Solar auxiliary heating coal mill inlet hot primary air system and method

Abstract

The embodiment of the invention provides a solar auxiliary heating coal mill inlet hot primary air system and method. The system comprises a solar heat absorption assembly, a fused salt conveying assembly, a heat exchanger and a hot primary air pipeline. The heat exchanger is provided with a fused salt inlet, an air inlet and an air outlet, the hot primary air pipeline is communicated with the air outlet, and the fused salt conveying assembly is communicated with the fused salt inlet of the heat exchanger; wherein the solar heat absorption assembly is used for heating cold fused salt in the fused salt conveying assembly, the heat exchanger is configured to conduct heat exchange on hot fused salt in the fused salt conveying assembly and cold air introduced from the air inlet, and hot air obtained after heat exchange is introduced into an inlet of a coal mill through a hot primary air pipeline. In the invention, the solar energy technology is combined with the coal mill system and the like, and the hot primary air at the inlet of the coal mill is heated in an auxiliary manner by utilizing the solar energy, so that the temperature of the primary air can be effectively improved, the dependence on traditional energy can be reduced, and obvious energy-saving and environment-friendly benefits are achieved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure belong to the technical field of coal mills, and particularly relate to a solar-assisted heating coal mill inlet hot primary air system and method. BACKGROUND

[0002] With the global emphasis on clean energy and its application, solar energy as a renewable and pollution-free energy source is continuously expanding its use. In coal-fired power plants, the operating efficiency and energy consumption of the coal mill is one of the key factors affecting the overall performance of the power plant. The inlet primary air temperature of the coal mill has a direct impact on the drying and conveying effect of the coal powder, and thus affects the output and coal quality of the coal mill. However, the traditional primary air heating method of the coal mill mainly relies on the air preheater, which has certain limitations, such as low heating efficiency, high energy consumption, and the like.

[0003] Therefore, how to effectively improve the temperature of the primary air, reduce the dependence on traditional energy sources, and reduce the problem of low-temperature corrosion of the air preheater has become a technical problem to be solved by those skilled in the art. SUMMARY

[0004] Embodiments of the present disclosure aim to at least solve one of the technical problems existing in the prior art, and provide a solar-assisted heating coal mill inlet hot primary air system and method.

[0005] In a first aspect, the present disclosure provides a solar-assisted heating coal mill inlet hot primary air system, comprising: a solar heat absorption assembly, a molten salt conveying assembly, a heat exchanger, and a hot primary air pipeline.

[0006] The heat exchanger has a molten salt inlet, an air inlet, and an air outlet, the hot primary air pipeline is in communication with the air outlet, and the molten salt conveying assembly is in communication with the molten salt inlet of the heat exchanger.

[0007] The solar heat absorption assembly is configured to heat the cold molten salt in the molten salt conveying assembly, the heat exchanger is configured to exchange heat between the hot molten salt in the molten salt conveying assembly and the cold air introduced through the air inlet, and the hot air after heat exchange is introduced into the coal mill inlet through the hot primary air pipeline.

[0008] Optionally, the solar heat absorption assembly comprises a solar heat absorption tower, a solar heat absorber connected to the solar heat absorption tower, and a reflector for reflecting sunlight to the solar heat absorber.

[0009] Optionally, the molten salt conveying assembly comprises a hot molten salt pipeline connected between the hot salt outlet of the solar heat absorption assembly and the molten salt inlet of the heat exchanger, and a hot salt tank and a hot salt conveying pump arranged in the hot molten salt pipeline.

[0010] Optionally, along the hot molten salt flow direction, the hot salt delivery pump is arranged downstream of the hot salt tank.

[0011] Optionally, the heat exchanger is further provided with a molten salt outlet in communication with the molten salt inlet.

[0012] The molten salt delivery assembly comprises a cold molten salt pipeline connected between the cold salt inlet of the solar heat absorption assembly and the molten salt outlet of the heat exchanger, and a cold salt tank and a cold salt delivery pump arranged in the cold molten salt pipeline.

[0013] Optionally, along the cold molten salt flow direction, the cold salt delivery pump is arranged upstream of the cold salt tank.

[0014] Further, the system further comprises:

[0015] An air preheater, which is arranged in the hot primary air pipeline.

[0016] An auxiliary heating valve, which is arranged in the hot primary air pipeline.

[0017] Further, the system further comprises:

[0018] A warm air bypass, one end of which is in communication with the gas outlet of the heat exchanger, and the other end of which is in communication with the hot primary air pipeline.

[0019] A warm air valve, which is arranged in the warm air bypass.

[0020] Further, the system further comprises:

[0021] A primary air fan, which is in communication with the gas inlet of the heat exchanger through a pipeline.

[0022] A second aspect of the embodiments of the present disclosure provides a method for solar auxiliary heating of the primary air at the inlet of the coal mill, which is realized according to the above-mentioned system, and comprises the following steps:

[0023] Pumping the cold molten salt in the cold salt tank to the solar heat absorber by the cold salt delivery pump;

[0024] Reflecting the sunlight to the solar heat absorber by the reflector, so as to heat the cold molten salt in the solar heat absorber, and store the generated hot molten salt in the hot salt tank;

[0025] Pumping the hot molten salt in the hot salt tank to the heat exchanger by the hot salt delivery pump;

[0026] The primary air fan draws the cold air into the gas inlet of the heat exchanger, and exchanges heat with the hot molten salt in the heat exchanger pipeline, and the generated auxiliary hot air is introduced into the primary air pipeline through the gas outlet of the heat exchanger.

[0027] The auxiliary heating valve is opened, the auxiliary hot air enters the air preheater and mixes with the conventional hot air, and the mixed hot primary air is transported to the coal mill inlet.

[0028] The beneficial effects of embodiments of the present disclosure include:

[0029] In the present application, the solar technology is combined with the coal mill system, etc., and the solar energy is used to assist in heating the hot primary air at the coal mill inlet, which not only effectively increases the temperature of the primary air, but also reduces the dependence on traditional energy, and has significant energy-saving and environmental protection benefits. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 FIG. 1 is a structural schematic diagram of a solar energy assisted heating hot primary air system at a coal mill inlet according to an embodiment of the present disclosure;

[0031] Figure 2 FIG. 2 is a flow schematic diagram of a solar energy assisted heating hot primary air method according to another embodiment of the present disclosure.

[0032] In the drawings, 1 is a coal mill, 2 is a hot primary air pipeline, 3 is a solar heat absorption tower, 4 is a solar heat absorber, 5 is a reflector, 6 is a cold molten salt pipeline, 7 is a hot molten salt pipeline, 8 is a hot salt tank, 9 is a cold salt tank, 10 is a cold salt delivery pump, 11 is a hot salt delivery pump, 12 is an auxiliary heating valve, 13 is a heat exchanger, 14 is a primary air fan, 15 is a cold primary air outlet pipeline, 16 is an air preheater, and 17 is a warm air valve. DETAILED DESCRIPTION

[0033] In order for those skilled in the art to better understand the technical solutions of the present disclosure, the present disclosure will be further described in detail below in combination with the drawings and specific embodiments.

[0034] The embodiments of the present application will be further described in detail below in combination with the drawings and embodiments. The detailed description and drawings of the following embodiments are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described embodiments. In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is two or more; the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0035] In the description of the present application, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection" should be understood in a broad sense, for example, can be fixedly connected, can also be detachably connected, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0036] As shown in the drawings, Figure 1 A solar energy auxiliary heating coal mill inlet hot primary air system comprises a solar energy heat absorption assembly, a molten salt conveying assembly, a heat exchanger 13 and a hot primary air pipeline 2.

[0037] The heat exchanger 13 has a molten salt inlet, an air inlet and an air outlet, the hot primary air pipeline 2 is in communication with the air outlet, and the molten salt conveying assembly is in communication with the molten salt inlet of the heat exchanger 13.

[0038] The solar energy heat absorption assembly is used for heating cold molten salt in the molten salt conveying assembly, the heat exchanger 13 is configured to exchange heat between hot molten salt in the molten salt conveying assembly and cold air introduced from the air inlet, and the heat-exchanged hot air is introduced into the coal mill 1 inlet through the hot primary air pipeline 2.

[0039] In the present application, the solar energy technology is combined with the coal mill system and the like, and the solar energy is used to assist in heating the hot primary air at the coal mill inlet, which not only can effectively improve the temperature of the primary air, but also can reduce the dependence on traditional energy, and has significant energy-saving and environmental protection benefits.

[0040] In some embodiments, the heat exchanger 13 comprises a molten salt-air heater.

[0041] In some embodiments, the solar energy heat absorption assembly comprises a solar energy heat absorption tower 3, a solar energy heat absorber 4 connected to the solar energy heat absorption tower 3, and a reflector 5 for reflecting sunlight to the solar energy heat absorber 4. Specifically, the solar energy heat absorber 4 is arranged at the top of the solar energy heat absorption tower 3.

[0042] In some embodiments, the molten salt conveying assembly comprises a hot molten salt pipeline 7 connected between a hot salt outlet of the solar energy heat absorption assembly and a molten salt inlet of the heat exchanger 13, and a hot salt tank 8 and a hot salt conveying pump 11 arranged in the hot molten salt pipeline 7.

[0043] Specifically, the hot molten salt pipeline 7 is partially arranged in the solar energy heat absorption tower 3 and is in communication with the hot salt outlet of the solar energy heat absorber 4 at the top of the solar energy heat absorption tower 3.

[0044] In some embodiments, along the flow direction of the hot molten salt, the hot salt conveying pump 11 is arranged downstream of the hot salt tank 8.

[0045] In some embodiments, the heat exchanger 13 is further provided with a molten salt outlet communicating with the molten salt inlet.

[0046] The molten salt delivery assembly comprises a cold molten salt pipeline 6 connected between the cold salt inlet of the solar heat absorption assembly and the molten salt outlet of the heat exchanger 13, and a cold salt tank 9 and a cold salt delivery pump 10 arranged in the cold molten salt pipeline 6.

[0047] Specifically, the cold molten salt pipeline 6 is partially arranged in the solar heat absorption tower 3 and communicates with the cold salt inlet of the solar heat absorber 4 at the top of the solar heat absorption tower 3.

[0048] In some embodiments, the cold salt delivery pump 10 is arranged upstream of the cold salt tank 9 along the flow direction of the cold molten salt.

[0049] In some embodiments, the system further comprises an air preheater 16 arranged in the hot primary air pipeline 2 and an auxiliary heating valve 12 arranged in the hot primary air pipeline 2.

[0050] In some embodiments, the system further comprises a warm air bypass and a warm air valve 17, one end of the warm air bypass communicating with the gas outlet of the heat exchanger 13 and the other end communicating with the hot primary air pipeline 2, and the warm air valve 17 being arranged in the warm air bypass.

[0051] In some embodiments, the system further comprises a primary air fan 14 communicating with the gas inlet of the heat exchanger 13 through a pipeline.

[0052] Embodiment one

[0053] Auxiliary heating mode:

[0054] As Figure 1As shown, sunlight is reflected by the mirror 5 to the surface of the solar heat absorber 4 at the top of the solar heat absorption tower 3, the cold molten salt is pumped by the cold molten salt pump 10 through the cold molten salt pipeline 6 into the solar heat absorber 4 to absorb solar heat, and then the heated hot molten salt is sent to the hot salt tank 8 through the hot molten salt pipeline 7, when auxiliary heating is needed, the hot molten salt in the hot salt tank 8 is pumped by the hot molten salt pump 11 to the shell side inlet of the heat exchanger 13 (molten salt-air heater), the air enters the primary air fan 14 after being pressurized, and the cold air is sent to the air inlet of the heat exchanger 13 through the cold primary air outlet pipeline 15, the cold air is heated in the heat exchanger 13, and the hot molten salt is discharged from the molten salt outlet of the heat exchanger 13 and pumped to the cold salt tank 9 by the cold molten salt pump 10 for continuous circulation. The cold air is heated by the air outlet of the heat exchanger 13 to become auxiliary hot air, at this time the auxiliary heating valve 12 is opened, the auxiliary hot air enters the air preheater 16 and mixes with the air from the conventional source to form hot primary air, and enters the mill inlet hot primary air pipeline 2 and is further sent to the mill 1 to participate in the subsequent working process. Compared with the original system, the temperature of the mill inlet hot primary air is increased after the solar auxiliary heating system of the application is added, and the temperature increase can be adjusted by controlling the opening degree of the auxiliary heating valve 12 to avoid overheating of the mill inlet hot primary air. The cold salt tank 9 and the hot salt tank 8 are also used to store excess solar heat to provide heat continuously to realize the auxiliary heating function when the light condition is poor or at night.

[0055] Embodiment two

[0056] Flue heating mode:

[0057] In order to better heat the primary air, the air needs to be sent to the air preheater 16 installed at the tail of the boiler to be heated during normal operation of the boiler, and then the heated hot primary air is sent to the mill 1 to meet the requirements of mill start-up. When the boiler is cold, a large oil gun is needed for ignition and heating. In order to reduce the use of fuel, a heater needs to be installed in the mill inlet flue. This scheme has high construction difficulty and the risk of flue burning. Continue to refer to Figure 1, the sunlight is reflected by the mirror 5 to the surface of the solar heat absorber 4 at the top of the solar heat absorption tower 3, the cold molten salt is pumped into the solar heat absorber 4 by the cold molten salt conveying pump 10 to absorb solar heat, and then the heated hot molten salt is sent to the hot salt tank 8 through the hot molten salt pipeline 7; when auxiliary heating is needed, the hot molten salt in the hot salt tank 8 is pumped to the molten salt inlet of the heat exchanger 13 by the hot molten salt conveying pump 11, the cold air enters the primary air fan 14 after being pressurized, and then the cold air is sent to the air inlet of the heat exchanger 13 through the cold primary air outlet pipeline 15; the cold air is heated in the heat exchanger 13 to absorb the heat of the hot molten salt, and then the hot molten salt is discharged from the molten salt outlet of the heat exchanger 13, pumped to the cold salt tank 9 by the cold molten salt conveying pump 10, and continues to circulate. The cold air is heated to become auxiliary hot air, and the auxiliary heating valve 12 is closed at this time, and the auxiliary hot air directly enters the hot primary air pipeline 2 of the coal mill inlet through the warm air bypass provided with the warm air valve 17, and is further conveyed to the coal mill 1 to participate in the warm air duct process. Compared with the original system, the warm air bypass and the warm air valve 17 are added, which can avoid the direct contact of the flame generated by the heater arranged in the primary air duct of the conventional coal mill inlet with the air duct, thereby enhancing the safety. At the same time, the opening degree of the warm air valve 17 can be controlled to adjust the temperature of the warm air. The cold salt tank 9 and the hot salt tank 8 can also store excess solar heat, and can provide heat continuously to realize the cold start function of the warm air duct when the light condition is poor or at night.

[0058] Reference Figure 2 In a second aspect of the embodiments of the present disclosure, a solar auxiliary heating coal mill inlet hot primary air method is provided, and the method is realized according to the above-mentioned system, which comprises the following steps.

[0059] S101, the cold molten salt in the cold salt tank 9 is pumped to the solar heat absorber 4 by the cold molten salt conveying pump 10.

[0060] S102, the sunlight is reflected to the solar heat absorber 4 by the mirror 5 to heat the cold molten salt in the solar heat absorber 4, and the hot molten salt generated by heating is stored in the hot salt tank 8.

[0061] S103, the hot molten salt in the hot salt tank 8 is pumped to the heat exchanger 13 by starting the hot molten salt conveying pump 11.

[0062] S104, the cold air is extracted by the primary air fan 14 and enters the air inlet of the heat exchanger 13, and the cold air exchanges heat with the hot molten salt in the heat exchanger 13, and the auxiliary hot air formed by the heat exchange enters the primary air pipeline through the air outlet of the heat exchanger 13.

[0063] S105, the auxiliary heating valve 12 is opened, the auxiliary hot air enters the air preheater 16 to mix with the conventional hot air, and the mixed hot primary air is conveyed to the inlet of the coal mill 1.

[0064] It is to be understood that the above-mentioned embodiments are merely illustrative of the principles of the present disclosure and that numerous modifications and improvements can be effected thereto without departing from the spirit and scope of the disclosure.

Claims

1. A solar assisted heating coal mill inlet hot primary air system characterized by, The solar heat absorption assembly, the molten salt conveying assembly, the heat exchanger and the hot primary air pipeline; The heat exchanger has a molten salt inlet, an air inlet and an air outlet, the hot primary air pipeline is communicated with the air outlet, and the molten salt conveying assembly is communicated with the molten salt inlet of the heat exchanger; The solar heat absorption assembly is used for heating cold molten salt in the molten salt conveying assembly, the heat exchanger is configured to exchange heat between hot molten salt in the molten salt conveying assembly and cold air introduced from the air inlet, and the hot air after heat exchange is introduced into the inlet of the coal mill through the hot primary air pipeline.

2. The system of claim 1, wherein, The solar heat absorption assembly comprises a solar heat absorption tower, a solar heat absorber connected with the solar heat absorption tower, and a reflector for reflecting sunlight to the solar heat absorber.

3. The system of claim 1, wherein, The molten salt conveying assembly comprises a hot molten salt pipeline connected between the hot salt outlet of the solar heat absorption assembly and the molten salt inlet of the heat exchanger, and a hot salt tank and a hot salt conveying pump arranged in the hot molten salt pipeline.

4. The system of claim 3, wherein, The hot salt conveying pump is arranged downstream of the hot salt tank along the hot molten salt flow direction.

5. The system of claim 1, wherein, The heat exchanger is further provided with a molten salt outlet communicated with the molten salt inlet; The molten salt conveying assembly comprises a cold molten salt pipeline connected between the cold salt inlet of the solar heat absorption assembly and the molten salt outlet of the heat exchanger, and a cold salt tank and a cold salt conveying pump arranged in the cold molten salt pipeline.

6. The system of claim 5, wherein, The cold salt conveying pump is arranged upstream of the cold salt tank along the cold molten salt flow direction.

7. The system of claim 1, wherein, Further comprising: An air preheater arranged in the hot primary air pipeline; An auxiliary heating valve arranged in the hot primary air pipeline.

8. The system of claim 1, wherein, Further comprising: A warm air bypass, one end of which is communicated with the air outlet of the heat exchanger, and the other end of which is communicated with the hot primary air pipeline; A warm air valve arranged in the warm air bypass.

9. The system of claim 1, wherein, Further comprising: A primary air fan communicated with the air inlet of the heat exchanger through a pipeline.

10. A solar assisted heating of mill inlet hot primary air method, implemented according to the system of any one of claims 1-9, characterized in that, Comprising: The cold molten salt in the cold salt tank is pumped to the solar heat absorber by the cold salt conveying pump; The sunlight is reflected to the solar heat absorber by the reflector to heat the cold molten salt in the solar heat absorber, and the hot molten salt generated by heating is stored in the hot salt tank; The hot molten salt in the hot salt tank is pumped to the heat exchanger by starting the hot salt conveying pump; The primary air fan extracts cold air and introduces the cold air into the air inlet of the heat exchanger, and exchanges heat with the hot molten salt in the heat exchanger pipeline, and the auxiliary hot air formed is introduced into the primary air pipeline through the air outlet of the heat exchanger; The auxiliary heating valve is opened, so that the auxiliary hot air enters the air preheater and mixes with the conventional hot air, and the mixed hot primary air is conveyed to the inlet of the coal mill.

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