CN109679705B - Composite fluxing agent for improving coal ash meltability - Google Patents
Composite fluxing agent for improving coal ash meltability Download PDFInfo
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- CN109679705B CN109679705B CN201910046594.2A CN201910046594A CN109679705B CN 109679705 B CN109679705 B CN 109679705B CN 201910046594 A CN201910046594 A CN 201910046594A CN 109679705 B CN109679705 B CN 109679705B
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L9/00—Treating solid fuels to improve their combustion
- C10L9/10—Treating solid fuels to improve their combustion by using additives
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L10/00—Use of additives to fuels or fires for particular purposes
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Abstract
The invention discloses a composite fluxing agent for improving coal ash meltability, which belongs to the technical field of improving coal ash meltability and can solve the problems that the existing method for improving coal ash meltability has high cost, reduces ash melting point, and cannot adjust the viscosity-temperature characteristic of coal ash, and the like, wherein the fluxing agent raw materials comprise readily available industrial raw materials such as limestone, iron ore, silica sand and the like, the silica sand is mainly used for adjusting the silica-alumina ratio of target coal types, the adding proportion is determined according to the ash components of the target coal types, and the adding amount accounts for 4-6% of the mass of raw coal. The invention effectively improves the fusibility of the coal ash, can ensure the requirement of mixing uniformity and can meet the requirements of environmental protection and stable production.
Description
Technical Field
The invention relates to the technical field of improving coal ash meltability, in particular to a composite fluxing agent for improving coal ash meltability.
Background
With the maturity and rapid popularization and application of the types of furnaces including aerospace furnaces, Jinhua furnaces and the like in China, the research and development direction and the market of coal gasification are gradually dominated by large pressurized entrained flow coal gasification gasifiers, and the popularization and application of liquid slag removal gasifiers limit the use of high ash fusion point coal in a certain sense.
Because most of the gasification furnaces which are operated at home at present adopt a liquid slag discharging mode, the ash melting point and the viscosity-temperature characteristic are very important for the slag discharging process of the gasification furnaces, and the viscosity of the coal ash is reduced along with the over-high temperature in the gasification furnaces, so the coal ash can not be attached to the furnace walls of the gasification furnaces, and the gasification furnaces can not be effectively protected. If the temperature in the gasifier is too low, the viscosity of the coal ash is too high, the coal ash is easy to adhere to the furnace wall and even blocks a slag discharge port, normal slag discharge of the gasifier is affected seriously, and the process is affected by stopping the furnace for cleaning, so that the high-load operation of production is restricted.
In order to meet the requirement of slag tapping of coal with high ash melting point (the flowing temperature of ash is more than 1580 ℃ and exceeds the measurement range of a traditional ash melting point tester), the general operation temperature of the gasification furnace is 50-100 ℃ higher than the ash melting point, and the following problems are mainly caused: 1. the coal pyrolysis gasification is controlled to be above 950 ℃, the temperature is controlled to be higher than 1400 ℃, the temperature space needs to consume a large amount of energy to realize, the operation temperature of the gasification furnace is reduced, and the method is an effective way for reducing the consumption of a coal gasification system; 2. the operation stability of the high-temperature area is poorer, and the safety is lower; 3. the poor viscosity-temperature characteristic can cause the temperature range of the coal ash in a flowing state to be narrow, the range for controlling the process operation is small, the operation difficulty of the gasification furnace is high, the stability is poor, and the furnace shutdown accident of the gasification furnace caused by slag bonding or poor slag wall hanging is easy to happen.
The melting point of the raw material coal ash is reduced by adopting the following modes: adding limestone; secondly, blending coal with better coal ash meltability to carry out coal blending gasification; adding sodium salt; adding magnesium salt or borax and the like. But more problems exist in the production practice, such as the unstable slag adhering problem caused by coal blending; the corrosion problem caused by the dissolution of sodium salt in a grey water system; the effect of magnesium salts is not obvious, which causes the problem of higher ash content. The addition of the calcium flux causes the phenomenon of "extreme" of ash melting point.
Therefore, the technical problem to be solved in the field is to provide a fluxing agent which is simple to operate and difficult to slag, and can adjust the pH ratio of coal ash to reduce the melting point of the coal ash.
Disclosure of Invention
In order to solve the technical problems, the invention provides a composite fluxing agent for improving the meltability of coal ash.
According to one aspect of the invention, a composite fluxing agent for improving the meltability of coal ash is provided, which comprises the following components:
Wherein the ratio of the silicon element to the aluminum element in the composite fluxing agent is 1: 1-3: 1.
Optionally, the following components are included:
Optionally, the following components are included:
Optionally, the composite fluxing agent is in the form of particles, wherein the fraction with a particle size of 3-10mm is greater than 85% and the fraction with a particle size of less than 3mm is less than 10%.
optionally, the composite flux has a water content of less than 5%.
according to another aspect of the invention, the composite fluxing agent is added to raw coal by 4-6%, wherein the addition amount of CaCO3 is 3-3.5% of the mass of the raw coal, and the addition amount of Fe2O3 or Fe3O4 is 2.5-3% of the mass of the raw coal.
Optionally, the coal ash of coal combustion doped with the composite fluxing agent contains 60-80% of acidic oxide component, 20-30% of alkaline oxide component and 2-5.5:1 of acid-base ratio.
Optionally, the coal ash of coal combustion doped with the composite fluxing agent contains 65-75% of the acidic oxide component, 22-25% of the alkaline oxide component and the acid-to-alkaline ratio of 3-5: 1.
The ash melting point and the viscosity temperature characteristic are used as important indexes for coal ash gasification, the ash melting point is the temperature of coal ash when the coal ash is molten, and generally comprises softening, melting and flowing temperature points, wherein the lower the flowing temperature is, the better the coal ash gasification effect is. Only when the melting point of the coal ash is low and the viscosity of the coal ash is low when the melting point is reached, the coal ash is easy to flow, the coal ash is easy to gasify, and the slag of the gasification furnace is easy to discharge. The viscosity-temperature characteristic refers to the fluidity of liquid ash when the ash content of coal is molten at different temperatures.
The composite fluxing agent for improving the coal ash meltability comprises 15-35% of Fe2O3 or Fe3O4, 5-55% of CaCO3, 8-18% of SiO2 and less than or equal to 4% of Al2O 3.
Preferably, the composite fluxing agent for improving the coal ash meltability comprises 15-25% of Fe2O3 or Fe3O4, 45-55% of CaCO3, 8-15% of SiO2 and less than or equal to 2% of Al2O 3.
Of these, CaCO3 is one of the important components of the composite flux of the present invention, and the calcium-based flux has a "pole", and when the flux is added in a certain proportion, the ash melting point does not decrease any more, but rises. The content of CaCO3 in the composite fluxing agent is 35-55%. Preferably, the content of CaCO3 in the composite fluxing agent is 45-55 percent
SiO2 is one of the important components of the composite fluxing agent, the silicon component is the traditional acidic component, but when the silicon content in the target coal ash component is in the range of 45-60%, the silicon can effectively reduce the ash melting point and obviously improve the coal ash viscosity-temperature characteristic; according to the condition of the content of silicon in different raw material coal ash components, the content of SiO2 in the composite fluxing agent is 8-18%, and preferably the content of SiO2 in the composite fluxing agent is 8-15%.
Fe2O3 or Fe3O4 as the iron-based fluxing agent is one of the important components of the composite fluxing agent, the iron-based fluxing agent is convenient to obtain and is in positive correlation with the reduction of ash melting point, but the situation that the slag discharge and the wall hanging are influenced by the precipitation of iron simple substances when the iron-based fluxing agent is doped into the coal ash is easy to occur. Therefore, the content of Fe2O3 or Fe3O4 in the composite fluxing agent is 15-35%, and the content of Fe2O3 or Fe3O4 in the composite fluxing agent is 15-25% by comprehensively considering the reduction of ash melting point and the condition of wall hanging.
The content of Al2O3 used as an element affecting the adjustment of ash melting point should be controlled, and according to the earlier data, the effect of Fe2O3 of about 2-3% can be counteracted when the content of Al2O3 is increased or decreased by 1%. According to the empirical estimation, the invention requires that Al2O3 is less than or equal to 4 percent.
The viscosity-temperature characteristic of the molten slag generated by raw coal combustion mainly depends on the viscosity of the liquid slag, the viscosity of the liquid slag depends on the composition of the slag, particularly the content of SiO/Al2O3, CaO and FeO, and in the actual gasification application, a fluxing agent needs to be added to improve the melting characteristic and the viscosity-temperature characteristic of the coal ash so as to meet the operation requirement of the industrial liquid slag-off gasification furnace. According to the invention, the silicon-aluminum ratio is adjusted by adding silicon dioxide, the iron and calcium are added, the content of alkaline components is improved, and finally the ash component of the raw material coal entering the furnace is close to the ash component ratio of the coal with low ash melting point, so that the aim of reducing the ash melting point is fulfilled. The silicon-aluminum ratio of the composite fluxing agent is 1: 1-3: 1.
The composite fluxing agent is added into the raw coal by 4-6% when in use, and the composite fluxing agent is added into the raw coal with different component contents by performing experiments on the first ten raw coals with the highest domestic use amount at present, and when the addition amount is 4-6%, the comprehensive effect of reducing the coal ash melting points of different raw coals is the best, and the universality is higher.
As a preferred example of the present invention, the composite flux for improving the melting property of the coal ash comprises the following components:
The invention has the following beneficial effects:
1. The composite fluxing agent for improving the meltability of the coal ash has obvious effect of reducing the melting point of the coal ash, and reduces the ash melting point by about more than 100 ℃ compared with the conventional fluxing agent.
2. The composite fluxing agent for improving the coal ash meltability effectively improves the phenomenon that the ash melting point of the conventional calcium fluxing agent does not decrease or increase reversely along with the increase of the addition amount.
3. The composite fluxing agent disclosed by the invention effectively improves the viscosity-temperature characteristic of the coal ash by selecting a reasonable silicon-aluminum ratio, optimizes the process operation space of the gasification furnace, improves the wall-hanging condition of coal combustion, and prevents the occurrence of conditions that the production cycle is influenced by the fact that the coal ash needs to be shut down and cleaned and the like due to slagging.
4. The composite fluxing agent provided by the invention fully considers the problem of stable metering in the coal burning process, has uniform granularity and good fluidity, and can ensure continuous, stable, accurate and reliable quantitative control of small dosage.
5. the composite fluxing agent is added into raw coal, so that the ash component of the raw coal entering the furnace is close to the ash component proportion of coal with low ash melting point, the ash melting point is reduced, the viscosity-temperature characteristic of coal ash is improved, and the operation stability of the gasification furnace is improved.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. It should be noted that, in the embodiments and examples of the present application, the feature vectors may be arbitrarily combined with each other without conflict.
A composite fluxing agent for improving coal ash meltability comprises the following components: fe2O3 or Fe3O 415-35%, CaCO 335-55%, SiO 28-18%, and Al2O3 not more than 4%. The ratio of silicon element to aluminum element in the composite fluxing agent is 1: 1-3: 1, under the condition, the ash component of the raw coal entering the furnace is close to the ash component ratio of coal with low ash fusion point, the purpose of lowering the ash fusion point is achieved, and the problems that due to the poor viscosity-temperature characteristic of coal ash, the temperature is lowered and the viscosity is increased in the process that slag flows downwards from a slag hole, slag is attached and difficult to flow, gas drift is caused by slag attachment, a downcomer is bonded or burnt through, and the downcomer has to be overhauled after each furnace shutdown are solved.
The composite fluxing agent is granular, wherein the part with the grain diameter of 3-10mm is more than 85 percent, and the part with the grain diameter of less than 3mm is less than 10 percent. The water content of the composite fluxing agent is less than 5 percent.
the use method of the composite fluxing agent for improving the coal ash meltability comprises the step of adding 4-6% of the composite fluxing agent into raw coal, wherein the adding amount of CaCO3 is 3-3.5% of the mass of the raw coal, and the adding amount of Fe2O3 or Fe3O4 is 2.5-3% of the mass of the raw coal.
The coal ash burnt by coal doped with the composite fluxing agent contains 60-80% of acidic oxide components, 20-30% of alkaline oxide components and the ratio of acid to alkali is 2-5.5: 1.
The coal ash burnt by coal doped with the composite fluxing agent contains 65-75% of acidic oxide components, 22-25% of alkaline oxide components and the ratio of acid to alkali is 3-5: 1.
Specific examples of the composite flux of the melting property of the fly ash are listed below, and in the examples of the present invention, the raw materials are limestone, iron ore, and silica sand.
Examples
Table 1 shows some examples of specific contents of each component in the composite flux for improving the melting property of coal ash according to the present invention. It should be noted that the specific contents of the components of the coal ash melting composite fluxing agent of the present invention are not limited to the data in table 1.
table 1 examples of composite flux component contents
Comparative test example
The performance of the composite fluxing agents of examples 1-8 that improve the meltability of the coal ash was tested. Meanwhile, the performance data of coal combustion by adopting the common calcium fluxing agent in the prior art are compared, and are specifically shown in table 2.
Table 2 composite fluxing agent performance testing and comparative ash melting point results for improved coal ash meltability
As can be seen from Table 2, the melting point of the coal ash added with the flux of the present invention is significantly lower than that of the conventional calcium flux. The calcium fluxing agent is used only, the average value of the flow temperature of the raw material coal is 1387 ℃, the average value of the flow temperature of the raw material coal can be effectively controlled to 1308 ℃ by using the fluxing agent, and no process shutdown accidents occur in the process of using the fluxing agent.
As can be seen from Table 2, the optimal range of SiO2 in the fluxing agent is 9.60-17.72%; the optimal range of Fe2O3 is 16.91-20.77%; the optimum range of CaCO3 is 38.00% -51.25%. Considering the limitations of all coal types, the optimal component proportion of the fluxing agent is as follows: the optimal range of SiO2 is 8.00% -18.00%; the optimal range of Fe2O3 is 15.00-25.00%; the optimum range of CaCO3 is 35.00% -55.00%.
In summary, the composite fluxing agent for improving the coal ash meltability provided by the invention is prepared by adjusting the components and the proportion, selecting a proper silica-alumina ratio, and reducing the pH ratio of coal ash for coal combustion, so that the viscosity-temperature characteristics of the coal ash are effectively improved, and the number of days for stable operation of the gasification furnace is prolonged.
It is to be noted that, in this document, the terms "comprises", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion, so that an article or apparatus including a series of elements includes not only those elements but also other elements not explicitly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of additional like elements in the article or device comprising the element.
The above embodiments are merely to illustrate the technical solutions of the present invention and not to limit the present invention, and the present invention has been described in detail with reference to the preferred embodiments. It will be understood by those skilled in the art that various modifications and equivalent arrangements may be made without departing from the spirit and scope of the present invention and it should be understood that the present invention is to be covered by the appended claims.
Claims (1)
1. The use method of the composite fluxing agent for improving the meltability of the coal ash is characterized in that the composite fluxing agent takes limestone, iron ore and silica sand as raw materials and comprises the following components: Fe2O317.95%, CaCO349.94%, SiO211.08%, and Al2O3 not more than 2%, wherein the ratio of silicon element to aluminum element in the composite fluxing agent is 1: 1-3: 1, the composite fluxing agent is granular, wherein the part with the grain size of 3-10mm is more than 85%, and the part with the grain size of less than 3mm is less than 10%; the water content of the composite fluxing agent is less than 5%; adding 4-6% of the composite fluxing agent into raw coal; the coal ash burnt by coal doped with the composite fluxing agent contains 65-75% of acidic oxide components, 22-25% of alkaline oxide components and the ratio of acid to alkali is 3-5: 1.
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| CN110396448A (en) * | 2019-07-12 | 2019-11-01 | 赵夕文 | It is a kind of modified coal-fired |
| CN111748396A (en) * | 2020-06-05 | 2020-10-09 | 中节能（连云港）清洁技术发展有限公司 | Coke inhibitor and preparation method and application thereof |
| CN113416806B (en) * | 2021-05-25 | 2022-11-18 | 鞍钢股份有限公司 | Fusing agent for improving melting property of coal ash for blast furnace blowing and using method thereof |
| CN115261097B (en) * | 2022-09-06 | 2024-01-19 | 山西潞安煤基清洁能源有限责任公司 | Preparation method of raw material coal fluxing agent of liquid slag-discharging gasifier |
| CN115261098A (en) * | 2022-09-06 | 2022-11-01 | 山西潞安煤基清洁能源有限责任公司 | Coal ash composite fluxing agent and method for improving coal ash meltability |
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| CN104479794B (en) * | 2014-10-24 | 2016-03-30 | 东方电气集团东方锅炉股份有限公司 | A kind of fusing assistant and using method thereof reducing gasified pulverized coal slag ash fusion point temperature |
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Effective date of registration: 20220314 Address after: 048021 south side of courtyard 1, Zhengbei street, liushudi village, Xiacun Town, Zezhou County, Jincheng City, Shanxi Province Patentee after: Shanxi Qiwang mineral products Co.,Ltd. Address before: 067512 group 1, copper mine community, nan50jiazi Town, Pingquan City, Chengde City, Hebei Province Patentee before: PINGQUAN TENGJU NONMETAL MINERAL PRODUCTS MANUFACTURING Co.,Ltd. |