CN115959970A

CN115959970A - Zero-carbon-emission coal-to-methanol system and method for preparing methanol from coal

Info

Publication number: CN115959970A
Application number: CN202111182369.5A
Authority: CN
Inventors: 毛燕东; 野田; 王俊美
Original assignee: ENN Science and Technology Development Co Ltd
Current assignee: ENN Science and Technology Development Co Ltd
Priority date: 2021-10-11
Filing date: 2021-10-11
Publication date: 2023-04-14

Abstract

The invention relates to a zero-carbon-emission coal-to-methanol system and a method for preparing methanol from coal, wherein the zero-carbon-emission coal-to-methanol system comprises a coal gasification device, a raw gas purification and cooling device, an acid gas separation device, a carbon dioxide hydrogenation methanol synthesis device and a synthesis gas methanol synthesis device; the coal gasification device is used for carrying out gasification reaction on the coal feed to generate crude coal gas; the raw gas purification and cooling device is used for cooling and purifying raw gas; the acid gas separation device is used for separating the crude gas after cooling and purifying treatment so as to separate out carbon dioxide, synthesis gas and hydrogen sulfide; the carbon dioxide hydrogenation methanol synthesis device is used for synthesizing carbon dioxide and hydrogen to obtain methanol; the synthesis gas methanol synthesis device is used for synthesizing synthesis gas to obtain methanol, carbon utilization efficiency of coal is improved while carbon dioxide emission reduction is realized, methanol productivity is increased while coal consumption is not increased, and considerable economic benefit is brought.

Description

Zero-carbon-emission coal-to-methanol system and method for preparing methanol from coal

Technical Field

The disclosure relates to the technical field of coal chemical industry, in particular to a zero-carbon-emission coal-to-methanol system and a method for preparing methanol from coal.

Background

At present, coal is still the most abundant fossil energy in China among the energy proportions. At the present stage and for a long time in the future, the main energy position of coal in China is still difficult to change. The clean and efficient utilization of coal can promote the green transformation development of energy in China and simultaneously has immeasurable effect on reducing carbon emission in China.

The coal chemical industry is an important channel for realizing clean and efficient utilization of coal. Various chemical products can be obtained through the coal chemical industry, wherein the maximum productivity is methanol. At present, methanol is mostly used as a standard raw material in the industries of energy, fuel, chemical industry and the like, the capacity of the methanol reaches 9100 million tons in China in 2020, mainly comes from methanol prepared from coal (accounting for 76%), and the emission of carbon dioxide is large in the process of preparing the methanol from the coal. At present, the existing coal-to-methanol process has large carbon emission, high water consumption, large influence of coal price on methanol cost, and greatly limited market profit space along with the rising of coal price.

Therefore, how to realize the emission reduction of carbon dioxide in the process of preparing methanol from coal and increase the methanol capacity without increasing the coal consumption becomes an urgent problem to be solved.

Disclosure of Invention

In order to solve the technical problems or at least partially solve the technical problems, the present disclosure provides a zero-carbon-emission coal-to-methanol system and a coal-to-methanol method.

In a first aspect, the present disclosure provides a zero-carbon-emission coal-to-methanol system, which includes a coal gasification device, a raw gas purification and cooling device, an acid gas separation device, a carbon dioxide hydrogenation methanol synthesis device, and a synthesis gas methanol synthesis device;

the coal gasification device is used for carrying out gasification reaction on the coal feed to generate crude coal gas; the raw gas purification and cooling device is communicated with a raw gas outlet of the coal gasification device and is used for cooling and purifying the raw gas;

the acid gas separation device is communicated with the raw gas purification and cooling device and is used for separating the raw gas after cooling and purification treatment so as to separate carbon dioxide, synthesis gas and hydrogen sulfide; the acid gas separation device is provided with a carbon dioxide outlet for discharging the carbon dioxide, a synthesis gas outlet for discharging the synthesis gas and a hydrogen sulfide outlet for discharging the hydrogen sulfide;

the carbon dioxide hydrogenation methanol synthesis device is provided with a carbon dioxide inlet communicated with the carbon dioxide outlet and a hydrogen inlet allowing hydrogen to enter, and is used for carrying out synthesis treatment on the carbon dioxide and the hydrogen to obtain methanol; the synthesis gas methanol synthesis device is communicated with the synthesis gas outlet and is used for carrying out synthesis treatment on the synthesis gas to obtain methanol.

Optionally, the carbon dioxide-hydrogenated methanol synthesis apparatus includes a carbon dioxide-hydrogenated methanol synthesis module and a first cooling separation module;

the carbon dioxide hydrogenation methanol synthesis module is provided with a carbon dioxide inlet and a hydrogen inlet and is used for carrying out synthesis treatment on the carbon dioxide and the hydrogen to obtain a first crude product containing methanol; the first cooling separation module is used for cooling separation of the first crude product to obtain the methanol.

Optionally, the synthesis gas methanol synthesis device comprises a synthesis gas methanol synthesis module and a second cooling separation module;

the synthesis gas methanol synthesis module is used for carrying out synthesis treatment on the synthesis gas to obtain a second crude product containing methanol; and the second cooling separation module is used for cooling separation of the second crude product to obtain the methanol.

Optionally, the coal-to-methanol system further comprises a methanol purification device;

the methanol purification device is provided with a methanol inlet which is respectively communicated with a methanol outlet of the carbon dioxide hydrogenation methanol synthesis device and a methanol outlet of the synthesis gas methanol synthesis device; the methanol purification device is used for purifying the methanol to obtain refined alcohol.

Optionally, the coal-to-methanol system further comprises a sulfur recovery device;

and the sulfur recovery device is communicated with the hydrogen sulfide outlet and is used for recovering the hydrogen sulfide to obtain a sulfur product.

Optionally, the coal-to-methanol system further comprises a mixing gas distribution supercharging device;

the carbon dioxide hydrogenation methanol synthesis device is provided with a first discharge port for discharging unconverted raw material gas and a circulating gas inlet, the synthesis gas methanol synthesis device is provided with a second discharge port for discharging unconverted raw material gas, and the first discharge port and the second discharge port are respectively communicated with the gas inlet of the mixed gas distribution pressurizing device;

the mixed gas distribution supercharging device is used for mixing and supercharging the hydrogen and the unconverted raw material gas entering from the gas inlet to obtain a circulating gas, and the circulating gas enters the carbon dioxide hydrogenation methanol synthesis device from the circulating gas inlet.

Optionally, the coal-to-methanol system further comprises a water electrolysis hydrogen production device;

the hydrogen outlet of the water electrolysis hydrogen production device is at least communicated with the hydrogen inlet and the synthesis gas methanol synthesis device so as to provide hydrogen for at least the carbon dioxide hydrogenation methanol synthesis device and the synthesis gas methanol synthesis device;

and an oxygen outlet of the water electrolysis hydrogen production device is communicated with the coal gasification device so as to provide oxygen for the coal gasification device.

Optionally, the coal-to-methanol system further includes a renewable energy power generation device and an electric boiler device;

the renewable energy power generation device is at least used for supplying power to the electric boiler device and the water electrolysis hydrogen production device; and a steam outlet of the electric boiler device is communicated with the coal gasification device so as to provide steam for the coal gasification device.

In a second aspect, the present disclosure provides a method for coal-to-methanol using the zero-carbon-emission coal-to-methanol system as described above, the method comprising:

introducing a coal material into a coal gasification device, and carrying out gasification reaction on the coal material in the coal gasification device to generate crude coal gas;

introducing the crude gas into a crude gas purification cooling device for cooling and purification treatment;

introducing the raw gas subjected to cooling and purifying treatment into an acid gas separation device so as to enable the acid gas separation device to separate the raw gas subjected to cooling and purifying treatment to separate carbon dioxide, hydrogen sulfide and synthesis gas;

introducing hydrogen and the separated carbon dioxide into a carbon dioxide hydrogenation methanol synthesis device so that the carbon dioxide hydrogenation methanol synthesis device performs synthesis treatment on the hydrogen and the carbon dioxide to obtain methanol;

and introducing the separated synthesis gas into a synthesis gas methanol synthesis device so that the synthesis gas methanol synthesis device performs synthesis treatment on the synthesis gas to obtain methanol.

Optionally, the synthesis reaction pressure in the carbon dioxide hydrogenation methanol synthesis device is 2.5-5MPa, the reaction temperature is 150-250 ℃, the hydrogen-carbon ratio is 2.9-3.1, the keeping airspeed is 3000-10000 ml/(g cat h), the single-pass conversion rate of carbon dioxide is more than 20%, and the selectivity of methanol is more than 80%.

Optionally, the step of introducing the hydrogen and the separated carbon dioxide into a carbon dioxide-hydrogenated methanol synthesis apparatus to enable the carbon dioxide-hydrogenated methanol synthesis apparatus to perform synthesis processing on the hydrogen and the carbon dioxide to obtain methanol includes:

introducing hydrogen and the separated carbon dioxide into a carbon dioxide hydrogenation methanol synthesis module so that the carbon dioxide hydrogenation methanol synthesis module performs synthesis treatment on the hydrogen and the carbon dioxide to obtain a first crude product containing methanol; wherein the carbon dioxide hydromethanol synthesis module has a catalyst therein, the catalyst comprising at least one of a copper-based catalyst and a molybdenum-based catalyst;

and introducing the first crude product into a first cooling separation module so that the first cooling separation module cools and separates the first crude product to obtain the methanol.

Optionally, the step of introducing the separated synthesis gas into a synthesis gas methanol synthesis device, so that the synthesis gas methanol synthesis device performs synthesis treatment on the synthesis gas to obtain methanol includes:

introducing the separated synthesis gas into a synthesis gas methanol synthesis module so that the synthesis gas methanol synthesis module carries out synthesis treatment on the synthesis gas to obtain a second crude product containing methanol;

and introducing the second crude product into a second cooling separation module so that the second cooling separation module cools and separates the second crude product to obtain the methanol.

Optionally, the method further includes:

introducing the methanol into a methanol purification device so that the methanol purification device purifies the methanol to obtain refined alcohol;

carrying out conversion utilization on the refined alcohol to obtain a target product; wherein the target product comprises at least one of an olefin, an aromatic hydrocarbon, or hydrogen.

Optionally, the method further includes:

introducing an unconverted raw material gas discharged by the carbon dioxide hydrogenation methanol synthesis device and an unconverted raw material gas discharged by the synthesis gas methanol synthesis device into a mixed gas distribution and pressurization device, and introducing hydrogen into the mixed gas distribution and pressurization device, so that the mixed gas distribution and pressurization device mixes and pressurizes the unconverted raw material gas and the hydrogen to obtain a circulating gas;

and introducing the circulating gas into the carbon dioxide hydrogenation methanol synthesis device.

Optionally, the method further includes:

at least part of hydrogen generated by a water electrolysis hydrogen production device is introduced into the carbon dioxide hydrogenation methanol synthesis device and the synthesis gas methanol synthesis device so as to provide hydrogen for the carbon dioxide hydrogenation methanol synthesis device and the synthesis gas methanol synthesis device;

introducing oxygen generated by the water electrolysis hydrogen production device into the coal gasification device so as to provide oxygen for the coal gasification device;

introducing steam generated by an electric boiler device into the coal gasification device so as to provide the steam for the coal gasification device; wherein power is supplied to the electrolyzed water hydrogen production device and the electric boiler device by a renewable energy power generation device.

Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:

according to the zero-carbon-emission coal-to-methanol system and the method for preparing methanol from coal, the raw gas generated by the coal gasification device is cooled and purified by the raw gas purification and cooling device, and the raw gas treated by the cooling and purifying device is cooled and purified by the acid gas separation device so as to separate carbon dioxide, synthesis gas and hydrogen sulfide; the synthesis gas methanol synthesis device is used for synthesizing the separated synthesis gas to obtain methanol, and the carbon dioxide hydrogenation methanol synthesis device is used for synthesizing the separated carbon dioxide to obtain methanol, so that the carbon dioxide emission reduction is realized, the utilization efficiency of carbon in coal is improved, the methanol productivity is increased without increasing the coal consumption, and considerable economic benefit is brought.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present disclosure, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

FIG. 1 is a zero carbon emissions coal to methanol system according to an embodiment of the present disclosure;

fig. 2 is a schematic flow diagram of a method for producing methanol from coal according to an embodiment of the present disclosure.

Wherein, 1, a coal gasification device; 10. a coal pretreatment device; 11. a raw gas outlet; 2. a raw gas purification and cooling device; 3. an acid gas separation unit; 31. a carbon dioxide outlet; 32. a syngas outlet, 33, a hydrogen sulfide outlet; 30. a sulfur recovery unit; 4. a carbon dioxide hydrogenation methanol synthesis device; 41. a carbon dioxide hydrogenation methanol synthesis module; 411. a carbon dioxide inlet; 412. A hydrogen inlet; 413. a recycle gas inlet; 42. a first cooling separation module; 421. a methanol outlet; 43. a first heat recovery module; 5. a synthesis gas methanol synthesis unit; 51. a synthesis gas methanol synthesis module; 52. a second cooling separation module; 521. a methanol outlet; 53. a second heat recovery module; 6. a methanol purification device; 61. a methanol tank zone; 7. a hybrid distribution supercharging device; 8. A hydrogen production device by water electrolysis; 81. a hydrogen outlet; 82. an oxygen outlet; 80. a green hydrogen distribution device; 9. a renewable energy power generation device; 90. an electric boiler device.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, aspects of the present disclosure will be further described below. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced otherwise than as described herein; it is to be understood that the embodiments disclosed in the specification are only a few embodiments of the present disclosure, and not all embodiments.

Referring to fig. 1, the present embodiment provides a zero-carbon-emission coal-to-methanol system, including: a coal gasification device 1, a raw gas purification and cooling device 2, an acid gas separation device 3, a carbon dioxide hydrogenation methanol synthesis device 4 and a synthesis gas methanol synthesis device 5.

The coal gasification device 1 has a coal inlet for coal, a steam inlet for steam, an oxygen inlet for oxygen, and a raw coal gas outlet 11. The coal is gasified in the coal gasification apparatus 1, and the generated raw coal gas is discharged from the raw coal gas outlet 11. In a specific implementation, the coal-to-methanol system may further include a coal pretreatment device 10, and before introducing the coal into the coal gasification device 1, the coal is pretreated by the coal pretreatment device 10 to obtain coal powder or blocks of a certain size. The coal can be lignite, bituminous coal, subbituminous coal, anthracite and the like, and can also comprise a certain amount of biomass, domestic garbage and the like. Wherein, the crude gas produced by coal gasification contains carbon dioxide.

The inlet of the raw gas purification and cooling device 2 is communicated with the raw gas outlet 11 of the coal gasification device 1, and the raw gas purification and cooling device 2 is used for cooling and purifying the raw gas. The acid gas separation device 3 is communicated with the outlet of the raw gas purification and cooling device 2. That is to say, the raw gas discharged from the raw gas outlet 11 enters the raw gas purifying and cooling device 2, the raw gas purifying and cooling device 2 may specifically include a gas-solid dust removal module and a multi-stage waste heat boiler waste heat recovery module, etc., the raw gas purifying and cooling device 2 cools and removes the temperature and the dust of the raw gas, and the raw gas after cooling and dust removal enters the acid gas separation device 3 from the outlet of the raw gas purifying and cooling device 2.

The acid gas separation device 3 is used for separating the crude gas after cooling and purifying treatment so as to separate carbon dioxide, synthesis gas and hydrogen sulfide. Wherein the syngas comprises carbon monoxide and hydrogen. The acid gas separation device 3 has a carbon dioxide outlet 31 for discharging carbon dioxide, a syngas outlet 32 for discharging syngas, and a hydrogen sulfide outlet 33 for discharging hydrogen sulfide.

The carbon dioxide-methanol hydrogenation apparatus 4 has a carbon dioxide inlet 411 communicating with the carbon dioxide outlet 31 and a hydrogen inlet 412 into which hydrogen can enter. Specifically, the carbon dioxide discharged from the carbon dioxide outlet 31 of the acid gas separation device 3 may be pressurized and then enter the carbon dioxide-methanol hydrogenation synthesis device 4 through the carbon dioxide inlet 411. The carbon dioxide hydrogenation methanol synthesis device 4 is used for carrying out synthesis treatment on carbon dioxide and hydrogen entering the device so as to obtain methanol. That is, the generated carbon dioxide is reused, and the emission reduction of the carbon dioxide is realized.

The synthesis gas methanol synthesis device 5 is communicated with the synthesis gas outlet 32, the synthesis gas containing carbon monoxide and hydrogen separated by the acid gas separation device 3 enters the synthesis gas methanol synthesis device 5, and the synthesis gas methanol synthesis device 5 is used for performing synthesis treatment on the synthesis gas to obtain methanol.

This coal system methanol system can also include sulphur recovery unit 30, and sulphur recovery unit 30 and hydrogen sulfide export 33 intercommunication are used for retrieving hydrogen sulfide to obtain sulphur product, for example sulphur etc..

In the zero-carbon-emission coal-to-methanol system provided by the embodiment, the raw gas generated by the coal gasification device 1 is cooled and purified by the raw gas purification and cooling device 2, and the raw gas treated by the cooling and purification device is cooled and purified by the acid gas separation device 3 to separate carbon dioxide, synthesis gas and hydrogen sulfide; the synthesis gas and the methanol synthesis device 5 are used for synthesizing the separated synthesis gas to obtain methanol, and the carbon dioxide hydrogenation methanol synthesis device 4 is used for synthesizing the separated carbon dioxide to obtain methanol, so that the carbon dioxide emission reduction is realized, the utilization efficiency of carbon in coal is improved, the consumption of coal is not increased, the methanol productivity is increased, and considerable economic benefit is brought.

With continued reference to fig. 1, the carbon dioxide-hydromethanol synthesis unit 4 may specifically include: a carbon dioxide hydrogenation methanol synthesis module 41 and a first temperature reduction separation module 42. The carbon dioxide-hydrogenated methanol synthesis module 41 has a carbon dioxide inlet 411 and a hydrogen inlet 412, and is used for performing synthesis treatment on carbon dioxide and hydrogen to obtain a first crude product containing methanol. The first cooling separation module 42 is used for cooling separation of the first crude product to obtain methanol.

That is, the carbon dioxide separated by the acid gas separation device 3 enters the carbon dioxide-methanol hydrogenation synthesis module 41 through the carbon dioxide inlet 411, the hydrogen enters the carbon dioxide-methanol hydrogenation synthesis module 41 through the hydrogen inlet 412, and the hydrogen and the carbon dioxide are synthesized in the carbon dioxide-methanol hydrogenation synthesis module 41 to generate a first crude product containing methanol, wherein the first crude product specifically may include methanol, a small amount of carbon monoxide, unconverted carbon dioxide and hydrogen. The first crude product enters the first cooling separation module 42, and the first cooling separation module 42 cools and separates the first crude product to obtain methanol. The first temperature-decreasing separation module 42 has a methanol outlet 421 for discharging methanol and a gas outlet for discharging other gases than methanol.

The carbon dioxide-hydrogenated methanol synthesis module 41 may specifically include a synthesis tower filled with a low-temperature high-activity carbon dioxide-hydrogenated methanol synthesis catalyst, such as a copper Cu-based catalyst and a molybdenum-based catalyst, i.e., a Cu-Zn-Al-Zr system catalyst or a molybdenum sulfide-based catalyst. The catalyst can be prepared by a coprecipitation method, a combustion synthesis method, a hydrothermal method, a polymer precursor method, a co-impregnation method and the like. Preferably coprecipitation method, combustion synthesis method and hydrothermal method. A plate heat exchanger or a tube heat exchanger is adopted in the catalyst bed layer for heat exchange, the temperature of the catalyst bed layer is controlled, and a certain amount of saturated steam is generated as a byproduct. Wherein, the pressure in the synthesis tower can be 2.5-5MPa, the temperature is 150-250 ℃, and the hydrogen-carbon ratio is 2.9-3.1. Keeping the space velocity at 3000-10000 ml/(g cat h), the conversion rate of carbon dioxide per pass is more than 20 percent, and the selectivity of methanol is more than 80 percent.

Referring to fig. 1, the carbon dioxide-hydrogenated methanol synthesis apparatus 4 further includes a first heat recovery module 43, and the first heat recovery module 43 is connected to the carbon dioxide-hydrogenated methanol synthesis module 41. Since the preparation of methanol by carbon dioxide hydrogenation is a strong exothermic reaction, the first heat recovery module 43 is arranged to recover the heat generated by the carbon dioxide hydrogenation methanol synthesis module 41 during the synthesis process. For example, the first heat recovery module 43 outputs steam by absorbing heat for use by other devices requiring steam.

With continued reference to fig. 1, the syngas methanol synthesis plant 5 may specifically include: a syngas methanol synthesis module 51 and a second reduced temperature separation module 52. The synthesis gas methanol synthesis module 51 is configured to perform synthesis processing on the synthesis gas to obtain a second crude product containing methanol. The second cooling separation module 52 is configured to cool and separate the second crude product to obtain methanol.

That is, the synthesis gas separated by the acid gas separation unit 3 enters the synthesis gas methanol synthesis module 51 to be subjected to synthesis treatment, and a second crude product is produced. The second crude product may comprise in particular methanol, unconverted carbon monoxide, hydrogen. Specifically, the synthesis gas methanol synthesis module 51 is provided with a synthesis gas methanol synthesis catalyst, such as Cu-Zn-Al, which performs a synthesis reaction at a set temperature and pressure to obtain the second crude product. Wherein, the pressure in the synthesis gas methanol synthesis module 51 can be 8-8.6 Mpa, and the temperature can be 230-280 ℃. The second crude product enters the second cooling separation module 52, and the second cooling separation module 52 cools and separates the first crude product to obtain methanol. The second temperature decreasing separation module 52 has a methanol outlet 521 for discharging methanol and a gas outlet for discharging other gases than methanol.

Referring to fig. 1, the synthesis gas methanol synthesis apparatus 5 further comprises a second heat recovery module 53, and the second heat recovery module 53 is connected to the synthesis gas methanol synthesis module 51. Since the carbon monoxide hydrogenation for preparing methanol is a strong exothermic reaction, the second heat recovery module 53 is arranged to recover the heat generated by the synthesis gas methanol synthesis module 51 in the synthesis process. For example, the second heat recovery module 53 absorbs heat to output steam for other devices requiring steam.

Further, the coal-to-methanol system further comprises a methanol purification device 6 and a methanol tank area 61. The methanol purification device 6 has a methanol inlet, and the methanol inlet is respectively communicated with the methanol outlet 421 of the carbon dioxide hydrogenation methanol synthesis device 4 and the methanol outlet 521 of the synthesis gas methanol synthesis device 5. The methanol purification device 6 is used for purifying the methanol to obtain refined alcohol, so that the purity of the methanol is improved. Specifically, methanol can be purified step by step through a multistage rectifying device to obtain refined alcohol, the refined alcohol is sent to a methanol tank area 61 to be stored, and a methanol product can be output by the methanol tank area 61.

In a specific implementation, the coal-to-methanol system may further include a methanol conversion and utilization device, and the methanol conversion and utilization device may be configured to convert and utilize the refined alcohol, for example, convert the refined alcohol in situ, and may specifically synthesize downstream products such as olefins and aromatics.

In addition, the refined alcohol can be transported to various places for use through a transportation device (such as a methanol tank car), such as a region or a link needing hydrogen. Specifically, methanol is reformed to obtain hydrogen for consumption and use as hydrogen energy. The methanol storage and transportation technology is mature, the cost is low, and the problems of difficult hydrogen storage and transportation and high cost in the hydrogen energy storage and transportation industry are further solved.

The coal-to-methanol system further comprises a mixed gas distribution supercharging device 7, and the mixed gas distribution supercharging device 7 is provided with a gas inlet and a circulating gas outlet. The carbon dioxide-hydrogenated methanol synthesis apparatus 4 has a first discharge port through which the unconverted raw gas can be discharged, and a recycle gas inlet 413. The first discharge port is specifically arranged on the first temperature-reducing separation module 42, and the recycle gas inlet 413 is specifically arranged on the carbon dioxide hydrogenation methanol synthesis module 41. The synthesis gas methanol synthesis unit 5 has a second discharge port from which unconverted feed gas can be discharged. The second discharge port is particularly disposed on the second desuperheating separation module 52. The first discharge port and the second discharge port are respectively communicated with a gas inlet of the mixing gas distribution supercharging device 7, and the circulating gas outlet is communicated with a circulating gas inlet 413. The mixed gas distribution supercharging device 7 is used for mixing and supercharging hydrogen and unconverted feed gas entering from the gas inlet to obtain circulating gas, and the circulating gas enters the carbon dioxide hydrogenation methanol synthesis device 4 through a circulating gas outlet and a circulating gas inlet 413 in sequence. In this embodiment, the gas inlet may specifically include a hydrogen inlet for hydrogen to enter the hybrid distribution and pressurization device 7 and a raw material gas inlet for unconverted raw material gas to enter the hybrid distribution and pressurization device 7.

That is to say, the methanol separated by the first cooling separation module 42 and the methanol separated by the second cooling separation module 52 enter the methanol purification device 6 through the methanol inlet, and the methanol purification device 6 purifies the methanol to obtain refined alcohol. The other gases (including carbon monoxide, carbon dioxide and hydrogen) except the methanol separated by the first temperature reduction separation module 42, the other gases (including carbon monoxide and hydrogen) except the methanol separated by the second temperature reduction separation module 52 and the hydrogen respectively enter the mixed gas distribution pressurizing device 7, and are sent to the carbon dioxide hydrogenation methanol synthesis module 41 to participate in the synthesis of the methanol again after being mixed and pressurized, so that the methanol conversion rate and the carbon dioxide emission reduction are further improved.

In some embodiments, the coal-to-methanol system further includes a water electrolysis hydrogen production unit 8. The hydrogen outlet 81 of the electrolyzed water hydrogen production device 8 is respectively communicated with the hydrogen inlet 412, the synthesis gas methanol synthesis device 5 and the gas inlet of the mixed gas distribution supercharging device 7, so as to provide hydrogen (i.e. green hydrogen) for the carbon dioxide hydrogenation methanol synthesis device 4, the synthesis gas methanol synthesis device 5 and the mixed gas distribution supercharging device 7, so as to adjust the hydrogen-carbon ratio in the carbon dioxide hydrogenation methanol synthesis device 4, the hydrogen-carbon ratio in the synthesis gas methanol synthesis device 5 and the hydrogen-carbon ratio in the mixed gas distribution supercharging device 7, thereby ensuring that the hydrogen-carbon ratio in each device is in a proper range, and further improving the productivity of methanol.

It is understood that the hydrogen source in the mixed gas distribution pressurization device 7 can be derived from the water electrolysis hydrogen production device 8, and other hydrogen supply sources do not need to be arranged for the mixed gas distribution pressurization device 7.

Wherein, the oxygen outlet 82 of the water electrolysis hydrogen production device 8 is communicated with the coal gasification device 1 to provide oxygen (i.e. green oxygen) for the coal gasification device 1.

In concrete implementation, the hydrogen discharged from the hydrogen outlet 81 of the water electrolysis hydrogen production device 8 can be distributed by the green hydrogen distribution device 80, so that a part of the hydrogen enters the carbon dioxide hydrogenation methanol synthesis device 4 from the hydrogen inlet 412 of the carbon dioxide hydrogenation methanol synthesis device 4, the hydrogen-carbon ratio in the carbon dioxide hydrogenation methanol synthesis device 4 is adjusted, and the methanol conversion rate is improved. And the other part of the hydrogen enters the synthesis gas methanol synthesis device 5 to adjust the hydrogen-carbon ratio in the synthesis gas methanol synthesis device 5, such as the hydrogen-carbon ratio is 1.95-2.3, so that the conversion rate of the methanol is improved. The green hydrogen distribution device 80 also distributes a part of hydrogen to the mixed gas distribution supercharging device 7 to mix with the unconverted raw material gas entering the mixed gas distribution supercharging device 7, adjusts the hydrogen-carbon ratio of the gas, and then enables the gas to enter the carbon dioxide hydrogenation methanol synthesis device 4 to participate in the synthesis treatment again. Other parts of the hydrogen gas are used as hydrogen energy sources to provide the hydrogen gas for other systems or equipment.

The coal-to-methanol system may also include a renewable energy power generation device 9 and an electric boiler device 90. The renewable energy power generation device 9 specifically includes a renewable energy power generation device that does not generate carbon emission, such as solar energy, hydraulic energy, wind energy, geothermal energy, tidal energy, and the like, and may be a single energy source or a combined form. The device does not produce carbon emission, and the green electricity of production includes direct current and alternating current, to the different demand condition of relevant system to direct current, alternating current, converts the utilization to it, supplies complete set system power demand.

Referring to fig. 1, the renewable energy power generation device 9 is used at least for supplying power to the electric boiler device 90 and the electrolytic water hydrogen production device 8. The water is catalyzed and electrolyzed by green electricity generated by a renewable energy power generation device 9, and the water is specifically divided into an alkaline water electrolysis system, a proton exchange membrane water electrolysis system and a high-temperature solid oxide water electrolysis system according to different electrolysis processes. And D, introducing direct current into the electrolytic water system, and enabling water molecules to generate electrochemical reaction on the electrodes to be decomposed into hydrogen and oxygen so as to obtain green hydrogen and green oxygen, so that the green hydrogen and the green oxygen are provided for the whole system.

Wherein, the steam outlet of the electric boiler device 90 is communicated with the coal gasification device 1 to provide steam (i.e. green steam) for the coal gasification device 1, so that the steam generated by the electric boiler device 90 can be effectively utilized, and the energy is saved. The electric boiler device 90 is also used for supplying green electricity to the coal gasification device 1.

By connecting the coal gasification device 1 with a matched public engineering system (such as a renewable energy power generation device 9, a water electrolysis hydrogen production device 8 and an electric boiler device 90), the whole public engineering system does not generate carbon emission, so that hydrogen and oxygen required by the whole system are green hydrogen and green oxygen, namely the green hydrogen and the green oxygen are from the green electricity water electrolysis hydrogen production device 8 (namely the water is subjected to catalytic electrolysis by adopting electric power generated by renewable energy), and the combination of renewable energy power generation, a water electrolysis hydrogen production technology and a coal methanol production technology is realized.

Taking a factory producing 60 ten thousand tons of methanol annually as an example, the existing coal-to-methanol process is compared with the zero-carbon-emission coal-to-methanol process provided by the embodiment, and the specific results are shown in table 1 below:

TABLE 1

In the embodiment, the methanol synthesis is carried out by taking carbon dioxide as a carbon resource according to the calculation of 90% of methanol selectivity and 95% of total CO2 conversion, and compared with the existing coal-based methanol preparation, the process route omits units such as gasification, transformation, purification and the like, and the water consumption is reduced by about 50%.

By using the zero-carbon-emission coal-to-methanol system provided by the embodiment on a methanol scale of 60 ten thousand tons/year, the scale of the existing coal-to-methanol system can be reduced to 17.65 ten thousand tons, CO2 discharged in the process is recycled for thermal catalytic conversion, the same methanol production scale can be realized, the coal can be reduced by 71 percent, the water can be saved by 35 percent, and the zero emission of carbon dioxide can be realized.

The coal-to-methanol system with zero carbon emission provided by the embodiment solves the problems of high carbon emission, high water consumption, large fluctuation of methanol price due to coal price, poor technical economy and the like existing in the existing coal-to-methanol process. By capturing carbon dioxide generated in the coal conversion and utilization process and carrying out chemical conversion, the carbon dioxide discharged in the coal use process is used as a carbon resource, so that the carbon dioxide emission reduction is realized, the consumption of fossil energy such as coal and the like is replaced, the energy safety is ensured, the consumption of water resources and pollution discharge are reduced, and considerable economic benefit can be created.

In addition, the zero-carbon-emission coal-to-methanol system provided by the embodiment converts light energy, heat energy, surplus electric energy and the like in a specific period of time through coupling complementation with novel renewable energy sources, provides green electricity, green hydrogen, green oxygen and the like required by the coal chemical industry, and realizes storage and transportation of the renewable energy sources. The methanol with a huge market application prospect is obtained while zero carbon emission is realized, the methanol can be used as a standard raw material in industries such as energy, fuel, chemical industry and the like, and can also be used as an energy storage medium, the methanol storage and transportation technology is mature, the cost is low, hydrogen obtained by electrolyzing water in areas rich in renewable energy can be stored in the energy storage medium and sent to a downstream production energy consumption area for conversion, acquisition and utilization, and the problems of difficult hydrogen storage and transportation and high cost in the hydrogen energy storage and transportation industry are solved.

The embodiment also provides a method for preparing methanol from coal, which can be performed by part or all of the coal-to-methanol system with zero carbon emission provided by the embodiment to achieve carbon dioxide emission reduction and efficient methanol preparation.

Referring to fig. 1 and 2, the method includes:

s101, feeding the coal material into a coal gasification device, and carrying out gasification reaction on the coal material in the coal gasification device to generate crude coal gas.

And S102, introducing the crude gas into a crude gas purification cooling device for cooling and purification treatment.

S103, introducing the cooled and purified crude gas into an acid gas separation device, so that the acid gas separation device separates the cooled and purified crude gas to separate out carbon dioxide, hydrogen sulfide and synthesis gas.

And S104, introducing the hydrogen and the separated carbon dioxide into a carbon dioxide hydrogenation methanol synthesis device so that the carbon dioxide hydrogenation methanol synthesis device performs synthesis treatment on the hydrogen and the carbon dioxide to obtain methanol.

In this step, the hydrogen and the separated carbon dioxide may be introduced into the carbon dioxide-hydrogenated methanol synthesis module, so that the carbon dioxide-hydrogenated methanol synthesis module performs a synthesis process on the hydrogen and the carbon dioxide to obtain a first crude product containing methanol. The carbon dioxide hydrogenation methanol synthesis module is provided with a catalyst, and the catalyst can specifically comprise at least one of a copper-based catalyst and a molybdenum-based catalyst. Then the first crude product is introduced into the first cooling separation module, so that the first cooling separation module cools and separates the first crude product to obtain the methanol.

Wherein, the synthesis reaction pressure of the carbon dioxide hydrogenation methanol synthesis device is controlled to be 2.5-5MPa, the temperature is 150-250 ℃, and the hydrogen-carbon ratio is 2.9-3.1. Keeping the space velocity at 3000-10000 ml/(g cat h), the conversion rate of carbon dioxide per pass is more than 20 percent, and the selectivity of methanol is more than 80 percent.

And S105, introducing the separated synthesis gas into a synthesis gas methanol synthesis device so that the synthesis gas methanol synthesis device performs synthesis treatment on the synthesis gas to obtain methanol.

In this step, the separated syngas may be introduced into the syngas methanol synthesis module, so that the syngas methanol synthesis module performs a synthesis process on the syngas to obtain a second crude product containing methanol. And then introducing the second crude product into a second cooling separation module so that the second cooling separation module cools and separates the second crude product to obtain the methanol.

It should be noted that step S104 and step S105 may be performed simultaneously or sequentially.

In the method for preparing methanol from coal, the raw gas generated by the coal gasification device is cooled and purified by the raw gas purification and cooling device, and the raw gas treated by the cooling and purification device is cooled and purified by the acid gas separation device to separate carbon dioxide, synthesis gas and hydrogen sulfide; the synthesis gas methanol synthesis device is used for synthesizing the separated synthesis gas to obtain methanol, and the carbon dioxide hydrogenation methanol synthesis device is used for synthesizing the separated carbon dioxide to obtain methanol, so that carbon dioxide generated in the process of preparing methanol from coal is used as a carbon resource to be further converted into methanol through synthesis while the methanol from coal is prepared, namely, the preparation amount of methanol is increased while the carbon dioxide is reduced in emission, and considerable economic benefit is brought.

Further, after the above step S104 and step S105, the method further includes:

and introducing the methanol into a methanol purification device so that the methanol purification device can purify the methanol to obtain refined alcohol. Specifically, the obtained refined alcohol can be converted and utilized to obtain a target product, and the target product can specifically comprise at least one of olefin, aromatic hydrocarbon or hydrogen.

In some embodiments, the method may further comprise:

and introducing the unconverted raw gas discharged by the carbon dioxide hydrogenation methanol synthesis device and the unconverted raw gas discharged by the synthesis gas methanol synthesis device into a mixed gas distribution pressurizing device, and introducing hydrogen into the mixed gas distribution pressurizing device, so that the mixed gas distribution pressurizing device performs mixed pressurization on the unconverted raw gas and the hydrogen to obtain the circulating gas. And then introducing the circulating gas into a carbon dioxide hydrogenation methanol synthesis device to further participate in synthesis, thereby further improving the emission reduction of carbon dioxide and the conversion rate of methanol.

In addition, the method further comprises:

and introducing at least part of hydrogen generated by the water electrolysis hydrogen production device into the carbon dioxide hydrogenation methanol synthesis device and the synthesis gas methanol synthesis device so as to provide hydrogen for the carbon dioxide hydrogenation methanol synthesis device and the synthesis gas methanol synthesis device. And introducing oxygen generated by the water electrolysis hydrogen production device into the coal gasification device so as to provide oxygen for the coal gasification device. And introducing steam generated by the electric boiler device into the coal gasification device so as to provide the steam for the coal gasification device.

Wherein, the power source of the water electrolysis hydrogen production device and the electric boiler device can be a renewable energy power generation device. Carbon dioxide greenhouse gas emission is not generated in the whole process, and green electricity is obtained and is used for power supply required by the whole system.

The specific implementation manner and the implementation principle of the method for preparing methanol from coal provided by this embodiment are the same as those of the above embodiments, and can bring about the same or similar technical effects, and are not described herein again one by one, and reference may be specifically made to the description of the embodiment of the coal-to-methanol system with zero carbon emission.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present disclosure, which enable those skilled in the art to understand or practice the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coal-to-methanol system with zero carbon emission is characterized by comprising a coal gasification device (1), a raw gas purification and cooling device (2), an acid gas separation device (3), a carbon dioxide hydrogenation methanol synthesis device (4) and a synthesis gas methanol synthesis device (5);

the coal gasification device (1) is used for carrying out gasification reaction on coal materials to generate crude coal gas; the raw gas purification and cooling device (2) is communicated with a raw gas outlet (11) of the coal gasification device (1) and is used for carrying out cooling and purification treatment on the raw gas;

the acid gas separation device (3) is communicated with the raw gas purification and cooling device (2) and is used for separating the raw gas subjected to cooling and purification treatment to separate carbon dioxide, synthesis gas and hydrogen sulfide; the acid gas separation unit (3) having a carbon dioxide outlet (31) for the discharge of carbon dioxide, a syngas outlet (32) for the discharge of syngas, and a hydrogen sulfide outlet (33) for the discharge of hydrogen sulfide;

the carbon dioxide hydrogenation methanol synthesis device (4) is provided with a carbon dioxide inlet (411) communicated with the carbon dioxide outlet (31) and a hydrogen inlet (412) for hydrogen to enter, and the carbon dioxide hydrogenation methanol synthesis device (4) is used for carrying out synthesis treatment on the carbon dioxide and the hydrogen to obtain methanol; the synthesis gas methanol synthesis device (5) is communicated with the synthesis gas outlet (32) and is used for carrying out synthesis treatment on the synthesis gas to obtain methanol.

2. The zero-carbon-emission coal-to-methanol system according to claim 1, wherein the carbon dioxide hydrogenation methanol synthesis device (4) comprises a carbon dioxide hydrogenation methanol synthesis module (41) and a first temperature reduction separation module (42);

the carbon dioxide hydromethanol synthesis module (41) has the carbon dioxide inlet (411) and the hydrogen inlet (412) for performing a synthesis process on the carbon dioxide and the hydrogen to obtain a first crude product comprising methanol; the first cooling separation module (42) is used for cooling separation of the first crude product to obtain the methanol.

3. The zero-carbon-emission coal-to-methanol system according to claim 1, wherein the syngas methanol synthesis plant (5) comprises a syngas methanol synthesis module (51) and a second desuperheating separation module (52);

the synthesis gas methanol synthesis module (51) is used for carrying out synthesis treatment on the synthesis gas to obtain a second crude product containing methanol; the second cooling separation module (52) is used for cooling separation of the second crude product to obtain the methanol.

4. The zero-carbon-emission coal-to-methanol system according to claim 1, further comprising a methanol purification device (6);

the methanol purification device (6) is provided with a methanol inlet which is respectively communicated with a methanol outlet (421) of the carbon dioxide hydrogenation methanol synthesis device (4) and a methanol outlet (521) of the synthesis gas methanol synthesis device (5); the methanol purification device (6) is used for purifying the methanol to obtain refined alcohol.

5. The zero carbon emission coal-to-methanol system of claim 1, further comprising a sulfur recovery device (30);

the sulfur recovery device (30) is communicated with the hydrogen sulfide outlet (33) and is used for recovering the hydrogen sulfide to obtain a sulfur product.

6. The zero-carbon-emission coal-to-methanol system according to claim 1, further comprising a mixed gas distribution supercharging device (7);

the carbon dioxide hydrogenation methanol synthesis device (4) is provided with a first discharge port for discharging unconverted raw gas and a circulating gas inlet (413), the synthesis gas methanol synthesis device (5) is provided with a second discharge port for discharging unconverted raw gas, and the first discharge port and the second discharge port are respectively communicated with the gas inlet of the mixing gas distribution pressurizing device (7);

the mixed gas distribution supercharging device (7) is used for mixing and supercharging the hydrogen and the unconverted feed gas entering from the gas inlet to obtain a recycle gas, and the recycle gas enters the carbon dioxide hydrogenation methanol synthesis device (4) from the recycle gas inlet (413).

7. The zero-carbon-emission coal-to-methanol system according to any one of claims 1 to 6, further comprising a water electrolysis hydrogen production device (8);

a hydrogen outlet (81) of the water electrolysis hydrogen production device (8) is at least communicated with the hydrogen inlet (412) and the synthesis gas methanol synthesis device (5) so as to provide hydrogen to at least the carbon dioxide hydrogenation methanol synthesis device (4) and the synthesis gas methanol synthesis device (5);

an oxygen outlet (82) of the water electrolysis hydrogen production device (8) is communicated with the coal gasification device (1) so as to provide oxygen for the coal gasification device (1).

8. The zero-carbon-emission coal-to-methanol system according to claim 7, further comprising a renewable energy power generation device (9) and an electric boiler device (90);

the renewable energy power generation device (9) is at least used for supplying power to the electric boiler device (90) and the water electrolysis hydrogen production device (8);

the steam outlet of the electric boiler device (90) is communicated with the coal gasification device (1) to provide steam for the coal gasification device (1).

9. A method for coal-to-methanol using the zero-carbon-emission coal-to-methanol system of any one of claims 1 to 8, the method comprising:

introducing the cooled and purified crude gas into an acid gas separation device so that the acid gas separation device separates the cooled and purified crude gas to separate out carbon dioxide, hydrogen sulfide and synthesis gas;

introducing hydrogen and the separated carbon dioxide into a carbon dioxide hydrogenation methanol synthesis device so that the carbon dioxide hydrogenation methanol synthesis device carries out synthesis treatment on the hydrogen and the carbon dioxide to obtain methanol;

10. The coal-to-methanol method according to claim 9, wherein the synthesis reaction pressure in the carbon dioxide-to-methanol hydrogenation apparatus is 2.5-5MPa, the reaction temperature is 150-250 ℃, the hydrogen-to-carbon ratio is 2.9-3.1, the space velocity is kept at 3000-10000 ml/(g cat h), the single-pass conversion rate of carbon dioxide is more than 20%, and the methanol selectivity is more than 80%.

11. The method for preparing methanol from coal according to claim 9, wherein the step of introducing the hydrogen and the separated carbon dioxide into a carbon dioxide-hydrogenated methanol synthesis unit so that the carbon dioxide-hydrogenated methanol synthesis unit performs a synthesis process on the hydrogen and the carbon dioxide to obtain methanol comprises:

12. The coal-to-methanol method according to claim 9, wherein the step of passing the separated synthesis gas to a synthesis gas methanol synthesis unit so that the synthesis gas methanol synthesis unit performs a synthesis treatment on the synthesis gas to obtain methanol comprises:

13. The coal-to-methanol method of claim 9, further comprising:

converting and utilizing the refined alcohol to obtain a target product; wherein the target product comprises at least one of an olefin, an aromatic hydrocarbon, or hydrogen.

14. The coal-to-methanol method of claim 9, further comprising:

introducing the unconverted raw gas discharged by the carbon dioxide hydrogenation methanol synthesis device and the unconverted raw gas discharged by the synthesis gas methanol synthesis device into a mixed gas distribution pressurizing device, and introducing hydrogen into the mixed gas distribution pressurizing device, so that the mixed gas distribution pressurizing device performs mixed pressurization on the unconverted raw gas and the hydrogen to obtain a circulating gas;

15. The coal-to-methanol method according to any one of claims 9 to 14, further comprising:

introducing at least part of hydrogen generated by a water electrolysis hydrogen production device into the carbon dioxide hydrogenation methanol synthesis device and the synthesis gas methanol synthesis device so as to provide hydrogen for the carbon dioxide hydrogenation methanol synthesis device and the synthesis gas methanol synthesis device;

introducing steam generated by an electric boiler device into the coal gasification device so as to provide the steam for the coal gasification device; wherein power is supplied to the electrolyzed water hydrogen production device and the electric boiler device through a renewable energy power generation device.