WO2015103831A1

WO2015103831A1 - Fuel/gas-saving ignition and stable-combustion low-nitrogen swirling pulverized coal combustor

Info

Publication number: WO2015103831A1
Application number: PCT/CN2014/077206
Authority: WO
Inventors: 高克迎; 程怀志
Original assignee: 徐州燃控科技股份有限公司
Priority date: 2014-01-13
Filing date: 2014-05-12
Publication date: 2015-07-16
Also published as: CN103759258A; CN103759258B

Abstract

A fuel/gas-saving ignition stable-combustion low-nitrogen swirling pulverized coal combustor, comprising a primary air channel (2), a multi-channel secondary air intake pipe and a fuel/gas combustor (1). A circle of straightening vanes (15) are evenly distributed on the inner wall of an entryway of a strengthened combustion chamber (16) in the primary air channel (2). A circle of swirling vanes (14) are evenly distributed on the front outer wall of the fuel/gas combustor (1). The length from the front end of the swirling vane (14) to the front end of the fuel/gas combustor (1) is larger than or equal to the length of the straightening vane (15), and the outer diameter of the swirling vane (14) is smaller than the inner diameter of the straightening vane (15). The fuel/gas combustor (1) is adjustable front and back, causing relative positions of the swirling vanes (14) and the straightening vanes (15) to change. The swirling intensity of secondary air of the combustor can be adjusted online, a proper high-temperature flue gas recirculation zone is formed in the center of a nozzle of the combustor through adjustment of the swirling intensity of the secondary air, and a stable heat source is provided for ignition and stable combustion of pulverized coal.

Description

Fuel-saving/gas ignition stable combustion low-nitrogen swirl pulverized coal burner

Technical field

The invention relates to a pulverized coal burner, in particular to a fuel-saving/gas ignition stable combustion low-nitrogen swirl pulverized coal burner suitable for a power station boiler.

Background technique

At present, power pulverized coal boilers in the world generally use large oil guns to achieve start-up and low-load steady combustion. According to statistics, the domestic power system is used for boiler commissioning, start-up, low-load stable combustion and shutdown combustion-supporting oil up to nearly 10 million tons per year, accounting for 15% of the country's total fuel consumption, worth tens of billions of yuan, and consumed a lot. The fuel resources also greatly increase the cost of power generation. China's coal resources are much richer than oil and gas resources. The coal-based energy consumption structure will not change in recent decades. The power generation industry is an industry with a large fuel consumption. It is a general trend to reduce fuel consumption and reduce power generation costs. The fuel-saving ignition technology based on coal instead of oil has developed rapidly in China in recent years and achieved good application results.

In recent years, with the emphasis on environmental protection, reducing nitrogen oxide emissions has become a key technology in keeping with fuel economy. However, many low-nitrogen burners currently have problems of severe wear, nozzle slagging and high-temperature corrosion, and are not adaptable to coal types.

At present, in the case of a swirl burner for a wall-fired boiler, the application of the fuel-saving ignition technique is to replace the primary air portion of a row of swirl burners with a fuel-efficient ignition pulverized coal burner, and the fuel-saving ignition pulverized coal. The burner does not have the performance structure of the low-nitrogen burner during normal operation of the boiler, which tends to reduce the low nitrogen and stable combustion performance of the entire row of swirl burners used for fuel-saving ignition technology.

Summary of the invention

Technical Problem: The object of the present invention is to provide a fuel-saving/gas ignition stable combustion low-nitrogen swirl pulverized coal burner with simple structure, strong adaptability of coal type, and low nitrogen oxide emission. .

Technical Solution: The fuel-saving/gas ignition stable combustion low-nitrogen pulverized coal pulverized coal burner of the invention comprises a primary air passage, a multi-channel secondary air inlet pipe, and an oil/gas burner extending into the primary air passage, once The outlet end of the air passage and the multi-channel secondary air inlet duct are all expanded structures, and the inner wall of the enhanced combustion chamber inlet passage in the primary air passage is uniformly provided with a plurality of rectifying blades arranged at a horizontal angle, the oil The outer wall of the front part of the gas burner is uniformly arranged with a swirling vane arranged at an oblique angle. The front end of the swirl vane is longer than or equal to the length of the rectifying vane, and the outer diameter of the swirling vane is smaller than The inner diameter of the rectifying blade; the multi-channel secondary air inlet pipe comprises a DC secondary air inlet pipe disposed on the outer circumference of the primary air passage, and the inner circumference of the direct current secondary air inlet pipe is provided with an internal swirling flow a secondary air inlet pipe in the swirling flow of the blade, and a swirling outer secondary air inlet pipe with an outer swirling blade inside the outer circumference of the secondary air inlet pipe in the swirling flow; the DC secondary air inlet pipe There is a front and rear movement regulating damper at the entrance. DC throttle adjustment lever, said spin The swirling damper adjusting rod of the front and rear movement regulating damper two air flow is provided at the inlet of the secondary air inlet pipe; the inner swirling vane is provided with an axial angle inner swirling vane adjusting rod, and the outer swirling vane An external angle swirling vane adjustment rod is provided.

The outer wall of the primary air passage is provided with a guide sleeve that allows the oil/gas burner to move back and forth into the primary air passage. Advantageous Effects: The burner of the invention has the characteristics of high efficiency and low nitrogen oxide emission, and solves the problems of serious wear of many low-nitrogen burners at present, nozzle slagging and high-temperature corrosion, and the internal and external secondary air can be adjusted by adjusting the rod. The air volume and / or swirl intensity, control the mixing time of the high temperature flue gas recirculation zone and the secondary air in the center of the burner nozzle, can adapt to the ignition and stable combustion requirements of different coal types. By setting a position-adjustable enhanced combustion fuel/gas burner in the primary air passage, by adjusting the position of the burner, the fuel-saving/air-ignition stabilized low-nitrogen swirl pulverized coal burner combines fuel economy and gas Low nitrogen characteristics. The swirling intensity can be adjusted online. By adjusting the swirling intensity of the secondary air, the burner forms a reasonable high-temperature flue gas recirculation zone at the center of the nozzle, providing a stable heat source for pulverized coal ignition and stable combustion. The burner 1 and the secondary air are all provided with a certain angle of the nozzle expansion structure, which can effectively control the timely mixing of the secondary air and the coal powder, and at the same time, the water wall area of the nozzle is in an oxidizing atmosphere, effectively preventing the water wall of the burner area. Slag formation and high temperature corrosion occur. The invention has good ignition stability, strong coal quality adaptability and low nitrogen oxide emission. The utility model has the advantages of simple structure, strong adaptability of coal type and good use effect, and has wide practicality in the technical field.

DRAWINGS

Figure 1 is a schematic view showing the structure of a burner of the present invention. 2 is a schematic view showing the position structure of the working process of the burner of the present invention. In the figure: 1 oil/gas burner, 2 primary air passage, 3 internal swirl vane adjustment rod, 4 external swirl vane adjustment rod, 5-swirl damper adjustment rod, 6-DC damper adjustment rod, 7-翼门一, 8—Secondary air inlet pipe, 9一风门二, 10 Circulating secondary air inlet pipe, 11 internal swirling blade, 12 swirling outer secondary air inlet pipe, 13 external swirling blade, 14一Swirl blades, 15 - rectifying blades, 16 fortified combustion chambers, 17 for expanding the vertebrae. detailed description

An embodiment of the present invention will be further described below with reference to the accompanying drawings: The fuel-saving/gas ignition stable combustion low-nitrogen swirl pulverized coal burner of the present invention mainly comprises an oil/gas burner 1, a primary air passage 2, a damper, The adjusting rod, the secondary air inlet pipe 8, the secondary air inlet pipe 10 in the swirling flow, the outer air inlet pipe 12 and the swirling vane are formed. The oil/gas burner 1 extends into the primary air passage 2, and the outer wall of the horizontal pipe section of the primary air passage 2 is provided with a guide sleeve for moving the oil/gas burner 1 into the primary air passage 2, and oil/ The axial line of the gas burner 1 The axial line of the horizontal pipe section of the primary air passage 2 coincides. The outlet end of the primary air passage 2, the secondary air inlet duct 8, the secondary air inlet duct 10 in the swirling flow, and the secondary air inlet duct 12 in the swirling flow are all dilated vertebrae structures, and the dilatation angles are all 30°. The inner wall of the inlet passage of the reinforced combustion chamber 16 in the primary air passage 2 is evenly distributed with a plurality of rectifying blades 15 arranged at a horizontal angle, and the front outer wall of the oil/gas burner 1 is uniformly distributed with a circle at an oblique angle. Arranging the swirling vanes 14, the front end of the swirling vanes 14 is greater than or equal to the length of the front end of the oil/gas burner 1 and the outer diameter of the swirling vane 14 is smaller than the inner diameter of the rectifying vane 15; The cooperation between the gas burner 1 and the inlet of the primary air passage 2 is a dynamic fit that can move back and forth to adjust the relative position between the swirling vane 14 and the rectifying vane 15, and the oil/gas burner 2 moves forward and backward by a distance greater than that of the rectifying vane 15 length. The multi-channel secondary air inlet pipe comprises a DC secondary air inlet pipe 8 disposed on an outer circumference of the primary air passage 2, and an inner swirling blade 11 is disposed on an outer circumference of the direct current secondary air inlet pipe 8. The swirling inner secondary air inlet pipe 10, the outer circumference of the secondary air inlet pipe 10 in the swirling flow is provided with a swirling outer secondary air inlet pipe 12 with an outer swirling vane 13 therein; The inlet of the air inlet pipe 8 is provided with a DC damper adjusting lever 6 for adjusting the damper of the front and rear movements, and a swirling damper for adjusting the damper of the front and rear movement regulating damper is provided at the entrance of the secondary air inlet pipe 10 in the swirling flow. The inner swirling vane 11 is provided with an axial angle inner swirling vane adjusting rod 3, and the outer swirling vane 13 is provided with an axial angle outer swirling vane adjusting rod 4.

Working principle: oil/gas ignition stable combustion The low-nitrogen swirling pulverized coal burner oil/gas burner 1 is installed in the primary air passage 2, and the inner and outer secondary air in the swirling flow are all adjustable with axial angle. The form is adjusted by the inner swirling blade adjusting rod 3 and the outer swirling blade adjusting rod 4, respectively, and the ratio of the inner and outer secondary air volume of the swirling flow is adjusted by the swirling damper adjusting rod 5 to move the damper 2 and 9 forward and backward. The secondary air in the direct current through the DC damper adjusting rod 6 drives the damper 7 to adjust the air volume before and after; adjusting the front and rear position of the oil/gas burner 1 to drive the displacement of the swirling vane 14 to drive the swirling vane 14 and the rectifying vane 15 Relative position changes.

When the boiler is started coldly, the burner is in the position shown in Fig. 1, and the oil/gas burner 1 is in the commissioning state. After the primary air powder enters the primary air passage 2, the rotary motion is first generated by the swirling vane 14, from the swirling vane 14 After coming out, the rectifying blades 15 are introduced, and under the rectifying action of the rectifying blades 15, a plurality of dense phase pulverized coal gas streams having the same number as the rectifying blades 15 are formed on the windward surface of the rectifying blades 15, and a plurality of light rays are formed on the back surface of the rectifying blades 15. Phase coal powder flow. The dense phase pulverized coal gas stream and the light phase pulverized coal gas stream enter the enhanced combustion chamber 16, and are ignited by the flame of the oil/gas burner 2 in the enhanced combustion chamber 16, and then ejected from the burner. At this time, the damper 7 is driven by the DC damper adjusting lever 6, so that the direct current air volume is large, and the wall surface of the combustion chamber is cooled and cooled to protect it from over-temperature and safe operation. Since the pulverized coal is densely phased and has a light phase interval distribution, a good environment is formed which is favorable for reducing NOx production, and the generation of NOx can be greatly reduced. The enhanced combustion chamber 16 is a very narrow space environment relative to the boiler furnace, so that the interior of the enhanced combustion chamber 16 can be reinforced with a small amount of oil/gas flame. Warming up to above the ignition temperature of the pulverized coal, to achieve the fuel-saving/gas purpose of igniting the pulverized coal with a small amount of oil/gas, thereby replacing the heating of the boiler with the heat of the pulverized coal by using the heat of the pulverized coal flame/gas. Above the ignition temperature, the pulverized coal of other pulverized coal burners is put into operation to complete the startup process of the boiler.

After the boiler start-up process is completed, the oil/gas burner 1 is in a stopped state, and the oil/gas burner 1 is moved forward to the enhanced combustion chamber 16, as shown in Fig. 2, after the primary air powder enters the primary air passage 2, first After the rectifying blade 15, a relatively uniform pulverized coal gas flow is generated, and the wind from the rectifying blade 15 enters the swirling vane 14 to generate a rotary motion, and the pulverized coal forms a distribution of the outer rich and the inner light under the action of the centrifugal force. The combination with the secondary air can reduce the formation of NOx. Adjusting the DC damper adjusting rod 6 to drive the damper 7 movement, so that the secondary air in the DC is reduced; adjusting the swirling damper adjusting rod 5 to drive the damper 2 to move, so that the proportion of the secondary air in the swirl is reduced, and the swirling is twice The proportion of wind is increased; the inner swirling vane adjusting rod 3 and the outer swirling vane adjusting rod 4 make the swirling intensity of the secondary air in the swirling flow and the secondary air in the swirling flow smaller. This weakens the mixing of the secondary air and the pulverized coal flame, delays combustion, and reduces NOx formation. The opposite adjustment method can improve the swirling intensity of the entire airflow, strengthen the mixing of pulverized coal and air, strengthen the pre-combustion, reduce the fly ash combustibles, and improve the combustion efficiency. By adjusting the adjustment rod to reduce or increase the intensity of the wind, the best ideal point for balancing NOx and fly ash combustibles can be found.

1. The secondary air duct spouts are all structures of the expanding vertebrae 7. The expansion angle of the expanding vertebra 7 is 30°. The mixing of the secondary air is delayed by the external expansion structure, so that the flow of the wind-blown powder is formed in the burner nozzle area. The field structure reaches an oxygen-deficient atmosphere inside the primary air at the beginning of the fire, so that the initial nitrogen oxides are fully reduced, and the wind wall formed by the externally expanded structure achieves the purpose of isolating the pulverized coal particles and the nozzle wall of the nozzle water wall region, thereby Effectively alleviate the chance of water wall coking and high temperature corrosion in the burner area.

Claims

Claim

1. An oil-saving/gas ignition stable combustion low-nitrogen pulverized coal pulverized coal burner, comprising a primary air passage (2), a multi-channel secondary air inlet duct, and an oil/gas combustion extending into the primary air passage (2) (1), the primary air passage (2), the outlet end of the multi-channel secondary air inlet duct is a dilatation structure, characterized in that: the intensified combustion chamber (16) inlet in the primary air passage (2) The inner wall of the channel is uniformly distributed with a plurality of rectifying blades (15) arranged at a horizontal angle, and the front outer wall of the oil/gas burner (1) is uniformly distributed with a swirling vane (14) arranged at an oblique angle. The front end of the flow vane (14) is greater than or equal to the length of the front end of the oil/gas burner (1), and the outer diameter of the swirl vane (14) is smaller than the inner diameter of the rectifying vane (15); The multi-channel secondary air inlet pipe comprises a DC secondary air inlet pipe (8) disposed on the outer circumference of the primary air passage (2), and the inner circumference of the DC secondary air inlet pipe (8) is internally provided The swirling vane (11) has a swirling inner secondary air inlet pipe (10), and the outer circumference of the swirling inner secondary air inlet pipe (10) is provided with an outer swirling vane (1) 3) a swirling outer secondary air inlet pipe (12); a DC damper adjusting rod (6) having a front and rear motion regulating damper (7) air volume at the inlet of the direct current secondary air inlet pipe (8), a swirling damper adjusting rod (5) having a front and rear motion regulating damper (9) air flow at the inlet of the secondary air inlet pipe (10) in the swirl; the inner swirling vane (11) is provided with an axial direction The angle can be an inner swirling vane adjusting rod (3), and the outer swirling vane (13) is provided with an axial angle outer swirling vane adjusting rod (4).

2 . The fuel-saving/gas ignition stable combustion low-nitrogen pulverized coal pulverized coal burner according to claim 1 , wherein: the outer wall of the primary air passage ( 2 ) is provided with oil/gas combustion The device (1) enters the guide sleeve that moves back and forth in the primary air passage (2).