizing methyl acetate (MA; CH ₃ COOCH ₃ ) by esterification reaction of acetic acid, H-ferrierite (SiO ₂ / Al ₂ O ₃ = 20, specific surface area = 400 m ² / g ) For 3 hours at 500 ° C. and pretreated with N ₂ at 250 ° C. for 2 hours before the esterification reaction of acetic acid (AA). The reaction was carried out in a liquid phase slurry batch reactor, and the molar ratio of methanol: acetic acid as a reactant was fixed at a ratio of 5: 1 at a reaction temperature of 120 ° C, a reaction pressure of 1 kg / cm 2 and a stirring rate of 1000 rpm, And the conversion of acetic acid and the selectivity of methyl acetate at the reaction time of 5 hours are shown in Table 1.

Example  7: Layer - inversion  Using technology Of methyl acetate (MA)  Ethanol synthesis reaction by hydrogenation reaction

Synthesis reaction was carried out using a fluidized bed reactor, which exhibited layer inversion characteristics, to selectively produce ethanol using syngas. The fluidized bed reactor needs to be operated at a constant flow rate by using a catalyst having different density and particle size in the same reactor. The characteristics and reaction conditions of the catalyst used in the fluidized bed reactor are as follows.

First, by using a catalyst system suitable for a fluidized bed reactor showing layer inversion characteristics, a ferrierite for MA synthesis (MA: CH ₃ COOCH ₃ ) mainly by the carboxylation reaction of dimethyl ether (DME) The catalyst was formed into large particles with low density and distributed mainly in the lower part of the fluidized bed reactor. In the upper part of the fluidized bed reactor, Cu-ZnO catalyst for the hydrogenation reaction of methyl acetate (MA) was formed into small particles having high density by using H ₂ as the unreacted material and mainly distributed in the upper part of the fluidized bed reactor.

In this experiment, a low-density particle (a catalyst for the carboxylation reaction of dimethyl ether corresponding to ferrierite) with a density of 1280 kg / m ^{3 and} an average particle size of 3.3 mm High density particles (corresponding to a catalyst for the hydrogenation reaction of methyl acetate) of 25 g / m ³ and a mean particle size of 0.385 mm were prepared by using 100 g of polymer beads sand) was used to observe layer inversion characteristics in a fluidized bed reactor. In order to induce an effective layer inversion phenomenon, the critical fluid velocity was operated at 45 mm / s, and effective layer inversion characteristics of low density particles and high density particles were observed.

Comparative Example  One: Of dimethyl ether (DME) Carboxy  By reaction Methyl acetate  Synthetic reaction

(Mordenite, SiO ₂ / Al ₂ O ₃ = 25, specific surface area = 350 m ² / g) as a method for synthesizing methyl acetate (MA; CH ₃ COOCH ₃ ) by carboxyation reaction of dimethyl ether, Was used for the reaction after calcination at 500 ° C. for 3 hours. Pretreatment was carried out at 250 ° C. for 2 hours using N ₂ before the carboxyation reaction of dimethyl ether. The reaction was carried out under the conditions of a reaction temperature of 250 ° C., a reaction pressure of 10 kg / cm 2 and a space velocity of 2000 L / kg cat / h, and the molar ratio of reactant CO: DME: N ₂ was fixed at a ratio of 60%: 6.7%: 33.3% The reaction was carried out in a reactor, and the results are shown in Table 1.

division CO conversion (mol%) Carbon selectivity
[MeOH / DME / CO ₂ / by-products] Yield (mol%) ¹⁾
(MeOH + DME) Example 1 49.1 7.8 / 58.2 / 33.7 / 0.3 32.4 Example 2 32.8 4.6 / 83.0 / 5.8 / 6.5 27.2 division DME conversion rate
(Mol%) Carbon selectivity
[MA / MeOH / CH ₄ / other hydrocarbons; Yield (mol%)
(MA) Example 3 17.4 85.9 / 4.5 / 2.5 / 7.1 14.9 Example 4 12.0 80.2 / 14.0 / 4.3 / 1.5 9.6 Comparative Example 1 11.8 7.4 / 21.7 / 3.0 / 67.9 0.87 division MA Conversion (mol%) Carbon selectivity
[EtOH / MeOH / AA / other hydrocarbons Yield (mol%)
(EtOH) Example 5 83.7 37.6 / 35.4 / 22.5 / 4.5 31.5 division AA conversion (mol%) Carbon selectivity
[MA / other hydrocarbons] Yield (mol%)
(MA) Example 6 48.3 99.0 / 1.0 47.8 1) is the mixed yield of the main product, the main by-product is the C ₁ -C ₄ hydrocarbon

As shown in the above Table 1, in the catalytic process for directly producing ethanol from the synthesis gas according to the method proposed in the present invention, dimethyl ether ( It is considered that Cu-ZnO / ferrierite catalyst is effective for the catalytic process of DME; CH ₃ OCH ₃ ) synthesis unit process (R1).

In the catalytic reaction step (R2) for synthesizing methyl acetate (MA; CH ₃ COOCH ₃ ) by the carboxyation reaction of dimethyl ether as in the cases of Examples 3 and 4, Ferrierite and Zr-ferrierite catalysts were found to be superior to mordenite catalysts of Zr-ferrierite catalysts. In the case of Zr-ferrierite catalysts, Compared with ferrierite, the conversion of dimethyl ether and the selectivity of methyl acetate were somewhat reduced, but the selectivity of methanol, which can be used as a reactant for the dimethyl ether synthesis reaction, The effect can be obtained.

The ferrierite catalyst used in the present reaction can be used in the same manner as in the methyl acetate synthesis catalyst reaction step (R4) by the esterification reaction of acetic acid (AA; CH ₃ COOH), which is a main by-product of the hydrogenation reaction (R ₃ ) It can be confirmed through the result of Example 6.

Further, as shown in Example 5, it was confirmed that the selective production (R3) of ethanol through the hydrogenation reaction of methyl acetate was possible when the commonly used catalyst for R1 reaction and Cu-ZnO catalyst were used. Therefore, we developed a technology that can apply the fluidized bed reactor using the layer inversion technology for the process development that integrates the R2 + R3 + R4 reaction as a method for increasing the efficiency of the reaction process and increasing the carbon utilization efficiency. As a result, it can be applied as an alternative method to develop alternative energy technology of petroleum based energy resources.

Claims (13)

Hydrogenation reaction of a synthesis gas containing hydrogen, carbon monoxide and carbon dioxide to produce dimethyl ether (step 1);
(Step 2), in the presence of ferrierite catalyst, carboxymidation reaction of dimethyl ether with synthesis gas to produce methyl acetate;
Hydrogenating methyl acetate to produce ethanol as a main product and methanol and acetic acid as by-products (step 3); And
Separating the main product of step 3 from ethanol and byproducts, and esterifying the separated by-product acetic acid and methanol to produce methyl acetate and recycling it to step 3 (step 4)
≪ RTI ID = 0.0 > 1, < / RTI >
The process according to claim 1, wherein the synthesis gas as the unreacted product of step 2 is recycled to produce the dimethyl ether of step 1, and the unreacted dimethyl ether is recycled to produce methyl acetate of step 2 ≪ RTI ID = 0.0 > 1, < / RTI >
The method according to claim 1, wherein the ferrierite catalyst is pretreated with 1 to 10% by weight of Zr.
The method of claim 1 wherein the ratio of methyl acetate in the product of step 2 is greater than 80%.
The method of claim 1, wherein the synthesis gas has a molar ratio of hydrogen to carbon monoxide of from 1: 0.8 to 2.5.
The process according to claim 1, wherein said step (4) takes place in the presence of a ferrierite catalyst.
2. The method of claim 1, wherein step 1 and step 3 occur in the presence of a Cu-ZnO catalyst.
The process according to claim 1, wherein said step 3 occurs in the presence of a supported noble metal catalyst selected from the group consisting of Ru, Rh and Ph.
The process according to claim 1, wherein the reaction temperatures of step 2, step 3 and step 4 are carried out at a temperature of from 150 to 300 ° C and at a pressure of from 5 to 30 bar.
The method of claim 1, wherein said steps 2 to 4 occur continuously in a fluidized bed reactor.
Of claim 10, has a has a density of 1100 to 1300 kg / m ³ the lower end of the fluidized bed reactor, the particle diameter is 2.8 to 3.5 mm in size, and the particles of low-density exists having an upper end, the 2300 to 2600 kg / m ³ according to Wherein the catalyst particles have a density of 0.3 to 0.5 mm and a particle size of 0.3 to 0.5 mm. ≪ RTI ID = 0.0 > 11. < / RTI >
11. The method of claim 10, wherein a ferrierite catalyst is present in the lower portion of the fluidized bed reactor, and the step of carboxylating the dimethyl ether to produce methyl acetate occurs,
In the upper part of the fluidized bed reactor, Cu-ZnO catalyst is present, and methanol is hydrogenated to produce ethanol.
Methanol or acetic acid prepared as a byproduct with ethanol is fed to the lower end of the fluidized bed reactor or esterification reaction is carried out in the presence of a ferrierite catalyst at the lower end of the reactor by convection in the fluidized bed reactor to produce methyl acetate ≪ RTI ID = 0.0 > 1, < / RTI >
11. The method of claim 10, wherein the fluid bed reactor fluid bed velocity is between 30 mm / s and 60 mm / s.

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