CN111664577A - Biomass hot blast stove system with cyclone mixer capable of controlling flue gas temperature - Google Patents

Abstract

A biomass hot blast stove system with a cyclone mixer capable of controlling the temperature of flue gas belongs to the field of boilers. The invention aims to solve the problem that the flue gas of the existing biomass hot blast stove burner contains dust particles, so that a hot blast heat exchanger is abraded. The system comprises a biomass hot blast stove unit and a control console; the first settling chamber is communicated with the second settling chamber, a smoke inlet thermometer is arranged at a smoke outlet of the second settling chamber, the second settling chamber is communicated with an air-smoke mixing chamber, a variable-frequency air cooler is arranged in the air-smoke mixing chamber, the air-smoke mixing chamber is communicated with a cyclone mixer, and the cyclone mixer is communicated with a hot air heat exchanger; a PLC controller is arranged in the console; the signal transmission port arranged on the biomass hot blast stove unit is connected with the data transmission port through a data transmission line. The method is mainly used for controlling the biomass hot blast stove.

Description

A biomass hot blast stove system with cyclone mixer to control flue gas temperature

technical field

The invention relates to a biomass hot blast stove control system, in particular to a biomass hot blast stove system with a cyclone mixer capable of controlling the temperature of flue gas.

Background technique

Biomass hot blast stoves usually install a hot blast heat exchanger at the end of the burner to ensure clean hot blast output. Due to the high temperature of the flue gas entering the hot air heat exchanger and the large amount of dust particles contained in the flue gas, it may cause the tube wall of the hot air heat exchanger to overheat, increase the mechanical wear of the heat exchange tubes in the hot air heat exchanger, and reduce the hot air exchange. The service life of the heater is reduced, the efficiency of the biomass hot blast stove is reduced, and the production cost is increased. Therefore, it is necessary to take anti-heat fatigue and anti-wear measures for the hot air heat exchanger.

Due to the high combustion temperature in the biomass hot air burner, the outlet temperature of the burner all exceeds 1000 °C, and the produced flue gas contains a large amount of particulate matter and unburned charcoal. If the high-temperature flue gas containing a large amount of particulate matter and unburned carbon is allowed to enter the hot air heat exchanger, long-term use will inevitably cause thermal fatigue and mechanical wear of the steel of the hot air heat exchanger tube wall and cause premature failure. The secondary combustion of the charcoal will damage the hot air heat exchanger and affect the efficiency of the biomass hot air furnace. Through pre-research, it is found that if the outlet temperature of the burner is controlled at 800-820 °C, the service life of the heat exchanger can be effectively extended.

At present, biomass hot blast stove lacks a system with anti-wear device that can accurately control the temperature of flue gas entering the hot blast heat exchanger to protect the hot blast heat exchanger.

SUMMARY OF THE INVENTION

The present invention is to solve the problem that the existing biomass hot blast stove burner contains dust particles in the flue gas, which causes the wear of the hot blast heat exchanger, and now provides a biomass hot blast stove control system which can automatically control the flue gas temperature.

A biomass hot blast stove control system with automatically controllable flue gas temperature, comprising:

Biomass hot blast stove unit;

The biomass hot blast stove unit comprises a first settling chamber (1), a second settling chamber (2), a smoke inlet thermometer (3), an air-smoke mixing chamber (4), a variable frequency air cooler (5), a cyclone mixer (6), smoke pyrometer (7), hot air heat exchanger (8), biomass burner (18);

The first settling chamber (1) is communicated with the second settling chamber (2), a smoke inlet thermometer (3) is installed at the smoke outlet of the second settling chamber (2), and the second settling chamber (2) It is communicated with the air-smoke mixing chamber (4), the air-smoke mixing chamber (4) is equipped with a variable frequency cooling fan (5), and the air-smoke mixing chamber (4) is communicated with the smoke inlet (601) of the cyclone mixer (6). The mixer (6) is provided with an ash discharge port (605), the ash discharge port is oriented vertically downward, and the smoke outlet (604) of the cyclone mixer (6) is communicated with the hot air heat exchanger (8). The smoke outlet of (6) is provided with a smoke thermometer (7);

The system also includes a console (9);

A PLC controller (12) is arranged inside the console (9), and a data transmission port (15) is also arranged on the console (9);

The biomass hot blast stove unit is provided with a signal transmission port (17), and the signal transmission port (17) is connected with the data transmission port (15) through a data transmission line (16).

beneficial effect

The system of the invention is equipped with a cyclone mixer, which uses the principle of airflow rotation to fully mix the cold air with the flue gas, so that the temperature distribution of the mixed flue gas can be uniform, and at the same time, most of the dust particles in the flue gas can be removed, and the number of hot air heat exchangers can be reduced. mechanical wear and prolong the service life of the hot air heat exchanger.

The cyclone mixer in the system of the present invention can remove the unburned char in the flue gas, and can effectively prevent the char from accumulating and secondary combustion in the flue gas pipe of the hot air heat exchanger and causing damage to the hot air heat exchanger.

The invention can realize fully automatic air distribution, and automatically adjust the air distribution according to the temperature measured by the thermometer. Ensure that biomass hot blast stoves can operate safely and maximize energy utilization.

The biomass hot blast stove system of the invention controls the operation of the variable frequency cooling fan of the biomass hot blast stove through the PLC controller, and through the control of the temperature control system, the temperature of the flue gas can be lowered to 800-820° C., and the excessive temperature can be prevented from entering the hot blast heat exchanger. It leads to premature heat loss, reduces the thermal fatigue problem of the hot blast heat exchanger, and improves the safety and efficiency of the biomass hot blast stove.

Description of drawings

Figure 1 is a schematic diagram of the system structure;

Fig. 2 is the system work flow chart;

Fig. 3 is the structural representation of cyclone mixer;

Figure 4 is a schematic structural diagram of a hot air heat exchanger;

FIG. 5 is a flow chart of temperature adjustment control.

In the figure: 1. First settling chamber, 2. Second settling chamber, 3. Inlet smoke thermometer, 4. Air and smoke mixing chamber, 5. Variable frequency air cooler, 6. Cyclone mixer, 601. Cyclone mixer Smoke inlet, 602. Cylindrical air and smoke mixing chamber, 603. Conical air and smoke mixing chamber, 604. Cyclone mixer smoke outlet, 605. Ash discharge port, 7. Smoke temperature measuring instrument, 8. Hot air heat exchanger, 801. Heat exchanger smoke inlet, 802. Smoke pipe, 803. Heat exchanger smoke outlet, 804. Cold air inlet, 805. Hot air outlet, 9. Console, 10. Industrial display, 11. Frequency converter, 12. PLC controller, 13. Control keyboard, 14. Emergency brake valve, 15. Data transmission port, 16. Data transmission line, 17. Signal transmission port, 18. Biomass burner

Detailed ways

Embodiment 1: Referring to Figures 1-4 to illustrate this embodiment, a biomass hot blast stove control system with automatically controllable flue gas temperature includes:

Biomass hot blast stove unit;

The biomass hot blast stove unit includes a first settling chamber 1, a second settling chamber 2, a smoke inlet thermometer 3, an air-smoke mixing chamber 4, a variable frequency air cooler 5, a cyclone mixer 6, and a smoke outlet thermometer 7. , hot air heat exchanger 8, biomass burner 18;

The first settling chamber 1 is communicated with the second settling chamber 2, a smoke inlet thermometer 3 is installed at the smoke outlet of the second settling chamber 2, and the second settling chamber 2 is communicated with the air-smoke mixing chamber 4. The mixing chamber 4 is equipped with a variable frequency cooling fan 5, and the air supply volume of the variable frequency cooling fan 5 is controlled by the frequency converter 11. The air-smoke mixing chamber 4 is communicated with the smoke inlet 601 of the cyclone mixer 6, and the cyclone mixer 6 is provided with Ash discharge port 605, the direction of the ash discharge port is vertical downward, the smoke outlet 604 of the cyclone mixer 6 is communicated with the hot air heat exchanger 8, and the smoke outlet of the cyclone mixer 6 is provided with a smoke outlet thermometer 7 , used to detect the smoke temperature to determine the air volume of the variable frequency cooling fan 5 .

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the system further includes a console 9;

The inside of the console 9 is provided with a PLC controller 12, and the PLC controller 12 is a PLC controller of all brands and models currently owned; all buttons for controlling the system are arranged on the control keyboard 13, which is convenient for work. Personnel operation; the console 9 is also provided with a data transmission port 15 ; the biomass hot blast stove unit is provided with a signal transmission port 17 , and the signal transmission port 17 is connected with the data transmission port 15 through a data transmission line 16 .

Other steps and parameters are the same as in the specific embodiment.

Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that, as shown in FIG. 3 , the main body of the cyclone mixer 6 is a cavity formed by a cylinder and a cone, and the cylinder and the cone are part of a cavity. They are respectively denoted as cylindrical air-smoke mixing chamber 602 and conical air-smoke mixing chamber 603; the smoke inlet 601 is arranged on the cylindrical side wall shell of the cylindrical air-smoke mixing chamber 602, and the smoke outlet 604 is arranged above the cylinder of the cylindrical air-smoke mixing chamber 602 The ash discharge port 605 is the conical port of the conical air-smoke mixing chamber.

Other steps and parameters are the same as in the first or second embodiment.

Embodiment 4: The difference between this embodiment and one of Embodiments 1 to 3 is that, as shown in FIG. 4 , a heat exchanger smoke inlet 801 is provided on the upper left side of the side wall shell of the hot air heat exchanger 8; The smoke pipe 802 is arranged inside the hot air heat exchanger 8, and the upper nozzle of the smoke pipe 802 is connected to the heat exchanger smoke inlet 801; the hot air outlet 805 is provided on the upper right side of the side wall shell of the hot air heat exchanger 8; The cold air inlet 804 is arranged at the lower left of the side wall shell of the hot air heat exchanger 8 ;

Other steps and parameters are the same as one of the first to third embodiments.

Embodiment 5: The difference between this embodiment and one of Embodiments 1 to 4 is that the console 9 is provided with an industrial display 10 , a frequency converter 11 , a control keyboard 13 and an emergency braking valve 14 .

Other steps and parameters are the same as one of Embodiments 1 to 4.

Embodiment 6: The difference between this embodiment and one of Embodiments 1 to 5 is that the PLC controller 12 is used to receive and send all collected information and control instructions.

Other steps and parameters are the same as one of the specific embodiments 1 to 5.

Embodiment 7: The difference between this embodiment and one of Embodiments 1 to 6 is that when an uncontrollable failure occurs in the system, the emergency braking valve 14 can quickly stop all the work of the biomass hot blast stove, ensuring the biomass hot blast stove. and staff safety.

Other steps and parameters are the same as one of Embodiments 1 to 6.

Now in conjunction with Fig. 2, the working principle of the present invention is described:

The high-temperature flue gas from the tail of the biomass burner 18 will enter the first settling chamber 1 and the second settling chamber 2 in turn, and the dust above 50 μm in the flue gas will be removed by two gravity settling methods; The high-temperature flue gas temperature after two gravity dust removal is detected, and then enters the air-smoke mixing chamber 4, and the switch of the variable frequency air cooler 5 is controlled by the flue gas temperature value measured by the flue gas thermometer 3. The temperature value detected by the thermometer 3 will determine the initial air supply volume of the variable frequency cooling fan 5. The variable frequency cooling fan 5 is divided into three gears: 1, 2, and 3. The measured temperature is used as the opening standard for the variable frequency cooling fan 5. ;

The biomass hot blast stove starts to run. When it is detected that the flue gas temperature is below 800°C, the PLC controller 12 will forcibly turn off the variable frequency cooling fan 5 until the flue gas temperature is higher than 800°C again, and then turn on the variable frequency cooling fan. Prevent the flue gas temperature from falling too low, resulting in the loss of heat energy that is not fully utilized;

When the flue gas temperature measured by the smoke inlet thermometer 3 is higher than 800°C, it will check again whether the flue gas temperature is higher than 900°C; if the flue gas temperature is lower than 900°C, the inverter 11 controls the variable frequency cooling fan 4. Run in the 1st gear, and send a small amount of cold air to cool the flue gas, and then enter the cyclone mixer 6; when the flue gas temperature monitored by the flue gas thermometer 3 is higher than 900 ℃, it will be detected again. Whether the flue gas temperature is higher than 1000°C; if the flue gas temperature is lower than 1000°C, the inverter 11 controls the variable frequency cooling fan 4 to run in the 2nd gear, and sends more cold air to cool the flue gas, and then enters the In the cyclone mixing chamber 6; if the flue gas temperature is higher than 1000 ℃, the frequency converter 11 controls the variable frequency cooling fan 4 to operate in the 3rd gear, and sends a large amount of cold air to cool the flue gas, and then enters the cyclone mixer 6 ;

The mixed flue gas enters the cyclone mixer 6 from the smoke inlet 601 of the cyclone mixer, and makes a circular motion inside the cyclone mixer to form a rotating airflow, so that the mixed flue gas is fully mixed to ensure uniform temperature distribution of the mixed flue gas, so as to avoid entering the hot air exchange. The mixed flue gas of the heat exchanger 8 causes damage to the hot air heat exchanger 8 due to uneven temperature distribution; the swirling airflow spirals downward along the wall of the cyclone mixer 6; the mixed flue gas enters the cyclone mixer 6 first in the cylindrical mixing Circular motion is performed in the bin 602, and the spiral flows downward; when it reaches the conical mixing bin 603, due to the shape of the cone, the spiral airflow will shrink to the center, and the tangential acceleration will continue to increase; After the center, the spiral airflow will reverse upward and move upward, and finally be discharged from the cyclone mixer smoke outlet 604 into the hot air heat exchanger 8;

Using the principle of centrifugal force generated when the gas rotates, the centrifugal force of the dust particles in the cyclone mixer is:

Among them, m _p represents the mass of the particle, in kg; r represents the radius of gyration of the particle, in m; u represents the tangential velocity at the radius of gyration r, in m/s; d _p represents the particle size, in μm; ρ _p represents the material density of the particle;

The resistance to the particle is:

F _s =3πμ _g u _t d _p

Among them, μ _g is the fluid dynamic viscosity of the gas phase; u _t is the terminal settling velocity, in m/s;

In the process of separation, the centrifugal force and resistance of the sub is balanced, so we can get:

Therefore, the final settling velocity of the particles is:

The mixed flue gas from the cyclone mixer 6 will enter the flue gas pipe 802 in the hot air heat exchanger 8 through the heat exchanger smoke inlet 801, and the cold air will enter the hot air heat exchanger 8 through the cold air inlet 804; The thermal principle is to transfer the heat in the mixed flue gas to the cold air through the wall of the flue pipe, and heat the cold air into hot air; the heated hot air will be discharged through the hot air outlet 805, and the mixed flue gas will be discharged from the heat exchanger. The cigarette port 803 is discharged;

At the same time, the cyclone mixer also has the function of dust removal. The centrifugal force generated by the rotating airflow can remove the dust particles in the mixed flue gas, and the dust particles will be discharged from the ash discharge port 605 to reduce the mechanical wear of the hot air heat exchanger 8; in the cyclone mixer The smoke outlet of 6 is provided with a smoke thermometer 7 to control the air supply volume of the variable frequency cooling fan 5 until the temperature measured by the smoke thermometer 7 is between 800 and 820°C, and then locked. The air supply volume of the variable frequency air cooler 5;

The temperature control process is described with reference to FIG. 5. A smoke temperature measuring instrument 7 is provided at the smoke outlet 604 of the cyclone mixer, and its function is to control the air supply volume of the variable frequency cooling fan 5 by detecting the smoke temperature. , to ensure that the temperature of the mixed flue gas is maintained between 800 and 820 °C (±1 °C). The specific control methods are as follows:

The frequency is controlled by the PLC controller 12, and the frequency converter 11 is set to 15 frequency gears from 1 to 15; the temperature detected by the smoke thermometer 7, when the temperature is higher than 820°C, is increased by 5°C for every 5°C. , the PLC controller 12 will control the frequency converter 11 to increase the frequency by one gear, so that the air supply volume will gradually increase; if the temperature detected by the smoke thermometer 7 is lower than 800 ℃, the PLC controller 12 will Control the inverter 11 to reduce the frequency by one gear, so that the air supply volume is gradually reduced; when the temperature detected by the smoke temperature detector 7 is 800-820°C (±1°C), the PLC controller 12 will send out a signal to the inverter 11. When the frequency signal is locked, the frequency sent by the inverter 11 will no longer change, and the air supply volume of the variable frequency blower 5 will remain unchanged until the smoke temperature of the smoke thermometer 7 is higher than 820°C or lower than 800°C again. , and then adjust the temperature in the same way.

Studies have shown that the cyclone mixer 6 has a high dust removal efficiency for dust particles above 5-10 μm, and the highest dust removal efficiency is close to 90%, which makes up for the deficiencies of the gravity dust removal method in dust removal, and reduces the number of smoke pipes 802 in the hot air heat exchanger 8. mechanical wear. The dust particles removed by the cyclone mixer 6 will be discharged from the ash discharge port 605;

The flue gas usually contains some unburned charcoal, which has a high temperature and will not burn when it does not meet oxygen; when these unburned charcoal enters the hot air heat exchanger 8, it will accumulate in the flue gas pipe 802 , if oxygen is mixed into the flue gas pipe 802 , the charcoal will be burned for a second time, which may burn out the hot air heat exchanger 8 and cause great economic losses. While removing the dust particles in the flue gas, the cyclone mixer 6 can also remove these unburned chars, eliminate hidden dangers, and prevent them from entering the hot air heat exchanger 8 .

Claims (7)

1. The utility model provides a living beings hot-blast furnace system with steerable flue gas temperature of whirlwind blender which characterized in that includes:

a biomass hot blast stove unit;

the biomass hot blast stove unit comprises a first settling chamber (1), a second settling chamber (2), a smoke inlet thermometer (3), an air-smoke mixing chamber (4), a variable frequency air cooler (5), a cyclone mixer (6), a smoke outlet thermometer (7), a hot air heat exchanger (8) and a biomass burner (18);

the first settling chamber (1) is communicated with the second settling chamber (2), a smoke inlet thermometer (3) is installed at a smoke outlet of the second settling chamber (2), the second settling chamber (2) is communicated with an air-smoke mixing chamber (4), a variable-frequency air cooler (5) is installed in the air-smoke mixing chamber (4), the air-smoke mixing chamber (4) is communicated with a smoke inlet (601) of a cyclone mixer (6), the cyclone mixer (6) is provided with an ash discharge port (605), the ash discharge port faces vertically downwards, a smoke outlet (604) of the cyclone mixer (6) is communicated with a hot air heat exchanger (8), and a smoke outlet of the cyclone mixer (6) is provided with a smoke outlet thermometer (7).

2. The biomass hot blast stove system with the cyclone mixer capable of controlling the temperature of the flue gas according to claim 1, further comprising a console (9);

a PLC (programmable logic controller) (12) is arranged inside the console (9), and a data transmission port (15) is also arranged on the console (9);

the biomass hot blast stove unit is provided with a signal transmission port (17), and the signal transmission port (17) is connected with the data transmission port (15) through a data transmission line (16).

3. The biomass hot blast stove system with the cyclone mixer capable of controlling the temperature of the flue gas according to claim 1 or 2, wherein the cyclone mixer (6) is a cavity formed by a cylinder and a cone, and the cylinder and the cone are respectively marked as a cylindrical empty flue gas mixing bin (602) and a conical empty flue gas mixing bin (603); the smoke inlet (601) is arranged on the outer shell of the cylindrical side wall of the cylindrical empty smoke mixing bin, and the smoke outlet (604) is arranged on the end surface above the cylinder of the cylindrical empty smoke mixing bin; the ash discharge port (605) is a conical port of the conical empty tobacco mixing bin.

4. The biomass hot blast furnace system with the cyclone mixer capable of controlling the temperature of the flue gas as claimed in claim 1 or 2, wherein a heat exchanger smoke inlet (801) is arranged above the left side of the shell of the side wall of the hot blast heat exchanger (8); the smoke passing pipe (802) is arranged inside the hot air heat exchanger (8), and an upper pipe orifice of the smoke passing pipe (802) is connected with a smoke inlet (801) of the heat exchanger; a hot air outlet (805) is arranged above the right side of the side wall shell of the hot air heat exchanger (8); the cold air inlet (804) is arranged at the left lower part of the side wall shell of the hot air heat exchanger (8); a heat exchanger smoke outlet (803) is arranged below the right side of the shell of the side wall of the hot air heat exchanger (8) and is connected with a lower pipe opening of the smoke passing pipe (802).

5. The biomass hot blast stove system with the cyclone mixer capable of controlling the temperature of the flue gas according to the claim 1 or 2 is characterized in that an industrial display (10), a frequency converter (11), a control keyboard (13) and an emergency brake valve (14) are arranged on the console (9).

6. The biomass hot blast stove system with a cyclone mixer capable of controlling flue gas temperature according to claim 5, characterized in that the PLC controller (12) is used for receiving and sending all collected information and control instructions.

7. The biomass hot blast stove control system with automatic controllable flue gas temperature according to claim 6, characterized in that the emergency brake valve (14) is used for rapidly stopping all work of the biomass hot blast stove when the system has an uncontrollable fault.

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