Suspension combustion method based on carbon powder

Abstract

The present invention relates to a suspended combustion method based on carbon powder, and belongs to the technical field of suspended combustion. It includes: step one, fuel preparation, grinding raw coal into coal powder through a coal mill; step two, coal powder transportation, using air as a carrier, and transporting the ground coal powder from the nozzle to the combustion chamber through a pipeline; by installing a cutting circle linkage device on the combustion chamber, the nozzle can automatically find the cutting circle; step three, coal powder injection and suspension, the coal powder is sprayed into the combustion chamber in the form of airflow through the nozzle of the burner; step five, combustion product treatment, the ash and slag falling during the combustion process are discharged by liquid slag discharge. Step six, gas emission treatment, the exhaust gas generated by the combustion is sent to the waste treatment device through the upper exhaust channel for treatment to reduce the emission of pollutants. The present invention provides a suspended combustion method based on carbon powder, which has more complete combustion and reduces the loss of excess energy.

Description

Technical Field

[0001] The invention relates to a suspension combustion method based on carbon powder, belonging to the technical field of suspension combustion. Background Art

[0002] A coal-fired boiler is a thermal energy device that uses coal as fuel. It heats water into high-temperature, high-pressure steam by burning coal, which is used to drive turbine generator sets or heating equipment, etc. Coal-fired boilers have the characteristics of simple structure, low investment cost, and easy use. They are currently a type of boiler widely used in industrial production.

[0003] Suspended combustion technology refers to a technology that sprays solid or liquid fuel into the combustion chamber through airflow, forms suspended fuel particles in the combustion chamber, and uses the dense contact between high-temperature airflow and fuel particles to achieve efficient combustion. Its working principle is to make the fuel particles form a suspended state in the high-temperature airflow in the gas flow injected into the combustion chamber, and efficiently contact with oxygen to achieve a good combustion effect.

[0004] The existing Chinese invention patent with publication number CN115342343A is a coal-fired boiler energy-saving device and method, which relates to the technical field of coal-fired boilers. This coal-fired boiler energy-saving device includes a coal-fired boiler body installed on a bottom plate, a feed pipe is installed on the coal-fired boiler body, a support plate is fixed on the bottom plate, an operating box is fixed on the support plate, and a sleeve is installed on the operating box. This coal-fired boiler energy-saving device pushes the push pipe into the coal-fired boiler body, starts the second motor, and drives the push pipe to rotate by the second motor. During the rotation of the push pipe, the sieved fuel inside the push pipe is separated and sprayed from each first through hole by the action of centrifugal force, and the granular coal sprayed out increases the fuel to an appropriate amount of suspended combustion.

[0005] In the process of implementing the technical solution of this application, the inventor discovered that there are at least the following technical problems in the prior art:

[0006] When using a large boiler, such as a combustion chamber with a volume of 19082.3mm long * 19082.3mm wide * 18092.3mm deep, using different processes will result in very different energy losses, so a more suitable process is provided. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a carbon powder-based suspension combustion method, which can achieve more complete combustion and reduce the loss of excess energy.

[0008] The carbon powder-based suspension combustion method of the present invention comprises:

[0009] Step 1: fuel preparation: crush the raw coal into coal blocks with a size of 1um to 2cm by a crusher, and feed the crushed coal blocks into a coal mill to grind them into coal powder with a size of 1μm to 500μm;

[0010] Step 2: Coal powder transportation: using air as a carrier, the ground coal powder is transported from the nozzle to the combustion chamber through a pipeline. During the transportation process, the mixing ratio of coal powder and air needs to be controlled to ensure that the coal powder can be evenly suspended in the combustion chamber.

[0011] By installing a cutting circle linkage device on the combustion chamber, the nozzle can automatically find the cutting circle;

[0012] Step 3: Coal powder injection and suspension: The coal powder is sprayed into the combustion chamber in the form of airflow through the burner nozzle. The coal powder is suspended in the furnace under the action of the airflow. The suspended coal powder is fully mixed and contacted with the hot air and flame in the combustion chamber.

[0013] Step 4: Control the combustion of pulverized coal. By controlling the injection of secondary air, the combustible substances in the pulverized coal particles react chemically with the oxygen in the air, releasing a large amount of heat. The heat generated by the combustion and part of the combustion products are discharged with the airflow in the combustion chamber.

[0014] Step five, combustion product treatment, the ash dropped during the combustion process is discharged by means of liquid slag discharge, liquid discharge treatment, wastewater recovery, and the wastewater is treated by sedimentation and filtration to meet the requirements of reuse.

[0015] Step six, gas emission treatment, the waste gas generated by combustion is sent to the waste treatment device through the upper exhaust channel for treatment to reduce the emission of pollutants.

[0016] Furthermore, in step one, the crushed coal blocks are dried and transported by a screw conveyor, and are dried during the transportation process.

[0017] Furthermore, in step one, the crushed coal blocks are ground into coal powder with a size between 1 μm and 100 μm.

[0018] Furthermore, the sealing air used by the coal mill is arranged in at least two channels, one of which is a fire detection channel extending directly into the combustion chamber.

[0019] Furthermore, before the pulverized coal is injected in step three, the nozzles of the burners at the four corners need to be aligned.

[0020] Furthermore, the centering process adopts a tangential circle combustion method, and the tangential circle combustion method adopts four-corner tangential circle combustion.

[0021] Furthermore, oxygen is mixed into the air in step 4, and the oxygen injection amount is 0.3% to 10% of oxygen per volume of air.

[0022] Furthermore, a temperature control system is provided on the inner wall of the combustion chamber for detecting the temperature in the combustion chamber.

[0023] Furthermore, a drainage groove is installed on the bottom surface of the combustion chamber to discharge the burned ash out of the combustion chamber.

[0024] Furthermore, a driving device is provided on one side of the combustion chamber for use with the cutting circle linkage device.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention optimizes the combustion process to ensure that the coal powder can be evenly suspended in the combustion chamber and fully mixed and contacted with the hot air and flame, thereby improving the combustion efficiency and reducing energy loss. In addition, by controlling the injection of secondary air, the combustible substances in the coal powder particles and the oxygen in the air react more efficiently, further improving the combustion efficiency.

[0027] The present invention reduces the time for construction workers to center the nozzle and find the cutting circle by arranging the cutting circle linkage device, thereby reducing the time loss in the production process.

[0028] The present invention adopts two channels for sealing air, thereby realizing the same set of equipment for sealing air and fire detection cooling air, and reducing the two centrifugal fans of the fire detection cooling air system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the combustion chamber structure of an embodiment of the present invention;

[0030] Figure 2 yes Figure 1 A partial enlarged view of the middle part;

[0031] Figure 3 is a top view of a combustion chamber of an embodiment of the present invention;

[0032] Figure 4 is a schematic diagram of the internal structure of a combustion chamber according to an embodiment of the present invention;

[0033] Figure 5 is a front view of a combustion chamber of an embodiment of the present invention;

[0034] Figure 6 yes Figure 5 A partial enlarged view of point B in the middle;

[0035] Figure 7 is a schematic diagram of the base structure of an embodiment of the present invention;

[0036] Figure 8 is a schematic structural diagram of a driving device according to an embodiment of the present invention;

[0037] Fig. 9 is a front view of a driving device according to an embodiment of the present invention;

[0038] Fig.10 yes Fig. 9 Full section view at CC;

[0039] Fig.11 yes Fig.10 A partial enlarged view of point D in the middle;

[0040] Fig.12 This is a diagram of a nozzle centering circle according to an embodiment of the present invention;

[0041] In the figure:

[0042] 1. Combustion chamber; 11. Top plate; 111. Exhaust channel; 12. Support frame; 13. Column; 131. Secondary air duct; 132. Nozzle; 133. Fire detection channel; 134. Articulated column; 135. Articulated plate; 14. Heat insulation board; 15. Refractory base; 151. Drainage trough; 152. Water collection surface; 153. Flushing nozzle; 154. Positioning column; 16. Large cylindrical roller thrust bearing;

[0043] 2. Driving device; 21. Screw; 211. Slider; 22. Elastic coupling; 23. Sleeve; 231. Positioning shaft; 24. Motor; 25. Machine base; 251. Cross plate; 252. Grating scale; 253. Support seat; 254. Tapered roller bearing; 255. Annular pressing piece; 26. Connecting plate; 27. Fixed frame; 28. Thrust roller bearing; 29. ​​Self-aligning roller bearing;

[0044] 3. Cutting circle linkage device; 31. Connecting rod; 32. Rotating disk;

[0045] 100.Cylinder cross section. DETAILED DESCRIPTION

[0046] Example 1

[0047] like Figures 1 to 12 As shown, the carbon powder-based suspension combustion method of the present invention comprises:

[0048] Step 1: fuel preparation: crush the raw coal into coal blocks with a size of 1um to 2cm by a crusher, and feed the crushed coal blocks into a coal mill to grind them into coal powder with a size of 1μm to 500μm;

[0049] Step 2: coal powder transportation, using air as a carrier, the ground coal powder is transported from the nozzle 132 to the combustion chamber 1 through the pipeline. During the transportation process, the mixing ratio of coal powder and air needs to be controlled to ensure that the coal powder can be evenly suspended in the combustion chamber 1;

[0050] By installing a cutting circle linkage device 3 on the combustion chamber 1, the nozzle 132 can automatically find the cutting circle; the combustion chamber 1 includes a rotatable column 13, and the columns 13 are respectively located at the four corners of the combustion chamber 1. The column 13 is located on one side inside the combustion chamber 1 and is provided with a secondary air duct 131, a fire detection channel 133 and a nozzle 132 located between the secondary air duct 131 and the fire detection channel 133. The upper end of the column 13 is hinged with a support frame 12, the support frame 12 is used to connect the four columns 13, and the support frame 12 is installed with a cutting circle linkage device 3.

[0051] A heat insulation board 14 is installed between the columns 13, and a plurality of flushing nozzles 153 are distributed at the lower end of the heat insulation board 14. A refractory base 15 is provided at the bottom end of the combustion chamber 1, and a water collecting surface 152 is provided on the refractory base 15. A drainage groove 151 is provided at the lowest end of the water collecting surface 152.

[0052] Vertically arranged positioning columns 154 are installed on the four corners of the base, and large-scale thrust cylindrical roller bearings 16 are installed on the positioning columns 154 . The upper end of the large-scale thrust cylindrical roller bearing 16 is installed with a column 13 to reduce the rotation resistance of the column 13 .

[0053] A top plate 11 is installed at the upper end of the combustion chamber 1 , and an exhaust passage 111 is opened in the center of the top plate 11 .

[0054] The circular cutting linkage device 3 comprises a rotating disk 32, the outer ring of the rotating disk 32 is respectively hinged with four connecting rods 31, and the other end of the connecting rod 31 is hinged to the top of the column 13;

[0055] like Figure 3 As shown, a hinged column 134 is provided at the top of the column 13, and the hinged column 134 is eccentrically arranged. The hinged columns 134 of the diagonal columns 13 are symmetrically arranged about the center of the circle, and the eccentric positions of the hinged columns 134 on the diagonal columns 13 are the same; Figure 3 As shown in β1 and β2, β1 is larger than β2, and β1 and β2 are the distances from the hinge column 134 to the axis of the column 13;

[0056] The hinged posts 134 on the other pair of upright posts 13 have a larger eccentric distance, which facilitates the circle cutting operation.

[0057] At this time, rotating one column 13 can cause the other three columns 13 to move correspondingly through the rotating disk 32 at the upper end, thereby realizing linkage.

[0058] Step 3: Coal powder is sprayed and suspended. The coal powder is sprayed into the combustion chamber 1 in the form of airflow through the burner nozzle 132. The coal powder is suspended in the furnace under the action of the airflow. The suspended coal powder is fully mixed and contacted with the hot air and flame in the combustion chamber 1.

[0059] Step 4, coal powder combustion control, by controlling the injection of secondary air so that the combustible substances in the coal powder particles react chemically with the oxygen in the air, releasing a large amount of heat, and the heat generated by the combustion and part of the combustion products are discharged with the airflow in the combustion chamber 1;

[0060] Step five, combustion product treatment, the ash dropped during the combustion process is discharged by means of liquid slag discharge, liquid discharge treatment, wastewater recovery, and the wastewater is treated by sedimentation and filtration to meet the requirements of reuse.

[0061] Step six, gas emission treatment, the waste gas generated by combustion is sent to the waste treatment device through the upper exhaust channel 111 for treatment to reduce the emission of pollutants.

[0062] In step one, the crushed coal blocks are dried and transported by a screw conveyor, and are dried during the transportation process.

[0063] In step 1, the crushed coal blocks are ground into coal powder with a size between 1 μm and 100 μm.

[0064] The sealing air used by the coal mill is arranged in at least two channels, one of which is the fire detection channel 133 that directly extends into the combustion chamber 1. The fire detection cooling air system is mainly composed of two centrifugal fans in parallel. When the unit is operating normally, one fan is in operation and the other is in standby, providing a stable and reliable cooling and purge air source for the fire detection monitoring systems of various parts of the boiler. However, in actual operation, the boiler fire detection cooling fan often experiences abnormal conditions such as vibration, abnormal noise, and filter blockage, which seriously affects the safe use of the fire detection cooling air. The coal mill sealing air with similar temperature and pressure is used to replace the fire detection cooling fan air source, which can realize the shutdown of all fire detection cooling fans for standby, ensuring the safe operation of the boiler, stopping the fire detection cooling fan and saving electricity costs.

[0065] Before the pulverized coal is injected in step three, the nozzles 132 of the burners at the four corners need to be centered.

[0066] The centering treatment adopts the tangential combustion method, which is a combustion technology widely used in large boilers. Specifically, the four-corner tangential combustion method is to spray the pulverized coal (primary air) and secondary air into the furnace in a way that is tangent to an imaginary tangential circle at the four corners of the furnace and the center of the furnace, so as to realize the tangential combustion of the pulverized coal. This combustion method has a series of advantages such as good furnace filling, large disturbance, conducive to burning, and low NOX emissions. It is currently an internationally advanced combustion method. The tangential combustion method adopts four-corner tangential combustion. Four-corner combustion generally refers to arranging burners at the four corners of the combustion chamber 1 (furnace) to send fuel into the furnace for combustion. In boilers with direct current burners, the burners are usually arranged at the four corners of the furnace. When the four primary air flows reach the center of the furnace, a rotating tangential circle will be formed, and with the orientation of the induced and supplied air flows, a vortex-shaped combustion airflow will be generated from bottom to top. At the same time, the four primary air flows rush to the downstream primary air burner, which is conducive to the ignition of the pulverized coal.

[0067] like Fig.11 As shown, here, tangential combustion is performed using an imaginary cylindrical cross section 100, and the nozzles 132 at the opposite corners are the circumscribed circles of the cylinder, while the nozzles 132 at the other opposite corners are aligned with the inscribed circles.

[0068] In step 4, oxygen is mixed into the air, and the oxygen injection amount is 0.3% to 10% of oxygen per volume of air. Oxygen can play a role in supporting combustion, making the combustion more complete.

[0069] A temperature control system is provided on the inner wall of the combustion chamber 1 for detecting the temperature inside the combustion chamber 1. The temperature control system is a non-contact infrared thermometer extending into the interior of the heat insulation layer.

[0070] A drainage groove 151 is installed on the bottom surface of the combustion chamber 1 to discharge the burned ash out of the combustion chamber 1 .

[0071] A driving device 2 for use with the circular cutting linkage device 3 is provided on one side of the combustion chamber 1. The driving device 2 includes a fixed frame 27, on which a connecting plate 26 is installed, on which a base 25 is rotatably installed, and on which a motor 24 is installed. The motor 24 is an AC servo motor, and an output end of the motor 24 is connected to a screw rod 21, on which an adapted slider 211 is installed, and one side of the slider 211 is hinged to a hinge plate 135 on the outer wall of the column 13.

[0072] like Figure 2 or Figure 8As shown, the output end of the motor 24 is key-connected with a sleeve 23, and a positioning shaft 231 is also installed between the sleeve 23 and the output end of the motor 24. The positioning shaft 231 prevents the sleeve 23 from sliding out under force. An elastic coupling 22 is installed at one end of the sleeve 23 away from the motor 24, and a screw 21 is installed at the other end of the elastic coupling 22. The screw 21 can be self-locked through the upper thread, thereby fixing the column 13. The use of the elastic coupling 22 can better adapt to impact and prevent damage to the motor 24.

[0073] like Figure 8 to Figure 11 As shown, a positioning column 154 is provided at the lower end of the connecting plate 26, and a mounting tube is provided on the machine base 25. The positioning column 154 extends into the mounting tube for installation. A self-aligning roller bearing 29 is installed between the positioning column 154 and the mounting tube. The self-aligning roller bearing 29 is mounted on the positioning column 154. A thrust roller bearing 28 is also mounted on the upper end of the positioning column 154. The thrust roller bearing 28 is used to bear the gravity of the machine base 25 and the motor 24, so that the motor 24 can rotate conveniently during operation.

[0074] An outwardly extending transverse plate 251 is installed on the machine base 25, and a support seat 253 is installed on the transverse plate 251. Tapered roller bearings 254 are symmetrically installed in the support seat 253. The tapered roller bearings 254 are used in pairs. An annular pressing piece 255 for axially positioning the tapered roller bearings 254 is also installed on the support seat 253. The annular pressing piece 255 is threadedly connected to the inner hole of the support seat 253.

[0075] A grating ruler 252 is provided on the horizontal plate corresponding to the slider 211. The grating ruler 252 is used to locate the moving distance of the slider 211, so as to meet the requirements of precise control.

[0076] Working process or working principle:

[0077] The moving distance of the slider 211 is controlled by the grating ruler 252, so that the motor 24 is rotated or stopped accordingly. The size of the cutting circle is determined by the grating ruler 252, thereby driving the column 13 to rotate. The rotation of the column 13 drives the connecting rod 31 to move through the hinged column 134 at the upper end. The connecting rod 31 drives the rotating disk 32 to rotate, thereby correspondingly rotating the other three columns 13, thereby realizing rapid alignment of the inscribed circle and the circumscribed circle of an imaginary cylindrical cross section 100, greatly reducing the time for adjusting the cutting circle.

[0078] The description of the direction and relative position relationship of the structure in the present invention, such as the description of front, back, left, right, up, and down, does not constitute a limitation of the present invention, but is only for the convenience of description.

Claims

1. A suspension combustion method based on carbon powder, characterized in that: include: Step 1: fuel preparation: crush the raw coal into coal blocks with a size of 1um to 2cm by a crusher, and feed the crushed coal blocks into a coal mill to grind them into coal powder with a size of 1μm to 500μm; Step 2: coal powder transportation, using air as a carrier to transport the ground coal powder from the nozzle (132) to the combustion chamber (1) through a pipeline. During the transportation process, the mixing ratio of coal powder and air needs to be controlled to ensure that the coal powder can be evenly suspended in the combustion chamber (1); By installing a cutting circle linkage device (3) on the combustion chamber (1), the nozzle (132) can automatically find the cutting circle; Step 3: coal powder injection and suspension: the coal powder is sprayed into the combustion chamber (1) in the form of an airflow through the burner nozzle (132). The coal powder is affected by the airflow in the furnace and becomes suspended. The suspended coal powder is fully mixed and in contact with the hot air and flame in the combustion chamber (1); Step 4, coal powder combustion control, by controlling the injection of secondary air so that the combustible substances in the coal powder particles react chemically with oxygen in the air, releasing a large amount of heat, and the heat generated by the combustion and part of the combustion products are discharged along with the airflow in the combustion chamber (1); Step 5: Treatment of combustion products: the ash and slag dropped during the combustion process are discharged by means of liquid slag discharge, liquid discharge treatment, and wastewater recovery. The wastewater is treated by sedimentation and filtration to meet the requirements for reuse; Step six, gas emission treatment, the exhaust gas generated by the combustion is sent to the waste treatment device through the upper exhaust passage (111) for treatment to reduce the emission of pollutants; The combustion chamber (1) comprises a rotatable column (13), the columns (13) being respectively located at four corners of the combustion chamber (1), and a secondary air duct (131), a fire detection channel (133) and a nozzle (132) located between the secondary air duct (131) and the fire detection channel (133) being provided on one side of the column (13) located inside the combustion chamber (1), a support frame (12) being hingedly connected to the upper end of the column (13), the support frame (12) being used to connect the four columns (13), and a circular cutting linkage device (3) being installed on the support frame (12); The circular cutting linkage device (3) comprises a rotating disk (32), the outer ring of the rotating disk (32) is respectively hinged with four connecting rods (31), and the other end of the connecting rod (31) is hinged to the top end of the column (13); A hinged column (134) is provided at the top of the column (13), the hinged column (134) is eccentrically arranged, the hinged columns (134) of the diagonal columns (13) are symmetrically arranged, and the eccentric positions of the hinged columns (134) on the diagonal columns (13) are the same; β1 is greater than β2, and β1 and β2 are the distances from the hinged column (134) to the axis of the column (13); The hinged column (134) on the other pair of columns (13) has a larger eccentric distance, which is convenient for the circle cutting operation; At this time, rotating one column (13) can cause the other three columns (13) to move correspondingly through the rotating disk (32) at the upper end, thereby realizing linkage; A driving device (2) for use with the circular cutting linkage device (3) is provided on one side of the combustion chamber (1), the driving device (2) comprising a fixing frame (27), a connecting plate (26) being mounted on the fixing frame (27), a base (25) being rotatably mounted on the connecting plate (26), a motor (24) being mounted on the base (25), the motor (24) being an AC servo motor, a screw rod (21) being connected to the output end of the motor (24), a matching slider (211) being mounted on the screw rod (21), and one side of the slider (211) being hinged to a hinge plate (135) on the outer wall of the column (13); A grating ruler (252) is provided on the horizontal plate corresponding to the slider (211), and the grating ruler (252) is used to locate the moving distance of the slider (211), thereby satisfying precise control.

2. The carbon powder-based suspension combustion method according to claim 1, characterized in that: In step one, the crushed coal blocks are dried and transported by a screw conveyor, and are dried during the transportation process.

3. The carbon powder-based suspension combustion method according to claim 1, characterized in that: In step 1, the crushed coal blocks are ground into coal powder with a size between 1 μm and 100 μm.

4. The carbon powder-based suspension combustion method according to claim 1, characterized in that: The sealing air used by the coal mill is arranged in at least two channels, one of which is a fire detection channel (133) extending directly into the combustion chamber (1).

5. The carbon powder-based suspension combustion method according to claim 1, characterized in that: Before the pulverized coal is injected in step three, the nozzles (132) of the burners at the four corners need to be aligned.

6. The carbon powder-based suspension combustion method according to claim 5, characterized in that: The centering treatment adopts the tangential circle burning method, and the tangential circle burning method adopts four-corner tangential circle burning.

7. The carbon powder-based suspension combustion method according to claim 1, characterized in that: Oxygen is mixed into the air in step 4, and the oxygen injection amount is 0.3% to 10% of oxygen per volume of air.

8. The carbon powder-based suspension combustion method according to claim 1, characterized in that: A temperature control system is provided on the inner wall of the combustion chamber (1) for detecting the temperature in the combustion chamber (1).

9. The carbon powder-based suspension combustion method according to claim 1, characterized in that: A drainage groove (151) is installed on the bottom surface of the combustion chamber (1) for discharging the ash after combustion out of the combustion chamber (1).

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