Biomass resource coupled coal-fired unit

Abstract

The utility model discloses a kind of coal-fired units of biomass resource coupling coal powder, including hearth, coal fuel system and biomass fuel system, biomass fuel system includes sequentially connected primary dryer, secondary dryer and pyrolysis reactor, primary dryer carries out preliminary drying to biomass using flue gas waste heat of boiler tail flue, secondary dryer carries out depth drying by the steam latent heat of steam turbine extraction steam system, pyrolysis reactor is rapidly pyrolyzed to dried biomass by external high-temperature gas, pyrolysis product is connected with burner through biomass delivery pipeline.The unit reduces biomass moisture content through two-stage drying, improves fuel heat value, improves energy utilization efficiency using flue gas waste heat and steam latent heat, pyrolysis reactor realizes the rapid pyrolysis of biomass, provides suitable product for subsequent combustion, solves the problem that biomass moisture is high and leads to unstable combustion, improves combustion efficiency and energy utilization rate, ensures the stable operation of coal-fired unit.

Description

Technical Field

[0001] This utility model relates to the field of coal-fired power unit technology, and in particular to a coal-fired power unit that couples biomass resources with pulverized coal. Background Technology

[0002] In the field of co-combustion technology of coal-fired power units and biomass, when biomass is directly co-fired in traditional coal-fired power units, the biomass (such as straw, agricultural and forestry waste) naturally contains a large amount of moisture. This moisture significantly reduces the overall calorific value of the fuel upon direct entry into the combustion system, leading to a sharp drop in combustion temperature and consequently causing problems such as unstable combustion and easy flame extinguishing. Furthermore, existing technologies simply process biomass before mixing it with pulverized coal, without deep drying and pyrolysis of the biomass. This results in low combustion efficiency of the biomass-coal mixture, making it difficult to meet the stable operation requirements of coal-fired power units under different load conditions. Unstable drying effects further affect the reliability of subsequent combustion, hindering the large-scale application of biomass in coal-fired power units.

[0003] Therefore, it is necessary to propose a coal-fired power unit that couples biomass resources with pulverized coal to solve the above problems. Utility Model Content

[0004] The purpose of this invention is to provide a coal-fired power unit that couples biomass resources with pulverized coal, in order to solve the problems that the large amount of moisture in biomass will significantly reduce the overall calorific value of the fuel and that the drying effect will affect the reliability of subsequent combustion.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A coal-fired power unit coupled with biomass resources includes a furnace, a coal fuel system, and a biomass fuel system. The biomass fuel system includes a biomass pretreatment unit, which comprises a primary dryer, a secondary dryer, and a pyrolysis reactor connected in sequence. The primary dryer is connected to the boiler tail flue via a pipeline to perform preliminary drying of the biomass using waste heat from the flue gas. The secondary dryer is connected to the steam extraction system of the steam turbine via a pipeline to perform deep drying of the biomass using latent heat of the steam. The pyrolysis reactor is connected to the secondary dryer via a pipeline. A high-temperature gas inlet is provided at the top of the pyrolysis reactor, which is connected to an external high-temperature gas supply device for rapid pyrolysis of the dried biomass. The bottom outlet of the pyrolysis reactor is connected to the burner via a biomass conveying pipeline.

[0007] Preferably, the primary dryer is a rotary drum dryer, which is equipped with spiral blades and lifting plates inside. A first moisture detector is installed at the inlet of the primary dryer, and a second moisture detector is installed at the outlet. The first and second moisture detectors are respectively connected to the control system, which can adjust the speed of the primary dryer and the flue gas flow rate according to the moisture content.

[0008] Preferably, the secondary dryer is a tube bundle dryer, including a shell and a tube bundle disposed within the shell. The tube bundle is connected to the steam extraction system of the steam turbine. The shell is provided with a biomass inlet and an outlet. A dispersing device is provided at the biomass inlet. A third moisture detector is provided at the outlet of the secondary dryer. The third moisture detector is connected to the control system. The control system adjusts the steam flow rate and the residence time of biomass in the secondary dryer according to the moisture content.

[0009] Preferably, the pyrolysis reactor includes a reaction chamber and a high-temperature gas distributor. The high-temperature gas distributor is located inside the reaction chamber and is connected to a high-temperature gas inlet. A flow regulating valve and a temperature sensor are installed on the high-temperature gas inlet. The temperature sensor is connected to a control system. The flow regulating valve is an electrically controlled valve and is electrically connected to the control system. The control system adjusts the opening degree of the flow regulating valve according to the temperature inside the pyrolysis reactor.

[0010] Preferably, the bottom of the pyrolysis reactor is also provided with a slag discharge port, and an electrically controlled slag discharge valve is provided at the slag discharge port. The electrically controlled slag discharge valve is electrically connected to the control system, and the control system controls the opening and closing of the electrically controlled slag discharge valve according to the pressure value detected by the pressure sensor at the slag discharge port.

[0011] Preferably, the burner is connected to a pulverized coal pipeline, the burner is connected to the furnace, and the pulverized coal pipeline is connected to the coal fuel system.

[0012] The technical effects and advantages of this utility model are as follows:

[0013] 1. The waste heat of flue gas from the boiler tail flue is used to perform preliminary drying of biomass, realizing energy recovery and utilization and improving energy utilization efficiency. The latent heat of steam from the steam turbine extraction system is used for deep drying, further reducing the moisture content of biomass and increasing the calorific value of fuel.

[0014] 2. The pyrolysis reactor introduces high-temperature gas through a high-temperature gas inlet. The high-temperature gas distributor evenly distributes the gas. Combined with temperature sensors and flow regulating valves, the control system adjusts the gas input according to the temperature inside the reactor, enabling the dried biomass to pyrolyze rapidly and provide suitable products for subsequent combustion. The slag discharge port and electrically controlled slag discharge valve at the bottom of the pyrolysis reactor can control the slag discharge according to the pressure value detected by the pressure sensor, ensuring the normal working environment inside the reactor. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a coal-fired power unit structure that couples biomass resources with pulverized coal, according to the present invention.

[0016] In the diagram: 1. Primary dryer; 2. Secondary dryer; 3. Pyrolysis reactor; 4. Boiler; 5. Steam turbine extraction system; 6. High-temperature gas inlet; 7. Biomass conveying pipeline; 8. Burner; 9. First moisture detector; 10. Second moisture detector; 11. Dispersing device; 12. Third moisture detector; 13. Flow regulating valve; 14. Temperature sensor; 15. Slag discharge port; 16. Electrically controlled slag discharge valve; 17. Pulverized coal pipeline. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] This utility model provides, for example Figure 1 The illustrated coal-fired power unit, which couples biomass resources with pulverized coal, includes a furnace, a coal fuel system, and a biomass fuel system. The biomass fuel system includes a biomass pretreatment unit, which comprises a primary dryer 1, a secondary dryer 2, and a pyrolysis reactor 3 connected in sequence. The primary dryer 1 is connected to the tail flue of the boiler 4 via a pipeline, utilizing the waste heat of the flue gas to perform preliminary drying of the biomass. The secondary dryer 2 is connected to the steam extraction system 5 of the steam turbine via a pipeline, utilizing the latent heat of the steam to perform deep drying of the biomass. The pyrolysis reactor 3 is connected to the secondary dryer 2 via a pipeline. A high-temperature gas inlet 6 is provided at the top of the pyrolysis reactor 3, which is connected to an external high-temperature gas supply device for rapid pyrolysis of the dried biomass. The bottom outlet of the pyrolysis reactor 3 is connected to a burner 8 via a biomass conveying pipeline 7.

[0019] Furthermore, the primary dryer 1 is a rotary drum dryer with spiral blades and lifting plates inside. A first moisture detector 9 is installed at the inlet of the primary dryer 1, and a second moisture detector 10 is installed at the outlet. The first moisture detector 9 and the second moisture detector 10 are respectively connected to the control system. The control system can adjust the rotation speed and flue gas flow rate of the primary dryer 1 according to the moisture content.

[0020] Furthermore, the secondary dryer 2 is a tube bundle dryer, including a shell and a tube bundle installed inside the shell. The tube bundle is connected to the steam extraction system 5 of the steam turbine. The shell is provided with a biomass inlet and an outlet. A dispersing device 11 is provided at the biomass inlet. A third moisture detector 12 is provided at the outlet of the secondary dryer 2. The third moisture detector 12 is connected to the control system. The control system adjusts the steam flow rate and the residence time of biomass in the secondary dryer 2 according to the moisture content.

[0021] Furthermore, the pyrolysis reactor 3 includes a reaction chamber and a high-temperature gas distributor. The high-temperature gas distributor is installed inside the reaction chamber and is connected to the high-temperature gas inlet 6. The high-temperature gas inlet 6 is equipped with a flow regulating valve 13 and a temperature sensor 14. The temperature sensor 14 is connected to the control system. The flow regulating valve 13 is an electrically controlled valve and is electrically connected to the control system. The control system adjusts the opening degree of the flow regulating valve 13 according to the temperature inside the pyrolysis reactor 3.

[0022] Furthermore, a slag discharge port 15 is provided at the bottom of the pyrolysis reactor 3, and an electrically controlled slag discharge valve 16 is provided at the slag discharge port 15. The electrically controlled slag discharge valve 16 is electrically connected to the control system, and the control system controls the opening and closing of the electrically controlled slag discharge valve 16 according to the pressure value detected by the pressure sensor at the slag discharge port 15.

[0023] Furthermore, a pulverized coal pipe 17 is connected to the burner 8, the burner 8 is connected to the furnace, and the pulverized coal pipe 17 is connected to the coal fuel system.

[0024] In this embodiment of the invention, the working process of the coal-fired unit mainly includes biomass pretreatment, pulverized coal supply, and combustion of both in the burner and furnace. During biomass pretreatment, biomass fuel enters the primary dryer 1. Waste heat from the flue gas at the tail end of the boiler 4 is introduced through pipes to initially dry the biomass. Spiral blades within the dryer 1 propel the biomass forward, and lifting plates lift it, increasing the contact area with the flue gas and improving drying efficiency. A first moisture detector 9 at the inlet and a second moisture detector 10 at the outlet detect the moisture content in real time and transmit the data to the control system. The control system adjusts the rotation speed and flue gas flow rate of the primary dryer 1 accordingly to ensure the initial drying effect. The biomass dried in the primary dryer 1 enters the secondary dryer 2. Steam from the turbine extraction system 5 passes through the tube bundles to further dry the biomass. A dispersing device 11 at the biomass inlet disperses any agglomerated biomass, making the drying more uniform. A third moisture detector 12 at the outlet detects the moisture content, and the control system adjusts the steam flow rate and the residence time of the biomass in the dryer based on this data to achieve deep drying.

[0025] Deeply dried biomass enters pyrolysis reactor 3. High-temperature gas is supplied to the reactor through high-temperature gas inlet 6, and distributed evenly by a high-temperature gas distributor. Temperature sensor 14 monitors the reactor temperature in real time. The control system adjusts the opening of flow regulating valve 13 based on the temperature data to control the input of high-temperature gas, enabling rapid pyrolysis of the dried biomass. The pyrolysis products are transported from the bottom outlet of the reactor to the burner 8 through biomass conveying pipe 7. Simultaneously, a pressure sensor at the slag discharge port 15 at the bottom of the reactor detects the pressure value. The control system controls the opening and closing of the electrically controlled slag discharge valve 16 based on this value to discharge the pyrolysis waste. While the pyrolysis products are being transported to the burner 8, pulverized coal from the coal fuel system is transported to the burner 8 through pulverized coal pipe 17 to mix with the biomass pyrolysis products. The burner 8 is connected to the furnace, injecting the mixed fuel into the furnace for combustion and heat release.

[0026] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A coal-fired power unit coupled with biomass resources and pulverized coal, comprising a furnace, a coal fuel system, and a biomass fuel system, characterized in that: The biomass fuel system includes a biomass pretreatment unit, which comprises a primary dryer, a secondary dryer, and a pyrolysis reactor connected in sequence. The primary dryer is connected to the boiler tail flue via a pipeline to perform preliminary drying of the biomass using waste heat from the flue gas. The secondary dryer is connected to the steam extraction system of the steam turbine via a pipeline to perform deep drying of the biomass using latent heat of the steam. The pyrolysis reactor is connected to the secondary dryer via a pipeline. A high-temperature gas inlet is provided at the top of the pyrolysis reactor, which is connected to an external high-temperature gas supply device for rapid pyrolysis of the dried biomass. The bottom outlet of the pyrolysis reactor is connected to a burner via a biomass conveying pipeline.

2. The biomass resource coupled pulverized coal-fired unit of claim 1, wherein: The primary dryer is a rotary drum dryer with spiral blades and lifting plates inside. A first moisture detector is installed at the inlet of the primary dryer, and a second moisture detector is installed at the outlet. The first and second moisture detectors are respectively connected to the control system, which can adjust the speed of the primary dryer and the flue gas flow rate according to the moisture content.

3. The biomass resource coupled pulverized coal-fired unit of claim 1, wherein: The secondary dryer is a tube bundle dryer, including a shell and a tube bundle disposed within the shell. The tube bundle is connected to the steam extraction system of the steam turbine. The shell is provided with a biomass inlet and an outlet. A dispersing device is provided at the biomass inlet. A third moisture detector is provided at the outlet of the secondary dryer. The third moisture detector is connected to the control system. The control system adjusts the steam flow rate and the residence time of biomass in the secondary dryer according to the moisture content.

4. The biomass resource coupled pulverized coal-fired unit of claim 1, wherein: The pyrolysis reactor includes a reaction chamber and a high-temperature gas distributor. The high-temperature gas distributor is located inside the reaction chamber and is connected to a high-temperature gas inlet. A flow regulating valve and a temperature sensor are installed on the high-temperature gas inlet. The temperature sensor is connected to a control system. The flow regulating valve is an electrically controlled valve and is electrically connected to the control system. The control system adjusts the opening degree of the flow regulating valve according to the temperature inside the pyrolysis reactor.

5. The biomass resource coupled pulverized coal-fired unit of claim 4, wherein: The bottom of the pyrolysis reactor is also provided with a slag discharge port, and an electrically controlled slag discharge valve is provided at the slag discharge port. The electrically controlled slag discharge valve is electrically connected to the control system, and the control system controls the opening and closing of the electrically controlled slag discharge valve according to the pressure value detected by the pressure sensor at the slag discharge port.

6. The biomass resource coupled pulverized coal-fired unit of claim 1, wherein: The burner is connected to a pulverized coal pipeline, the burner is connected to the furnace, and the pulverized coal pipeline is connected to the coal fuel system.

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