WO2020067747A1

WO2020067747A1 - Internally recirculating pressurized oxy-fuel combustor

Info

Publication number: WO2020067747A1
Application number: PCT/KR2019/012556
Authority: WO
Inventors: 이영재; 김동희; 안형준; 이은도; 양원
Original assignee: 한국생산기술연구원
Priority date: 2018-09-28
Filing date: 2019-09-27
Publication date: 2020-04-02
Also published as: KR102077710B1

Abstract

The present invention relates to an internally recirculating pressurized oxy-fuel combustor, comprising: an outer wall; an inner wall which is provided inside the outer wall and defines an inner space; a burner which is provided at the lower part of the outer wall and positioned at the inner center of the inner wall and burns fuel and an oxidant; exhaust units which are provided at the lower part of the outer wall and positioned inside the inner wall and in the vicinity of the burner and discharge exhaust gas to the outside; heat transfer media which are solid spherical substances located between the outer wall and the inner wall and store the heat energy of exhaust gas and use same for heat exchange; and pipes which are provided between the outer wall and the inner wall and produce steam by means of heat exchange, wherein the inner wall has an open top and a through-hole, which is at the bottom thereof and via which gases can pass through, so that the exhaust gas generated by the combustion of the burner moves upwards inside the inner wall, then moves down along the space between the outer wall and the inner wall, and then moves to the inside of the inner wall, some of the exhaust gas that has moved to the inside of the inner wall is discharged via the exhaust units, the remainder of same recirculates the inside, and the fuel and oxidant injected into the burner are preheated by means of the recirculating exhaust gas.

Description

Internal recirculating pressurized oxygen generator

The present invention relates to a pressurized pure oxygen combustor, and more particularly, to a pressurized pure oxygen combustor with improved efficiency.

In general, combustion flue gas from a thermal power plant or a thermal power plant that uses heat for fuel combustion contains about 12 to 17% carbon dioxide, 76 to 78% nitrogen, 4 to 5% oxygen, and other trace amounts of moisture. SO _x and NO _x compounds. Among them, carbon dioxide is a major cause of global warming, so reducing its emissions has become an international concern.

The pure oxygen combustor has an advantage of reducing energy by using oxygen instead of air as an oxidizing agent, while reducing SO _x and NO _x compounds and generating high concentrations of CO ₂ , thereby reducing CO ₂ recovery costs.

As a method to increase efficiency in the process of using a pure oxygen combustor, a method of recovering waste heat of exhaust gas and performing preheating has been applied. Circulating the exhaust gas from outside to perform preheating and using a separate burner for preheating The disadvantage is that the equipment is complicated and the production cost is high. (Republic of Korea Patent Registration 10-1360515)

In addition, ceramic balls (or beads) are often used as a heat storage medium to improve performance in the heat exchange process, but when the size of the combustion flame is small, there is a problem that relatively excessive ceramic balls degrade efficiency. To this end, a technique has been developed to control the range of use of a pipe that performs heat exchange according to the difference in the amount of combustion, but it does not solve the problem of heat loss due to excessive ceramic balls. (Republic of Korea Patent Registration 10-0650602)

The present invention has been made to solve the problems of the prior art described above and has an object to provide an internal recirculating pressurized oxygen generator.

The internal recirculating pressurized oxygen generator according to the present invention for achieving the above object, the outer wall; An inner wall installed inside the outer wall to divide the inner space; A burner installed at a lower portion of the outer wall and located at an inner center of the inner wall to burn fuel and oxidant; An exhaust unit installed at a lower portion of the outer wall, located inside the inner wall, and disposed at the periphery of the burner to discharge exhaust gas to the outside; A heat-transferring medium used as a solid heat-spherical material located between the outer wall and the inner wall to accumulate heat energy of exhaust gas for heat exchange; And a pipe installed between the outer wall and the inner wall to produce steam through heat exchange, wherein the inner wall is open at the top and a through hole through which gas can pass is formed at the bottom, and exhaust generated by combustion of the burner Gas moves upward from the inside of the inner wall, descends along the space between the outer wall and the inner wall, then moves to the inside of the inner wall, and some of the exhaust gas moved to the inside of the inner wall is discharged through the exhaust portion and the rest is recirculated inside And, it is characterized by preheating the fuel and oxidant injected into the burner by the recirculated exhaust gas.

The pressure (P1) at the top of the inner space of the inner wall, the pressure (P2) at the top of the inner space of the outer wall, the pressure (P3) at the bottom of the inner space of the outer wall, and the pressure (P4) at the bottom of the inner space of the inner wall It is preferred that) is a relationship of P1> P2> P3> P4.

It is preferable to form a bottleneck structure in which the space through which the exhaust gas passes is narrowed on the upper portion of the inner wall.

It is preferable that the inner wall is a material for high temperature of 1300 ° C or higher.

It is preferable that the heat transfer medium is a ceramic ball, and further includes an adjustment means capable of adjusting the amount of the ceramic ball located between the outer wall and the inner wall.

Adjustment means is connected to the lower side of the outer wall to adjust the amount of the ceramic ball stored in the control space by moving the ceramic ball while moving up and down inside the control space and the control space for storing the ceramic ball It is good to include a regulator.

At this time, it is preferable that the height adjuster can move up and down inside the adjustment space through a threaded structure.

It may further include a device for applying vibration or shock from the outside to facilitate the movement of the ceramic ball.

It is preferable that a packing for maintaining pressure is installed at the bottom of the adjustment space.

It is preferable that the piping is arranged such that the heat exchange medium therein repeatedly rotates and descends while rotating the inside, so that the piping in the vertical direction is long, so as not to interfere with the movement of the ceramic balls.

The present invention configured as described above, by performing preheating in a manner that a portion of the exhaust gas is recirculated inside without using a separate external circulation device or an additional burner, can greatly increase the efficiency of the combustor with a relatively simple configuration. It has an effect.

In addition, by using a heat transfer medium positioned between the inner wall and the outer wall installed for internal circulation, there is an excellent effect that the heat exchange efficiency is greatly improved.

Furthermore, by providing a means for adjusting the amount of heat transfer medium located between the inner and outer walls, the amount of heat transfer medium is excessively large, thereby preventing the problem of inhibiting heat exchange efficiency.

Finally, since the temperature gradient inside the combustor is minimized, the heat transfer efficiency is increased, and the ratio of easily treatable components to the flue gas is increased, so there is an excellent effect of minimizing expensive materials and auxiliary equipment.

1 is a front cross-sectional view showing the structure of an internal recirculating pressurized pure oxygen combustor according to an embodiment of the present invention.

2 is a view showing a state in which the exhaust gas circulates in the internal recirculation pressurized pure oxygen combustor according to an embodiment of the present invention.

3 is a view showing a state of controlling the amount of the ceramic ball used in the internal recirculating pressurized oxygen generator according to an embodiment of the present invention.

4 to 6 are diagrams for explaining the structure of a pipe for generating steam in the internal recirculating pressurized oxygen generator according to an embodiment of the present invention.

7 and 8 are the results of measuring the temperature according to the pressure in the process of operating the internal recirculating pressurized oxygen oxygen burner of the present invention.

9 is a result of measuring the amount of nitrogen oxides contained in the exhaust gas generated according to the operating pressure of the internal recirculating pressurized oxygen generator of the present invention.

An embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Internal recirculating pressurized oxygen burner in this embodiment, outer wall 100, burner 200, exhaust 300, inner wall 400, ceramic ball 500, control space 600, vibrator 700 and piping (Not shown in FIG. 1).

The outer wall 100 is a wall constituting the outer surface of the combustor, the flat end surface is circular, and combustion, heat exchange, and steam generation are performed therein.

The burner 200 is configured to form the flame 220 by combustion, and the input pipe 210 into which fuel and oxidant oxygen are introduced is connected.

The exhaust part 300 is a part in which exhaust gas generated by combustion of the burner 200 is discharged to the outside of the combustor.

In the combustor of this embodiment, both the burner 200 and the exhaust part 300 are located at the lower part of the outer wall 100, the burner 200 is located at the center of the lower part of the outer wall 100, and the exhaust part 300 is the burner ( 200). Since the high-temperature exhaust gas generated from the combustion of the burner 200 moves upward, it is not immediately discharged to the exhaust part 300 but circulates inside the combustor, and the exhaust gas rising from the center of the combustor is a side surface of the outer wall 100 After being descended by riding, it is discharged to the exhaust unit 300. Furthermore, the burner 200 and the exhaust unit 300 are located inside the inner wall 400 to be described later, and the movement of the exhaust gas according to this is described in detail later.

The inner wall 400 is formed in the interior of the combustor to divide the space, and the flat cross-section is circular. The inner wall 400 is open at the top, the middle portion 420 is composed of a wall, and the bottom 410 is formed with a through hole to allow exhaust gas to move. At this time, the upper part 430 of the inner wall 400 constitutes a streamlined bottleneck having a diameter of a flat cross-section, thereby inducing a pressure distribution according to the position inside the combustor and configuring the flow of exhaust gas to be smooth. The lower portion 410 may be constructed by punching the wall or attaching a mesh.

Since the inner wall 400 is located close to the burner and the hottest initial exhaust gas is generated and moved, it is preferable to use a material for high temperature of 1300 ° C or higher.

The ceramic ball 500 functions as a heat storage medium for storing heat for a long time under the heat of exhaust gas and a heat transfer medium for transferring heat to water for steam generation. The ceramic ball 500 is located in the space between the outer wall 100 and the inner wall 400, and does not affect the combustion of the burner 200.

The adjustment space 600 is a space located under the outer wall 100 and is configured to store the ceramic ball 500 according to the position of the height adjuster 610. When the height adjuster 610 is lowered to store the ceramic ball 500 in the adjustment space 600, the amount of the ceramic ball 500 positioned between the outer wall 100 and the inner wall 400 is reduced. Through this, even when the flame combusted in the burner 200 is small, even when the thermal energy generated is small, it is possible to prevent the energy from being lost by excessively many ceramic balls 500.

The vibrator 700 is configured to transmit vibration or shock from the outer wall 100 to the inside, so that the movement can be smoothly performed when the ceramic ball 500 is moved.

In the pipe (not shown in FIG. 1), water for generating steam is circulated therein, is located in the space between the outer wall 100 and the inner wall 400, and is arranged to contact the ceramic ball 500. The specific form of the piping will be described in detail later.

Hereinafter, a specific operation and function of the internal recirculating pressurized oxygen oxygen burner according to an embodiment of the present invention will be described.

The exhaust gas generated by the flame 220 of the burner 200 moves upward, and moves upward while being trapped inside the inner wall 400.

The exhaust gas passing through the bottleneck portion of the upper portion 430 of the inner wall 400 and reaching the ceiling of the outer wall 100 descends along the side surface of the outer wall 100. At this time, the exhaust gas descends only through the space between the inner wall 400 and the outer wall 100, and transfers heat to the ceramic balls and pipes located between the inner wall 400 and the outer wall 100.

The exhaust gas descending along the side surface of the outer wall 100 moves to the inside of the inner wall 400 through the lower portion 410 of the inner wall 400, and at this time, some are discharged through the exhaust portion 300 formed downward and some are It rises again along the burner 200 and the flame 220. As the branching of the exhaust gas is generated, a preheating region for preheating fuel and oxidant injected into the burner 200 in a portion indicated by a dotted line is formed.

For the flow and internal recirculation of the exhaust gas, P1, which is the inner space of the inner wall 400, P2, which is the inner space of the outer wall 100, and P3, which is the inner space lower portion of the outer wall 100, and P3, and the inner wall 400, It is necessary to adjust the pressure relationship at the bottom of the space P4. Specifically, the pressure of P1 is the highest and the internal pressure should be gradually lowered in the order of P2, P3, and P4. In this embodiment, the bottleneck section is formed on the upper portion 430 of the inner wall 400 to increase the pressure of P1. In addition, since the exhaust portion 300 is formed in the lower portion of the inner space of the inner wall 400 to discharge a portion of the exhaust gas, the pressure of P4 is made to be the lowest, so that the pressure from P2 to P4 is gradually lowered.

Eventually, the internal recirculating pressurized oxygen oxygen burner according to the embodiment of the present invention does not exhaust all of the exhaust gas and is partially recirculated inside, and the fuel input to the combustor without using a separate external circulation facility or an additional preheating burner. The efficiency can be increased by preheating the oxidizing agent.

When the flame 220 of the burner 200 is small and the heat energy transmitted by the exhaust gas is small, if the amount of the ceramic ball 500 is too large, the heat exchange efficiency with the pipe is caused by heat transfer between the ceramic balls 500. The problem of lowering occurs.

As shown, the internal recirculating pressurized oxygen generator of this embodiment may move the height regulator 610 downward to store the ceramic ball 500 in the regulation space 600. Due to this operation, the amount of the ceramic balls 500 existing between the outer wall 100 and the inner wall 400 is reduced, and it is possible to prevent a problem of heat loss caused by excessive heat transfer between the ceramic balls 500. .

As described above, the vibration of the ceramic ball 500 by the vibrator 700 is applied to the vibration or impact to be smooth.

In this embodiment, the height adjuster 610 is configured to be rotatable along the thread so that the movement of the ceramic ball 500 can be performed naturally. In addition, by placing the packing portion 620 for maintaining the pressure under the control space 600, so as not to affect the internal pressure of the combustor.

Fig. 4 is a front sectional view for explaining the arrangement of the pipe, Fig. 5 is a flat sectional view seen from the direction AA ', and Fig. 6 is a view for explaining the arrangement of the pipe.

Pipes

800 and 900 for generating steam through heat exchange are installed in the space between the outer wall 100 and the inner wall 400, and the shape of the pipe is not particularly limited and various shapes can be applied.

In this embodiment, since the ceramic ball 500 is positioned in the space between the outer wall 100 and the inner wall 400, and the ceramic ball 500 is moved to control the amount of the ceramic ball 500, it includes a moving configuration. , The piping (800, 900) was configured so as not to interfere with the movement of the ceramic ball (500).

In this embodiment, as shown in FIG. 4, two of the outer pipe 800 and the inner pipe 900 are arranged to increase efficiency.

Each pipe (800, 900) is configured to have a long reciprocating structure in the vertical direction to minimize the interference of the pipe when the ceramic ball 500 moves up and down. Specifically, the piping was configured such that the injected heat transfer medium was repeatedly rotated and raised while rotating the inside of the outer wall 100 once, thereby increasing the length of heat transfer and not disturbing the movement of the ceramic ball 500. The heat transfer area was maximized by minimizing the spacing of.

The piping 800 shown in FIG. 6 is wound and arranged between the outer wall 100 and the inner wall 400, and the portion indicated by the dotted line is located between the outer wall 100 and the inner wall 400, so that the injection part ( 810) the water injected into the outer wall 100 and the inner wall 400 is moved up and down along the pipe 800 located between the ceramic ball 500 and the exhaust gas of the surrounding heat to the steam and then exhausted 820.

Hereinafter, the effect of the present invention is confirmed through the operation data of the internal recirculating pressurized pure oxygen combustor manufactured in the structure of FIG. 1.

FIG. 7 uses a fuel mixture of 97% CO and 3% H ₂ , and FIG. 8 uses a fuel mixture of 70% CO and 30% H ₂ , by changing the pressure from 0 bar to 10 bar. The temperature was measured while driving.

The result indicated by T _avg is the average value of the temperatures measured at various parts inside the combustor, and the ranges of the highest and lowest temperatures among the temperatures measured at various parts are indicated at the top of each result. As illustrated, it can be seen that as the operating pressure increases, the temperature inside the combustor decreases as a whole, and the difference between the maximum temperature and the minimum temperature also decreases. From these results, it can be seen that applying the internal recirculating pressurized oxygen burner of the present invention has the effect of reducing the internal temperature gradient.

On the other hand, the result indicated by ΔT _cw is the result of measuring the temperature difference at the inlet and outlet of water used for steam production in the internal recirculating pressurized oxygen generator. As described above, as the pressure increases, the average temperature inside the combustor decreases, but it can be seen that the temperature difference of the injected water is maintained, and it can be seen that the heat transfer efficiency is improved. In this way, the internal recirculating pressurized oxygen generator of the present invention can maintain the steam production efficiency even when the temperature inside the combustor decreases because the operating pressure is high because the heat transfer efficiency is high.

Finally, there is no need to use expensive materials that can withstand relatively high temperatures during the combustor manufacturing process, thereby reducing the cost of combustor manufacturing.

As shown, when the internal recirculating pressurized oxygen-fired combustor of the present invention is applied, it can be confirmed that NO included in exhaust gas decreases as the operating pressure increases. On the other hand, although NO ₂ is generated according to an increase in pressure, it can be seen that the ratio of nitrogen oxides contained in the exhaust gas is preferably adjusted in consideration of the easier treatment of NO ₂ in treating nitrogen oxides.

As a result, since the amount of NO is reduced and NO ₂ is generated, there is an effect of reducing ancillary facilities for nitrogen oxide treatment as compared to the prior art.

The present invention has been described through preferred embodiments, but the above-described embodiments are merely illustrative of the technical idea of the present invention, and various changes are possible within the scope of the present invention. Anyone with ordinary knowledge will understand. Therefore, the protection scope of the present invention should be interpreted by the matters described in the claims, not by specific embodiments, and all technical ideas within the equivalent range should be interpreted as being included in the scope of the present invention.

Claims

outer wall;

An inner wall installed inside the outer wall to divide the inner space;

A burner installed at a lower portion of the outer wall and located at an inner center of the inner wall to burn fuel and oxidant;

An exhaust unit installed at a lower portion of the outer wall, located inside the inner wall, and disposed at the periphery of the burner to discharge exhaust gas to the outside;

A heat-transferring medium used as a solid heat-spherical material located between the outer wall and the inner wall to accumulate heat energy of exhaust gas for heat exchange; And

It is installed between the outer wall and the inner wall and includes a pipe for producing steam through heat exchange,

The inner wall is open at the top and a through hole through which gas can pass is formed at the bottom. Of the exhaust gas moved to the inside of the inner wall, some is discharged through the exhaust portion and the rest is recirculated inside,

An internal recirculating pressurized oxygen burner, characterized by preheating fuel and oxidant injected into the burner by the recirculated exhaust gas.
The method according to claim 1,

The pressure (P1) at the top of the inner space of the inner wall, the pressure (P2) at the top of the inner space of the outer wall, the pressure (P3) at the bottom of the inner space of the outer wall, and the pressure (P4) at the bottom of the inner space of the inner wall ) Is a relationship of P1> P2> P3> P4.
The method according to claim 1,

An internal recirculation pressurized pure oxygen combustor, characterized in that a bottleneck structure in which a space through which exhaust gas passes is narrowed is formed on an upper portion of the inner wall.
The method according to claim 1,

An internal recirculation pressurized pure oxygen combustor, wherein the inner wall is a material for high temperature of 1300 ° C or higher.
The method according to claim 1,

The heat transfer medium is a ceramic ball, the internal recirculation pressurized oxygen oxygen burner further comprising an adjusting means for adjusting the amount of the ceramic ball located between the outer wall and the inner wall.
The method according to claim 5,

The adjustment means is connected to the lower side of the outer wall, the control space for storing the ceramic ball and the amount of ceramic balls stored in the control space can be adjusted by moving the ceramic ball while moving up and down inside the control space. An internal recirculation pressurized pure oxygen combustor comprising a height regulator.
The method according to claim 6,

The height regulator is an internal recirculating pressurized oxygen burner, characterized in that it can move up and down inside the adjustment space through a threaded structure.
The method according to claim 6,

An internal recirculating pressurized oxygen burner further comprising a device that applies vibration or shock from the outside to facilitate movement of the ceramic ball.
The method according to claim 6,

An internal recirculating pressurized oxygen burner, characterized in that a packing part for maintaining pressure is installed at the bottom of the control space.
The method according to claim 6,

The piping is an internal recirculating pressurized oxygen burner, characterized in that the heat exchange medium is arranged to repeat the rise and fall while rotating the inside once.