Ignition stable combustion and deep peak regulation device for coal-fired boiler by fixed bed gasification synthesis gas

Abstract

The utility model relates to an ignition, stable combustion and deep peak regulation technology of a coal-fired boiler, in particular to an ignition, stable combustion and deep peak regulation device for the coal-fired boiler through carbon-based fuel gasification synthesis gas. The device comprises a gasification furnace body, high-temperature synthesis gas dust removal equipment, an emergency emptying stop valve, a branch pipeline stop valve, a boiler synthesis gas burner and a power plant coal-fired boiler, the gasification furnace body is connected with the high-temperature synthesis gas dust removal equipment, the emergency emptying stop valve is arranged at the upper end of the high-temperature synthesis gas dust removal equipment, and the high-temperature synthesis gas dust removal equipment is connected with a boiler synthesis gas burner on a coal-fired boiler of a power plant through the branch pipeline stop valve. Synthesis gas generated by gasification of carbon-based fuel enters the boiler to be combusted for ignition, stable combustion and deep peak regulation of the coal-fired boiler, and the coal-fired boiler has the advantages of being high in reliability and good in operation economical efficiency.

Description

TECHNICAL FIELD

[0001] The utility model relates to coal -fired boiler ignition, steady combustion and depth peak shaving technology, concretely is a kind of carbon-based fuel gasification synthesis gas gives coal -fired boiler ignition steady combustion and depth peak shaving device. BACKGROUND

[0002] Coal combustion process is very complex chemical reaction, relative to gas and liquid combustion, coal combustion has the problem of difficult ignition, low burnout rate. Generally, when the boiler ignites, it needs to be ignited by an ignition oil gun, burn a large amount of fuel oil, or use a plasma torch to heat the boiler furnace to ignite the surrounding coal powder fuel. A large amount of fuel oil needs to be burned to ensure the success rate of ignition when the boiler starts.

[0003] In a coal-fired boiler, the excess air coefficient of coal combustion is generally large. From the principle, it is easy to cause unstable combustion and thus cause boiler accidents. In particular, the four corners / wall type tangential furnace using straight-flow burners, under the condition of low boiler load, the tangential diameter in the furnace changes, and the swirling intensity decreases, which is prone to unstable combustion. Therefore, during the operation of the boiler, the ignition oil gun or the plasma torch is usually continuously operated, and the purpose is to maintain the stability of the boiler operation by a reliable ignition source.

[0004] In recent years, with the increasing proportion of fluctuating power such as wind power and solar power, coal-fired power plants have gradually taken on the heavy responsibility of grid load peak shaving. Deep peak shaving requires coal-fired boilers to have a wide load adjustment range. The main factor restricting peak shaving is the stability of low-load combustion of the boiler. The minimum load of the boiler using a straight-flow burner for peak shaving can only be reduced to about 30%, and the oil gun fuel quantity needs to be increased during low-load operation to ensure stable combustion.

[0005] The current operation cost of using an oil gun or plasma for boiler ignition, stable combustion and peak shaving is very high. Using synthesis gas generated by fixed bed gasification to replace oil gun or plasma ignition can effectively reduce the operation cost. First, the fixed bed has low investment cost and reliable operation, and can provide a stable ignition source. Second, the raw material of fixed bed gasification can come from block coal, biomass or garbage in the power plant coal yard, and the materials are taken locally. Finally, the synthesis gas generated by fixed bed pure oxygen gasification has high calorific value, and the gas combustibility is higher than that of liquid and solid, so the ignition and stable combustion performance is good.

[0006] In order to ensure the ignition, stable operation and deep peak shaving of coal-fired boilers, and effectively reduce the boiler ignition and operation cost, a new boiler ignition and stable combustion system needs to be designed. Utility model content

[0007] The utility model aims at providing a kind of carbon-based fuel gasification synthesis gas gives coal-fired boiler ignition stable combustion and depth peak shaving device, it uses carbon-based fuel to enter the boiler combustion by gasification and produce synthesis gas, and it is ignited, stable combustion and depth peak shaving for coal-fired boiler, with the characteristics of high reliability, operation economy.

[0008] The technical scheme of the present application is as follows:

[0009] A kind of carbon-based fuel gasification synthesis gas gives coal-fired boiler ignition stable combustion and depth peak shaving device.

[0010] The device contains gasification furnace body, high-temperature synthesis gas dust removal equipment, emergency venting cut-off valve, branch pipeline cut-off valve, boiler synthesis gas burner and power plant coal-fired boiler;

[0011] The gasification furnace body is connected with high-temperature synthesis gas dust removal equipment, the emergency venting cut-off valve is arranged at the upper end of the high-temperature synthesis gas dust removal equipment, and the high-temperature synthesis gas dust removal equipment is connected with the boiler synthesis gas burner on the power plant coal-fired boiler through the branch pipeline cut-off valve.

[0012] The raw material of the gasification furnace can be lump coal, pulverized coal, briquetted biomass, RDF, biomass powder, waste tire powder or lump, carbon-based fuel containing carbon solid waste, etc.; the type of power plant coal-fired boiler can be four-corner / wall type tangential furnace, front and rear wall counter-boiler and W-flame boiler.

[0013] The carbon-based fuel gasification system gasification furnace type includes but is not limited to fixed bed gasification furnace, fluidized bed gasification furnace, gas flow bed gasification furnace, etc., and the gasification system includes carbon-based fuel feeding system, gasification furnace body, slag removal system, ash water system, etc. Taking pure oxygen continuous gasification system as an example, the overall structure type of the gasification furnace is vertical furnace body, which includes gasification raw material feeding bin, cut-off valve, material channeling groove, locking bin, gasification furnace body, gas inlet cavity and slag discharge bin from top to bottom in sequence; the gasification furnace body is provided with top feeding port, synthesis gas outlet, water cooling jacket and grate.

[0014] The water inlet of the carbon-based fuel gasification furnace water cooling jacket comes from the low-temperature heater of the power plant, and the water outlet of the gasification furnace jacket is sent into the deaerator of the power plant.

[0015] The number of gasification furnace bodies provided in the carbon-based fuel gasification system is 1-10.

[0016] The high-temperature synthesis gas dust removal equipment is a cyclone separator made of refractory casting or a high-temperature filter with sintered metal lining.

[0017] The emergency venting cut-off valve is an electric valve or pneumatic valve that can be remotely controlled by the control system, and the venting outlet is installed with a flare with automatic control ignition device.

[0018] The synthesis gas conveying pipelines all adopt casting pipelines with refractory lining and internal insulation.

[0019] The branch pipeline cut-off valve is installed on the branch pipeline before the synthetic gas is transported into the boiler, and is divided into corresponding branch pipelines according to the number of the synthetic gas burners, and the cut-off valve is installed on each branch pipeline, and the cut-off valve is an electric valve or a pneumatic valve which can be remotely controlled by a control system, and the installation of the cut-off valve on the branch pipeline can effectively reduce the equipment cost.

[0020] The boiler synthetic gas burner is used for burning carbon-based fuel gasification synthetic gas. The synthetic gas is transported into the boiler and is burned at the outlet of the synthetic gas burner, and the high-temperature flue gas of the burning is used for igniting the pulverized coal into the furnace, and is used for starting ignition of the boiler, stable combustion during operation of the boiler and deep load regulation of the boiler. Further, the installation position of the boiler synthetic gas burner in the boiler can be as follows:

[0021] In the four-corner / wall type tangential furnace, the synthetic gas burners are installed at the lowermost end and the middle of the pulverized coal straight-flow burners. Two boiler synthetic gas burners are installed on each of the four corners of the straight-flow burners.

[0022] In the front and back wall opposite-arrangement boiler, the synthetic gas burners are arranged in a staggered manner with the pulverized coal burners, and are installed below the pulverized coal burners at the lowermost end of the front and back walls and between the pulverized coal burners at the lowermost end and the upper row of the pulverized coal burners, and are arranged in two rows on the front wall and two rows on the back wall in an opposite-arrangement type.

[0023] The working principle of the utility model is as follows:

[0024] The block coal, briquetted biomass, RDF and other block organic raw materials in the coal storage yard of the power plant are gasified in the gasification furnace, the generated synthetic gas is transported into the boiler through the high-temperature pipeline with refractory and internal insulation, is dedusted in the high-temperature cyclone separator, most of the dust is filtered out, is transported into the boiler, is burned through the boiler synthetic gas burner, provides ignition heat for the pulverized coal burning when the boiler starts, the synthetic gas continuously and stably burns when the boiler operates, provides a high-temperature environment, surrounds the pulverized coal, and maintains stable combustion of the pulverized coal in the furnace of the boiler. When the power plant deeply regulates the peak, the load of the boiler is reduced, the processing capacity of the gasification furnace is increased or a standby furnace is opened, the amount of synthetic gas is increased, the synthetic gas is burned in the boiler, and the stable operation of the boiler under low load is maintained.

[0025] The utility model has the advantages of stable operation, high reliability and good economic benefits.

[0026] (1) The utility model replaces the oil gun ignition system or the plasma ignition system of the coal-fired boiler, has the advantages of stable operation, high reliability and good economic benefits.

[0027] (2) The water in the jacket of the gasification furnace comes from the circulating water system of the power plant, is sent into the deaerator of the power plant after being heated, and the synthetic gas conveying pipeline adopts the internal insulation form, and the overall gasification system has small heat loss to the boiler.

[0028] (3) The gasification furnace quantity can be flexibly arranged according to actual requirements of the power plant, so as to meet ignition, stable combustion operation or deep peak regulation operation. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a schematic diagram of the carbon-based fuel gasification synthesis gas for the coal-fired boiler ignition, stable combustion and deep peak regulation system of the utility model.

[0030] Figure 2 It is a schematic diagram of the arrangement position of the synthesis gas burner in the four-corner / wall type tangential furnace.

[0031] Figure 3 It is Figure 2 a side view.

[0032] Figure 4 It is a schematic diagram of the arrangement position of the synthesis gas burner in the front and back wall opposed boiler.

[0033] Among them, the sign is: 1, gasification furnace body, 2, high-temperature synthesis gas dust removal equipment, 3, emergency venting cut-off valve, 4, branch pipeline cut-off valve, 5, coal-fired boiler of power plant, 6, gasification raw material feeding bin, 7, material chute, 8, locking bin, 9, deslagging bin, 10, air inlet cavity, 11, boiler synthesis gas burner, 12, main combustion zone of boiler furnace, 13, four-corner / wall type tangential furnace straight-flow pulverized coal burner, 14, front and back wall of front and back wall opposed boiler water-cooled wall center line, 15, front and back wall of front and back wall opposed boiler side wall water-cooled wall center line, 16, front and back wall of front and back wall opposed boiler cyclone pulverized coal burner. DETAILED DESCRIPTION

[0034] The utility model will be described in further detail below in combination with the drawings and specific embodiments. Example One

[0035] The utility model in relation to the problem that the oil gun ignition operation cost of the coal-fired boiler of the current thermal power plant is high, the reliability of the plasma ignition system is low and the operation cost is high and it is difficult to guarantee deep peak regulation, proposes a kind of fixed bed gasification synthesis gas for coal-fired boiler ignition, stable combustion and deep peak regulation system, effectively reduces the boiler ignition, stable combustion operation cost, and participates in the deep peak regulation of thermal power plant, and the minimum load of boiler operation can be reduced to 20%.

[0036] As shown in Figure 1 , the embodiment provides a kind of carbon-based fuel gasification synthesis gas for coal-fired boiler ignition, stable combustion and deep peak regulation device.The overall device includes carbon-based fuel gasification furnace system, synthesis gas gas pipeline, synthesis gas boiler combustion system.

[0037] The gasification furnace type of the carbon-based fuel gasification system is a continuous pure oxygen fixed bed gasification furnace, a fluidized bed gasification furnace, a dry powder gasification furnace, a coal water slurry gasification furnace, etc. The continuous pure oxygen fixed bed gasification furnace is taken as an example to illustrate the system composition of the gasification furnace. The overall structure type of the gasification furnace is a vertical furnace body, which sequentially includes a gasification raw material bin 6, a shut-off valve, a material chute 7, a lock bin 8, a gasification furnace body 1, an air inlet cavity 10 and a slag discharge bin 9 from top to bottom. The gasification furnace body is provided with a top feed inlet, a synthesis gas outlet, a water cooling jacket and a furnace grate.

[0038] The blocky organic raw materials such as lump coal, briquetted biomass, garbage RDF from the coal storage yard of the power plant are selected by selecting 5-50 mm raw materials, added to the gasification raw material bin 6, and sent to the lock bin 8 through the material chute 7 by opening the shut-off valve. The gasification raw materials are added to the gasification furnace body by operating the lower end switch valve of the lock bin 8. The gasification agent is introduced into the gasification furnace body at a steam oxygen ratio (kg / Nm3) of 2.2-3.5 from the air inlet cavity 10 at the lower part of the gasification furnace to produce synthesis gas.

[0039] Taking the ignition of a 660 MW supercritical boiler as an example, one or two fixed bed pure oxygen continuous gasification furnaces are configured. When two furnaces are configured, one is a standby furnace. The maximum gasification coal consumption of the gasification furnace is 200 t / d. Before the start of the boiler, the gasification furnace is started first, the gasification agent flow is adjusted, the synthesis gas production of the gasification furnace is stabilized at 11000 Nm3 / h, and the synthesis gas is transported to the boiler for ignition. When the steam turbine is connected to the grid, the gasification agent flow of the gasification furnace is adjusted first, the synthesis gas flow is increased to 15000 Nm3 / h, and then the grid connection is started. After the grid connection is completed, the load of the gasification furnace is reduced, and the synthesis gas flow is stabilized at 10000 Nm3 / h to maintain stable combustion of the boiler. The gasification operation pressure in the gasification furnace is 1-70 kPa.G, so no synthesis gas induced draft fan needs to be installed on the gas pipeline.

[0040] The outer wall of the gasification furnace is designed with a water cooling jacket, which recovers energy and ensures the utilization rate of the ignition fuel. Taking the ignition of a 660 MW supercritical boiler as an example, the water inlet of the water cooling jacket comes from the low temperature heater of the power plant, the water quantity is about 3 t / h, the inlet water temperature is 70℃, and the water is heated to 154℃ by the gasification jacket and sent to the deaerator of the power plant.

[0041] The temperature of the synthesis gas at the outlet of the gasification furnace periodically fluctuates according to the material frequency and is maintained in the range of 300-550℃. The synthesis gas pipeline adopts cast pipeline with refractory lining and internal insulation. An emergency venting shut-off valve 3 is arranged on the pipeline, which is an electric valve or a pneumatic valve that can be remotely controlled by the control system. The venting outlet is provided with a flare with an automatic control ignition device.

[0042] The high-temperature synthesis gas removes solid particles brought from the gasifier through the high-temperature synthesis gas dust removal equipment 2, and the type of the high-temperature synthesis gas dust removal equipment 2 is a refractory cast-made cyclone separator or a sintered metal-lined high-temperature filter.

[0043] The quick cut-off valve is installed before the synthesis gas enters the boiler. Because the amount of the synthesis gas is large, the inner diameter of the conveying pipeline reaches 1-1.1 meters, and the cost of installing the cut-off valve capable of resisting high temperature and having a large diameter is high, therefore, the method of installing the cut-off valve in the branch pipeline is adopted. The branch pipeline cut-off valve 4 is installed on the branch pipeline before the synthesis gas enters the boiler, and is divided into corresponding branch pipelines according to the number of the synthesis gas burners, and the cut-off valve is installed on each branch pipeline. The cut-off valve is an electric valve or a pneumatic valve which can be connected to the control system for remote control. The installation of the cut-off valve in the branch pipeline can effectively reduce the equipment cost.

[0044] The synthesis gas enters the main combustion zone 12 of the boiler hearth to burn, and the synthesis gas should be burned on the boiler synthesis gas burner 11 designed according to the composition of the synthesis gas. The type of the boiler 5 can be a four-corner / wall tangentially cut circular boiler, a front-back wall opposed boiler and a "W" flame boiler.

[0045] Figure 2 、 3 The synthesis gas burners are arranged on the four-corner / wall tangentially cut circular boiler. Generally, the middle position of the straight-flow pulverized coal burner of the boiler is the installation position of the ignition oil gun. When the gasification synthesis gas is used for ignition and stable combustion, the boiler synthesis gas burner 11 is installed at the position of the original oil gun, that is, the middle position of the straight-flow pulverized coal burner 13 of the four-corner / wall tangentially cut circular boiler, and one boiler synthesis gas burner 11 is additionally arranged at the lowermost position of the straight-flow pulverized coal burner 13 of the four-corner / wall tangentially cut circular boiler. Two boiler synthesis gas burners are arranged on each straight-flow burner at the four corners. Example Two

[0046] On the basis of example 1, the arrangement of the synthesis gas burners on the front-back wall opposed boiler is carried out.

[0047] Figure 4 The arrangement of the synthesis gas burners on the front-back wall opposed boiler is shown. The synthesis gas is sent into the main combustion zone 12 of the boiler hearth, and the boiler synthesis gas burners 11 and the front-back wall opposed boiler cyclone pulverized coal burners 16 are arranged in a staggered manner in the front-back wall opposed boiler, are installed below the lowermost row of the pulverized coal burners of the front-back wall and are arranged in a row. In addition, one row of the boiler synthesis gas burners is arranged between the lowermost row of the pulverized coal burners and the upper row of the pulverized coal burners. Two rows of the boiler synthesis gas burners are arranged on the front wall, and similarly, two rows of the boiler synthesis gas burners are arranged on the rear wall. The front-back wall opposed boiler cyclone pulverized coal burners 16 are arranged in a front-back wall opposed type on the front-back wall.

[0048] The arrangement of the synthesis gas burners on the front-back wall opposed boiler is provided with the front-back wall water-cooled wall center line 14 of the front-back wall opposed boiler and the side wall water-cooled wall center line 15 of the front-back wall opposed boiler. Example three

[0049] On the basis of example 1 and example 2, the number of gasifiers is increased, and the amount of synthesis gas is increased, so that stable combustion of the boiler at a minimum of 20% load can be realized.

[0050] Taking 600MW supercritical boiler deep peak shaving as an example, six gasifiers are arranged in the fixed bed pure oxygen continuous gasification system, and one of them is standby. When the boiler is stably running, one gasifier is normally running at full load, maintaining stable combustion of the boiler, and the other four boilers are in hot standby state for a long time. When the boiler load is reduced, the hot standby gasifier is gradually started, the gasification agent flow is increased to increase the amount of synthesis gas, and the gasification agent flow is controllable. With the change of the boiler load, the gasification agent flow is adjusted in proportion. When the boiler load is reduced by 20%, the gasification synthesis gas flow is increased by 12000Nm3 / h. When the boiler is stably running at 20% load, 60000Nm3 / h of synthesis gas generated by the gasification system enters the boiler for combustion.

[0051] In all the schemes mentioned above, the connection between the two components can be selected according to the actual situation, such as welding, bolt and nut cooperation connection, bolt or screw connection or other known connection mode, which will not be described one by one, and the welding is preferred when the fixed connection is mentioned above, although the embodiments of the utility model have been shown and described, for those skilled in the art, it can be understood that the embodiments can be changed, modified, replaced and modified in various ways without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A fixed bed gasification synthesis gas ignites and stabilizes combustion and deep peak shaving device for coal-fired boiler, characterized in that: the device contains gasifier body (1), high temperature synthesis gas dust removal equipment (2), emergency venting cut-off valve (3), branch pipeline cut-off valve (4), boiler synthesis gas burner (11) and coal-fired boiler (5) of power plant; The gasifier body (1) is connected with the high temperature synthesis gas dust removal equipment (2), the emergency venting cut-off valve (3) is arranged at the upper end of the high temperature synthesis gas dust removal equipment (2), and the high temperature synthesis gas dust removal equipment (2) is connected with the boiler synthesis gas burner (11) on the coal-fired boiler (5) of the power plant through the branch pipeline cut-off valve (4).

2. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 1, characterized in that: The overall structure type of the gasifier is a vertical furnace body, a locking bin (8) is arranged on the gasifier body (1), the locking bin (8) and the gasification raw material feeding bin (6) are connected through a material sliding chute (7), and an air inlet cavity (10) and a slag discharge bin (9) are arranged below the gasifier body (1).

3. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 1, characterized in that: The type of the gasifier body (1) includes one of the following: a fixed bed gasifier, a fluidized bed gasifier or an entrained flow gasifier; The type of the coal-fired boiler (5) of the power plant includes one of the following: a four-corner / wall type tangential furnace, a front-back wall opposite boiler or a W flame boiler.

4. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 1, characterized in that: The number of the gasifier body (1) is 1-10.

5. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 1, characterized in that: The high temperature synthesis gas dust removal equipment (2) is a refractory cast cyclone separator or a sintered metal lined high temperature filter.

6. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 1, characterized in that: The emergency venting cut-off valve (3) is an electric valve or a pneumatic valve which can be remotely controlled by a control system, and the venting outlet is provided with a flare equipped with an automatic control ignition device.

7. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 1, characterized in that: The branch pipeline cut-off valve (4) is arranged on the branch pipeline before the synthesis gas is sent into the boiler, and is divided into corresponding branch pipelines according to the number of the synthesis gas burners, and the branch pipeline cut-off valve (4) is arranged on each branch pipeline, and the branch pipeline cut-off valve (4) is an electric valve or a pneumatic valve which can be remotely controlled by a control system.

8. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 3, characterized in that: The coal-fired boiler (5) of the power plant is a four-corner / wall type tangential furnace, a boiler synthesis gas burner (11) is arranged at the middle position of the four-corner / wall type tangential furnace straight-flow pulverized coal burner (13), and one boiler synthesis gas burner (11) is additionally arranged at the lowermost position of the four-corner / wall type tangential furnace straight-flow pulverized coal burner (13).

9. The fixed bed gasification syngas igniting and stabilizing combustion and deep peak shaving device for coal-fired boilers according to claim 3, characterized in that: The coal-fired boiler (5) of the power plant is a front-back wall opposite boiler, the synthesis gas is sent into the main combustion zone (12) of the boiler hearth, the boiler synthesis gas burners (11) and the front-back wall opposite boiler swirl pulverized coal burners (16) are arranged in a staggered manner, are arranged below the front-back wall opposite boiler swirl pulverized coal burners (16) at the lowermost end of the front-back wall, and are arranged in a row; and a row of boiler synthesis gas burners (11) are arranged between the front-back wall opposite boiler swirl pulverized coal burners (16) at the lowermost end and the front-back wall opposite boiler swirl pulverized coal burners (16) arranged above them.

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