CN115611696A - A low-temperature, low-power microwave treatment process for low-carbon alcohols - Google Patents

Abstract

The invention relates to the field of low-carbon alcohol conversion, in particular to a low-temperature, low-power microwave treatment process for low-carbon alcohol compounds. Specifically include: mixing low-carbon alcohol compounds and wave-absorbing substances, and reacting under microwave conditions to produce hydrogen, carbon monoxide, carbon dioxide, and low-carbon hydrocarbon compounds; or, mixing low-carbon alcohol compounds, wave-absorbing substances and Catalysts are mixed and reacted under microwave conditions to produce hydrogen, carbon monoxide, carbon dioxide and low-carbon hydrocarbon compounds; wherein, the mass ratio of low-carbon alcohol compounds to wave-absorbing substances is (0.01-5):1. The invention can effectively improve the conversion rate of low-carbon alcohol compounds and increase the hydrogen content in products by optimizing the reaction process and conditions. At the same time, the process can greatly reduce the reaction temperature, has high heating rate and reaction rate, low energy consumption, better economic benefits, and has good industrial application prospects.

Description

A low-temperature, low-power microwave treatment process for low-carbon alcohols

technical field

The invention relates to the field of low-carbon alcohol conversion, in particular to a low-carbon, low-power microwave treatment process for low-carbon alcohol compounds.

Background technique

At present, the conversion of low-carbon alcohols with low economic and energy benefits to olefins and hydrogen energy with higher energy benefits and more environmental friendliness is a research hotspot. For example, methanol is an important strategic reserve energy because of its low-carbon, hydrogen-rich, and easy storage and transportation. Whether it is converted into ethylene and propylene with high economic benefits through molecular sieve catalysts, or methanol decomposition through metal catalysts, methanol fractions Oxidation and steam reforming of methanol into hydrogen, carbon monoxide and carbon dioxide all have high economic value and social benefits.

Recent studies have shown that methanol reforming is an attractive option for hydrogen production because methanol does not contain sulfur, has a high volumetric energy density, has a hydrogen-to-carbon ratio of 4:1, and is biodegradable. Compared with other alcohols, methanol is preferred because it does not contain C-C bonds, and the hydrogen extraction temperature is much lower, about 200-300°C, while the conversion temperature of ethanol and methane is much higher, 400°C and 500°C respectively .

At present, under traditional conditions, the reaction conditions for olefin conversion of low-carbon alcohols are still relatively harsh. For example, the optimum temperature for methanol conversion still needs to be greater than 300°C to obtain better product selectivity; at the same time, high temperature not only greatly increases the requirements for equipment and catalysts, but the high energy consumption required for the reaction also brings huge economic impacts. pressure. For example, CN106008128 A discloses a reaction regeneration system and method for methanol to propylene, which uses a single-stage adiabatic fixed-bed reactor to prepare olefins from methanol, the inlet pressure of the reactor is 0.15-1 MPa, and the reaction temperature is 350-450 ° C; CN105949021 Disclosed in A is a system and method for preparing propylene by catalytic dehydration of methanol, which adopts a fluidized bed reactor, the operating pressure of the dehydration reactor and the catalyst regenerator is 0.1-1MPa, the dehydration reaction temperature is 400-500°C, and the catalyst is regenerated The temperature is 450-650°C; CN 105060247 A discloses a start-up system for starting a reforming hydrogen production unit, which reports the steam reforming reaction of methanol, and the reforming hydrogen production unit includes a reformer shell and The combustion chamber and reforming chamber located in the housing of the reforming hydrogen production unit generally require 350-409°C in the reforming chamber and 405-570°C in the combustion chamber, so that the reforming hydrogen production unit can work normally.

For the relatively harsh conversion conditions of low-carbon alcohols, the existing technology still focuses on the optimization of fluidized bed and fixed bed reactors, the adjustment of temperature and the exploration of new catalysts. No one has tried microwave conditions. Research on the transformation of low carbon alcohols.

Contents of the invention

The invention provides a low-temperature, low-power microwave treatment process for low-carbon alcohol compounds, which is used to solve the defect of high-temperature energy consumption in the conversion reaction of low-carbon alcohols in the prior art, and realize a fast temperature rise, low energy consumption, and high conversion The conversion treatment process of low-carbon alcohol compounds with high efficiency and high content of energy substances in the product.

The conversion treatment process of low-carbon alcohol compounds provided by the present invention is to mix low-carbon alcohol compounds with wave-absorbing substances and react under microwave conditions to produce hydrogen, carbon monoxide, carbon dioxide and low-carbon hydrocarbon compounds; or ,

Mixing the low-carbon alcohol compound, the wave-absorbing substance and the catalyst, and reacting under microwave conditions to produce hydrogen, carbon monoxide, carbon dioxide and low-carbon hydrocarbon compounds;

Wherein, the mass ratio of the low-carbon alcohol compound to the absorbing substance is (0.01-5):1.

The present invention finds that under the high energy density of microwaves, the stability of chemical bonds will be greatly affected, and the high-efficiency conversion of low-carbon alcohol compounds at a relatively low temperature is promoted, thereby effectively improving the conversion rate of low-carbon alcohol compounds. Subsequent further studies have found that when the ratio of the low-carbon alcohol compound and the absorbing substance is the above ratio, the hydrogen content in the product is significantly increased, and the carbon dioxide content in the product can be effectively reduced, thereby increasing the product value.

Preferably, the mass space velocity of the low-carbon alcohol compound feed is 0.01˜5 h ⁻¹ .

More preferably, the mass space velocity of the low-carbon alcohol compound feed is 0.01˜2 h ⁻¹ .

Preferably, the low-carbon alcohol compound, the absorbing substance and the catalyst are mixed under microwave conditions.

Preferably, the absorbing material is selected from carbon nanotubes, graphite, activated carbon, magnesium oxide, iron oxide, zinc oxide, calcium oxide, manganese oxide, phosphorus pentoxide, nickel oxide, titanium dioxide, aluminum oxide, molybdenum oxide, sulfide One or more of molybdenum, molybdenum carbide, copper sulfide, silicon oxide.

More preferably, the absorbing material is selected from magnesium oxide, iron oxide, zinc oxide, calcium oxide, manganese oxide, nickel oxide, aluminum oxide, molybdenum oxide, molybdenum carbide, silicon oxide and loaded iron, nickel, copper, cobalt, One or more of carbon nanotubes, graphite and activated carbon of one or more elements of platinum and gold.

The present invention finds that the above-mentioned microwave-absorbing material, that is, the microwave absorbing agent, not only has a better microwave-absorbing effect, but also plays a certain catalytic role, which is more conducive to the efficient conversion of low-carbon alcohol compounds.

More preferably, the absorbing material is selected from one or more of carbon nanotubes, graphite and activated carbon.

Preferably, the catalyst is molecular sieve, zirconia, cerium oxide and molecular sieve loaded with one or more elements in iron, nickel, copper, cobalt, platinum and gold, aluminum oxide, zinc oxide, zirconia, iron oxide and oxide One or more of cerium.

During the reaction process, the catalyst is prone to carbon deposition and deactivation, but the present invention unexpectedly finds that the existence of the above catalyst carbon deposition can simultaneously improve the wave-absorbing efficiency of the reaction system.

As a preference, when the absorbing material is continuously used for more than 24 hours, it is calcined or ground; more preferably, it is calcined in the air above 300°C for 1 to 3 hours; it can promote its effective activation, thereby performing multiple time use.

As preferably, when the reaction system contains the molecular sieve, aluminum oxide, zinc oxide, zirconium oxide and cerium oxide, carbon nanotube, graphite, active carbon in the molecular sieve, aluminum oxide, zinc oxide, zirconium oxide and cerium oxide, carbon nanotube, graphite, active carbon of loading 1～15wt% in iron, nickel and cobalt, When one or more are used, the content of hydrogen and carbon monoxide in the product increases, while the content of carbon dioxide decreases, which further improves the value of the product.

More preferably, the reaction system contains one of molecular sieves, aluminum oxide, zinc oxide, zirconium oxide and cerium oxide, carbon nanotubes, graphite, and activated carbon loaded with 5 to 10 wt% of one or more elements in iron, nickel, and cobalt. One or more, the effect is better.

The present invention finds that the catalyst can effectively reduce the content of carbon dioxide in the product, increase the content of energy substances in the product, and further increase the value of the product.

Preferably, when the reaction system is a low-carbon alcohol compound, a wave-absorbing substance and a catalyst, the mass ratio of the catalyst to the wave-absorbing substance is (1:10)˜(15:1).

As a preferred embodiment of the present invention, the conversion treatment process of the low-carbon alcohols is carried out under the conditions of microwave, oxygen-free, normal pressure, and 160-230°C.

Preferably, the low-carbon alcohol compounds include all monohydric and polyhydric alcohols with 1-4 carbon atoms.

Preferably, during the reaction, the low-carbon alcohol compound is mixed with other raw materials in a gaseous state.

Preferably, during the reaction, the low-carbon alcohols are heated and gasified before being fed.

More preferably, during the reaction process, the liquid low-carbon alcohol compound is converted into a gaseous state by bubbling with an inert gas and then fed.

Preferably, the microwave reaction device used in the conversion treatment process of the low-carbon alcohol compound includes: a housing, an infrared temperature measuring device, an input power detector, a reflected power detector, a microwave generator, an integrated control system and an automatic protection unit Wherein, the input power, temperature and reflected power are monitored in real time through the integrated control system, and the input power is regulated according to the temperature, and the startup of the automatic protection unit is controlled according to the reflected power; when the reflected power is greater than 50% of the input power, the automatic protection unit start, the reactor stops working; the microwave generator is a solid-state source.

Preferably, the housing of the microwave reaction device is a stainless steel housing.

Preferably, the microwave frequency is 2.45GHz or 915MHz; more preferably, the microwave frequency is 2.45GHz.

Preferably, the heating mode of the microwave is single-mode or multi-mode.

Based on the above-mentioned technical scheme, the beneficial effects of the present invention are:

A low-temperature, low-power microwave treatment process for low-carbon alcohol compounds provided by the present invention can effectively improve the conversion rate of low-carbon alcohol compounds by optimizing the reaction process and conditions, and at the same time significantly increase the hydrogen content in the product. Thereby increasing the value of the product. At the same time, compared with the traditional process, the process can greatly reduce the reaction temperature, and has a higher heating rate and reaction rate, lower energy consumption, and lower requirements for equipment and absorbing materials, which is conducive to cost saving and economic benefits. Well, it has good industrial application prospects.

Description of drawings

In order to more clearly illustrate the present invention or the technical solutions in the prior art, the accompanying drawings that need to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings in the following description are the present invention. For some embodiments of the invention, those skilled in the art can also obtain other drawings based on these drawings without creative effort.

Fig. 1 is the process flow sheet of microwave treatment process of the present invention;

Fig. 2 is a schematic diagram of the production system of the present invention, wherein the arrow represents the gas flow direction, and the cross symbol represents the wave-absorbing substance; when the reaction system contains a catalyst, the cross-shaped symbol represents the wave-absorbing substance and the catalyst;

Reference signs: 1-inert gas generating device, 2-flow meter, 3-three-way valve, 4-bubbler, 5-microwave generator, 6-product gas collection device, 7-gas chromatography device.

detailed description

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention , but not all examples. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

In the present invention, when the wave-absorbing material is used continuously for more than 24 hours, those skilled in the art can calcinate it in the air above 300°C for 1-3 hours according to the actual situation, so as to activate it effectively, and then use it multiple times. , the specific process flow shown in Figure 1.

In a specific embodiment, the present invention also provides a production system for realizing the above method of microwave treatment of methanol conversion, the schematic diagram of which is specifically shown in Figure 2, including: an inert gas generator 1, a flow meter 2, a three-way valve 3, and a bubbler 4 , microwave generator 5, product gas collection device 6 and gas chromatography device 7. Wherein, the outlet of the inert gas generating device 1 is connected to the first inlet of the three-way valve 3, the flow meter 2 is arranged on the connection path between the first inlet of the three-way valve 3 and the outlet of the inert gas generating device 1, and the bubbler 4 is connected to the second inlet of the three-way valve 3, the outlet of the three-way valve is connected to the gas inlet of the microwave generator 5, and the gas outlet of the microwave generator 5 is respectively connected to the product gas collection device 6 and the gas chromatography device 7.

The gas chromatographic detection conditions are: GC-7820 gas chromatograph TCD+FID online detection, TCD temperature is 70°C, FID is 70°C, keep for 16min, 10°C/min heating rate to 210°C, keep for 15min.

Example 1

This embodiment provides a method for microwave treatment of methanol conversion, the specific reaction steps are as follows:

1. Add carbon nanotubes into the microwave reactor, adjust the input power to 55W; and use the bubbling method to use argon to bring methanol into the microwave reactor at a mass space velocity of 1h ^-1 , the amount of methanol and carbon nanotubes The mass ratio was 1:1, and the reaction was carried out at 160°C. After 1 h, gas chromatography was used to detect gas product components in real time.

2. Add a mixture of carbon nanotubes and molecular sieve H-ZSM5 (a silicon-aluminum ratio of 21) in a microwave reactor with a mass ratio of 1:1, and adjust the input power to 60W; Carry it into a microwave reactor at a mass space velocity of 1 h ^-1 , the mass ratio of methanol to carbon nanotubes is 1:1, and react at 160°C. After 1 h, gas chromatography was used to detect gas product components in real time.

3. Add zinc oxide into the microwave reactor, set the input power to 60W; use argon gas to bring methanol with a mass space velocity of ^0.01h into the reactor by bubbling method, and the mass ratio of methanol to zinc oxide is 0.01:1, react at 160°C. After 1 h, gas chromatography was used to detect gas product components in real time.

4. Add a mixture of zinc oxide and molecular sieve H-ZSM5 (the ratio of silicon to aluminum is 21) in a microwave reactor with a mass ratio of 5:1, and adjust the input power to 60W; The mass space velocity is 0.07h ^-1 into the microwave reactor, the mass ratio of methanol to zinc oxide is 0.07:1, and the reaction is carried out at 160°C. After 1 h, gas chromatography was used to detect gas product components in real time.

5. Add carbon nanotubes into the microwave reactor, adjust the input power to 55W; and use the bubbling method to use argon to bring methanol into the microwave reactor at a mass space velocity of 1h ^-1 , methanol and 5wt%Ni The mass ratio of carbon nanotubes was 1:1, and the reaction was carried out at 160 °C. After 1 h, gas chromatography was used to detect gas product components in real time.

Concrete product composition is as shown in table 1:

Table 1

Example 2

A method for microwave treatment of ethanol conversion, the specific reaction process is as follows:

1. Add carbon nanotubes into the microwave reactor, adjust the input power to 55W; and use the bubbling method to use argon to bring ethanol into the microwave reactor at a mass space velocity of 0.3h ^-1 , ethanol and carbon nanotubes The mass ratio was 0.3:1, and the reaction was carried out at 160°C. After 1 h, gas chromatography was used to detect gas product components in real time.

2. Add a mixture of carbon nanotubes and molecular sieve H-ZSM5 (a silicon-aluminum ratio of 21) in a microwave reactor with a mass ratio of 1:1, and adjust the input power to 70W; Carry it into a microwave reactor at a mass space velocity of 0.3h ^-1 , the mass ratio of ethanol to carbon nanotubes is 0.3:1, and react at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

3. Add zinc oxide into the microwave reactor, set the input power to 70W; use argon gas to bring ethanol with a mass space velocity of ^0.05h into the reactor, and the mass ratio of ethanol to zinc oxide is 0.05:1, react at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

4. Add a mixture of zinc oxide and molecular sieve H-ZSM5 (silicon-aluminum ratio is 21) with a mass ratio of 5:1 in the microwave reactor, and adjust the input power to 70W; The mass space velocity is 0.05h ^-1 into the microwave reactor, the mass ratio of ethanol to zinc oxide is 0.05:1, and the reaction is carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

Concrete product composition is as shown in table 2:

Table 2

Example 3

A method for microwave treatment of n-propanol conversion, the specific reaction process is as follows:

1. Add carbon nanotubes into the microwave reactor, adjust the input power to 70W; and use the bubbling method to use argon to bring n-propanol into the microwave reactor at a mass space velocity of 0.1h ^-1 , n-propanol The mass ratio to carbon nanotubes is 0.1:1, and the reaction is carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

2. Add a mixture of carbon nanotubes and molecular sieve H-ZSM5 (the ratio of silicon to aluminum is 21) in the microwave reactor with a mass ratio of 1:1, and adjust the input power to 70W; Propanol was brought into the microwave reactor at a mass space velocity of 0.1h ^-1 , the mass ratio of n-propanol to carbon nanotubes was 0.1:1, and the reaction was carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

3. Add zinc oxide into the microwave reactor, set the input power to 70W; use argon gas to bring n-propanol with a mass space velocity of 0.02h ^-1 into the reactor by bubbling method, n-propanol and zinc oxide The mass ratio was 0.02:1, and the reaction was carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

4. Add a mixture of zinc oxide and molecular sieve H-ZSM5 (the ratio of silicon to aluminum is 21) in the microwave reactor with a mass ratio of 5:1, and adjust the input power to 70W; The alcohol is brought into the microwave reactor at a mass space velocity of 0.02h ^-1 , the mass ratio of n-propanol to zinc oxide is 0.02:1, and the reaction is carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

Concrete product composition is as shown in table 3:

table 3

Example 4

A method for microwave treatment of isopropanol conversion, the concrete reaction process is as follows:

1. Add carbon nanotubes into the microwave reactor, adjust the input power to 70W; and use the bubbling method to use argon to bring n-propanol into the microwave reactor at a mass space velocity of 0.5h ^-1 , isopropanol The mass ratio to carbon nanotubes is 0.5:1, and the reaction is carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

2. Add a mixture of carbon nanotubes and molecular sieve H-ZSM5 (the ratio of silicon to aluminum is 21) in the microwave reactor with a mass ratio of 1:1, and adjust the input power to 70W; Propanol was brought into the microwave reactor at a mass space velocity of 0.5h ^-1 , the mass ratio of isopropanol to carbon nanotubes was 0.5:1, and the reaction was carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

3. Add zinc oxide into the microwave reactor, set the input power to 70W; use argon gas to bring n-propanol with a mass space velocity of 0.1h ^-1 into the reactor by bubbling method, isopropanol and zinc oxide The mass ratio was 0.1:1, and the reaction was carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

4. Add a mixture of zinc oxide and molecular sieve H-ZSM5 (the ratio of silicon to aluminum is 21) in the microwave reactor with a mass ratio of 5:1, and adjust the input power to 70W; The alcohol is brought into the microwave reactor at a mass space velocity of 0.1h ^-1 , the mass ratio of isopropanol to zinc oxide is 0.1:1, and the reaction is carried out at 180°C. After 1 h, gas chromatography was used to detect gas product components in real time.

Concrete product composition is as shown in table 4:

Table 4

Comparative example 1

The process conditions of this comparative example are the same as those of Example 1, except that the mass ratio of methanol to carbon nanotubes is 5.8:1 and 9:1, and the mass ratio of carbon nanotubes to H-ZSM5(21) is 1:1. Concrete product composition is as shown in table 5:

table 5

It can be seen from Table 5 that although the increase of the mass ratio can also achieve a higher conversion rate, the generation of hydrogen is inhibited, the content of hydrogen in the product gas is significantly reduced, the content of carbon dioxide is significantly increased, and most of the methanol is converted into carbon deposits On the surface of the catalyst and absorbing material, it is not conducive to the reaction.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A conversion treatment process for low-carbon alcohol compounds, characterized in that low-carbon alcohol compounds are mixed with wave-absorbing substances, and reacted under microwave conditions to produce hydrogen, carbon monoxide, carbon dioxide and low-carbon hydrocarbons compound; or, Mixing the low-carbon alcohol compound, the wave-absorbing substance and the catalyst, and reacting under microwave conditions to produce hydrogen, carbon monoxide, carbon dioxide and low-carbon hydrocarbon compounds; Wherein, the mass ratio of the low-carbon alcohol compound to the absorbing substance is (0.01-5):1. 2 . The conversion treatment process of low-carbon alcohol compounds according to claim 1 , characterized in that, the mass space velocity of the low-carbon alcohol compound feed is 0.01˜5 h ⁻¹ . 3. The conversion treatment process of low-carbon alcohol compounds according to claim 1 or 2, wherein the absorbing material is selected from carbon nanotubes, graphite, activated carbon, magnesium oxide, iron oxide, zinc oxide, oxide One or more of calcium, manganese oxide, phosphorus pentoxide, nickel oxide, titanium dioxide, aluminum oxide, molybdenum oxide, molybdenum sulfide, molybdenum carbide, copper sulfide, and silicon oxide. 4. The conversion treatment process of low-carbon alcohol compounds according to any one of claims 1 to 3, wherein the absorbing material is selected from the group consisting of magnesium oxide, iron oxide, zinc oxide, calcium oxide, manganese oxide, Nickel oxide, aluminum oxide, molybdenum oxide, molybdenum carbide, silicon oxide, and one or more of carbon nanotubes, graphite, and activated carbon loaded with one or more elements of iron, nickel, copper, cobalt, platinum, and gold. 5. The conversion treatment process of low-carbon alcohol compounds according to any one of claims 1 to 4, wherein the catalyst is molecular sieve, zirconia, cerium oxide and loaded iron, nickel, copper, cobalt, platinum One or more of molecular sieves, aluminum oxide, zinc oxide, zirconium oxide, iron oxide, and cerium oxide of one or more elements in gold. 6. The conversion treatment process of low-carbon alcohol compounds according to any one of claims 1 to 5, characterized in that, when the reaction system contains one or more of iron, nickel and cobalt loaded with 1 to 15 wt% When one or more of molecular sieve, aluminum oxide, zinc oxide, zirconium oxide and cerium oxide, carbon nanotubes, graphite, and activated carbon are used, the content of hydrogen and carbon monoxide in the product increases, while the content of carbon dioxide decreases. 7. The conversion treatment process of low-carbon alcohol compounds according to any one of claims 1 to 6, characterized in that, when the reaction system is low-carbon alcohol compounds, wave-absorbing substances and catalysts, the catalyst and the The mass ratio of the absorbing material is (1:10)-(15:1). 8. The conversion treatment process of low-carbon alcohol compounds according to any one of claims 1-7, characterized in that the reaction is carried out under the conditions of microwave, oxygen-free, normal pressure and 160-230°C. 9. The conversion treatment process of low-carbon alcohol compounds according to any one of claims 1-8, characterized in that the low-carbon alcohol compounds include all monohydric and polyhydric alcohols with 1-4 carbon atoms. 10. The conversion treatment process of low-carbon alcohol compounds according to any one of claims 1-9, characterized in that, during the reaction process, the low-carbon alcohol compounds are mixed with other raw materials in gaseous form.

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