Biomass coupling pulverized coal boiler combustion system and operation method thereof

Abstract

The invention discloses a biomass coupling pulverized coal boiler combustion system and an operation method thereof. The system comprises a biomass primary crushing unit, a biomass thermochemical treatment unit, a biomass grinding and pulverizing unit, a fire coal pulverizing unit, an air supply unit, a combustor, a boiler and a recirculation fan. According to the technical scheme provided by the invention, a biomass material is converted into biomass coke powder and combustible gas through graded and efficient pre-treatment processes such as crushing, thermochemical treatment and grinding of the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and powdering unit in sequence, and then the biomass coke powder and the combustible gas enter the combustor to be subjected to combustion reaction; the large-scale absorption difficulty caused by complex and changeable biomass sources, high impurity content, poor abradability and the like is overcome, large-scale, efficient and flexible biomass blending combustion of the boiler is achieved, and the boiler has the advantages of being large in disposal amount, wide in adaptability, high in compatibility, high in operation efficiency, good in environmental friendliness and the like.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of biomass-coupled power generation, and in particular to a biomass-coupled pulverized coal boiler combustion system and an operation method thereof. Background Art

[0002] Biomass resources are very abundant, and the rational use of biomass is of great significance for achieving the dual carbon goals as soon as possible. At present, the pilot work of biomass coupling power generation has received strong support, especially the agricultural and forestry biomass coupling project. Taking into account factors such as power generation efficiency, investment cost, and operation and maintenance, the direct coupling method is currently the main development direction of large-scale coal-fired coupled biomass power generation technology.

[0003] The main chemical components of agricultural and forestry biomass are lignin, cellulose and hemicellulose. They have low compressive strength, long fibers, low probability of collision and breakage between materials, and poor grindability. It is more effective to use shear force and grinding force to break biomass. Agricultural and forestry biomass usually requires multi-stage crushing to break into a suitable particle size range suitable for combustion in pulverized coal boilers. Among them, coarse crushing devices generally use low-speed pulverizers, medium crushing devices generally use medium-speed pulverizers, and fine crushing devices generally use high-speed pulverizers. The higher the speed of the pulverizer, the more serious the wear of the blade and the shorter the life. In addition, agricultural and forestry biomass crushing devices generally have problems such as low output, poor fuel adaptability, and high cost, especially fine and medium crushing pulverizers, which restrict the scale of disposal of agricultural and forestry biomass co-combustion. Summary of the invention

[0004] The embodiment of the present invention provides a biomass-coupled pulverized coal boiler combustion system and an operation method thereof to solve the problems of complex and changeable sources of biomass fuel, high impurity content, and poor grindability.

[0005] In a first aspect, an embodiment of the present invention provides a biomass coupled pulverized coal boiler combustion system, the system comprising: a biomass primary crushing unit, a biomass thermochemical treatment unit, a biomass grinding and pulverizing unit, a coal pulverizing unit, an air supply unit, a burner, a boiler and a recirculation fan; wherein,

[0006] The biomass primary crushing unit is used to crush the biomass material, and send the biomass crushed materials obtained by crushing into the biomass thermochemical treatment unit, and send the dust removal wind generated in the crushing process into the biomass grinding and powder making unit;

[0007] The biomass thermochemical treatment unit is used to perform thermochemical treatment on the biomass crushed material to obtain biomass char and combustible gas, and to feed the biomass char into the biomass grinding and milling unit, and to feed the combustible gas into the burner;

[0008] The biomass grinding and pulverizing unit is used to grind the biomass char material and feed the ground biomass char powder into the burner;

[0009] The coal pulverizing unit is used to grind the raw coal material and feed the ground coal powder into the burner;

[0010] The air supply unit is used to heat the outside air and then send it into the biomass thermochemical treatment unit and the burner;

[0011] The burner is used for the biomass coke powder, the coal powder and the combustible gas to perform a combustion reaction to drive the boiler to work;

[0012] The recirculation fan is used to send the flue gas exhausted when the boiler is working into the biomass thermochemical treatment unit and the biomass grinding and pulverizing unit.

[0013] Optionally, the biomass primary crushing unit includes: a biomass pulverizer, a cyclone separator, an electric air lock and a dust removal fan; wherein,

[0014] The biomass crusher is used to crush the biomass material, and the obtained biomass crushed material includes biomass coarse material and biomass fine material. The biomass coarse material is directly sent to the biomass thermochemical treatment unit, and the biomass fine material is sucked into the cyclone separator;

[0015] The cyclone separator is used to perform gas-solid separation on the sucked biomass fine material and air, and to send the collected biomass fine material into the electric air lock, and to send the discharged dust removal air into the biomass grinding and powdering unit through the dust removal fan;

[0016] The electric air lock is used to feed the biomass fine material into the biomass thermochemical treatment unit and isolate the gas exchange between the cyclone separator and the biomass thermochemical treatment unit.

[0017] Optionally, the biomass thermochemical treatment unit comprises: a flue gas header, an air header and a biomass thermochemical treatment furnace; wherein,

[0018] The flue gas header is used to collect the flue gas sent by the recirculation fan, and send the flue gas into the biomass thermochemical treatment furnace and the biomass grinding and powdering unit in multiple ways;

[0019] The air header is used to collect the heated air sent by the air supply unit and send the heated air into the biomass thermochemical treatment furnace;

[0020] The biomass thermochemical treatment furnace is used to perform thermochemical treatment on the biomass fragments, and to feed the obtained biomass char into the biomass grinding and pulverizing unit, and to feed the obtained combustible gas into the burner.

[0021] Optionally, the biomass thermochemical treatment furnace includes a furnace cavity, a chain, a first wind chamber, a second wind chamber, a third wind chamber and a fourth wind chamber; wherein,

[0022] The furnace cavity is used for the biomass fragments to undergo a thermochemical reaction;

[0023] The chain is arranged obliquely at the bottom of the furnace cavity, the first wind chamber, the second wind chamber, the third wind chamber and the fourth wind chamber are arranged sequentially below the chain, and the chain is used to pass the biomass crushed material through the first wind chamber, the second wind chamber, the third wind chamber and the fourth wind chamber in sequence to obtain the biomass char;

[0024] The biomass thermochemical processing unit further comprises: a first gas mixer and a second gas mixer;

[0025] The flue gas manifold is divided into five gas outlets, the first flue gas is directly sent to the first wind chamber, and is used to dry the biomass crushed materials at the chain position corresponding to the first wind chamber, the second flue gas is sent to the first gas mixer, the third flue gas is sent to the second gas mixer, the fourth flue gas is directly sent to the fourth wind chamber, and is used to perform the final carbonization process on the biomass crushed materials at the chain position corresponding to the fourth wind chamber, and the fifth flue gas is sent to the biomass grinding and milling unit;

[0026] The air manifold is divided into two gas outlets, the first heated air is sent to the first gas mixer, and the second heated air is sent to the second gas mixer; the first gas mixer is used to mix the second flue gas and the first heated air to obtain a first flue gas-air mixture and send it to the second wind chamber, so as to perform a primary carbonization process on the biomass fragments at the chain position corresponding to the second wind chamber; the second gas mixer is used to mix the third flue gas and the second heated air to obtain a second flue gas-air mixture and send it to the third wind chamber, so as to perform a secondary carbonization process on the biomass fragments at the chain position corresponding to the third wind chamber.

[0027] Optionally, the five outlet pipes of the flue gas manifold are respectively provided with a first regulating valve, a second regulating valve, a third regulating valve, a fourth regulating valve and a fifth regulating valve, which are respectively used to control the amount of flue gas discharged from the corresponding outlet pipes; the two outlet pipes of the air manifold are respectively provided with a sixth regulating valve and a seventh regulating valve, which are respectively used to control the amount of heated air discharged from the corresponding outlet pipes.

[0028] Optionally, the biomass grinding and milling unit comprises: a third gas mixer and a biomass mill; wherein,

[0029] The third gas mixer is used to collect the dust removal air sent from the biomass primary crushing unit and the flue gas sent from the flue gas header, and mix them to obtain a third flue gas-air mixture and send it to the biomass mill;

[0030] The biomass mill is used to grind the biomass char material, and the obtained biomass char powder is carried by the third flue gas-air mixture and sent to the burner.

[0031] Optionally, the burner includes: a pulverized coal burner, a coke burner, a gas burner and an overburnt air burner arranged vertically and hierarchically in sequence upward; wherein,

[0032] The pulverized coal burner is used to collect the pulverized coal sent by the coal-fired pulverizing unit and the heated air sent by the air supply unit for combustion reaction;

[0033] The coke powder burner is used to collect the biomass coke powder sent by the biomass grinding and pulverizing unit and the heated air sent by the air supply unit for combustion reaction;

[0034] The gas burner is used to collect the combustible gas sent by the biomass thermochemical treatment unit and the heated air sent by the air supply unit for combustion reaction;

[0035] The overburnt air burner is used to collect the heated air sent in by the air supply unit to perform combustion reaction on the unburned fuel sent in from below.

[0036] Optionally, the coal pulverizing unit includes: a first fan, an air heater and a coal mill; the air supply unit includes a second fan and an air preheater; wherein,

[0037] The first fan is used to suck in external air and pressurize it before sending it into the air heater;

[0038] The air heater is used to heat the pressurized air and then send it into the coal mill;

[0039] The coal mill is used to grind the raw coal material, and the obtained coal powder is carried by heated and pressurized air to the burner;

[0040] The second fan is used to suck in external air and pressurize it before sending it into the air preheater;

[0041] The air preheater is used to heat the pressurized air and then send it into the biomass thermochemical treatment unit and the burner.

[0042] In a second aspect, an embodiment of the present invention further provides an operation method of a biomass-coupled pulverized coal boiler combustion system, the method comprising:

[0043] Start the boiler, and sequentially put the air conveying unit and the coal pulverizing unit into operation, so that the pulverized coal and the heated air enter the burner for combustion reaction, and the heated air enters the biomass thermochemical treatment unit;

[0044] Putting into operation a recirculation fan to extract the flue gas exhausted by the boiler during operation and send it into the biomass thermochemical treatment unit and the biomass grinding and pulverizing unit;

[0045] The biomass grinding and milling unit, the biomass thermochemical treatment unit and the biomass primary crushing unit are put into operation in sequence, and biomass materials are added; the biomass materials are crushed in the biomass primary crushing unit to obtain biomass crushed materials, which are then sent to the biomass thermochemical treatment unit, and the dust removal wind generated during the crushing process is sent to the biomass grinding and milling unit; then the biomass crushed materials are thermochemically treated in the biomass thermochemical treatment unit, and the obtained biomass char is sent to the biomass grinding and milling unit, and the obtained combustible gas is sent to the burner for combustion reaction; and then the biomass char is ground in the biomass grinding and milling unit to obtain biomass char powder, which is then sent to the burner for combustion reaction.

[0046] Optionally, the method further includes:

[0047] Stop feeding the biomass material;

[0048] After waiting for a preset time, determining the temperature changes of the biomass primary crushing unit, the biomass thermochemical treatment unit, and the biomass grinding and milling unit;

[0049] If the temperature change is normal, the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and milling unit are shut down in sequence;

[0050] Shut down the recirculation fan;

[0051] If the boiler needs to be shut down, the coal pulverizing unit and the air supply unit are shut down in sequence.

[0052] The embodiment of the present invention provides a biomass coupled pulverized coal boiler combustion system, including a biomass primary crushing unit, a biomass thermochemical treatment unit, a biomass grinding and pulverizing unit, a coal-fired pulverizing unit, an air supply unit, a burner, a boiler and a recirculation fan. The biomass material is converted into biomass coke and combustible gas through the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and pulverizing unit in a graded and efficient pre-treatment process such as crushing, thermochemical treatment and grinding, and then enters the burner for combustion reaction, thereby overcoming the difficulties in large-scale consumption caused by the complex and changeable sources of biomass, high impurity content and poor grindability, and realizing a large proportion of biomass in the boiler with high efficiency and flexibility, which has the advantages of large disposal volume, wide adaptability, high compatibility, high operating efficiency and good environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A schematic diagram of the structure of a biomass-coupled pulverized coal boiler combustion system provided in Embodiment 1 of the present invention;

[0054] Figure 2 A schematic diagram of the structure of another biomass-coupled pulverized coal boiler combustion system provided in the first embodiment of the present invention;

[0055] Figure 3 A schematic diagram of the structure of a biomass thermochemical treatment unit provided in Example 1 of the present invention;

[0056] Figure 4 This is a flow chart of the operating method of the biomass coupled pulverized coal boiler combustion system provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0057] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0058] Embodiment 1

[0059] Figure 1 This is a schematic diagram of the structure of the biomass coupled pulverized coal boiler combustion system provided in the first embodiment of the present invention. This embodiment is applicable to the situation where the existing pulverized coal boiler equipment conditions are used to achieve large-scale processing of agricultural and forestry biomass. Figure 1As shown, the system includes: a biomass primary crushing unit 1, a biomass thermochemical treatment unit 2, a biomass grinding and pulverizing unit 3, a coal-fired pulverizing unit 4, an air supply unit 5, a burner 6, a boiler 7 and a recirculation fan 8; wherein the biomass primary crushing unit 1 is used to crush the biomass material, and send the biomass crushed material obtained by crushing into the biomass thermochemical treatment unit 2, and send the dust removal wind generated in the crushing process into the biomass grinding and pulverizing unit 3; the biomass thermochemical treatment unit 2 is used to perform thermochemical treatment on the biomass crushed material to obtain biomass char and combustible gas, and send the biomass char into the biomass grinding and pulverizing unit 3, and send the combustible gas into the The burner 6; the biomass grinding and pulverizing unit 3 is used to grind the biomass coke material, and feed the ground biomass coke powder into the burner 6; the coal-fired pulverizing unit 4 is used to grind the raw coal material, and feed the ground coal powder into the burner 6; the air supply unit 5 is used to heat the external air and then feed it into the biomass thermochemical treatment unit 2 and the burner 6; the burner 6 is used for the combustion reaction of the biomass coke powder, the coal powder and the combustible gas to drive the boiler 7 to work; the recirculation fan 8 is used to feed the flue gas exhausted when the boiler 7 is working into the biomass thermochemical treatment unit 2 and the biomass grinding and pulverizing unit 3.

[0060] Specifically, the biomass primary crushing unit 1 is connected to the biomass thermochemical treatment unit 2 and the biomass grinding and powdering unit 3 respectively. After the biomass material is put into the biomass primary crushing unit 1, the biomass crushed material is obtained after primary crushing and enters the biomass thermochemical treatment unit 2, and the dust removal wind generated during the primary crushing process enters the biomass grinding and powdering unit 3. Preferably, the biomass primary crushing unit 1 crushes the biomass material to within 10 cm. The biomass thermochemical treatment unit 2 is connected to the biomass grinding and powdering unit 3 and the burner 6 respectively. The biomass crushed material can be converted into biomass char and combustible gas through thermochemical treatments such as drying and carbonization in the biomass thermochemical treatment unit 2, wherein the biomass char is relatively coarse and enters the biomass grinding and powdering unit 3 for further grinding, and the combustible gas enters the burner 6 for combustion reaction. The biomass grinding and powdering unit 3 is connected to the burner 6, and the biomass char can be converted into biomass char powder after grinding, separation and other processes in the biomass grinding and powdering unit 3 and enters the burner 6 for combustion reaction. The coal-fired pulverizing unit 4 is connected to the burner 6. After the raw coal material is put into the coal-fired pulverizing unit 4, it can be dried, ground, separated, etc., and then converted into coal powder and enter the burner 6 for combustion reaction. The air supply unit 5 is respectively connected to the biomass thermochemical treatment unit 2 and the burner 6. After the external air is heated and pressurized in the air supply unit 5, a part of it enters the biomass thermochemical treatment unit 2 to provide a high-temperature heat source and oxygen for the thermochemical treatment process, and the other part enters the burner 6 to provide a high-temperature heat source and oxygen for the combustion reaction process. The burner 6 is connected to the boiler 7, and can be specifically installed on the boiler 7. The biomass coke powder, coal powder and combustible gas can be burned in the boiler 7 through the burner 6, thereby driving the boiler 7 to work. The recirculation fan 8 is respectively connected to the boiler 7, the biomass thermochemical treatment unit 2 and the biomass grinding and powder making unit 3. Part of the flue gas discharged from the tail of the boiler 7 is sucked into the recirculation fan 8, and then the recirculation fan 8 allows part of the flue gas to enter the biomass thermochemical treatment unit 2 to provide a high-temperature heat source for the thermochemical treatment process, and the other part of the flue gas enters the biomass grinding and powder making unit 3 to provide power for the biomass coke powder to enter the burner 6. Among them, the other part of the flue gas can directly enter the biomass grinding and powder making unit 3, or it can be indirectly transmitted to the biomass grinding and powder making unit 3 through the biomass thermochemical treatment unit 2. Preferably, the recirculation fan 8 can be designed with a pressure head of 2-6kPa and equipped with a variable frequency and anti-wear motor. The thermochemical treatment process can improve the energy density and grindability of biomass, and at the same time improve the microstructure of agricultural and forestry biomass. The existing pulverized coal boiler can provide high-temperature heat sources such as high-temperature flue gas (i.e., discharged from the tail of boiler 7) and high-temperature air (i.e., generated by air supply unit 5) for the thermochemical treatment of large-scale agricultural and forestry biomass, thereby making full use of the existing pulverized coal boiler equipment conditions to realize large-scale processing of agricultural and forestry biomass.

[0061] On the basis of the above technical solution, optional, such as Figure 2 As shown, the biomass primary crushing unit 1 includes: a biomass crusher 11, a cyclone separator 12, an electric air lock 13 and a dust removal fan 14; wherein the biomass crusher 11 is used to crush the biomass material, and the obtained biomass crushed material includes biomass coarse material and biomass fine material, the biomass coarse material is directly sent to the biomass thermochemical treatment unit 2, and the biomass fine material is sucked into the cyclone separator 12; the cyclone separator 12 is used to perform gas-solid separation on the sucked biomass fine material and air, and send the collected biomass fine material into the electric air lock 13, and send the discharged dust removal air into the biomass grinding and powdering unit 3 through the dust removal fan 14; the electric air lock 13 is used to send the biomass fine material into the biomass thermochemical treatment unit 2, and isolate the gas exchange between the cyclone separator 12 and the biomass thermochemical treatment unit 2.

[0062] Specifically, the biomass crusher 11 is connected to the cyclone separator 12 and the biomass thermochemical treatment unit 2 respectively, the cyclone separator 12 is connected to the electric air lock 13 and the dust removal fan 14 respectively, the electric air lock 13 is connected to the biomass thermochemical treatment unit 2, and the dust removal fan 14 is connected to the biomass grinding and powdering unit 3. Among them, the biomass crusher 11 can be specifically connected to the dust-containing air inlet in the middle of the cyclone separator 12, the cyclone separator 12 can be specifically connected to the dust removal fan 14 through the dust removal air exhaust port above, and the cyclone separator 12 can be specifically connected to the electric air lock 13 through the dust collection port below. The biomass material can be specifically put into the biomass crusher 11, and the biomass crusher 11 can include a discharge port at the bottom. The biomass coarse material obtained after crushing the biomass material can directly fall into the biomass thermochemical treatment unit 2 below by gravity through the discharge port, and the biomass coarse material can be centimeter-level crushed material. The two ends of the middle part of the biomass crusher 11 can respectively include an air inlet and a dust-containing air exhaust port, and the dust removal fan 14 works so that the crushing process of the biomass crusher 11 maintains negative pressure operation, so that the outside air is sucked in from the air inlet of the biomass crusher 11, and the dust-containing air is sucked out from the dust-containing air exhaust port of the biomass crusher 11 and sent to the cyclone separator 12. Then, a small amount of biomass fine material obtained after the biomass crusher 11 crushes the biomass material can be sucked into the cyclone separator 12 for gas-solid separation, and the separated biomass fine material can be sent to the electric air lock 13 from the dust collection port, and the separated dust removal air can be sent to the dust removal fan 14 from the dust removal air exhaust port, wherein the biomass fine material can be millimeter-level fragments or even smaller. Alternatively, the size of the biomass coarse material and the biomass fine material can be not limited, and the coarse and fine are just relative concepts of the two parts of the fragments, wherein the biomass coarse material is the part of the fragments that cannot be sucked into the cyclone separator 12, and the biomass fine material is the part of the fragments that can be sucked into the cyclone separator 12. Then the electric air lock 13 can send the collected biomass fines to the biomass thermochemical treatment unit 2, and the dust removal fan 14 can send the dust removal wind to the biomass grinding and powdering unit 3 after pressurization. Preferably, the dust removal fan 14 can be designed with a pressure head of 2-6 kPa and equipped with a variable frequency and anti-wear motor.

[0063] On the basis of the above technical solution, optional, such as Figure 2As shown, the biomass thermochemical treatment unit 2 includes: a flue gas header 21, an air header 22 and a biomass thermochemical treatment furnace 23; wherein the flue gas header 21 is used to collect the flue gas sent in by the recirculation fan 8, and send the flue gas into the biomass thermochemical treatment furnace 23 and the biomass grinding and powdering unit 3 in multiple ways; the air header 22 is used to collect the heated air sent in by the air supply unit 5, and send the heated air into the biomass thermochemical treatment furnace 23; the biomass thermochemical treatment furnace 23 is used to perform thermochemical treatment on the biomass fragments, and send the obtained biomass char into the biomass grinding and powdering unit 3, and send the obtained combustible gas into the burner 6.

[0064] Specifically, the flue gas header 21 is connected to the biomass thermochemical treatment furnace 23 and the biomass grinding and powdering unit 3, respectively, the air header 22 is connected to the biomass thermochemical treatment furnace 23, and the biomass thermochemical treatment furnace 23 is connected to the biomass grinding and powdering unit 3 and the burner 6, respectively. The recirculation fan 8 can be specifically connected to the flue gas header 21 to feed high-temperature flue gas into the flue gas header 21, and then the collected flue gas is divided into multiple paths and respectively fed into the biomass thermochemical treatment furnace 23 and the biomass grinding and powdering unit 3 through the flue gas header 21. Preferably, the flue gas temperature in the flue gas header 21 is 400-600°C. The air supply unit 5 can be specifically connected to the air header 22 to feed heated air into the air header 22, and then the collected heated air is fed into the biomass thermochemical treatment furnace 23 through the air header 22. Preferably, the heated air temperature in the air header 22 is 300-400°C. The biomass thermochemical treatment furnace 23 can be specifically connected to the biomass crusher 11 and the electric air lock 13, so as to obtain biomass crushed materials for thermochemical treatment to obtain biomass char and combustible gas, and then send the biomass char to the biomass grinding and powdering unit 3, and send the combustible gas to the burner 6.

[0065] Further optional, such as Figure 2 and Figure 3As shown, the biomass thermochemical treatment furnace 23 includes a furnace cavity 231, a chain 232, a first wind chamber 233, a second wind chamber 234, a third wind chamber 235 and a fourth wind chamber 236; wherein the furnace cavity 231 is used for the biomass fragments to undergo thermochemical reaction; the chain 232 is arranged obliquely at the bottom of the furnace cavity 231, and the first wind chamber 233, the second wind chamber 234, the third wind chamber 235 and the fourth wind chamber 236 are arranged in sequence below the chain 232. The chain 232 is used to pass the biomass fragments through the first wind chamber 233, the second wind chamber 234, the third wind chamber 235 and the fourth wind chamber 236 in sequence to obtain the biomass char; the biomass thermochemical treatment unit 2 also includes: a first gas mixer 24 and a second gas mixer 25; the flue gas manifold 21 is divided into five gas outlets, the first flue gas is directly sent to the first wind chamber 233, and is used to dry the biomass fragments at the chain position corresponding to the first wind chamber 233, and the third flue gas is directly sent to the first wind chamber 233. The second flue gas is sent to the first gas mixer 24, the third flue gas is sent to the second gas mixer 25, the fourth flue gas is directly sent to the fourth air chamber 236, and is used to perform the final carbonization process on the biomass fragments at the chain position corresponding to the fourth air chamber 236, and the fifth flue gas is sent to the biomass grinding and powdering unit 3; the air manifold 22 is divided into two gas outlets, the first heated air is sent to the first gas mixer 24, and the second heated air is sent to the second gas mixer 25; the first gas mixer 24 is used to mix the second flue gas and the first heated air to obtain a first flue gas-air mixture and send it to the second air chamber 234, so as to perform the primary carbonization process on the biomass fragments at the chain position corresponding to the second air chamber 234; the second gas mixer 25 is used to mix the third flue gas and the second heated air to obtain a second flue gas-air mixture and send it to the third air chamber 235, so as to perform the secondary carbonization process on the biomass fragments at the chain position corresponding to the third air chamber 235.

[0066] Specifically, the biomass crushed material can directly enter the furnace cavity 231 from the biomass primary crushing unit 1, and fall to the position of the chain 232 near one end of the first wind chamber 233. Through the inclined arrangement of the chain 232, the biomass crushed material entering the furnace cavity 231 can gradually pass through the first wind chamber 233, the second wind chamber 234, the third wind chamber 235 and the fourth wind chamber 236, and then fall to the position of the chain 232 near one end of the fourth wind chamber 236, that is, the lower position in the furnace cavity 231, and a discharge port can be set at this position to feed the biomass char obtained after the graded thermochemical treatment into the biomass grinding and pulverizing unit 3, and a gas outlet can also be set above the discharge port to feed the combustible gas obtained after the graded thermochemical treatment into the burner 6. Correspondingly, the flue gas manifold 21 is divided into five outlets, of which four outlets (i.e., the first to fourth outlets) correspond to the first wind chamber 233, the second wind chamber 234, the third wind chamber 235 and the fourth wind chamber 236 respectively to enter the biomass thermochemical treatment furnace 23 for thermochemical treatment of corresponding levels, and the other outlet enters the biomass grinding and powder making unit 3. The air manifold 22 is divided into two outlets, and the two heated airs correspond to the second wind chamber 234 and the third wind chamber 235 respectively to enter the biomass thermochemical treatment furnace 23 for thermochemical treatment of corresponding levels. Among them, the flue gas and heated air entering the same wind chamber can be mixed in advance by the corresponding gas mixer to obtain a relatively high-temperature flue gas-air mixture, and then sent to the corresponding wind chamber. Preferably, the first gas mixer 24 and the second gas mixer 25 use a Venturi structure.

[0067] Further optional, such as Figure 2 As shown, the five outlet pipes of the flue gas manifold 21 are respectively provided with a first regulating valve 91, a second regulating valve 92, a third regulating valve 93, a fourth regulating valve 94 and a fifth regulating valve 95, which are respectively used to control the amount of flue gas discharged from the corresponding outlet pipes; the two outlet pipes of the air manifold 22 are respectively provided with a sixth regulating valve 96 and a seventh regulating valve 97, which are respectively used to control the amount of heated air discharged from the corresponding outlet pipes. Thus, the amount of flue gas and the amount of heated air entering each wind chamber and the biomass grinding and powder making unit 3 are precisely controlled. Preferably, the oxygen concentration of the second wind chamber 234 is controlled at 10%-15%, and the oxygen concentration of the third wind chamber 235 is controlled at 10%-15%. By configuring the above four wind chambers and accurately adjusting and controlling the flow rate and oxygen concentration in the four wind chambers through each regulating valve, the thermochemical treatment requirements of biomass with different moisture content and volatile matter can be met, thereby improving the fuel adaptability of the biomass pre-treatment process. Preferably, the seven regulating valves are electric or pneumatic regulating valves.

[0068] On the basis of the above technical solution, optional, such as Figure 2As shown, the biomass grinding and powder making unit 3 includes: a third gas mixer 31 and a biomass mill 32; wherein, the third gas mixer 31 is used to collect the dust removal wind sent in by the biomass primary crushing unit 1 and the flue gas sent in by the flue gas manifold 21, and mix them to obtain a third flue gas-air mixture and send it to the biomass mill 32; the biomass mill 32 is used to grind the biomass char, and the obtained biomass char powder is carried by the third flue gas-air mixture to the burner 6.

[0069] Specifically, the third gas mixer 31 is connected to the biomass mill 32, and the third gas mixer 31 can be connected to the fifth outlet pipe of the flue gas manifold 21 and the dust removal fan 14 respectively, so as to obtain the fifth flue gas and the dust removal wind (relatively low temperature) for mixing, and obtain a relatively medium temperature third flue gas air mixture, and then send it to the biomass mill 32. The burner 6 can be connected to the biomass mill 32, and the biomass mill 32 can be connected to the furnace chamber 231 of the biomass thermochemical treatment furnace 23, so as to obtain biomass char for grinding, and then the obtained biomass char powder is sent to the burner 6 under the action of the third flue gas air mixture. Preferably, the third gas mixer 31 adopts a Venturi structure, and the biomass mill 32 adopts a power plant standby coal mill, and the oxygen concentration in the third gas mixer 31 is controlled to be no higher than 15%, and the temperature is controlled to be 150-250°C.

[0070] On the basis of the above technical solution, optional, such as Figure 2 As shown, the burner 6 includes: a pulverized coal burner 61, a coke burner 62, a gas burner 63 and a burnout air burner 64 which are arranged vertically and graded in sequence upward; wherein the pulverized coal burner 61 is used to collect the pulverized coal sent by the coal-fired pulverizing unit 4 and the heated air sent by the air supply unit 5 for combustion reaction; the coke burner 62 is used to collect the biomass coke sent by the biomass grinding and pulverizing unit 3 and the heated air sent by the air supply unit 5 for combustion reaction; the gas burner 63 is used to collect the combustible gas sent by the biomass thermochemical treatment unit 2 and the heated air sent by the air supply unit 5 for combustion reaction; the burnout air burner 64 is used to collect the heated air sent by the air supply unit 5 to carry out combustion reaction on the unburned fuel sent from below.

[0071] Specifically, the pulverized coal burner 61 can be arranged in the lower part of the main combustion area of ​​the boiler 7, the coke powder burner 62 can be arranged in the middle part of the main combustion area of ​​the boiler 7, the gas burner 63 can be arranged in the upper part of the main combustion area of ​​the boiler 7, and the overburnt air burner 64 can be arranged at a distance above the main combustion area of ​​the boiler 7. The coal-fired pulverizing unit 4 can be specifically connected to the pulverized coal burner 61 to feed pulverized coal into the pulverized coal burner 61, the biomass grinding and pulverizing unit 3 can be specifically connected to the coke powder burner 62 to feed biomass coke into the coke powder burner 62, and the biomass thermochemical treatment unit 2 can be specifically connected to the gas burner 63 to feed combustible gas into the gas burner 63. Further, the gas burner 63 can be specifically connected to the furnace chamber 231 of the biomass thermochemical treatment furnace 23, and the coke powder burner 62 can be specifically connected to the biomass mill 32. Thus, fuel stratified combustion is achieved, that is, coal powder, biomass coke powder generated after biomass pre-treatment, and combustible gas are fed into the boiler 7 in layers for combustion, the easy ignition property of biomass coke powder can improve the combustion performance in the furnace, and combustible gas as a reburning fuel can reduce NOx in the furnace, thereby improving the efficiency of the boiler 7 and reducing NOx emissions. Preferably, the combustible gas flow rate at the outlet of the gas burner 63 is not less than 30 meters per second.

[0072] On the basis of the above technical solution, optional, such as Figure 2 As shown, the coal-fired pulverizing unit 4 includes: a first fan 41, an air heater 42 and a coal mill 43; the air supply unit 5 includes a second fan 51 and an air preheater 52; wherein, the first fan 41 is used to inhale external air and pressurize it before sending it into the air heater 42; the air heater 42 is used to heat the pressurized air and then send it into the coal mill 43; the coal mill 43 is used to grind the raw coal material, and the obtained coal powder is carried by the heated and pressurized air into the burner 6; the second fan 51 is used to inhale external air and pressurize it before sending it into the air preheater 52; the air preheater 52 is used to heat the pressurized air and then send it into the biomass thermochemical treatment unit 2 and the burner 6.

[0073] Specifically, the first fan 41 is connected to the air heater 42, and can draw air from the atmosphere and pressurize it into high-pressure air to enter the air heater 42. The air heater 42 is connected to the coal mill 43, and the high-pressure air is heated to high-temperature and high-pressure air and enters the coal mill 43, so that the coal powder is brought into the burner 6 through the high-temperature and high-pressure air for combustion reaction. The burner 6 can be specifically connected to the coal mill 43, and further, the coal mill 43 can be specifically connected to the coal powder burner 61, so that the ground coal powder is sent to the coal powder burner 61. Preferably, the air heater 42 uses a plate heat exchanger. The second fan 51 is connected to the air preheater 52, and can draw air from the atmosphere and pressurize it into medium-pressure air to enter the air preheater 52. The biomass thermochemical treatment unit 2 and the burner 6 can be specifically connected to the air preheater 52. Further, the air preheater 52 can be specifically connected to the pulverized coal burner 61, the coke burner 62, the gas burner 63, the burnout air burner 64 and the air header 22, respectively. The medium-pressure air is heated to high-temperature medium-pressure air and enters the pulverized coal burner 61, the coke burner 62, the gas burner 63, the burnout air burner 64 and the air header 22 respectively. Preferably, the air preheater 52 uses a rotary air preheater. Among them, the heated and pressurized air discharged by the air heater 42 can refer to the actual application to achieve the purpose of driving the pulverized coal into the burner 6 and is suitable for the raw coal material processing process to set the temperature and pressure, and the heated and pressurized air discharged by the air preheater 52 can refer to the actual application to be able to send the air itself to a designated location and is suitable for the thermochemical treatment process and the combustion reaction process to set the temperature and pressure.

[0074] The biomass coupled pulverized coal boiler combustion system provided in the embodiment of the present invention includes a biomass primary crushing unit, a biomass thermochemical treatment unit, a biomass grinding and pulverizing unit, a coal-fired pulverizing unit, an air supply unit, a burner, a boiler and a recirculation fan. The biomass material is converted into biomass coke powder and combustible gas through the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and pulverizing unit in a graded and efficient pre-treatment process such as crushing, thermochemical treatment and grinding, and then enters the burner for combustion reaction, thereby overcoming the difficulties in large-scale consumption caused by the complex and changeable sources of biomass, high impurity content and poor grindability, and realizing the large-scale, efficient and flexible mixing of biomass in the boiler, with the advantages of large disposal volume, wide adaptability, high compatibility, high operating efficiency and good environmental protection. The system can specifically adapt to large-scale pulverized coal boilers above 300MW, including counter-burning boilers and tangentially burning boilers, and has high compatibility with existing boiler combustion systems, pulverizing and grinding systems and other equipment, and the overall system adaptability is good.

[0075] Embodiment 2

[0076] Figure 4This is a flow chart of the operation method of the biomass coupled pulverized coal boiler combustion system provided in Example 1 of the present invention. This method can be applied to the biomass coupled pulverized coal boiler combustion system provided in the embodiment of the present invention, and can be used to achieve large-scale processing of agricultural and forestry biomass using existing pulverized coal boiler equipment conditions.

[0077] like Figure 4 As shown, the specific steps include:

[0078] S41, start the boiler, and sequentially put the air conveying unit and the coal pulverizing unit into operation, so that the pulverized coal and the heated air enter the burner for combustion reaction, and the heated air enters the biomass thermochemical treatment unit.

[0079] S42, putting into operation a recirculation fan to extract the flue gas exhausted when the boiler is working and send it into the biomass thermochemical treatment unit and the biomass grinding and pulverizing unit.

[0080] S43, sequentially put into operation the biomass grinding and milling unit, the biomass thermochemical treatment unit and the biomass primary crushing unit, and put in biomass materials; so that the biomass materials are crushed in the biomass primary crushing unit to obtain biomass crushed materials, which are sent to the biomass thermochemical treatment unit, and the dust removal wind generated during the crushing process is sent to the biomass grinding and milling unit; then the biomass crushed materials are thermochemically treated in the biomass thermochemical treatment unit, and the obtained biomass char is sent to the biomass grinding and milling unit, and the obtained combustible gas is sent to the burner for combustion reaction; and then the biomass char is ground in the biomass grinding and milling unit to obtain biomass char powder, which is sent to the burner for combustion reaction.

[0081] Specifically, the operation method may include a startup method, such as S41-S43 mentioned above. First, the pulverized coal processing and combustion part can be put into operation, and at the same time, a part of the heated air discharged from the air supply unit can be allowed to enter the biomass thermochemical treatment unit for standby, and specifically can enter the air manifold. Then, the flue gas discharged from the boiler can be extracted by the recirculation fan as a heat source for the biomass-related treatment process, and then the biomass processing and combustion part can be put into operation to ensure the biomass pre-treatment effect. The flue gas extracted by the recirculation fan can be specifically sent to the flue gas manifold for the thermochemical treatment process, and can be sent to the biomass grinding and powder making unit through the flue gas manifold for the grinding process. Specifically, after the biomass grinding and powder making unit is put into operation, the regulating valve on the flue gas manifold outlet pipe corresponding to the grinding process can be opened to allow the flue gas to enter the biomass grinding and powder making unit. Then, after the biomass thermochemical treatment unit is put into operation, the regulating valve on the flue gas manifold outlet pipe corresponding to the thermochemical treatment process and the regulating valve on the air manifold outlet pipe can be opened, and each regulating valve can be adjusted so that the flow rates in the first wind chamber, the second wind chamber, the third wind chamber and the fourth wind chamber are basically the same, and the oxygen concentration in the second wind chamber and the third wind chamber is 10%-15%. Subsequently, the biomass primary crushing unit can be put into operation so that the dust removal wind enters the biomass grinding and powder making unit. At this time, the regulating valve on the flue gas manifold outlet pipe corresponding to the grinding process can be adjusted again so that the oxygen concentration of the gas in the third gas mixer is not higher than 15%. Finally, the biomass material is put into the burner to undergo the processes of crushing, thermochemical treatment and grinding in the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and powder making unit in sequence. Among them, the relevant description can refer to the content of the above embodiment, which will not be repeated here.

[0082] On the basis of the above technical solution, optionally, the method also includes: stopping the input of the biomass material; after waiting for a preset period of time, determining the temperature changes of the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and powder making unit; if the temperature changes are normal, shutting down the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and powder making unit in sequence; shutting down the recycling fan; if it is necessary to exit the boiler, shutting down the coal-fired powder making unit and the air supply unit in sequence.

[0083] Specifically, the operation method may also include an exit method. After stopping the input of biomass materials, you can wait for 30 minutes to observe the temperature changes of the biomass primary crushing unit, the biomass thermochemical treatment unit, and the biomass grinding and pulverizing unit. If there is no temperature abnormality, the three units can be shut down in turn. If there is an abnormality, you can wait for a while, or manually take relevant measures. Then you can first close all the regulating valves, stop the air supply, and then shut down the recirculation fan. At this time, the biomass processing and combustion part will be shut down. Then you can keep the pulverized coal processing and combustion part in operation. If you need to exit the boiler, then shut down the coal-fired pulverizing unit and the air supply unit in turn.

[0084] The operation method of the biomass-coupled pulverized coal boiler combustion system provided in the embodiment of the present invention converts the biomass material into biomass coke powder and combustible gas by sequentially passing the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and milling unit through the graded and efficient pre-treatment processes of crushing, thermochemical treatment and grinding, and then enters the burner for combustion reaction, thereby overcoming the difficulties in large-scale consumption caused by the complex and changeable sources of biomass, high impurity content and poor grindability, and realizing the large-scale, efficient and flexible mixing of biomass in the boiler, which has the advantages of large disposal volume, wide adaptability, high compatibility, high operating efficiency and good environmental protection. At the same time, through a reasonable order of commissioning, the effect of biomass pre-treatment is further guaranteed.

[0085] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A biomass coupled pulverized coal boiler combustion system, characterized in that: include: Biomass primary crushing unit, biomass thermochemical treatment unit, biomass grinding and pulverizing unit, coal-fired pulverizing unit, air supply unit, burner, boiler and recirculation fan; among which, The biomass primary crushing unit is used to crush the biomass material, and send the biomass crushed materials obtained by crushing into the biomass thermochemical treatment unit, and send the dust removal wind generated in the crushing process into the biomass grinding and powder making unit; The biomass thermochemical treatment unit is used to perform thermochemical treatment on the biomass crushed material to obtain biomass char and combustible gas, and to feed the biomass char into the biomass grinding and milling unit, and to feed the combustible gas into the burner; The biomass grinding and pulverizing unit is used to grind the biomass char material and feed the ground biomass char powder into the burner; The coal pulverizing unit is used to grind the raw coal material and feed the ground coal powder into the burner; The air supply unit is used to heat the outside air and then send it into the biomass thermochemical treatment unit and the burner; The burner is used for the biomass coke powder, the coal powder and the combustible gas to perform a combustion reaction to drive the boiler to work; The recirculation fan is used to send the flue gas exhausted when the boiler is working into the biomass thermochemical treatment unit and the biomass grinding and pulverizing unit.

2. The biomass coupled pulverized coal boiler combustion system according to claim 1 is characterized in that: The biomass primary crushing unit includes: a biomass pulverizer, a cyclone separator, an electric air lock and a dust removal fan; wherein, The biomass crusher is used to crush the biomass material, and the obtained biomass crushed material includes biomass coarse material and biomass fine material. The biomass coarse material is directly sent to the biomass thermochemical treatment unit, and the biomass fine material is sucked into the cyclone separator; The cyclone separator is used to perform gas-solid separation on the sucked biomass fine material and air, and to send the collected biomass fine material into the electric air lock, and to send the discharged dust removal air into the biomass grinding and powdering unit through the dust removal fan; The electric air lock is used to feed the biomass fine material into the biomass thermochemical treatment unit and isolate the gas exchange between the cyclone separator and the biomass thermochemical treatment unit.

3. The biomass coupled pulverized coal boiler combustion system according to claim 1 is characterized in that: The biomass thermochemical treatment unit comprises: a flue gas header, an air header and a biomass thermochemical treatment furnace; wherein, The flue gas header is used to collect the flue gas sent by the recirculation fan, and send the flue gas into the biomass thermochemical treatment furnace and the biomass grinding and powdering unit in multiple ways; The air header is used to collect the heated air sent by the air supply unit and send the heated air into the biomass thermochemical treatment furnace; The biomass thermochemical treatment furnace is used to perform thermochemical treatment on the biomass fragments, and to feed the obtained biomass char into the biomass grinding and pulverizing unit, and to feed the obtained combustible gas into the burner.

4. The biomass coupled pulverized coal boiler combustion system according to claim 3 is characterized in that: The biomass thermochemical treatment furnace comprises a furnace cavity, a chain, a first wind chamber, a second wind chamber, a third wind chamber and a fourth wind chamber; wherein, The furnace cavity is used for the biomass fragments to undergo a thermochemical reaction; The chain is arranged obliquely at the bottom of the furnace cavity, the first wind chamber, the second wind chamber, the third wind chamber and the fourth wind chamber are arranged sequentially below the chain, and the chain is used to pass the biomass crushed material through the first wind chamber, the second wind chamber, the third wind chamber and the fourth wind chamber in sequence to obtain the biomass char; The biomass thermochemical processing unit further comprises: a first gas mixer and a second gas mixer; The flue gas manifold is divided into five gas outlets, the first flue gas is directly sent to the first wind chamber, and is used to dry the biomass crushed materials at the chain position corresponding to the first wind chamber, the second flue gas is sent to the first gas mixer, the third flue gas is sent to the second gas mixer, the fourth flue gas is directly sent to the fourth wind chamber, and is used to perform the final carbonization process on the biomass crushed materials at the chain position corresponding to the fourth wind chamber, and the fifth flue gas is sent to the biomass grinding and milling unit; The air manifold is divided into two gas outlets, the first heated air is sent to the first gas mixer, and the second heated air is sent to the second gas mixer; the first gas mixer is used to mix the second flue gas and the first heated air to obtain a first flue gas-air mixture and send it to the second wind chamber, so as to perform a primary carbonization process on the biomass fragments at the chain position corresponding to the second wind chamber; the second gas mixer is used to mix the third flue gas and the second heated air to obtain a second flue gas-air mixture and send it to the third wind chamber, so as to perform a secondary carbonization process on the biomass fragments at the chain position corresponding to the third wind chamber.

5. The biomass coupled pulverized coal boiler combustion system according to claim 4 is characterized in that: The five outlet pipes of the flue gas manifold are respectively provided with a first regulating valve, a second regulating valve, a third regulating valve, a fourth regulating valve and a fifth regulating valve, which are respectively used to control the amount of flue gas discharged from the corresponding outlet pipes; the two outlet pipes of the air manifold are respectively provided with a sixth regulating valve and a seventh regulating valve, which are respectively used to control the amount of heated air discharged from the corresponding outlet pipes.

6. The biomass coupled pulverized coal boiler combustion system according to claim 3, characterized in that: The biomass grinding and powder making unit comprises: a third gas mixer and a biomass mill; wherein, The third gas mixer is used to collect the dust removal air sent from the biomass primary crushing unit and the flue gas sent from the flue gas header, and mix them to obtain a third flue gas-air mixture and send it to the biomass mill; The biomass mill is used to grind the biomass char material, and the obtained biomass char powder is carried by the third flue gas-air mixture and sent to the burner.

7. The biomass coupled pulverized coal boiler combustion system according to claim 1, characterized in that: The burner comprises: a pulverized coal burner, a coke burner, a gas burner and an overburnt air burner which are arranged vertically and hierarchically in sequence upward; wherein, The pulverized coal burner is used to collect the pulverized coal sent by the coal-fired pulverizing unit and the heated air sent by the air supply unit for combustion reaction; The coke powder burner is used to collect the biomass coke powder sent by the biomass grinding and pulverizing unit and the heated air sent by the air supply unit for combustion reaction; The gas burner is used to collect the combustible gas sent by the biomass thermochemical treatment unit and the heated air sent by the air supply unit for combustion reaction; The overburnt air burner is used to collect the heated air sent in by the air supply unit to perform combustion reaction on the unburned fuel sent in from below.

8. The biomass coupled pulverized coal boiler combustion system according to claim 1, characterized in that: The coal pulverizing unit comprises: a first fan, an air heater and a coal mill; the air supply unit comprises a second fan and an air preheater; wherein, The first fan is used to suck in external air and pressurize it before sending it into the air heater; The air heater is used to heat the pressurized air and then send it into the coal mill; The coal mill is used to grind the raw coal material, and the obtained coal powder is carried by heated and pressurized air to the burner; The second fan is used to suck in external air and pressurize it before sending it into the air preheater; The air preheater is used to heat the pressurized air and then send it into the biomass thermochemical treatment unit and the burner.

9. A method for operating a biomass-coupled pulverized coal boiler combustion system, characterized in that: include: Start the boiler, and sequentially put the air conveying unit and the coal pulverizing unit into operation, so that the pulverized coal and the heated air enter the burner for combustion reaction, and the heated air enters the biomass thermochemical treatment unit; Putting into operation a recirculation fan to extract the flue gas exhausted by the boiler during operation and send it into the biomass thermochemical treatment unit and the biomass grinding and pulverizing unit; The biomass grinding and milling unit, the biomass thermochemical treatment unit and the biomass primary crushing unit are put into operation in sequence, and biomass materials are put into the unit; the biomass materials are crushed in the biomass primary crushing unit to obtain biomass crushed materials which are sent to the biomass thermochemical treatment unit, and the dust removal wind generated during the crushing process is sent to the biomass grinding and milling unit; Then, the biomass fragments are subjected to thermochemical treatment in the biomass thermochemical treatment unit, and the obtained biomass char is sent to the biomass grinding and pulverizing unit, and the obtained combustible gas is sent to the burner for combustion reaction; The biomass char is then ground in the biomass grinding and powdering unit to obtain biomass char powder which is then fed into the burner for combustion reaction.

10. The operation method of the biomass coupled pulverized coal boiler combustion system according to claim 9, characterized in that: The method further comprises: Stop feeding the biomass material; After waiting for a preset time, determining the temperature changes of the biomass primary crushing unit, the biomass thermochemical treatment unit, and the biomass grinding and milling unit; If the temperature change is normal, the biomass primary crushing unit, the biomass thermochemical treatment unit and the biomass grinding and milling unit are shut down in sequence; Deactivating the recirculation fan; If the boiler needs to be shut down, the coal pulverizing unit and the air supply unit are shut down in sequence.

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