Hydrogen coal gasification combustion device and method

Abstract

This invention provides a hydrogen-fired pulverized coal gasification combustion device and method, relating to the field of power generation technology. The hydrogen burner of this invention acts as a rigid, high-temperature, and stable torch with a flame temperature reaching 1400–1500°C. Pulverized coal in the combustion chamber comes into contact with the hydrogen flame, causing the coal particles to be rapidly heated and volatilized, resulting in particle breakage and rapid ignition within the combustion chamber. After initial combustion, the coal-fired gas stream, along with the airflow from the ventilation duct, enters the gasification chamber. Under high-temperature, oxygen-deficient conditions, the coal generates combustible gases such as carbon monoxide and hydrogen, as well as activated semi-coke, which is then injected into the furnace, forming a gas-like combustion torch. This achieves the purpose of ignition and stable combustion at low loads in the pulverized coal boiler.

Description

Technical Field

[0001] This invention relates to the field of power generation technology, and in particular to a hydrogen-coal powder gasification and combustion device and method. Background Technology

[0002] With the continuous adjustment and deepening of the national energy structure, my country's installed capacity of renewable energy has increased year by year. Currently, clean power sources with seasonal and intermittent characteristics, such as hydropower and wind power, are developing rapidly. However, while renewable energy has continued to develop rapidly in recent years, some regions have experienced serious wind and solar power curtailment problems. For coal-fired power generating units themselves, in order to better adapt to the requirements of deep peak shaving and improve the safety and reliability of unit operation, necessary and more in-depth optimization and modification of the units are required. The first issues to pay attention to are stable combustion under low load and low flue gas temperature at the SCR inlet.

[0003] To further enhance the boiler's low-load stable combustion capability and achieve the goal of deep peak shaving to 15% of rated load under conventional coal quality, the current technologies adopted include plasma stable combustion retrofitting and micro-oil combustion technology retrofitting, supplemented by combustion device modification, hot primary air flue gas mixing retrofitting, hot primary air heater modification, and dynamic separator modification to improve low-load stable combustion characteristics.

[0004] Plasma ignition and stable combustion technology uses high-temperature plasma as an ignition source to achieve cold start-up and stable combustion at low loads in boilers. However, due to the limited energy of the plasma ignition source, this technology has high requirements for coal quality; fluctuations in coal quality can easily cause flame instability, necessitating the addition of oil for combustion assistance. Furthermore, plasma ignition technology suffers from arc interruption, short anode and cathode lifespan requiring periodic replacement, and low burnout rates with poor coal quality, necessitating frequent soot blowing in the air preheater. Micro-oil combustion technology uses a micro-oil gun as an ignition source to achieve cold start-up and stable combustion at low loads in boilers. Micro-oil ignition technology offers adjustable fuel output and wider coal adaptability than plasma ignition technology. However, the micro-oil ignition process suffers from incomplete oil combustion, posing significant safety hazards to equipment such as electrostatic precipitators.

[0005] To solve the above problems and achieve stable combustion under low boiler load conditions while meeting the unit's deep peak shaving requirements, a new type of combustion device needs to be developed. Summary of the Invention

[0006] In view of this, one of the objectives of the present invention is to provide a hydrogen-coal powder gasification combustion device to solve the technical problem of poor operation of combustion devices under ultra-low load conditions in the prior art.

[0007] The second objective of this invention is to provide a method for hydrogen-coal powder gasification and combustion.

[0008] To achieve one of the above objectives, the present invention provides a hydrogen-coal pulverized gasification and combustion device, comprising a coal pulverized combustion cylinder, a blower, and a gasification chamber. The gasification chamber is located at one end of the blower and is connected to the blower. The coal pulverized combustion cylinder is located in the inner cavity of the blower, with both its head and tail ends placed in the inner cavity of the blower. A hydrogen burner is inserted into the head end of the coal pulverized combustion cylinder.

[0009] Preferably, the pulverized coal combustion chamber includes at least one stage of pulverized coal combustion chamber, with each stage of the pulverized coal combustion chamber connected end to end, and the hydrogen burner inserted into the end of the pulverized coal combustion chamber.

[0010] Preferably, the diameter of the pulverized coal combustion cylinder gradually increases from the point closer to the hydrogen burner to the point farther away from the hydrogen burner.

[0011] Preferably, the pulverized coal combustion tube includes a primary pulverized coal combustion tube and a secondary pulverized coal combustion tube connected end to end, the secondary pulverized coal combustion tube and the primary pulverized coal combustion tube are connected, and the hydrogen burner is inserted into the primary pulverized coal combustion tube;

[0012] A pulverized coal concentration device for supplying pulverized coal to the pulverized coal combustion cylinder is installed at the end of the primary pulverized coal combustion cylinder.

[0013] Preferably, the air duct includes a primary air duct and a secondary air duct, the secondary air duct is sleeved outside the primary air duct, both the primary air duct and the secondary air duct are connected to the gasification chamber, and both the primary pulverized coal combustion chamber and the secondary pulverized coal combustion chamber are placed inside the cavity of the primary air duct.

[0014] Preferably, the end of the primary air duct is provided with an elbow.

[0015] Preferably, a secondary air cyclone separator is provided between the inner wall of the secondary air duct and the outer wall of the primary air duct.

[0016] Preferably, the end of the primary air duct facing the gasification chamber is provided with a flame stabilizing ring.

[0017] Preferably, the vaporization chamber is provided with a wall, and a wall-mounted air chamber is formed between the wall and the inner wall of the vaporization chamber. The wall is provided with a plurality of air ducts, and the air ducts connect the wall-mounted air chamber and the hollow inner cavity of the vaporization chamber.

[0018] To achieve the second objective mentioned above, the present invention provides a combustion method using any of the hydrogen-coal pulverized gasification combustion devices described above, comprising the following steps:

[0019] The hydrogen burner provides a high-temperature hydrogen flame to ignite the pulverized coal, forming a high-temperature pulverized coal flame.

[0020] After the high-temperature pulverized coal flame mixes with the air, it enters the gasification chamber. The pulverized coal particles in the high-temperature pulverized coal flame generate high-temperature reactive gases under the action of hydrogen in the oxygen-deficient reducing atmosphere.

[0021] High-temperature reactive gases are injected into the furnace as fuel for combustion.

[0022] The hydrogen-coal powder gasification and combustion apparatus and method provided by this invention have the following technical advantages:

[0023] This hydrogen-fired pulverized coal gasification and combustion device mainly consists of a pulverized coal combustion cylinder, a blower, a gasification chamber, and a hydrogen burner. The gasification chamber is located at one end of the blower and is connected to the blower. The pulverized coal combustion cylinder is located inside the blower, with both its head and tail ends placed within the blower. The hydrogen burner is inserted into the head end of the pulverized coal combustion cylinder. The hydrogen burner of this invention acts as a stable torch with high rigidity and high temperature, with a flame temperature as high as 1400-1500℃. When the pulverized coal in the combustion cylinder comes into contact with the hydrogen flame, the pulverized coal particles are rapidly heated and volatilized, causing the pulverized coal particles to break and pulverize, thereby being rapidly ignited inside the combustion cylinder. After preliminary combustion, the pulverized coal gas flow enters the gasification chamber along with the gas flow provided by the blower. Under high temperature and oxygen-deficient conditions, the pulverized coal generates combustible gases such as carbon monoxide and hydrogen, as well as activated semi-coke, which are then injected into the furnace to form a gas-like combustion torch, achieving the purpose of ignition and start-up of the pulverized coal boiler and stable combustion under low load. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a preferred embodiment of the hydrogen-coal powder gasification and combustion device of the present invention.

[0026] in, Figure 1 :

[0027] 1. Hydrogen burner; 2. Primary pulverized coal combustion chamber; 3. Primary air duct; 4. Secondary pulverized coal combustion chamber; 5. Elbow; 6. Pulverized coal concentration device; 7. Secondary air duct; 8. Secondary air cyclone separator; 9. Flame stabilizing ring; 10. Wall-mounted air chamber; 11. Wall-mounted air duct; 12. Gasification chamber. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0029] The following is a specific example. Figure 1 A preferred embodiment of the hydrogen-coal powder gasification and combustion device of the present invention will be described in detail.

[0030] like Figure 1 As shown, this hydrogen-coal pulverized gasification and combustion device includes a coal pulverized combustion cylinder, an air duct, a gasification chamber 12, and a hydrogen burner 1.

[0031] The following is a detailed description of the structure and connection method of the pulverized coal combustion cylinder, air duct, gasification chamber 12 and hydrogen burner 1.

[0032] The gasification chamber 12 has its cylinder wall made of heat-insulating material, and the internal environment is an oxygen-deficient environment. This enhances the gasification of pulverized coal in the oxygen-deficient environment of the gasification chamber 12, generating high-temperature active gases.

[0033] like Figure 1 As shown, the gasification chamber 12 is preferably a conical structure, with the small-radius end connected to and in communication with the air duct. The conical structure facilitates the diffusion of pulverized coal and hydrogen.

[0034] The vaporization chamber 12 is equipped with a wall that covers the entire inner wall of the vaporization chamber 12, forming a cylindrical conical structure. A channel is formed between the wall and the vaporization chamber 12, which is the wall-mounted air chamber 10. Several air ducts are provided on the wall, which connect the wall-mounted air chamber 10 and the hollow inner cavity of the vaporization chamber 12.

[0035] It should be noted that the wall-mounted air duct 11 in this embodiment is inclined on the wall, and the inclination direction is consistent with the taper direction of the vaporization chamber 12. This facilitates the diffusion of the airflow in the wall-mounted air duct 10 into the vaporization chamber 12, forming a concentrated airflow.

[0036] The presence of the wall-mounted air duct 11 can prevent the high-temperature pulverized coal airflow from adhering to the inner wall of the gasification chamber 12 and forming coke.

[0037] Hair dryer, such as Figure 1 As shown, it includes a primary air duct 3 and a secondary air duct 7. The diameter of the secondary air duct 7 is larger than that of the primary air duct 3. The secondary air duct 7 is connected to the wall and the inner cavity of the secondary air duct 7 is connected to the inner cavity of the wall. The secondary air duct 7 can supply air to the vaporization space inside the wall.

[0038] The primary air duct 3 is located inside the secondary air duct 7, that is, the secondary air duct 7 is fitted outside the primary air duct 3. The primary air duct 3 is also connected to the inner cavity of the wall, that is, it provides primary air supply to the vaporization space inside the wall.

[0039] like Figure 1 As shown, the end of the primary air duct 3 is provided with an elbow 5. The elbow 5 has a hollow structure and its inner cavity is connected to the primary air duct 3. At the same time, the pulverized coal thickening device 6 is located inside the elbow 5, that is, the pulverized coal enters the primary pulverized coal combustion chamber 2 through the elbow 5.

[0040] In a preferred embodiment, a secondary air cyclone separator 8 is provided between the inner wall of the secondary air duct 7 and the outer wall of the primary air duct 3, so that the secondary air can be easily transported to the gasification chamber 12 through the secondary air cyclone separator 8.

[0041] In addition, a flame stabilizing ring 9 is provided at one end of the primary air duct 3 facing the gasification chamber 12. When the hydrogen burner 1 is shut down, a high-temperature backflow flame is formed at the position of the flame stabilizing ring 9, which realizes the efficient combustion of the pulverized coal airflow and achieves partial pulverized coal gasification combustion.

[0042] The pulverized coal combustion tube includes at least one stage of pulverized coal combustion tube 2, with each stage of pulverized coal combustion tube connected end to end. A hydrogen burner 1 is inserted into the pulverized coal combustion tube at the end, and the diameter of the pulverized coal combustion tube gradually increases from the pulverized coal combustion tube near the hydrogen burner 1 to the pulverized coal combustion tube away from the hydrogen burner 1.

[0043] The diameter of the pulverized coal combustion cylinder gradually increases, which facilitates the gradual release of pulverized coal and provides a certain pressure for the diffusion of pulverized coal.

[0044] Specifically, the pulverized coal combustion chamber of this embodiment includes a primary pulverized coal combustion chamber 2 and a secondary pulverized coal combustion chamber 4 connected end to end, such as... Figure 1 As shown, the secondary pulverized coal combustion cylinder 4 and the primary pulverized coal combustion cylinder 2 are connected, and the diameter of the primary pulverized coal combustion cylinder 2 is smaller than that of the secondary pulverized coal combustion cylinder 4. Both the primary pulverized coal combustion cylinder 2 and the secondary pulverized coal combustion cylinder 4 are placed in the inner cavity of the primary air duct 3. The hydrogen burner 1 is inserted into the primary pulverized coal combustion cylinder 2. A pulverized coal concentration device 6 is installed at the end of the primary pulverized coal combustion cylinder 2. The pulverized coal concentration device 6 is used to supply pulverized coal to the pulverized coal combustion cylinder. The pulverized coal concentration device 6 is located inside the elbow 5.

[0045] A preferred embodiment of the present invention also provides a method for hydrogen-coal powder gasification and combustion, comprising the following steps:

[0046] (1) The hydrogen burner 1 provides a high-temperature hydrogen flame, which gradually ignites the pulverized coal in the primary pulverized coal combustion tube 2 and the secondary pulverized coal combustion tube 4 to form a high-temperature pulverized coal flame.

[0047] (2) After the high-temperature pulverized coal flame is mixed with the primary air and the secondary air, it enters the gasification chamber 12. The pulverized coal particles in the high-temperature pulverized coal flame generate high-temperature active gases under the action of hydrogen in the oxygen-deficient reducing atmosphere.

[0048] (3) High-temperature reactive gases are injected into the furnace as fuel for combustion.

[0049] The high-temperature reactive gases here are CO, H2, and reactive semi-coke substances.

[0050] To achieve efficient gasification of pulverized coal gas flow, it is preferable to mix some pure oxygen into the primary air duct 3 to enhance the initial combustion of pulverized coal gas flow in the primary pulverized coal combustion tube 2 and the secondary pulverized coal combustion tube 4.

[0051] The structure and length of the gasification chamber 12 vary depending on the coal quality. For high-quality bituminous coal, the gasification chamber 12 is shorter and there is no need to arrange a straight section. For low-quality bituminous coal, the flow velocity in the gasification chamber 12 is reduced and the length of the gasification chamber 12 is increased.

[0052] The principle of the hydrogen-coal pulverized gasification and combustion device and method is as follows:

[0053] The hydrogen-coal pulverized gasification combustion technology utilizes a specially designed hydrogen burner 1 to form a stable flare with high rigidity and high temperature, reaching a flame temperature of 1400-1500℃. When the oxygen-rich coal pulverized gas flows through the flare, the coal particles are rapidly heated, releasing volatilization and causing the coal particles to break and pulverize. This allows them to be rapidly ignited in the primary coal pulverized combustion chamber 2 and the secondary coal pulverized combustion chamber 4. After preliminary combustion, the coal pulverized gas flow enters the gasification chamber 12 along with a portion of the secondary air flow. The gasification chamber 12 is designed to be insulated. In the gasification chamber 12, the coal pulverized gas flow comes into contact with a portion of the secondary air flow. Under the high temperature and oxygen-deficient environment, the coal pulverized gas generates combustible gases such as carbon monoxide and hydrogen, as well as activated semi-coke, which is then injected into the furnace to form a gas-like combustion flare, achieving the purpose of ignition and start-up of the coal pulverized boiler and stable combustion under low load.

[0054] The hydrogen-coal pulverized gasification combustion technology of this invention combines traditional plasma ignition technology, micro-oil ignition technology, internal combustion technology, rich-lean combustion technology, and gasification technology. Its core idea is to utilize a high-temperature hydrogen flame core, employing oxygen-enriched combustion technology and a reasonable rich-lean separation technology, with staged combustion of the airflow. The pulverized coal airflow gradually burns within the primary pulverized coal combustion chamber 2 and the secondary pulverized coal combustion chamber 4, progressively amplifying the combustion energy. Subsequently, under a reducing atmosphere, coal gasification is achieved, and the high-temperature gas enters the furnace, mixing with oxygen within the furnace for gasification combustion, thus enabling boiler start-up and shutdown, and stable combustion at low loads.

[0055] Compared to plasma ignition technology and micro-oil ignition technology, hydrogen-coal powder gasification combustion technology has the advantages of high ignition energy, wide coal quality adaptability, high burnout rate after coal powder gasification combustion, no oil pollution, and no impact on SCR and electrostatic precipitators.

[0056] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0057] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0058] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hydrogen-coal pulverized gasification and combustion device, characterized in that, It includes a pulverized coal combustion cylinder, an air duct, and a gasification chamber. The gasification chamber is located at one end of the air duct and is connected to the air duct. The pulverized coal combustion cylinder is located in the inner cavity of the air duct, with both its head and tail ends placed in the inner cavity of the air duct. A hydrogen burner is inserted into the head end of the pulverized coal combustion cylinder. The ventilation duct includes a primary ventilation duct and a secondary ventilation duct. The secondary ventilation duct is fitted outside the primary ventilation duct. Both the primary ventilation duct and the secondary ventilation duct are connected to the gasification chamber. The pulverized coal combustion cylinder is placed inside the cavity of the primary ventilation duct.

2. The hydrogen-coal pulverized gasification and combustion device according to claim 1, characterized in that, The pulverized coal combustion chamber includes at least one stage of pulverized coal combustion chamber, with each stage of the pulverized coal combustion chamber connected end to end, and the hydrogen burner inserted into the end of the pulverized coal combustion chamber.

3. The hydrogen-coal pulverized gasification and combustion device according to claim 2, characterized in that, The diameter of the pulverized coal combustion cylinder gradually increases from the point closer to the hydrogen burner to the point farther away from the hydrogen burner.

4. The hydrogen-coal pulverized gasification and combustion device according to claim 2, characterized in that, The pulverized coal combustion tube includes a primary pulverized coal combustion tube and a secondary pulverized coal combustion tube connected end to end. The secondary pulverized coal combustion tube and the primary pulverized coal combustion tube are connected. The hydrogen burner is inserted into the primary pulverized coal combustion tube. A pulverized coal concentration device for supplying pulverized coal to the pulverized coal combustion cylinder is installed at the end of the primary pulverized coal combustion cylinder.

5. The hydrogen-coal pulverized gasification and combustion device according to claim 1, characterized in that, The end of the primary air duct is provided with an elbow.

6. The hydrogen-coal pulverized gasification and combustion device according to claim 1, characterized in that, A secondary air cyclone separator is provided between the inner wall of the secondary air duct and the outer wall of the primary air duct.

7. The hydrogen-coal pulverized gasification and combustion device according to claim 1, characterized in that, The end of the primary air duct facing the gasification chamber is provided with a flame stabilizing ring.

8. The hydrogen-coal pulverized gasification and combustion device according to any one of claims 1-7, characterized in that, The vaporization chamber is provided with a wall, and a wall-mounted air chamber is formed between the wall and the inner wall of the vaporization chamber. The wall is provided with a number of air ducts, which connect the wall-mounted air chamber and the hollow inner cavity of the vaporization chamber.

9. A combustion method using the hydrogen-coal pulverized gasification combustion device according to any one of claims 1-8, characterized in that, Includes the following steps: The hydrogen burner provides a high-temperature hydrogen flame to ignite the pulverized coal, forming a high-temperature pulverized coal flame. After the high-temperature pulverized coal flame mixes with the air, it enters the gasification chamber. The pulverized coal particles in the high-temperature pulverized coal flame generate high-temperature reactive gases under the action of hydrogen in the oxygen-deficient reducing atmosphere. High-temperature reactive gases are injected into the furnace as fuel for combustion.

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