A two-stage series deep peak regulation circulating fluidized bed boiler

Abstract

The present invention provides a two-stage series deep peak-shaving circulating fluidized bed boiler, which relates to the field of circulating fluidized bed boilers, including: a main furnace system, including: a main furnace, a main air distribution plate arranged in the main furnace, and a main furnace water-cooled air chamber arranged below the main air distribution plate; an auxiliary furnace system, including: an auxiliary furnace, an auxiliary air distribution plate arranged in the auxiliary furnace, an auxiliary furnace water-cooled air chamber arranged below the auxiliary air distribution plate, and an auxiliary furnace cyclone separator connected to the auxiliary furnace; the main air distribution plate and the auxiliary air distribution plate are both used to carry bed materials, the main furnace and the auxiliary furnace are connected, and the bed materials in the main furnace can be transported to the auxiliary furnace; the flue gas outlet of the auxiliary furnace cyclone separator is connected to the main furnace water-cooled air chamber, and the high-temperature flue gas generated by the combustion of the bed materials in the auxiliary furnace can be discharged into the main furnace water-cooled air chamber through the auxiliary furnace cyclone separator. The present invention uses the auxiliary furnace to provide heat for the main furnace when the fire is pressed, thereby extending the fire pressing time of the main furnace.

Description

Technical Field

[0001] The invention relates to the technical field of circulating fluidized bed boilers, in particular to a two-stage series-connected deep peak-shaving circulating fluidized bed boiler. Background Art

[0002] With the rapid development of new energy in recent years, the proportion of new energy installed capacity and power generation has increased significantly, but the inherent randomness and volatility of new energy power have brought great difficulties to the consumption of new energy and grid dispatching. In order to solve the difficulties in the consumption of new energy and grid dispatching, it is necessary to further improve the peak-shaving capacity of conventional units such as thermal power units in the grid.

[0003] As a common coal-fired power generation unit, circulating fluidized bed units have been vigorously developed due to their good fuel adaptability and low pollutant generation. By improving the peak-shaving capacity of circulating fluidized bed units, the grid's new energy consumption capacity can be effectively improved and the grid dispatching pressure can be alleviated.

[0004] In the prior art, since the circulating fluidized bed unit has a strong heat storage capacity, the heat storage of the circulating fluidized bed unit can be used to achieve the peak regulation of the circulating fluidized bed unit; however, after the circulating fluidized bed unit is compressed, there is no effective heat supplement, resulting in low steam parameters and short compression time, which cannot meet the scheduling requirements for the compression time.

[0005] Therefore, there is an urgent need for a device that can effectively improve the steam parameters during the ignition of a circulating fluidized bed and extend the ignition time. Summary of the invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the problem in the prior art that the ignition time of the circulating fluidized bed is short and cannot meet the scheduling requirements for the ignition time. A two-stage series deep peak-shaving circulating fluidized bed boiler is provided, which consists of a main furnace system and an auxiliary furnace system. The auxiliary furnace provides high-temperature flue gas to the main furnace during the ignition peak-shaving of the main furnace and the ignition start-up of the main furnace. On the one hand, it heats the bed material, which can increase the heat exchange of the water-cooled wall of the main furnace and generate more steam. On the other hand, it can increase the heat exchange of the rear heating surface, increase the steam superheat, and meet the requirements of steam volume and steam quality during low-load operation.

[0007] In order to solve the above technical problems, the present invention provides a two-stage series deep peak-shaving circulating fluidized bed boiler, comprising:

[0008] The main furnace system comprises: a main furnace, a main air distribution plate arranged in the main furnace, and a main furnace water-cooling air chamber arranged below the main air distribution plate;

[0009] An auxiliary furnace system, comprising: an auxiliary furnace, an auxiliary air distribution plate arranged in the auxiliary furnace, an auxiliary furnace water-cooled air chamber arranged below the auxiliary air distribution plate, and an auxiliary furnace cyclone separator communicated with the auxiliary furnace;

[0010] Wherein: the main air distribution plate and the auxiliary air distribution plate are both used to carry bed materials, the main furnace and the auxiliary furnace are connected, and the bed materials in the main furnace can be transported to the auxiliary furnace;

[0011] The flue gas outlet of the auxiliary furnace cyclone separator is connected to the main furnace water-cooling air chamber, and the high-temperature flue gas generated by the combustion of bed materials in the auxiliary furnace can be discharged into the main furnace water-cooling air chamber through the auxiliary furnace cyclone separator.

[0012] In one embodiment of the present invention, a conveying connecting pipe is arranged between the main furnace and the auxiliary furnace, and both ends of the conveying connecting pipe are respectively connected to the main furnace and the auxiliary furnace, and both ends of the conveying connecting pipe are respectively arranged above the main air distribution plate and the auxiliary air distribution plate.

[0013] In one embodiment of the present invention, one end of the transport connecting pipe communicating with the main furnace is higher than one end of the transport connecting pipe communicating with the auxiliary furnace.

[0014] In one embodiment of the present invention, a control valve is further provided on the delivery connecting pipe.

[0015] In one embodiment of the present invention, the auxiliary furnace cyclone separator and the main furnace water-cooled air chamber are connected via a heat-insulating connecting pipe.

[0016] In one embodiment of the present invention, the insulating connecting pipe has an air inlet connected to the auxiliary furnace cyclone separator and multiple air outlets connected to the main furnace water-cooled air chamber, and high-temperature flue gas can be discharged into the main furnace water-cooled air chamber from the air outlet.

[0017] In one embodiment of the present invention, the auxiliary furnace system further includes: an auxiliary fluidizing air duct connected to the auxiliary furnace water-cooling air chamber and a fluidizing air valve arranged on the auxiliary fluidizing air duct.

[0018] In one embodiment of the present invention, the auxiliary fluidizing air duct is communicated with an independent fluidizing air fan or a mainstream fluidizing air system.

[0019] In one embodiment of the present invention, the auxiliary furnace system further includes: an auxiliary coal feeder connected to the auxiliary furnace, and the auxiliary coal feeder continuously transports bed material into the auxiliary furnace.

[0020] In one embodiment of the present invention, the inner walls of the main furnace and the auxiliary furnace are cast with a refractory layer, and a water cooling pipe is buried in the refractory layer.

[0021] The above technical solution of the present invention has the following advantages compared with the prior art:

[0022] The two-stage series deep peak-shaving circulating fluidized bed boiler of the present invention is provided with a flue gas outlet of the auxiliary furnace cyclone separator connected to the main furnace water-cooling air chamber, so that the high-temperature flue gas generated by the combustion of the bed material in the auxiliary furnace can be discharged into the main furnace water-cooling air chamber through the auxiliary furnace cyclone separator;

[0023] 1. The auxiliary furnace can provide heat for the main furnace during the fire suppression, generate more qualified steam, and extend the fire suppression time of the main furnace;

[0024] 2. After the flue gas from the auxiliary furnace enters the tail flue of the main furnace, it can increase the heat exchange of the heating surface of the tail flue and increase the steam temperature;

[0025] 3. After the auxiliary flue gas enters the main furnace, the flue gas in the furnace changes from a stagnant state to a flowing state, reducing the accumulation of combustible gas in the furnace and reducing the risk of fire and explosion after the main furnace is ignited;

[0026] 4. When high-temperature flue gas enters the water-cooled air chamber of the main furnace, the temperature of the primary air entering the main furnace can be increased, so that the machine can be started at a lower bed temperature after ignition.

[0027] 5. When high-temperature flue gas enters the water-cooled air chamber of the main furnace, the bed temperature after fire suppression becomes more uniform along the vertical direction, which can greatly utilize the heat storage of the bed material.

[0028] The present invention also arranges the main furnace and the auxiliary furnace to be connected, so that the bed material in the main furnace can be transported to the auxiliary furnace, and the auxiliary furnace is started by using the bed material in the main furnace, thereby realizing the secondary application of the bed material and reducing the amount of bed material used. In addition, the hot bed material in the main furnace is directly used to reduce the energy consumed in heating the bed material. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0030] Figure 1 It is a structural schematic diagram of a two-stage series-connected deep peak-shaving circulating fluidized bed boiler of the present invention.

[0031] Explanation of the reference numerals in the drawings in the specification: 1. Main furnace; 2. Auxiliary furnace; 3. Main air distribution plate; 4. Auxiliary air distribution plate; 5. Transport connecting pipe; 6. Control valve; 7. Auxiliary furnace cyclone separator; 8. Flue gas outlet; 9. Insulation connecting pipe; 10. Main furnace water-cooled air chamber; 11. Auxiliary fluidizing air duct; 12. Fluidizing air valve; 13. Auxiliary coal feeder. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0033] Reference Figure 1 As shown, the present invention discloses a two-stage series deep peak-shaving circulating fluidized bed boiler, comprising: a main furnace system and an auxiliary furnace system, wherein: the main furnace system, as a coal-fired power generation unit, can process coal efficiently and with low pollution, and through the peak-shaving capability of the main furnace system, it can effectively improve the new energy absorption capacity of the power grid and alleviate the scheduling pressure of the power grid. In this embodiment, the auxiliary furnace system is arranged to be used in conjunction with the main furnace system during the peak-shaving process.

[0034] Specifically, the main furnace system includes: a main furnace 1, a main air distribution plate 3 arranged in the main furnace 1, and a main furnace water-cooling air chamber 10 arranged below the main air distribution plate 3; the auxiliary furnace system includes: an auxiliary furnace 2, an auxiliary air distribution plate 4 arranged in the auxiliary furnace 2, an auxiliary furnace water-cooling air chamber arranged below the auxiliary air distribution plate 4, and an auxiliary furnace cyclone separator 7 connected to the auxiliary furnace 2;

[0035] In this embodiment, the flue gas outlet 8 of the auxiliary furnace cyclone separator 7 is connected to the main furnace water-cooled air chamber 10, and the high-temperature flue gas generated by the combustion of the bed material in the auxiliary furnace 2 can be discharged into the main furnace water-cooled air chamber 10 through the auxiliary furnace cyclone separator 7. The auxiliary furnace 2 can provide heat for the main furnace 1 during ignition, generate more qualified steam, and extend the ignition time of the main furnace 1. In addition, after the flue gas from the auxiliary furnace 2 enters the tail flue of the main furnace 1, the heat exchange of the heating surface of the tail flue can be increased, thereby increasing the steam temperature.

[0036] Specifically, when the auxiliary flue gas enters the main furnace 1, the flue gas in the furnace changes from a stagnant state to a flowing state, which can reduce the accumulation of combustible gas in the furnace and reduce the risk of fire and explosion after the main furnace 1 is ignited.

[0037] Specifically, when high-temperature flue gas enters from the water-cooled air chamber 10 of the main furnace, the temperature of the primary air entering the main furnace 1 can be increased, so that the furnace can be started at a lower bed temperature after the fire is suppressed;

[0038] Specifically, when high-temperature flue gas enters the water-cooled air chamber 10 of the main furnace, the bed temperature after quenching is made more uniform along the vertical direction, and the heat storage of the bed material can be greatly utilized.

[0039] In the actual design, in order to pass the high-temperature flue gas from the auxiliary furnace cyclone separator 7 into the main furnace water-cooled air chamber 10, the auxiliary furnace cyclone separator 7 and the main furnace water-cooled air chamber 10 are connected through an insulating connecting pipe 9, one end of the insulating connecting pipe 9 is connected to the flue gas outlet 8 of the auxiliary furnace cyclone separator 7, and the other end of the insulating connecting pipe 9 is connected to the main furnace water-cooled air chamber 10. The insulating connecting pipe 9 can have a certain insulation effect and can prevent the heat loss of the high-temperature flue gas during transportation.

[0040] Reference Figure 1 As shown, in the present embodiment, the insulating connecting pipe 9 is provided with only one air inlet and one air outlet, and the high-temperature flue gas can enter the main furnace water-cooled air chamber 10 only from one position; in actual use, the insulating connecting pipe 9 can be improved, and the insulating connecting pipe 9 is provided with an air inlet connected to the auxiliary furnace cyclone separator 7 and a plurality of air outlets connected to the main furnace water-cooled air chamber 10, and the high-temperature flue gas can be discharged from the air outlet into the main furnace water-cooled air chamber 10, so that the high-temperature flue gas is distributed more evenly, thereby making the temperature distribution of the main furnace 1 more uniform.

[0041] In this embodiment, the main air distribution plate 3 and the auxiliary air distribution plate 4 are both used to carry bed material. The main furnace 1 and the auxiliary furnace 2 are connected. The bed material in the main furnace 1 can be transported to the auxiliary furnace 2. The auxiliary furnace 2 is started using the bed material in the main furnace 1 to achieve secondary application of the bed material and reduce the amount of bed material used. In addition, the hot bed material in the main furnace 1 is directly used to reduce the energy consumed in heating the bed material.

[0042] In the actual design, in order to transport the bed material in the main furnace 1 to the auxiliary furnace 2, a transport connecting pipe 5 is arranged between the main furnace 1 and the auxiliary furnace 2, and the two ends of the transport connecting pipe 5 are respectively connected to the main furnace 1 and the auxiliary furnace 2, and the two ends of the transport connecting pipe 5 are respectively arranged above the main air distribution plate 3 and the auxiliary air distribution plate 4, and the bed material carried on the main air distribution plate 3 can be output to the auxiliary air distribution plate 4 through the transport connecting pipe 5.

[0043] In this embodiment, the end of the conveying connecting pipe 5 connected to the main furnace 1 is arranged to be higher than the end of the conveying connecting pipe 5 connected to the auxiliary furnace 2, and gravity is used to transport the bed material. When this transportation method is adopted, in order to control the transportation amount of the bed material, a control valve 6 is also provided on the conveying connecting pipe 5. When feeding is required, the control valve 6 is opened. After the feeding amount requirement is met, the control valve 6 is closed to stop the feeding.

[0044] In other embodiments, other feeding methods may also be used, such as providing a feeding pump or a vibrating feeding device, etc., as long as one-way feeding from the main furnace 1 to the auxiliary furnace 2 can be achieved.

[0045] In order to further improve the auxiliary furnace system and enable the auxiliary furnace system to have the ability to continuously sulfurize and generate high-temperature flue gas, it is also necessary to set a fluidizing air device and a feeding device in the auxiliary furnace system.

[0046] Reference Figure 1 As shown, the auxiliary furnace system also includes: an auxiliary fluidizing air duct 11 connected to the auxiliary furnace water-cooled air chamber and a fluidizing air valve 12 arranged on the auxiliary fluidizing air duct 11, and the auxiliary fluidizing air duct 11 continuously provides air for sulfurization to sulfurize the bed material in the auxiliary furnace 2 and generate high-temperature flue gas.

[0047] Specifically, when the auxiliary fluidizing air duct 11 is set, it can be connected to an independent fluidizing fan to independently provide air for vulcanization to the auxiliary fluidizing air duct 11, or it can be connected to the mainstream fluidizing air system to provide air for vulcanization to the auxiliary fluidizing air duct 11 through the mainstream fluidizing air system.

[0048] Reference Figure 1 As shown, the auxiliary furnace system also includes: an auxiliary coal feeder 13 connected to the auxiliary furnace 2, and the auxiliary coal feeder 13 continuously transports bed material into the auxiliary furnace 2 to ensure the supply of bed material in the auxiliary furnace 2, so that the auxiliary furnace 2 can continuously generate high-temperature flue gas.

[0049] Specifically, the inner walls of the main furnace 1 and the auxiliary furnace 2 are cast with a refractory layer, which can improve the insulation effect, make the internal temperature of the main furnace 1 and the auxiliary furnace 2 high, increase the combustion temperature of the bed material, and improve the burnout rate of the bed material.

[0050] In addition, water cooling pipes are buried in the refractory layer, which can increase the heat exchange capacity when the pressure fire treatment is carried out, thereby increasing the evaporation capacity of the boiler at low load.

[0051] The specific peak-shaving process of the two-stage series-connected deep peak-shaving circulating fluidized bed boiler of the present invention is as follows:

[0052] Before the boiler performs deep peak regulation and fire suppression, the control valve 6 is opened to allow the hot bed material in the main furnace 1 to enter the auxiliary air distribution plate 4 in the auxiliary furnace 2 through the conveying connecting pipe 5. When the amount of bed material in the auxiliary furnace 2 meets the operating requirements, the control valve 6 is closed.

[0053] When the main furnace 1 of the boiler is quenched for deep peak regulation, the fluidizing air valve 12 installed on the auxiliary fluidizing air duct 11 is opened to fluidize the bed material in the auxiliary furnace 2, and then the auxiliary coal feeder 13 is used to continuously add bed material to the auxiliary furnace 2 for combustion; the high-temperature flue gas generated by the combustion enters the main furnace 1 from the main furnace water-cooled air chamber 10 through the insulated connecting pipe 9. After the high-temperature flue gas enters the main furnace 1, on the one hand, it heats the bed material to make the temperature of the bed material more uniform, and on the other hand, it transfers heat to the heating surface of the main furnace 1, so that qualified steam is generated during the quenching period to supply the steam turbine to maintain low-output operation.

[0054] During the ignition of the main furnace 1, the high-temperature flue gas can heat the primary air of the main furnace 1, so that the temperature of the primary air is significantly increased, so that the main furnace 1 can be started at a lower bed temperature, thereby further extending the ignition time.

[0055] During the ignition of the main furnace 1, the high-temperature flue gas can heat the primary air of the main boiler, so that the temperature of the primary air is significantly increased, reducing the amount of fuel oil used for ignition.

[0056] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A two-stage series deep peak-shaving circulating fluidized bed boiler, characterized in that: include: The main furnace system comprises: a main furnace, a main air distribution plate arranged in the main furnace, and a main furnace water-cooling air chamber arranged below the main air distribution plate; An auxiliary furnace system, comprising: an auxiliary furnace, an auxiliary air distribution plate arranged in the auxiliary furnace, an auxiliary furnace water-cooled air chamber arranged below the auxiliary air distribution plate, and an auxiliary furnace cyclone separator communicated with the auxiliary furnace; Wherein: the main air distribution plate and the auxiliary air distribution plate are both used to carry bed materials, the main furnace and the auxiliary furnace are connected, and the bed materials in the main furnace can be transported to the auxiliary furnace; The flue gas outlet of the auxiliary furnace cyclone separator is connected to the main furnace water-cooling air chamber, and the high-temperature flue gas generated by the combustion of bed materials in the auxiliary furnace can be discharged into the main furnace water-cooling air chamber through the auxiliary furnace cyclone separator.

2. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 1 is characterized in that: A transport connecting pipe is provided between the main furnace and the auxiliary furnace, and both ends of the transport connecting pipe are respectively connected to the main furnace and the auxiliary furnace, and both ends of the transport connecting pipe are respectively provided above the main air distribution plate and the auxiliary air distribution plate.

3. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 2 is characterized in that: The end of the transport connecting pipe communicating with the main furnace is higher than the end of the transport connecting pipe communicating with the auxiliary furnace.

4. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 2 is characterized in that: A control valve is also provided on the delivery connecting pipe.

5. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 1 is characterized in that: The auxiliary furnace cyclone separator and the main furnace water-cooling air chamber are connected via a heat-insulating connecting pipe.

6. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 5 is characterized in that: The heat-insulating connecting pipe has an air inlet connected to the auxiliary furnace cyclone separator and a plurality of air outlets connected to the main furnace water-cooled air chamber, and high-temperature flue gas can be discharged into the main furnace water-cooled air chamber from the air outlets.

7. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 1 is characterized in that: The auxiliary furnace system further includes: an auxiliary fluidizing air duct connected to the auxiliary furnace water-cooling air chamber and a fluidizing air valve arranged on the auxiliary fluidizing air duct.

8. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 7 is characterized in that: The auxiliary fluidizing air duct is communicated with an independent fluidizing air fan or a mainstream fluidizing air system.

9. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 1, characterized in that: The auxiliary furnace system further includes: an auxiliary coal feeder connected to the auxiliary furnace, and the auxiliary coal feeder continuously transports bed material into the auxiliary furnace.

10. The two-stage series deep peak-shaving circulating fluidized bed boiler according to claim 1, characterized in that: The inner walls of the main furnace and the auxiliary furnace are both cast with refractory layers, in which water cooling pipes are buried.

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