Slag melting agent for high-sodium coal liquid deslagging gasifier

Abstract

The invention relates to a slag melting agent for a high-sodium coal liquid deslagging gasification furnace. The slag melting agent comprises 10-20 parts of a puffing bulking agent and 40-60 parts of an oxidizing slag melting agent. The method has the beneficial effects that the puffing bulking agent can be used for expanding and loosening the ash residues and effectively melting refractory acidic oxides, so that the refractory acidic oxides are converted into fluidization; the method comprises the following steps of: mixing ash slag with an oxidizing slag melting agent added in the raw materials, so that refractory silicon-aluminum compounds in the ash slag are subjected to chemical reaction to generate low-melting-point sodium-containing silicate and low-temperature eutectic, and the sodium-containing silicate and the low-temperature eutectic are fully melted at a lower temperature. The metering of the slag melting agent is adjusted according to the property of slag, and the slag melting agent is sprayed into a nozzle above a slag discharging opening of a liquid slag discharging gasification furnace using high-sodium coal, so that effective slag melting at about 900 DEG C can be realized, the requirement of liquid slag discharging is met, the problems of energy waste and cost increase caused by using a large amount of natural gas are avoided, and the slag melting agent is suitable for industrial production. And meanwhile, non-planned furnace shutdown caused by slag blockage can be avoided, the production cost is effectively reduced, and smooth slag discharge is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of gasifier additives, and particularly to a slagging agent for a high-sodium coal liquid slagging gasifier. Background Art

[0002] Xinjiang Uygur Autonomous Region has 2.19 trillion tons of coal reserves, ranking first in the country. To ensure the national energy strategic security, Xinjiang has listed coal, coal power and coal chemical industry as one of the top ten key development industrial clusters. The coal resources in the Zhundong area of Xinjiang have relatively high contents of alkali metals and alkaline earth metals and belong to typical high-alkali coal. However, due to the relatively high content of sodium element in high-alkali coal, slag plugging problems are very likely to occur during the gasification and slag discharging processes.

[0003] NaCl, NaOH and Na vapor released during the gasification of high-sodium coal will condense on the heated wall surface. As the gasification temperature rises, the released elements such as Na, Ca, Mg, Si, Cl, and S interact, nucleate and form various forms of viscous particles, such as Na-Al-Si-O, etc., and finally deposit on the wall surface of the heated surface through the action of thermophoretic diffusion and inertial collision. At the same time, metal minerals such as Ca, Fe, and Mg are enriched on the surface. As the residence time increases, these particles bond and agglomerate with each other and finally lead to slagging.

[0004] Alkali metal compounds may be in a gaseous or molten state at high temperatures, but are prone to sticking to the heated wall surface when cooled, forming growing ash deposits. In a liquid slagging gasifier burning high-sodium coal, the temperature at the slag discharging outlet is usually relatively low. Even when using high-alkali coal, when encountering the relatively low-temperature slag discharging port interface, problems such as slag plugging are very likely to occur, which has a significant impact on the safe and economic operation of the gasifier. In recent years, with the growth of energy demand, the usage amount of high-sodium coal has also been continuously increasing, and problems such as serious slagging have gradually emerged. Solving the problem of low-temperature slag discharging in a liquid slagging gasifier is of great significance.

[0005] Currently, mainly by spraying natural gas above the slag discharging port of the gasifier to increase the temperature of the slag discharging port and promote the transformation of the slag body into a liquid state. This method can play a certain role in promoting slag melting and slag discharging. However, due to the unclear characteristics such as the melting point of the slag body, it is only possible to continuously introduce natural gas to heat the slag discharging port to form a liquid slag discharging mode, resulting in a certain degree of waste of natural gas resources and an increase in gasification costs. Therefore, there is an urgent need to propose a solution to the problem of promoting slag discharging for a liquid slagging gasifier using high-sodium coal at present, but no relevant technologies have been applied. Summary of the Invention

[0006] In order to solve the defect of energy waste caused by using a large amount of natural gas to increase the temperature of the slag discharging port of a liquid slagging gasifier at present, the purpose of the present invention is to provide a slagging agent for a high-sodium coal liquid slagging gasifier.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A slag melting agent for a high-sodium coal liquid slagging gasifier, comprising 10-20 parts of an expanding and loosening agent and 40-60 parts of an oxidizing slag melting agent.

[0008] Further, the expanding and loosening agent includes sodium bicarbonate, sodium hydroxide, sodium borate, activated carbon, indolylacetic acid, calcium carbonate, and calcium hydroxide.

[0009] Further, the oxidizing slag melting agent includes potassium permanganate, potassium nitrate, sodium peroxide, and sodium carbonate.

[0010] The present invention also provides a preparation method for a slag melting agent for a high-sodium coal liquid slagging gasifier, comprising the following steps: Mix the sodium bicarbonate and sodium hydroxide according to a molar ratio of (4-7):(1-3) to obtain a solid material; put the solid material into a vacuum drying oven and dry it at 200 °C for 2-3 h; take out the dried solid material and grind it to less than 48 µm in a vacuum glove box.

[0011] Add the indolylacetic acid to absolute ethanol and stir well, add activated carbon particles to the indolylacetic acid solution to ensure that the activated carbon is completely immersed to obtain a solid-liquid mixture; fully oscillate and stir the solid-liquid mixture at 30-50 °C for 7-12 h; filter and collect the solid material of the oscillated and stirred solid-liquid mixture to obtain the loaded activated carbon; fully grind the loaded activated carbon to less than 48 µm.

[0012] Place the loaded activated carbon in a vacuum drying oven and dry it at 50-80 °C; add sodium borate, calcium carbonate, and calcium hydroxide to the dried loaded activated carbon according to a mass ratio of (5-7):(20-40):(7-15):(7-15), and fully grind the mixed material to less than 48 µm.

[0013] Fully mix the materials obtained in steps 1 and 3 according to a mass ratio of (5-10):(20-30) to obtain an expanding and loosening agent.

[0014] Mix the potassium permanganate, potassium nitrate, sodium peroxide, and sodium carbonate according to a mass ratio of (5-8):(5-7):(10-15):(20-30) and fully grind them to less than 48 µm to obtain an oxidizing slag melting agent.

[0015] Compared with the prior art, the beneficial effects of the present invention are: ①In the present invention, sodium bicarbonate and sodium hydroxide are added to the puffing and loosening agent. Both of them can react with the high-melting-point acidic oxides (such as SiO2, Al2O3, etc.) in the slag, reducing the overall melting point of the molten slag and facilitating the liquid slag discharge at a lower temperature. Activated carbon-supported indolylacetic acid is added to adsorb impurities and harmful components in the molten slag and stabilize the chemical properties of the molten slag. Indolylacetic acid contains functional groups such as carboxyl and indolyl. The carboxyl group can undergo a coordination chemical reaction with metal ions (such as Fe 3+ , Ca 2+ ) in the molten slag. The oxygen atom in the carboxyl group provides a lone pair of electrons to form a coordination bond with the metal ion, thereby fixing the metal ion on the surface of the activated carbon. In addition, indolylacetic acid can provide a suitable acidic environment for the reaction process between sodium bicarbonate and acidic oxides, form a transition state complex with the reactants, reduce the activation energy of the reaction, make the reaction easier to occur, and promote the expansion process of the slag, thus facilitating the discharge of the slag in a liquid form.

[0016] ②In the present invention, sodium borate, calcium carbonate and calcium hydroxide are added to promote the loosening of the slag. Sodium borate destroys the tight silicon-oxygen tetrahedron structure in the molten slag, breaks some chemical bonds, makes the molten slag structure loose, enhances its fluidity. Sodium borate molecules can also adsorb on the crystal nuclei surface of the molten slag crystallization, change the growth direction and speed of the crystals in the molten slag, making it difficult for crystallization to proceed smoothly. Calcium chloride and calcium hydroxide can not only react with the acidic oxides in the molten slag to generate silicate aluminates with lower melting points and more stable properties, but also adjust the pH value of the slag, making the pH value of the molten slag reach a range conducive to flow and reaction.

[0017] ③In the present invention, potassium permanganate, potassium nitrate, sodium peroxide and sodium carbonate are added as oxidation slag agents to promote the effect of the molten slag. At high temperatures, potassium permanganate and potassium nitrate decompose to generate potassium manganate, manganese dioxide and potassium nitrite respectively. These substances can react with acidic oxides to generate low-melting-point compounds. The formation of new compounds changes the distribution of ionic bonds and covalent bonds, thereby changing the slag structure and facilitating liquid slag discharge. Sodium peroxide reacts with sulfides in the slag to generate sodium sulfate, reducing the viscosity of the molten slag. In addition to reacting with acidic oxides to reduce the melting point, sodium carbonate can also release carbon dioxide gas, making the internal components of the molten slag more uniform, improving fluidity and facilitating liquid slag discharge. Detailed implementation mode

[0018] The various exemplary implementation modes of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention. It should be understood that the terms described in the present invention are only for describing specific implementation modes and are not used to limit the present invention.

[0019] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0020] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0021] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the description of the present invention, which are obvious to those skilled in the art. Other embodiments obtained from the description of the present invention are obvious to those skilled in the art. The description and examples of the present invention are merely exemplary.

[0022] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0023] In the examples of the present invention, the "parts" mentioned are all in parts by mass.

[0024] The following further describes the present invention in detail with reference to specific examples. Example

[0025] A slag flux for alleviating slagging in a high-sodium coal liquid slagging gasifier, comprising the following raw materials: 15 parts of an expanded and loosening agent and 60 parts of an oxidized slag flux.

[0026] A preparation method of a slag flux for a high-sodium coal liquid slagging gasifier, comprising the following steps: stirring and uniformly mixing the expanded and loosening agent and the oxidized slag flux, and then drying in vacuum at 100 °C for 120 min to obtain a slag flux for a high-sodium coal liquid slagging gasifier. Example

[0027] A slag flux for a high-sodium coal liquid slagging gasifier, comprising the following raw materials: 20 parts of an expanded and loosening agent and 55 parts of an oxidized slag flux.

[0028] The preparation method of a slag flux for a high-sodium coal liquid slagging gasifier is the same as that in Example 1. Example

[0029] A slagging agent for a high-sodium coal liquid slagging gasifier comprises the following raw materials: 17 parts of an expanded and loosening agent and 58 parts of an oxidized slagging agent.

[0030] The preparation method of a slagging agent for a high-sodium coal liquid slagging gasifier is the same as that of Example 1.

[0031] Comparative Example 1 A slagging agent for a high-sodium coal liquid slagging gasifier, which is different from Example 1 in that the high-temperature slag oxidant is 50 parts.

[0032] The remaining raw materials are the same as those in Example 1.

[0033] The preparation method of a slagging agent for a high-sodium coal liquid slagging gasifier is the same as that of Example 1.

[0034] Comparative Example 2 A slagging agent for a high-sodium coal liquid slagging gasifier, which is different from Example 2 in that the expanded and loosening agent is 13 parts.

[0035] The remaining raw materials are the same as those in Example 2.

[0036] The preparation method of a slagging agent for a high-sodium coal liquid slagging gasifier is the same as that of Example 1.

[0037] Performance test The slagging agents for a high-sodium coal liquid slagging gasifier prepared in the above Examples 1-3 and Comparative Examples 1-2 are sprayed at the slag discharge outlet of the gasifier for performance testing.

[0038] As mentioned above, the above are only the preferred specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered by the protection scope of the present invention.

Claims

1. A slag flux for a high-sodium coal liquid slagging gasifier comprises an expanding and loosening agent and an oxidizing slag flux.

2. The slagging agent for a high-sodium coal liquid slagging gasifier according to claim 1, wherein The mass parts of the raw materials are: 10-20 parts of the expanding and loosening agent and 40-60 parts of the oxidizing slag flux.

3. The slagging agent for a high-sodium coal liquid slagging gasifier according to claim 1, wherein The expanding and loosening agent comprises sodium bicarbonate, sodium hydroxide, sodium borate, indolylacetic acid, activated carbon, calcium carbonate and calcium hydroxide.

4. A slagging agent for a high-sodium coal liquid slagging gasifier according to claim 1, characterized in that The oxidizing slag flux comprises potassium permanganate, potassium nitrate, sodium peroxide and sodium carbonate.

5. A slagging agent for a high-sodium coal liquid slagging gasifier according to claim 1, characterized in that Adjust the dosage used according to the gasification raw materials and slag properties in the furnace.

6. A preparation method of a slag melting agent for a high-sodium coal liquid slagging gasifier, comprising the slag melting agent for a high-sodium coal liquid slagging gasifier according to any one of claims 1-5, characterized in that It includes the following steps: S1: Raw material selection, treatment and weighing: Select the raw materials of the expanding and loosening agent and the oxidizing slag flux in the required weight ratio, and carry out, grind and screen various raw materials, and then place them separately inside the storage tank; S2: Prepare the materials 1 required for the expanding and loosening agent: Mix sodium bicarbonate and sodium hydroxide according to the molar ratio of (4-7):(1-3) to obtain a solid material; Put the solid material into a vacuum drying oven and dry it at 200 °C for 2-3 h; After taking out the dried solid material, grind it to below 48 µm in a vacuum glove box; S3: Make the loaded activated carbon: Add indolylacetic acid to absolute ethanol and stir well, add activated carbon particles to the indolylacetic acid solution to ensure that the activated carbon is completely immersed to obtain a solid-liquid mixture; Oscillate and stir the solid-liquid mixture at 30-50 °C for 7-12 h; Filter and collect the solid material of the oscillated and stirred solid-liquid mixture to obtain the loaded activated carbon; Place the loaded activated carbon in a vacuum drying oven and dry it at 50-80 °C to obtain the loaded activated carbon; S4: Prepare the materials 2 required for the expanding and loosening agent: Add sodium borate, calcium carbonate and calcium hydroxide to the dried loaded activated carbon in a mass ratio of (5-7):(20-40):(7-15):(7-15), and grind the mixed materials to below 48 µm; S5: Make the expanding and loosening agent: Mix the materials obtained in steps S2 and S4 according to the mass ratio of (5-10):(20-30) to obtain the expanding and loosening agent; S6: Make the oxidizing slag flux: Mix the potassium permanganate, potassium nitrate, sodium peroxide and sodium carbonate according to the mass ratio of (5-8):(5-7):(10-15):(20-30) and grind them to below 48 µm to obtain the oxidizing slag flux.

7. The slagging agent for a high-sodium coal liquid slagging gasifier according to claim 6, wherein The output power of the oscillation device in S3 is 300-400 W.