CN210921340U

CN210921340U - Boiler capable of burning biomass fuel based on transformation of existing grate firing boiler

Info

Publication number: CN210921340U
Application number: CN201921793613.XU
Authority: CN
Inventors: 杨潇
Original assignee: Guangxi Xiaoneng Green Technology Co ltd
Current assignee: Guangxi Xiaoneng Green Technology Co ltd
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2020-07-03
Anticipated expiration: 2029-10-24

Abstract

The utility model discloses a combustible biomass fuel's boiler based on present layer fires boiler transformation, including boiler furnace and combustor, be equipped with the exhaust port on the furnace, furnace bottom is outwards equipped with flame retardant coating and heat preservation by the lining in proper order, and wherein the flame retardant coating is by furnace antetheca to furnace back wall slope, and flame retardant coating low side tip is equipped with the slagging scorification mouth that passes the heat preservation, the combustor includes venturi combustion nozzle, and venturi combustion nozzle establishes inside and outside furnace antetheca and intercommunication furnace wall, and the exit that venturi combustion nozzle is located furnace is equipped with the ignition nozzle, and the ignition nozzle passes through the pipeline intercommunication with the ignition gas source that sets up outside furnace, is equipped with the electrode of striking sparks on the ignition nozzle. The boiler is transformed by utilizing the existing grate firing boiler, the cost is saved, and the heating surfaces of the original boiler body and the boiler tail are not changed, so that the safety of the transformed boiler is not influenced, the space of a hearth can be fully utilized, the radiation heat exchange area is increased, and coking is not easy to occur.

Description

Boiler capable of burning biomass fuel based on transformation of existing grate firing boiler

Technical Field

The utility model relates to a layer fires the transformation technique of boiler specifically is a boiler of combustible biomass fuel based on current layer fires boiler transformation.

Background

With the increasing national environmental protection requirements and the increasing exhaustion of fossil energy, the efficient utilization of biomass fuel is more and more paid attention by people. However, there are a large number of coal-fired layer-combustion industrial boilers and heating boilers in China, as shown in fig. 4 and 5.

The biomass fuel is used as a renewable green fuel, has wide material sources and low price, and successively invents a biomass fuel forming particle combustion technology and a biomass fuel dust cloud combustion technology besides original and low-efficiency direct combustion.

The biomass fuel forming granule combustion technology is a method of drying and roughly grinding biomass fuel in a special independent factory, then pressing and forming the biomass fuel into granules, and then carrying out stratified combustion, which not only increases the fuel cost, but also does not overcome the low efficiency of the stratified combustion.

The biomass fuel dust cloud combustion technology is characterized in that biomass fuel bulk is crushed, dried and then ground into superfine powder, the fineness of the superfine powder needs to reach micron level, and then the superfine powder is combusted in a special heat-insulating combustion chamber to reach a high temperature of more than 1400 ℃, so that the chemical incomplete combustion loss q3 and the mechanical incomplete combustion loss q4 are reduced to zero, the fuel use efficiency is greatly improved, but the technology still has five defects:

firstly, a large amount of electric energy is consumed for preparing micron-sized ultrafine powder in an independent factory, and a large amount of heat energy is consumed for drying coarse and wet fuels, so that the fuel cost is increased;

secondly, the biomass fuel micron-sized superfine powder can generate high-concentration nitric oxide when being burnt at ultrahigh temperature in an insulated combustion chamber, and a large amount of denitration substances are consumed to reach the national specified nitric oxide emission standard, so that the running economy is reduced, and the serious high-temperature corrosion is generated on steel components of a boiler;

thirdly, the flame of the combustion mode only exists in the heat-insulating combustion chamber, and only high-temperature hot air which does not basically emit visible light is sprayed into the hearth of the boiler, so that the radiation heat exchange capability is reduced, and the flame can only be used on a special boiler but not on the existing boiler;

fourthly, the interface for feeding the biomass fuel powder into the combustor is arranged on an air outlet pipe of the air blower, and air and materials are mixed unevenly and are easy to break fire;

fifthly, when the existing biomass fuel is used in a boiler, only the problem of combustion is concerned, but the utilization of waste heat of exhaust gas is generally ignored, so that the exhaust gas temperature of the boiler is still higher, and a certain distance is reserved from the requirement of reaching the emission level of the boiler.

How to reform the existing coal-fired layer combustion industrial boiler and heating boiler into a boiler capable of combusting biomass fuel is a problem which is urgently needed to be solved at present.

SUMMERY OF THE UTILITY MODEL

The utility model provides a solve exist among the prior art not enough, provide a can burn biomass fuel's boiler based on present layer fires boiler transformation. The boiler is modified by utilizing the existing grate firing boiler, the cost is saved, the heating surfaces of the original boiler body and the tail part of the boiler are not changed, so that the safety of the modified boiler is not influenced, the Venturi combustion nozzle is arranged at the front coal hopper and the grate of the original boiler, the space of a hearth can be fully utilized, the radiation heat exchange area is increased, and the coking is not easy to occur.

Realize the utility model discloses the technical scheme of purpose is:

a boiler capable of burning biomass fuel based on the transformation of the existing layer combustion boiler comprises a boiler furnace and a burner, wherein a smoke exhaust port is arranged on the furnace, a fire-resistant layer and a heat-insulating layer are sequentially arranged at the bottom of the furnace from inside to outside, the fire-resistant layer inclines from the front wall of the furnace to the rear wall of the furnace, a slag removal port penetrating through the heat-insulating layer is arranged at the end part of the lower end of the fire-resistant layer, the burner comprises a Venturi combustion nozzle, the Venturi combustion nozzle is arranged on the front wall of the furnace and communicated with the inside and the outside of the wall of the furnace, an ignition nozzle is arranged at an outlet of the Venturi combustion nozzle in the furnace and communicated with an ignition gas source arranged outside the furnace,

the venturi combustion nozzle comprises a contraction section, a direct-current section, a diffusion section and a flow limiting section which are sequentially connected, wherein the contraction section and the diffusion section are hollow conical tubes, and the direct-current section and the flow limiting section are hollow cylindrical tubes.

The length of the straight flow section of the Venturi combustion nozzle is larger than or equal to the inner diameter of the straight flow section, in the combustion process, the flow speed of the air-material mixture in the straight flow section is larger than the flame propagation speed of the air-material mixture, and the flow speed of the air-material mixture at the outlet of the diffusion section is matched with the speed required by stable combustion of the air-material mixture.

The length of the straight section of the Venturi combustion nozzle is 2 times of the inner diameter of the Venturi combustion nozzle, so that backfire is prevented.

The length of the diffusion section of the Venturi combustion nozzle is 3-15 times of the inner diameter of the outlet of the Venturi combustion nozzle, so that the air-material mixture can be diffused more uniformly, and the air-material mixture can be combusted more fully.

The venturi combustion nozzle is made of heat-resistant steel.

The ignition gas source is canned natural gas.

The biomass fuel boiler is characterized in that biomass fuel powder with the fineness below 2mm is used in the boiler, the biomass fuel powder and air are conveyed to a pipeline by an air blower to form a wind-material mixture, the wind-material mixture is input from an inlet of a contraction section of a Venturi combustion nozzle, is ignited at an outlet of a flow limiting section of the Venturi combustion nozzle and is sprayed into a hearth for combustion, the biomass fuel wind-material mixture is ignited to be ignited by inputting gas, an ignition electrode ignites inflammable gas in the ignition nozzle, and the gas input can be cut off after the combustible gas ignition wind-material mixture is stably combusted.

The boiler that this technical scheme reformed transform, on the basis of current coal fired grate firing boiler, demolish coal equipment and stokehold coal scuttle, replace original grate mechanism for venturi combustion nozzle, and use insulating brick and resistant firebrick to build the ash hole bottom the furnace and build sealedly, remain original slagging scorification mouth, to the reciprocating grate boiler that has the arch of zhong, demolish the refractory material that covers on the arch of zhong, remain the water pipe system of original arch of zhong, become the radiation heating surface, the ignition nozzle after the transformation and the electrode of striking sparks all can insert original safety control system and carry out automatic control.

The boiler saves cost, has high safety, can fully utilize the space of a hearth by arranging the Venturi combustion nozzle at the position of the original grate mechanism, increases the radiation heat exchange area, and is not easy to coke.

Drawings

FIG. 1 is a schematic structural diagram of a boiler based on the transformation of a traveling grate boiler in the embodiment;

FIG. 2 is a schematic structural diagram of a boiler based on the transformation of a reciprocating grate boiler in the embodiment;

FIG. 3 is a schematic structural diagram of a Venturi combustion nozzle in the embodiment;

FIG. 4 is a schematic structural diagram of a conventional traveling grate boiler;

fig. 5 is a schematic structural diagram of a conventional reciprocating grate boiler.

In the figure, 1, a hearth 2, an exhaust port 3, a fire-resistant layer 4, an insulating layer 5, a slag removal port 6, a Venturi combustion nozzle 61, a contraction section 62, a direct-current section 63, a diffusion section 64, a flow limiting section 7, an ignition nozzle 8, an ignition gas source 9 and a water pipe system with a middle arch are arranged.

Detailed Description

The contents of the present invention will be further described with reference to the accompanying drawings and examples, but the present invention is not limited thereto.

Example 1:

the present example is further illustrated by taking the transformation of a traveling grate boiler as an example.

Referring to fig. 1, a boiler capable of burning biomass fuel based on the transformation of the existing layer combustion boiler comprises a boiler hearth 1 and a burner, wherein a smoke outlet 2 is arranged on the hearth 1, a fire-resistant layer 3 and a heat-insulating layer 4 are sequentially arranged at the bottom of the hearth 1 from inside to outside, the fire-resistant layer 3 inclines from the front wall of the hearth 1 to the rear wall of the hearth 1, a slag removing port 5 penetrating through the heat-insulating layer 4 is arranged at the end part of the lower end of the fire-resistant layer 3, the burner comprises a venturi combustion nozzle 6, the venturi combustion nozzle 6 is arranged at the front wall of the hearth 1 and communicated with the inside and the outside of the wall of the hearth 1, an ignition nozzle 7 is arranged at an outlet of the venturi combustion nozzle 6 in the hearth 1, the ignition nozzle 7 is communicated with an ignition air,

as shown in fig. 3, the venturi combustion nozzle 6 includes a contraction section 61, a flow-through section 62, a diffusion section 63 and a flow restriction section 64 which are connected in sequence, the contraction section 61 and the diffusion section 63 are hollow conical tubes, and the flow-through section 62 and the flow restriction section 64 are hollow cylindrical tubes.

The length of the straight section 62 of the venturi combustion nozzle 6 is greater than or equal to the inner diameter of the straight section 62, and during the combustion process, the flow velocity of the air-material mixture in the straight-flow section 62 is greater than the flame propagation velocity of combustion of the air-material mixture, if the flame propagation velocity of the millimeter-scale biomass fuel is in the range of 15-25m/s, the flow velocity of the air-material mixture in the straight-flow section 62 in this embodiment is 30m/s, so as to ensure that the combustion flame at the outlet of the Venturi combustion nozzle 6 cannot pass through the straight-flow section 62 and be tempered to the inlet, thereby achieving the effects of preventing tempering and improving safety, the flow speed of the air-material mixture at the outlet of the diffusion section 63 is matched with the speed required by the stable combustion of the air-material mixture, therefore, the flow speed of the air-material mixture at the outlet of the diffusion section 63 in this embodiment is 15m/s, so as to ensure that the air-material mixture is diffused by the diffusion section 63 and sprayed out from the flow-limiting section 64 and then is not scattered onto the inner container of the boiler to be combusted, thereby causing coking.

The straight flow section 62 of the venturi combustion nozzle 6 has a length 2 times its inner diameter to prevent backfiring.

The length of the diffusion section 63 of the venturi combustion nozzle 6 is 10 times of the inner diameter of the outlet of the venturi combustion nozzle, so that the diffusion of the air-fuel mixture is more uniform, and the combustion of the air-fuel mixture is more sufficient.

The venturi combustion nozzle 6 is made of 310S stainless steel to ensure continuous use in a high temperature environment.

The ignition gas source 8 is canned natural gas.

The boiler uses biomass fuel powder with the fineness below 2mm, the biomass fuel powder and air are conveyed to a pipeline by an air blower to form a wind-material mixture, the wind-material mixture is input from the inlet of the contraction section 61 of the Venturi combustion nozzle 6, is ignited at the outlet of the flow limiting section 64 of the Venturi combustion nozzle 6 and is sprayed into the hearth 1 for combustion, the biomass fuel wind-material mixture is ignited to be ignited by inputting gas, the ignition electrode ignites the combustible gas in the ignition nozzle 7, the gas input can be cut off after the combustion of the gas ignition wind-material mixture is stabilized, then the biomass fuel wind-material mixture in the hearth 1 is fully combusted, as the biomass fuel wind-material mixture is fully combusted in the hearth 1, the thermal efficiency of the boiler is improved to 90% from the original 65%, the direct economic benefit is improved by more than 25%, the discharge of harmful substances is reduced by 60% compared with the biomass fuel generated during the combustion of the existing layer combustion boiler, the concentration of smoke discharging dust is reduced from the original 80mg/m through thin film tube fruit cultivation to 30 mg/m through thin film fruit cultivation.

The modified boiler of the embodiment is based on the existing coal-fired grate boiler, the coal feeding equipment and the stokehole coal hopper are removed, the original grate mechanism is replaced by the Venturi combustion nozzle 6, the ash falling port at the bottom of the hearth 1 is sealed by using insulating bricks and refractory bricks, the original deslagging port 5 is reserved, and the modified ignition nozzle 7 and the modified ignition electrode can be connected into the original safety control system for automatic control.

Example 2:

the present example is further illustrated by taking the transformation of a reciprocating grate boiler as an example.

As shown in figure 2, for the reciprocating grate boiler with the middle arch, the refractory material covered on the middle arch is removed, the water pipe system 9 of the original middle arch is reserved and is changed into a radiation heating surface, and the other parts are modified into the same chain grate boiler.

Claims

1. A boiler capable of burning biomass fuel based on the transformation of the existing layer combustion boiler comprises a boiler furnace and a burner, wherein a smoke exhaust port is arranged on the furnace, a fire-resistant layer and a heat-insulating layer are sequentially arranged at the bottom of the furnace from inside to outside, the fire-resistant layer is inclined from the front wall of the furnace to the rear wall of the furnace, and a deslagging port penetrating through the heat-insulating layer is arranged at the end part of the lower end of the fire-resistant layer.

2. The boiler capable of combusting the biomass fuel, which is modified based on the existing grate firing boiler, according to claim 1, wherein the length of the straight section of the venturi combustion nozzle is greater than or equal to the inner diameter of the straight section, the flow velocity of the air-fuel mixture in the straight section is greater than the flame propagation velocity of the combustion of the air-fuel mixture during the combustion process, and the flow velocity of the air-fuel mixture at the outlet of the diffuser section is matched with the velocity required by the stable combustion of the air-fuel mixture.

3. The reformed biomass-fueled boiler based on the conventional grate-firing boiler, according to claim 1, wherein the straight-flow section of the venturi combustion nozzle has a length 2 times the inner diameter thereof.

4. The reformed biomass-fueled boiler based on the conventional grate-firing boiler, according to claim 1, wherein the venturi combustion nozzle has a diffuser section of a length 3 to 15 times the inner diameter of the outlet thereof.

5. The reformed biomass-fueled boiler based on the conventional grate firing boiler, according to claim 1, wherein the venturi-fired nozzle is made of heat resistant steel.

6. The retrofitted combustible biomass fuel boiler based on an existing grate firing boiler of claim 1, wherein said ignition gas source is canned natural gas.