CN101007956B - Throat structure of two-stage biomass gasifier - Google Patents

Abstract

The invention relates to a two-stage biomass gasification furnace throat structure, which includes a throat tapering section, a throat section, a throat expanding section, and an air injection system composed of an air nozzle, an air main pipe, and an air intake pipe. , the air main pipe is arranged along the circumference of the gasifier and communicates with the air inlet pipe, and an odd number of air nozzles are evenly distributed on the air main pipe to connect with the throat section. The biomass pyrolysis gas generated upstream of the throat enters the throat section through the narrowing section of the throat, and meets the high-temperature air ejected from the air nozzle for combustion, so that the entire area forms a stable combustion state with an odd number of torches burning. Most of the tar that flows through is cracked at high temperature, and finally enters the downstream furnace through the gradual expansion section of the throat to participate in the gasification reaction. The invention combines the pyrolysis characteristics of biomass and the combustion characteristics of gas fuel, so that the biomass pyrolysis products flowing through can burn stably, reach a high temperature state, and crack most of the tar, thereby greatly reducing the tar level of the gas produced by the gasifier.

Description

Throat structure of two-stage biomass gasifier

technical field

The invention relates to a throat structure of a two-stage biomass gasification furnace, which is applied to the two-stage biomass gasification furnace and relates to the fields of environmental protection, new energy and the like.

Background technique

Biomass energy as a renewable energy has been paid more and more attention. Biomass gasification for power generation is an effective way to utilize biomass. In the existing biomass gasification power generation technology, the gasifier mostly adopts the downdraft or fluidized bed furnace type. The down-suction fixed bed gasifier pushes the biomass directly onto the grate, the air enters from the middle of the material layer, and the gasification gas is drawn out from the bottom of the grate; the fluidized bed gasifier passes the air from bottom to top Fire grate, the material on the fire grate is in a fluid state by blowing, and the gasification gas is drawn from the top. Since the air is directly passed into the carbon layer, considering factors such as slagging, the temperature is generally controlled to be relatively low, up to about 800°C, and because it is a gas-solid phase reaction, it is easy to cause local high temperature. Because the high temperature cannot be generated in the gasification layer, the tar content of the generated gasification gas is relatively high, which not only increases the purification cost, easily causes secondary pollution, but also easily blocks the pipeline, increases the frequency of cleaning the cylinder of the internal combustion engine, and affects the power generation efficiency .

Contents of the invention

The purpose of the present invention is to address the deficiencies of the prior art, to provide a two-stage biomass gasifier throat structure, using a specially designed throat structure and rotating air nozzle, so that the biomass pyrolysis gas can be partially oxidized in the throat area And generate high temperature, so that the tar pyrolysis.

In order to achieve this purpose, the present invention combines the pyrolysis characteristics of biomass, determines the inner diameter of the throat according to the amount of pyrolysis gas, and arranges a number of air nozzles in the middle and upper part of the throat section. Mouth area to mix well.

The throat tapering section should ensure that the pyrolysis material coming down from the pyrolysis section passes through the throat section smoothly without blockage and stagnation.

In order to ensure that the pyrolysis gas can burn stably, an odd number of air nozzles are arranged on a cross section. The throat area burns stably with the mechanism of mutual ignition, thereby generating local high temperature and cracking most of the tar in the pyrolysis gas. The throat section must have a certain height to ensure the complete combustion of tar cracking time and oxygen.

The gradually expanding section of the throat should ensure that the flue gas in the throat area enters the furnace body smoothly.

The specific structure of the present invention is: the throat structure of the two-stage biomass gasifier is composed of a throat tapering section, a throat section, a throat expanding section and an air injection system; a throat tapering section, a throat section and a throat The diverging section is connected sequentially from top to bottom and is integrally poured with refractory concrete. The half-cone angle of the throat tapering section and the half-cone angle of the throat expanding section are both in the range of 25° to 35°. The height of the furnace is equivalent to the inner diameter of the furnace, and the inner diameter of the throat section is 0.5 to 0.6 times that of the inner diameter of the furnace. The air injection system is composed of air nozzles, air main pipes and air intake pipes. The air main pipes are arranged along the circumference of the gasifier and connected with the air intake pipes. An odd number of air nozzles are evenly distributed on the air main pipes. The air nozzle inlets The throttle ring structure is adopted in the tube, the nozzle of the air nozzle is connected to the throat section, the angle between the axis of the air nozzle and the cross section of the nozzle is within the range of 25° to 35°, and the axis of the air nozzle to the throat section The angle between the horizontal line and the axis of the nozzle is between 20° and 30°, and the distance between the nozzle of the air nozzle and the upper entrance of the throat section is 0.2 to 0.3 times the height of the throat section.

After the biomass is pyrolyzed, biomass pyrolysis gas and residual carbon are produced upstream of the throat, and enter the throat section through the tapered section of the throat. In the air nozzle at the throat section, the high-temperature air and the pyrolysis gas are combusted to form a local high temperature to crack the tar at high temperature. Finally, it flows through the gradual expansion section and enters the downstream furnace body to participate in the gasification reaction.

According to the characteristics of biomass, the two-stage gasifier produces gasification gas through biomass pyrolysis, partial oxidation, and gasification, and uses the high temperature generated by partial oxidation at the throat to crack most of the tar, thereby producing gas suitable for internal combustion engines. The burned biomass gasification gas achieves the clean and efficient use of biomass energy, a renewable energy source. Combining the pyrolysis characteristics of biomass and the combustion characteristics of gaseous fuels, the present invention adopts the above series of technical measures to make the biomass pyrolysis products flowing through the throat section burn stably and reach a high temperature state to crack most of the tar, thus greatly Reduce tar levels in gasifier gas.

Description of drawings

Fig. 1 is a longitudinal sectional view of the throat structure of the two-stage biomass gasifier of the present invention.

In Fig. 1, 1 is the narrowing section of the throat, 2 is the air nozzle, 3 is the air main pipe, 4 is the throat section, 5 is the gradual expansion section of the throat, 6 is the air intake pipe, and 7 is the throttle ring.

Fig. 2 is a top view of the throat section of the two-stage biomass gasifier of the present invention.

Detailed ways

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings.

The throat structure of the two-stage biomass gasifier of the present invention is shown in FIG. 1 , and is composed of a throat tapering section 1 , a throat section 4 , a throat expanding section 5 and an air injection system. The throat tapered section 1, the throat section 4 and the throat tapered section 5 are sequentially connected from top to bottom and formed by integral casting of refractory concrete.

The half-cone angle β of throat tapering section 1 and the half-cone angle γ of throat tapering section 5 are both in the range of 25° to 35°, and a tapered formwork is used during pouring. The height L of the throat section 4 is equivalent to the inner diameter D of the furnace, and the inner diameter d of the throat section 4 is 0.5-0.6 times of the inner diameter D of the furnace.

The air injection system is composed of an air nozzle 2, an air main pipe 3 and an air intake pipe 6. The air main pipe 3 is arranged along the circumference of the gasifier and communicated with the air intake pipe 6. An odd number of air injection pipes are evenly distributed on the air main pipe 3. Pipe 2, the inlet of the air nozzle 2 is installed with a throttle ring 7 in the pipe, and the nozzle of the air nozzle 2 communicates with the throat section 4. The welded air nozzle 2, the air main pipe 3 and the air intake pipe 6 are connected to the shell of the furnace body in advance before the throat section 4 is poured.

The angle θ between the axis of the air nozzle 2 and the cross section of the nozzle is in the range of 25° to 35°, and the distance between the nozzle of the air nozzle 2 and the upper entrance of the throat section 4 is 0.2 to 0.3 times the height L of the throat section.

A large amount of biomass pyrolysis gas is generated upstream of the throat, and when it flows through the throat tapering section 1 and enters the throat section 4, it encounters high-temperature air ejected from the air nozzle 2 for combustion. Each nozzle forms a flare, which rotates and burns in the throat section 4, and at the same time can ignite the combustion of the downstream nozzles, so that the entire area forms a stable burner. Local high temperature is generated in this area, and most of the tar flowing through is pyrolyzed at high temperature. Finally, it enters the downstream furnace through the gradual expansion section of the throat to participate in the gasification reaction.

Fig. 2 is a top view of the throat section of the two-stage biomass gasifier of the present invention. As shown in Figure 2, the air injection system is composed of air nozzle 2, air main pipe 3, and air intake pipe 6. The air main pipe 3 is arranged along the circumference of the gasifier and communicated with the air intake pipe 6. Evenly distribute an odd number of air nozzles 2, install a throttle ring 7 in the pipe at the inlet of the air nozzle 2, and the angle α between the horizontal line connecting the nozzle of the air nozzle 2 to the throat section axis and the axis of the nozzle is 20°～30° ° between.

The hot air that participates in combustion enters the air main pipe 3 from the air intake pipe 6, and then distributes into the air nozzle 2, and is sprayed into the furnace according to the axial direction of the air nozzle 2. In order to ensure that the air volume in each air nozzle is uniform, each A throttling ring 7 is installed in the pipe at the inlet of the air nozzle 2 .

Claims (1)

1. A two-stage biomass gasifier throat structure, characterized in that it consists of a throat tapering section (1), a throat section (4), a throat expanding section (5) and an air injection system; the throat The tapering section (1), the throat section (4) and the throat expanding section (5) are connected sequentially from top to bottom and are integrally poured with refractory concrete. The half-cone angle of the throat tapering section (1) and The half-cone angles of the throat expanding section (5) are all in the range of 25° to 35°, the height of the throat section (4) is equivalent to the inner diameter of the furnace, and the inner diameter of the throat section (4) is 0.5 of the inner diameter of the furnace. ~ 0.6 times; the air injection system is composed of an air nozzle (2), an air main pipe (3), and an air intake pipe (6), and the air main pipe (3) is arranged along the circumference of the gasifier and connected with the air intake pipe ( 6) Connected to each other, an odd number of air nozzles (2) are evenly distributed on the air main pipe (3), and a throttle ring (7) is installed in the inlet of the air nozzle (2), and the nozzle of the air nozzle (2) is connected In the throat section (4), the angle between the axis of the air nozzle (2) and the cross-section of the nozzle is in the range of 25° to 35°, and the horizontal line connecting the nozzle of the air nozzle (2) to the axis of the throat section is in line with the axis of the nozzle The included angle of the axes is between 20° and 30°, and the distance between the nozzle of the air nozzle (2) and the upper entrance of the throat section (4) is 0.2 to 0.3 times the height of the throat section.

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