CN100513869C - Biomass high temperature combustion boiler - Google Patents

Abstract

The invention is high-efficiency and low-pollution biomass high-temperature combustion boiler and belongs to the boiler technical field. The invention comprises a biomass granule feeding device, a fuel even distribution plate, a cross flue tube, a radiate diversion block, an air nozzle in sections, a cyclone dust collector, a liquid drainage pool, a furnace, and a heat convection chamber. The invention is characterized in that a hopper of the biomass granule feeding device is arranged above the boiler for pre-drying; radiate diversion blocks are arranged in good order in the boiler; the pre-heated high-temperature is injected upwards into a hearth from the nozzle sections in a tangential direction to realize the staged and swirl combustion; the bottom is equipped with a gas, liquid and solid phase high-temperature cyclone segregator; the central high-temperature flue gas flows through a central flue tube to the upper cross flue tube and then enters the annular clearance between the furnace and the boiler wall and the hot convection chamber from below the boiler wall. The invention combines characteristics of biomass fuel and comprehensively absorbs the advantages of high-temperature air combustion, staged combustion, cyclone combustion, cyclone dust collection, liquid drainage, flue gas recirculation and other technologies, so the invention can realize the clean and high-efficiency use of the renewable energy of biomass.

Description

Biomass high temperature combustion boiler

Technical field:

The invention belongs to the technical field of boilers, and in particular relates to a biomass briquette fuel boiler.

Background technique:

Biomass energy has always been an important energy source for human survival, and occupies an important position in the entire energy system. It ranks fourth in the world's total energy consumption after coal, oil and natural gas. Biomass fuel mainly includes the following aspects: ① crop straw and agricultural processing residues; ② forest and forestry processing residues; ③ human and animal manure, industrial organic waste and aquatic plants; ④ urban domestic sewage and garbage. At present, there are three technologies for the utilization of biomass energy: biomass gasification, liquefaction, and direct combustion, all of which have certain problems. Gasification and liquefaction technology burn biomass after multiple conversions and purifications. The intermediate links not only increase the investment and operation costs, but also reduce the total utilization efficiency of biomass energy. Moreover, gasification and liquefied fuels have low calorific value, and they need to be improved in terms of stable operation, tar removal, and gas purification; while direct combustion technology is more efficient and has no secondary pollution problems caused by tar, so relatively speaking, The advantages of direct combustion are obvious. "China Energy" (2004, 26(9): page 39-42) pointed out that due to the low combustion temperature of the current direct combustion method, the ash accumulation and slagging caused by low melting point fly ash, as well as the combustion process will produce A series of problems such as particle emissions that have an impact on human health limit this extensive application. In addition, due to the high water content of biomass, much of the heat generated by combustion is wasted on the evaporation of water, which makes the utilization rate of biomass combustion heat in current fixed-bed and fluidized-bed boilers low. According to the combustion characteristics of biomass, the biomass high-temperature combustion boiler of the present invention comprehensively absorbs the advantages of high-temperature air combustion, staged combustion, cyclone combustion, cyclone dust removal, liquid slag removal technology and flue gas recirculation, and solves the current biomass direct combustion Existing technical problems, to achieve high thermal efficiency, low pollution, safe, large-scale low-cost thermal utilization of biomass.

Invention content:

The present invention applies high-temperature combustion technology to the direct combustion of biomass, and adopts technologies such as liquid slag discharge technology, staged combustion technology and flue gas recirculation, in order to improve the combustion efficiency of biomass, make the temperature field in the furnace uniform, and increase the volumetric heat. Load, improve boiler thermal efficiency, solve fly ash deposition and slagging problems, reduce pollutant emissions, and achieve efficient and stable combustion of biomass and clean emissions.

A high-efficiency and low-pollution biomass high-temperature combustion boiler of the present invention has common features including a furnace wall and an internal furnace, and is characterized in that an inverted cone-shaped hopper of a biomass particle feeder is arranged above the boiler, and a feed opening is sealed on the hopper , the lower part of the hopper is connected with the combustion chamber surrounded by the furnace, and the rotating shaft equipped with spiral blades is arranged along the axis of the hopper. The fuel uniform distribution plate, the inner wall of the furnace is inlaid with patchwork radiation guide blocks, the middle and lower part of the furnace body is equipped with segmented air nozzles, and the bottom of the furnace leads to the gas-liquid-solid three-phase high-temperature cyclone separator through multiple tangential through holes , the high-temperature cyclone separator connects with the central smoke pipe upwards, and opens downward to the liquid slag discharge pool. The central smoke pipe extends upward along the furnace axis and communicates with the horizontal cross smoke pipe on the upper part of the furnace. In the flue between the furnace and the furnace wall, the lower part of the flue is provided with a flue gas outlet that is connected to the steam generation chamber, and the flue gas outlet of the steam generation chamber is connected to the air preheater, and finally leads to the chimney.

The hopper of the biomass particle feeder in the present invention is arranged above the boiler and can convectively exchange heat with the flue gas. The moisture of the biomass particles is heated and evaporated, and the water vapor is discharged from the discharge port to realize the preliminary drying of the biomass particles. The throat of the hopper and the biomass particles accumulated in the hopper block the flue gas, so that a large amount of flue gas cannot be discharged from the top, and the recirculation of the flue gas is realized. A small amount of flue gas discharged from the gap between the biomass particles can play a role The positive effect of preheating and drying the biomass pellets, so this non-complete sealing method has a double advantage.

The biomass particles are driven by the motor through the shaft coupling to rotate the shaft equipped with the helical structure, and through the fuel uniform distribution plate installed at the bottom of the rotating shaft, the feed distribution of the biomass particles in the furnace is evenly realized. Moreover, due to the unique structural design and rotating motion of the fuel uniform distribution plate, the biomass will not be deposited on the smoke pipe, resulting in failure of feeding and flameout.

The furnace wall is inlaid with well-arranged radiation guide blocks, which are used to increase the residence time of biomass above the furnace and increase the convective heat transfer between biomass particles and high-temperature flue gas. At the same time, the setting of radiation guide blocks and the central smoke pipe It can increase the radiation heat transfer in the furnace, and can preheat the biomass to a higher temperature before combustion, which is beneficial to realize high-temperature combustion; The high-temperature air after preheating will meet to realize high-temperature, graded and swirling combustion.

The liquid residue and dust-laden flue gas after combustion enter the gas-liquid-solid three-phase high-temperature cyclone separator arranged at the bottom of the furnace tangentially downward, and the liquid residue and smoke enter the liquid slag discharge downward, and the effectively purified high-temperature flue gas flows from the center flue The pipe flows through the cross smoke pipe, and the high-temperature flue gas passes through the smoke pipe to exchange heat with the biomass particles outside the smoke pipe in the form of convection-radiation heat transfer. It is discharged from the upper part of the furnace and enters the compartment and furnace After convective heat exchange in the gallbladder, it enters the steam generating chamber from the outlet at the lower part of the furnace, exchanges heat with water, and generates steam.

Description of drawings:

Fig. 1 is a cross-sectional view of a biomass high-temperature combustion boiler of the present invention.

1 is the motor, 2 is the coupling, 3 is the feeding port, 4 is the hopper, 5 is the rotating shaft, 6 is the spiral blade, 7 is the furnace, 8 is the fuel uniform distribution plate, 9 is the cross pipe, 10 is Radiation diversion block, 11 is segmented air nozzle, 12 is central smoke pipe, 13 is cyclone separator, 14 is slag discharge outlet, 15 is liquid slag discharge tank, 16 is tangential inlet, 17 is furnace wall, 18 is The secondary outlet of the flue gas, 19 is a clapboard, the third outlet of the flue gas is 20, the water inlet is 21, the smoke pipe is 22, the baffle chamber is 23, the steam outlet is 24, and the water vapor outlet of the hopper is 25.

FIG. 2 is a top view of the fuel distribution plate 8 .

FIG. 3 is a top view of the installation position of the cross pipe 9 and the radiation deflector block 10 .

Detailed ways:

The specific implementation of the biomass high-temperature combustion boiler of the present invention will be further described below in conjunction with the accompanying drawings.

The structure of the biomass high-temperature combustion boiler of the present invention is shown in Figure 1, which mainly includes a motor 1, a coupling 2, a feed port 3, a hopper 4, a rotating shaft 5, a spiral blade 6, and a fuel uniform distribution plate 8. Biomass particle feeding device, furnace 7, radiation guide block 10, preheating chamber and combustion chamber composed of sectional air nozzle 11, cyclone separator 13, central smoke pipe 12, cross smoke pipe 9, liquid slag discharge tank The flue gas ash discharge device that consists of 15, the partition plate 19, the smoke pipe 22, and the steam generation chamber that the baffle chamber 23 forms.

The hopper 4 of the biomass particle feeding device is made of materials with excellent thermal conductivity and heat resistance, and is installed above the furnace 7 to exchange heat with the high-temperature flue gas discharged from the cross pipe 9 to pre-heat the biomass particles. Drying; the spiral blade 6 in the hopper 4 not only has the function of screw feeding, but also plays the role of stirring the biomass particles, so that the biomass particles can be fully preheated and dried; Completely sealed, the high-temperature flue gas and radiant heat penetrating from the gaps of the biomass particles also have a drying effect on the biomass particles, and the water vapor generated by drying is discharged from the water vapor outlet 25 of the hopper. The cone angle of the hopper 4 is obliquely upward 30-45° with the horizontal line, and the lower end has a throat of 25-35 mm.

The structure of the fuel distribution plate 8 is as shown in Figure 2, and it is welded together with the rotating shaft 5. The rotary motion of the fuel uniform distribution plate 8 makes the biomass particles evenly distributed in the furnace, and will not be deposited on the central smoke pipe 12 and the cross smoke pipe 9 . The arrangement of the central smoke pipe 12 and the cross smoke pipe 9 enables the flue gas to recirculate in the furnace. There are three return journeys, and each return journey is axisymmetrically distributed in the furnace, so that the temperature field in the furnace is evenly distributed.

The radiation guide block 10 is made of refractory material, and its relative installation position with the working cross smoke pipe 9 is shown in Figure 3, and it is inlaid on the furnace 7. The design of this structure is mainly to increase the preheating residence time of biomass particles , increase the radiation heat transfer of the furnace.

The fully preheated biomass particles meet the air preheated by the air preheater sent by the segmented air nozzles 11 arranged in the lower part of the furnace 7 in a segmental tangential upward direction (with an elevation angle of 5-80°). Realize high temperature, swirl, classification, high temperature combustion. The number of nozzles can be adjusted according to the feed amount of biomass particles, and the excess air coefficient is strictly controlled to improve the combustion. The number of nozzles can be adjusted according to the feed amount of biomass particles, and the excess air coefficient is strictly controlled to improve the thermal efficiency of the boiler.

The cyclone separator 13 is made of heat-resistant ceramic material. The upper end surface and the vertical direction are inclined downward by 150-160° to prevent the deposition of liquid ash. There are two tangential inlets, which are symmetrically distributed to prevent liquid ash, dust, and smoke Entering tangentially, the separation is realized in the cyclone separator 13. The high-temperature flue gas is discharged from the top of the furnace 7 through the central smoke pipe 12 and the cross smoke pipe 9. The liquid ash and dust pass through the slag discharge port 14 to the liquid slag discharge tank 15.

The high-temperature flue gas discharged from the top of the furnace 7 by the central smoke pipe 12 and the cross pipe 9 flows through the annular gap formed by the furnace 7 and the furnace wall 17, and exchanges heat with the furnace again, preheats the biomass particles, and cools the furnace. The combustion chamber in the bile 7 plays a role of heat preservation and improves the combustion temperature of biomass. The high-temperature flue gas then enters the flue gas secondary outlet 18 below the furnace wall 17. The flue gas pipe 22 of the steam generating chamber exchanges heat with the water entering the steam generating chamber through the water inlet 21. The partition plate 19 and the baffle chamber 23 make the flue gas After flowing through the flue gas pipe 22 for two return journeys, the flue gas is discharged from the tertiary outlet 20 to the conventional air preheater to exchange heat with the combustion air, and finally discharged from the chimney through the flue and induced draft fan.

According to the characteristics of the biomass briquette fuel, the present invention adopts a unique structure to pre-dry the biomass particles, the feed and high-temperature flue gas are evenly distributed, and the high-temperature combustion of the biomass particles is realized, and the cyclone separator is transplanted to the bottom of the furnace to realize High temperature dust removal. The biomass high-temperature boiler designed with this structure not only has the advantages of high combustion efficiency and uniform temperature field distribution in the furnace, but also has low soot content, nitrogen oxides and sulfur dioxide content in the exhaust smoke, which meets the requirements of the national boiler pollutant emission standard. Solve the current technical problems of direct combustion of biomass.

Claims (6)

1, a kind of biomass high temperature combustion boiler, boiler body comprises flue (7), furnace wall (17), smoke pipe (22), it is characterized in that: the biological particles feed arrangement that motor (1), shaft coupling (2), charging aperture (3), hopper (4), rotating shaft (5), helical blade (6), fuel uniform board (8), hopper steam outlet (25) constitute is installed in the body of heater top; The preheating chamber that flue (7) and furnace wall (17) are formed carries out preheating in hopper (4) outside to living beings; The steam that the moisture of biological particles is generated by thermal evaporation is discharged by hopper steam outlet (25); Flue (7), radiation baffle (10), segmentation wind nozzle (11) are formed the combustion chamber, link to each other with the biological particles feed arrangement; The flue gas lime-ash discharger that cyclone separator (13), center smoke pipe (12), cross smoke pipe (9), slag tap pond (15) are formed, below link to each other with the combustion chamber; The steam generating chamber that dividing plate (19), smoke pipe (22), baffling chamber (23) are formed, and keep apart by furnace wall (17) between the combustion chamber; Flue (7) is arranged in the body of heater, be inlaid with radiation baffle (10) and segmentation wind nozzle (11) on the inwall, the below connects the urceolus of cyclone separator (13); Center smoke pipe (12) is at flue (7) center, and the bottom connects the top outlet of cyclone separator (13), and the top connects cross smoke pipe (9), forms discharge flue.

2, biomass high temperature combustion boiler as claimed in claim 1 is characterised in that hopper (4) is fixed on the top of flue (7), and the conical surface angle of hopper (4) becomes 30～45 ° obliquely with horizontal line, and there is the throat of 25～35mm the lower end.

3, biomass high temperature combustion boiler as claimed in claim 1 is characterised in that segmentation wind nozzle (11) is faced upward to penetrate tangential segmentation and be arranged in below in the flue (7) that the elevation angle is 5～80 °.

4, biomass high temperature combustion boiler as claimed in claim 1 is characterised in that discharge flue is made up of center smoke pipe (12) and cross smoke pipe (9), and high-temperature flue gas is expelled between flue (7) and furnace wall (17) from cross smoke pipe (9).

5, biomass high temperature combustion boiler as claimed in claim 1 is characterised in that radiation baffle (10) is embedded on the flue (7), and in the vertical direction intersects with respect to cross smoke pipe (9) to be placed.

6, biomass high temperature combustion boiler as claimed in claim 1 is characterised in that cyclone separator (13) is installed in the below of flue (7), and the upper surface of cyclone separator (13) becomes tiltedly 150～160 ° down with vertical direction.

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