CN1240902A

CN1240902A - Method for improving combustion of industrial boiler

Info

Publication number: CN1240902A
Application number: CN 99103741
Authority: CN
Inventors: 张大力; 张大雷
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-23
Filing date: 1999-03-23
Publication date: 2000-01-12

Abstract

A method for improving the combustion of industrial boiler including grate-fired boiler or torch-grate boiler features that raw coal is separated by airflow to obtain coarse and fine coal particles. The coarse coal particles directly burns in proir industrial boiler. Said fine coal particles are ground and separated to obtain qualified fine coal powder, which burns in the combustion box of powdered coal burner. Its advantages are less loss of coal, full combustion, high efficiency and no black smoke generation.

Description

Improve the method for combustion of industrial boiler

The invention relates to the method for improving combustion of industrial boiler, be particularly suitable for grate furnace and torch-grate furnace in the Industrial Boiler.

At present, it is very high to be applied in the raw coal in the Industrial Boiler duff grain ratio.For example, certain coal, particle diameter accounts for 28.5% less than the percentage by weight of 1 millimeter coal grain, and particle diameter accounts for 30.2% at the coal grain percentage by weight of 1-4 millimeter, particle diameter accounts for 41.3% greater than 4 millimeters coal grain percentage by weight, and visible particle diameter accounts for 58.7% less than 4 millimeters duff grain percentage by weight.Coal mainly burns on fire grate in the grate furnace, and the burning required air enters by under the fire grate, passes fire grate slit, coal seam and coal catalytic combustion.Operation has following influence to duff grain ratio to grate furnace greatly in the coal: 1, increase from fire grate slit source coal, for fire grate wearing and tearing after the long-time running ventilation gap is increased, this situation is more serious.2, the duff grain is embedded between the coarse coal, it is very solid that pile easily in the coal seam, make heat be difficult for passing to the depths, coal seam, simultaneously the steam in the dry run is difficult for again being evaporated: cause the coal seam difficulty of catching fire on the one hand, cause that on the other hand the coal bed ventilation resistance increases, the ventilation skewness, coal combustion is insufficient, causes the slag burn-out degree poor.3, make the coal seam produce burner easily, it is poor that the duff grain is blown afloat the floating flying dust burn-out degree that causes, the chimney over-emitting black exhaust.The present principal mode of torch one grate furnace is a spreader stoker boiler.In coal is thrown into stove, duff grain suspension combustion in burner hearth, the rough coal grain drops on the fire grate and burns.The suspension combustion that forms in the dried spreader stoker boliler furnace chamber is different with the coal-powder boiler suspension combustion, because these duff grains are than thick many of coal dust, the needed time ratio coal dust that burns will be grown, and ignition temperature requires also high.When the higher coal of torch-grate furnace burning duff grain ratio, except that the shortcoming with above-mentioned grate furnace, mainly also have following shortcoming: 1, the flying dust amount is big, combustible content height in the flying dust.2, chimney over-emitting black exhaust, serious environment pollution.

The objective of the invention is, with pneumatic separation equipment the duff grain in the coal, rough coal grain are separated, the rough coal grain is thrown on the fire grate with the coal supply equipment of burning usefulness and is burnt, the duff grain selects for use dry gas stream to enter coal pulverizer with branch, in coal pulverizer, grind to form coal dust, enter the meal parting surface with gas then, the defective rough coal powder in separation back returns coal pulverizer and grinds again, qualified fine breeze sprays into the burner hearth burning through coal burner, reach to reduce and leak coal, improve coal seam burn-out degree, flying dust burn-out degree, eliminate the chimney black smoke, reach the purpose of environmental requirement.

The present invention realizes like this, raw coal is delivered on the fire grate through burning with coal supply equipment or is swum in the combustion of industrial boiler equipment of air to fuel ratio in the burner hearth, raw coal selects for use feeder and dry gas together to enter air-classifier through branch earlier, rough coal powder after the sorting is delivered on the fire grate with coal supply equipment through burning and is burnt, duff grain after the sorting enters coal pulverizer with dry gas, in coal pulverizer, be ground into coal dust, enter mill separator with dry gas again, carrying out the thickness powder separates, underproof rough coal powder returns coal pulverizer and grinds again, and qualified fine breeze sprays into the burner hearth burning through coal burner.Thereby solved because the fire grate that the duff grain causes in the raw coal leaks coal, stove layer burn-out degree is poor, the flying dust burn-out degree is poor, the problem of chimney over-emitting black exhaust.

Good effect of the present invention is that raw coal is divided into rough coal grain and duff grain through air-classifier, and big of the ventilation gaps of rough coal grain size ratio fire grate have solved fire grate and leaked the coal problem more; The space of the rough coal intergranular on fire grate is big, and rough coal granulosa flowing resistance is little during burning, and Uniform Ventilation makes on the fire grate coal combustion more even, improves the slag burn-out degree; The coal seam is difficult for forming burner in addition, and the coal grain also is difficult for being blown afloat suspension, reduces the flying dust amount.The duff grain grinds to form coal dust through coal pulverizer, through mill separator, defective rough coal powder returns coal pulverizer and grinds again, qualified fine breeze sprays in the burner hearth through coal burner and burns, advantage is one, qualified fine breeze Free Surface will be greatly, often big tens times are arrived hundred times, and therefore qualified fine breeze is than duff grain easy to burn out, and promptly combustible content is few in the flying dust; Two, qualified fine breeze burns in burner hearth by coal burner, because the burning condition tissue is good, it is stronger to burn, the flame kernel temperature can reach 1200 ℃-1600 ℃, and grate furnace or torch-grate furnace flame kernel temperature is about 1000 ℃, and this has improved the burning condition in coal seam greatly, and be suspended in the burning condition of combustible in the burner hearth, to improve coal seam burn-out degree and flying dust burn-out degree greatly, this improves the heat-transfer effect of boiler heating surface greatly in addition, improves boiler output.Three, because the flying dust burn-out degree improves, chimney will emit white cigarette rather than black smoke, reach environmental requirement.In sum, effect of the present invention is to improve boiler efficiency, improves boiler output, solves the problem of chimney over-emitting black exhaust.

Fig. 1 combustion of industrial boiler flow chart

Fig. 2 pneumatic separation pipe schematic diagram

Specific embodiments of the invention are as follows: one, the equipment relevant with the present invention at first is described, the burning of grate furnace comprises coal (storehouse) bucket, coal flashboard with coal supply equipment (1), and the burning of torch-grate furnace comprises coal (storehouse) bucket, blast table spreader or mechanical spreader feeder, wind-powered machine spreader feeder with coal supply equipment (1); Fire grate (2) can be fixed grate, shake (or upset) fire grate, traveling-grate stoker, vibrating-grate stoker, inclined reciprocating fire grate; It can be screw-type coal distributor that branch is selected feeder (3) for use, also can be scraper plate feeder, vibration feeder; Dry gas (4) can be with the high-temperature flue gas of air blast from burner hearth or flue extraction, also can be the hot-air that comes from boiler air preheater; Pneumatic separation equipment (5) can be a fluid drying separation chamber as shown in Figure 1, it also can be pneumatic separation pipe as shown in Figure 2, promptly the feeder of selecting for use from branch (3) is to burning vertical or tilted tube the coal supply equipment (1), dry gas (4) upwards flows from duct bottom, the feeder that raw coal is selected for use through branch (3) is to the whereabouts, through one section acceleration distance, the duff grain flows out from conduit upper with air-flow, the rough coal grain is fallen burning and is used coal supply equipment (1) lining, the particle diameter difference of the duff grain that requires, air velocity difference, acceleration distance are also different; Coal pulverizer (6) can be the low speed barrel-shaped steel ball mill, also can be medium-speed pulverizer, high speed hammering coal pulverizer, high speed fan coal pulverizer; Coarse grain separator (7) can be a radial mode coarse grain separator, also can be the axialmode mill separator; Coal burner (9) can be a DC burner, also can be turbulent burner, and coal burner arrangement, position can be determined according to chamber structure.Two, specific embodiments of the invention are, raw coal enters pneumatic separation pipe (5) through screw-type coal distributor (3) and from burner hearth with the high-temperature flue gas (4) that air blast aspirates, the rough coal grain that sorting obtains is fallen burning and is delivered to upward burning of fire grate (2) with coal supply equipment (1), the duff grain that flows with dry flue gas enters high speed fan coal pulverizer (6), coal dust through grinding enters mill separator (7) with air-flow, underproof rough coal particle returns high speed fan coal pulverizer (6) and grinds again, and qualified fine breeze is cut the garden mode through DC burner (9) and is sprayed onto in the burner hearth (10) so and burns by four jiaos.

The all Industrial Boilers that utilize the present invention to transform, drier are preferably selected the high-temperature flue gas that utilizes air blast to extract from burner hearth or flue for use, can increase the pressure fan and the induced-draught fan capacity of former boiler like this.

In order to adapt to the variation of boiler output, in time adjust boiler combustion, can increase a feeder (8) at coal pulverizer (6) inlet, adjust the coal-supplying amount of feeder (8), change the coal powder density in the coal burner (9), adapt to the variation of boiler output.

In order to guarantee the safe operation of coal pulverizer (6), at the entrance door (13) of coal pulverizer inlet increase drier (4), cold air door (12) mixes gas air door (11), adjusts the interior temperature of coal pulverizers (6) according to different coals, prevents the coal dust explosion accident.

Claims

Improve the method for combustion of industrial boiler, raw coal is delivered to fire grate (2) through burning with coal supply equipment (1) and is gone up or swim in the combustion of industrial boiler equipment of air to fuel ratio in the burner hearth (10), it is characterized in that, raw coal together enters air-classifier (5) through the feeder (3) that branch is selected for use with dry gas (4) earlier, rough coal grain after the sorting is delivered to fire grate (2) through burning with coal supply equipment (1) and is gone up burning, duff grain after the sorting enters coal pulverizer (6) with dry gas (4), in coal pulverizer (6), grind to form coal dust, enter with dry gas (4) again and carry out the thickness coal dust in the mill separator (7) and separate, underproof rough coal powder returns in the coal pulverizer (6) and grinds again, and qualified fine breeze sprays into burning in the burner hearth (10) through coal burner (9).