Coal-fired generator set and power generation method thereof

Abstract

The present invention discloses a coal-fired generator set and a method for generating electricity thereof, belonging to the technical field of boiler combustion, comprising: a feeding unit including a mounting base, a pulverized coal burner arranged on the mounting base, and an ejector arranged on a side of the mounting base away from the pulverized coal burner; a combustion unit including a boiler connected to the ejector and a high-temperature flue connected to the boiler; and a reflux unit including a heat exchanger arranged on the high-temperature flue and a reflux arranged on the heat exchanger. The coal-fired generator set and the method for generating electricity thereof help pulverized coal to be rapidly gasified and enter the boiler by providing an ejector. The ignition point of the gasified gas is significantly lower than that of existing pulverized coal, which is conducive to forming a stable combustion torch and providing strong support for the combustion of the entire boiler. At the same time, the energy of the high-temperature flue gas generated by the boiler is also recovered, thereby realizing energy recycling and avoiding energy waste.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler combustion, and in particular to a coal-fired generator set and a power generation method thereof. Background Art

[0002] In recent years, my country's energy transition has accelerated. The large-scale integration of renewable energy sources into the grid will force coal-fired power generation, primarily a primary source of electricity, to fully participate in deep peak regulation. Faced with the need to absorb large-scale fluctuating power sources such as wind and solar power, coal-fired generators, as the ballast of the power generation sector, must undergo unit flexibility improvements to further expand their load regulation capabilities and achieve deep peak regulation. Currently, the minimum stable combustion load designed for most coal-fired units in China is 40% to 50%. To achieve deep peak regulation at 20% to 40% of rated output, unstable low-load combustion is a must-address issue.

[0003] In the actual operation of existing coal-fired power generation units, in order to ensure low-load combustion, the heat source energy provided by the burner is reduced, which often leads to unstable combustion inside the boiler and the waste of high-temperature flue gas generated during the combustion process.

[0004] Based on the above situation, it is necessary to provide a stable combustion technology that has strong adaptability to coal burning, does not add additional cost for combustion support, and does not require pulverized coal burner modification that may affect the safe operation of the boiler at full load, in order to solve the current problem of stable combustion at low load during deep peak regulation of coal-fired power generation units. Summary of the Invention

[0005] In view of the above-mentioned problems existing in the existing coal-fired power generation units, the present invention is proposed.

[0006] Therefore, the purpose of the present invention is to provide a coal-fired power generation unit, the purpose of which is to solve the problem of unstable combustion inside the boiler of existing coal-fired power generation units, which often occurs during actual operation in order to ensure low-load combustion and reduce the heat source energy provided by the burner.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0008] A feeding unit includes a mounting base, a pulverized coal burner disposed on the mounting base, and an ejector disposed on a side of the mounting base away from the pulverized coal burner;

[0009] A combustion unit comprising a boiler connected to the ejection portion and a high-temperature flue connected to the boiler; and

[0010] A reflux unit, comprising a heat exchanger disposed on the high-temperature flue, and a reflux portion disposed on the heat exchanger;

[0011] The heat exchanger surface includes an arcuate surface and a frustum surface symmetrical with respect to the arcuate surface.

[0012] As a preferred solution of the coal-fired power generation unit of the present invention, the ejection portion includes a boosting assembly arranged on a side of the mounting base away from the pulverized coal burner, and a drainage assembly arranged on the boosting assembly.

[0013] As a preferred solution of the coal-fired power generation unit of the present invention, the boosting assembly includes an air inlet pipe arranged on the side of the mounting base away from the pulverized coal burner, and an ejector head connected to the air inlet pipe.

[0014] As a preferred solution of the coal-fired power generation unit described in the present invention, the drainage assembly includes a diffuser connected to the end of the ejector head away from the air inlet pipe, a mixing tube connected to the end of the diffuser away from the ejector head, a drainage tube connected to the end of the mixing tube away from the diffusion tube, and a collecting tube arranged at the end of the drainage tube away from the mixing tube.

[0015] As a preferred solution of the coal-fired power generation unit of the present invention, the reflux part includes a connecting component arranged on the heat exchanger and an exchange component arranged inside the heat exchanger.

[0016] As a preferred solution of the coal-fired power generation unit of the present invention, wherein: the connecting assembly includes a return pipe connected between the heat exchanger and the ejector, and a combustion-supporting pipe connected between the heat exchanger and the pulverized coal burner;

[0017] The return pipe is connected to the arc surface of the heat exchanger shell.

[0018] As a preferred solution of the coal-fired power generation unit of the present invention, wherein: the exchange assembly includes a wing plate, a trapezoidal groove provided on the wing plate, and a guide hole provided on the wing plate;

[0019] At least two groups of wing plates are provided, and the wing plates are symmetrically arranged relative to the return pipe.

[0020] Another object of the present invention is to provide a power generation method for a coal-fired power generation unit, the purpose of which is to solve the technical problem that in the actual operation of existing coal-fired power generation units, in order to ensure low-load combustion, the heat source energy provided by the burner is reduced, resulting in unstable combustion inside the boiler and the high-temperature flue gas generated during the combustion process being wasted.

[0021] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising a coal-fired power generation unit, the method comprising:

[0022] The pulverized coal is ignited by the pulverized coal burner and enters the boiler for combustion;

[0023] The high-temperature flue gas generated by the combustion of the boiler enters the reflow unit through the high-temperature flue, and enters the pulverized coal burner again through the reflow unit to provide a heat source.

[0024] As a preferred solution of the power generation method of the coal-fired power generation unit of the present invention, when the pulverized coal burner is in operation, air simultaneously passes through the ejection portion into the boiler to be fully mixed with the pulverized coal.

[0025] As a preferred solution of the power generation method of the coal-fired power generation unit described in the present invention, the high-temperature flue gas generated by the combustion of the boiler enters the reflux unit through the high-temperature flue, and the impurities or solid particles therein pass through the reflux part and return to the boiler for further treatment.

[0026] The beneficial effects of the present invention are as follows: by setting up an ejection part, the ignited high-temperature air flow is used to eject the external air flow, so that the air flow quickly enters the ejection part and is fully mixed with the coal powder. At the same time, the high-temperature flue gas generated inside the boiler also enters the coal powder burner through the reflux part as a heat source, thereby helping the coal powder to be quickly gasified and enter the boiler. The ignition point of the gasified gas is much lower than that of the existing coal powder. Even under the conditions of very low unit load and a significant drop in furnace temperature, a stable combustion torch is formed at the outlet of the coal powder gasification burner, which has extremely strong support for the combustion of the entire boiler, thereby achieving the purpose of deep peak regulation of the coal-fired unit and improving the combustion stability of the boiler under low-load operation conditions. At the same time, the high-temperature flue gas energy generated by the boiler is also recovered, and there is no need to continuously provide a heat source to the coal powder burner, thereby realizing energy recycling and avoiding energy waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be derived from these drawings without inventive effort. Among them:

[0028] Figure 1 It is a schematic diagram of the overall structure of the coal-fired power generation unit of the present invention.

[0029] Figure 2 for Figure 1 Enlarged schematic diagram of point A in the middle.

[0030] Figure 3 It is a cross-sectional schematic diagram of the reflux unit of the coal-fired power generation unit of the present invention.

[0031] Figure 4This is a schematic diagram of the structure of the exchange component of the reflux unit of the coal-fired power generation unit of the present invention. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it constitute a separate or selective embodiment that is mutually exclusive with other embodiments.

[0035] Furthermore, the present invention is described in detail with reference to schematic diagrams. For ease of illustration, when describing the embodiments of the present invention, cross-sectional views illustrating device structures may be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, the three-dimensional dimensions of length, width, and depth should be included.

[0036] Example 1

[0037] Reference Figure 1-2 , which is a first embodiment of the present invention, provides a coal-fired power generation unit, which includes:

[0038] The feeding unit 100 includes a mounting base 101, a pulverized coal burner 102 disposed on the mounting base 101, and an ejection portion 103 disposed on a side of the mounting base 101 away from the pulverized coal burner 102; the combustion unit 200 includes a boiler 201 connected to the ejection portion 103, and a high-temperature flue 202 connected to the boiler 201; and the reflow unit 300 includes a heat exchanger 301 disposed on the high-temperature flue 202, and a reflow portion 302 disposed on the heat exchanger 301; the surface of the heat exchanger 301 It includes an arcuate surface K and a frustum surface M symmetrical with respect to the arcuate surface K. The pulverized coal is gasified in the pulverized coal burner 102 and enters the ejection part 103. The air collides with the gasified pulverized coal flow at a high acceleration through the ejection part 103, and enters the boiler 201 for combustion after being evenly mixed. The high-temperature flue gas generated by the combustion enters the pulverized coal burner 102 as a heat source through the reflux unit 300. At this time, the pulverized coal is gasified to a greater extent in a high-temperature and low-oxygen environment, and is evenly mixed with the air and then burned into the boiler 201, thereby improving the stability of the coal-fired unit.

[0039] Among them, the introduction part 103 includes a boosting component 103a arranged on the side of the mounting base 101 away from the pulverized coal burner 102, and a diversion component 103b arranged on the boosting component 103a. When the pulverized coal is burned and gasified, the high temperature reduces the pressure of the hot gas, thereby introducing the outside air into the introduction part 103 through the diversion component 103b. At the same time, the air has a greater pressure and power when passing through the boosting component 103a, which improves the degree of mixing between the air and the pulverized coal gas. Since the ignition point of the gasified gas is much lower than that of the existing pulverized coal, even under the conditions of very low unit load and a significant drop in furnace temperature, a stable combustion torch can be formed at the outlet of the pulverized coal gasification burner, which has extremely strong support for the combustion of the entire boiler 201, thereby achieving the purpose of deep peak regulation of the coal-fired unit and improving the combustion stability of the boiler 201 under low-load operation conditions.

[0040] During use, the pulverized coal enters the pulverized coal burner 102 and is ignited and vaporized. It is fully mixed with the air entering through the ejector section 103 to form a stable torch. The high-temperature gas generated by the combustion in the boiler 201 passes through the reflux section 302, and the impurities or solid particles therein are returned to the boiler 201 for further processing. The clean high-temperature low-oxygen gas enters the pulverized coal burner 102 as a heat source, causing a large amount of flammable volatile gas in the pulverized coal to precipitate and be sprayed into the furnace of the boiler 201 to assist combustion, thereby improving the combustion stability of the boiler 201, realizing energy recovery and utilization, and avoiding energy waste.

[0041] Example 2

[0042] Reference Figure 1-4, which is the second embodiment of the present invention. This embodiment differs from the first embodiment in that: the boosting component 103a includes an air intake pipe 103a-1 arranged on the side of the mounting base 101 away from the pulverized coal burner 102, and an ejector head 103a-2 connected to the air intake pipe 103a-1. After being pressurized by the ejector head 103a-2, the air enters the pulverized coal burner 102 through the air intake pipe 103a-1. At the same time, the ejector head 103a-2 effectively prevents the internal gas from escaping, thereby improving the safety of the device.

[0043] Compared with Example 1, the drainage assembly 103b further includes a diffusion tube 103b-1 connected to the end of the ejector head 103a-2 away from the air inlet pipe 103a-1, a mixing tube 103b-2 connected to the end of the diffusion tube 103b-1 away from the ejector head 103a-2, a drainage tube 103b-3 connected to the end of the mixing tube 103b-2 away from the diffusion tube 103b-1, and a collecting tube 103b-4 arranged at the end of the drainage tube 103b-3 away from the mixing tube 103b-2. The gas passes through the collecting pipe 103b-4 and is pressed into the collecting pipe 103b-4 by the atmospheric pressure due to the low air pressure caused by the high-temperature gas inside, and then enters the drainage pipe 103b-3 and the mixing pipe 103b-2. Due to the reduction in the diameter of the mixing pipe 103b-2, it has a greater flow rate, which in turn accelerates the collection pipe 103b-4 to capture the outside air. After the air with a higher flow rate enters the diffuser 103b-1, it enters the boost component 103a under the action of atmospheric pressure and the local pressure of the mixing pipe 103b-2.

[0044] Compared with Example 1, further, the reflux section 302 includes a connecting component 302a arranged on the heat exchanger 301, and an exchange component 302b arranged inside the heat exchanger 301. When the high-temperature flue gas generated by the boiler 201 passes through the reflux section 302, the solid particles such as impurities in the flue gas are refluxed to the boiler 201 through the connecting component 302a, and the clean high-temperature low-oxygen gas passes through the exchange component 302b and enters the pulverized coal burner 102 at a higher temperature as a heat source.

[0045] Compared with Example 1, the connection assembly 302a further includes a return pipe 302a-1 connected between the heat exchanger 301 and the ejection portion 103, and a combustion-supporting pipe 302a-2 connected between the heat exchanger 301 and the pulverized coal burner 102. After the high-temperature flue gas enters the heat exchanger 301 from bottom to top through the high-temperature flue 202, the impurities and other solid particles in the flue gas are returned to the boiler 201 for further processing through the return pipe 302a-1. The clean high-temperature flue gas then enters the pulverized coal burner 102 through the combustion-supporting pipe 302a-2 to be fully mixed with the pulverized coal and the like.

[0046] The return pipe 302a-1 is connected to the arc surface K of the outer shell of the heat exchanger 301. After the high-temperature flue gas enters the heat exchanger 301 from bottom to top through the high-temperature flue 202, it first passes through the frustum M with a larger upper part and a smaller lower part, and then passes through the arc surface K. Due to the increase in the cross-sectional diameter, the gas flow rate will decrease accordingly, thereby increasing the residence time of the high-temperature flue gas in the heat exchanger 301, so that the impurities and other solid particles in the high-temperature flue gas are removed more thoroughly.

[0047] Compared with Example 1, the exchange assembly 302b further includes a wing plate 302b-1, a trapezoidal groove 302b-2 provided on the wing plate 302b-1, and a guide hole 302b-3 provided on the wing plate 302b-1. When the high-temperature flue gas passes through the wing plate 302b-1, due to the design of the trapezoidal groove 302b-2 and the weight of solid particles such as impurities being greater than the weight of the gas, the pressure on the side of the trapezoidal groove 302b-2 with a shorter side is lower, making the solid shells such as impurities in the high-temperature flue gas have a greater tendency to flow toward the return pipe 302a-1, while the clean flue gas continues to move upward and enter the pulverized coal burner 102 through the combustion-supporting pipe 302a-2;

[0048] At least two groups of wing plates 302b-1 are provided, and the wing plates 302b-1 are symmetrically arranged relative to the return pipe 302a-1. The high-temperature flue gas is rectified when passing through the guide holes 302b-3 on the wing plates 302b-1. At the same time, there is almost no pressure difference in the longitudinal direction inside the heat exchanger 301 relative to the return pipe 302a-1, which helps to squeeze the solid particles such as impurities in the high-temperature flue gas into the return pipe 302a-1 in the horizontal direction due to the pressure difference measured by the trapezoidal groove 302b-2, and the high-temperature flue gas is more smoothly sucked into the combustion-supporting pipe 302a-2 due to its light weight and small momentum.

[0049] It is worth noting that the wing plate 302b-1 can be made of copper, titanium, nickel, aluminum, or alloys thereof.

[0050] The remaining structures are the same as those of Example 1.

[0051] Example 3

[0052] Reference Figure 1-4 , which is the third embodiment of the present invention, is based on embodiments 1-2 and provides a method for generating electricity from a coal-fired power generation unit. This embodiment differs from the second embodiment in that it includes:

[0053] The pulverized coal is ignited by the pulverized coal burner 102 and enters the boiler 201 for combustion;

[0054] The high-temperature flue gas generated by the combustion of the boiler 201 enters the reflow unit 300 through the high-temperature flue 202, and enters the pulverized coal burner 102 again through the reflow unit 300 to provide a heat source. The high-temperature flue gas has the characteristics of high temperature (900℃~1300℃), low flue gas content (3%~8%), and low pressure (-50Pa~-100Pa). This not only can obtain the gasification heat source at the lowest cost, shortest distance, and simplest structure, but the high-temperature flue gas with low oxygen concentration can also provide a good low-oxygen environment for the gasification process, improve the coal powder gasification effect, and reduce the proportion of carbon dioxide in the fuel gas. While obtaining a stable flame, energy reuse is achieved.

[0055] Compared with Example 2, further, when the pulverized coal burner 102 is working, the air enters the boiler 201 through the ejection part 103 at the same time and is fully mixed with the pulverized coal. When the boiler 201 is operating normally, the primary air pressure is about 6kPa~12kPa, the secondary air pressure is about 0.6kPa~1.5kPa, the temperatures of the primary air and the secondary air are both 250℃-330℃, and the high-temperature furnace smoke pressure is about -50Pa~-100Pa. Based on the pressure difference between the three, not only can the ejection power be guaranteed to be sufficient, but the working medium flow rate in the pulverized coal burner 102 can also be adjusted by the flow rate of the ejected air flow, so that the flow rate of the entire device is adjustable. Based on the temperature difference between the primary air and the secondary air and the high-temperature furnace smoke, the working medium flow rate in the pulverized coal gasification burner is adjusted by the flow rate of the ejected air flow, so that the temperature of the entire device is adjustable.

[0056] Compared with Example 2, further, the high-temperature flue gas generated by the combustion of the boiler 201 enters the reflux unit 300 through the high-temperature flue 202, and the impurities or solid particles therein are returned to the boiler 201 through the reflux part 302 for further treatment. The temperature range of the high-temperature flue gas can be flexibly selected within the range of 900°C to 1300°C, and there is no need to add a separate heat source for coal powder gasification, which greatly reduces the operating cost of the device; and the oxygen volume concentration of the high-temperature flue gas is below 10%, and the low-oxygen high-temperature flue gas provides the required low-oxygen conditions for the operation of the coal powder gasification burner, which can improve the gasification efficiency of the coal powder gasification burner.

[0057] The remaining structures are the same as those of Example 2.

[0058] It is important to note that the construction and arrangement of the present application shown in a number of different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape, and proportion of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, changes in orientation, etc.) without departing substantially from the novel teachings and advantages of the subject matter described in this application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of the element may be inverted or otherwise changed, and the nature, number, or position of the discrete elements may be altered or changed. Therefore, all such modifications are intended to be included within the scope of the present invention. The order or sequence of any process or method steps may be changed or reordered according to alternative embodiments. In the claims, any "means plus function" clause is intended to cover the structure described herein that performs the function, and is not only structurally equivalent but also equivalent structures. Other replacements, improvements, changes, and omissions may be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of the present invention. Therefore, the invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0059] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (i.e., those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0060] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A coal-fired power generation unit, characterized by: include, A feeding unit (100) comprises a mounting seat (101), a pulverized coal burner (102) arranged on the mounting seat (101), and an ejection portion (103) arranged on a side of the mounting seat (101) away from the pulverized coal burner (102); A combustion unit (200) comprises a boiler (201) connected to the ejection portion (103), and a high-temperature flue (202) connected to the boiler (201); and A reflux unit (300) comprising a heat exchanger (301) disposed on the high-temperature flue (202), and a reflux portion (302) disposed on the heat exchanger (301); The surface of the heat exchanger (301) includes a curved surface (K) and a frustum surface (M) symmetrical with respect to the curved surface (K); The ejection portion (103) comprises a boosting component (103a) arranged on a side of the mounting seat (101) away from the pulverized coal burner (102), and a drainage component (103b) arranged on the boosting component (103a); The reflux portion (302) comprises a connection component (302a) arranged on the heat exchanger (301), and an exchange component (302b) arranged inside the heat exchanger (301); The connecting assembly (302a) comprises a return pipe (302a-1) connected between the heat exchanger (301) and the ejection portion (103), and a combustion-supporting pipe (302a-2) connected between the heat exchanger (301) and the pulverized coal burner (102); The return pipe (302a-1) is connected to the arc-shaped surface (K) of the outer shell of the heat exchanger (301); The exchange component (302b) comprises a wing plate (302b-1), a trapezoidal groove (302b-2) provided on the wing plate (302b-1), and a guide hole (302b-3) provided on the wing plate (302b-1); At least two groups of the wing plates (302b-1) are provided, and the wing plates (302b-1) are symmetrically arranged relative to the return pipe (302a-1).

2. The coal-fired power generation unit according to claim 1, characterized in that: The boosting assembly (103a) comprises an air inlet pipe (103a-1) arranged on a side of the mounting seat (101) away from the pulverized coal burner (102), and an ejector head (103a-2) connected to the air inlet pipe (103a-1).

3. The coal-fired power generation unit according to claim 2, characterized in that: The drainage assembly (103b) comprises a diffusion tube (103b-1) connected to an end of the ejector head (103a-2) away from the air inlet pipe (103a-1), a mixing tube (103b-2) connected to an end of the diffusion tube (103b-1) away from the ejector head (103a-2), a drainage tube (103b-3) connected to an end of the mixing tube (103b-2) away from the diffusion tube (103b-1), and a collecting tube (103b-4) arranged at an end of the drainage tube (103b-3) away from the mixing tube (103b-2).

4. A method for generating electricity using a coal-fired power generation unit, characterized in that: The method comprises the coal-fired power generation unit according to any one of claims 1 to 3, comprising: Pulverized coal is ignited by the pulverized coal burner (102) and enters the boiler (201) for combustion; The high-temperature flue gas generated by combustion in the boiler (201) enters the reflow unit (300) through the high-temperature flue (202), and then enters the pulverized coal burner (102) again through the reflow unit (300) to provide a heat source.

5. The power generation method of a coal-fired power generation unit according to claim 4, characterized in that: When the pulverized coal burner (102) is in operation, air simultaneously passes through the ejector (103) and enters the boiler (201) to be fully mixed with the pulverized coal.

6. The power generation method of a coal-fired power generation unit according to claim 5, characterized in that: High-temperature flue gas generated by combustion in the boiler (201) enters the reflow unit (300) through the high-temperature flue (202), and impurities or solid particles in the flue gas pass through the reflow pipe (302a-1) and return to the boiler (201) for further processing.

Images