A system and method for increasing the hot air temperature of a coal-fired boiler

Abstract

The present invention relates to the technical field of energy conservation of coal-fired boilers, specifically a system and method for increasing the temperature of hot air from a coal-fired boiler. The system includes a hot air heater, which is arranged in a hot air duct at the outlet of an air preheater. The outlet end of the hot air heater is in communication with the boiler. The hot air heater is connected to the high-pressure cylinder of a steam turbine via a hot air heater heat source pipeline. The high-pressure cylinder of the steam turbine is used to provide a heat source to the hot air heater via the hot air heater heat source pipeline. The present invention utilizes the extraction steam from the high-pressure cylinder of the steam turbine to heat the hot air at the outlet of the air preheater. On the one hand, the present invention improves the stability of boiler combustion, which is beneficial to the stable operation of the unit. On the other hand, it improves the burnout of pulverized coal, which is beneficial to improving the combustion efficiency of the boiler and improving the economy. Thirdly, it can reduce the heat consumption rate of the steam turbine and reduce the coal consumption of the unit for power generation.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conservation of coal-fired boilers, and in particular to a system and method for increasing the temperature of hot air from a coal-fired boiler. Background Art

[0002] Solar and wind power generation have experienced rapid growth in recent years. However, due to the periodicity and instability of these two power sources, the curtailment rates are high, and new energy sources are unable to support the energy needs of my country's development. Therefore, the stability, economy, and safety of coal-fired units continue to receive widespread and ongoing attention.

[0003] In order to ensure the normal operation of coal-fired units, coal, air and water are the three essential elements for the operation of the units. Among them, air is one of the most important prerequisites in the daily production process of coal-fired boilers.

[0004] To ensure normal combustion in coal-fired boilers, the hot air entering the boiler must reach a certain temperature level. If the hot air temperature is too low, firstly, it will cause unstable combustion in the boiler, large fluctuations in unit parameters, boiler coking, and shortened unit life; secondly, it will lead to increased carbon content in the boiler's fly ash, reduced boiler efficiency, increased unit coal consumption, and reduced economic efficiency; thirdly, it will cause increased NOx content at the boiler outlet, and environmental protection parameters will not meet standards.

[0005] At present, all coal-fired boilers in my country use air preheaters to heat cold air, thereby increasing the temperature of the hot air entering the boiler, thereby promoting boiler combustion, improving boiler efficiency, and reducing coal consumption for power generation. However, this method is limited by the heat transfer end difference at the air preheater outlet. The hot air temperature at the air preheater outlet cannot reach a very high level, especially when the boiler load is low. The hot air temperature will drop more significantly, and the boiler combustion will also be greatly affected.

[0006] Therefore, the present invention invents a system and method for increasing the temperature of hot air from a coal-fired boiler. Summary of the Invention

[0007] The present invention provides a system and method for increasing the temperature of hot air from a coal-fired boiler, in order to solve the technical problems raised by the above-mentioned background technology.

[0008] To solve the above technical problems, the present invention discloses a system and method for increasing the hot air temperature of a coal-fired boiler. The system includes a hot air heater, which is arranged in the hot air duct at the outlet of an air preheater. The outlet end of the hot air heater is communicated with the boiler. The hot air heater is connected to the high-pressure cylinder of a steam turbine through a hot air heater heat source pipeline. The high-pressure cylinder of the steam turbine is used to provide a heat source to the hot air heater through the hot air heater heat source pipeline.

[0009] Preferably, a fan is provided at the cold air duct at the inlet of the air preheater, and the fan is used to pressurize the cold air and press it into the air preheater. The cold air is heated in the air preheater and becomes hot air at the outlet of the air preheater. The heat source for the temperature rise of the cold air comes from the hot flue gas. The hot flue gas is cooled to become cold flue gas after releasing heat in the air preheater. The hot air at the outlet of the air preheater is heated again at the hot air heater and becomes hot air at the outlet of the hot air heater.

[0010] Preferably, the heat source pipeline of the hot air heater is provided with a steam turbine high-pressure cylinder, a hot air heater, a steam turbine extraction heater and a regulating valve;

[0011] The high-temperature HHP extraction steam of the turbine high-pressure cylinder is divided into main HHP extraction steam and bypass HHP extraction steam. The main HHP extraction steam enters the hot air heater to heat the hot air at the air preheater outlet. The main HHP extraction steam is cooled in the hot air heater and becomes hot air heater exhaust steam. The bypass HHP extraction steam is mixed with the hot air heater exhaust steam to become HHP inlet steam, which is then sent to the turbine extraction heater.

[0012] A regulating valve is installed on the bypass high-temperature high-pressure steam extraction pipeline. The regulating valve is used to adjust the flow distribution of the main high-temperature high-pressure steam extraction pipeline and the bypass high-temperature high-pressure steam extraction pipeline, thereby achieving the purpose of regulating the hot air at the outlet of the hot air heater.

[0013] Preferably, an air filter assembly is provided between the air preheater and the fan, and the air filter assembly is used to filter the cold air.

[0014] Preferably, the air filter assembly comprises:

[0015] A filter assembly housing is provided with a cold air inlet chamber and a cold air buffer chamber. The cold air enters the cold air buffer chamber through the cold air inlet chamber and is filtered before being discharged to the air preheater through the cold air buffer chamber.

[0016] A filter screen, wherein the filter screen is fixedly connected in the cold air buffer chamber;

[0017] A gate plate is connected to the cold air inlet chamber by sliding up and down. A sliding rod is fixedly connected to the gate plate. The sliding rod is connected to the filter screen by sliding up and down. A buffer elastic member is sleeved on the sliding rod. One end of the buffer elastic member is fixedly connected to the filter screen, and the other end of the buffer elastic member is fixedly connected to the gate plate.

[0018] Two symmetrically arranged arc-shaped electromagnets, the arc-shaped electromagnets being fixedly connected in the cold air buffer chamber;

[0019] A rotating wheel, wherein a rotating shaft is fixedly connected to the rotating wheel, and the rotating shaft is rotatably connected to the cold air buffer chamber. A rotating drive member is provided on the rotating shaft, and the rotating drive member is used to drive the rotating shaft to rotate. A wire is provided on the hub of the rotating wheel, and a first conductive disk is provided on one end surface of the rotating wheel, and the first conductive disk is electrically connected to the wire. A second conductive disk is fixedly connected to the inner wall of the cold air buffer chamber, and the first conductive disk is in contact with the second conductive disk;

[0020] A heating lamp body is fixedly connected in the cold air buffer chamber and is electrically connected to the second conductive disk.

[0021] Preferably, a combustion-supporting gas adding component is provided between the hot air heater and the boiler, and the combustion-supporting gas adding component is used to add combustion-supporting gas into the boiler.

[0022] Preferably, the combustion-supporting gas includes any one or more of oxygen, ozone and fluorine.

[0023] Preferably, the hot air heater is provided with a hot air heater outlet hot air monitoring system, which is electrically connected to the regulating valve. The hot air heater outlet hot air monitoring system is used to monitor the working state of the hot air heater and adjust the regulating valve when the working state of the hot air heater is not good, thereby adjusting the flow distribution of the main high-temperature high-pressure steam extraction and the bypass high-temperature high-pressure steam extraction, so as to achieve the purpose of regulating the hot air at the hot air heater outlet.

[0024] Preferably, the hot air monitoring system at the outlet of the hot air heater includes:

[0025] a first temperature sensor, the first temperature sensor being arranged at the hot air inlet of the air preheater outlet of the hot air heater, and being used to detect the temperature at the hot air inlet of the air preheater outlet of the hot air heater;

[0026] a second temperature sensor, the second temperature sensor being arranged at the main high-temperature high-pressure steam extraction inlet of the hot air heater, for detecting the temperature at the main high-temperature high-pressure steam extraction inlet of the hot air heater;

[0027] a third temperature sensor, the third temperature sensor being disposed at a hot air outlet of the hot air heater and configured to detect a temperature of the hot air at the hot air outlet of the hot air heater;

[0028] a first flow rate sensor, the first flow rate sensor being arranged at the hot air inlet of the air preheater outlet of the hot air heater, and being used to detect the flow rate of the hot air at the hot air inlet of the air preheater outlet of the hot air heater;

[0029] a second flow rate sensor, the second flow rate sensor being arranged at the main high-temperature high-pressure steam extraction inlet of the hot air heater, and being used to detect the flow rate of the hot air at the air preheater outlet at the main high-temperature high-pressure steam extraction inlet of the hot air heater;

[0030] a third flow rate sensor, the third flow rate sensor being arranged at the hot air outlet of the hot air heater, and being used for detecting the flow rate of the hot air at the hot air outlet of the hot air heater;

[0031] a volume flow sensor, the volume flow sensor being arranged at a hot air outlet of the hot air heater and being used for detecting a volume flow rate of hot air at a hot air outlet of the hot air heater;

[0032] a wind force sensor, the wind force sensor being arranged at the hot air outlet of the hot air heater and being used for detecting the wind force of the hot air at the hot air outlet of the hot air heater;

[0033] A controller is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow velocity sensor, the second flow velocity sensor, the third flow velocity sensor, the volume flow sensor, the wind sensor, and the regulating valve. The controller controls the operation of the regulating valve based on the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow velocity sensor, the second flow velocity sensor, the third flow velocity sensor, the volume flow sensor, and the wind sensor, comprising the following steps:

[0034] Step 1: Calculate the actual temperature stability coefficient of the hot air at the outlet of the hot air heater based on the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow velocity sensor, the second flow velocity sensor, the third flow velocity sensor, the volume flow sensor, and the wind force sensor:

[0035]

[0036] in, is the actual temperature stability coefficient of the hot air at the outlet of the hot air heater, α is the detection value error coefficient of the volume flow sensor, Q v is the detection value of the volume flow sensor, Q m0is the preset mass flow rate of the hot air at the outlet of the hot air heater, g is the acceleration of gravity, which is 9.81, θ1 is the detection value of the first flow velocity sensor, θ2 is the detection value of the second flow velocity sensor, θ3 is the detection value of the third flow velocity sensor, N re is the detection value of the wind sensor, t is the detection cycle of the hot air monitoring system at the outlet of the hot air heater, A u A is the opening area of the hot air inlet at the outlet of the air preheater of the hot air heater, 2i A is the opening area of the main high-temperature high-pressure extraction steam inlet of the hot air heater, o is the opening area of the hot air outlet of the hot air heater, T0 is the preset temperature of the hot air at the hot air outlet of the hot air heater, T 1a is the detection value of the first temperature sensor in the ath detection cycle, T 2a is the detection value of the second temperature sensor in the ath detection cycle, T 3a is the detection value of the third temperature sensor in the ath detection cycle, T 1(a+1) is the detection value of the first temperature sensor in the a+1th detection cycle, T 2(a+1) is the detection value of the second temperature sensor in the a+1th detection cycle, T 3(a+1) is the detection value of the third temperature sensor in the a+1th detection cycle, and X represents the total number of cycles of operation of the hot air monitoring system at the outlet of the hot air heater;

[0037] Step 2: The controller compares the actual temperature stability coefficient of the hot air at the hot air heater outlet of the hot air heater with the preset temperature stability coefficient range of the hot air at the hot air heater outlet of the hot air heater. If the actual temperature stability coefficient of the hot air at the hot air heater outlet of the hot air heater exceeds the preset temperature stability coefficient range of the hot air at the hot air heater outlet of the hot air heater, the controller adjusts the regulating valve to adjust the flow distribution of the main high-temperature high-pressure steam extraction and the bypass high-temperature high-pressure steam extraction, so that the actual temperature stability coefficient of the hot air at the hot air heater outlet of the hot air heater falls within the preset temperature stability coefficient range of the hot air at the hot air heater outlet of the hot air heater.

[0038] A method for increasing the temperature of hot air from a coal-fired boiler comprises the following steps:

[0039] The cold air enters the air preheater to absorb heat and heat up, becoming the hot air at the air preheater outlet. The hot air at the air preheater outlet is heated again at the hot air heater and becomes the hot air at the hot air heater outlet. The hot air at the hot air heater outlet is sent to the boiler to participate in combustion. The heat source of the hot air heater comes from the high-pressure cylinder of the steam turbine.

[0040] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0042] Figure 1 Schematic diagram of the overall system of the present invention.

[0043] Figure 2 This is a schematic diagram of the heat source pipeline of the hot air heater of the present invention.

[0044] Figure 3 This is a schematic diagram of the installation positions of the air filter assembly and the combustion-supporting gas adding assembly of the present invention.

[0045] Figure 4 This is a schematic structural diagram of the air filter assembly of the present invention.

[0046] Figure 5 It is a side view of the runner of the present invention.

[0047] Figure: 1. Boiler; 2. Steam turbine high-pressure cylinder; 3. Steam turbine high-temperature high-pressure heater extraction steam; 4. Hot air heater; 5. Air preheater; 6. Fan; 7. Hot air at air preheater outlet; 8. Hot air at hot air heater outlet; 9. Hot air heater exhaust steam; 10. Steam turbine high-pressure heater extraction steam heater; 11. Hot flue gas; 12. Cold flue gas; 13. Cold air; 14. Bypass high-temperature high-pressure heater extraction steam; 15. Control valve; 16. High-pressure heater inlet steam; 17. Main high-temperature high-pressure heater extraction steam; 18. Air Air filter assembly; 180, filter assembly housing; 1800, cold air inlet chamber; 1801, cold air buffer chamber; 1802, filter screen; 1803, gate; 1804, slide rod; 1805, buffer elastic member; 1806, arc-shaped electromagnet; 1807, rotor; 1808, rotating shaft; 1809, hub; 181, wire; 1810, heating lamp body; 1811, first conductive disk; 1812, second conductive disk; 19, combustion-supporting gas adding assembly. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0049] In addition, in the present invention, descriptions such as "first" and "second" are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present invention. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions and technical features between the various embodiments can be combined with each other, but this must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0050] The present invention provides the following embodiments:

[0051] Example 1

[0052] The embodiment of the present invention provides a system for increasing the temperature of hot air from a coal-fired boiler. Figure 1-5 As shown, it includes a hot air heater 4, which is arranged in the hot air duct at the outlet of the air preheater 5. The outlet end of the hot air heater 4 is connected to the boiler 1. The hot air heater 4 is connected to the high-pressure cylinder 2 of the steam turbine through a hot air heater heat source pipeline. The high-pressure cylinder 2 of the steam turbine is used to provide a heat source to the hot air heater 4 through the hot air heater heat source pipeline.

[0053] Preferably, a method for increasing the temperature of hot air from a coal-fired boiler comprises the following steps:

[0054] The cold air 13 enters the air preheater 5 to absorb heat and heat up, becoming the hot air 7 at the air preheater outlet. The hot air 7 at the air preheater outlet is heated again at the hot air heater 4 to become the hot air 8 at the hot air heater outlet. The hot air 8 at the hot air heater outlet is sent to the boiler 1 to participate in combustion. The heat source of the hot air heater 4 comes from the high-pressure cylinder 2 of the steam turbine.

[0055] Preferably, a combustion-supporting gas adding component 19 is provided between the hot air heater 4 and the boiler 1, and the combustion-supporting gas adding component 19 is used to add combustion-supporting gas into the boiler 1;

[0056] The combustion-supporting gas includes any one or more of oxygen, ozone and fluorine.

[0057] The working principle and beneficial effects of the above technical solution are as follows: the cold air 13 enters the air preheater 5 to absorb heat and heat up, becoming the hot air 7 at the air preheater outlet. The hot air 7 at the air preheater outlet is heated again in the hot air heater 4 to become the hot air 8 at the hot air heater outlet. The hot air 8 at the hot air heater outlet is sent to the boiler 1 to participate in combustion. The heat source of the hot air heater 4 comes from the high-pressure cylinder 2 of the steam turbine.

[0058] The present invention utilizes the extraction steam of the high-pressure cylinder 2 of the steam turbine to heat the hot air 7 at the outlet of the air preheater. On the one hand, it improves the stability of boiler combustion, which is beneficial to the stable operation of the unit; on the other hand, it improves the burnout of coal powder, which is beneficial to improving the combustion efficiency of the boiler and improving the economy; thirdly, it can reduce the heat consumption rate of the steam turbine and reduce the coal consumption of the unit for power generation.

[0059] Example 2

[0060] On the basis of the above embodiment 1, Figure 1 As shown, a fan 6 is provided at the cold air duct at the inlet of the air preheater 5. The fan 6 is used to pressurize the cold air 13 and press it into the air preheater 5. The cold air 13 is heated in the air preheater 5 and becomes hot air 7 at the air preheater outlet. The heat source for the temperature rise of the cold air 13 comes from the hot flue gas 11. The hot flue gas 11 releases heat in the air preheater 5 and then cools down to become cold flue gas 12. The hot air 7 at the air preheater outlet is heated again at the hot air heater 4 and becomes hot air 8 at the hot air heater outlet.

[0061] The working principle and beneficial effects of the above technical solution are as follows: the design of the fan 6 accelerates the heat exchange efficiency of the air preheater 5, thereby promoting boiler combustion and improving boiler efficiency.

[0062] Example 3

[0063] On the basis of Example 1, Figure 2 As shown, the hot air heater heat source pipeline is provided with a steam turbine high-pressure cylinder 2, a hot air heater 4, a steam turbine extraction heater 10 and a regulating valve 15;

[0064] The high-temperature high-pressure steam extraction 3 of the turbine high-pressure cylinder 2 is divided into main high-temperature high-pressure steam extraction 17 and bypass high-temperature high-pressure steam extraction 14. The main high-temperature high-pressure steam extraction 17 enters the hot air heater 4 to heat the hot air 7 at the outlet of the air preheater 5. The main high-temperature high-pressure steam extraction 17 is cooled in the hot air heater 4 and becomes hot air heater exhaust steam 9. The bypass high-temperature high-pressure steam extraction 14 is mixed with the hot air heater exhaust steam 9 to become high-pressure steam inlet steam 16. The high-pressure steam inlet steam 16 is sent to the turbine extraction heater 10.

[0065] A regulating valve 15 is installed on the bypass high-temperature high-pressure steam extraction pipeline 14, which is used to adjust the flow distribution of the main high-temperature high-pressure steam extraction 17 and the bypass high-temperature high-pressure steam extraction 14, so as to achieve the purpose of regulating the hot air 8 at the outlet of the hot air heater.

[0066] The working principle and beneficial effects of the above technical solution are as follows: the hot air heated by the air preheater 5 is first heated again by the hot air heater 4 and then sent to the boiler to participate in combustion; the heat source of the hot air heater 4 comes from the extraction steam of the steam turbine, and the steam extraction steam of the steam turbine is first sent to the hot air heater 4 to heat the hot air, and the exhaust steam of the hot air heater 4 returns to the steam turbine extraction heater 10 to continue heating the feed water or condensate.

[0067] Example 4

[0068] On the basis of Example 1, Figure 4 and 5 As shown,

[0069] An air filter assembly 18 is provided between the air preheater 5 and the fan 6, and the air filter assembly 18 is used to filter the cold air 13;

[0070] The air filter assembly 18 includes:

[0071] The filter assembly housing 180 is provided with a cold air inlet chamber 1800 and a cold air buffer chamber 1801. The cold air 13 enters the cold air buffer chamber 1801 through the cold air inlet chamber 1800 and is filtered, and then is discharged to the air preheater 5 through the cold air buffer chamber 1801.

[0072] Filter 1802, the filter 1802 is fixedly connected in the cold air buffer chamber 1801;

[0073] A gate plate 1803 is connected to the cold air inlet chamber 1800 by sliding up and down. A sliding rod 1804 is fixedly connected to the gate plate 1803. The sliding rod 1804 is connected to the filter 1802 by sliding up and down. A buffer elastic member 1805 is sleeved on the sliding rod 1804. One end of the buffer elastic member 1805 is fixedly connected to the filter 1802, and the other end of the buffer elastic member 1805 is fixedly connected to the gate plate 1803.

[0074] Two symmetrically arranged arc-shaped electromagnets 1806, the arc-shaped electromagnets 1806 are fixedly connected in the cold air buffer chamber 1801;

[0075] A rotating wheel 1807 is fixedly connected to a rotating shaft 1808, which is rotatably connected to the cold air buffer chamber 1801. The rotating shaft 1808 is provided with a rotating driving member, which is used to drive the rotating shaft 1808 to rotate. A wire 181 is provided on a hub 1809 of the rotating wheel 1807. One end face of the rotating wheel 1807 is provided with a first conductive disk 1811, which is electrically connected to the wire 181. A second conductive disk 1812 is fixedly connected to the inner wall of the cold air buffer chamber 1801, and the first conductive disk 1811 is in contact with the second conductive disk 1812.

[0076] The heating lamp body 1810 is fixedly connected to the cold air buffer chamber 1801 , and the heating lamp body 1810 is electrically connected to the second conductive disk 1812 .

[0077] The working principle and beneficial effects of the above technical solution are as follows: when working, the fan 6 drives the cold air 13 to enter the cold air inlet chamber 1800. When the cold air 13 in the cold air inlet chamber 1800 accumulates to a certain flow rate, the gate 1803 moves upward under the push of the cold air 13, so that the cold air 13 flows into the cold air buffer chamber 1801 through the gap between the gate 1803 and the inner wall of the cold air inlet chamber 1800. After the cold air 13 is filtered by the filter 1802, it drives the rotor 1807 to rotate, and the rotation of the rotor 1807 drives the cold air 13 to rotate. The wire 181 cuts the magnetic flux lines between the two arc-shaped electromagnets 1806, thereby generating an induced current in the wire 181. The induced current is conducted to the second conductive disk 1812 via the first conductive disk 1811, and then introduced into the heating lamp body 1810 via the second conductive disk 1812, providing electrical energy to the heating lamp body 1810, thereby causing the heating lamp body 1810 to heat the cold air 13. At the same time, the rotation of the rotor 1807 drives the filtered cold air 13 to be discharged from the cold air buffer chamber 1801 to the air preheater 5.

[0078] The air filter assembly 18 can filter, buffer and heat the cold air 13, thereby reducing the power consumption of the subsequent hot air heater 4 and the air preheater 5 when heating the cold air 13, and using the cold air 13 to generate electricity reduces the energy consumption of the heating lamp body 1810 during use.

[0079] Example 5

[0080] On the basis of Example 3, the hot air heater 4 is provided with a hot air monitoring system at the outlet of the hot air heater. The hot air monitoring system at the outlet of the hot air heater is electrically connected to the regulating valve 15. The hot air monitoring system at the outlet of the hot air heater is used to monitor the working state of the hot air heater 4 and adjust the regulating valve 15 when the working state of the hot air heater 4 is not good, thereby adjusting the flow distribution of the main high-temperature high-pressure steam extraction 17 and the bypass high-temperature high-pressure steam extraction 14, thereby achieving the purpose of regulating the hot air 8 at the outlet of the hot air heater;

[0081] The hot air monitoring system at the outlet of the hot air heater includes:

[0082] a first temperature sensor, the first temperature sensor being arranged at the hot air inlet 7 at the air preheater outlet of the hot air heater 4 and being used to detect the temperature at the hot air inlet 7 at the air preheater outlet of the hot air heater 4;

[0083] A second temperature sensor is provided at the inlet of the main high-temperature high-pressure steam extraction device 17 of the hot air heater 4, and is used to detect the temperature at the inlet of the main high-temperature high-pressure steam extraction device 17 of the hot air heater 4;

[0084] a third temperature sensor, the third temperature sensor being arranged at the outlet of the hot air heater 8 of the hot air heater 4 and being used for detecting the temperature of the hot air 8 at the outlet of the hot air heater 4;

[0085] a first flow velocity sensor, the first flow velocity sensor being arranged at the inlet of the hot air 7 at the air preheater outlet of the hot air heater 4, and being used for detecting the flow velocity of the hot air 7 at the inlet of the hot air 7 at the air preheater outlet of the hot air heater 4;

[0086] A second flow rate sensor is provided at the main high-temperature high-pressure steam extraction inlet 17 of the hot air heater 4, and is used to detect the flow rate of the hot air 7 at the air preheater outlet at the main high-temperature high-pressure steam extraction inlet 17 of the hot air heater 4;

[0087] a third flow rate sensor, the third flow rate sensor being arranged at the hot air outlet 8 of the hot air heater 4 and being used for detecting the flow rate of the hot air 8 at the hot air outlet 8 of the hot air heater 4;

[0088] a volume flow sensor, the volume flow sensor being arranged at the outlet of the hot air heater 8 of the hot air heater 4 and being used for detecting the volume flow of the hot air 8 at the outlet of the hot air heater 4;

[0089] a wind force sensor, the wind force sensor being arranged at the outlet of the hot air heater 8 of the hot air heater 4 and being used for detecting the wind force of the hot air 8 at the outlet of the hot air heater 4;

[0090] A controller is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow velocity sensor, the second flow velocity sensor, the third flow velocity sensor, the volume flow sensor, the wind sensor, and the regulating valve 15. The controller controls the regulating valve 15 based on the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow velocity sensor, the second flow velocity sensor, the third flow velocity sensor, the volume flow sensor, and the wind sensor, comprising the following steps:

[0091] Step 1: Based on the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow rate sensor, the second flow rate sensor, the third flow rate sensor, the volume flow sensor and the wind force sensor, calculate the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4:

[0092]

[0093] in, is the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4, a is the detection value error coefficient of the volume flow sensor, Q v is the detection value of the volume flow sensor, Q m0 is the preset mass flow rate of the hot air 8 at the outlet of the hot air heater 4, g is the acceleration of gravity, which is 9.81, θ1 is the detection value of the first flow velocity sensor, θ2 is the detection value of the second flow velocity sensor, θ3 is the detection value of the third flow velocity sensor, N re is the detection value of the wind sensor, t is the detection cycle of the hot air monitoring system at the outlet of the hot air heater, A 1i A is the opening area at the hot air inlet 7 of the air preheater outlet of the hot air heater 4, 2i A is the opening area at the inlet of the main high-temperature high-pressure extraction steam 17 of the hot air heater 4, o is the opening area of the hot air heater outlet 8 of the hot air heater 4, T0 is the preset temperature of the hot air heater outlet 8 of the hot air heater 4, T 1a is the detection value of the first temperature sensor in the ath detection cycle, T 2ais the detection value of the second temperature sensor in the ath detection cycle, T 3a is the detection value of the third temperature sensor in the ath detection cycle, T 1(a+1) is the detection value of the first temperature sensor in the a+1th detection cycle, T 2(a+1) is the detection value of the second temperature sensor in the a+1th detection cycle, T 3(a+1) is the detection value of the third temperature sensor in the a+1th detection cycle, and X represents the total number of cycles of operation of the hot air monitoring system at the outlet of the hot air heater;

[0094] Step 2: The controller compares the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4 with the preset temperature stability coefficient range of the hot air 8 at the outlet of the hot air heater 4. If the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4 exceeds the preset temperature stability coefficient range of the hot air 8 at the outlet of the hot air heater 4, the controller adjusts the regulating valve 15, thereby adjusting the flow distribution of the main high-temperature high-pressure steam extraction 17 and the bypass high-temperature high-pressure steam extraction 14, so that the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4 falls within the preset temperature stability coefficient range of the hot air 8 at the outlet of the hot air heater 4.

[0095] The working principle and beneficial effects of the above technical solution are as follows: the design of the hot air monitoring system at the hot air heater outlet can monitor the working status of the hot air heater 4 and adjust the regulating valve 15 when the hot air heater 4 is not in good working condition, thereby adjusting the flow distribution of the main high-temperature high-pressure steam extraction 17 and the bypass high-temperature high-pressure steam extraction 14, so as to achieve the purpose of regulating the hot air 8 at the hot air heater outlet, thereby maintaining a certain stability of the hot air 8 at the hot air heater outlet, thereby ensuring the stability and burnout of the boiler combustion;

[0096] When calculating the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4, the parameters of the hot air heater 4 itself are introduced, such as the difference between the size of the diameter of all air inlets and the size of the diameter of the air outlet |A 1i +A 2i -A o | In order to increase the pertinence of the calculation results, the detection value θ1 of the first flow velocity sensor, the detection value θ2 of the second flow velocity sensor, the detection value θ3 of the third flow velocity sensor, and the detection value N of the wind speed sensor are introduced at the same time. re, so that the calculation result is more accurate, when calculating the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4, in addition to considering the average temperature at the two inlets of the hot air heater 4 and the temperature difference between the inlet and the outlet, such as the detection value T of the first temperature sensor in the ath detection cycle 1a and the detection value T of the second temperature sensor in the ath detection cycle 2a Average temperature The temperature difference between the temperature at the inlet of the hot air 7 at the outlet of the air preheater of the hot air heater 4, the temperature at the inlet of the main high-temperature high-pressure extraction steam 17 of the hot air heater 4 and the temperature of the hot air 8 at the outlet of the hot air heater 4 The temperature difference between two adjacent cycles is also taken into account Thereby, the calculation result is more accurate and can better reflect the actual temperature stability coefficient of the hot air 8 at the outlet of the hot air heater 4.

[0097] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A system for increasing the temperature of hot air from a coal-fired boiler, characterized in that: The invention comprises a hot air heater (4), wherein the hot air heater (4) is arranged in a hot air duct at the outlet of an air preheater (5), the outlet end of the hot air heater (4) is communicated with a boiler (1), the hot air heater (4) is connected to a high-pressure cylinder (2) of a steam turbine via a hot air heater heat source pipeline, the high-pressure cylinder (2) of the steam turbine is used to provide a heat source to the hot air heater (4) via the hot air heater heat source pipeline, and a fan (6) is provided at a cold air duct at the inlet of the air preheater (5); An air filter assembly (18) is provided between the air preheater (5) and the fan (6), and the air filter assembly (18) is used to filter the cold air (13); The air filter assembly (18) comprises: A filter assembly housing (180), wherein a cold air inlet chamber (1800) and a cold air buffer chamber (1801) are provided in the filter assembly housing (180), wherein the cold air (13) enters the cold air buffer chamber (1801) through the cold air inlet chamber (1800), is filtered, and is then discharged to the air preheater (5) through the cold air buffer chamber (1801); A filter screen (1802), wherein the filter screen (1802) is fixedly connected to the cold air buffer chamber (1801); A gate plate (1803), the gate plate (1803) is connected to the cold air inlet chamber (1800) by sliding up and down, a sliding rod (1804) is fixedly connected to the gate plate (1803), the sliding rod (1804) is connected to the filter screen (1802) by sliding up and down, a buffer elastic member (1805) is sleeved on the sliding rod (1804), one end of the buffer elastic member (1805) is fixedly connected to the filter screen (1802), and the other end of the buffer elastic member (1805) is fixedly connected to the gate plate (1803); Two symmetrically arranged arc-shaped electromagnets (1806), the arc-shaped electromagnets (1806) being fixedly connected in the cold air buffer chamber (1801); A rotating wheel (1807), a rotating shaft (1808) is fixedly connected to the rotating wheel (1807), the rotating shaft (1808) is rotatably connected to the cold air buffer chamber (1801), a rotating driving member is provided on the rotating shaft (1808), and the rotating driving member is used to drive the rotating shaft (1808) to rotate, a wire (181) is provided on the hub (1809) of the rotating wheel (1807), a first conductive disk (1811) is provided on one end face of the rotating wheel (1807), the first conductive disk (1811) is electrically connected to the wire (181), a second conductive disk (1812) is fixedly connected to the inner wall of the cold air buffer chamber (1801), and the first conductive disk (1811) is in contact with the second conductive disk (1812); A heating lamp body (1810), wherein the heating lamp body (1810) is fixedly connected in the cold air buffer chamber (1801), and the heating lamp body (1810) is electrically connected to the second conductive disk (1812).

2. A system for increasing the hot air temperature of a coal-fired boiler according to claim 1, characterized in that: The fan (6) is used to pressurize the cold air (13) and then press it into the air preheater (5). The cold air (13) is heated in the air preheater (5) and becomes hot air (7) at the air preheater outlet. The heat source of the temperature rise of the cold air (13) comes from the hot flue gas (11). The hot flue gas (11) releases heat in the air preheater (5) and then cools down to become cold flue gas (12). The hot air (7) at the air preheater outlet is heated again in the hot air heater (4) and becomes hot air (8) at the hot air heater outlet.

3. The system for increasing the hot air temperature of a coal-fired boiler according to claim 1, characterized in that: The hot air heater heat source pipeline is provided with a steam turbine high-pressure cylinder (2), a hot air heater (4), a steam turbine extraction heater (10) and a regulating valve (15); The high-temperature high-pressure extraction steam (3) of the high-pressure cylinder (2) of the steam turbine is divided into main high-temperature high-pressure extraction steam (17) and bypass high-temperature high-pressure extraction steam (14). The main high-temperature high-pressure extraction steam (17) enters the hot air heater (4) to heat the hot air (7) at the outlet of the air preheater (5). The main high-temperature high-pressure extraction steam (17) is cooled in the hot air heater (4) and becomes hot air heater exhaust steam (9). The bypass high-temperature high-pressure extraction steam (14) is mixed with the hot air heater exhaust steam (9) to become high-pressure feed steam (16). The high-pressure feed steam (16) is sent to the steam turbine extraction heater (10). A regulating valve (15) is installed on the bypass high-temperature high-pressure steam extraction (14) pipeline. The regulating valve (15) is used to adjust the flow distribution of the main high-temperature high-pressure steam extraction (17) and the bypass high-temperature high-pressure steam extraction (14), thereby achieving the purpose of regulating the hot air (8) at the outlet of the hot air heater.

4. The system for increasing the hot air temperature of a coal-fired boiler according to claim 1, characterized in that: A combustion-supporting gas adding component (19) is provided between the hot air heater (4) and the boiler (1), and the combustion-supporting gas adding component (19) is used to add combustion-supporting gas into the boiler (1).

5. The system for increasing the hot air temperature of a coal-fired boiler according to claim 4, characterized in that: The combustion-supporting gas includes any one or more of oxygen, ozone and fluorine.

6. The system for increasing the hot air temperature of a coal-fired boiler according to claim 3, characterized in that: The hot air heater (4) is provided with a hot air heater outlet hot air monitoring system, which is electrically connected to a regulating valve (15). The hot air heater outlet hot air monitoring system is used to monitor the working state of the hot air heater (4) and adjust the regulating valve (15) when the working state of the hot air heater (4) is not good, thereby adjusting the flow distribution of the main high-temperature high-pressure steam extraction (17) and the bypass high-temperature high-pressure steam extraction (14), thereby achieving the purpose of regulating the hot air (8) at the hot air heater outlet.

7. The system for increasing the hot air temperature of a coal-fired boiler according to claim 6, characterized in that: The hot air monitoring system at the outlet of the hot air heater includes: a first temperature sensor, the first temperature sensor being arranged at the hot air inlet (7) at the air preheater outlet of the hot air heater (4) and being used to detect the temperature at the hot air inlet (7) at the air preheater outlet of the hot air heater (4); a second temperature sensor, the second temperature sensor being arranged at the inlet of the main high-temperature high-pressure extraction steam (17) of the hot air heater (4) and being used to detect the temperature at the inlet of the main high-temperature high-pressure extraction steam (17) of the hot air heater (4); a third temperature sensor, the third temperature sensor being arranged at the outlet of the hot air heater (8) of the hot air heater (4) and being used for detecting the temperature of the hot air (8) at the outlet of the hot air heater (8) of the hot air heater (4); a first flow rate sensor, the first flow rate sensor being arranged at the inlet of the hot air (7) at the outlet of the air preheater of the hot air heater (4), and being used for detecting the flow rate of the hot air (7) at the inlet of the hot air (7) at the outlet of the air preheater of the hot air heater (4); a second flow rate sensor, the second flow rate sensor being arranged at the inlet of the main high-temperature high-pressure extraction steam (17) of the hot air heater (4) and being used for detecting the flow rate of the hot air (7) at the outlet of the air preheater at the inlet of the main high-temperature high-pressure extraction steam (17) of the hot air heater (4); a third flow rate sensor, the third flow rate sensor being arranged at the outlet of the hot air heater (8) of the hot air heater (4) and being used for detecting the flow rate of the hot air (8) at the outlet of the hot air heater (8) of the hot air heater (4); a volume flow sensor, the volume flow sensor being arranged at a hot air heater outlet hot air (8) outlet of the hot air heater (4) and being used to detect the volume flow of the hot air heater outlet hot air (8) at the hot air heater outlet hot air (8) outlet of the hot air heater (4); a wind force sensor, the wind force sensor being arranged at the outlet of the hot air heater (8) of the hot air heater (4) and being used for detecting the wind force of the hot air (8) at the outlet of the hot air heater (8) of the hot air heater (4); A controller is provided, wherein the controller is electrically connected to the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow velocity sensor, the second flow velocity sensor, the third flow velocity sensor, the volume flow sensor, the wind sensor, and the regulating valve (15). The controller controls the regulating valve (15) to operate based on the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow velocity sensor, the second flow velocity sensor, the third flow velocity sensor, the volume flow sensor, and the wind sensor, and comprises the following steps: Step 1: Based on the first temperature sensor, the second temperature sensor, the third temperature sensor, the first flow rate sensor, the second flow rate sensor, the third flow rate sensor, the volume flow sensor and the wind force sensor, calculate the actual temperature stability coefficient of the hot air (8) at the outlet of the hot air heater (4): in, is the actual temperature stability coefficient of the hot air (8) at the outlet of the hot air heater (4), a is the error coefficient of the detection value of the volume flow sensor, Q v is the detection value of the volume flow sensor, Q m0 is the preset mass flow rate of the hot air (8) at the outlet of the hot air heater (4), g is the acceleration of gravity, which is 9.81, θ1 is the detection value of the first flow velocity sensor, θ2 is the detection value of the second flow velocity sensor, θ3 is the detection value of the third flow velocity sensor, N re is the detection value of the wind sensor, t is the detection cycle of the hot air monitoring system at the outlet of the hot air heater, A 1i A is the opening area at the hot air inlet (7) of the air preheater outlet of the hot air heater (4), 2i A is the opening area at the inlet of the main high-temperature high-pressure extraction steam (17) of the hot air heater (4), o is the opening area at the outlet of the hot air heater (8) of the hot air heater (4), T0 is the preset temperature of the hot air heater (8) at the outlet of the hot air heater (4), T 1a is the detection value of the first temperature sensor in the ath detection cycle, T 2a is the detection value of the second temperature sensor in the ath detection cycle, T 3a is the detection value of the third temperature sensor in the ath detection cycle, T 1(a+1) is the detection value of the first temperature sensor in the a+1th detection cycle, T 2(a+1) is the detection value of the second temperature sensor in the a+1th detection cycle, T 3(a+1) is the detection value of the third temperature sensor in the a+1th detection cycle, and x represents the total number of cycles of the hot air monitoring system at the hot air heater outlet; Step 2: The controller compares the actual temperature stability coefficient of the hot air (8) at the outlet of the hot air heater (4) with the preset temperature stability coefficient range of the hot air (8) at the outlet of the hot air heater (4). If the actual temperature stability coefficient of the hot air (8) at the outlet of the hot air heater (4) exceeds the preset temperature stability coefficient range of the hot air (8) at the outlet of the hot air heater (4), the controller adjusts the regulating valve (15), thereby adjusting the flow distribution of the main high-temperature high-pressure extraction steam (17) and the bypass high-temperature high-pressure extraction steam (14), so that the actual temperature stability coefficient of the hot air (8) at the outlet of the hot air heater (4) falls within the preset temperature stability coefficient range of the hot air (8) at the outlet of the hot air heater (4).

8. A method for increasing the temperature of hot air from a coal-fired boiler, for achieving the purpose of increasing the temperature of hot air from a coal-fired boiler by using the system for increasing the temperature of hot air from a coal-fired boiler according to any one of claims 1 to 7, characterized in that: The following steps are involved: The cold air (13) enters the air preheater (5) to absorb heat and heat up, becoming hot air (7) at the outlet of the air preheater. The hot air (7) at the outlet of the air preheater is heated again at the hot air heater (4) to become hot air (8) at the outlet of the hot air heater. The hot air (8) at the outlet of the hot air heater is sent to the boiler (1) to participate in combustion. The heat source of the hot air heater (4) comes from the high-pressure cylinder (2) of the steam turbine.

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