SU952101A3 - Process for producing dimethyl ester - Google Patents

Abstract

1398696 Dimethyl ether synthesis SNAM PROGETTI SpA 11 Dec 1973 [20 Dec 1972] 57443/73 Heading C2C Dimethyl ether is synthesized by reacting CO, CO 2 and H 2 in the presence of a catalytic body comprising a methanol synthesis catalyst and a methanol dehydration catalyst. In an example, the catalyst used is Cu/Zn/Cr in the atomic proportions 82/16/4 on alumina.

Description

The invention relates to methods for producing dimethyl ether ·, which is widely used in the chemical industry as a solvent. ⁵

A known method of producing dimethyl ether (DME) by reacting CO and Hg ^ O in the presence of COo_ using zinc-chromium or copper-oxide catalyst on alumina (up to 36 wt.%) As a carrier at a pressure of 30-400 atm and a temperature of 200- 400 ° C SP.

However, the known method does not provide the necessary selectivity with respect to dimethyl ether, which in this process is obtained only as a by-product of methanol by-product to the main product. ₂ о

The purpose of the invention is to increase the selectivity of the process.

This goal is achieved by the fact that according to the method of producing dimethyl ether by conversion of a mixture of ga. ₂₅ calls of CO, Hq, and CO _g at a temperature of 280,400 ° C and a pressure of 100-150 atm in the presence of an oxide zinc-chromium-containing catalyst and aluminum oxide, the process is carried out at a molar ratio of carbon monoxide to hydrogen from 0.56 to 1.16 per zinc -chrome-copper-aluminum catalyst.

It is preferable to use a catalyst made in the form of alternating layers of zinc-chromium-copper catalyst and alumina at a weight ratio of 1: 1, or to use the catalyst in the form of a mechanical mixture of these components.

The proposed method allows to achieve a relatively high selectivity of the process with respect to dimethyl ether (up to 67%).

Carrying out the reaction under such conditions can also significantly increase (increase the rate of conversion of CO, CO ^ and Η, χ in the reactor, since most of the intermediate methanol formed is dehydrated in DME as it forms, and the catalyst layers provide this process even at low methanol concentrations The specified catalyst activates the process of absorption by carbon monoxide: of water contained in the reaction mixture, which, in turn, significantly reduces the amount of unreacted gas that is returned to recycling, which gives an economical Technological and technological advantages.

In the process, you can use a mixture of gases CO ₄ , CC> 2 ^and , resulting from the oxidation of heavy hydrocarbons or coal gasification with a content of C0 5 up to 52 vol. % and Η, χ up to '20 vol. % With a high CO content and a low percentage of CO-χ, a high (up to 80%) degree of conversion is possible.

Example 1. In a reactor with a volume of Yu 5 m ³ load with alternating layers

3.4 m ^{3 of} copper-zinc-chromium oxide catalyst at an atomic ratio of 82:16:14, respectively, and 1.6 m ³ of aluminum oxide.

molded

A copper-zinc-chromium catalyst is formed into tablets having a diameter of b mm and a height of 5 mm, while balls of 5 mm diameter are made from alumina.

The weight ratio between the zinc-chromium zem catalyst is 1: 1.

A mixture of hydrogen, carbon monoxide and carbon dioxide at a percentage ratio of hydrogen: carbon monoxide: carbon dioxide 49: 49: 2 is supplied to the reaction apparatus at ..._____ a flow of 100,000 nm ³ / h and a space velocity of 20,000 h ' ^-1 . The molar ratio of CO is 1.00.

The excess pressure in the reactor is 150 kg / cm ¹ and the temperature is 300 ° C.

A stream comprising hydrogen, carbon monoxide, carbon dioxide, methane, methyl alcohol, dimethyl ether and water is diverted from the reaction apparatus. .

copper alumina- 25

The degree of conversion of CO * is 38%.

The selectivity for dimethyl ether (DME) is 69%, for methanol - 4.6%, for methane - 2%, and for carbon dioxide - 34.4%.

Then the reaction mixture is distilled and get pure DME.

Example 2. The source gas mixture of the following composition, wt.%:

'n _a . With 62.67 35,20 with _r 1.46 sun ₄ 0.37 0.30 At the molar ratio of CO and Η <χ 0.56 and space velocity 100,000 nm ³ / h serve into the reactor under pressure 100 kg / cm ^λ and temperature 250 C, pro

passing through the layered catalyst of the composition specified in example 1.

The reacted gas at the outlet of the reactor has the following characteristics:

Volumetric flow rate, nm ³ / h 5600

A

Composition, wt.%: H _q 48.58 With 8.45 C0 ₂ 17.45 SND 0.66 0.53 CH ₃ 0H 2.2 3 CH ₃ 0CH ₃ 18.48 Η <ζθ 3.32 Temperature ° C 270

100,000

1250 nm ³ / h of methyl alcohol and 10360 nm ³ / h of DME are obtained, which corresponds to a carbon monoxide conversion of 67%.

Take 3. Work under the conditions of example 2, but with the following characteristics of the initial mixture obtained by partial oxidation of heavy oils, 0 _g :

, Volume velocity) of the flow, nm ³ / h i · Composition, wt.% ·.

N O.

With

COH CH ₄ NI

Molar ratio

Temperature ° C

At the outlet of the reactor, the gaseous product has the following characteristics:

44.70

51.90

1.78

0.27

1.35

СО and Н ₂ 1,16

250 ‘A

Volumetric flow rate nm ³ / h 50350 Composition, wt.%: N _g 14.05 With 29.97 C0 <2. 27.30 . sn he 0.91 CH ₃ OCH ₃ 24.20 sun ₄ 0.54 N * 2.62 n _g o .0.41 Temperature ° C 270

g-d 2

In the end, get AN _? OH 460'nm '/ h 12150 nm ³ / h DME. The CO conversion is 77%.

PRI me R. 4. The catalyst is prepared by thoroughly mixing the powders of catalyst Cu, Zn, St at a ratio of 82: 16s4 and powders of alumina at a weight ratio of 1 ·. 1. The catalyst thus obtained is tableted in the form of particles with a diameter of 6 mm.

5 m ^{3 of} such a catalyst is introduced into the reactor, and then a gas mixture is supplied at a percentage ratio of Hi ^ sCOiCO ^ = 49: 49: 2, a molar ratio of СО and Ηη_ = 1.00, and a volumetric flow rate of 100000 nm ³ / h.

The temperature in the reactor is 250 ° C, and the pressure is 100 kg / cm ^g .

The effluent from the reactor consists of H _g , CO, CO-χ, CH ₄ , CHj0n, CHjO ,, CHj with a CO conversion of 27%. DME selectivity is 64%,

952101 6 for methanol - 7.8%, for CH ₄ - 1%, for СО _g - 27.2%.

Then the reaction mixture is distilled to obtain pure DME.

Example 5. The catalyst and the composition of the gas mixture are used with the characteristics specified in example 4.

At a process temperature of 300 ° C and a pressure of 100 kg / cm ^{2, the} conversion of CO is 35%, the selectivity for DME is 65%, for methanol - 2.1%, for CH ₄ - 1.5% -10 and for CO ^ - 31, 4*.

Example 6. The catalyst and the flow rate of the gas mixture described in example 4, is used at a temperature of 300 ° C and a pressure of 150 kg / cm ^. ,5

CO conversion is 40% with a selectivity for DME of 66%, for methanol - 2.2%, for CH ₄ - 1.8%, for CO <2 ~ 30%.

Claims (3)

The invention relates to methods for producing dimethyl ether, which is widely used in chemical production as a solvent. A known method for producing dimethyl ether (DME) by reacting CO and in the presence of CO using a zinc-chromium or copper oxide catalyst on alumina ( up to 36 wt.%) as a carrier at a pressure of 30-400 atm and a temperature of 200-400 ° C SI. However, the known method does not provide the necessary selectivity with respect to dimethyl ether, which in this process is obtained only as a by-product to the main product methanol. The purpose of the invention is to increase the selectivity of the process. This goal is achieved by the fact that according to the method of producing dimethyl ether by converting the mixture, ga-. Call of CO, H ,, and CO (i at a temperature of 280400 C and a pressure of 100-150 atm in the presence of an oxide zinc-chromium-containing catalyst and alumina, the process is carried out at a molar ratio of carbon monoxide to hydrogen from 0.56 to 1.16 zinc-chromium-copper-aluminum catalyst. It is preferable to use a catalyst made in the form of alternating layers of a zinc-chromium-copper catalyst and alumina at a weight ratio of 1: 1, or to use a catalyst in the form of a mechanical mixture of these components. high selectivity of the process with respect to dimethyl ether (up to 67%). Conducting the reaction under such conditions also allows a significant increase in the conversion rate of CO, CO2, and Hrj in the reactor / since most of the resulting intermediate methanol dehydrates in DME, and Catalyst layers provide this process even at low concentrations of methanol. The said catalyst activates the process of absorption by carbon monoxide, water contained in the reaction mixture. This, in turn, significantly reduces the amount of unreacted gas recycled, which provides economic and technological advantages. The process can use cm gases CO, CO2 and H5, resulting from the oxidation of heavy hydrocarbons or gasification of coal with a content of cd up to 52% by volume and H up to 20% by volume. With a high CO content and a low percentage of CO, it is possible to achieve a high 80% conversion) degree. Example 1. A 5 m reactor is loaded with alternating layers of 3.4 m of a copper-zinc oxide catalyst with an atomic ratio (82:16:14) and 1.6 m of alumina, respectively. A copper-zinc-chromium catalyst is formed into tablets, which are 6 mm in diameter, and 5 MMf in height, while alumina forms balls 5 mm in diameter. The weight ratio between the copper-zinc-chromium catalyst and the clay is 1: 1. A mixture of hydrogen, carbon monoxide and carbon dioxide at a percentage ratio of water genus: carbon monoxide: carbon dioxide 49: 49: 2 is fed into the reaction apparatus at a flow rate of 100,000 HMV4 and a space velocity of 20,000 h. The molar ratio of CO and Hfj is 1.00. The overpressure in the reactor is 150 kg / cm and the temperature is. A stream comprising hydrogen, carbon monoxide, carbon dioxide, methane, methyl alcohol, dimethyl ether and water is withdrawn from the reaction apparatus. The degree of CO conversion is 38%. Selectivity with respect to dimethyl ether (DME) is 69%, with respect to methanol - 4.6%, with respect to methane - 2%, and with respect to carbon dioxide - 34.4%. Then the reaction mixture is dispersed with y and get pure DME. Example 2. The initial gas mixture of the following composition, - wt.%: 67 CO35,20, 46 CHl0.37, 30 With a molar ratio of CO and H of 0.56 and a flow rate of 100,000 HMV are fed into the reactor under a pressure of 100 kg / cm and The temperature passed through the layered catalyst of the composition specified in Example 1. The reacted gas at the outlet and the reactor has the following characteristics: Volumetric flow rate, 5600 Composition, wt.%: H, 248.58 СО8.45 COj17.45, 66 , 53 SNeON2,23 SNZOSIS 18.48. . 3.32 Temperature, ° C 270 Get 1250 methyl alcohol and 10360 DME, which corresponds to a conversion of carbon monoxide of 67%. Let us accept 3. They work under the conditions of example 2, but with the following characteristic of the initial mixture obtained by partial oxidation of heavy O.J oils: Volume velocity GTH11, -1T / -3 100,000 flows. wt.%: Composition, Hct CO CO2; Molar ratio of CO and H 1.16 Temperature, C250 At the reactor discharge, the gaseous product has the following characteristics: Volumetric flow rate nm h50350 Composition, wt%: Na14.05 SO29.97 SOch 27.30 . СН, ОН0.91 СНзОСНз24,20 СН40.54 NJ 2.62, 0.41 Temperature, ° С270 In the end, AHjOH 460-nm / h 12150 HMV4 DME is obtained. CO conversion is 77%. PRI me R 4. The catalyst is obtained by thoroughly mixing the powders of the catalyst Cu, Zn, Cr at a ratio of 82: 16: 4 and alumina powders at a weight ratio of 1: 1. The catalyst thus obtained is pelletized in the form of particles with a diameter of 6 mm. 5 m of such a catalyst is introduced into the reactor, and then a gas mixture is fed at a percentage ratio of Hg: CO: COg 49: 49: 2, a molar ratio of CO-HQ to 1.00 and a flow rate of 100,000. The temperature in the reactor is 250 ° C and the pressure is 100 kg / cm. The effluent from the reactor consists of Hrj, GO, CO-i, CH4, CH, OH, ,, CHj with a CO conversion of 27%. The DME selectivity is 64%, methanol 7.8%, 1% each, and CO (27.2%. Then the reaction mixture is distilled to obtain pure DME. Example 5. The catalyst and gas mixture are used with characteristics indicated in Example 4. At a process temperature and a pressure of 100 kg / cm, the conversion of CO is 35%, the selectivity for DME is 65%, for methanol — 2.1%, for CH4 — 1.5% and for CO -i - 31.4%. Example 6. The catalyst and gas mixture flow rates described in Example 4 are used at a temperature of 300 ° C and a pressure of 150 kg / cm. The conversion of CO is 40% with a selectivity of 66%, and meta zero - 2.2%, on CH - If8%, on CO2 - 30% Claim 1. A method of producing dimethyl ether by converting a mixture of gases CO, Go CO at a temperature of 280-400 C and a pressure of 100-150 atm in the presence of oxide zinc chromium-containing catalyst and alumina, characterized in that, in order to pay attention to the selectivity of the process, the latter is carried out at a molar ratio of carbon monoxide to hydrogen from 0.56 to 1.16 per zinc-chromium-copper-aluminum catalyst. 2. Method POP.1, characterized in that a catalyst is used, made in the form of alternating layers of a zinc-chromium-copper catalyst and alumina at a weight ratio of 1: 1. 3. The method according to claim 1, about t l and h a and y and with the fact that use a catalyst containing components, in the form of a mechanical mixture. Sources of information accepted,. Attention in the examination 1, J.Schmidt, Das Kohlenoxid:, Leipzig, Academische verlagsgeselleschaff, 1950, s. 189-220 (prototype).