CN213453608U - W flame boiler degree of depth peak shaving system based on flue gas recirculation - Google Patents
W flame boiler degree of depth peak shaving system based on flue gas recirculation Download PDFInfo
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- CN213453608U CN213453608U CN202022305827.7U CN202022305827U CN213453608U CN 213453608 U CN213453608 U CN 213453608U CN 202022305827 U CN202022305827 U CN 202022305827U CN 213453608 U CN213453608 U CN 213453608U
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Abstract
The utility model provides a W flame boiler degree of depth peak shaving system based on flue gas recirculation, the technique of the extremely low load steady operation ability of reinforcing W flame boiler strengthens the ability of surely firing of buggy torch under the extremely low load, improves boiler soda characteristic, makes W flame boiler possess degree of depth peak shaving ability. The system comprises a coal-fired boiler system and a furnace smoke system; the coal-fired boiler system comprises a hearth, a pulverized coal burner assembly, a secondary air nozzle assembly and a boiler fuel pulverizing system, wherein the pulverized coal burner assembly and the secondary air nozzle assembly are arranged on the hearth; the furnace smoke system comprises a furnace smoke conveying pipeline and a furnace smoke fan arranged on the furnace smoke conveying pipeline; the input end of the furnace smoke conveying pipeline is respectively connected with the hearth and different positions of a tail flue of the hearth and is used for pumping high-temperature smoke; the output end of the furnace smoke conveying pipeline is connected with the pulverized coal burner assembly and the secondary air nozzle assembly and used for circularly introducing high-temperature flue gas into the hearth.
Description
Technical Field
The utility model belongs to the technical field of coal-fired thermal power generating unit flexibility is reformed transform, relate to the flue gas recirculation technique, specifically be a W flame boiler degree of depth peak shaving system based on flue gas recirculation.
Background
The peak regulation device aims to solve the problems that a large coal-fired thermal power generating unit is difficult to regulate peaks and a heat supply unit abandons light and wind in the heating period in winter. The lowest oil-free stable combustion load of the existing thermal power generating unit which uses a small amount of high-volatile bituminous coal is reduced to be below 30% of rated load through local system transformation and refined operation adjustment.
The W flame boiler is a main boiler type burning low-volatile coal in China, the arrangement mode of a combustion system is dispersed, the operation state of a single combustor is relatively independent, and the lowest oil-throwing-free stable combustion load of a general W flame boiler can only reach about 50% of the rated output of the boiler. Under the existing technical conditions, the load of the boiler is further reduced, only an oil gun is put into the boiler to stabilize the combustion, and the deep peak regulation of the W flame boiler cannot be realized. In addition, W flame boiler furnace structure is special, and the big proportion of boiler flue gas volume reduces under extremely low load, and the soda parameter generally can't reach standard, influences steam turbine system operation safety.
SUMMERY OF THE UTILITY MODEL
To the problem that exists among the prior art, the utility model provides a W flame boiler degree of depth peak shaving system based on flue gas recirculation, the extremely low load steady operation ability of reinforcing W flame boiler strengthens the ability of surely firing of buggy torch under the extremely low load, improves boiler steam-water characteristic, makes W flame boiler possess degree of depth peak shaving ability.
The utility model discloses a realize through following technical scheme:
a W flame boiler deep peak regulation system based on flue gas recirculation comprises a coal-fired boiler system and a flue gas system;
the coal-fired boiler system comprises a hearth, a pulverized coal burner assembly, a secondary air nozzle assembly and a boiler fuel pulverizing system, wherein the pulverized coal burner assembly and the secondary air nozzle assembly are arranged on the hearth;
the furnace smoke system comprises a furnace smoke conveying pipeline and a furnace smoke fan arranged on the furnace smoke conveying pipeline; the input end of the furnace smoke conveying pipeline is respectively connected with the hearth and different positions of a tail flue of the hearth and is used for pumping high-temperature smoke; the output end of the furnace smoke conveying pipeline is connected with the pulverized coal burner assembly and the secondary air nozzle assembly and used for circularly introducing high-temperature flue gas into the hearth.
Preferably, the pulverized coal burner assembly comprises a dense phase nozzle assembly, a dead gas nozzle assembly and a dense-dilute separation device; the input end of the dense-dilute separation device is connected with the output end of the powder making system, and the output end of the dense-dilute separation device is respectively connected into the hearth through the dense-phase nozzle assembly and the exhaust nozzle assembly; the output end of the furnace smoke conveying pipeline is respectively connected to the front powder pipe at the input end of the thick-thin separation device and the thick-phase nozzle component at the output end of the furnace smoke conveying pipeline through a three-way control valve.
Further, an inlet of the exhaust gas nozzle assembly is provided with an exhaust gas air speed adjusting baffle plate for balancing flow speed distribution in the exhaust gas nozzle assembly and the dense-phase nozzle assembly.
Preferably, the secondary air nozzle assemblies are respectively arranged above and below the furnace arch of the hearth.
Preferably, the input end of the flue gas conveying pipeline is connected with the coal economizer outlet flue, the boiler steering chamber and the furnace bottom ash cooling hopper through the leading-out pipeline respectively and used for extracting high-temperature flue gas.
Furthermore, the extraction pipelines of the three extraction points are respectively provided with an adjusting baffle and a thermal measurement point.
Compared with the prior art, the utility model discloses following profitable technological effect has:
the utility model introduces the high temperature flue gas as the combustion product of the boiler into the hearth and the tail flue of the W flame boiler through the newly added boiler smoke system into the original pulverized coal burner and the secondary air nozzle component of the boiler for circulation and enters the hearth to participate in the combustion heat exchange process; the coal powder burner assembly reenters the W flame boiler combustion system, the stable combustion capacity of a low-load coal powder torch can be enhanced, meanwhile, the recirculated boiler smoke enters the hearth through the secondary air nozzle assembly, the steam-water characteristic of the boiler under extremely low load can be improved, and the W flame boiler has deep peak regulation capacity.
Furthermore, the high-temperature flue gas introduced into each component of the combustion system can be from different positions of a hearth and a tail flue, or can be obtained by mixing a plurality of strands of flue gas extracted from different positions and at different temperatures, and the temperature and the flow of the flue gas entering each component of the combustion system can be selected according to requirements.
Drawings
Fig. 1 is the utility model discloses a W flame boiler degree of depth peak shaver system's based on flue gas recirculation structural schematic.
In the figure: the system comprises a coal-fired boiler 100, a flue gas system 200, a hearth 1, a dense phase nozzle component 2, an exhaust nozzle component 3, a dense-dilute separation device 4, a secondary air nozzle component 5, a boiler fuel preparation system 6, a flue gas fan 7 and a flue gas conveying pipeline 8.
Detailed Description
The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.
The utility model relates to a W flame boiler degree of depth peak shaving system based on flue gas recirculation, pass through W flame boiler coal burner subassembly with the overgrate air spout subassembly with high temperature furnace smoke and introduce the furnace circulation, on the one hand through improving the stable fire of wind powder mixture temperature, on the other hand flue gas realizes recirculation via the overgrate air spout, improves the heat transfer effect that the low-load operating mode convection heating surface to promote the low-load operational capability that W flame boiler participated in the electric wire netting degree of depth peak shaving and improve the operation index during the low-load peak shaving greatly. For an actual boiler, the flow of the flue gas introduced into the pulverized coal burner component and the secondary air nozzle component is obtained by calculating a target air-pulverized coal temperature value and a designed nozzle air speed value, and the total high-temperature flue gas circulation volume and temperature are regulated and controlled in real time according to unit load and steam-water parameters.
As shown in fig. 1, the utility model relates to a W flame boiler degree of depth peak shaving system based on flue gas recirculation, including coal fired boiler system 100 and flue gas system 200.
The utility model provides a coal fired boiler system 100 includes furnace 1, pulverized coal burner subassembly, overgrate air spout subassembly 5 and boiler fuel's powder process system 6. The pulverized coal burner component comprises a dense phase nozzle component 2, a dead gas nozzle component 3 and a dense-dilute separation device 4; the coal pulverizing system 6 comprises a coal feeder, a coal mill and a separator which are sequentially connected.
The fume system 200 comprises a fume conveying duct 8 and a fume fan 7 arranged on the fume conveying duct 8.
The input end of the flue gas conveying pipeline 8 extracts high-temperature flue gas from different positions of a boiler hearth and a tail flue, and the output end of the flue gas conveying pipeline is introduced into a pulverized coal burner assembly and a secondary air nozzle assembly 5 of the coal-fired boiler system 100.
The high-temperature furnace smoke can be independently led out from the extraction point (i), the high-temperature furnace smoke can be independently led out from the extraction point (ii) or the high-temperature furnace smoke can be extracted from the extraction point (iii) or the high-temperature furnace smoke (iii) or can be extracted from the extraction point (iii) and mixed, then the high-temperature furnace smoke is conveyed to the pulverized coal burner component and the original secondary air nozzle component 5 through the furnace smoke conveying pipeline 8 after being pressurized by the furnace smoke blower 7, and the secondary.
The extraction points are respectively a coal economizer outlet flue, a boiler steering chamber and a furnace bottom cold ash hopper, the required circulating flue gas temperature is controlled by independently introducing one or a plurality of strands of flue gas with different temperatures and flows, and the flue gas circulating amount is determined according to the condition of coal quality entering the furnace. And the leading-out pipelines of the three extraction points are respectively provided with an adjusting baffle and a thermal measurement point.
The extracted flue gas directly winds the powder making system 6 after passing through the flue gas fan, the flue gas is respectively introduced into the pulverized coal burner assembly and the secondary air nozzle assembly according to a certain proportion, the heat of the high-temperature flue gas is supplied to pulverized coal airflow and secondary air, and the mixed circulating flue gas enters the hearth to participate in the combustion and heat exchange process.
The resistance characteristics of the rich-lean separation device 4 of the pulverized coal burner components in different forms are greatly different, if the system resistance of the rich-lean separation device 4 is within the allowable range of the working pressure of the flue gas blower 7, the high-temperature flue gas pressure from the flue gas blower 7 is enough to overcome the system resistance of the rich-lean separation device 4 and subsequent structures, and the high-temperature flue gas to the pulverized coal burner components can be introduced from a pulverized coal pipeline in front of the rich-lean separation device 4; the coal powder and the uniform coal powder airflow output by the powder making system 6 are mixed and heated, then enter a hearth, are heated by flame radiation and smoke convection in the furnace and are ignited and combusted in advance.
If the system resistance of the concentration separation device 4 is relatively higher and exceeds the working pressure of the furnace smoke fan 7, namely the pressure of high-temperature furnace smoke coming out of the furnace smoke fan 7 is insufficient, the high-temperature furnace smoke is introduced from the concentration nozzle component 2 behind the concentration separation device 4, mixed with the concentrated-phase coal powder airflow from the concentration separation device 4 and heated up, and then enters a hearth to be subjected to flame radiation and smoke convection heating in the furnace so as to catch fire and burn in advance.
After the high-temperature furnace smoke is introduced into each component of the pulverized coal burner, the high-temperature furnace smoke is mixed with the dense-phase pulverized coal airflow from the dense-thin separation device 4 or the uniform pulverized coal airflow in front of the dense-thin separation device 4, the temperature of the pulverized coal airflow is increased from 100-120 ℃ to about 200-300 ℃, and the oxygen concentration in the pulverized coal airflow is reduced. The temperature of the coal powder airflow rises by more than 100 ℃ and the oxygen concentration is reduced, the coal powder airflow is ignited in advance on the whole after the coal powder burner assembly introduces high-temperature furnace smoke, the stable combustion capability of the coal powder torch is enhanced, and the combustion stability of low-load operation of the boiler is improved.
In operation, the flow velocity distribution in the exhaust gas nozzle component 3 and the dense phase nozzle component 2 can be balanced through the exhaust gas air velocity adjusting baffle plate. The high-temperature flue gas entering the secondary air nozzle component 5 is mixed with secondary air and then enters a hearth, so that the mixing of the primary air and the secondary air is promoted, and oxygen required by the combustion of each stage of the pulverized coal is further supplemented. And then the flue gas generated by coal combustion and the recycled flue gas leave the outlet of the hearth together to exchange heat with the downstream heating surfaces at all stages.
After high-temperature furnace smoke enters a hearth through the secondary air nozzle assembly, the smoke flow through the convection heating surface is increased, the heat absorption capacity of the main convection heating surface is increased, the temperature of main and reheated steam is increased under low load, and the running economy and safety of a unit with extremely low load are improved.
And a flow and temperature measuring device is arranged on the flue gas conveying pipeline 8 to ensure the safe and stable operation of the system. Before the inlet of the furnace smoke blower 7 and the furnace smoke are introduced into each component of the combustion system, an electric adjusting door is arranged on each furnace smoke pipeline to control the proper smoke quantity to pass through.
After the high-temperature furnace smoke enters the hearth 1 through the dense-phase nozzle component 2 or the dense-dilute separation device 4 front powder pipe and the secondary air nozzle component 5, the temperature of the pulverized coal airflow is increased, the ignition of the pulverized coal airflow is advanced, and the stable combustion capability under low load is improved. Before and after the pulverized coal is ignited, air classification in the combustion process is more sufficient and ideal, meanwhile, the smoke as inert gas reduces the oxygen concentration in the pulverized coal airflow in the initial combustion stage, the excess air coefficient in the initial combustion stage is reduced, and the concentration of NOx generated by combustion is reduced due to the application of flue gas recirculation. After the flue gas recirculation is adopted, the total flue gas quantity at the outlet of the hearth is increased, the heat exchange quantity of the downstream convection heating surface is increased, and the temperatures of main steam and reheat steam under low load are increased.
The W flame boiler combustion system described in fig. 1 is used only as a system schematic, and actually the present invention proposes a W flame boiler based on different types, in which the arrangement of the dense phase nozzle assembly 2, the exhaust gas nozzle assembly 3, the dense-dilute separation device 4, and the secondary air nozzle assembly 5 is not limited to the position relationship described in the schematic diagram.
The utility model solves the problems of poor stable combustion performance, low steam-water parameter and difficult control of NOx in the deep peak regulation of the W flame boiler by utilizing the boiler smoke recycling technology, and improves the deep peak regulation capability of the W flame boiler; the W flame boiler is suitable for W flame boilers with the requirement of flexible modification. In the aspect of improving the deep peak regulation capacity of the W flame boiler, the corresponding system of the utility model has greatly reduced operation cost and does not need to supply extra fuel; the flue gas system has mature process equipment, and the operation safety risk is small; the smoke recycling technology is combined with the W flame boiler flexibility modification, so that the main operation contradiction existing when the W flame boiler participates in deep peak shaving is solved at one time; the original combustion system component can be locally transformed and continuously used, and the transformation workload is small.
When the utility model is used, according to the coal quality condition of the coal entering the furnace, the required circulating flue gas temperature and the required flue gas circulating amount are controlled by independently introducing one of the furnace smoke or a plurality of furnace smoke with different temperatures and flows; the extracted high-temperature furnace smoke directly bypasses the powder making system after passing through the furnace smoke fan 7, the high-temperature furnace smoke is respectively introduced into the pulverized coal burner assembly and the secondary air nozzle assembly according to a set proportion, the heat of the furnace smoke is supplied to pulverized coal airflow and secondary air, circulating flue gas enters the hearth to participate in the combustion and heat exchange processes, and deep peak regulation is carried out on the W flame boiler.
The system comprises a coal economizer, a boiler steering chamber, a furnace bottom ash cooling hopper, a gas inlet pipe, a gas outlet pipe, a gas inlet pipe, a gas outlet pipe.
If the system resistance of the concentration separation device 4 is within the allowable range of the working pressure of the smoke blower 7, high-temperature smoke to the pulverized coal burner component is introduced from a pulverized coal pipeline in front of the concentration separation device 4; the coal powder and the uniform coal powder airflow output by the powder making system 6 are mixed and heated, then enter a hearth, are heated by flame radiation and smoke convection in the furnace and are ignited and combusted in advance;
if the system resistance of the concentration separation device 4 exceeds the working pressure of the furnace smoke blower 7, high-temperature furnace smoke is introduced from the concentration nozzle component 2 behind the concentration separation device 4, mixed with the concentration coal powder airflow output by the concentration separation device 4, heated and enters a hearth, and is subjected to flame radiation and smoke convection heating in the furnace to further catch fire and burn in advance.
The high-temperature furnace smoke is mixed with the dense-phase coal dust airflow output by the dense-dilute separation device 4 or the uniform coal dust airflow in front of the dense-dilute separation device 4, and the temperature of the coal dust airflow is increased from 100-120 ℃ to 200-300 ℃.
Claims (6)
1. A W flame boiler deep peak shaving system based on flue gas recirculation is characterized by comprising a coal-fired boiler system (100) and a flue gas system (200);
the coal-fired boiler system (100) comprises a hearth (1), a pulverized coal burner assembly and a secondary air nozzle assembly (5) which are arranged on the hearth, and a boiler fuel pulverizing system (6) connected to the input end of the pulverized coal burner assembly;
the furnace smoke system (200) comprises a furnace smoke conveying pipeline (8) and a furnace smoke fan (7) arranged on the furnace smoke conveying pipeline (8); the input end of the furnace smoke conveying pipeline (8) is respectively connected with the hearth (1) and different positions of a tail flue of the hearth (1) and is used for pumping out high-temperature smoke; the output end of the furnace smoke conveying pipeline (8) is connected with the pulverized coal burner assembly and the secondary air nozzle assembly (5) and is used for circularly introducing high-temperature smoke into the hearth (1).
2. The W-flame boiler deep peaking system based on flue gas recirculation of claim 1, characterized in that, the pulverized coal burner assembly includes a dense phase nozzle assembly (2), a dead gas nozzle assembly (3) and a dense-dilute separation device (4); the input end of the dense-dilute separation device (4) is connected with the output end of the pulverizing system (6), and the output end of the dense-dilute separation device (4) is respectively connected into the hearth (1) through the dense-phase nozzle component (2) and the exhaust nozzle component (3); the output end of the furnace smoke conveying pipeline (8) is respectively connected to the front powder pipe at the input end of the thick-thin separation device (4) and the thick-phase spout component (2) at the output end through a three-way control valve.
3. The W-flame boiler depth peaking system based on flue gas recirculation of claim 2, characterized in that the inlet of the exhaust gas nozzle assembly (3) is provided with an exhaust gas wind speed adjusting baffle for balancing the flow velocity distribution in the exhaust gas nozzle assembly (3) and the dense phase nozzle assembly (2).
4. The W-flame boiler deep peaking system based on flue gas recirculation of claim 1, characterized in that the secondary air nozzle assemblies (5) are respectively arranged above and below the crown of the furnace (1).
5. The W-flame boiler depth peak-shaving system based on flue gas recirculation according to claim 1, characterized in that the input end of the flue gas conveying pipeline (8) is respectively connected with the exit flue of the coal economizer, the boiler steering chamber and the bottom cold ash hopper through the leading-out pipeline for extracting high-temperature flue gas.
6. The W-flame boiler depth peak regulation system based on flue gas recirculation according to claim 5, characterized in that the extraction pipes of the three extraction points are respectively provided with an adjusting baffle and a thermal measurement point.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023202634A1 (en) * | 2022-04-20 | 2023-10-26 | 西安热工研究院有限公司 | Flue gas circulation system for improving combustion characteristics and thermal characteristics of pulverized coal fired boiler |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023202634A1 (en) * | 2022-04-20 | 2023-10-26 | 西安热工研究院有限公司 | Flue gas circulation system for improving combustion characteristics and thermal characteristics of pulverized coal fired boiler |
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