A local oxygen-enriched precise combustion-supporting method and device for biomass boilers

Abstract

The present application relates to the field related to biomass furnaces, and discloses a local oxygen-enriched precise combustion-supporting method and device for biomass boilers. In order to solve the problem of difficult-to-control combustion in biomass boilers, the present application designs the best way to select high-temperature gas and oxygen-enriched mixture according to the characteristics of biomass grate furnaces, ensuring the formation of an optimal oxygen concentration gradient in the combustion area, promoting the full combustion and efficient utilization of biomass fuels, not only obtaining high-quality oxygen enrichment, but also eliminating the need to shut down the furnace during installation and maintenance. Therefore, the application has the advantages of easy installation, easier operation and maintenance, and greatly reducing production costs and operating costs.

Description

Technical Field

[0001] The present application relates to the field related to biomass furnaces, and in particular to a local oxygen-enriched precise combustion-supporting method and device for a biomass boiler. Background Art

[0002] Biomass energy is the fourth largest energy source after coal, oil and natural gas. It is a renewable and recyclable clean energy. It will become one of the most important energy sources in the world in the future. Biomass mainly includes the following aspects:

[0003] (1) Residues from the wood processing industry, such as bark, sawdust, etc.;

[0004] (2) Agricultural residues, such as rice husks, wheat straw, cotton stalks, etc.;

[0005] (3) Waste generated by human life, such as municipal garbage, sewage sludge, etc.;

[0006] (4) Special woody, herbaceous and aquatic plants used for biomass energy resource utilization.

[0007] Biomass fuel has the characteristics of high volatile content, large moisture change, loose volume, low energy density, high content of alkali metals such as potassium and sodium, low ash melting point, easy slagging, etc. Biomass is processed into granular or block biomass fuel through crushing, mixing, drying and extrusion to supply boiler combustion. Due to its wide distribution of sources, large quantity, low combustion pollution and advanced processing technology, biomass fuel has become an emerging green energy.

[0008] Types of biomass boilers include biomass steam boilers, biomass hot water boilers, biomass hot air furnaces, biomass thermal oil furnaces, vertical biomass boilers and horizontal biomass boilers. With the development of technology, biomass circulating fluidized bed boilers are also gradually gaining attention. Most of the common biomass layer-fired boilers are mainly SZ, SH and DH (corner tubes). The primary air is blown out from the bottom of the grate. Since biomass fuel mainly burns volatiles and the combustion time is shorter than that of mineral fuels such as coal, the upper and middle parts of the flame require more oxygen, and the primary air blown out from the bottom of the grate is obviously not enough to supplement the fuel with enough oxygen for combustion, resulting in serious ash accumulation in the tail heating area and serious combustion slagging problems. In addition, the low calorific value of biomass fuel varies greatly due to different moisture contents, while the high calorific value is not much different. Biomass fuel has a high volatile matter content. There are many kinds of metal elements in the ash of biomass fuel, and there is no fixed ash melting point; the ash particles of biomass fuel have a small density and are more easily carried by the flue gas, and slag is easy to form on the convection heat exchange tube bundle at the furnace outlet. The slag is hard and difficult to clean, which affects the heat transfer effect. As a result, biomass direct-fired power generation units face difficulties in loading, severe high-temperature corrosion, and poor operating reliability, which limits the boiler parameters and restricts the scale of the unit; in addition, in southern my country, due to the variety of biomass and the influence of humid and rainy weather, biomass fuels have a high water content, and there are common problems such as difficult to control the combustion of biomass boilers. Summary of the invention

[0009] The present application proposes a method and device for local oxygen enrichment and precise combustion support for biomass boilers, which has the advantages of local oxygen enrichment and precise combustion support, and is used to solve the problem of difficult control of combustion in biomass boilers mentioned in the above background technology.

[0010] To achieve the above purpose, the present application adopts the following technical solution: a local oxygen-enriched precise combustion method for a biomass boiler, comprising the following steps:

[0011] S1. Biomass is fed into the wind chamber above the grate furnace through a hopper, and the wind chamber is used to supply air to the bottom of the biomass to achieve combustion.

[0012] S2. Use water-cooled wall tubes to absorb heat in the furnace, control and reduce the temperature of the furnace inner wall, and prevent high-temperature damage to the furnace wall.

[0013] S3. Insert a high-temperature gas intake pipe from above the grate ash port to extract high-temperature gas. After adjusting the temperature to the design temperature through the atmosphere, the dust is filtered out through a high-temperature gas filter.

[0014] S4. The filtered high-temperature gas is introduced into the gas ejector, mixed with the oxygen-rich gas from the oxygen source, and pressurized to the designed oxygen-rich flow, concentration, temperature and pressure by a high-temperature and high-pressure blower.

[0015] S5. Oxygen-enriched gas is sprayed downward at a preset angle to the center of the boiler flame through the oxygen-enriched nozzle assemblies installed on the left and right walls between the front arch and the rear arch of the boiler. The number and angle of the oxygen-enriched nozzle assemblies are determined according to the load size of the boiler to increase the center temperature of the flame, extend the residence time of unburned materials, promote complete combustion, and reduce the excess air coefficient, exhaust temperature, exhaust oxygen content and harmful smoke emissions.

[0016] A local oxygen-enriched precision combustion-supporting device for a biomass boiler, the oxygen-enriched nozzle assembly comprising: an oxygen-enriched nozzle shell, an oxygen-enriched nozzle flange is fixed to the outer side, and an oxygen-enriched nozzle nozzle is threadedly connected to the end; a combustion-supporting chamber is opened inside the oxygen-enriched nozzle shell; an air supply ring is fixed to the outer side of the oxygen-enriched nozzle shell, and a gas pipe is fixed to the side of the air supply ring for providing oxygen-enriched air flow to the combustion-supporting chamber; a gas supply hole is opened on the side of the oxygen-enriched nozzle shell.

[0017] Furthermore, an adjusting piston is movably installed inside the oxygen-enriched nozzle housing, an adjusting spring is connected between the adjusting piston and the inner end of the oxygen-enriched nozzle housing, and an air whistle is fixedly installed on the side of the oxygen-enriched nozzle housing.

[0018] Furthermore, the end of the adjusting piston is connected to a supporting shaft seat, and a fan blade is fixedly installed on the end of the supporting shaft seat, and the fan blade is arranged obliquely at the end of the supporting shaft seat; a transposition screw is coaxially movably sleeved inside the adjusting piston, an adjusting screw rod is threadedly connected to the end of the supporting shaft seat, a transmission sleeve is movably installed on the end of the transposition screw, and a column grinding head is movably installed on the end of the transmission sleeve, and the side of the column grinding head and the supporting shaft seat are movably connected via a connecting telescopic frame.

[0019] Furthermore, an elliptical guide sleeve is installed between the inner side of the oxygen-enriched nozzle housing and the end of the regulating piston, and the two elliptical guide sleeves are in a sleeve-type relationship with each other.

[0020] Furthermore, a pressure storage chamber is constructed between the end of the regulating piston and the interior of the oxygen-enriched nozzle housing, a pressure relief hole is opened on the side of the oxygen-enriched nozzle housing, an air relief hole is opened on the side of the regulating piston, a limited motion piston rod is movably installed on the inner side of the regulating piston, a limited motion top spring is connected between the limited motion piston rod and the regulating piston, and a limited motion ring groove is opened on the inner side of the oxygen-enriched nozzle housing.

[0021] Furthermore, the shape of the limiting piston rod is a "cross" shape.

[0022] Furthermore, a center rod is movably installed at the end of the adjusting piston.

[0023] Furthermore, a gear is installed at the end of the center rod, a hook-shaped gear rack is fixedly installed at the end of the limiting piston rod, and the middle part of the center rod is elliptical.

[0024] The present invention has the following beneficial effects:

[0025] 1. The present invention designs the best way to select high-temperature gas and oxygen-enriched mixture according to the characteristics of biomass grate furnace, which not only obtains high-quality oxygen-enriched gas, but also does not need to stop the furnace during installation and maintenance. Therefore, it has the advantages of easy installation, easier operation and maintenance, and can reduce production costs and operating costs.

[0026] 2. It can effectively improve the combustion stability and service life of biomass boilers. The local oxygen-enriched precise combustion-supporting technology has been implemented on fluidized bed boilers for waste incineration: the furnace temperature is generally controlled between 850 and 900°C, coal is added when the normal furnace temperature is lower than 850°C, and coal is stopped when it is higher than 900°C. After the implementation of real-time precise oxygen enrichment and combustion-supporting technology, not only the furnace condition is more stable, the coal is reduced by about 50%, but also the exhaust temperature, O2, CO, NOX and other harmful smoke are significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which constitute a part of the specification, illustrate embodiments disclosed in the present application and, together with the description, serve to explain the principles disclosed in the present application.

[0028] The present application can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0029] Figure 1 Schematic diagram of the local oxygen-enriched precise combustion-supporting system for the biomass grate furnace;

[0030] Figure 2 It is a schematic diagram of the external three-dimensional structure of the oxygen-enriched nozzle assembly;

[0031] Figure 3 It is a schematic diagram of the internal three-dimensional structure of the oxygen-enriched nozzle assembly;

[0032] Figure 4 It is a schematic diagram of the internal planar cross-sectional structure of the oxygen-enriched nozzle assembly;

[0033] Figure 5 It is a schematic diagram of the three-dimensional structure of the supporting shaft seat;

[0034] Figure 6 It is a schematic diagram of the three-dimensional structure of the hook-shaped gear frame and its installation position;

[0035] Figure 7 Schematic diagram of the cross section of each part of the center rod.

[0036] In the figure: 1, air chamber; 2, water-cooled wall tube; 3, regulating valve assembly; 4, hopper; 5, reserved hole for oxygen-enriched nozzle; 6, front arch; 7, rear arch; 8, oxygen source; 9, gas-gas ejector; 10, thermometer 1; 11, high-temperature gas filter; 12, high-temperature and high-pressure fan; 13, oxygen-enriched pressure-stabilizing tank; 14, thermometer 2; 15, oxygen-enriched flowmeter; 16, micro-pressure gauge; 17, oxygen-enriched nozzle assembly; 170, oxygen-enriched nozzle housing; 1700, combustion-supporting chamber; 1701, pressure relief hole; 1702, stop ring groove; 1703, pressure storage chamber; 1704, gas delivery hole; 171, Oxygen-enriched nozzle nozzle; 172, oxygen-enriched nozzle flange; 18, normal temperature regulating valve; 19, high temperature regulating valve; 20, high temperature air intake pipe; 21, PLC electric control cabinet; 22, air supply ring; 220, air transmission pipe; 23, air whistle; 24, regulating piston; 240, regulating spring; 241, air vent; 25, gear; 26, transposition screw; 260, transmission sleeve; 27, column grinding head; 28, center rod; 29, support shaft seat; 290, fan blade; 30, limit piston rod; 300, limit top spring; 31, hook-shaped gear frame; 32, connecting telescopic frame; 33, adjusting screw. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. Embodiment 1

[0038] In order to make biomass boilers more widely used, it is necessary to reduce the ash and slagging of the tail heating area, so as to better save energy, reduce carbon emissions, increase production and improve efficiency. This embodiment 1 introduces the commonly used biomass grate furnace in detail, and other furnace types can be used as a reference (other furnace types such as biomass fluidized bed furnace).

[0039] For grate furnaces, refer to Figure 1 The biomass is fed into the top of the wind chamber 1 through the hopper 4, and the wind chamber 1 is used to supply air to the bottom, so that the biomass burns in the furnace. At the same time, the water-cooled wall tube 2 is used to control the temperature in the furnace, and the temperature of the inner wall of the furnace is effectively reduced by absorbing heat, thereby preventing the furnace wall from being damaged by high temperature. A high-temperature gas extraction pipe 20 is inserted above the ash outlet of the grate to extract high-temperature gas, and after adjusting to the designed temperature through the atmosphere, the high-temperature gas filter 11 is used to filter out dust and then inject it into the gas injector 9, the high-temperature and high-pressure fan 12 and the oxygen-enriched pressure regulating tank 13 to achieve the designed oxygen-enriched flow, concentration, temperature and pressure.

[0040] Secondly, the oxygen-enriched nozzle assembly 17 delivers the enriched oxygen to the flame center of the boiler. Since the oxygen-enriched nozzle assembly 17 sprays downward at an angle and is arranged crosswise on the left and right walls, it can not only increase the flame center temperature, but also move the flame center downward, thereby extending the residence time of unburned materials and making them fully burn, which ultimately leads to a reduction in the excess air coefficient, a significant increase in radiant heat and flame blackness, and a significant decrease in the exhaust gas temperature and exhaust gas oxygen content, CO, NOX and other harmful smoke, so it can reduce the dusting and combustion slagging of the tail heating surface.

[0041] The oxygen-enriched nozzle assembly 17 is installed in the oxygen-enriched nozzle reserved holes 5 on the left and right walls between the front arch 6 and the rear arch 7 of the boiler. The number and angle of the oxygen-enriched nozzle assembly 17 are determined according to the boiler load size, and all the oxygen-enriched nozzles are arranged almost on the same plane.

[0042] In the first embodiment, the oxygen source provided is preferably a pressure swing adsorption vacuum desorption oxygen production equipment (VPSA for short). Since the current VPSA technology is very mature and widely used in petrochemical, steel and other industries at home and abroad, its core component molecular sieve has a long service life and can be operated unmanned.

[0043] More specifically, the high-temperature air extraction pipe 20 provided in the first embodiment is made of a stainless steel pipe, and small holes of about 5 mm are evenly distributed on one end entering the furnace, and the sum of the cross-sectional areas of the holes is at least twice the cross-sectional area of ​​the pipe, thereby reducing the resistance to extracting high-temperature flue gas.

[0044] There are two sets of high temperature gas filters 11, one for operation and one for standby, with high temperature regulating valves 19 installed at both ends for easy switching and cleaning. The high temperature gas filter 11 has a built-in stainless steel filter, preferably placed at about 45°.

[0045] With respect to the oxygen-enriched nozzle reserved hole 5 provided in the first embodiment, for a new furnace, it can be directly reserved; for the reconstruction of an old furnace, the reserved hole can be opened when the furnace is shut down, and a sleeve can be added for sealing, and an adjustment device can be added to the sleeve to adjust the oxygen-enriched nozzle assembly 17; the number of oxygen-enriched nozzle reserved holes 5 is generally between 2 and 10 depending on the boiler load; the downward opening angle of the oxygen-enriched nozzle reserved hole 5 is generally between 5° and 50°.

[0046] The gas ejector 9 in the first embodiment is connected to the high-temperature gas filter 11 at one end and the oxygen source 8 at the other end. The two gases are ejected and enter the high-temperature and high-pressure fan 12. The high-temperature and high-pressure fan 12, the thermometer 14, the oxygen-enriched flowmeter 15 and the micro-pressure gauge 16 are a combination. The high-temperature and high-pressure fan 12 can achieve the required oxygen-enriched flow, temperature and pressure. The regulating valve assembly 3 includes a normal temperature regulating valve 18 and a high-temperature regulating valve 19. The normal temperature regulating valve 18, the high-temperature regulating valve 19 and the thermometer 10 are a combination. The temperature required by the design is achieved by the opening of the normal temperature regulating valve 18 and the high-temperature regulating valve 19. The input port of the oxygen-enriched pressure regulating tank 13 is connected to the exhaust port of the high-temperature and high-pressure fan 12, and its output port is connected to the oxygen-enriched nozzle assembly 17; the PLC electric control cabinet 21 is respectively connected to the oxygen source 8, the high-temperature and high-pressure fan 12 and the oxygen-enriched flowmeter 15, and it has manual, automatic, emergency stop and alarm functions.

[0047] When the first embodiment of the present invention is implemented, the oxygen source 8 adopts VPSA, the oxygen-enriched flow rate is 125 cubic meters per hour, the concentration is about 80%, the power distribution is 55KW, and the area is 50 square meters. The oxygen-enriched flow rate after mixing with the high-temperature flue gas is 800±50 cubic meters per hour, the concentration is about 40±10%, the oxygen-enriched temperature is 300±50℃, the oxygen-enriched pressure is 25±5 kPa, and there are six oxygen-enriched nozzle assemblies 17, three of which are arranged crosswise on the left and right walls, and the oxygen-enriched nozzle assemblies 17 are tilted downward by about 35°. Before implementation, the boiler thermal efficiency is about 84%, and the boiler operator has to clean the coke almost every few days. After implementation, the cleaning cycle is reduced by about 30% on average, the boiler load is relatively stable, and the thermal efficiency is increased by about 5%, that is, when burning the same biomass, about 3 tons / hour of steam can be produced. According to 8,000 hours of operation per year, about 24,000 tons of steam can be produced, and the exhaust temperature, exhaust O2, CO, NOX, dioxin and other harmful smoke are significantly reduced. Embodiment 2

[0048] Based on Example 1, please refer to Figure 2 The oxygen-enriched nozzle assembly 17 adopts a combined structure, including an oxygen-enriched nozzle housing 170, an oxygen-enriched nozzle nozzle 171 and an oxygen-enriched nozzle flange 172. The oxygen-enriched nozzle nozzle 171 is threadedly connected to the oxygen-enriched nozzle housing 170. The oxygen-enriched nozzle nozzle 171 can be processed into various specifications to control different oxygen-enriched speeds, which not only makes it easier to adjust the oxygen-enriched pressure to the best, but also reduces the manufacturing cost and is more convenient to replace. The oxygen-enriched nozzle flange 172 is fixed to the outside of the oxygen-enriched nozzle housing 170, so that the entire oxygen-enriched nozzle assembly 17 is fixed to the desired position.

[0049] from Figure 3It can be seen that a combustion-supporting chamber 1700 is opened inside the oxygen-enriched nozzle shell 170, and air is supplied by an air supply ring 22 fixedly installed on the outside, so that oxygen-rich oxygen is sprayed into the furnace through the oxygen-enriched nozzle nozzle 171. Specifically, an air supply ring 22 fastened by bolts is provided on the outside of the oxygen-enriched nozzle shell 170, and an air supply pipe 220 fixed on the side of the air supply ring 22 inputs air flow into the interior thereof, and the air flow is input into the combustion-supporting chamber 1700 through the air supply hole 1704 opened on the side of the oxygen-enriched nozzle shell 170, and finally sprayed out from the oxygen-enriched nozzle nozzle 171.

[0050] In actual application, if the biomass combustion is incomplete or the amount of smoke generated by the combustion is large, these smoke particles may accumulate in the furnace, in the pipe, and at the oxygen-enriched nozzle tip 171. Over time, these accumulated smoke may form blockages, affecting the normal operation of the oxygen-enriched nozzle assembly 17. As a key component for injecting oxygen-enriched air into the furnace, the patency of the oxygen-enriched nozzle tip 171 is crucial to combustion efficiency and flame stability. If the oxygen-enriched nozzle tip 171 is blocked by smoke, the oxygen-enriched air will not be able to be smoothly sprayed into the furnace, thereby affecting the combustion effect and overall performance. In order to alert outsiders whether the oxygen-enriched nozzle tip 171 is blocked, combined with Figure 3 and Figure 4 It can be clearly seen that an adjusting piston 24 is movably installed inside the oxygen-enriched nozzle housing 170, and an adjusting spring 240 is connected between the adjusting piston 24 and the inner end of the oxygen-enriched nozzle housing 170. The adjusting piston 24 is forced by the elastic force of the adjusting spring 240 to have a tendency to push toward the oxygen-enriched nozzle nozzle 171. Under normal circumstances, under the elastic force of the adjusting spring 240, the adjusting piston 24 approaches the oxygen-enriched nozzle nozzle 171, but the end of the adjusting piston 24 will not pass over the gas delivery hole 1704 to prevent the gas delivery hole 1704 from being blocked by the adjusting piston 24. An air whistle 23 relatively far away from the oxygen-enriched nozzle nozzle 171 is fixedly installed on the side of the oxygen-enriched nozzle housing 170. When the airflow passes through the air whistle 23, the air whistle 23 will make a sound to warn external operators that the oxygen-enriched nozzle nozzle 171 here is blocked.

[0051] When the second embodiment is implemented, the oxygen-enriched pressure-regulating tank 13 outputs the oxygen-enriched gas through the gas delivery pipe 220 and the gas delivery hole 1704, and then inputs the oxygen-enriched gas into the combustion-supporting chamber 1700, and then sprays the oxygen-enriched gas into the furnace through the oxygen-enriched nozzle head 171. At this time, the oxygen-enriched nozzle head 171 is relatively unobstructed, and the regulating spring 240 moves the regulating piston 24 relatively close to the oxygen-enriched nozzle head 171 under the action of elastic force, and the gas whistle 23 is blocked by the outer side of the regulating piston 24, and the oxygen-enriched gas flow entering the combustion-supporting chamber 1700 can only be sprayed from the oxygen-enriched nozzle head 171.

[0052] When used for a long time, when the oxygen-enriched nozzle nozzle 171 is blocked, the air flow pressure input into the combustion-supporting chamber 1700 increases, forcing the adjusting piston 24 to squeeze the adjusting spring 240. When the adjusting piston 24 passes over the gas whistle 23, the air flow in the combustion-supporting chamber 1700 is output from the gas whistle 23, and the gas whistle 23 makes a sound, thereby alerting external operators that the oxygen-enriched nozzle assembly 17 here is blocked and needs to be replaced or cleaned. Embodiment 3

[0053] Further improvements are made based on Example 2. Figure 4 and Figure 5 It can be seen that the end of the regulating piston 24 has a support shaft seat 29 connected by a bearing, and a fan blade 290 is fixedly installed at the end of the support shaft seat 29. The fan blade 290 is arranged obliquely at the end of the support shaft seat 29. When the support shaft seat 29 places the fan blade 290 near the gas delivery hole 1704, the oxygen-rich airflow blows the support shaft seat 29, and the airflow flows along the outer side of the support shaft seat 29 to the middle, forcing the fan blade 290 to drive the support shaft seat 29 to rotate counterclockwise. The direction is referenced Figure 5 Similarly, when the support shaft seat 29 drives the fan blade 290 to move to the vicinity of the gas whistle 23, the airflow in the combustion chamber 1700 is blown outward through the gas whistle 23, and the airflow flows from the inside of the support shaft seat 29 to the outside, and finally makes a sound through the gas whistle 23. During this process, the fan blade 290 is affected by the oxygen-rich airflow and deflects clockwise. Therefore, it can be obtained that due to the different flow directions of the oxygen-rich airflow passing through the fan blade 290, the fan blade 290 will drive the support shaft seat 29 to rotate forward / reverse.

[0054] The adjusting piston 24 is coaxially sleeved with a transposition solenoid 26. At the same time, the end of the support shaft seat 29 is threadedly connected with an adjusting screw rod 33 that is abutted against the spiral groove on the outside of the transposition solenoid 26. In combination with the above, when the support shaft seat 29 drives the adjusting screw rod 33 to rotate forward / reverse on the outside of the transposition solenoid 26, the transposition solenoid 26 can be extended / retracted from the inside of the adjusting piston 24. The end of the transposition solenoid 26 is movably mounted with a transmission sleeve 260 located inside the oxygen-enriched nozzle nozzle 171, and the end of the transmission sleeve 260 is movably mounted with a column grinding head 27. Figure 5 It can be seen that three grinding blocks arranged at equal angles are provided at the end of the column grinding head 27. In order to realize the rotation of the column grinding head 27, the side of the column grinding head 27 and the support shaft seat 29 are movably connected via a connecting telescopic frame 32. The connecting telescopic frame 32 can only reciprocate along the central axis of the support shaft seat 29. When the support shaft seat 29 rotates, the connecting telescopic frame 32 can drive the column grinding head 27 to rotate synchronously.

[0055] During specific implementation, under normal conditions, the oxygen-enriched nozzle nozzle 171 is in the on state, and the adjusting piston 24 pushes the fan blades 290 to the gas delivery hole 1704 under the elastic force of the adjusting spring 240. When the oxygen-enriched airflow is input from the air supply ring 22 to the combustion-supporting chamber 1700, the fan blades 290 will rotate forward (the counterclockwise deflection mentioned above), and the connecting telescopic frame 32 is used to drive the column grinding head 27 to rotate synchronously. At the same time, the adjusting screw 33 follows the rotation of the support shaft seat 29, forcing the transposition screw 26 to retract into the adjusting piston 24. During this process, the transmission sleeve 260 pulls the column grinding head 27 into the combustion-supporting chamber 1700, and the connecting telescopic frame 32 shrinks relatively.

[0056] When the oxygen-enriched nozzle head 171 is blocked, the pressure in the combustion-supporting chamber 1700 increases, forcing the adjusting piston 24 to compress the adjusting spring 240. When the fan blade 290 approaches the air whistle 23, the air flow in the combustion-supporting chamber 1700 is discharged through the air whistle 23. At the same time, the air flow forces the fan blade 290 to drive the support shaft seat 29 to rotate in the opposite direction, and the transposition screw 26 extends outward. Since the column grinding head 27 always rotates with the support shaft seat 29, when the transposition screw 26 pushes the column grinding head 27 toward the oxygen-enriched nozzle head 171 through the transmission sleeve 260, the rotating column grinding head 27 grinds the blockage in the jet channel of the oxygen-enriched nozzle head 171, thereby clearing the blockage in the oxygen-enriched nozzle head 171.

[0057] In order to prevent the adjusting piston 24 from rotating synchronously with the supporting shaft seat 29, Figure 3 and Figure 4 It can be seen that an elliptical guide sleeve is installed between the inner side of the oxygen-enriched nozzle housing 170 and the end of the regulating piston 24, and the two elliptical guide sleeves are nested with each other, thereby limiting the regulating piston 24 to reciprocate only along the central axis of the oxygen-enriched nozzle housing 170, avoiding the simultaneous rotation between the regulating piston 24 and the support shaft seat 29, resulting in the inability of the transposition solenoid 26 to be normally retracted and released from the inside of the regulating piston 24. Embodiment 4

[0058] Further improvements based on Example 3 are provided. Figure 3 and Figure 4It can be seen that the left end of the regulating piston 24 and the interior of the oxygen-enriched nozzle housing 170 form a pressure storage chamber 1703, and the side of the oxygen-enriched nozzle housing 170 is provided with a pressure relief hole 1701 for communicating with the outside and the pressure storage chamber 1703. Correspondingly, the side of the regulating piston 24 is provided with an air leakage hole 241. When the right end of the regulating piston 24 passes over the air whistle 23, the fan blade 290 is placed near the air whistle 23, and the air leakage hole 241 is communicated with the pressure relief hole 1701. A limited motion piston rod 30 is movably installed on the inner side of the regulating piston 24. The shape of the limited motion piston rod 30 is a "cross" shape. A limited motion top spring 300 is connected between the limited motion piston rod 30 and the regulating piston 24. The elastic force of the limited motion top spring 300 is used to make the limited motion piston rod 30 relatively close to the inner side of the regulating piston 24 under normal conditions, and its outer end is relatively far away from the inner side of the oxygen-enriched nozzle housing 170. Correspondingly, a limited motion annular groove 1702 is provided on the inner side of the oxygen-enriched nozzle housing 170. When the limited motion piston rod 30 is pushed into the limited motion annular groove 1702, the movement of the regulating piston 24 will be limited.

[0059] In actual application, under normal conditions, the adjusting piston 24 is subjected to the elastic force of the adjusting spring 240 so that the fan blade 290 is placed near the air supply ring 22, the oxygen-enriched nozzle head 171 is not blocked, and the pressure relief hole 1701 allows the outside to communicate with the pressure storage chamber 1703.

[0060] When the oxygen-enriched nozzle nozzle 171 is clogged after long-term use, the air flow pressure in the combustion-supporting chamber 1700 increases, forcing the regulating piston 24 to compress the regulating spring 240. At the same time, when the regulating piston 24 passes over the pressure relief hole 1701, the pressure relief hole 1701 is blocked by the side of the regulating piston 24, and the pressure storage chamber 1703 is in a relatively sealed state at this time. As the regulating piston 24 continuously compresses the regulating spring 240, the regulating piston 24 will also squeeze the air flow in the pressure storage chamber 1703, forcing its pressure to increase. Afterwards, the limit piston rod 30 will compress the limit top spring 300 due to the increased internal pressure of the pressure storage chamber 1703, forcing The limiting piston rod 30 reaches the inner side of the oxygen-enriched nozzle housing 170. As the adjusting piston 24 continues to move to the left, when the limiting piston rod 30 is pushed into the limiting ring groove 1702, the adjusting piston 24 also completely passes over the gas whistle 23. The airflow in the combustion-supporting chamber 1700 is blown out through the gas whistle 23. At the same time, the airflow blows the fan blades 290 to force the column grinding head 27 as described in Example 3. The support shaft seat 29 enables the transposition screw 26 to push the transmission sleeve 260 to move the column grinding head 27 toward the oxygen-enriched nozzle nozzle 171 through the adjusting screw rod 33. The gas whistle 23 enables the column grinding head 27 to grind the blockage at the oxygen-enriched nozzle nozzle 171 through the connecting telescopic frame 32. As the regulating piston 24 is continuously pushed to the right, during this process, a certain air flow pressure is still maintained in the pressure storage chamber 1703, forcing the limiting piston rod 30 to always push into the limiting ring groove 1702. When the transposition solenoid 26 passes over the air leakage hole 241, the external air flow communicates with the pressure storage chamber 1703 through the pressure relief hole 1701 and the air leakage hole 241, and the pressure in the pressure storage chamber 1703 is discharged. At this time, the column grinding head 27 has also extended from the oxygen-enriched nozzle nozzle 171, so that the oxygen-enriched nozzle nozzle 171 is no longer blocked. As the air flow pressure in the pressure storage chamber 1703 leaks out, the limiting piston rod 30 is disengaged from the limiting ring groove 1702 by the elastic force of the limiting top spring 300, and then, the adjusting piston 24 is pushed to the right by the elastic force of the adjusting spring 240 until the fan blade 290 is near the air supply hole 1704 again. As the air flow in the air supply ring 22 pushes the fan blade 290 to rotate, the transposition screw tube 26 pulls the column grinding head 27 back into the oxygen-enriched nozzle housing 170, returning to the normal position mentioned above.

[0061] In the application process of the fourth embodiment, the limiting piston rod 30 is used to limit the oxygen-enriched nozzle head 171. After the blockage is completely cleared, the limiting piston rod 30 is unlocked to ensure that the oxygen-enriched nozzle head 171 can be connected again. In addition, when the regulating piston 24 is placed in the normal position, the column grinding head 27 is retracted into the combustion chamber 1700 through the transposition solenoid 26, so as to prevent the column grinding head 27 from being pushed to the outside all the time and being burned by the flame, resulting in a decrease in its service life. Embodiment 5

[0062] Further improvements are made on the basis of the fourth embodiment. Figure 3 and Figure 4It can be seen that a center rod 28 is movably installed at the end of the adjusting piston 24. When the adjusting piston 24 pushes the fan blades 290 to the vicinity of the air supply ring 22, the end of the center rod 28 is pushed out from the oxygen-enriched nozzle head 171. When the adjusting piston 24 pulls the fan blades 290 to the vicinity of the gas whistle 23, the center rod 28 will be retracted into the combustion-supporting chamber 1700. This method can ensure that after the oxygen-enriched nozzle head 171 is blocked, the airflow in the combustion-supporting chamber 1700 can flow out through the holes reserved by the center rod 28. Since the diameter of the center rod 28 is relatively small, the pressure in the combustion chamber 1700 will increase. When the column grinding head 27 grinds the blockage at the end of the oxygen-enriched nozzle nozzle 171, due to the reserved small hole, which is coaxial with the oxygen-enriched nozzle nozzle 171 and the column grinding head 27, the powder blockage ground by the column grinding head 27 will be output from the small hole to the furnace chamber. This method avoids the situation that after the oxygen-enriched nozzle 171 is completely blocked, the column grinding head 27 grinding from the inside to the outside will cause the grinding particles to The particles are dispersed into the combustion-supporting chamber 1700, and then accumulate in the combustion-supporting chamber 1700, causing the various components in the combustion-supporting chamber 1700 to be affected and unable to move normally. In this way, after the center rod 28 is retracted into the combustion-supporting chamber 1700, there is always airflow output from the oxygen-enriched nozzle nozzle 171 in the combustion-supporting chamber 1700. When the column grinding head 27 grinds on the airflow path, the particles generated by the grinding will also be directly output into the furnace chamber, avoiding the accumulation of ground powder in the combustion-supporting chamber 1700.

[0063] On this basis, reference Figure 4 , Figure 6 and Figure 7 It can be seen that the gear 25 is installed at the left end of the center rod 28, and the gear 25 and the center rod 28 rotate synchronously. The end of the limiting piston rod 30 is fixedly installed with a hook-shaped gear frame 31, and the shape of the hook-shaped gear frame 31 is "C" shaped. When the limiting piston rod 30 is pressed inward by the elastic force of the limiting top spring 300, the end of the limiting piston rod 30 abuts against the outer teeth of the gear 25, thereby limiting the torque of the gear 25. When the torque of the gear 25 is less than the elastic force of the limiting top spring 300, the gear 25 cannot rotate. When the torque of the gear 25 is greater than the elastic force of the limiting top spring 300, the limiting piston rod 30 slides along the outer teeth of the gear 25, and the gear 25 rotates. When the limiting piston rod 30 compresses the limiting top spring 300, the hook-shaped gear frame 31 will press on the outer side of the gear 25, thereby limiting the gear 25 from rotating. Since the middle part of the center rod 28 is elliptical, the transposition screw 26 is sleeved on this part, so that the transposition screw 26 can not only perform axial reciprocating motion along the center rod 28, but also rotate synchronously with the center rod 28. The right end of the column grinding head 27 is circular. When the column grinding head 27 extends from the oxygen-enriched nozzle nozzle 171, the transposition screw 26 is used to drive the center rod 28 to rotate continuously, so that after the carbon deposits are placed at the end of the oxygen-enriched nozzle nozzle 171, the center rod 28 is rotated to avoid aggravation of blockage, and ensure that the center rod 28 can be stably withdrawn into the combustion chamber 1700.

[0064] In actual application, under normal conditions, the regulating piston 24 pushes the blade 290 to the air supply ring 22. At this time, the right circular end of the center rod 28 extends from the oxygen-enriched nozzle nozzle 171, and the oxygen-enriched airflow is input from the air supply ring 22 into the combustion chamber 1700 and ejected from the oxygen-enriched nozzle nozzle 171. As the airflow blows the blade 290 to rotate in the positive direction, the transposition screw 26 will be retracted into the regulating piston 24, and the column grinding head 27 will be pulled back into the combustion chamber 1700 through the transmission sleeve 260. After that, as the regulating screw 33 moves to the right limit of the spiral groove of the transposition screw 26, the regulating screw 33 will push the transposition screw 26 to rotate synchronously. When the transposition screw 26 drives the center rod 28 to rotate, the gear 25 will rotate. When the torque of the gear 25 increases, it will overcome the elastic force of the limit top spring 300, causing the center rod 28 to rotate synchronously with the transposition screw 26.

[0065] With long-term operation, carbon deposits and coking appear at the end of the oxygen-enriched nozzle head 171, which affect the normal discharge of the airflow. In this process, since the center rod 28 always rotates with the transposition screw 26, coking and carbon deposition will not fix the connection between the center rod 28 and the oxygen-enriched nozzle head 171. When the oxygen-enriched nozzle head 171 cannot output the airflow in the combustion-supporting chamber 1700 to the outside, the pressure in the combustion-supporting chamber 1700 will increase.

[0066] As the pressure increases, the regulating piston 24 will compress the regulating spring 240 to the left, and the pressure increase in the pressure storage chamber 1703 will cause the limiting piston rod 30 to compress the limiting top spring 300. When the limiting piston rod 30 reaches the limiting ring groove 1702, the limiting piston rod 30 pulls the hook-shaped gear rack 31 to press on the gear 25, limiting the rotation of the gear 25. At the same time, the end of the center rod 28 is retracted into the combustion chamber 1700, so that a small hole is reserved at the nozzle 171 of the oxygen-enriched nozzle, and the air flow in the combustion chamber 1700 is discharged through the air whistle 23, and the air whistle 23 makes a sound. When the airflow passes through the fan blades 290, the fan blades 290 will rotate in the opposite direction. When the support shaft seat 29 drives the adjusting screw 33 to rotate along the spiral groove on the outer side of the transposition screw tube 26, the transposition screw tube 26 pushes the column grinding head 27 toward the oxygen-enriched nozzle nozzle 171 through the transmission sleeve 260. During the pushing process, the column grinding head 27 always rotates with the support shaft seat 29. The column grinding head 27 pushed outward will grind the blocked part of the oxygen-enriched nozzle nozzle 171. As the airflow in the combustion-supporting chamber 1700 continues to flow from the small hole at the oxygen-enriched nozzle nozzle 171, the ground powder will be transported into the furnace chamber along it.

[0067] When the transposition solenoid 26 moves to the right and passes over the air leakage hole 241, the external air flow passes through the pressure relief hole 1701 and the air leakage hole 241 and communicates with the pressure storage chamber 1703. At this time, the column grinding head 27 also completes the clearing of the oxygen-enriched nozzle nozzle 171. With the elastic force of the adjustment spring 240, the adjustment piston 24 is pushed to the right until the fan blade 290 moves to the vicinity of the air supply ring 22. The air flow blows the fan blade 290 to make the support shaft seat 29 rotate forward. As the air flow pressure in the pressure storage chamber 1703 decreases, the elastic force of the limit spring 300 causes the limit piston rod 30 to push against the gear 2 5, when the support shaft seat 29 drives the adjusting screw rod 33 to rotate forward, it will force the transposition screw tube 26 to be retracted into the adjusting piston 24, and pull the column grinding head 27 to be retracted into the combustion chamber 1700 through the transmission sleeve 260. Since the torque applied to the transposition screw tube 26 is not enough to make the gear 25 overcome the elastic force of the limit spring 300 during this process, the transposition screw tube 26 will not rotate with the adjusting screw rod 33 until it is retracted into the adjusting piston 24. At the same time, the end of the center rod 28 is pushed out through the adjusting piston 24 and placed again at the end of the oxygen-enriched nozzle nozzle 171. When the adjusting screw rod 33 moves to the right spiral groove of the transposition screw tube 26, the torque of the transposition screw tube 26 driven by the adjusting screw rod 33 increases, so that the gear 25 overcomes the elastic force of the limit spring 300, and the center rod 28 can continue to rotate.

Claims

1. A local oxygen-enriched precise combustion-supporting method for a biomass boiler, characterized in that: The invention comprises a local oxygen-enriched precise combustion-supporting device for a biomass boiler, the device comprising: The oxygen-enriched nozzle assembly (17) comprises: An oxygen-enriched nozzle housing (170) has an oxygen-enriched nozzle flange (172) fixed to its outer side and an oxygen-enriched nozzle nozzle (171) threadedly connected to its end; A combustion-supporting chamber (1700) is provided inside the oxygen-enriched nozzle housing (170); An air supply ring (22) is fixed to the outside of the oxygen-enriched nozzle housing (170), and a gas delivery pipe (220) is fixed to the side of the air supply ring (22) for providing an oxygen-enriched air flow to the combustion-supporting chamber (1700); A gas delivery hole (1704) is provided on the side of the oxygen-enriched nozzle housing (170); An adjusting piston (24) is movably installed inside the oxygen-enriched nozzle housing (170), an adjusting spring (240) is connected between the adjusting piston (24) and the inner end of the oxygen-enriched nozzle housing (170), and an air whistle (23) is fixedly installed on the side of the oxygen-enriched nozzle housing (170); The end of the regulating piston (24) is connected to a support shaft seat (29), and a fan blade (290) is fixedly mounted on the end of the support shaft seat (29), and the fan blade (290) is arranged obliquely at the end of the support shaft seat (29); A transposition solenoid (26) is coaxially movably sleeved inside the regulating piston (24), an adjusting screw rod (33) is threadedly connected to the end of the supporting shaft seat (29), a transmission sleeve (260) is movably mounted on the end of the transposition solenoid (26), and a column grinding head (27) is movably mounted on the end of the transmission sleeve (260), and a side portion of the column grinding head (27) and the supporting shaft seat (29) are movably connected via a connecting telescopic frame (32); An elliptical guide sleeve is installed between the inner side of the oxygen-enriched nozzle housing (170) and the end of the regulating piston (24), and the two elliptical guide sleeves are in a sleeve-type relationship with each other; The following steps are also included: S1, biomass is fed into the upper part of the wind chamber (1) of the grate furnace through the feeding hopper (4), and air is supplied to the bottom of the biomass by the wind chamber (1) to achieve combustion; S2, using the water-cooled wall tube (2) to absorb the heat in the furnace, control and reduce the temperature of the furnace inner wall, and prevent the furnace wall from being damaged by high temperature; S3, inserting a high-temperature gas extraction pipe (20) from above the grate ash outlet to extract high-temperature gas, adjusting the temperature to the design temperature through the atmosphere, and filtering out dust through a high-temperature gas filter (11); S4, introducing the filtered high-temperature gas into the gas ejector (9), mixing it with the oxygen-enriched gas from the oxygen source (8), and pressurizing it to the designed oxygen-enriched flow rate, concentration, temperature and pressure through the high-temperature and high-pressure blower (12); S5. Oxygen-enriched gas is sprayed downward at a preset angle to the center of the boiler flame through oxygen-enriched nozzle assemblies (17) installed on the left and right walls between the front arch (6) and the rear arch (7) of the boiler. The number and angle of the oxygen-enriched nozzle assemblies (17) are determined according to the load size of the boiler to increase the center temperature of the flame, prolong the residence time of unburned materials, promote complete combustion, and reduce the excess air coefficient, exhaust gas temperature, exhaust gas oxygen content and harmful smoke emissions.

2. The local oxygen-enriched precise combustion-supporting method for a biomass boiler according to claim 1 is characterized in that: A pressure storage chamber (1703) is constructed between the end of the regulating piston (24) and the interior of the oxygen-enriched nozzle housing (170); a pressure relief hole (1701) is provided on the side of the oxygen-enriched nozzle housing (170); an air relief hole (241) is provided on the side of the regulating piston (24); a limited motion piston rod (30) is movably installed on the inner side of the regulating piston (24); a limited motion top spring (300) is connected between the limited motion piston rod (30) and the regulating piston (24); and a limited motion annular groove (1702) is provided on the inner side of the oxygen-enriched nozzle housing (170).

3. The local oxygen-enriched precise combustion-supporting method for a biomass boiler according to claim 2 is characterized in that: The limiting piston rod (30) is in the shape of a cross.

4. The local oxygen-enriched precise combustion-supporting method for a biomass boiler according to claim 2, characterized in that: A center rod (28) is movably mounted on the end of the regulating piston (24).

5. The local oxygen-enriched precise combustion-supporting method for a biomass boiler according to claim 4 is characterized in that: A gear (25) is installed at the end of the center rod (28), a hook-shaped gear rack (31) is fixedly installed at the end of the limiting piston rod (30), and the middle part of the center rod (28) is elliptical.

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