Method for increasing melting temperature of biomass ash

Abstract

The invention relates to the technical field of clean utilization of solid waste resources, in particular to a method for increasing the melting temperature of biomass ash. The method comprises the following steps: mixing sludge and a biomass raw material to obtain a mixture; burning the mixture to obtain a mixed ash sample; wherein the mass ratio of the sludge in the mixture is 20%-80%. According to the method, co-gasification of the sludge and the biomass is utilized, the melting temperature interval of the mixed ash is adjusted by controlling the proportion of the sludge and the biomass, and the melting temperature of the biomass ash is increased. According to the method, additional additives are not needed, and the problems of gas path blockage, equipment damage and the like caused by easy sintering of ash during independent combustion of biomass are solved; meanwhile, by adding sludge with high ash content, an ash layer with a certain thickness can be formed at the bottom of the gasification furnace, direct contact between a high-temperature area of an oxide layer and a material at the bottom of a furnace body is blocked, and equipment damage caused by local overheating is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of clean utilization of solid waste resources, and particularly to a method for increasing the ash melting temperature of biomass. Background Art

[0002] With the excessive consumption of fossil energy and the promotion of the global carbon neutrality goal, environmental governance and renewable energy development have become the core issues of sustainable development. Against this background, biomass gasification technology, which combines resource utilization and carbon reduction potential, has attracted much attention. However, the slagging and equipment corrosion problems caused by the ash melting have increasingly become the core bottleneck restricting the long-term operation of the process. Biomass ash is rich in alkali metal oxides such as calcium, magnesium, potassium, sodium and chlorine elements. In the high-temperature reducing atmosphere of the gasifier, it is easy to form eutectic phases of low-melting-point silicates and chlorides, resulting in generally low ash melting temperatures. The molten ash adheres to the furnace wall or gas filtration device, not only reducing the heat transfer efficiency and blocking the gas flow channel, but also causing erosion of refractory materials and greatly increasing the equipment maintenance cost.

[0003] To alleviate the above problems, the prior art mostly uses the method of adding external chemical reagents such as kaolin or limestone to increase the ash melting temperature. However, additives such as kaolin need to be added at more than 10% of the ash mass to significantly increase the ash melting temperature, which not only increases the raw material pretreatment cost, but also may interfere with the gasification reaction path and reduce the content of effective components in the syngas. More critically, such methods all rely on the input of external substances and fail to fundamentally utilize the component characteristics of biomass itself to achieve the directional regulation of ash melting behavior. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this purpose, the present invention provides a method for increasing the ash melting temperature of biomass. This method uses the silicate in sludge ash to react with the alkali metal compounds in biomass ash to form high-melting-point minerals, which increases the melting temperature of the biomass mixed ash, broadens the melting range of the ash, and alleviates problems such as gas path blockage and equipment damage caused by biomass ash melting and slagging.

[0005] For this purpose, the present invention provides a method for increasing the ash melting temperature of biomass, which comprises the following steps:

[0006] Mix sludge and biomass raw materials to obtain a mixture;

[0007] Subject the mixture to a burning treatment to obtain a mixed ash sample;

[0008] Wherein, the mass ratio of sludge in the mixture is 20%-80%.

[0009] In view of the deficiencies of the prior art, the present invention provides a method for improving the ash fusion temperature of biomass by co-gasifying sludge and biomass. As a typical organic solid waste, the ash characteristics of sludge show significant complementarity with biomass. The ash of sludge is rich in acidic oxides such as silicon dioxide and aluminum oxide (with a proportion exceeding 50%), has a relatively high ash fusion temperature, and the ash yield can reach several to more than a dozen times that of biomass. If it is co-gasified with biomass, a large amount of silicate in the sludge ash can effectively capture the alkaline components in the biomass ash, generating high-melting-point minerals such as anorthite and mullite, thereby increasing the ash fusion temperature of the mixed ash. In addition, the high-ash characteristic of sludge can form a dense inert ash layer at the bottom of the gasifier, blocking the direct contact between the high-temperature area of the oxidation layer and the furnace body material, and avoiding equipment melting damage caused by local overheating. This synergistic effect not only avoids the cost and secondary pollution problems of the traditional additive method, but also provides an innovative path for sludge resource utilization, achieving the dual benefits of "treating waste with waste".

[0010] According to an embodiment of the present invention, the particle sizes of the sludge and biomass raw materials are independently 0 - 0.425 mm and not 0 mm.

[0011] According to an embodiment of the present invention, the dry basis ash content of the sludge is 50 wt% - 60 wt%.

[0012] According to an embodiment of the present invention, the chemical components of the dry basis ash of the sludge include silicon dioxide, iron oxide, aluminum oxide, calcium oxide, and phosphorus pentoxide.

[0013] According to an embodiment of the present invention, the total mass proportion of silicon dioxide, iron oxide, and aluminum oxide is higher than 75%, and the total mass proportion of calcium oxide and phosphorus pentoxide is 10% - 15%.

[0014] According to an embodiment of the present invention, the dry basis ash content of the biomass raw material is 0.8 wt% - 8.8 wt%.

[0015] According to an embodiment of the present invention, the chemical components of the dry basis ash of the biomass raw material include calcium oxide, magnesium oxide, potassium oxide, silicon dioxide, iron oxide, and aluminum oxide.

[0016] According to an embodiment of the present invention, in the chemical components of the dry basis ash of the biomass raw material, the mass proportion of calcium oxide is 10% - 55%, the total mass proportion of magnesium oxide and potassium oxide is 10% - 22%, and the total mass proportion of silicon dioxide, iron oxide, and aluminum oxide is 30% - 56%.

[0017] According to an embodiment of the present invention, the biomass raw material includes at least one of pine wood chips and corn straw.

[0018] According to an embodiment of the present invention, the temperature of the calcination treatment is 805 - 825 °C.

[0019] According to an embodiment of the present invention, the time of the calcination treatment is 3 - 4 h.

[0020] According to an embodiment of the present invention, the chemical components of the mixed ash sample include calcium oxide, magnesium oxide, potassium oxide, silicon dioxide, iron(III) oxide, and aluminum(III) oxide;

[0021] The total mass ratio of calcium oxide, magnesium oxide, and potassium oxide is 10% - 20%, the mass ratio of silicon dioxide is 30% - 45%, the mass ratio of iron(III) oxide is 20% - 30%, and the mass ratio of aluminum(III) oxide is 10% - 15%.

[0022] According to an embodiment of the present invention, the ash fusion temperature range of the biomass raw material is 1195 - 1328 °C, preferably 1222 - 1244 °C.

[0023] The beneficial effects of the present invention are as follows:

[0024] (1) The present invention provides a method for increasing the ash fusion temperature of biomass. By mixing biomass with dried sludge and controlling the mass ratio of biomass to sludge, the fusion temperature range of the mixed ash is adjusted to increase the ash fusion temperature of biomass. Without the need for additional additives, the problem that the ash fusion temperature is too low when biomass is burned alone and the ash is easily sintered into slag, resulting in equipment damage, is solved.

[0025] (2) The method proposed by the present invention is also applicable to a fixed bed, that is, biomass and sludge are co-gasified in a fixed bed after being mixed in a certain mass ratio. On the one hand, it can increase the ash fusion temperature of biomass and prevent the ash from sintering inside the equipment. On the other hand, by adding sludge with high ash content, a certain thickness of ash layer can be generated to block the direct contact between the high-temperature oxidation layer and the bottom of the gasifier, preventing equipment damage. Thus, biomass with lower ash content can also be gasified in a fixed bed, broadening the range of biomass types applicable to this technology.

[0026] The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and / or additional aspects and advantages of the present invention will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, where:

[0028] Figure 1Shows the test results of the deformation temperature (DT), softening temperature (ST), hemisphere temperature (HT), and flow temperature (FT) of the ash samples obtained in Examples 1-4 of the present invention and Comparative Example 1;

[0029] Figure 2 Shows the specific chemical compositions of the ash samples obtained in Examples 1-4 of the present invention and Comparative Example 1. Detailed Description of the Invention

[0030] The embodiments of the present invention will be described in detail below. The embodiments described below are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0031] It should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. Further, in the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0032] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0033] To make the present invention easier to understand, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by those of ordinary skill in the art to which the present invention pertains.

[0034] In this document, the term "comprising" or "including" is an open expression, that is, it includes the content specified by the present invention, but does not exclude other aspects of the content.

[0035] In this document, the terms "optionally", "optional" or "option" generally mean that the subsequent events or conditions may or may not occur, and this description includes the cases where such events or conditions occur and the cases where such events or conditions do not occur.

[0036] In the present invention, the "ash fusion temperature" has the meaning well-known in the art, that is, the temperature at which the ash in solid fuel deforms, softens and finally forms a liquid state during the heating process. Among them, biomass ash and sludge ash do not have a fixed melting point, but melt within a certain temperature range, which is called the melting characteristic of ash. The melting characteristic includes the deformation temperature (DT), softening temperature (ST), hemisphere temperature (HT) and flow temperature (FT).

[0037] In the present invention, the "dry basis ash" refers to the percentage of the remaining inorganic minerals (ash) in the total mass of the dry basis material after burning to remove all organic substances and volatile substances after the material is completely dried (moisture removed).

[0038] In the present invention, the "acidic oxide" has the meaning well-known in the art, that is, an oxide that can react with a base to form a salt and water, such as titanium dioxide, aluminum oxide, phosphorus pentoxide, silicon dioxide, etc.

[0039] In the present invention, the "basic oxide" has the meaning well-known in the art, that is, an oxide that can react with an acid to form a salt and water, such as calcium oxide, potassium oxide, magnesium oxide, sodium oxide, iron oxide, etc.

[0040] According to an embodiment of the present invention, the present invention provides a method for increasing the ash fusion temperature of biomass, comprising the following steps:

[0041] (1) Mix the sludge and biomass raw materials to obtain a mixture;

[0042] Wherein, the mass ratio of the sludge in the mixture is 20%-80%.

[0043] According to a specific embodiment of the present invention, the sludge is dehydrated sludge generated by a municipal sewage treatment plant, and its main sources include urban domestic sewage and part of industrial wastewater.

[0044] According to a specific embodiment of the present invention, the dry basis ash of the sludge is 50wt%-60wt%. As some specific examples, the dry basis ash of the sludge can be 50wt%, 52wt%, 54wt%, 56wt%, 58wt%, 60wt%.

[0045] According to a specific embodiment of the present invention, the chemical components of the dry - basis ash of the sludge include silicon dioxide, iron(III) oxide, aluminum(III) oxide, calcium oxide, and phosphorus pentoxide. Among them, the total mass proportion of silicon dioxide, iron(III) oxide, and aluminum(III) oxide is higher than 75%, and the total mass proportion of calcium oxide and phosphorus pentoxide is 10% - 15%. The sludge ash contains a large amount of acidic oxides (such as silicon dioxide, aluminum(III) oxide, etc.). Among them, acidic cations with higher ionic potential tend to combine with oxygen to form complex ionic structures or polymers, thereby increasing the melting temperature of the mixed ash.

[0046] According to a specific embodiment of the present invention, the dry - basis ash of the biomass raw material is 0.8wt% - 8.8wt%. As some specific examples, the dry - basis ash of the biomass raw material is 0.8wt%, 1.0wt%, 2.0wt%, 3.0wt%, 4.0wt%, 5.0wt%, 6.0wt%, 7.0wt%, 8.0wt%, 8.8wt%, etc.

[0047] According to a specific embodiment of the present invention, the chemical components of the dry - basis ash of the biomass raw material include calcium oxide, magnesium oxide, potassium oxide, silicon dioxide, iron(III) oxide, and aluminum(III) oxide. Among them, the mass proportion of calcium oxide is 10% - 55%, the total mass proportion of magnesium oxide and potassium oxide is 10% - 22%, and the total mass proportion of silicon dioxide, iron(III) oxide, and aluminum(III) oxide is 30% - 56%.

[0048] According to a specific embodiment of the present invention, the biomass raw material should meet the ash melting temperature range of 1195 - 1328°C, and the preferred ash melting temperature range is 1222 - 1244°C. As some specific examples, the biomass raw material can be pine wood chips, corn straw, etc.

[0049] According to a specific embodiment of the present invention, the particle sizes of the sludge and the biomass raw material are not particularly limited. As some specific examples, the particle sizes of the sludge and the biomass raw material can independently be 0 - 0.425mm and not 0mm. Specifically, after drying the sludge and the biomass raw material to a constant weight, they can be crushed to reach the target particle size.

[0050] (2) Conduct a burning treatment on the mixture to obtain a mixed ash sample.

[0051] According to a specific embodiment of the present invention, the temperature and time of the burning treatment are not particularly limited. As some specific examples, the temperature of the burning treatment can be 805 - 825°C, such as 805°C, 810°C, 815°C, 820°C, 825°C, etc.; the time of the burning treatment can be 3 - 4h, such as 3h, 3.5h, 4h, etc.

[0052] Specifically, the heating program during the calcination treatment is not particularly limited. It can be directly heated from room temperature to the target temperature, or it can be heated in stages, both of which have no impact on the calcination treatment. Specifically, it is preferably slowly heated from room temperature to 500 °C within 30 min, held at this temperature for 30 min, and then the temperature is raised to the target temperature within no less than 30 min for calcination.

[0053] According to a specific embodiment of the present invention, the chemical components of the mixed ash sample include calcium oxide, magnesium oxide, potassium oxide, silicon dioxide, iron(III) oxide, and aluminum(III) oxide;

[0054] The total mass ratio of calcium oxide, magnesium oxide, and potassium oxide is 10% - 20%, the mass ratio of silicon dioxide is 30% - 45%, the mass ratio of iron(III) oxide is 20% - 30%, and the mass ratio of aluminum(III) oxide is 10% - 15%.

[0055] According to a specific embodiment of the present invention, the flow temperature of the mixed ash sample can be increased to 1340 °C by the method provided by the present invention.

[0056] The solution of the present invention will be explained below in conjunction with embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the embodiments regarding specific techniques or conditions, they shall be carried out according to the techniques or conditions described in the literature in the art or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0057] Example 1

[0058] Using pine wood sawdust as the biomass raw material and sewage sludge from a sewage treatment plant as the sludge raw material, where the dry - basis ash content in the sludge is 54.45 wt%, the method for increasing the ash melting temperature of biomass provided by the present invention is carried out, including the following steps:

[0059] (1) After drying the pine wood sawdust (dry - basis ash content is 1.3 wt%) and the sludge raw material in an oven at 105 °C ± 0.5 °C to constant weight, they are crushed using a high - speed rotary cutter and screened through a 40 - mesh sieve. The undersize part of the sample is sealed and stored in a dry environment at room temperature;

[0060] (2) Mix the crushed sludge and biomass according to a mass ratio of 20:80 to obtain a mixed sample;

[0061] (3) Put the mixed sample into a muffle furnace, and increase the temperature from room temperature to 500 °C in a slow heating manner within no less than 30 min, and keep it at this temperature for 30 min. Increase the temperature to 815 ± 10 °C within no less than 30 min, and calcine it at this temperature for 3 h. After the calcination is completed, the sample is naturally cooled to room temperature, and then the ash is collected in a sealed container to obtain a mixed ash sample;

[0062] (4) Use a microcomputer ash melting point tester to measure the deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT) and flow temperature (FT) of the above ash sample; use an X-ray fluorescence spectrometer (XRF) to measure the chemical components in the ash sample.

[0063] Example 2

[0064] Using pine wood sawdust as the biomass raw material and sewage sludge from a sewage treatment plant as the sludge raw material, where the dry basis ash content in the sludge is 54.45 wt%, carry out according to the method for increasing the ash melting temperature of biomass provided by the present invention, including the following steps:

[0065] (1) After drying the pine wood sawdust (dry basis ash content is 1.3 wt%) and the sludge raw material in an oven at 105 °C ± 0.5 °C to constant weight, use a high-speed rotary cutter to crush them, and screen them through a 40-mesh sieve. The sample of the undersize part is sealed and stored in a dry environment at room temperature;

[0066] (2) Mix the above-mentioned crushed sludge and biomass in a mass ratio of 40:60 to obtain a mixed sample;

[0067] (3) Put the mixed sample into a muffle furnace, and increase the temperature from room temperature to 500 °C in a slow heating manner within no less than 30 min, and keep it at this temperature for 30 min. Increase the temperature to 815 ± 10 °C within no less than 30 min, and calcine it at this temperature for 3 h. After the calcination is completed, the sample is naturally cooled to room temperature, and then the ash is collected in a sealed container to obtain a mixed ash sample;

[0068] (4) Use a microcomputer ash melting point tester to measure the deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT) and flow temperature (FT) of the above ash sample; use an X-ray fluorescence spectrometer (XRF) to measure the chemical components in the ash sample.

[0069] Example 3

[0070] Using pine wood sawdust as the biomass raw material and sewage sludge from a sewage treatment plant as the sludge raw material, where the dry basis ash content in the sludge is 54.45 wt%, carry out according to the method for increasing the ash melting temperature of biomass of the present invention, including the following steps:

[0071] (1) After drying the pine wood sawdust (dry basis ash content is 1.3 wt%) and the sludge raw material in an oven at 105°C ± 0.5°C to constant weight, they are crushed using a high-speed rotary cutter and screened through a 40-mesh sieve. The undersize part of the sample is stored sealed at room temperature in a dry environment;

[0072] (2) Mix the above-mentioned crushed sludge and biomass in a mass ratio of 60:40 to obtain a mixed sample;

[0073] (3) Put the mixed sample into a muffle furnace. The temperature is slowly increased from room temperature to 500°C in no less than 30 minutes and kept constant at this temperature for 30 minutes. Subsequently, the temperature is increased to 815 ± 10°C in no less than 30 minutes and calcined at this temperature for 3 hours. After calcination, the sample is naturally cooled to room temperature, and then the ash is collected in a sealed container to obtain a mixed ash sample;

[0074] (4) Use a microcomputer ash melting point measuring instrument to measure the deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and flow temperature (FT) of the above ash sample; use an X-ray fluorescence spectrometer (XRF) to measure the chemical components in the ash sample.

[0075] Example 4

[0076] Using pine wood sawdust as the biomass raw material and sewage sludge from a sewage treatment plant as the sludge raw material, where the dry basis ash content in the sludge is 54.45 wt%, and following the method for increasing the ash melting temperature of biomass of the present invention, it includes the following steps:

[0077] (1) After drying the pine wood sawdust (dry basis ash content is 1.3 wt%) and the sludge raw material in an oven at 105°C ± 0.5°C to constant weight, they are crushed using a high-speed rotary cutter and screened through a 40-mesh sieve. The undersize part of the sample is stored sealed at room temperature in a dry environment;

[0078] (2) Mix the above-mentioned crushed sludge and biomass in a mass ratio of 80:20 to obtain a mixed sample;

[0079] (3) Put the mixed sample into a muffle furnace. The temperature is slowly increased from room temperature to 500°C in no less than 30 minutes and kept constant at this temperature for 30 minutes. Subsequently, the temperature is increased to 815 ± 10°C in no less than 30 minutes and calcined at this temperature for 3 hours. After calcination, the sample is naturally cooled to room temperature, and then the ash is collected in a sealed container to obtain a mixed ash sample;

[0080] (4) Use a microcomputer ash fusion temperature tester to measure the deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and flow temperature (FT) of the above ash samples; use an X-ray fluorescence spectrometer (XRF) to measure the chemical components in the ash samples.

[0081] Example 5

[0082] Using corn straw as the biomass raw material and sewage sludge from a sewage treatment plant as the sludge raw material, where the dry basis ash content in the sludge is 54.45 wt%, and following the method for increasing the ash fusion temperature of biomass of the present invention, which includes the following steps:

[0083] (1) After drying the corn straw (dry basis ash content is 8.74 wt%) and the sludge raw material in an oven at 105°C ± 0.5°C to constant weight, use a high-speed rotary cutter to crush them and sieve them through a 40-mesh sieve. The samples passing through the sieve are stored in a sealed container at room temperature in a dry environment;

[0084] (2) Mix the crushed sludge and biomass above according to a mass ratio of 20:80 to obtain a mixed sample;

[0085] (3) Put the mixed sample into a muffle furnace, and slowly increase the temperature from room temperature to 500°C in no less than 30 min, and keep it at this temperature for 30 min. Subsequently, increase the temperature to 815 ± 10°C in no less than 30 min and calcine it at this temperature for 3 h. After the calcination is completed, let the sample cool naturally to room temperature, and then collect the ash in a sealed container to obtain a mixed ash sample;

[0086] (4) Use a microcomputer ash fusion temperature tester to measure the deformation temperature (DT), softening temperature (ST), hemispherical temperature (HT), and flow temperature (FT) of the above ash sample.

[0087] Comparative Example 1

[0088] Directly carry out gasification treatment using pine wood sawdust as the biomass raw material, including the following steps:

[0089] (1) After drying the pine wood sawdust (dry basis ash content is 1.3 wt%) in an oven at 105°C ± 0.5°C to constant weight, use a high-speed rotary cutter to crush it and sieve it through a 40-mesh sieve. The samples passing through the sieve are stored in a sealed container at room temperature in a dry environment;

[0090] (2) Put the above-mentioned crushed biomass sample into a muffle furnace. Slowly increase the temperature from room temperature to 500 °C within no less than 30 minutes, and keep it at this temperature for 30 minutes. Then increase the temperature to 815 ± 10 °C within no less than 30 minutes and calcine at this temperature for 3 hours. After calcination, let the sample cool naturally to room temperature, and then collect the ash in a sealed container to obtain an ash sample;

[0091] (4) Use a microcomputer ash melting point analyzer to measure the deformation temperature (DT), softening temperature (ST), hemisphere temperature (HT), and flow temperature (FT) of the above-mentioned ash sample; use an X-ray fluorescence spectrometer (XRF) to measure the chemical components in the ash sample.

[0092] Comparative Example 2

[0093] Use corn straw as the biomass raw material for gasification treatment directly, including the following steps:

[0094] (1) After drying the corn straw (dry basis ash content is 8.74 wt%) to a constant weight in an oven at 105 °C ± 0.5 °C, use a high-speed rotary cutter to crush it, and screen it through a 40-mesh sieve. The sample passing through the sieve is stored in a sealed container at room temperature in a dry environment;

[0095] (2) Put the above-mentioned crushed biomass sample into a muffle furnace. Slowly increase the temperature from room temperature to 500 °C within no less than 30 minutes, and keep it at this temperature for 30 minutes. Then increase the temperature to 815 ± 10 °C within no less than 30 minutes and calcine at this temperature for 3 hours. After calcination, let the sample cool naturally to room temperature, and then collect the ash in a sealed container to obtain an ash sample;

[0096] (4) Use a microcomputer ash melting point analyzer to measure the deformation temperature (DT), softening temperature (ST), hemisphere temperature (HT), and flow temperature (FT) of the above-mentioned ash sample.

[0097] Test Example

[0098] (1) Measure the deformation temperature (DT), softening temperature (ST), hemisphere temperature (HT), and flow temperature (FT) of the ash samples obtained in each example and comparative example. The results are shown in Figure 1 (corresponding to Examples 1-4 and Comparative Example 1) and Table 1 (corresponding to Example 5 and Comparative Example 2). Figure 1It can be seen that the melting temperatures of the mixed ash of pine wood sawdust and sludge under different ratios are significantly different. Moreover, as the sludge content increases, the ST, HT, and FT of the mixed ash gradually increase, and the melting temperature range of the ash (the difference between FT and DT) continues to increase. This indicates that the addition of sludge delays the melting rate of the ash, enabling it to adapt to a wider gasification temperature range and alleviating the problem of ash sintering into slag. As can be seen from Table 1, the addition of sludge can also increase the melting temperature of corn straw ash (mainly reflected in DT, ST, and HT). Among them, ST is a relatively important index in the ash melting characteristics. When the reaction temperature reaches its ST, most of the minerals in the ash begin to be vitrified, and these substances will exist in a vitreous state. Therefore, ST largely determines the ease of ash slagging. The addition of sludge can increase the ST of corn straw ash, which can alleviate its slagging problem to a certain extent. Although the FT of the mixed ash decreases slightly, it is still higher than the ST of corn straw ash. In actual operation, to prevent ash from slagging in the furnace, the reaction temperature is usually 100 - 200 °C lower than the ST of the ash sample. Therefore, the addition of sludge can still play a role in alleviating the slagging of corn straw ash.

[0099] Table 1

[0100]

[0101] (2) The chemical compositions of the ash samples obtained from Examples 1 - 4 and Comparative Example 1 were measured, and the results are shown in Figure 2 . From Figure 2 it can be seen that the addition of sludge significantly reduces the contents of basic oxides such as calcium oxide and magnesium oxide in the mixed ash and increases the contents of acidic oxides such as silicon dioxide and aluminum oxide. Since acidic cations have a higher ionic potential and tend to combine with oxygen to form complex ionic structures or polymers, the melting temperature of the ash is thus increased; on the contrary, due to their lower ionic potential, basic cations act as oxygen donors in chemical reactions, which helps to inhibit the formation of polymers, reduce the viscosity of the melt, and ultimately lower the melting temperature of the ash. In summary, the addition of sludge adjusts the contents of acidic oxides and basic oxides in the mixed ash, thereby increasing the melting temperature of biomass ash.

[0102] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0103] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for increasing the ash fusion temperature of biomass, characterized in that, It includes the following steps: Mix sludge and biomass raw materials to obtain a mixture; Subject the mixture to calcination treatment to obtain a mixed ash sample; Wherein, the mass proportion of sludge in the mixture is 20%-80%.

2. The method according to claim 1, wherein The particle sizes of the sludge and the biomass raw materials are independently 0-0.425 mm and not 0 mm.

3. The method according to claim 1, characterized in that, The dry basis ash content of the sludge is 50 wt%-60 wt%.

4. The method according to claim 3, wherein The chemical components of the dry basis ash content of the sludge include silicon dioxide, iron(III) oxide, aluminum(III) oxide, calcium oxide, and phosphorus pentoxide.

5. The method according to claim 4, wherein The total mass proportion of silicon dioxide, iron(III) oxide, and aluminum(III) oxide is higher than 75%, and the total mass proportion of calcium oxide and phosphorus pentoxide is 10%-15%.

6. The method according to claim 1, characterized in that, The dry basis ash content of the biomass raw material is 0.8 wt%-8.8 wt%.

7. The method according to claim 6, characterized in that, The chemical components of the dry basis ash content of the biomass raw material include calcium oxide, magnesium oxide, potassium oxide, silicon dioxide, iron(III) oxide, and aluminum(III) oxide; Optionally, in the chemical components of the dry basis ash content of the biomass raw material, the mass proportion of calcium oxide is 10%-55%, the total mass proportion of magnesium oxide and potassium oxide is 10%-22%, and the total mass proportion of silicon dioxide, iron(III) oxide, and aluminum(III) oxide is 30%-56%; Optionally, the biomass raw material includes at least one of pine wood sawdust and corn straw.

8. The method according to claim 1, wherein The temperature of the calcination treatment is 805-825 °C; Optionally, the time of the calcination treatment is 3-4 h.

9. The method according to claim 1, wherein The chemical components of the mixed ash sample include calcium oxide, magnesium oxide, potassium oxide, silicon dioxide, iron(III) oxide, and aluminum(III) oxide; The total mass proportion of calcium oxide, magnesium oxide, and potassium oxide is 10%-20%, the mass proportion of silicon dioxide is 30%-45%, the mass proportion of iron(III) oxide is 20%-30%, and the mass proportion of aluminum(III) oxide is 10%-15%.

10. The method according to claim 1, wherein The ash fusion temperature range of the biomass raw material is 1195-1328 °C; Optionally, the ash fusion temperature range of the biomass raw material is 1222-1244 °C.

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