CN116772195A - A biomass mixed-fired pulverized coal boiler and its use method - Google Patents

Abstract

The invention discloses a biomass mixed combustion pulverized coal boiler and a use method thereof, in particular to a boiler system for combusting biomass fuel together with pulverized coal in a mixed state, which comprises a pulverized coal burner, a biomass crushing system, a dry clinker treatment unit and the like. The biomass is fully ground and the pulverized coal in the hearth is mixed and combusted, so that the combustion efficiency of the boiler is remarkably improved.

Description

A biomass mixed-fired pulverized coal boiler and its use method

Technical field

The present invention relates to a biomass mixed-fired pulverized coal boiler and its use method, and to a boiler suitable for burning biomass fuel (mainly including wood fuel) together with pulverized coal in a mixed state. Specifically, the present invention relates to A biomass mixed combustion pulverized coal boiler.

Background technique

In recent years, in order to significantly reduce the consumption of fossil fuels, humans need and attempt to burn biomass fuels together with fossil fuels (such as coal, etc.) in a fully mixed state. To this end, researchers have developed a method of burning biomass fuel (for example, woody biomass fuel) and coal in a mixed state by using a pulverized coal boiler. That is, a small amount of biomass fuel is supplied to the coal bunker at a time, and is ground into powder material together with coal in the coal bunker, and then the powder material thus obtained is supplied to the furnace through air and burned in the furnace.

However, in the method of grinding biomass fuel together with coal using a coal mill, and then burning the powdery material thus obtained in a mixed state, as the proportion of biomass fuel in the powdery material increases, the efficiency of grinding coal tends to decrease. will decrease. So under current conditions, the proportion of biomass fuel burned with pulverized coal in the mixed state is limited to about 2-3% (by weight).

In order to increase the limited proportion of biomass fuel burned with pulverized coal in the mixed state, some researchers have proposed another method, in which the biomass fuel is ground by a dedicated biomass grinder and then processed by using a different method than that provided for pulverized coal. A separate burner of the burner supplies the biomass fuel completed by this grinding method to the furnace, and is finally burned in the furnace in a mixed state with pulverized coal. Indeed, this method can safely avoid the above-mentioned reduction in coal grinding efficiency. The proportion of biomass fuel in the ground or powdered material burned in the mixed state can be significantly increased without unduly reducing the coal grinding efficiency. However, this increased biomass fuel cannot be fully suspended and burned in the furnace, and the combustion efficiency of the fuel will in turn be reduced.

Contents of the invention

The present invention is proposed based on the above-mentioned problems in the related art. Therefore, an object of the present invention is to significantly increase the ratio of biomass fuel burned with pulverized coal in the mixed state, while allowing the use of biomass fuel with relatively large particle size (in particular, biomass fuel with a grinding particle size equal to or greater than 5 mm). material fuel), there is no need to add excessive equipment to the basic structure of conventional biomass mixed combustion pulverized coal boilers.

In order to achieve the above challenges, the present invention proposes a biomass mixed-fired pulverized coal boiler and its use method. A boiler configured to burn biomass fuel and pulverized coal in a mixed state; a pulverized coal burner for supplying pulverized coal to the furnace; a biomass burner for supplying biomass fuel to the furnace; and a biomass pulverizer, configured to pulverize biomass fuel to be supplied to the biomass burner; a dry clinker processing unit provided below the furnace, the dry clinker processing unit including a clinker conveyor configured to be at the bottom of the furnace conveying ash discharged from the furnace; and an air supply unit configured to supply combustion-supporting air to the ash discharged from the clinker conveyor to burn unburned biomass fuel contained in the ash discharged from the furnace bottom on the clinker conveyor components.

Preferably, the biomass grinder is configured to grind the biomass fuel into particles having a grinding particle size equal to or greater than 5 mm.

Preferably, the air supply unit is configured to supply combustion-supporting air to the ashes discharged from the furnace bottom so that the unburned components of the biomass fuel can be completely burned on the clinker conveyor.

Preferably, the boiler further includes an air input controller configured to optimize the combustion efficiency in the entire boiler by controlling a flow rate of air supplied to the interior of the furnace and a flow rate of air supplied from the air supply unit to the ash discharged from the furnace. .

Preferably, the boiler further includes a cooling air supply device configured to supply cooling air to the dry clinker processing device.

Description of drawings

Figure 1 is a partial structural diagram of a biomass mixed combustion pulverized coal boiler.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Please refer to Figure 1, an embodiment provided by the present invention. In the biomass mixed combustion pulverized coal boiler according to this embodiment, the biomass fuel with a grinding particle size of 5mm is supplied at a speed of 2.6t/h and the biomass fuel is supplied at a speed of 10.8t/h. The pulverized coal supplied at a rate of h is burned together in a mixed state, (in this case, the combustion rate of the biomass fuel, that is, the ratio of the biomass fuel burned together with the pulverized coal in the mixed state, is assumed to be 10%). Therefore, steam can be produced at 105t/h. Referring to Figure 1, this biomass mixed combustion pulverized coal boiler will be described.

In this embodiment, wood (or wood-based) biomass fuel dried to a moisture content of 20% is burned together with mixed pulverized coal in the boiler at a speed of 2.6t/h.

In the biomass mixed combustion pulverized coal boiler of this embodiment, as shown in Figure 1, the pulverized coal burners 4 are respectively arranged at the lower part of the furnace 1, and the biomass burners 5 are respectively arranged at the lower part of the furnace 1 relative to the pulverized coal burner 4. upper part. In addition, the dry clinker processing unit 21 is provided below the furnace body 1 and passes through the transition hopper 20 . The dry clinker processing unit 21 includes a conveyor belt 23 made of highly heat-resistant metal and arranged in a housing 22 of the unit 21 . The conveyor belt 23 is used to catch or receive the ash falling towards the bottom of the furnace, and is designed to move from left to right in the drawing at a speed of approximately 5 mm/second. Furthermore, the conveyor belt 23 is driven by drive wheels or rollers 24 .

Referring to Figure 1, each cooling air inlet hole 31 is generally open outwardly while being configured to be optionally closed by a flap. In this configuration, when the pressure in the furnace is a negative value, the valve is opened to suck outside air from each cooling air inlet hole 31, and when the pressure in the furnace is a positive value, the valve is closed to prevent gas generated in the furnace flows out from each hole 31. In addition, in the biomass mixed combustion pulverized coal boiler of this embodiment, an air supply unit 32 composed of a gas source, a pipe, etc. is provided near the transition hopper 20 . The flow rate of air supplied from the air supply unit 32 is controlled by the air input controller 60 .

In this case, the coal supplied from the coal bunker 11 is ground once by the coal grinder 6 and then sent to the furnace 1 and burned by each pulverized coal burner 4 in the lower combustion area F1. At the same time, the biomass fuel is once supplied to the biomass fuel bin 12 and is ground into a grinding particle size of 5mm by the biomass grinder 13, and then the ground biomass fuel particles are sent to the furnace 1, and are crushed by each upper biomass The burner 5 burns in the upper combustion zone F2. At this time, the particles of biomass fuel are blown upward by the combustion gas generated in the downward combustion area F1 and suspended in the furnace 1 . However, the medium particles and coarse particles in the suspended particles will flow around or downward along the inner wall of the furnace 1, and then fall on the conveyor belt 23 of the dry clinker processing device 21 through the transition hopper 20.

Claims (10)

1. A biomass mixed-fired pulverized coal boiler and its use method, characterized in that it includes: a boiler configured to burn biomass fuel together with pulverized coal in a mixed state; including a pulverized coal burner for burning Pulverized coal is supplied to the furnace; a biomass burner is included for supplying biomass fuel to the inner furnace; and a biomass pulverizer is configured to pulverize the biomass fuel to be supplied to the biomass burner. 2. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that: there is a dry clinker processing unit below the boiler, and the dry clinker processing unit includes a clinker conveyor, The clinker conveyor is configured to convey ash discharged from the boiler at the bottom of the furnace; an air supply unit is configured to supply combustion air to the ash on the clinker conveyor to burn the ash discharged from the furnace bottom on the clinker conveyor. Contains the unburned components of biomass fuel. 3. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that: the biomass mill is configured to grind biomass fuel into a particle size equal to or greater than 5 mm. Particles. 4. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that: the air supply unit is configured to supply combustion-supporting air to the ashes discharged from the bottom of the furnace to facilitate the combustion of biomass fuel. The unburned components can be completely burned on the clinker conveyor. 5. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that: it should also include an air input controller configured to control the flow rate of the combustion air supplied to the interior of the furnace. and the flow rate of the combustion air supplied from the combustion air supply unit to the ash discharged from the bottom of the furnace to optimize combustion efficiency throughout the boiler. 6. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that: the biomass burner is located above the pulverized coal burner; the biomass crusher is used to crush biomass fuel. 7. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that: it should also include a cooling air supply device configured to supply cooling gas to the dry clinker processing unit. 8. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that: it should also include a coal grinder configured to grind coal to produce and supply coal. Pulverized coal for pulverized burner. 9. A biomass mixed-fired pulverized coal boiler and its use method according to claim 1, characterized in that it includes the following steps: using a biomass grinder to grind biomass fuel; and using a biomass burner to supply the boiler Grinding biomass fuel; supplying pulverized coal to the boiler through the use of pulverized coal burners; burning biomass fuel contained in the ash discharged from the bottom of the furnace on the conveyor belt of the dry clinker handling unit by supplying air to the ash on the clinker conveyor The device is located under the furnace body. 10. A biomass mixed-fired pulverized coal boiler and its use method according to claim 9, characterized in that: the biomass fuel is ground into particles with a grinding particle size equal to or greater than 5 mm by using a biomass grinder; Optimize the combustion efficiency of the entire boiler by controlling the flow rate of air supplied to the interior of the boiler and to the ash discharged from the bottom of the clinker conveyor furnace.