CN114060845A

CN114060845A - Anti-blocking type air preheater with purging function, intelligent control and middle soot blower

Info

Publication number: CN114060845A
Application number: CN202111579772.1A
Authority: CN
Inventors: 益晓斌; 白文辉
Original assignee: Xi'an Meikesen Technology Engineering Co ltd
Current assignee: Xi'an Meikesen Technology Engineering Co ltd
Priority date: 2021-12-22
Filing date: 2021-12-22
Publication date: 2022-02-18

Abstract

The invention discloses an anti-blocking air preheater with a purging function, intelligent control and a soot blower additionally arranged in the middle, wherein the soot blower is additionally arranged in a rotor heat transfer element of the air preheater, so that the purging effect of a soot blowing system of the air preheater is greatly improved; an ultrasonic generator is additionally arranged on a high-temperature steam inlet pipeline of a soot blower of the air preheater, so that the soot blower has a blowing and blocking function during operation, simultaneously certain heat exchange element surface dirt is stripped, and steam soot blowing also has a cleaning function; the blocking condition of the heat transfer element in each bin of the air preheater is accurately monitored; the intelligent digital air preheater monitoring and control system accurately controls the distribution conditions of temperature, pressure and flow field in the warehouse area and monitors the surface dust deposition and dust deposition trend analysis of the heat exchange elements. The invention can be fully suitable for the pulverized coal boiler with the SCR denitration system, can replace the traditional rotary air preheater, and solves the problem of frequent blockage of the heat transfer element after the pulverized coal boiler is subjected to denitration.

Description

Anti-blocking type air preheater with purging function, intelligent control and middle soot blower

Technical Field

The invention relates to the technical field of boilers, in particular to important equipment for reducing the exhaust gas temperature, improving the air supply temperature and realizing energy conservation and emission reduction of a boiler. The invention can be fully suitable for the pulverized coal fired boiler provided with the SCR denitration system, can replace the traditional rotary air preheater, and solves the problem of frequent blockage of the heat transfer element after the pulverized coal fired boiler is subjected to denitration.

Background

With the continuous improvement of the national requirements for environmental protection, the emission index of NOx (nitrogen oxide) in a boiler is lower and lower, and the formation of an ABS (ammonium bisulfate) product cannot be avoided no matter SCR or SNCR denitration mode is adopted. ABS products can be condensed at a certain temperature, the ABS products can be condensed from a gas state to a liquid state below 220 ℃, and the ABS products can be condensed from the liquid state to a solid state below 148 ℃, so that the operation performance of subsequent equipment is influenced negatively. The most severely affected equipment is the air preheater, especially the rotary air preheater, behind it. It is affected the most because it is a heat exchange device with a large difference between inlet and outlet ends. The temperature difference of the smoke temperature side of the device basically works in the range of 400-120 ℃. The boiler is important equipment for reducing the exhaust gas temperature, improving the air supply temperature and realizing energy conservation and emission reduction. In this temperature range, it is also the process of condensing the denitrated product ABS from a gaseous state into a solid sludge. A large amount of solid condensate adheres with high adhesive strength to the heat exchanger plates, i.e., the heat transfer elements, of the air preheater. The continuous increase of the adhesion thickness can block the through-flow section of the heat exchange sheet, so that the resistance of a flue and an air duct is continuously increased, and the air supply and the smoke discharge of the boiler are influenced. The light causes the unit to run with reduced load, and the heavy is forced to stop running.

In order to solve the problem of blockage of the air preheater (short for air preheater), three approaches are commonly adopted at present:

1. by adjusting the boiler combustion, the combustion performance is optimized, and ABS production is reduced as much as possible.

2. The cross section of a flow channel in the heat transfer element of the rotary air preheater is increased, so that the resistance of the flow channel is reduced, and the passing performance of smoke and wind is enhanced. Meanwhile, a certain favorable condition is provided for adopting a third way.

3. And a mechanical cleaning method is adopted, so that the ABS condensed and adhered to the inner surface of the heat transfer element is removed.

However, the above three approaches have proved to be very limited in effect. Firstly, the combustion adjustment of the boiler is optimized, and the ABS condensate cannot be fundamentally prevented from being generated; the flow channel of the element is enlarged, the surface area of the heat transfer element is reduced, heat exchange is not facilitated, the air temperature is reduced, the exhaust gas temperature is increased, and certain economical efficiency of equipment is sacrificed; the rotary air preheater element is too thick and difficult to wash through, and ABS stickies adhered to the middle section inside the element cannot be removed on line by adopting steam or high-pressure water.

For the reasons, the problem of blockage of the heat transfer element of the air preheater is an important problem which is difficult to completely solve by the pulverized coal boiler of the power station at present. And the present invention is also proposed for this purpose.

Disclosure of Invention

In order to meet the requirements, the invention aims to solve the problem of frequent blockage of a heat transfer element after denitration of a pulverized coal boiler by adopting an anti-blocking rotary air preheater with a purging function, an intelligent monitoring and control system and a soot blower additionally arranged in a rotor.

The technical method adopted by the invention to achieve the aim is as follows:

under the condition of ensuring that the original heat transfer efficiency of the original rotary air preheater (traditional) is not changed, the height positions of the heat transfer elements in the bins are rearranged, a layer of space is reserved in the rotor elements, and the soot blowers are additionally installed.

A rod soot blower is additionally arranged in the space reserved in each partition bin. The number of the soot blowers is the same as that of the bins of the air preheater.

The front end of the soot blowing gun in each bin lattice is provided with a vector spray head capable of changing the blowing direction, and the spray head can provide power for enabling the soot blowing gun to swing in a sector mode, so that the soot blowing gun can sweep in a full-coverage mode in a sector through-flow section. The soot blower arrangement position is in the ABS concentrated forming stage, and can be used for performing key purging on a blockage concentrated area between sections.

The high-temperature steam inlet pipeline of the soot blower of the air preheater is additionally provided with an ultrasonic generator with a confidential technology, so that the soot blower has a blowing and blocking function during operation, and simultaneously utilizes the cavitation action of ultrasonic waves in a medium to achieve certain surface dirt peeling of a heat exchange element, so that the steam soot blower has a cleaning function, and finally, no dust is accumulated on the surface of a heat exchange element, and ABS crystals cannot be adhered to the surface of the heat exchange element.

An arranged sootblower gas (steam) source is introduced through the rotor central barrel and then connected to the distribution header to which each sootblower is coupled by a rotary joint and an angle valve. The opening of each angle valve is completed by the action of an actuator arranged outside the air preheater, and the actuator penetrates into the air preheater through a telescopic rod to trigger the corresponding angle valve, so that the angle valve is opened. Through the cooperation of the angular speed of the rotor of the air preheater and the action time of the actuator, any one angle valve can be opened, so that the accurate soot blowing action is realized.

In order to realize accurate soot blowing of the soot blower and avoid the problems of over-blowing and under-blowing, the array flow field sensor group is additionally arranged on the airflow channel of the air preheater and used for feeding back the uniformity of the airflow field passed by the air preheater so as to judge the blockage condition of the elements of the air preheater, and the soot blower is controlled by a program according to the blockage condition, so that intelligent closed-loop accurate blowing is realized.

The soot blower is arranged in the rotor heat transfer element, so that the soot blowing efficiency of the soot blower of the air preheater is improved, and the blowing-through property of the soot blower to the heat transfer element is ensured. Therefore, the blockage of the heat transfer element at the section easy to block can be directly washed and removed, the problem of blockage of the heat transfer element of the air preheater is effectively solved, and favorable conditions are provided for fully ensuring that the air preheater does not block and stop running during the running of the boiler. Under the condition of basically not changing the overall structure of the air preheater, the anti-blocking reliability of the air preheater is realized, and conditions are created for further improving the heat exchange efficiency of the air preheater and reducing the smoke exhaust temperature. The novel air preheater structure is small in investment and large in effect. The intelligent accurate purging control system adopted by the invention is beneficial to improving the anti-blocking efficiency of the air preheater and saving soot blowing media. The problem of short service life of the air preheater element caused by over-blowing is avoided, and the soot blowing efficiency of the counterweight blocking position is improved.

The invention can be fully suitable for the pulverized coal boiler with the SCR denitration system, can replace the traditional rotary air preheater, and solves the problem of frequent blockage of the heat transfer element after the denitration of the pulverized coal boiler. The invention can essentially solve the problem of frequent blockage of the air preheater, is an ideal prevention and treatment measure for preventing ABS condensation blockage, and can be popularized and applied in a large area.

Compared with the prior art, the invention has the following advantages:

(1) according to the invention, through an ingenious structure, the soot blower capable of swinging for blowing is added in the rotor heat transfer element of the air preheater, so that the blowing effect of a soot blowing system of the air preheater is greatly improved, the problem of blockage of the heat transfer element of the air preheater is effectively solved, and the air preheater is fully ensured not to be blocked and shut down during the operation of the boiler.

(2) An ultrasonic generator of a secrecy technology is additionally arranged on a high-temperature steam inlet pipeline of a soot blower of an air preheater, so that the soot blower has a blowing and blocking function during operation, and simultaneously utilizes the cavitation action of ultrasonic waves in a medium to achieve certain surface dirt peeling of a heat exchange element, so that steam soot blowing has a cleaning function, and finally, no dust is accumulated on the surface of the heat exchange element, and ABS crystals cannot be adhered to the surface of the heat exchange element.

(3) The blocking condition of the heat transfer element in each bin of the air preheater can be accurately monitored, and the fixed-point purging function of the through-flow section of the air preheater is realized during operation.

(4) The intelligent digital air preheater monitoring (adopting cross section multipoint arrangement) and control system can accurately control the distribution conditions of temperature, pressure and flow field to the bin area, can clearly monitor the analysis of the surface dust deposition and dust deposition trend of the heat exchange element according to a software algorithm, and accurately control the accurate position and the action duration of the blowing of the soot blower.

In conclusion, the rotary air preheater can be fully suitable for the pulverized coal fired boiler with the SCR denitration system, can replace the traditional rotary air preheater, and solves the problem that the heat transfer element is frequently blocked after the pulverized coal fired boiler is subjected to denitration.

Drawings

FIG. 1 is a schematic structural diagram of an anti-blocking rotary air preheater according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the positions of the sootblower air supply lines and control valve actuators provided by an embodiment of the present invention.

Fig. 3 is a schematic view of a soot blower provided by an embodiment of the present invention making a fan-shaped swing in a fan-shaped bin.

Fig. 4 is a schematic structural diagram of a swing directional valve provided in an embodiment of the present invention.

In the figure: 1. firstly, a soot blower; 2. a second soot blower; 3. a third soot blower; 4. a cold air inlet; 5. a rotary joint; 6. a flue gas outlet; 7. a cross-sectional flow field sensor; 8. a secondary heat transfer element; 9. ABS concentrates the blocked space; 10. a first stage heat transfer element; 11. a flue gas inlet; 12. an air preheater housing; 13. an air preheater rotating shaft; 14. a hot air outlet; 15. soot blowing lift valve opening and closing actuator; 16. soot blowing poppet valves; 17. an annular distribution header; 18. a sootblower gas source tube; 19. an upper bearing of the air preheater; 20. blowing a gun barrel; 21. a guide rail wheel; 22. a fan-shaped swing trajectory; 23. iron collision; 24. a valve core; 25. an incoming air flow port.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In view of the problems of the prior art, the present invention provides an anti-blocking type rotary air preheater, which is described in detail below with reference to the accompanying drawings.

As shown in figure 1, a certain space is left between the heat transfer elements at the cold and hot ends of the rotor of the traditional rotary air preheater, and a soot blower (a third soot blower 3 is shown in figure 1) is additionally arranged

As shown in fig. 1 and 2, an air preheater rotating shaft 13 is mounted on an air preheater shell 12 through an air preheater upper bearing 19, and a soot blowing poppet valve opening and closing actuator 15 is mounted on the left side of the air preheater upper bearing 19; the lower end of an upper bearing 19 of the air preheater is provided with a soot blowing lift valve 16 and an annular distribution header 17, the annular distribution header 17 is connected with a rotary joint 5 through a pipeline, and the rotary joint 5 is respectively connected with a first soot blower 1, a second soot blower 2 and a third soot blower 3 through a soot blower air source pipe 18.

As shown in FIG. 3, a soot blowing lift valve 16 is installed on the annular distribution header 17, the soot blowing lift valve 16 is connected with a soot blowing gun pipe 20, a guide rail wheel 21 is installed at the end part of the soot blowing gun pipe 20, and the track of the guide rail wheel 21 is a fan-shaped swinging track 22. The soot blowing gun arranged in each bin in the rotary air preheater rotor can perform approximate bin sector swing blowing in the rotor bin grids, so that the nearly full-coverage blowing of the through-flow section in the bin grids is realized.

As shown in fig. 4, a swing reversing valve is installed at the end of the third soot blower 3, an incoming air flow port 25 is arranged in the swing reversing valve, a stop 23 and a valve core 24 are installed in the swing reversing valve, and the stop 23 is connected with the valve core 24. The swinging of each soot blowing gun in the bin is provided with swinging power by the counterforce generated by spraying media from the adjustable nozzles at the ends of the gun rods. The power nozzle is alternatively opened by touching the reversing valve by the limit at two sides, so that the reciprocating swing of the soot blowing gun is realized.

The working principle of the invention is as follows: under the condition of ensuring that the original heat transfer efficiency of the original rotary air preheater (traditional) is not changed, the height positions of the heat transfer elements in the bins are rearranged, a layer of space is reserved in the rotor elements, and the soot blowers are additionally installed. A rod soot blower is additionally arranged in the space reserved in each partition bin. The number of the soot blowers is the same as that of the bins of the air preheater. The front end of the soot blowing gun in each bin lattice is provided with a vector spray head capable of changing the blowing direction, and the spray head can provide power for enabling the soot blowing gun to swing in a sector mode, so that the soot blowing gun can sweep in a full-coverage mode in a sector through-flow section. The soot blower arrangement position is in the ABS concentrated forming stage, and can be used for performing key purging on a blockage concentrated area between sections.

The soot blower gas (steam) source arranged above is introduced through the rotor central cylinder and then connected to the distribution header, and each soot blower gun is connected to the distribution header through a rotary joint and an angle valve. The opening of each angle valve is completed by the action of an actuator arranged outside the air preheater, and the actuator penetrates into the air preheater through a telescopic rod to trigger the corresponding angle valve, so that the angle valve is opened. Through the cooperation of the angular speed of the rotor of the air preheater and the action time of the actuator, any one angle valve can be opened, so that the accurate soot blowing action is realized. In order to realize accurate soot blowing of a soot blower and avoid the problems of over-blowing and under-blowing, an array type flow field sensor group is additionally arranged on an air preheater airflow channel and used for feeding back the uniform distribution of an airflow field passed by the air preheater so as to judge the blocking condition of an air preheater element, and the soot blower is controlled by a program according to the blocking condition, so that intelligent closed-loop accurate blowing is realized.

In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are only for convenience in describing and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the invention.

The above description is only for the purpose of illustrating the present invention and the appended claims are not to be construed as limiting the scope of the invention, which is intended to cover all modifications, equivalents and improvements that are within the spirit and scope of the invention as defined by the appended claims.

Claims

1. Have and wash function, intelligent control, middle anti-blocking type air preheater who installs soot blower additional, its characterized in that: the anti-blocking type rotary air preheater with the purging function and the intelligent monitoring control system and the soot blower additionally arranged in the rotor is additionally provided with the soot blower between the heat transfer elements at the cold and hot ends of the rotor of the rotary air preheater;

the number of soot blowers additionally arranged in the rotor is the same as that of the rotary air preheater sub-bins, and each bin is provided with a rod soot blowing gun; a soot blowing medium pipeline is used for connecting soot blowing medium into an annular distribution box from the inside of a rotor central cylinder through a rotary joint, and each soot blowing gun is connected with the distribution box through the rotary joint and an angle valve;

an array type flow field sensor group is additionally arranged at the medium flue gas outlet end of the air preheater rotor; an ultrasonic generator is additionally arranged at the inlet of the soot blower pipeline.

2. The anti-blocking rotary air preheater with the purging function, the intelligent monitoring and control system and the soot blower additionally installed in the rotor as claimed in claim 1, is characterized in that: and a soot blowing gun arranged in each bin in the rotor of the rotary air preheater performs approximate bin sector swing purging in the rotor bin grids.

3. The anti-blocking rotary air preheater with the purging function, the intelligent monitoring and control system and the soot blower additionally installed in the rotor as claimed in claim 2, is characterized in that: the swinging of each soot blowing gun in the bin is provided with swinging power by the counterforce generated by spraying media from an adjustable nozzle at the end part of the gun rod; the power nozzle is alternatively opened by touching the reversing valve by the limit at two sides, so that the reciprocating swing of the soot blowing gun is realized.

4. The anti-blocking rotary air preheater with the purging function, the intelligent monitoring and control system and the soot blower additionally installed in the rotor as claimed in claim 2, is characterized in that: the soot blowing gun is started by an actuator outside the air preheater, after the actuator moves, the telescopic rod extends into the air preheater to touch the angle valve of the corresponding soot blowing gun, so that the angle valve is opened, the position corresponding to each angle valve is programmed into a control system program according to the angular speed of the rotor of the air preheater, the accurate alignment control of each soot blowing gun is realized, and the soot blowing gun to be started is freely selected.

5. The anti-blocking rotary air preheater with the purging function, the intelligent monitoring and control system and the soot blower additionally installed in the rotor as claimed in claim 1, is characterized in that: an ultrasonic generator is additionally arranged on a high-temperature steam inlet pipeline of the soot blower of the air preheater, so that the steam soot blower has a cleaning function.

6. A rotary air preheater characterized by: the rotary air preheater is provided with the anti-blocking rotary air preheater with a purging function, an intelligent monitoring and controlling system and a soot blower additionally arranged in a rotor, wherein the soot blower is arranged in any one of claims 1 to 5.