CN111256106A - Metal wall temperature adjusting system for high-temperature heating surface - Google Patents
Metal wall temperature adjusting system for high-temperature heating surface Download PDFInfo
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- CN111256106A CN111256106A CN202010238284.3A CN202010238284A CN111256106A CN 111256106 A CN111256106 A CN 111256106A CN 202010238284 A CN202010238284 A CN 202010238284A CN 111256106 A CN111256106 A CN 111256106A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G5/00—Controlling superheat temperature
- F22G5/04—Controlling superheat temperature by regulating flue gas flow, e.g. by proportioning or diverting
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G5/00—Controlling superheat temperature
- F22G5/06—Controlling superheat temperature by recirculating flue gases
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Abstract
The invention discloses a metal wall temperature regulating system of a high-temperature heating surface, wherein an outlet of an induced draft fan is communicated with an inlet of a first valve, an outlet of a cold primary air duct of an air preheater is communicated with an inlet of a second valve, an outlet of the second valve and an outlet of the first valve are communicated with an inlet of a purging main pipe, inlets of first long telescopic propulsion devices and inlets of second long telescopic propulsion devices are communicated with an outlet of the purging main pipe, and the outlet of each first long telescopic propulsion device is communicated with a first purging nozzle, each first purging nozzle is positioned between the high-temperature superheater and the separating screen superheater, the outlet of each second long telescopic propulsion device is communicated with a second purging nozzle, each second purging nozzle is positioned between the final-stage reheater and the high-temperature superheater, the system can effectively solve the problem of overtemperature of the metal pipe wall of the heating surface, and has higher safety and economical efficiency.
Description
Technical Field
The invention belongs to the field of thermal power generation equipment, and relates to a metal wall temperature adjusting system for a high-temperature heating surface.
Background
Overtemperature pipe explosion of the metal pipe walls of the separating screen superheater, the high-temperature superheater and the final reheater of the thermal power generating unit is a ubiquitous problem, the safe and stable operation of the thermal power generating unit is threatened constantly, and the non-stop accident happens to the individual thermal power generating unit.
The reason for causing the overtemperature of the metal pipe wall of the high-temperature heating surface is more. Firstly, the metal grade of the heating surface is insufficient; secondly, the flow of working medium in individual tubes is small due to foreign matter blockage or oxide skin accumulation, and overtemperature tube explosion is formed. Thirdly, the influence of coal quality mainly comprises deviation of coal quality from a design value or low ash melting point, coking of a heating surface in the furnace, rise of flame center and over-temperature tube explosion caused by poor heat transfer. Fourthly, in the aspect of combustion control, the excessive deviation of the concentration of primary air and powder, the improper distribution of secondary air, the poor installation accuracy of a combustor and the like mainly exist, so that the excessive deviation of the flue gas temperature and the flow velocity of the high-temperature superheater and the final-stage reheater area is caused, and the overtemperature is further caused.
Aiming at the problem of over-temperature of the metal pipe wall of the heating surface, the problem can be generally considered from two aspects of a working medium side and a smoke side. In addition to upgrading of tube panel materials, the method mainly adopts the powder making and combustion optimization adjustment tests, and reduces the smoke temperature of the over-temperature heating surface and the tube wall temperature of the heating surface by optimizing the air distribution mode of the boiler, reducing the air-powder concentration deviation and other measures. Of course, in some cases, the over-temperature problem of the metal pipe wall caused by the design and installation quality of the burner, the residual rotation of the flue gas and the coking of the boiler furnace cannot be solved by adjusting the operation mode.
In addition, the temperature of the metal wall of the heating surface can be controlled below an alarm limit value by adding the desuperheating water and extremely adjusting the smoke baffle, but the economic performance of the unit operation can be reduced by adding a large amount of desuperheating water or frequently adjusting the smoke baffle. Example 1: the temperature of the pipe walls of No. 1 and No. 8 of a 58-screen reheater of a final-stage reheater of a boiler of a 660MW ultra-supercritical coal-fired unit always exceeds an alarm value (621 ℃), the temperature of the pipe walls can be controlled to be about 616 ℃ by closing a flue gas baffle of the reheater and intermittently putting accident desuperheating water, but the temperature of reheated steam is reduced to 589 ℃ (the design value is 603 ℃), so that the power supply coal consumption is increased by 0.83 g/kw.h; example 2: no. 120 tubes of a final reheater of a boiler of a certain 600MW supercritical coal-fired unit often exceed an alarm limit value (585 ℃), so that the accident desuperheating water is about 10t/h, and although the reheat steam temperature can reach a design value of 569 ℃, the accident desuperheating water causes the power supply coal consumption to rise by 1.03 g/kw.h.
It is emphasized that in the actual operation of some unit boilers, the problem that the overtemperature of the metal pipe wall of the heating surface cannot be controlled when the flue gas baffle is adjusted to the extreme position or the temperature-reducing water regulating door is fully opened is still solved. It is therefore desirable to design a system that addresses the above problems by optimizing the flue gas temperature field distribution in the area of the super heated surface, while providing both economy and safety.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a metal wall temperature adjusting system for a high-temperature heating surface, which can effectively solve the problem of overtemperature of the metal wall of the heating surface and has higher safety and economical efficiency.
In order to achieve the aim, the metal wall temperature adjusting system for the high-temperature heating surface comprises an induced draft fan, a first valve, a primary air fan, an air preheater, a second valve, a blowing main pipe, a plurality of first long telescopic propulsion devices and a plurality of second long telescopic propulsion devices;
an outlet of the induced draft fan is communicated with an inlet of a first valve and an inlet of an external desulfurization tower, an outlet of a primary fan is communicated with an inlet of a cold primary air duct of an air preheater, an outlet of the cold primary air duct of the air preheater is communicated with an inlet of a second valve, an outlet of the second valve is communicated with an inlet of a purging main pipe after being communicated with an outlet of the first valve through a pipeline, an inlet of each first long telescopic propulsion device and an inlet of each second long telescopic propulsion device are communicated with an outlet of the purging main pipe, an outlet of each first long telescopic propulsion device penetrates through the side wall of a boiler furnace to be inserted into the boiler furnace, an outlet of each first long telescopic propulsion device is communicated with a first purging nozzle, each first purging nozzle is positioned between a high-temperature superheater and a separating screen superheater, and an outlet of each second long telescopic propulsion device penetrates through the side wall of the flue to be inserted into the flue, and the outlet of each second long telescopic propulsion device is communicated with a second purging nozzle, and each second purging nozzle is positioned between the final-stage reheater and the high-temperature superheater.
The first long telescopic propulsion device is communicated with the purging main pipe through a third valve, the second long telescopic propulsion device is communicated with the purging main pipe through a fourth valve, and an outlet of the second valve is communicated with an outlet of the first valve through a pipeline and a pipe and then communicated with an inlet of the purging main pipe through a fifth valve.
The first blowing nozzle and the second blowing nozzle are both 360-degree blowing nozzles.
The purging main pipe is provided with a pressure gauge, a thermometer and a flowmeter.
The valve also comprises a check valve, wherein the outlet of the first valve is communicated with the inlet of the check valve, and the outlet of the check valve and the outlet of the second valve are communicated through a pipeline.
The number of the first long telescopic propulsion devices and the number of the second long telescopic propulsion devices are both two.
The invention has the following beneficial effects:
when the metal wall temperature adjusting system for the high-temperature heating surface is specifically operated, part of low-temperature flue gas output by the induced draft fan and part of hot primary air preheated by the air preheater are mixed in the blowing main pipe and then are sprayed into corresponding over-temperature areas of the final reheater and the high-temperature superheater through the first blowing nozzle and the second blowing nozzle so as to reduce the temperature of local flue gas and further control the temperature of metal on the wall of the pipe.
Furthermore, the pressure, the temperature and the flow of the blowing mixed air flow are regulated and controlled by adjusting the working states of the first valve, the second valve, the third valve, the fourth valve, the fifth valve, the induced draft fan and the primary air fan.
Furthermore, the invention is also provided with a check valve, so that hot primary air can be effectively prevented from reversely flowing into an outlet flue of the induced draft fan.
Drawings
FIG. 1 is a schematic flow diagram of the present invention;
fig. 2 is a distribution diagram of the first long telescopic propulsion device 81, the first purge nozzle 91, the second long telescopic propulsion device 82 and the second purge nozzle 92 according to the present invention.
Wherein, 1 is an induced draft fan, 2 is a primary air fan, 3 is an air preheater, 4 is a final reheater, 5 is a high temperature superheater, 6 is a separating screen superheater, 7 is a boiler furnace, 81 is a first long telescopic propulsion device, 82 is a second long telescopic propulsion device, 91 is a first purging nozzle, and 92 is a second purging nozzle.
Detailed Description
The invention is described in further detail below with reference to the accompanying drawings:
referring to fig. 1 and 2, the metal wall temperature adjusting system for a high-temperature heating surface according to the present invention includes an induced draft fan 1, a first valve, a primary air fan 2, an air preheater 3, a second valve, a purging main pipe, a plurality of first long telescopic propulsion devices 81 and a plurality of second long telescopic propulsion devices 82; an outlet of an induced draft fan 1 is communicated with an inlet of a first valve and an inlet of an external desulfurization tower, an outlet of a primary fan 2 is communicated with an inlet of a cold primary air duct of an air preheater 3, an outlet of the cold primary air duct of the air preheater 3 is communicated with an inlet of a second valve, an outlet of the second valve and an outlet of the first valve are communicated with an inlet of a purging main pipe through a pipeline and a pipe, an inlet of each first long telescopic propulsion device 81 and an inlet of each second long telescopic propulsion device 82 are communicated with an outlet of the purging main pipe, an outlet of each first long telescopic propulsion device 81 penetrates through the side wall of a boiler furnace 7 to be inserted into the boiler furnace 7, an outlet of each first long telescopic propulsion device 81 is communicated with a first purging nozzle 91, each first purging nozzle 91 is positioned between a high-temperature superheater 5 and a separating screen superheater 6, an outlet of each second long telescopic propulsion device 82 penetrates through the side wall of a flue to be inserted into the flue, and the outlet of each second long telescopic propulsion device 82 is communicated with a second purging nozzle 92, and each second purging nozzle 92 is positioned between the final stage reheater 4 and the high temperature superheater 5.
The first long telescopic propulsion device 81 is communicated with the purging main pipe through a third valve, the second long telescopic propulsion device 82 is communicated with the purging main pipe through a fourth valve, and an outlet of the second valve is communicated with an outlet of the first valve through a fifth valve after being connected with a pipeline; the invention also comprises a check valve, wherein the outlet of the first valve is communicated with the inlet of the check valve, and the outlet of the check valve and the outlet of the second valve are connected through a pipeline.
The first purge nozzle 91 and the second purge nozzle 92 are both 360 ° purge nozzles; the purging main pipe is provided with a pressure gauge, a thermometer and a flowmeter, and the number of the first long telescopic propulsion devices 81 and the number of the second long telescopic propulsion devices 82 are two.
The specific working process of the invention is as follows:
the flue gas of draught fan 1 output is divided into two routes, wherein enter into the desulfurizing tower and carry out deep desulfurization treatment all the way, another route enters into and sweeps the female pipe through first valve, check valve, the cold wind of primary air fan 2 output is divided into two routes after the cold wind channel of air heater 3 preheats, wherein enter into the coal pulverizer of powder process system all the way, another route enters into and sweeps the female pipe, the mixed gas stream that sweeps the female pipe output is divided into two routes, wherein enter into each first long telescopic advancing device 81 through the third valve all the way, then spout through first blowing nozzle 91, another route enters into each second long telescopic advancing device 82 through the fourth valve, then spout through second blowing nozzle 92.
The method comprises the steps of respectively detecting air pressure, air temperature and air flow in a purging main pipe through a pressure gauge, a thermometer and a flowmeter, adjusting the opening degree of a first valve, the opening degree of a second valve, the opening degree of a fifth valve, the power of a draught fan 1 and the power of a primary fan 2 to enable the pressure of mixed gas in the purging main pipe to be 1.0-10.0 kPa, the temperature to be 120-330 ℃, the flow to be 5-50 t/h, and the O content of flue gas2The mass percentage concentration is 4-21%, in practical application, the doping amount and pressure of the hot primary air and the low-temperature flue gas can be adjusted by adopting a first valve and a second valve according to the overtemperature condition of the metal pipe wall, and the blowing amount and pressure of the hot primary air and the low-temperature flue gas can be adjusted by adopting a fifth valveThe total flow of mixed gas is swept, the third valve and the fourth valve are adopted to respectively control the flow of sweeping gas in the areas of the final reheater 4 and the high-temperature superheater 5, the first sweeping nozzle 91 and the second sweeping nozzle 92 inject low-temperature sweeping gas into the metal pipe wall overtemperature area to reduce the temperature of flue gas in the area, the heat load distribution of the heating surface areas of the final reheater 4 and the high-temperature superheater 5 is homogenized, the steam temperature deviation and pipe wall overtemperature caused by residual rotation or vortex of the flue gas are weakened, the temperature of the metal pipe wall is controlled below an alarm value under the condition that the temperature of superheated steam and the temperature of reheated steam are close to the design values, the input of desuperheating water can be reduced to a great extent, and the power supply coal consumption can be reduced by about 0.7g/kw. In addition, after the system is put into use, the cleanliness conditions of the heating surfaces of the final-stage reheater 4 and the high-temperature superheater 5 can be seen, the input frequency of a steam soot blowing system is reduced, and the running economy and safety of a unit are improved.
In addition, it cannot be denied that the pressure of the blowing main pipe and the pressure of the outlet of the blowing nozzle are both smaller than the steam soot blowing pressure, and the steam soot blowing system is completely taken and is unrealistic, but the invention also has a certain cleaning effect on the floating soot attached to the heating surface of the high-temperature heating surface, and the steam soot blowing frequency can be reduced as appropriate according to the temperature of main steam, the temperature of reheated steam and the cleanliness of the heating surface in practical application, so that the running economy of the unit is improved.
Claims (6)
1. A metal wall temperature adjusting system for a high-temperature heating surface is characterized by comprising a draught fan (1), a first valve, a primary air fan (2), an air preheater (3), a second valve, a purging main pipe, a plurality of first long telescopic propulsion devices (81) and a plurality of second long telescopic propulsion devices (82);
an outlet of an induced draft fan (1) is communicated with an inlet of a first valve and an inlet of an external desulfurization tower, an outlet of a primary fan (2) is communicated with a cold primary air duct inlet of an air preheater (3), a cold primary air duct outlet of the air preheater (3) is communicated with an inlet of a second valve, an outlet of the second valve and an outlet of the first valve are communicated with an inlet of a purging main pipe after being communicated with each other through a pipeline, an inlet of each first long telescopic propulsion device (81) and an inlet of each second long telescopic propulsion device (82) are communicated with an outlet of the purging main pipe, an outlet of each first long telescopic propulsion device (81) penetrates through the side wall of a boiler hearth (7) and is inserted into the boiler hearth (7), an outlet of each first long telescopic propulsion device (81) is communicated with a first purging nozzle (91), and each first purging nozzle (91) is positioned between a high-temperature superheater (5) and a separating screen superheater (6), the outlet of each second long telescopic propulsion device (82) penetrates through the side wall of the flue to be inserted into the flue, the outlet of each second long telescopic propulsion device (82) is communicated with a second purging nozzle (92), and each second purging nozzle (92) is located between the final-stage reheater (4) and the high-temperature superheater (5).
2. The system for regulating the temperature of the metal wall on the high-temperature heating surface according to claim 1, wherein the first long telescopic propulsion device (81) is communicated with the purging main pipe through a third valve, the second long telescopic propulsion device (82) is communicated with the purging main pipe through a fourth valve, and an outlet of the second valve is communicated with an outlet of the first valve through a pipeline and then communicated with an inlet of the purging main pipe through a fifth valve.
3. The system for regulating the temperature of a metal wall on a high temperature heating surface according to claim 1, wherein the first purge nozzle (91) and the second purge nozzle (92) are both 360 ° purge nozzles.
4. The system for regulating the temperature of the metal wall on the high-temperature heating surface according to claim 1, wherein a pressure gauge, a temperature gauge and a flow meter are arranged on each purging main pipe.
5. The system of claim 1, further comprising a check valve, wherein an outlet of the first valve is connected to an inlet of the check valve, and an outlet of the check valve is connected to an outlet of the second valve through a pipe.
6. A high temperature hot surface metal wall temperature adjustment system according to claim 1, characterized in that the number of the first long telescopic propulsion devices (81) and the number of the second long telescopic propulsion devices (82) are both two.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010238284.3A CN111256106A (en) | 2020-03-30 | 2020-03-30 | Metal wall temperature adjusting system for high-temperature heating surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010238284.3A CN111256106A (en) | 2020-03-30 | 2020-03-30 | Metal wall temperature adjusting system for high-temperature heating surface |
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| Publication Number | Publication Date |
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| CN111256106A true CN111256106A (en) | 2020-06-09 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202010238284.3A Pending CN111256106A (en) | 2020-03-30 | 2020-03-30 | Metal wall temperature adjusting system for high-temperature heating surface |
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| CN (1) | CN111256106A (en) |
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2020
- 2020-03-30 CN CN202010238284.3A patent/CN111256106A/en active Pending
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