KR101557442B1

KR101557442B1 - Gasifier For Synthesis Of Methane Without Catalyst, And Synthesizing Method Of Methan Without Catalyst

Info

Publication number: KR101557442B1
Application number: KR1020140164342A
Authority: KR
Inventors: 유정석; 이영훈; 김봉근
Original assignee: 두산중공업 주식회사
Priority date: 2014-11-24
Filing date: 2014-11-24
Publication date: 2015-10-19

Abstract

The present invention relates to a non-catalytic gasifier and a non-catalytic methane synthesis method for methane synthesis, and more particularly, to a process for producing a methane- And more particularly, to a non-catalytic gasifier and a non-catalytic synthesis method capable of producing methane with high efficiency with a single gasifier without using a catalyst.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for synthesizing methane,

In recent years, interest in coal gasification technology for producing clean fuel from cheap coal has been increasing, as the price of natural gas has risen due to the recent rise in oil prices. As coal gasification technology is developed, synthesis gas The production of synthetic natural gas (SNG) has been attracting attention as an economical utilization method for coal gasification. Production of synthetic natural gas by coal gasification has been actively commercialized recently in the United States, China, and the like.

However, as shown in FIGS. 1 and 2, the synthetic gas production process through the conventional coal gasification is a process in which the synthesis gas produced in the gasifier is subjected to the first water gas shift process and the second methanolization process Methanation) process. However, the process is complicated and requires a lot of space, resulting in poor economical efficiency.

Particularly, existing synthetic natural gas production processes are essentially processes in which a catalyst is to be used, and the recycling rate and productivity of the catalyst are remarkably low, and it is difficult to increase the capacity.

On the other hand, the main reaction and the heat of reaction, which make synthetic natural gas mainly composed of methane using the synthesis gas as a reaction gas, are as follows.

CO + 3H2 -> CH4 + H2O (reaction heat: 206 kJ / mol)

CO2 + 4H2 - > CH4 + 2H2O (reaction heat: 165 kJ / mol)

As the reaction temperature increases thermodynamically, the yield of methane is lowered. In the natural gas synthesis reaction, the reaction itself is accompanied by strong heat generation, and the methane yield may decrease with time. Therefore, it is very important in the synthesis process design to effectively control the reaction heat in the natural gas synthesis process accompanied by strong heat generation.

In addition, in the natural gas synthesis process, a Ni-based catalyst is generally used. In general, when the Ni-based catalyst is exposed to 700 ° C or more, the life of the catalyst is remarkably reduced by sintering. Therefore, the use of the catalyst in the natural gas synthesis process accompanied by the strong heat generation as described above has become a factor to lower the overall synthesis efficiency.

In addition, conventional processes for synthesizing natural gas, particularly water gas shift process, use a large amount of water. In addition, not only a separate cost is required to process the large amount of water, There was a problem that it could be a cause.

Korean Laid-Open Publication No. 2014-0084486 (Publication date: 2014.07.07) Korean Laid-Open Publication No. 2013-0067012 (Published on 2013.06.21)

DISCLOSURE Technical Problem In order to solve the above problems, it is an object of the present invention to provide a gasifier and a synthesis method using a single reactor, which are simple in process and small in space consumption, do.

It is another object of the present invention to provide a gasifier and a synthesis method that can increase operational reliability without using a catalyst, and can downsize and mass-scale production as well as minimize steam consumption.

In order to accomplish the above object, the present invention provides a combustion apparatus comprising: a combustion section (10) for burning fuel and oxygen to produce carbon dioxide and steam; A gasification unit 20 for generating carbon monoxide and hydrogen by reacting carbon dioxide and steam introduced from the combustion unit 10 with fuel introduced from the outside; And a methanation unit 30 for generating methane by reacting carbon monoxide and hydrogen introduced from the gasification unit 20 with steam introduced from the outside, and a methanation unit 30 for methane synthesis.

The burner 10 may include one or more burners for supplying fuel and oxygen into the combustion unit 10. The fuel and oxygen supplied from the burner may be supplied to the combustion unit 10 in a predetermined direction So that swirling swells can be formed. In addition, it is preferable that the nonflammable component contained in the fuel is melted and discharged to the lower portion of the combustion unit 10.

The gasification unit 20 is installed to communicate with the upper portion of the combustion unit 10 so that the carbon dioxide and steam generated in the combustion unit 10 rise and flow into the gasification unit 20.

The gasification unit 20 may include one or more fuel supply nozzles for supplying fuel into the gasification unit 20 and the fuel supplied from the fuel supply nozzle 210 may be uniformly distributed along the inner wall of the gasification unit 20 It is possible to form a rising swirl. At this time, it is preferable that the direction of rotation of the swirl formed in the gasification unit 20 is opposite to the direction of rotation of the swirl formed in the combustion unit 10.

The methanation unit 30 is installed to communicate with the upper side of the gasification unit 20 so that the carbon monoxide and hydrogen generated by the gasification unit 20 rise and flow into the methanation unit 30.

The methanation unit 30 may include at least one steam supply nozzle for supplying steam into the methanation unit 30. The steam supplied from the steam supply nozzle is circulated in a predetermined direction along the inner wall of the methanation unit 30, So that a swirl can be formed. At this time, it is preferable that the direction of rotation of the swirl formed in the methanation part (30) is opposite to the direction of rotation of the swirl formed in the gasification part (20).

In order to control the temperature inside the gasifier, a water tube is formed along the wall surface of at least one of the combustion unit 10, the gasification unit 20, or the methanation unit 30, So that water or water vapor flows upward.

The water supplied to the water tube is heated while flowing along at least one of wall surfaces of the combustion unit 10, the gasification unit 20 or the methanation unit 30 and then discharged to the outside. In one embodiment, The internal temperature of the methanation unit can be maintained at 750 to 900 DEG C which is suitable for the synthesis reaction, as the water supplied to the methanation unit 30 flows along the wall surface of the methanation unit 30. [

At this time, the gasifier may further include a water drum 40 that receives heated water or steam from the water tube and supplies the cooled water back to the water tube.

In the meantime, the present invention provides a combustion method comprising: a combustion step of completely burning fuel and oxygen to generate carbon dioxide and steam; A gasification step of reacting carbon dioxide and steam generated in the combustion step with fuel to produce carbon monoxide and hydrogen; And a methanation step of reacting carbon monoxide and hydrogen produced in the gasification step with steam to produce methane.

Preferably, the combustion, gasification, and methanation steps are continuous in a continuous multistage reactor, wherein the neighboring stages of the reaction gases form opposite swirls.

In addition, the reaction of the gasification step and the methanation step may be performed using heat energy generated in the combustion step, and the steam supply from the outside is preferably performed only in the methanation step.

It is preferable that the cooling water flows through the wall surface of the reactor so that the cooling water regulates the temperature inside the reactor to a temperature range suitable for the gasification reaction or the methanation reaction.

The methane gasifier and the methane synthesis method of the present invention can continuously perform a series of combustion reaction, gasification reaction and methanation reaction in a continuous multi-stage reactor, thereby simplifying the process and minimizing the space consumption. In addition, since the catalyst is not used, the reliability of the operation can be enhanced, mass production can be facilitated, steam consumption can be minimized, and the reaction heat can be effectively controlled through the water tube installed on the wall.

1 and 2 - Process chart showing a conventional synthetic natural gas synthesis process
Fig. 3 is a cross-sectional view of a gasifier comprising a combustion section, a gasification section, and a methanation section of the present invention
Fig. 4 is a conceptual view showing the operation principle of the water tube installed on the wall surface of the gasifier of the present invention.

Hereinafter, the technical features of the present invention will be described in detail with reference to embodiments and drawings. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. shall.

Throughout this specification, when an element is referred to as "including" an element, it is understood that it may include other elements as well, without departing from the other elements unless specifically stated otherwise.

As shown in FIGS. 1 and 2, the conventional synthesis of methane is a synthesis of methane gas through a separate gas-gas conversion process and a methane synthesis process, .

Unlike conventional processes, the present invention is characterized in that a series of reactions for methane synthesis are carried out continuously in one reactor.

Specifically, the non-catalytic gasifier of the present invention includes a combustion section 10 for burning fuel and oxygen to produce carbon dioxide and steam as shown in FIG. 3; A gasification unit 20 for generating carbon monoxide and hydrogen by reacting carbon dioxide and steam introduced from the combustion unit 10 with fuel introduced from the outside; And a methanation unit 30 for generating methane by reacting carbon monoxide and hydrogen introduced from the gasification unit 20 with steam introduced from the outside. Hereinafter, the configuration of the gasifier will be described in detail.

The combustion unit 10 is a zone where fuel and oxygen, which are carbon-containing substances such as coal, are supplied and combusted to generate combustion gas of carbon dioxide and steam. The combustion unit 10 is preferably heated to a temperature at which incombustible components such as ash can be melted, and may be heated to 1500 ° C or higher in one embodiment. Therefore, in this temperature range, the complete combustion of the fuel is carried out to generate combustion gas mainly containing carbon dioxide and water vapor, and the temperature of the combustion gas has a temperature sufficient to melt non-combustible components such as ash.

The burner 10 is provided with at least one burner for supplying fuel and oxygen into the reactor, and the burner completely burns the fuel to generate combustion gas. The configuration of the burner is not particularly limited as long as the fuel and the oxygen are supplied and the combustion is performed to generate the combustion gas.

At this time, in order to increase the residence time of the materials supplied from the burner in the combustion section, it is preferable that the combustion gases form a swirl which swirls in a constant direction along the inner wall of the combustion section 10. The burning direction of the burner is preferably a tangential direction of the inner end face of the combustion section 10 or a tangential direction of the swirl rather than the inner center of the combustion section 10 so that the combustion gases can form swirling along the inner wall Do.

In addition, a central portion of the combustion unit 10 is emptied by the upward movement of the combustion unit 10 along the inner wall of the combustion unit 10. At this time, a downward flow may be generated at the center of the combustion unit 10.

At this time, the incombustible components such as the ash melted by the combustion gas are collected and can be discharged to the lower part along with the downflow. The discharge portion may be configured to have a smaller cross sectional area as it goes down. The molten incombustible materials may be lowered while being rotated along the inner wall, and then solidified to form slag.

Meanwhile, the gasification unit 20 generates carbon monoxide and hydrogen by incomplete combustion reaction of carbon dioxide and steam introduced from the combustion unit 10 and fuel separately introduced into the gasification unit 20.

The gasification unit 20 is installed so as to communicate with the upper side of the combustion unit 10 so that the carbon dioxide and steam generated in the combustion unit 10 rise and flow into the gasification unit 20.

The gasification unit 20 is provided with one or more fuel supply nozzles for supplying fuel to the gasification unit 20. The fuel supplied from the nozzles undergoes an incomplete combustion reaction by the heat of the combustion gas and the carbon dioxide and steam contained in the combustion gas, And a synthesis gas containing hydrogen as a main component.

In this case, the main gasification reaction formula is as follows.

C + H2O ↔ CO + H2 + 131 MJ / kmol

C + CO2 ↔ 2CO + 172 MJ / kmol

CO + H2O ↔ CO2 + H2 - 41 MJ / kmol

It is not necessary to increase the temperature inside the gasification unit 20 to 1500 占 폚 to 1600 占 폚 or higher which is a temperature at which the incombustible components can be melted because the gasification unit 20 does not need melting of incombustible components such as ash. That is, since the gasification reaction is performed at a temperature of 1100 ° C to 1200 ° C, the gasification reaction of the combustion gas can be sufficiently performed only by the temperature of the combustion gas without a separate burner.

In order to increase the residence time in the reactor, the fuel supplied from the fuel supply nozzle preferably forms a swirl which swirls in a constant direction along the inner wall of the gasification unit 20, like the combustion unit 10.

At this time, it is preferable that the direction of rotation of the swirl formed in the gasification unit 20 is opposite to the direction of rotation of the swirl formed in the combustion unit 10. By forming the rotation directions of the neighboring reactors to be opposite to each other in this manner, the residence time of the reaction gases in the reactor can be further increased to improve the productivity and downsizing of the gasifier becomes possible.

Therefore, the spray direction of the fuel supply nozzle is preferably opposite to that of the burner of the combustion unit 10, so that the reaction gases can swirl along the inner wall in a direction opposite to the swirl of the combustion unit 10 Do.

The methanation unit 30 is a section for synthesizing methane by reacting carbon monoxide and hydrogen introduced from the gasification unit 20 with steam introduced from the outside.

The methanation unit 30 is installed to communicate with the upper side of the gasification unit 20 so that the carbon monoxide and hydrogen generated by the gasification unit 20 rise and flow into the methanation unit 30. [

The methanation unit 30 may include one or more steam supply nozzles for supplying steam to the inside of the methanation unit 30. The steam introduced from the nozzles reacts with carbon monoxide and hydrogen introduced from the gasification unit 20 to generate methane .

The methane synthesis reaction thermodynamically decreases the yield of methane as the reaction temperature rises. It is important to control the reaction temperature so as to maintain the temperature of 750-900 ° C. without increasing the reaction temperature too high. Therefore, the methanation reaction can be sufficiently performed only by the temperature of the synthesis gas generated in the gasification unit 20 without a separate burner, and a heat exchanger for cooling can be used if necessary.

In addition, since steam is introduced into only the methane synthesis step of the methanation unit 30, the consumption of steam can be reduced by 50% or more as compared with the conventional methane synthesis process using a large amount of water.

In order to increase the residence time in the reactor, the steam supplied from the steam supply nozzle preferably forms a swirl that swirls in a constant direction along the inner wall of the methanation unit 30. At this time, it is preferable that the direction of rotation of the swirl formed in the methanation part (30) is opposite to the direction of rotation of the swirl formed in the gasification part (20). By forming the rotation directions of the neighboring reactors to be opposite to each other in this manner, the residence time of the reaction gases in the reactor can be further increased to improve the productivity and downsizing of the gasifier becomes possible.

Therefore, the spraying direction of the steam supply nozzle is opposite to the spray direction of the nozzle of the gasification unit 20 so that the reaction gases can swirl along the inner wall in a direction opposite to the swirl of the methanation unit 30 .

4, in order to maintain the internal temperature of the reactor at the most suitable temperature range for each reaction, the gasifier 10, the gasification unit 20, or the methanation unit 30, as shown in FIG. 4, A water tube may be formed on at least one of the wall surfaces of the water tube so that water or water vapor flows upward along the water tube.

As described above, it is preferable that the internal temperature of the gasification unit 20 is maintained at a temperature suitable for the gasification reaction, that is, 1100 to 1200 ° C, and the internal temperature of the methanation unit 30 is 750 to 900 ° C .

Thus, the temperature of the gasification unit 20 and the methanation unit 30 can be controlled by gradually cooling the reaction gases as they rise along the inner wall. That is, the reaction gases rising along the inner wall heat-exchange with the water flowing in the water tube and gradually cool down. In the heat exchange process, the heated water is discharged to the outside and the cooled water is supplied into the water tube again.

At this time, the gasifier may further include a water drum 40 that receives heated water or steam from a water tube, stores the water, and supplies the cooled water back to the water tube.

The water tube may be formed on the wall surface of the gasifier in various manners. However, as shown in FIG. 4, the cooled water may flow into the lower end of the combustion unit 10, And the temperature of the gasification section 20 are controlled so as not to become higher than necessary, and the heated water is discharged again to the outside.

Thereafter, the cooled water flows into the upper end of the gasification unit 20 and is raised so as to control the temperature of the methanation unit 30 to be higher than necessary, and the heated water may be discharged to the outside have.

At this time, the heated water discharged from the gasification unit 20 and the water tube of the methanation unit 30 flows into the water drum 40 and is cooled, then flows into the combustion unit 10 or the gasification unit 20 .

The non-catalytic methane synthesis process using the gasifier of the present invention will be described in detail as follows.

The non-catalytic methane synthesis method of the present invention is characterized in that it is continuously carried out in a multi-stage reactor in which a combustion step, a gasification step and a methanation step are communicated.

First, the fuel and oxygen are injected at the lower end of the reactor and completely burned to generate carbon dioxide and steam. The carbon dioxide and steam generated in the first stage flow into the second stage in a rising air flow, and incomplete combustion reaction with the additional fuel introduced in the second stage produces carbon monoxide and hydrogen.

The carbon monoxide and hydrogen generated in the second stage are flowed into the third stage in an ascending current flow and react with the steam supplied in the third stage to finally produce methane. At this time, since the steam supply from the outside is performed only in the methanation step, the steam consumption amount can be reduced by 50% or more as compared with the conventional process.

In the first, second, and third stages, the reaction gases form swirls that swirl along the inner wall of the gasifier. In order to maximize the residence time and reaction efficiency of the reaction gases, It is desirable to form a swirl. At this time, the swirl direction can be controlled by adjusting the direction of the injection nozzle.

The gasification step and the methanation step in the second stage and the third stage are carried out by using the thermal energy generated in the combustion step without additional energy input. If necessary, the internal temperature of the second or third stage is subjected to gasification reaction Or to adjust the temperature range suitable for the methanation reaction, the cooling water flowing in the upward direction may flow through the reactor wall surface.

The methane gasifier and the methane synthesis method of the present invention can continuously perform combustion, gasification, and methanation reactions in a continuous multi-stage reactor, which has been conventionally performed by separate processes, thereby simplifying the process and minimizing the space consumption can do.

In addition, by allowing the reaction gases to form swirls in mutually opposite directions in each reaction step, the residence time of the reaction gases can be increased to increase the reaction efficiency and downsize the gasifier.

In addition, the steam consumption can be reduced by 50% or more by injecting steam only in the methanation step, and the reaction heat can be effectively controlled through the water tube installed on the wall, thereby improving the productivity without using the catalyst.

Accordingly, the non-catalytic gasifier and the synthesis method of the present invention have high operation reliability and are easy to mass-scale production, and can significantly reduce CAPEX / OPEX compared to existing methane production plants.

The present invention is not limited to the above-described specific embodiment and description, and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention as claimed in the claims. And such modifications are within the scope of protection of the present invention.

10: burner 20: gasifier
30: methanizing part 40: water drum

Claims

A combustion section (10) for burning fuel and oxygen to generate carbon dioxide and steam;
A gasification unit 20 for generating carbon monoxide and hydrogen by reacting carbon dioxide and steam introduced from the combustion unit 10 with fuel introduced from the outside; And
A methanation unit 30 for generating methane by reacting carbon monoxide and hydrogen introduced from the gasification unit 20 with steam introduced from outside;
Wherein the gas mixture is a mixture of methane and water.

The method according to claim 1,
Characterized in that the combustion section (10) comprises one or more burners for supplying fuel and oxygen into the combustion section (10).

3. The method of claim 2,
Wherein the fuel and oxygen supplied from the burner form a swirl that swirls in a constant direction along the inner wall of the combustion section (10).

The method according to claim 1,
Wherein the incombustible component contained in the fuel is melted and discharged to the lower portion of the combustion unit (10).

The method according to claim 1,
The gasification unit 20 communicates with the upper side of the combustion unit 10,
And the carbon dioxide and steam generated in the combustion unit (10) rise and flow into the gasification unit (20).

The method according to claim 1,
Characterized in that the gasification part (20) comprises at least one fuel supply nozzle for supplying fuel into the gasification part (20).

The method according to claim 6,
Wherein the fuel supplied from the fuel supply nozzle forms a swirl that swirls in a constant direction along the inner wall of the gasification unit (20).

8. The method of claim 7,
Wherein the rotating direction of the swirl formed in the gasification unit (20) is opposite to the rotating direction of the swirl formed in the combustion unit (10).

The method according to claim 1,
The methanation unit 30 communicates with the upper side of the gasification unit 20,
Wherein the carbon monoxide and hydrogen generated by the gasification unit (20) rise and flow into the methanation unit (30).

The method according to claim 1,
Wherein the methanation unit (30) comprises at least one steam supply nozzle for supplying steam into the methanation unit (30).

11. The method of claim 10,
Wherein the steam supplied from the steam supply nozzle forms a swirl which swirls in a constant direction along the inner wall of the methanation portion (30).

12. The method of claim 11,
Wherein the rotating direction of the swirl formed in the methanation unit (30) is opposite to the rotating direction of the swirl formed in the gasification unit (20).

The method according to claim 1,
A water tube is formed along the wall surface of at least one of the combustion unit 10, the gasification unit 20, or the methanation unit 30,
Wherein water or water vapor flows upward along the water tube. &Lt; RTI ID = 0.0 > 8. < / RTI >

14. The method of claim 13,
Characterized in that water supplied to the water tube is heated while flowing along at least one of wall surfaces of the combustion section (10), the gasification section (20), or the methanation section (30) Catalytic gasifier.

14. The method of claim 13,
Wherein the water supplied to the water tube flows along the wall surface of the methanation unit to cool the temperature of the methanation unit to 750 to 900 占 폚.

14. The method of claim 13,
Further comprising a water drum (40) for receiving the heated water or steam from the water tube and supplying the cooled water back to the water tube.

A combustion step of completely burning fuel and oxygen to produce carbon dioxide and steam;
A gasification step of reacting carbon dioxide and steam generated in the combustion step with fuel to produce carbon monoxide and hydrogen;
A methanation step of reacting carbon monoxide and hydrogen produced in the gasification step with steam to produce methane;
&Lt; / RTI >

18. The method of claim 17,
Wherein the combustion step, the gasification step, and the methanation step are continuously conducted in a continuous multi-stage reactor.

19. The method of claim 18,
Wherein the reaction gases in the neighboring stages form swirls in opposite directions to each other.

19. The method of claim 18,
Wherein the gasification step and the methanation step are carried out using thermal energy generated in the combustion step.

19. The method of claim 18,
Wherein the steam supply from the outside is performed only in the methanation step.

19. The method of claim 18,
Cooling water flows along the wall surface of the reactor,
Wherein the cooling water regulates a temperature inside the reactor to a temperature range of a gasification reaction or a methanation reaction.