CN110631871A - A device and method for collecting ash from a sealed piston type pressurized boiler - Google Patents

Abstract

The invention discloses a dust-taking device and method for a sealed piston type pressurized boiler. The device includes a pressure vessel, an inlet pipeline is arranged at the upper end of the pressure vessel, an air charging valve is arranged on one side, and a flue gas outlet pipeline is arranged on the other side. There is an ash outlet pipeline at the lower end, and a sealing piston inside. Inert gas is filled into the pressure vessel through the inflation valve, so that the internal pressure before the ash collection device works is equal to the flue pressure. The invention has the advantages of good sealing performance, high ash extraction efficiency and easy maintenance. This ash extraction method can solve the problems of flying ash splashing caused by the pressure difference between the inside and outside of the ash extraction point, the reduction of ash collection and the environmental pollution caused by the leakage of flue gas. The destruction of the field structure, so as to realize the safe and efficient ash removal from the high-pressure flue.

Description

A device and method for collecting ash from a sealed piston type pressurized boiler

technical field

The invention relates to an ash-taking device and method, in particular to a sealed-piston pressurized boiler ash-taking device and method, and belongs to the field of boiler ash-taking devices.

Background technique

The basic pattern of primary energy dominated by coal is difficult to change in the short term, and the clean and efficient utilization of coal is still an important technical issue for the development of energy transformation. In thermal power plants, fly ash is an important part of boiler tail flue gas. Its physical and chemical analysis results are of great significance to power plant operation regulation, cost control, design transformation and environmental protection. Pressurized combustion has the advantages of increasing the combustion rate of coal particles, improving combustion efficiency, and reducing the emission of NO pollutants. Integrated coal gasification combined cycle and pressurized oxyfuel combustion technologies both involve pressurized gasification/combustion processes.

Although increasing the reaction pressure has many advantages, the pressurized condition increases the difficulty of ash extraction and puts forward higher requirements for the ash extraction device. During the process of collecting ash, due to the huge pressure difference between the inside and outside of the ash collection point, the ash sample will often spew out with the high-pressure flue gas, which not only reduces the amount of ash collection, reduces the efficiency of ash collection, but also pollutes the environment. At present, most of the ash extraction devices are suitable for atmospheric boilers, and are not suitable for ash extraction under pressurized conditions. More importantly, these devices will have a huge impact on the internal pressure of the flue during the ash removal process, thereby destroying the flue gas flow structure inside the flue. In addition, some ash collection devices are used to deal with continuous ash discharge and a large amount of ash. The system structure is complex, the manufacturing process is difficult and costly, and the ash sample cannot be collected conveniently and quickly in a short time. Work.

Contents of the invention

Purpose of the invention: The present invention provides a device and method for collecting ash in a high-pressure flue that is safe, efficient, and environmentally friendly, so as to solve the above problems.

Technical solution: The ash extraction device for a sealed piston type pressurized boiler of the present invention includes a pressure vessel, the upper end of the pressure vessel is provided with an inlet pipeline, one side is provided with an inflation valve, the other side is provided with a flue gas outlet pipeline, and the lower end is provided with an inlet pipeline. An ash outlet pipeline is provided, and a sealing piston is arranged inside; the sealing piston is moved up and down by adjusting the piston control part, and is used for isolating the collected fly ash.

Preferably, the pressure vessel is divided into multiple sections, and each section can be connected by a flange.

When the sealing piston descends to the end, its peripheral side is in sealing contact with the inner wall of the pressure vessel.

The sealing piston is in the shape of a platform, a cone or a truncated cone.

A sampling valve is provided on the inlet pipeline.

An induced draft fan and a flue gas outlet valve are arranged on the flue gas outlet pipeline.

An ash discharge valve is arranged on the ash outlet pipeline.

The front part of the ash discharge valve is provided with a rotor, and the rotor is connected to the transmission and the motor. Preferably, the rotor can be a star rotor.

A differential pressure gauge is provided between the flue and the pressure vessel.

A method for collecting ash from a sealed piston type pressurized boiler ash collection device, comprising the following steps:

a. Close all valves, connect the device inlet pipeline to the flue sampling port, and connect the flue gas outlet pipeline to the flue gas sampling port;

b. Open the inflation valve and fill the pressure vessel with inert gas until the pressure in the vessel is the same as that of the flue;

c. Close the inflation valve, open the valves on the inlet pipeline and the flue gas outlet pipeline, and the flue gas carrying fly ash enters the pressure vessel and returns to the flue through the flue gas outlet pipeline. At this time, the sealing piston is separated from the wall;

d. After the collection is completed, close the valves on the inlet pipeline and the flue gas outlet pipeline, and move the sealing piston down through the piston control unit until it is closely attached to the wall of the pressure vessel;

e. Open the valve on the ash outlet pipeline to discharge the deposited fly ash.

The following steps can also be implemented before the step e:

f. Open the valve on the flue gas outlet pipeline to discharge the high-pressure flue gas in the space above the sealed piston out of the pressure vessel.

g. When the pressure difference between the flue and the pressure vessel is stable, close the valve on the flue gas outlet pipeline and move up the sealing piston, so that the high-pressure gas on the lower side of the sealing piston enters the upper normal pressure space again. This step is used to release the high-pressure fumes remaining in the lower part of the piston.

When the flue gas outlet pipeline of the ash collecting device is provided with an induced draft fan, the induced draft fan is turned off while implementing step b, and turned on while implementing step c.

Beneficial effect: compared with the prior art, the present invention has the following significant advantages:

(1) The invention realizes the separation of fly ash and flue gas and the work of flue gas pressure relief conveniently, quickly and reliably, and effectively prevents fly ash from flying ash due to excessive pressure difference between the inside and outside of the ash collection device, Problems such as reducing the amount of dust collected.

(2) The present invention can complete the ash removal process without changing the internal flow structure of the high-pressure flue. At the same time, the extracted flue gas is returned to the flue again, which avoids environmental pollution caused by flue gas leakage.

(3) The present invention can effectively reduce the residual fly ash in the pressure vessel and improve the collection rate of the fly ash by filling and discharging the inert gas during the ash collection process.

(4) The rotor provided in the present invention can control the discharge rate of fly ash through an external motor and transmission. At the same time, the rotor itself has good sealing performance, which can prevent the leakage of fly ash caused by unbalanced pressure difference under unexpected circumstances.

(5) The segmented design of the pressure vessel of the present invention can effectively simplify the disassembly and assembly process and facilitate the inspection and maintenance of its internal components. Especially when the boiler burns low-quality coal with high ash and high sulfur, a large amount of fly ash is likely to cause certain damage to the internal components of the ash collection device. At this time, the convenient and quick disassembly design is particularly important.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 (a) is the schematic diagram of the separation state of the sealing piston and the container wall of the present invention;

Fig. 2 (b) is the schematic diagram of sealing state of sealing piston and container wall surface of the present invention;

Figure 3 is a structural diagram of sealing pistons with different shapes.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , a sealed piston type supercharged boiler ash extraction device includes a pressure vessel 2 , an inlet pipe 15 , a flue gas outlet pipe 11 and an ash outlet pipe 11 . The wall of the pressure vessel 2 is provided with an inflation valve 5 and an exhaust valve 6, the other side is provided with a flue gas outlet pipeline 11, the top is provided with an inlet pipeline 15, the bottom is provided with an ash outlet pipeline 16, and the inside is provided with a sealing piston 3. The pressure vessel 2 can be divided into multiple sections, and each section is connected by a flange, which is convenient for inspection and maintenance of the inside of the device. A sampling valve 13 is provided on the inlet pipeline. An induced draft fan 12 and a flue gas outlet valve 13 are arranged on the flue gas outlet pipeline. An ash discharge valve 10 is arranged on the ash outlet pipeline. A differential pressure gauge 14 is provided between the flue and the pressure vessel 2 .

The sealing piston 3 can be moved up and down by adjusting the piston control member 4 to isolate the collected fly ash. According to the cohesiveness of the collected ash sample, the sealing piston 3 can adopt different shapes, and the sealing piston can be platform-shaped, conical or truncated-conical, as shown in Fig. 3 . The platform type piston has the simplest structure and the lightest mass, but the ash is also the easiest to deposit on the surface; the conical piston structure has a complex mass, but the least ash accumulation; the truncated cone type piston is in between.

As shown in Figure 2(a), when the sealing piston 3 is separated from the wall of the pressure vessel 3, the lower space of the piston communicates with the upper space, and the ash falls to the lower space in the pressure vessel 2 under the action of gravity. When the sealing piston falls to the end, the pressure vessel is divided into two isolated spaces, and the ash is pressed in the lower part of the pressure vessel 3 and the ash outlet pipeline 11, as shown in Fig. 2(b). The outer side of the sealing piston 3 may be provided with a high temperature resistant sealing rubber ring.

The upper part of the ash discharge valve is provided with a rotor 9, which is connected to the transmission 8 and the motor 7, and under the action of the transmission 8 and the motor 7, the rotation speed of itself is adjusted to control the ash discharge rate. The rotor can block the fly ash, and protect the fly ash leakage problem caused by the imbalance of internal and external pressure of the ash collection device under special circumstances. The gap between the outer side of the rotor 9 and the wall of the pressure vessel is less than 1 mm, and the rotor 9 can also be a star-shaped rotor, which has good sealing performance.

Example 1

The ash-taking method of the present invention is described in detail with embodiment 1, comprises the following steps:

a. Close all valves (injection valve 1, inflation valve 5, exhaust valve 6, ash discharge valve 10 and flue gas outlet valve 13), connect the device inlet pipeline 15 to the flue gas sampling port A, and connect the flue gas outlet Pipeline 11 to flue sample outlet B.

b. Open the inflation valve 5, and fill inert gas into the pressure vessel 2 through the inflation valve 5 until the pressure in the pressure vessel 2 is the same as the flue pressure, and the differential pressure gauge 14 shows 0 at this time. The inert gas can also have a certain pressure. The pressure of the ash extraction device is the same as that of the flue, and the flow field distribution inside the flue will not be affected during the ash extraction process.

c, close the inflation valve 5, open the valve (injection valve 1, flue gas outlet valve 13) and the induced draft fan 12 on the inlet pipeline 15, the flue gas outlet pipeline 11, the flue gas that carries fly ash enters the pressure vessel 2, and Back to the flue through the flue gas outlet pipeline 11, the charging valve 5, exhaust valve 6, and ash discharge valve 10 are all closed, and the sealing piston 3 is separated from the wall of the pressure vessel 2.

d. After a certain period of time, when the inert gas in the pressure vessel 2 and the flue gas outlet pipeline 11 has all turned into flue gas, close the valves on the inlet pipeline and the flue gas outlet pipeline 11 (injection valve 1, flue gas outlet valve 13) With the induced draft fan 12, the sealing piston 3 is moved down through the piston control part 4 until it is closely attached to the wall of the pressure vessel. Due to the effect of gravity, most of the fly ash is deposited in the space below the sealing piston.

e. Open the flue gas outlet valve 13 and the induced draft fan 12 on the flue gas outlet pipeline 11, and discharge the high-pressure flue gas in the upper side space of the sealing piston 3 out of the pressure vessel.

f. When the pressure difference between the flue and the pressure vessel is stable, close the upper flue gas outlet valve 13 and the induced draft fan 12 on the flue gas outlet pipeline 11, and move up the sealing piston 3 so that the high pressure on the lower side of the previous sealing piston The gas enters the upper normal-pressure space again. Since the volume of the upper space is much larger than the volume of the lower space, after one or two pressure relief processes, the inside of the pressure vessel can become normal pressure, and the fly ash still remains inside the container without carried out by the gas.

g. Open the valve on the ash outlet pipeline 16, and adjust the speed of the rotor 9 through the transmission 8 and the motor 7 to discharge the deposited fly ash. After the ash removal is completed, when there is fly ash remaining in the pressure vessel 2, open the inflation valve 5, the exhaust valve 6 and the ash discharge valve 10 (other valves are closed), and the gas can be injected into the pressure vessel 2 through the inflation valve 5. Purge it with inert gas, and repeat the above process so that the residual fly ash is discharged through the rotor 9 and the ash discharge valve 10.

Claims (8)

1. The ash taking device for the sealed piston type supercharged boiler is characterized by comprising a pressure container (2), wherein an inlet pipeline (15) is arranged at the upper end of the pressure container (2), an inflation valve (5) is arranged at one side of the pressure container, a flue gas outlet pipeline (11) is arranged at the other side of the pressure container, an ash outlet pipeline (16) is arranged at the lower end of the pressure container, and a sealed piston (3) is arranged inside the pressure container; the sealing piston (3) moves up and down through the adjusting piston control piece (4).

2. The ash extraction device of a sealed piston supercharged boiler according to claim 1, characterized in that the peripheral side of the sealing piston (3) is in sealing abutment with the inner wall of the pressure vessel (2) when it is lowered to the end.

3. The ash extraction device of a sealed piston supercharged boiler according to claim 1, characterized in that the sealing piston (3) is platform-shaped, conical or truncated cone-shaped.

4. The ash extraction device of the sealed piston type supercharged boiler according to claim 1, characterized in that an induced draft fan (12) and a flue gas outlet valve (13) are arranged on the flue gas outlet pipeline (11).

5. The ash extraction device of a sealed piston type supercharged boiler according to claim 1, characterized in that the ash outlet line (16) is provided with a rotor (9) and an ash valve (10), the rotor connecting the transmission (8) and the motor (7).

6. The ash taking method of the ash taking device of the sealed piston type supercharged boiler based on the claim 1 is characterized by comprising the following steps:

a. closing all valves, connecting the device inlet pipeline to a flue sampling port, and connecting a flue gas outlet pipeline to a flue sample outlet;

b. opening the charging valve (5), and charging inert gas into the pressure container (2) until the pressure in the container is the same as the pressure in the flue;

c. closing the charging valve (5), opening valves on the inlet pipeline and the flue gas outlet pipeline, allowing the flue gas carrying the fly ash to enter the pressure container and return to the flue through the flue gas outlet pipeline (11), and separating the sealing piston (3) from the wall surface;

d. after the collection is finished, the valves on the inlet pipeline and the flue gas outlet pipeline are closed, and the sealing piston (3) is moved downwards through the piston control part (4) until the sealing piston is tightly attached to the wall surface of the pressure vessel;

e. and opening a valve on an ash outlet pipeline to discharge the deposited fly ash.

7. The supercharged boiler ash-removing method according to claim 6, wherein said step e is preceded by the steps of:

f. opening a valve on a flue gas outlet pipeline, and discharging high-pressure flue gas in the upper side space of the sealing piston (3) out of the pressure container;

g. and when the pressure difference between the flue and the pressure container is stable, closing the valve on the flue gas outlet pipeline and moving the sealing piston (3) upwards, so that the high-pressure gas on the lower side of the sealing piston (3) enters the upper normal-pressure space again.

8. The supercharged boiler ash taking method according to claim 6, wherein when an induced draft fan (12) is arranged on the flue gas outlet pipeline (11) of the ash taking device, the induced draft fan is turned off while the step b is implemented, and the induced draft fan is turned on while the step c is implemented.

Images