KR20200049477A - Additive composition for fouling, slagging and corrosion prevention of biomass co-existence or exclusive boiler using alumina oxide - Google Patents

Abstract

The present invention relates to an additive composition for preventing fouling, slagging and corrosion of a biomass mixtures or boilers using alumina. More specifically, the present invention relates to an additive composition which can effectively suppress the fouling, slagging and corrosion of an inner wall of a thermal power plant boiler by increasing the melting temperature of mineral contained in biomass fuel by using alumina, and optimize the thermal efficiency of a power plant. The additive composition can contain 0.1 to 5 parts by weight of alumina (Al_2O_3) with respect to 100 parts by weight of fuel injected into the biomass mixture or the boiler.

Description

An additive composition for fouling, slagging and corrosion prevention of biomass co-existence or exclusive boiler using alumina oxide

The present invention relates to an additive composition for preventing fouling, slagging and corrosion of a biomass mixture using alumina or a dedicated boiler, and more specifically, using alumina to increase the melting temperature of the inorganic material contained in the biomass fuel, thereby increasing the biomass. It relates to an additive composition capable of effectively suppressing fouling, slagging and corrosion of the inner wall of the boiler and optimizing the thermal efficiency of the power generation facility.

Under the Paris climate agreement, each country is implementing a new and renewable energy activation system to reduce carbon dioxide emissions and expand the market for new and renewable energy and increase competitiveness.

Biomass, such as wood chips, wood pellets, and palm oil shells, is attracting attention as an eco-friendly renewable energy in that it can reduce the amount of CO ₂ generated by reducing sulfur content compared to existing fuels. Accordingly, when mixing biomass with existing fuels, there is a problem of causing local heat imbalance due to a difference in heat generation, reducing thermal efficiency, and consequently increasing power generation costs.

In addition, in the case of biomass mixing, minerals with a low melting point among the ashes contained in the biomass are melted during the combustion process. Slagging and fouling phenomena occur in which these minerals flow and stick to the inner walls of the boiler and heat exchange parts to grow. And, this phenomenon significantly lowers the thermal efficiency of the boiler, interferes with the flow pattern in the combustion furnace, and further causes problems that seriously damage the inner wall of the boiler.

In addition, strong alkali components such as K ₂ O and Na ₂ O included in the biomass have high volatility and short residence period inside the boiler, thereby causing non-uniform combustion and coating the inner wall by reaction with ash in the furnace. There is also a problem of corrosion of metal surfaces, including the inner wall of the boiler, and it is urgent to prepare a solution to the heat imbalance, slagging, fouling, and corrosion problems in the boiler when coal and biomass are mixed. .

As a conventional technique to solve this problem,

In Korean Patent Registration No. 10-1542076, "Combustion additive composition for solid fuel and method for using it", combustion additive for solid fuel containing 0.1 to 20 parts by weight of copper precursor and 10 to 300 parts by weight of magnesium precursor with respect to 100 parts by weight of water The composition is presented,

In Korean Patent Registration No. 10-0642146, "A fuel additive composition that improves cold resistance and prevents slag and effectively removes clinker", 30 to 86.98% by weight of a water-soluble solvent, 5 to 20% by weight of a continuous accelerator, 0.01 to 5% by weight of an stabilizer, and alkali Presenting a fuel additive composition comprising 5 to 25% by weight of a metal compound, 0.01 to 5% by weight of a metal compound and 3 to 15% by weight of a surfactant compound,

In Korean Patent Registration No. 10-1586430, “Pellets and Coal Fuels and Fuel Additive Compositions for Increasing Combustion Rate of Incineration Wastes”, 5 to 15 parts by weight of hydrogen peroxide, 30 to 45 parts by weight of sodium hydroxide, and borax per 100 parts by weight of sodium silicate Presents a fuel additive composition consisting of 1 to 10 parts by weight, 10 to 50 parts by weight of oxygen, 2 to 5 parts by weight of glycerol, 1 to 3 parts by weight of fatty acid ester, 2 to 5 parts by weight of surfactant, and 10 to 30 parts by weight of ceramic ball Doing.

However, all of the above techniques are mechanisms required when inputting a thermal power plant boiler as an additive in a liquid form, and when applied to a biomass boiler, there is a problem that it is difficult to expect an effect.

The present invention is proposed to solve the above problems, by raising the melting temperature of the minerals contained in the biomass fuel by using alumina, an additive in the form of a solid powder, fouling, slagging and corrosion of the inner walls of the biomass boiler. It is an object to provide an additive composition for preventing fouling, slagging and corrosion of a biomass mixture or a dedicated boiler using alumina, which can effectively suppress and optimize the thermal efficiency of a power generation facility.

The additive composition for preventing fouling, slagging and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention for solving the above problems, with respect to 100 parts by weight of fuel injected into the biomass mixture or a dedicated boiler Alumina (Al ₂ O ₃ ) It may include 0.1 to 5 parts by weight.

In addition, it may further include 0.1 to 5 parts by weight of coal ash as a by-product of the thermal power plant.

In addition, in aluminum smelting, the silica containing Al ₂ O ₃ , which is a residue obtained by extracting alumina from bauxite by the Bayer method, may further contain 0.1 to 10 parts by weight based on 100 parts by weight of the fuel.

The additive composition for preventing fouling, slagging and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention increases the melting temperature of inorganic substances contained in the biomass fuel, thereby fouling and slaving the inner wall of the biomass boiler. It has the effect of effectively suppressing ging and corrosion and optimizing the thermal efficiency of power generation facilities.

1 is a graph of potassium content in fly ash and bottom ash according to the elapsed days after the addition of the additive composition for preventing fouling, slagging and corrosion.
Figure 2 shows the tube shape in the boiler before the additive composition for preventing fouling, slagging and corrosion.
Figure 3 shows the tube shape in the boiler after the additive composition for preventing fouling, slagging and corrosion.

Hereinafter, the description of the present invention with reference to the drawings is not limited to a specific embodiment, and various conversions may be applied and various embodiments may be provided. In addition, it should be understood that the contents described below include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention.

In addition, the singular expression used in the present invention includes a plural expression unless the context clearly indicates otherwise. In addition, terms such as “include”, “have” or “have” described below are intended to indicate that there are features, numbers, steps, operations, components, parts, or combinations thereof described in the specification. It should be interpreted and understood to not preclude the existence or addition possibility of one or more other features, numbers, steps, actions, components, parts or combinations thereof.

In addition, in describing the principle according to the embodiment of the present invention, when it is determined that the detailed description of the related known technology or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

Hereinafter, the additive composition for preventing fouling, slagging, and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention will be described in detail.

The additive composition for preventing fouling, slagging and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention is based on alumina (Al ₂ O ₃ ) 0.1 to 5 parts by weight may be added.

Here, when the content of alumina is less than 0.1 parts by weight compared to 100 parts by weight of fuel, it is difficult to expect an effect as an additive for preventing fouling, slagging, and corrosion, and if it exceeds 5 parts by weight, economic efficiency may be reduced.

In addition, the additive composition for preventing fouling, slagging and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention may further include 0.1 to 5 parts by weight of coal ash, a by-product of a thermal power plant. That is, the coal ash may include 0.1 to 5 parts by weight based on 100 parts by weight of fuel input to a biomass mixture of a thermal power plant or a dedicated boiler.

The coal ash added to the fuel may include a function of providing the content of alumina and SiO ₂ necessary for chemical bonding, and specifically, the content of alumina can be adjusted to about 25%. However, the content is exemplary and is not necessarily limited.

Here, if the coal ash is less than 0.1 parts by weight, it is difficult to expect a role as an additive to prevent fouling and slagging, and when it exceeds 5 parts by weight, the alumina content of the additive composition decreases to prevent fouling, slagging and corrosion. Can be reduced.

In addition, the additive composition for preventing fouling, slagging, and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention is Al ₂ O _{3 in} which aluminum alumina is extracted from bauxite by Bayer method in aluminum smelting. It may further include 0.1 to 10 parts by weight of silica.

When the silica containing Al ₂ O ₃ is added to a biomass boiler, Al ₂ O ₃ and SiO ₂ may increase the melting point of inorganic substances, thereby preventing slagging and fouling in the combustion furnace. You can.

At this time, silica containing Al ₂ O ₃ is less than 0.1 parts by weight based on 100 parts by weight of fuel, it is difficult to expect a role as an additive to prevent fouling, slagging, etc. Economics may be reduced due to an increase in waste treatment costs due to unreacted reactions that do not react with alkali metals.

Hereinafter, the principle of the additive composition for preventing fouling, slagging and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention will be described in detail.

Biomass fuels generally contain alkali components such as K and Na, and when K and Na are formed in the form of K ₂ O and Na ₂ O, respectively, they generate low melting temperatures (below 800 ° C). Accordingly, when the temperature of the combustion chamber is maintained at 800 ° C or higher during the combustion process in the circulating fluidized bed boiler, the minerals in the fuel are discharged along the gas flow in a molten state, and then collide with the tube of the boiler to rapidly cool, agglomerate and adhere to and deposit on the tube surface. Occurs. The slagging and fouling phenomena generated in this way rapidly decrease the thermal efficiency in the boiler.

In order to solve this, in the present invention, the alumina (Al ₂ O ₃ ) additive composition may be introduced into a combustion furnace to increase the melting temperature of inorganic substances contained in the biomass, and the reaction formula is as follows.

(1) Al ₂ O ₃ · 6SiO ₂ + 2H ₂ O + 2K (OH)-> Al ₂ O ₃ · 6SiO ₂ · K ₂ O + 3H ₂ O

    (Rising the melting temperature of ash to about 1000 ℃)

(2) Al ₂ O ₃ · 2SiO ₂ + 2H ₂ O + 2Na (OH)-> Al ₂ O ₃ · 2SiO ₂ · Na ₂ O + 3H ₂ O

    (The melting temperature of ash is raised to about 1200 ℃)

After the alumina additive composition is added according to the above reaction formula, the melting temperature of the inorganic material in the biomass fuel exceeds the combustion temperature of the boiler, and an effect of chemically suppressing the slagging and fouling phenomenon caused by the molten inorganic material can be expected. .

Coal ash, which may be further included in the additive composition of the present invention, is a material that has already undergone a combustion process in a thermal power plant boiler, and does not burn when the additive composition is burned and remains as a solid component and circulates with ash. At this time, the circulating coal ash exerts an effect of physically removing the existing clinker from the furnace wall, and since it does not petrify when attached to the inner wall of the boiler, the effect of peeling the clinker from the inner wall can also be expected.

In addition, corrosion of the metal surface in the boiler is mainly formed at the contact point of the metal surface in the boiler in contact with the sediment where slagging and fouling are formed, so suppressing slagging and fouling creates an environment in which such corrosion can be achieved. It can bring about the suppressive effect.

Meanwhile, the additive composition for preventing fouling, slagging, and corrosion of a biomass mixture or a dedicated boiler using alumina according to an embodiment of the present invention may be composed of aluminum by-products having the same effect as alumina.

Here, the aluminum by-product is a by-product containing aluminum oxide (Al ₂ O ₃ ), 0.1 to 5 parts by weight of aluminum by-product may be added to 100 parts by weight of fuel to be fed into the biomass mixture or a dedicated boiler, wherein aluminum oxide The content of may be 10 to 90%.

This is because, for the same reason as the above-mentioned alumina, when the aluminum oxide content is less than 10%, it is difficult to expect an effect as an additive for fouling, slagging and corrosion prevention, and when it exceeds 90%, economic efficiency as an industrial byproduct can be reduced. to be.

In addition, the alumina and aluminum oxide by-products may have a particle size of 10 to 1500 μm, respectively. This, if the particle size of the aluminum by-product is less than 10μm, it is not possible to ensure a sufficient reaction time in the combustion furnace due to the floating phenomenon can be transferred to the rear end of the boiler cyclone, if the particle size exceeds 1500μm, fouling due to insufficient circulation, This is because the effect of slagging and corrosion prevention can be reduced.

Hereinafter, examples of the additive composition for preventing fouling, slagging and corrosion of a biomass mixture or a dedicated boiler using alumina according to the present invention will be described in more detail with reference to FIGS. The present invention is not limited by these.

[Experimental Example 1]

In order to investigate the relationship between alumina (aluminum oxide, Al ₂ O ₃ ) and potassium (K), an average of 919 tons of bituminous coal and 2,144 tons of wood pallet fuel were used in a circulating fluidized bed thermal power plant boiler, and 4 tons of alumina (fuel 100 0.131 parts by weight per part) and 5 tons of coal ash from thermal power plant (0.163 parts by weight per 100 parts by weight of fuel) were added and operated for an average of 22 hours per day for 9 days.

The suppression effect of slagging and fouling in the boiler is the higher the alkali content such as K and Na in the fly ash and bottom ash discharged outside the boiler, the alkali deposited and attached in the form of slagging and fouling in the boiler It can be confirmed that the components are low, which can be interpreted as slagging and fouling suppressed.

The graphs of potassium content in fly ash and bottom ash in Experimental Example 1 are summarized in FIG. 1, and the photographs before and after the experiment for a total of 9 days during the experimental period of Experimental Example 1 are shown in FIGS. 2 and 3, respectively.

[Experimental Example 2]

In order to examine the proper amount of alumina for fuel, the average of 900 tons of bituminous coal and 2,100 tons of wood pellets (a total of 3000 tons of fuel) and alumina were averaged in the 5th stage in a circulating fluidized bed thermal power plant boiler in Examples 1 to 4 below. And Comparative Example 1, the effect of preventing fouling, slagging, and corrosion was measured.

Measurement was conducted under the same conditions as Examples 1 to 4 and Comparative Example 1, and the boiler was operated for an average of 22 hours and 4 weeks a day, and the inside of the boiler was visually observed to very low the incidence of fouling, slagging, and corrosion. , Low, Normal, High, and Very High, and the results are shown in Table 1 below.

[Example 1]

1.5 tons of alumina was added to 3000 tons of fuel. (0.05 parts by weight of alumina relative to 100 parts by weight of fuel)

[Example 2]

3 tons of alumina were added to 3000 tons of fuel. (0.1 part by weight of alumina relative to 100 parts by weight of fuel)

[Example 3]

150 tons of alumina was added to 3000 tons of fuel. (5 parts by weight of alumina relative to 100 parts by weight of fuel)

[Example 4]

165 tons of alumina was added to 3000 tons of fuel. (5.5 parts by weight of alumina relative to 100 parts by weight of fuel)

[Comparative Example 1]

No alumina for 3000 tons of fuel

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Fouling Very high height lowness lowness Very high Slagging Very high usually Very low Very low Very high corrosion height usually lowness lowness Very high

Looking at Table 1, it was confirmed that the improvement in fouling, slagging and corrosion is not very excellent, but has an effect, compared to Comparative Example 1 in the case of Example 2, compared to Comparative Example 1 in Example 3 It can be confirmed that a remarkable effect is generated.

In addition, in Example 1, the improvement effect is minimal compared to Comparative Example 1, and in Example 4, it can be confirmed that there is no difference in effect compared to Example 3.

Accordingly, it can be seen that the effects of fouling, slagging, and corrosion can be seen to be introduced within the adjacent range between Example 2 and Example 3 (alumina is 0.1 to 5 parts by weight per 100 parts by weight of fuel). Can be confirmed.

The embodiments of the present invention have been described with reference to the accompanying drawings, but a person skilled in the art to which the present invention pertains may implement in other specific forms without changing the technical spirit or essential features of the present invention. You will understand. Therefore, the above-described embodiment is illustrative in all respects and is not limiting.

Claims (2)

It contains 0.1 to 5 parts by weight of alumina (Al ₂ O ₃ ) with respect to 100 parts by weight of fuel injected into the biomass mixture or a dedicated boiler,
Biomass mixed with alumina or an additive for preventing fouling, slagging and corrosion of a dedicated boiler using alumina, further comprising 0.1 to 5 parts by weight of coal ash, a by-product of a thermal power plant for providing silicon dioxide (SiO ₂ ) and controlling the content of alumina Composition.
According to claim 1,
In aluminum smelting, biomass mixing or dedicated boiler using alumina further comprising 0.1 to 10 parts by weight of silica containing Al ₂ O ₃ , which is a residue obtained by collecting alumina from bauxite by Bayer method, based on 100 parts by weight of fuel Additive composition for preventing fouling, slagging and corrosion.

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