CN115682014A - Compound multi-region coal distribution method for boiler - Google Patents
Compound multi-region coal distribution method for boiler Download PDFInfo
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- CN115682014A CN115682014A CN202110873305.3A CN202110873305A CN115682014A CN 115682014 A CN115682014 A CN 115682014A CN 202110873305 A CN202110873305 A CN 202110873305A CN 115682014 A CN115682014 A CN 115682014A
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Abstract
The invention discloses a compound multi-zone coal distribution method for a boiler, which comprises the following steps of S1: arranging and distributing a plurality of coal mills in a boiler furnace, and dividing the boiler furnace into a plurality of layer areas from bottom to top; step S2: pre-blending the coal types according to the quality indexes of the coal types to obtain a plurality of blended coals with different quality indexes; and step S3: adding the blended coal to each layer region to form coal as fired, wherein the quality index of the coal as fired changes in the layer region by layer region; and step S4: and respectively processing the coal as fired by the coal mills in each layer area, and completing combustion. The compound multi-zone coal blending method disclosed by the invention is used for carrying out coal blending combustion, and has a better effect on the aspects of ensuring the environmental protection, safety and economic operation of boiler combustion. The adaptability of the boiler to various different coal types is widened, the combustion safety of the boiler is ensured to the maximum extent when the large proportion of the inferior coal types are mixed and burned, and the risk resistance of a combustion system of the boiler under various abnormal working conditions is greatly improved.
Description
Technical Field
The invention relates to the technical field of coal blending, in particular to a compound multi-zone coal blending method for a boiler.
Background
In recent years, due to the change of coal markets, the supply of fire coal is in short supply, the price of power generation coal is continuously increased, the fuel cost accounts for about 70% of the power generation cost of thermal power generation enterprises, the coal types arriving at a factory are increased, the coal quality is reduced, a plurality of coal types are seriously deviated from the designed coal types of boilers, the problems of unstable boiler combustion, reduced power generation efficiency, incapability of full generation and the like are caused, and the normal operation of a unit is seriously influenced. Therefore, how to reasonably blend the inferior coal and reduce the power generation cost under the condition of ensuring the combustion requirement of the boiler becomes the core problem of the survival and the development of each power generation enterprise, and the coal blending and coal yard management work of the power plant also faces new challenges.
The prior solution is that a single coal type is used for coaling all coal bunkers, the coal types burned by all coal mills of a boiler are the same, or the high-quality coal and the low-quality coal are mixed to coale all the coal bunkers by utilizing the additive characteristics of parameters such as ash content, volatile components, sulfur content, moisture, heat productivity and the like of the coal types, and the coal types burned by all the coal mills of the boiler are the same.
However, this solution has the following disadvantages:
(1) Because the coal quality of the coal entering the plant is basically deviated, single coal type is basically high in ash, water, carbon, sulfur, volatile matters, calorific value and too viscous, the single coal type is continuously combusted for a long time, so that the safety of the boiler is reduced, the economical efficiency of a power plant is not high, and meanwhile, the flexibility of the coal blending mode of the single coal type is insufficient, and the adjustment requirements of various working conditions of the boiler cannot be met;
(2) By adopting the method of feeding coal to all coal bins after premixing before the boiler, when the premixing is not uniform, the steam temperature, the pressure, the steam drum water level hearth negative pressure and other parameters of the boiler are easy to fluctuate frequently, the safe operation of the boiler is influenced, and the advantages of various coal types cannot be effectively exerted for utilization;
(3) The high-sulfur coal is an economic coal type with higher sulfur content, according to the previous blending combustion mode, the high-sulfur coal and the low-sulfur coal are blended and combusted according to a certain proportion, the sulfur content of the coal as fired is controlled to be below the design parameters of a boiler so as to meet the requirement of environmental protection on desulfurization indexes, and the blending combustion method has the advantages that the consumption of the high-sulfur coal is lower, the consumption of the low-sulfur coal is higher, and the full-load operation is not fully realized by utilizing the treatment capacity of a desulfurization tower.
Disclosure of Invention
In order to solve the technical problem, the invention provides a compound multi-zone coal blending method for a boiler.
A compound multi-zone coal distribution method for a boiler comprises the following steps:
step S1: arranging and distributing a plurality of coal mills in a boiler furnace, and dividing the boiler furnace into a plurality of layer areas from bottom to top;
step S2: pre-blending the coal types according to the quality indexes of the coal types to obtain a plurality of blended coals with different quality indexes;
and step S3: adding the blended coal to each layer region to form coal as fired, wherein the quality index of the coal as fired changes from layer to layer in the layer regions;
and step S4: and respectively processing the coal as fired by the coal mills in each layer area, and completing combustion.
Preferably, in the step S2, the quality index includes one or more of a safe combustion coefficient, an environmental protection coefficient, and an economic coefficient; the safe combustion coefficient comprises various comprehensive evaluations in the heat value, the volatile value, the moisture value, the ash fusion point value, the carbon content, the viscosity and the fluidity of the coal; the environment protection coefficient comprises various comprehensive evaluations in the volatility value, the sulfur content and the moisture value of the coal; the economic coefficient comprises various comprehensive evaluations in unit price, stock number, heating efficiency and mixing proportion of the coal.
Preferably, in the step S1, the coal mill is divided into N zones, where N is not less than 2, and the zones are 1 zone to N zone from bottom to top, and each zone is configured with a plurality of coal mills.
Preferably, in step S3, the safe combustion coefficient of the coal as fired is higher in the zone 1 than in the other zones.
Preferably, in step S3, the safe combustion coefficient of the coal as fired decreases from bottom to top of the zone, and is highest in the zone 1 and lowest in the zone N.
Preferably, in step S3, the environmental protection factor of the coal as fired is lower in the zone 1 than in the other zones.
Preferably, in the step S3, the environmental protection coefficient of the coal as fired is increased in the zone from bottom to top, and is lowest in the zone 1 and highest in the zone N.
Preferably, the N is 3, the zone 1 is a high sulfur zone, the zone 2 is a medium sulfur zone, and the zone 3 is a low sulfur zone; in the high-sulfur zone and the middle-sulfur zone, the sulfur content of the coal as fired is 1.1-1.2% by mass; in the low-sulfur area, the sulfur content of the coal as fired is 0.2-0.3% by mass percent.
Preferably, in the high-sulfur zone, the middle-sulfur zone, and the low-sulfur zone, the average sulfur content of the coal as fired is 0.87 mass% or less.
Preferably, in the step S2, the coal includes one or more of upmix, shenmix, itai, huaneng mix, montreal mix, columbia coal, domestic coal, indonesia coal and brown coal.
The implementation of the invention has the following beneficial effects:
the compound multi-region coal blending method is used for blending combustion of the coal, and has good effects on ensuring environmental protection, safety and economic operation of boiler combustion. The adaptability of the boiler to various different coal types is widened, the combustion safety of the boiler is ensured to the maximum extent when the large proportion of the inferior coal types are mixed and burned, and the risk resistance of a combustion system of the boiler under various abnormal working conditions is greatly improved. Meanwhile, the efficiency of the boiler is improved by more than 1 percent compared with other coal blending modes.
Drawings
FIG. 1 is a schematic structural diagram of a first embodiment of the present invention;
fig. 2 is a schematic structural diagram of a second embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.
Example one
As shown in FIG. 1, a compound multi-zone coal distribution method for a boiler divides a boiler furnace into an upper zone and a lower zone, for example, 4 zones, each zone is added with coal with different coal qualities, and each zone is premixed and added with one or two different coal types. Preferably, the burning powder process system adopts five medium speed coal mills for cold wind malleation directly blows the system, and the tangent circle combustion system is arranged in the four corners, regards two coal mills of lower floor as 1 district (lower region), and 3 coal mills are distinguished as last in addition, and the coal blending is respectively distinguished, and when arbitrary coal mill breaks down in last district or lower region, it is less to the influence of boiler burning, is difficult for taking place to put out a fire. When blending and burning the blended coal, blending and blending the blended coal according to the principles of old and new burning, high and low heat value coal blending, high and low sulfur content coal blending, high and low volatile component coal blending and high and low moisture content coal blending, the blended coal sequentially considers an environmental protection coefficient, a safety coefficient and an economic coefficient, the environmental protection coefficient is obtained by calculating the volatile value, the sulfur content value and the moisture content value of the blended coal, the safety coefficient is obtained by calculating the heat generation value, the volatile value, the sulfur content value, the moisture content value and the ash fusion point value of the blended coal, the economic coefficient is obtained by calculating the heat generation value of the blended coal and the blending proportion, unit price and inventory number of each coal, so that the coal quality of the blended coal is as close to the designed coal of the boiler as possible, and the safe burning of the boiler is ensured as much as possible.
The lower area is mainly stable combustion, coal types such as high heat value and carbon content, low volatile component and moisture, excellent mixing, magical mixing, itai, huaneng mixing, mongolian mixing and Columbia coal and the like are blended with coal types such as Indonesian coal and the like with low heat value and high volatile component and moisture, and then are matched in the lower area, the smoke exhaust temperature and fly ash combustible matter are greatly reduced compared with equal blending combustion, the combustion efficiency of the boiler is improved, when a unit has abnormal working condition load shedding, the coal quality of two coal mills in the lower area is relatively good, and the lower area plays an important role in preventing the fire extinguishing of the boiler; the upper area mainly consumes inferior coal, and domestic coal is blended with Indonesian coal, single-burned Indonesian coal or two Indonesian coals, or partial lignite can be blended. Wherein the Indonesia coal has the general characteristics of low heat value, large water content, large viscosity and poor fluidity (Qnet, ar:16-21MJ/kg, mar:18-28%, aar:2.5-12%, vdaf:45-52% and FCar: 33-38%), and the Indonesia coal with the proportion of 50% or more can be blended in the lower region. And the upper area adopts single-burning Indonesian coal or two types of Indonesian coal to blend, so that the consumption of Indonesian coal can be greatly increased, the management work of a coal yard is facilitated, the storage time of high-volatile easy-spontaneous-combustion coal types such as Indonesian coal and the like in the coal yard is reduced, the spontaneous combustion of the coal yard is prevented, the loss of the coal yard is reduced, and the difference of heat values of coal entering the factory and coal entering the furnace can be reduced to the maximum extent. Under the condition that domestic coal is distributed at the lower part, ignition of the plasma mill is facilitated when abnormal stopping occurs, and oil for starting is reduced. This coal blending mode carries out various coal blending combinations in a flexible way under the unchangeable condition of big frame, and furnace flame central temperature is higher relatively, all has the improvement to boiler security and combustion efficiency, and when having any coal pulverizer to break down in upper district or lower district, boiler safety burning receives the influence lessly, becomes ordinary combustion system into the strong combustion system that can more resist various interior outer disturbances.
Specifically, the compound multi-region coal blending method of the boiler can avoid coal feeding in different time periods, avoids the defect that the coal feeding in different time periods is greatly influenced by loads, can be accurately controlled, does not easily generate serious overpressure and overtemperature during coal type conversion, does not need to continuously adjust a coal blending scheme according to the conditions of various coal mills during operation, reduces the error probability, and has better effect.
Example two
As shown in figure 2, the compound multi-zone coal blending method for the boiler divides a coal mill in a boiler hearth into a high zone, a medium zone and a low-sulfur zone or a high zone and a low-sulfur zone from bottom to top, and flexibly blends coal according to the existing coal storage condition. Coal with the sulfur content of 1.1-1.2% by mass is added to a high-sulfur area and a middle-sulfur area, coal with the sulfur content of 0.2-0.3% by mass is added to the low-sulfur area, and the total sulfur content of the coal as fired is still controlled below 0.87%, so that the sulfur exceeding caused by instant high load is prevented. Under the condition that the load capacity of the boiler is not more than 70 percent, the coal mill in the high-sulfur and middle-sulfur areas is operated, high-sulfur coal can be continuously and rapidly consumed for 24 hours, the consumption of the high-sulfur coal is about more than 3 times of the original consumption, the consumption of the low-sulfur coal is greatly reduced, the high-sulfur coal can be rapidly consumed in the whole boiler, the fuel conservation and the supply are facilitated, and the environmental protection emission requirement is metIn addition, the method has considerable economic benefit; meanwhile, the flow rate of the flue gas is slow at medium and low loads, and the raw flue gas SO 2 Concentration is high, promotes with limestone reaction efficiency, and limestone utilization efficiency promotes, and the higher limestone consumption of every kilowatt-hour electric quantity of desulfurizing tower efficiency reduces, saves the cost, and the average sulphur content can exceed the desulfurization design value by a wide margin, and desulfurization system still can normal operating, simultaneously, can consume high sulphur coal fast, reduces low sulphur coal consumption, greatly increased gypsum output.
It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All modifications made in accordance with the spirit of the main technical scheme of the invention are intended to be covered by the scope of the invention.
Claims (10)
1. A compound multi-zone coal distribution method for a boiler is characterized by comprising the following steps:
step S1: arranging and distributing a plurality of coal mills in a boiler furnace, and dividing the boiler furnace into a plurality of layer areas from bottom to top;
step S2: pre-blending the coal types according to the quality indexes of the coal types to obtain a plurality of blended coals with different quality indexes;
and step S3: adding the blended coal to each layer region to form coal as fired, wherein the quality index of the coal as fired changes from layer to layer in the layer regions;
and step S4: and respectively processing the coal as fired by the coal mills in each layer area, and completing combustion.
2. The compound multi-zone coal blending method for the boiler according to claim 1, wherein in the step S2, the quality index comprises one or more of a safe combustion coefficient, an environmental protection coefficient and an economic coefficient; the safe combustion coefficient comprises various comprehensive evaluations in the heat value, the volatile value, the moisture value, the ash fusion point value, the carbon content, the viscosity and the fluidity of the coal; the environment protection coefficient comprises various comprehensive evaluations in the volatile value, the sulfur content and the moisture value of the coal; the economic coefficient comprises various comprehensive evaluations in unit price, stock number, heating efficiency and mixing proportion of the coal.
3. The compound multi-zone coal blending method for the boiler according to claim 2, characterized in that in the step S1, N zones are divided, wherein N is not less than 2 and ranges from 1 zone to N from bottom to top, and each zone is provided with a plurality of coal mills.
4. The compound multi-zone coal blending method for the boiler according to claim 3, wherein in the step S3, the safe combustion coefficient of the coal as fired is higher in the zone 1 than in the other zones.
5. The compound multi-zone coal blending method for the boiler according to claim 4, wherein in the step S3, the safe combustion coefficient of the coal as fired is reduced from bottom to top of the zone, is highest in the zone 1, and is lowest in the zone N.
6. The compound multi-zone coal blending method for the boiler according to claim 3, wherein in the step S3, the environmental protection factor of the coal as fired is lower in the zone 1 than in the other zones.
7. The compound multi-zone coal blending method for the boiler according to claim 6, wherein in the step S3, the eco-factor of the coal as fired is increased from bottom to top in the zone by zone, is lowest in the zone 1, and is highest in the zone N.
8. The compound multi-zone coal blending method for the boiler according to claim 7, wherein N is 3, the zone 1 is a high sulfur zone, the zone 2 is a middle sulfur zone, and the zone 3 is a low sulfur zone; in the high-sulfur zone and the middle-sulfur zone, the sulfur content of the coal as fired is 1.1-1.2% by mass; in the low-sulfur area, the sulfur content of the coal as fired is 0.2-0.3% by mass percent.
9. The compound multi-zone coal blending method for the boiler according to claim 8, wherein the average sulfur content of the coal as fired in the high-sulfur zone, the middle-sulfur zone and the low-sulfur zone is 0.87 mass% or less.
10. The multi-zone coal blending method for the boiler according to claim 1, wherein in the step S2, the coal types include one or more of a group consisting of a prime mix, a magic mix, ita, a Huaneng mix, a Mongolian mix, a Columbia coal, a national coal, indonesian coal and lignite.
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| CN202110873305.3A CN115682014A (en) | 2021-07-30 | 2021-07-30 | Compound multi-region coal distribution method for boiler |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117404678A (en) * | 2023-10-23 | 2024-01-16 | 国能长源荆门发电有限公司 | Online coal blending system for relieving slag formation of high-alkali coal burned by boiler |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117404678A (en) * | 2023-10-23 | 2024-01-16 | 国能长源荆门发电有限公司 | Online coal blending system for relieving slag formation of high-alkali coal burned by boiler |
| CN117404678B (en) * | 2023-10-23 | 2024-05-31 | 国能长源荆门发电有限公司 | Online coal blending system for relieving slag formation of high-alkali coal burned by boiler |
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