CN112082150A - Powder preheating gas generator and corresponding powder boiler - Google Patents

Abstract

The invention relates to a powder material preheating gas generator and a corresponding powder material boiler. The existing pulverized coal preheating burner and the corresponding boiler have small operating elastic space. Therefore, the pulverized material preheating gas generator of the present invention includes a preheating combustion chamber, a gas-solid separator and a return material. The preheating combustion chamber The upper part is also provided with a top sealing plate, an enlarged shell and an inverted cone-shaped transition section. The cross-sectional area of the inner cavity of the enlarged shell is ≥ 1.3 times the cross-sectional area of the inner cavity of the fluidized bed, and the height of the expanded shell is ≥ 0.5 meters. The top sealing plate, the expanded shell and the inverted conical tubular transition section form a gas-solid pre-separation chamber above the fluidized bed. An auxiliary gas-solid separator can also be added in the middle section of the gas outlet pipe connected to the gas outlet at the top of the gas-solid separator. The invention has the advantages of large operating elastic space, easy operation and balance, and easy maintenance after balance, and is suitable for various existing industrial boilers, power station boilers and other boilers.

Description

Powder preheating gas generator and corresponding powder boiler

technical field

The invention relates to a powder material preheating gas generator and a corresponding powder material boiler (including a powder material fuel horizontal combustion boiler and a powder material fuel vertical combustion boiler).

Background technique

The Chinese invention patent with the announcement number CN 104791775 B, which was authorized and announced on March 23, 2018, discloses a vertical pulverized coal boiler with a burner at the bottom, and the Chinese utility model with the announcement number CN 204554755 U, authorized and announced on 2015.08.12 The waste heat boiler used in conjunction with it.

The pulverized coal preheating burner disclosed by CN 104791775 B comprises a preheating combustion chamber, a gas-solid separator and a return material connected in sequence, and the three form a circulating fluidized bed type gas generating device. The vertical pulverized coal boiler has the advantages of full combustion, small burden of exhaust gas treatment, high efficiency, energy saving and environmental protection.

The core of the pulverized coal preheating burner is a fluidized bed structure, in which quartz sand is stored as the bottom material of the fluidized bed. After ignition, the hot quartz sand continues to tumble and flow in the preheating combustion chamber, forming countless tumbling and flowing Under the guidance of these fires, the pulverized coal entering the preheating combustion chamber and the oxygen in the primary air and the pulverized air will react rapidly. At the same time, heat is released to further heat the quartz sand, so that the quartz sand keeps tumbling at a high temperature. The generated carbon monoxide, unreacted pulverized coal and part of the quartz sand enter the gas-solid separator. After the quartz sand is separated by the gas-solid separator, it enters the returner through the lower solid outlet, and then returns to the preheating combustion chamber through the returner. , the separated gas such as carbon monoxide (containing a small amount of pulverized coal) enters the vertical boiler from the gas outlet at the top of the gas-solid separator, where it meets the secondary air and tertiary air and is fully burned.

The pulverized coal preheating burner and the corresponding vertical boiler have the advantages of sufficient combustion, high efficiency and environmental protection. This pulverized coal preheating burner and the corresponding vertical boiler have been industrially applied in China, but there are problems such as small operation flexibility, difficulty in establishing the material balance during operation, and difficulty in maintaining the easy-to-run bottom material after the material balance is established. It is currently under continuous improvement.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is how to overcome the small operating elastic space of the existing pulverized coal preheating burner and the corresponding vertical pulverized coal boiler, the difficulty in establishing the material balance during operation, and the difficulty in maintaining and running to the bottom after the material balance is established. In order to solve the defects of raw materials and other defects, provide a powder preheating gas generator and corresponding powder boiler (including powder fuel horizontal combustion boiler and powder fuel vertical combustion boiler) that have large operating flexibility and can maintain material balance for a long time. , in order to improve the safety and reliability of boiler operation.

After a long period of practice and research and demonstration, the inventor found that the internal temperature of the existing pulverized coal preheating burner is as high as 800°C or more, and when the fluidized bed is working, it is not only affected by the primary air and the air flow of the powder supply air, but also by the incomplete pulverized coal. The carbon monoxide air flow produced by combustion is affected. If the air flow is small, the bottom material in the fluidized bed cannot flow effectively to form a material circulation; It is carried into the boiler, resulting in too little bottom material in the fluidized bed of the pulverized coal preheating burner, a sharp drop in the resistance of the primary air and the pulverized air supply, excessive fluctuation of the feed, and unstable operation of the pulverized coal preheating burner. This is the main reason why the existing pulverized coal preheating burners and vertical boilers have small elastic space, it is not easy to establish the material balance during operation, and it is difficult to maintain the easy-running bottom material after the material balance is established.

Based on the above knowledge, the powder preheating gas generator of the present invention includes a preheating combustion chamber, a gas-solid separator and a return feeder, the middle and lower part of the preheating combustion chamber is provided with a fluidized bed structure, and a fluidized bed is stored inside the preheating combustion chamber Bottom material, the bottom of the preheating combustion chamber is in the shape of an inverted cone, the bottom end is connected with the primary air pipe, and the bottom side is connected with the lower port of the returner. The preheating combustion chamber is provided with a powder fuel feed pipe and a fluidized The bed bottom material pipe, the top of the fluidized bed bottom material pipe is provided with a feeding hopper and a feeding valve, the gas-solid separator is a cyclone separator structure, and the gas-solid separator is provided with an inlet, a lower solid outlet and a feeding valve. The gas outlet at the top, the inlet of the gas-solid separator is communicated with the top of the preheating combustion chamber, the solid outlet at the lower part of the gas-solid separator is communicated with the upper outlet of the returner, and the gas outlet at the top of the gas-solid separator is connected with an outlet pipe, which returns The feeder is composed of a section of tortuous pipe, and the tortuous pipe includes a section of inverted U-shaped material sealing pipe. The expanded shell is cylindrical, the outer edge of the top sealing plate is welded on the upper edge of the expanded shell, and the top of the preheating combustion chamber is provided with an air outlet, which communicates with the inlet of the gas-solid separator through the air outlet. , the lower edge of the enlarged shell is welded to the outer edge of the large end of the inverted conical tubular transition section, and the outer edge of the small end of the inverted conical tubular transition section is welded to the side wall of the fluidized bed in the middle and lower part of the preheating combustion chamber. The cross-sectional area is greater than or equal to 1.3 times the cross-sectional area of the inner cavity of the fluidized bed, and the height of the expanded shell is greater than or equal to 0.5 meters. room.

With this structural design, fuel powder and oxygen react at high temperature in the fluidized bed to generate gas. Before entering the gas-solid pre-separation chamber, the gas reaction has ended, and a gas mixture (mainly carbon monoxide and nitrogen) is formed. This part of the gas is mixed The gas is mixed with more bottom material and unburned fuel powder, and enters the gas-solid pre-separation chamber together. According to the principle of fluidics, the cross-sectional area is increased, the flow rate of the gas mixture is greatly reduced, and the density of the gas mixture is greatly reduced. The bottom material and unburned fuel powder entrained by the gas mixture are affected by the blowing force of the gas mixture, and the airflow speed is also greatly reduced. The primary wind and powder feeding wind blow up, so as to keep rolling and flowing.

In this way, on the one hand, the amount of effective bottom material in the fluidized bed is maintained, and the operation of the fluidized bed is more stable; Stable operation of powder preheating gas generator.

As an optimization, it also includes an auxiliary gas-solid separator, the auxiliary gas-solid separator is arranged on the gas outlet pipe, and the auxiliary gas-solid separator includes an enlarged shell, and the cross-sectional area of the inner cavity of the enlarged shell is greater than or equal to the inner cavity of the gas outlet pipe. 1.3 times the cross-sectional area, and the height of the enlarged shell is ≥ 0.5 meters.

In this way, the gas mixture (mainly carbon monoxide and nitrogen) separated from the gas-solid separator passes through the top gas outlet, first enters the gas outlet pipe, and then enters the enlarged shell of the auxiliary gas-solid separator. The area is ≥ 1.3 times the cross-sectional area of the outlet pipe. According to the principle of fluids, the flow rate of the gas mixture is reduced, and the gas density is also greatly reduced. The force is also greatly reduced. This blowing force is not enough to overcome the gravity of the bottom material and unburned fuel powder entrained in the gas mixture. Under the action of gravity, the bottom material and unburned fuel powder fall back to the gas-solid separator. In order to reduce or avoid the problem of unstable operation caused by the loss of bottom material, the fuel powder can also return to the preheating combustion chamber through the gas-solid separator and the return material, and react with oxygen to generate coal gas.

As an optimization, an air outlet groove is provided on the top side wall of the expanded shell, and the top sealing plate and the air outlet groove enclose the air outlet. The expanded shell is cylindrical, the outer edge of the annular top sealing plate is welded on the upper edge of the expanded shell, and the inner edge of the annular top sealing plate is welded on the air outlet pipe above the auxiliary gas-solid separator, The lower edge of the enlarged shell is welded to the outer edge of the large end of the inverted conical tubular transition section, and the outer edge of the small end of the inverted conical tubular transition section is welded to the gas outlet pipe below the auxiliary gas-solid separator. With this design, the structure is simple, the welding is convenient, and at the same time, the bottom material separated from the enlarged shell is more likely to fall back to the gas-solid separator under the guidance of the inverted conical tubular transition section.

The powder material preheating gas generator has good heat storage characteristics, anthracite coal that cannot be burned in conventional pulverized coal boilers, dry powder of coal washing sludge in coal preparation plant, blue carbon powder with low volatile content or gasifier ash slag Or semi-coke powder or other powdery solid waste with a certain calorific value can be stably burned in the powder preheating gas generator and its boiler.

By introducing a gas-solid pre-separation chamber and/or an auxiliary gas-solid separator, the present invention greatly improves the operation flexibility and stability of the powder preheating burner, thereby improving the horizontal The overall safety and reliability of the combustion boiler or pulverized fuel vertical combustion boiler system.

The powder material preheating gas generator of the invention is coupled and connected with the horizontal powder fuel boiler or the vertical powder fuel boiler. The bottom material amount and powder fuel feeding amount of the powder preheating gas generator match the capacity of the horizontal powder fuel boiler or the vertical powder fuel boiler and the characteristics of the powder fuel used.

The powder horizontal combustion boiler of the present invention includes a horizontal boiler body, one end of the horizontal boiler body is a feed end, the feed end is provided with a feed port, and the other end is provided with a tail flue, characterized in that: the horizontal boiler body is characterized in that: There is a secondary air box in the center of the side wall of the feed end of the boiler body. The outside of the secondary air box is communicated with the secondary air pipe. The interior of the horizontal boiler body is provided with a plurality of secondary air nozzles that communicate with the secondary air box. The mouth is connected with the aforesaid powder preheating gas generator. With this design, through the gas-solid pre-separation chamber and/or the auxiliary gas-solid separator, the operation flexibility of the powder preheating burner is improved, making it easier to balance the horizontal boiler during operation, and to maintain the balance more easily.

As an optimization, a plurality of combustion air ducts are arranged on the side wall of the horizontal boiler body, and the above combustion air ducts are evenly distributed on the horizontal boiler body. There is a dedicated combustion fan (or called a tertiary fan) on the air main pipe, or the combustion air main pipe is led out from the secondary air duct main pipe or the secondary air box. This design ensures sufficient combustion, less harmful substances in the exhaust, energy saving and environmental protection.

The powder vertical combustion boiler of the present invention includes a vertical boiler body, the lower end of the vertical boiler body is a feed end, and the feed end is provided with a feed port, and is characterized in that: the feed port of the vertical boiler body is connected to There is the aforementioned powder preheating gas generator.

The pulverized material preheating gas generator and the corresponding pulverized material boiler of the present invention have large operating elastic space, are easy to operate in balance, and are easy to maintain after the balance. In addition to the bituminous coal used in conventional pulverized coal boilers, it can also stably burn anthracite, The coal preparation plant is used to wash and select dry coal powder, blue carbon powder, gasifier ash, semi-coke powder, or other powdery solid waste with a certain calorific value. It is suitable for various existing industrial boilers, power station boilers and other boilers. use.

Description of drawings

Below in conjunction with accompanying drawing, the powder material preheating gas generator of the present invention and the corresponding powder material boiler are further described:

Fig. 1 is the schematic diagram of the first embodiment of this powder preheating gas generator (the arrow direction in the figure is the falling direction of quartz sand);

Fig. 2 is the schematic diagram of the second embodiment of this powder preheating gas generator (the arrow direction in the figure is the falling direction of quartz sand);

Fig. 3 is the schematic diagram of the third and fourth embodiments of the powder horizontal boiler;

Figure 4 is a schematic diagram of an embodiment of the present pulverized fuel vertical boiler.

In the figure: 1 is the preheating combustion chamber, 11 is the fluidized bed, 2 is the gas-solid separator, 3 is the return material, 31 is the inverted U-shaped material sealing tube, 4 is the fluidized bed bottom material, and 5 is the primary air Pipe, 6 is the fuel powder feeding pipe, 7 is the feeding pipe, 8 is the feeding hopper, 9 is the feeding valve, 10 is the gas outlet pipe, 12 is the auxiliary gas-solid separator, 121 is the expansion shell, and 122 is the annular top sealing plate , 123 is the inverted conical tubular transition section, 124 is the air outlet, 13 is the top sealing plate, 14 is the gas-solid pre-separation chamber, 15 is the horizontal boiler body, 16 is the tail flue, 17 is the secondary air box, 18 is the The secondary air duct, 19 is the secondary air nozzle, 20 is the burning air duct, and 21 is the vertical boiler body.

Detailed ways

Embodiment 1: As shown in FIG. 1 , the powder preheating gas generator of the present invention includes a preheating combustion chamber 1, a gas-solid separator 2 and a return material 3, and the middle and lower part of the preheating combustion chamber 1 is provided with a fluidized The bed 11 has a structure in which the fluidized bed bottom material 4 is stored inside, the bottom of the preheating combustion chamber 1 is in the shape of an inverted cone, the bottom end is communicated with the primary air duct 5, and the bottom side is communicated with the lower port of the returner 3. The preheating combustion chamber 1 is provided with a powder fuel feed pipe 6 and a fluidized bed bottom material pipe 7. The top of the fluidized bed bottom material pipe 7 is provided with a feeding hopper 8 and a feeding valve 9. The separator 2 is a cyclone separator structure, the gas-solid separator 2 is provided with an inlet, a lower solid outlet and a top gas outlet, the inlet of the gas-solid separator 2 is communicated with the top of the preheating combustion chamber 1, and the gas-solid separator 2 is 2. The lower solid outlet is communicated with the upper port of the returner 3. The gas outlet at the top of the gas-solid separator 2 is connected with a gas outlet pipe 10. The returner 3 is composed of a section of tortuous pipe, and the tortuous pipe includes a section of inverted U-shaped material sealing pipe 31 , which is characterized in that: the upper part of the preheating combustion chamber 1 is also provided with a top sealing plate 13, an enlarged casing 121 and an inverted conical tubular transition section 123, the enlarged casing 121 is cylindrical, and the top sealing plate is 13. The outer edge is welded on the upper edge of the expanded shell 121. The top of the preheating combustion chamber 1 is provided with an air outlet, which is communicated with the inlet of the gas-solid separator 2 through the air outlet. The lower edge of the expanded shell 121 is welded on the inverted The outer edge of the large end of the conical tubular transition section 123 is welded on the outer edge of the small end of the inverted conical tubular transition section 123 on the side wall of the fluidized bed 11 in the middle and lower part of the preheating combustion chamber 1. The inner cavity of the enlarged shell 121 The cross-sectional area is greater than or equal to 1.3 times the cross-sectional area of the inner cavity of the fluidized bed 11, and the height of the expanded shell 121 is greater than or equal to 0.5 meters. A gas-solid pre-separation chamber 14 is formed above 11 .

Embodiment 2: As shown in FIG. 2 , it further includes an auxiliary gas-solid separator 12, the auxiliary gas-solid separator 12 is arranged on the gas outlet pipe 10, the auxiliary gas-solid separator 12 includes an expanded shell 121, and the auxiliary gas-solid separator 12 The cross-sectional area of the inner cavity of the expanded housing 121 is greater than or equal to 1.3 times the cross-sectional area of the inner cavity of the air outlet pipe 10, and the height of the expanded housing 121 is greater than or equal to 0.5 meters.

The top side wall of the expanded shell 121 is provided with an air outlet groove 124, and the top sealing plate 13 and the air outlet groove 124 enclose the air outlet. In the transition section 123, the expanded shell 121 is cylindrical, the outer edge of the annular top sealing plate 122 is welded to the upper edge of the expanded shell 121, and the inner edge of the annular top sealing plate 122 is welded to the auxiliary gas-solid On the air outlet pipe 10 above the separator 12, the lower edge of the enlarged shell 121 is welded to the outer edge of the large end of the inverted conical tubular transition section 123, and the outer edge of the small end of the inverted conical tubular transition section 123 is welded to the auxiliary gas-solid separation. On the outlet pipe 10 below the device 12. The rest of the structure is shown in Embodiment 1, which is omitted.

Embodiment 3: As shown in FIG. 3, the powder horizontal combustion boiler of the present invention includes a horizontal boiler body 15, one end of the horizontal boiler body 15 is a feed end, the feed end is provided with a feed port, and the other end is provided with a feed port. The tail flue 16 is characterized in that: the center of the side wall of the feed end of the horizontal boiler body 15 is provided with a secondary air box 17, the outside of the secondary air box 17 is communicated with the secondary air pipe 18, and the interior of the horizontal boiler body 15 A plurality of secondary air nozzles 19 communicated with the secondary air box 17 are provided, and the feed inlet is connected with the powder preheating gas generator described in Embodiment 1 or 2, which is omitted.

Embodiment 4: As shown in FIG. 3 , a plurality of burning ember air ducts 20 are arranged on the side wall of the horizontal boiler body 15, and the above-mentioned burning ember air ducts 20 are evenly distributed on the horizontal boiler body 15. The pipes 20 are all communicated with the combustion air main pipe (not shown in the figure), and the combustion air main pipe is provided with a dedicated combustion air fan (or called a tertiary fan) (not shown in the figure) or the combustion air main pipe from the second. The secondary air main pipe or the secondary air box is led out, and the rest of the structure is as shown in the third embodiment, which is omitted.

Embodiment 5: The powder vertical combustion boiler of the present invention includes a vertical boiler body 21, the lower end of the vertical boiler body 21 is a feeding end, and the feeding end is provided with a feeding port, characterized in that: the vertical boiler The feed port of the main body 21 is connected with the powder preheating gas generator described in Embodiment 1 or 2, as shown in FIG. 4 . Of course, the fuel inlet of the vertical combustion boiler body 21 can also be introduced from both sides of the furnace, and the drawing is omitted.

The present invention includes but is not limited to the above-mentioned embodiments, and any device that meets the description in the claims of the present invention falls within the protection scope of the present invention.

Claims (6)

1. A powder preheating gas generator, comprising a preheating combustion chamber, a gas-solid separator and a feeder, the middle and lower part of the preheating combustion chamber is provided with a fluidized bed structure, and the bottom of the fluidized bed is stored inside. The bottom of the preheating combustion chamber is in the shape of an inverted cone, the bottom end of which is communicated with the primary air pipe, and the bottom side is communicated with the lower port of the return feeder. The preheating combustion chamber is provided with a powder fuel feed pipe and a fluidized bed. Bottom material pipe, the top of the fluidized bed bottom material pipe is provided with a feeding hopper and a feeding valve, the gas-solid separator is a cyclone separator structure, and the gas-solid separator is provided with an inlet, a lower solid outlet and a top The gas outlet, the inlet of the gas-solid separator is communicated with the top of the preheating combustion chamber, the solid outlet at the lower part of the gas-solid separator is communicated with the upper outlet of the returner, and the gas outlet at the top of the gas-solid separator is connected with an outlet pipe, and the material is returned. The device consists of a section of tortuous pipe, and the tortuous pipe includes a section of inverted U-shaped material sealing pipe. The expanded shell is cylindrical, the outer edge of the top sealing plate is welded on the upper edge of the expanded shell, and the top of the preheating combustion chamber is provided with an air outlet, which is communicated with the inlet of the gas-solid separator through the air outlet. The lower edge of the enlarged shell is welded to the outer edge of the large end of the inverted conical tubular transition section, and the outer edge of the small end of the inverted conical tubular transition section is welded to the side wall of the fluidized bed in the middle and lower part of the preheating combustion chamber. The area is greater than or equal to 1.3 times the cross-sectional area of the inner cavity of the fluidized bed, and the height of the expanded shell is greater than or equal to 0.5 meters. The top sealing plate, the expanded shell and the inverted conical tubular transition section form a gas-solid pre-separation chamber above the fluidized bed . 2. The powder preheating gas generator according to claim 1, characterized in that: it further comprises an auxiliary gas-solid separator, the auxiliary gas-solid separator is arranged on the gas outlet pipe, and the auxiliary gas-solid separator is Including an enlarged shell, the cross-sectional area of the inner cavity of the enlarged shell is greater than or equal to 1.3 times the cross-sectional area of the inner cavity of the outlet pipe, and the height of the expanded shell is greater than or equal to 0.5 meters. 3. The powder material preheating gas generator according to claim 1, characterized in that: the top side wall of the expanded shell is provided with an air outlet groove, the top sealing plate and the air outlet groove enclose the air outlet, and the auxiliary The gas-solid separator also includes an annular top sealing plate and an inverted conical tubular transition section, the expanded shell is cylindrical, the outer edge of the annular top sealing plate is welded on the upper edge of the expanded shell, and the annular The inner edge of the top sealing plate is welded to the air outlet pipe above the auxiliary gas-solid separator, the lower edge of the enlarged shell is welded to the outer edge of the large end of the inverted conical tubular transition section, and the outer edge of the small end of the inverted conical tubular transition section is welded to the auxiliary gas-solid on the outlet pipe below the separator. 4. A powder material horizontal combustion boiler, comprising a horizontal boiler body, one end of the horizontal boiler body is a feed end, the feed end is provided with a feed port, and the other end is provided with a tail flue, characterized in that: The center of the side wall of the feed end of the horizontal boiler body is provided with a secondary air box, the outside of the secondary air box is communicated with the secondary air pipe, and the interior of the horizontal boiler body is provided with a plurality of secondary air nozzles communicated with the secondary air box, The feed port is connected with the powder material preheating gas generator according to claim 1, 2 or 3. 5. The powder material horizontal boiler according to claim 4, characterized in that: the side wall of the horizontal boiler body is provided with a plurality of burning ember air ducts, and the above burning ember air ducts are evenly distributed on the horizontal boiler body , All the burning air pipes are connected with the burning burning air main pipe. There is a special burning burning fan on the burning burning air main pipe, or the burning burning air main pipe is led out from the secondary air duct main pipe or the secondary air box. 6. A powder vertical combustion boiler, comprising a vertical boiler body, the lower end of the vertical boiler body is a feeding end, and the feeding end is provided with a feeding port, characterized in that: the feeding of the vertical boiler body The mouth is connected with the powder material preheating gas generator according to claim 1 or 2 or 3.

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