Hydrogen pulverized coal gasification combustion device and method

Abstract

The invention provides a hydrogen pulverized coal gasification combustion device and method, and relates to the technical field of power generation. A hydrogen burner is used as a stable torch with high rigidity and high temperature, the flame temperature reaches up to 1400-1500 DEG C, pulverized coal in a pulverized coal combustion cylinder makes contact with hydrogen flame, pulverized coal particles are rapidly heated, released and volatilized, the pulverized coal particles are broken and smashed, and the pulverized coal is gasified and combusted. The pulverized coal airflow enters the gasification chamber together with the airflow provided by the air duct after being subjected to primary combustion, the pulverized coal generates combustible gases such as carbon monoxide and hydrogen and activated semicoke in a high-temperature oxygen-deficient environment, and then the combustible gases and the activated semicoke are sprayed into a hearth to form a gas-like combustion torch; the purposes of ignition starting and low-load stable combustion of the pulverized coal boiler are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of power generation, and in particular to a hydrogen pulverized coal gasification combustion device and method. Background Art

[0002] With the continuous adjustment and deepening of the national energy structure, the installed capacity of renewable energy in my country has increased year by year. So far, clean power sources with seasonal and intermittent characteristics such as hydropower and wind power have continued to develop rapidly. However, while renewable energy has continued to develop rapidly in recent years, some regions have experienced serious problems of wind and solar power abandonment. For coal-fired power generation units themselves, in order to better adapt to the requirements of deep peak regulation and improve the safety and reliability of unit operation, it is necessary to carry out necessary and more in-depth corresponding optimization and transformation of the units. The first thing to pay attention to is stable combustion under low load and low SCR inlet flue gas temperature.

[0003] In order to further tap the low-load stable combustion capability of the boiler and realize the goal of deep peak regulation of the unit to 15% of the rated load under conventional coal quality, the technologies currently adopted are: plasma stable combustion modification and micro-oil combustion technology modification, and auxiliary combustion device modification, hot primary air blending furnace smoke modification, hot primary air heater modification, dynamic separator modification and other schemes are carried out to improve the 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 low-load stable combustion of the boiler. Due to the limited energy of the ignition source of the plasma ignition body, plasma ignition technology has high requirements for coal quality. Coal quality fluctuations can easily cause unstable flames, and oil needs to be added to assist combustion. At the same time, plasma ignition technology will have arc breaking and short cathode and anode life during operation, which requires regular replacement. Poor coal quality also has problems such as low burnout rate, and the air preheater needs frequent soot blowing. Micro-oil combustion technology uses a micro-oil gun as an ignition source to achieve cold start-up and low-load stable combustion of the boiler. The fuel output of micro-oil ignition technology is adjustable, and the adaptability of coal types is wider than that of plasma ignition technology. However, there is a problem of incomplete oil combustion in the micro-oil ignition process, which poses a major safety hazard to equipment such as electrostatic precipitators.

[0005] In order to solve the above problems and achieve stable combustion under low-load conditions of the boiler while meeting the deep peak regulation requirements of the unit, it is necessary to develop a new type of combustion device. Summary of the invention

[0006] In view of this, one of the purposes of the present invention is to provide a hydrogen pulverized coal gasification combustion device to solve the technical problem in the prior art that the combustion device operates poorly under ultra-low load conditions.

[0007] The second object of the present invention is to provide a hydrogen coal powder gasification combustion method

[0008] In order to achieve one of the above-mentioned purposes, the present invention provides a hydrogen pulverized coal gasification combustion device, comprising a pulverized coal combustion cylinder, a wind cylinder and a gasification chamber, wherein the gasification chamber is arranged at one end of the wind cylinder and is connected to the wind cylinder, the pulverized coal combustion cylinder is arranged in the inner cavity of the wind cylinder, and its head end and tail end are both placed in the inner cavity of the wind cylinder, and the head end of the pulverized coal combustion cylinder is inserted with a hydrogen burner.

[0009] Preferably, the pulverized coal combustion tube comprises at least one stage of pulverized coal combustion tube, the pulverized coal combustion tubes at each stage are connected end to end, and the hydrogen burner is inserted into the pulverized coal combustion tube at the end.

[0010] Preferably, the diameter of the pulverized coal combustion tube increases gradually from the pulverized coal combustion tube close to the hydrogen burner to the pulverized coal combustion tube far from the hydrogen burner.

[0011] Preferably, the pulverized coal combustion tube comprises 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 providing pulverized coal to the pulverized coal combustion tube is installed at the end of the first-level pulverized coal combustion tube.

[0013] Preferably, the air duct includes a primary air duct and a secondary air duct, the secondary air duct is sleeved on the outside of the primary air duct, the primary air duct and the secondary air duct are both connected to the gasification chamber, and the first-level pulverized coal combustion tube and the second-level pulverized coal combustion tube are both placed in the inner cavity of the primary air duct.

[0014] Preferably, an elbow is provided at the end of the primary air cylinder.

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

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

[0017] Preferably, a wall is provided in the vaporization chamber, and a wall-adherent wind chamber is formed between the wall and the inner wall of the vaporization chamber. A plurality of wind ducts are provided on the wall, and the wind ducts connect the wall-adherent wind chamber and the hollow inner cavity of the vaporization chamber.

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

[0019] The hydrogen burner provides a high-temperature hydrogen flame to ignite the pulverized coal and form a high-temperature pulverized coal flame;

[0020] After the high-temperature pulverized coal flame is mixed with wind, it enters the gasification chamber. The pulverized coal particles in the high-temperature pulverized coal flame generate high-temperature active gas under the action of hydrogen in the oxygen-deficient reducing atmosphere.

[0021] High temperature active gas is injected into the furnace as fuel for combustion.

[0022] The hydrogen pulverized coal gasification combustion device and method provided by the present invention have the following technical effects:

[0023] The hydrogen pulverized coal gasification combustion device mainly consists of a pulverized coal combustion tube, a wind tube, a gasification chamber and a hydrogen burner. The gasification chamber is arranged at one end of the wind tube and is connected with the wind tube. The pulverized coal combustion tube is located in the inner cavity of the wind tube, and its head end and tail end are both placed in the inner cavity of the wind tube. The head end of the pulverized coal combustion tube is inserted into the hydrogen burner. The hydrogen burner of the invention serves as a stable torch with strong rigidity and high temperature, and the flame temperature is as high as 1400-1500°C. The pulverized coal in the pulverized coal combustion tube contacts with the hydrogen flame, and the pulverized coal particles are quickly heated and released to volatilize, so that the pulverized coal particles are broken and crushed, and thus are quickly ignited in the pulverized coal combustion tube. After preliminary combustion, the pulverized coal airflow enters the gasification chamber with the airflow provided by the wind tube. The pulverized coal generates combustible gases such as carbon monoxide and hydrogen and activated semi-coke in a high-temperature oxygen-deficient environment, and then is sprayed into the furnace to form a gas-like combustion torch, so as to achieve the purpose of ignition and start-up of the pulverized coal boiler and stable combustion at low load. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a structural schematic diagram of a preferred embodiment of the hydrogen pulverized coal gasification combustion device of the present invention.

[0026] in, Figure 1 :

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

[0028] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0029] The following is combined with specific Figure 1 A preferred embodiment of the hydrogen pulverized coal gasification combustion device of the present invention is described in detail.

[0030] like Figure 1 As shown, the hydrogen pulverized coal gasification combustion device includes a pulverized coal combustion tube, a wind tube, a gasification chamber 12 and a hydrogen burner 1.

[0031] The detailed structure and connection method of the pulverized coal combustion cylinder, the air cylinder, the gasification chamber 12 and the hydrogen burner 1 are described in detail below.

[0032] The wall of the gasification chamber 12 is made of heat-insulating material, and the inner cavity forms an oxygen-deficient environment, which strengthens the gasification of coal powder in the oxygen-deficient environment of the gasification chamber 12 to generate high-temperature active gas.

[0033] like Figure 1 As shown, the gasification chamber 12 is preferably in a conical structure, with the small radius end connected to and communicated with the wind tube, and the conical structure facilitates the enhancement of the diffusion of coal powder and hydrogen.

[0034] A wall is provided inside the vaporization chamber 12, and the wall covers the entire inner wall of the vaporization chamber 12, that is, it also presents a cylindrical conical structure. A channel is formed between the wall and the vaporization chamber 12, and the channel is the wall-attached wind chamber 10. A plurality of air ducts are provided on the wall, and the air ducts connect the wall-attached wind chamber 10 and the hollow inner cavity of the vaporization chamber 12.

[0035] It should be noted that the wall-attached air duct 11 of this embodiment is inclined on the wall, and the inclination direction is consistent with the taper direction of the vaporization chamber 12, so that the airflow in the wall-attached air chamber 10 is easily diffused into the vaporization chamber 12 to form a concentrated airflow.

[0036] The existence of the wall-attached air duct 11 can prevent the high-temperature coal powder airflow from adhering to the inner wall of the gasification chamber 12 to form coking.

[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 the diameter 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 provide secondary air supply for the gasification space in the wall.

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

[0039] like Figure 1 As shown, an elbow 5 is provided at the end of the primary air duct 3. The elbow 5 is a hollow structure. The inner cavity of the elbow 5 is connected to the primary air duct 3. At the same time, the coal powder concentration device 6 is located in the elbow 5, that is, the coal powder enters the primary coal powder combustion tube 2 through the elbow 5.

[0040] As a preferred embodiment, a secondary air cyclone 8 is provided between the inner wall of the secondary air cylinder 7 and the outer wall of the primary air cylinder 3 , and the secondary air cyclone 8 facilitates the secondary air to be transported to the gasification chamber 12 .

[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 stops operating, a high-temperature reflow flame is formed at the position of the flame stabilizing ring 9, thereby achieving efficient combustion of the pulverized coal airflow and partial gasification and combustion of the pulverized coal.

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

[0043] The diameter of the pulverized coal combustion tube is gradually increased, which, on the one hand, facilitates the gradual release of the pulverized coal, and on the other hand, provides a certain pressure for the diffusion of the pulverized coal.

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

[0045] A preferred embodiment of the present invention further provides a hydrogen pulverized coal gasification combustion method, comprising the following steps:

[0046] (1) The hydrogen burner 1 provides a high-temperature hydrogen flame to gradually ignite 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 gas under the action of hydrogen in the oxygen-deficient reducing atmosphere;

[0048] (3) High temperature active gas is sprayed into the furnace as fuel and burned.

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

[0050] In order to achieve efficient gasification of the pulverized coal airflow, it is preferred to mix some pure oxygen into the primary air duct 3 to strengthen the initial combustion of the pulverized coal airflow in the primary pulverized coal combustion tube 2 and the secondary pulverized coal combustion tube 4.

[0051] For different coal qualities, the structure and length of the gasification chamber 12 vary to a certain extent. For high-quality bituminous coal, the length of the gasification chamber 12 is shorter and no straight section is required; for low-quality bituminous coal, the flow rate in the gasification chamber 12 is reduced and the length of the gasification chamber 12 is increased.

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

[0053] The hydrogen pulverized coal gasification combustion technology utilizes a specially designed hydrogen burner 1 to form a stable torch with strong rigidity and high temperature. The flame temperature is as high as 1400-1500°C. When the oxygen-rich pulverized coal airflow passes through the torch, the pulverized coal particles are rapidly heated, releasing volatility, causing the pulverized coal particles to break and pulverize, thereby being rapidly ignited in the primary pulverized coal combustion tube 2 and the secondary pulverized coal combustion tube 4. After preliminary combustion, the pulverized coal airflow enters the gasification chamber 12 with part of the secondary airflow. The gasification chamber 12 is designed to be insulated. The pulverized coal airflow contacts part of the secondary airflow in the gasification chamber 12. The pulverized coal generates combustible gases such as carbon monoxide and hydrogen and activated semi-coke in a high-temperature, oxygen-deficient environment, which are then sprayed into the furnace to form a gas-like combustion torch, thereby achieving the purpose of ignition and start-up of the pulverized coal boiler and stable combustion at low load.

[0054] The hydrogen pulverized coal gasification combustion technology of the present invention is a combination of traditional plasma ignition technology, micro-oil ignition technology, internal combustion combustion technology, concentrated-light combustion technology and gasification technology. Its core idea is to utilize the high-temperature fire core of hydrogen, adopt oxygen-enriched combustion technology, reasonable concentrated-light separation technology, and air flow staged combustion. The pulverized coal airflow gradually burns in the primary pulverized coal combustion tube 2 and the secondary pulverized coal combustion tube 4, and the combustion energy is gradually amplified. Then, the coal is gasified in a reducing atmosphere, and the high-temperature fuel gas enters the furnace, mixes with the oxygen in the furnace, and gasifies and burns, so as to realize the start and stop of the boiler and stable combustion at low load.

[0055] Compared with plasma ignition technology and micro-oil ignition technology, hydrogen pulverized coal gasification combustion technology has the characteristics of large ignition energy, wide adaptability to coal quality, high burnout rate after pulverized coal gasification combustion, no oil pollution, and no effect on SCR and electrostatic precipitator.

[0056] In the description of the present invention, it should be noted that, unless otherwise specified, "multiple" means two or more than two; the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0057] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0058] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A hydrogen pulverized coal gasification combustion device, characterized in that: It includes a pulverized coal combustion tube, a wind tube and a gasification chamber. The gasification chamber is arranged at one end of the wind tube and is connected to the wind tube. The pulverized coal combustion tube is arranged in the inner cavity of the wind tube, and its head end and tail end are both placed in the inner cavity of the wind tube. The head end of the pulverized coal combustion tube is inserted with a hydrogen burner.

2. The hydrogen pulverized coal gasification combustion device according to claim 1, characterized in that: The pulverized coal combustion tube comprises at least one level of pulverized coal combustion tube, and the pulverized coal combustion tubes of each level are connected end to end, and the hydrogen burner is inserted into the pulverized coal combustion tube at the end.

3. The hydrogen pulverized coal gasification combustion device according to claim 2, characterized in that: The diameter of the pulverized coal combustion tube increases gradually from the pulverized coal combustion tube close to the hydrogen burner to the pulverized coal combustion tube far from the hydrogen burner.

4. The hydrogen pulverized coal gasification combustion device according to claim 2, characterized in that: The pulverized coal combustion tube comprises a primary pulverized coal combustion tube and a secondary pulverized coal combustion tube connected end to end, the secondary pulverized coal combustion tube is connected to the primary pulverized coal combustion tube, and the hydrogen burner is inserted into the primary pulverized coal combustion tube; A pulverized coal concentration device for providing pulverized coal to the pulverized coal combustion tube is installed at the end of the first-level pulverized coal combustion tube.

5. The hydrogen pulverized coal gasification combustion device according to claim 4, characterized in that: The wind tube includes a primary wind tube and a secondary wind tube, the secondary wind tube is sleeved on the outside of the primary wind tube, the primary wind tube and the secondary wind tube are both connected to the gasification chamber, and the first-level coal powder combustion tube and the second-level coal powder combustion tube are both placed in the inner cavity of the primary wind tube.

6. The hydrogen pulverized coal gasification combustion device according to claim 5, characterized in that: An elbow is provided at the end of the primary air cylinder.

7. The hydrogen pulverized coal gasification combustion device according to claim 5, characterized in that: A secondary air cyclone is provided between the inner wall of the secondary air cylinder and the outer wall of the primary air cylinder.

8. The hydrogen pulverized coal gasification combustion device according to claim 5, characterized in that: A flame stabilizing ring is provided at one end of the primary air duct facing the gasification chamber.

9. The hydrogen pulverized coal gasification combustion device according to any one of claims 1 to 8, characterized in that: A wall is arranged in the gasification chamber, a wall-adherent wind chamber is formed between the wall and the inner wall of the gasification chamber, a plurality of wind ducts are arranged on the wall, and the wind ducts communicate the wall-adherent wind chamber and the hollow inner cavity of the gasification chamber.

10. A combustion method using the hydrogen pulverized coal gasification combustion device according to any one of claims 1 to 9, characterized in that: The following steps are involved: The hydrogen burner provides a high-temperature hydrogen flame to ignite the pulverized coal and form a high-temperature pulverized coal flame; After the high-temperature pulverized coal flame is mixed with wind, it enters the gasification chamber. The pulverized coal particles in the high-temperature pulverized coal flame generate high-temperature active gas under the action of hydrogen in the oxygen-deficient reducing atmosphere. High temperature active gas is injected into the furnace as fuel for combustion.

Images