A plastic material specially used for CFB target area and its preparation process

Abstract

The present invention provides a special plastic material for CFB target area, including aggregate, fine powder, reinforcing agent, composite binder, composite mineralizer, composite plasticizer, moisturizer, etc. The aggregate is high-aluminum electric porcelain recycled material and brown corundum; the fine powder is fused corundum, silicon carbide, and fused quartz. The above raw materials are vigorously mixed and ground for 10 to 25 minutes until uniform, squeezed into a mud ball, sealed and packaged, and stored for use. The raw materials of the present invention are relatively cheap, the product has high strength, good wear resistance, low thermal conductivity, avoids target area red kiln, and has an ultra-long service life (≥8 years) when used in the target area of ​​the CFB boiler cyclone separator, with high cost performance and high customer acceptance.

Description

Technical Field

[0001] The invention relates to a special plastic material for CFB target area and a preparation process thereof, and belongs to the field of refractory materials of inorganic non-metallic material discipline. Background Art

[0002] CFB boiler combustion technology is recognized both domestically and internationally as a clean combustion technology, offering unique advantages such as low pollutant emissions, high combustion efficiency, a large load regulation ratio, and comprehensive ash and slag utilization. Most CFB plastics are based on alumina. Chinese patents CN107556008A, "Wear-Resistant and Refractory Plastic for Circulating Fluidized Bed Boilers," CN109422529A, "A High-Strength High-Aluminum Refractory Plastic for CFB Boilers," and CN107954733A, "In-Situ Aluminum Borate Whiskers Reinforced High-Strength and Wear-Resistant Plastic for CFB Boilers," disclose that the main components are bauxite or corundum with varying alumina contents, and phosphoric acid or phosphates as the binder. Phosphoric acid or phosphates react with iron impurities in the bauxite, resulting in a very short shelf life. The lower the grade of the bauxite in the plastic, the higher the impurity content and the shorter the shelf life. Furthermore, the need for on-site secondary mixing increases costs, and the varying proficiency of construction personnel can affect the mixing of the plastic, resulting in quality fluctuations. Third, the process requires the introduction of a large amount of phosphate binder, which is highly polluting. Many regions have now banned the use of phosphate-bound plastics. At the same time, the above patents all use the form of A and B materials, that is, a mixture of alumina-based aggregate and powder, adding an appropriate amount of phosphate binder, stirring the material to remove iron, and then bagging to make wet material A. The dry powder of admixtures such as early strength agents and plasticizers is then bagged to make dry powder B. The A and B materials are then delivered to the construction site, poured into a mixer for secondary stirring, and phosphate binder is added to mix evenly to form a ramming construction monolithic refractory material. Due to the large number of production steps, adding too much phosphate binder in the first step of material removal will affect the shelf life of the wet material, and adding too little phosphate binder will affect the iron removal effect, making it difficult to have a stable quality standard for plastics.

[0003] Chinese patent CN 116283245 A discloses an environmentally friendly plastic material for CFB furnaces and its preparation process, which avoids phosphate pollution and overcomes the difficulty in controlling the quality of secondary mixing on-site. However, the CFB boiler target area is the primary area where high-dust airflow, rotating at high speed within the separator, is impacted by centrifugal forces and is also the first area where particles collide with the separator wall. Consequently, the separator target area is subject to severe erosion and wear, and the refractory material is easily worn and detached, causing separator failure. This is comparable to the 2-3 year lifespan of currently used high-aluminum or silicon carbide wear-resistant plastic materials, making it difficult to avoid work delays and downtime caused by frequent maintenance. Chinese patent CN 107556005 A discloses a high-strength, wear-resistant plastic material made of chromium corundum, mullite, and silicon nitride for the target area of ​​CFB boiler cyclone separators. It features high strength, excellent wear resistance, and a service life exceeding eight years. However, the nano-alumina sol binder, βSi3N4, and βSialon, are expensive, and the high price of the product has reduced customer acceptance. CN113636832A discloses an aluminum-zirconium silicon carbide brick for the target area of ​​a CFB boiler cyclone separator and its preparation method. The brick utilizes a sintering process typically used for brickmaking, but high-temperature sintering is energy-inefficient and costly, and also uses environmentally unfriendly raw materials such as phosphoric acid. CN116514533A discloses a corrosion-resistant and wear-resistant plastic specifically for the SNCR (Sncr) target area of ​​a CFB and its preparation method. The raw materials include phosphoric acid solution, chromium oxide, 3-chloropropionyl chloride, and modified glass flakes, resulting in potential environmental pollution during both production and use. Summary of the Invention

[0004] The plastic material for CFB target areas of the present invention includes aggregate, fine powder, reinforcing agent, composite binder, composite mineralizer, composite plasticizer, moisturizer, etc. The aggregate is recycled high-alumina electric porcelain and brown corundum; the fine powder is fused corundum, silicon carbide, and fused quartz. The various raw materials are composed of the following ingredients in parts by mass:

[0005]

[0006] The reinforcing agent is a mixture of any two of cerium oxide, strontium oxide and cubic boron nitride. The particle sizes of cerium oxide, strontium oxide and cubic boron nitride are 0.002-0.005 mm.

[0007] The composite binder is prepared by mixing metaphosphate and CA cement in a ratio of 1:1 to 1:3.

[0008] The composite mineralizer is prepared by compounding pseudo-boehmite and talc in a ratio of 1:1, and the particle sizes of the pseudo-boehmite and talc are 0.002-0.005 mm.

[0009] The composite plasticizer is a mixture of hydroxy polyethylene oxide block copolymer, styrene phenol formaldehyde resin polyoxyethylene ether phosphate salt, hexagonal boron nitride, and kaolin.

[0010] Furthermore, the weight ratio of hydroxyl polyethylene oxide block copolymer: styrene phenol formaldehyde resin polyoxyethylene ether phosphate salt: hexagonal boron nitride: kaolin is 1:1:0.5:5 to 1:1:0.5:10.

[0011] The moisturizing agent is a mixture of vaseline, sodium lactate and urea in a ratio of 1:1:1 or a mixture of white mineral oil, sodium lactate and urea in a ratio of 1:1:1.

[0012] Mix the above raw materials vigorously for 10 to 25 minutes until they are uniform, squeeze them into a mud ball, seal it and store it for later use.

[0013] The main raw materials of the present invention are high-aluminum electric porcelain recycled materials, brown corundum, silicon carbide, fused corundum, and fused quartz. They have high strength, are adaptable to the high wear-resistant working condition requirements of the target area, and have high price customer acceptance. The metaphosphate and CA cement composite binder used are hydrated and bonded at room temperature. After drying, an interlaced structure is formed and embedded between particles and fine powder, thereby improving the bonding strength of the plastic blank. Under the effect of the composite mineralizer promoting sintering, the sintering temperature can be reduced, and the sensitivity of the plastic to temperature is reduced. When the temperature is high, the plastic is sintered into a hard sintered body. In combination with micron-level reinforcing agents, micropores are filled to make the plastic more dense, with higher strength and better wear resistance. The target area-specific plastic of the present invention is relatively kept stable at room temperature, medium temperature, and high temperature strength, and can reach more than 80MPa. The wetting agent added has the problem of preventing the plastic wet material from drying and deteriorating due to scratches caused by the transportation and handling process, thereby extending the shelf life.

[0014] The invention discloses a construction and maintenance method for a special plastic material for a CFB target area. The sealed and packaged plastic material is transported to the site, opened and directly rammed for construction. After the construction is completed, the plastic material is naturally dried for 48 to 96 hours, baked at 120°C for 48 hours, and then slowly heated to the working temperature at a heating rate of ≤20°C / h before being put into service.

[0015] The advantages of the present invention are: (1) The plastic product of the present invention is a plastic wet mud mass made by prefabricating the raw materials in the factory, which has stable quality and can be transported to the construction site without stirring, making construction convenient. (2) The plastic product of the present invention uses a compound of metaphosphate and CA cement as a binder to replace phosphoric acid or phosphate, which is both environmentally friendly and can prevent construction tools from rusting. (3) The added moisturizer can prevent scratches during transportation from causing damage to the sealed packaging and causing the plastic wet material to dry out and deteriorate, and the shelf life can be extended by 2 to 3 times to 12 to 18 months. (4) The raw materials of the present invention are relatively cheap, the product has high strength, good wear resistance, low thermal conductivity, avoids target area red kiln, and has a very long service life (≥8 years) when used in the target area of ​​the CFB boiler cyclone separator, with high cost performance and high customer acceptance. DETAILED DESCRIPTION

[0016] Example 1

[0017] The plastic material specially used for CFB target area is composed of various raw materials in parts by mass:

[0018]

[0019] The reinforcing agent is a mixture of two or more of cerium oxide, strontium oxide and cubic boron nitride in any proportion. The particle size of cerium oxide, strontium oxide and cubic boron nitride is 0.002-0.005 mm.

[0020] The composite binder is prepared by mixing metaphosphate and CA cement in a ratio of 1:2.

[0021] The composite mineralizer is prepared by compounding pseudo-boehmite and talc in a ratio of 1:1, and the particle sizes of the pseudo-boehmite and talc are 0.002-0.005 mm.

[0022] The composite plasticizer is a mixture of hydroxy polyethylene oxide block copolymer, styrene phenol formaldehyde resin polyoxyethylene ether phosphate, kaolin and hexagonal boron nitride, and is prepared by compounding in a ratio of hydroxy polyethylene oxide block copolymer: styrene phenol formaldehyde resin polyoxyethylene ether phosphate: kaolin: hexagonal boron nitride of 1:1:8:0.5.

[0023] The moisturizing agent is a mixture of vaseline, sodium lactate and urea in a ratio of 1:1:1.

[0024] Mix the above raw materials vigorously for 25 minutes until uniform, squeeze into a mud ball, seal and package, and store for later use.

[0025] Table 1 lists the properties of Example 1 after ramming construction, natural drying for 96 hours, baking at 120°C for 48 hours, and then slowly heating to 1400°C for 3 hours at a heating rate of ≤20°C / h. The plastic was used in the 420t / h separator target area of ​​the Shanghai Moutun Energy Co., Ltd. power plant (changed to Jiangsu Moutun Thermal Power Co., Ltd. in 2020) for 8 years without damage or maintenance.

[0026] Example 2

[0027] The plastic material specially used for CFB target area is composed of various raw materials in parts by mass:

[0028]

[0029] The reinforcing agent is a mixture of two or more of cerium oxide, strontium oxide and cubic boron nitride in any proportion. The particle size of cerium oxide, strontium oxide and cubic boron nitride is 0.002-0.005 mm.

[0030] The composite binder is prepared by mixing metaphosphate and CA cement in a ratio of 1:2.

[0031] The composite mineralizer is prepared by compounding pseudo-boehmite and talc in a ratio of 1:1, and the particle sizes of the pseudo-boehmite and talc are 0.002-0.005 mm.

[0032] The composite plasticizer is a mixture of hydroxy polyethylene oxide block copolymer, styrene phenol formaldehyde resin polyoxyethylene ether phosphate, kaolin and hexagonal boron nitride, and is prepared by compounding in a ratio of hydroxy polyethylene oxide block copolymer: styrene phenol formaldehyde resin polyoxyethylene ether phosphate: kaolin: hexagonal boron nitride of 1:1:8:0.5.

[0033] The moisturizing agent is a mixture of vaseline, sodium lactate and urea in a ratio of 1:1:1.

[0034] Mix the above raw materials vigorously for 10 minutes until uniform, squeeze into a mud ball, seal and package, and store for later use.

[0035] Table 1 lists the properties of Example 2 after ramming, natural drying for 48 hours, baking at 120°C for 48 hours, and then slowly heating to 1400°C for 3 hours at a heating rate of ≤20°C / h. The plastic material was in good condition in the target area of ​​two 300MW Dongfang boiler units at the Huaheshuyuan Power Plant in Guangdong Province, which have been in operation for 10 years.

[0036] Example 3

[0037] The plastic material specially used for CFB target area is composed of various raw materials in parts by mass:

[0038]

[0039]

[0040] The reinforcing agent is a mixture of two or more of cerium oxide, strontium oxide and cubic boron nitride in any proportion. The particle size of cerium oxide, strontium oxide and cubic boron nitride is 0.002-0.005 mm.

[0041] The composite binder is prepared by mixing metaphosphate and CA cement in a ratio of 1:2.

[0042] The composite mineralizer is prepared by compounding pseudo-boehmite and talc in a ratio of 1:1, and the particle sizes of the pseudo-boehmite and talc are 0.002-0.005 mm.

[0043] The composite plasticizer is a mixture of hydroxy polyethylene oxide block copolymer, styrene phenol formaldehyde resin polyoxyethylene ether phosphate, kaolin and hexagonal boron nitride, and is prepared by compounding in a ratio of hydroxy polyethylene oxide block copolymer: styrene phenol formaldehyde resin polyoxyethylene ether phosphate: kaolin: hexagonal boron nitride of 1:1:8:0.5.

[0044] The moisturizing agent is a mixture of vaseline, sodium lactate and urea in a ratio of 1:1:1.

[0045] Mix the above raw materials vigorously for 20 minutes until uniform, squeeze into a mud ball, seal and package, and store for later use.

[0046] Table 1 lists the properties of Example 3 after ramming, natural drying for 72 hours, baking at 120°C for 48 hours, and then slowly heating to 1400°C for 3 hours at a heating rate of ≤20°C / h. This plastic was used in the 1025t / h CFB at the Huaheshuyuan Power Plant in Guangdong. After eight years of use, the target area lining thickness was over 95% of its original thickness.

[0047] Example 4

[0048] The plastic material for the CFB target area, with the exception of the composite plasticizer, has the same raw material composition as in Example 2, with the composite plasticizer composition and ratio of hydroxyl polyethylene oxide block copolymer: styrene phenol formaldehyde resin polyoxyethylene ether phosphate salt: kaolin: hexagonal boron nitride being 1:1:5:0.5. The construction method and performance testing methods for this example are the same as those for Examples 1-3.

[0049] Example 5

[0050] The plastic material for the CFB target area, with the exception of the composite plasticizer, has the same raw material composition as in Example 2, with the composite plasticizer composition and ratio of hydroxyl polyethylene oxide block copolymer: styrene phenol formaldehyde resin polyoxyethylene ether phosphate salt: kaolin: hexagonal boron nitride being 1:1:10:0.5. The construction method and performance testing methods for this example are the same as those for Examples 1-3.

[0051] Example 6

[0052] The CFB target area-specific plastic material, calculated by weight, has the same raw material composition as in Example 2, except for the composite binder. In this example, the composite binder is preferably a mixture of metaphosphate and CA cement in a ratio of 1:1. The construction method and performance testing methods of this example are the same as those of Examples 1-3.

[0053] Example 7

[0054] The CFB target area-specific plastic material, calculated by weight, has the same raw material composition as in Example 2, except for the composite binder. In this example, the composite binder is preferably a mixture of metaphosphate and CA cement in a ratio of 1:3. The construction method and performance testing methods of this example are the same as those of Examples 1-3.

[0055] Example 8

[0056] The plastic material specifically for the CFB target area, with the exception of the moisturizing agent, consists of the same raw materials as in Example 2, with the remaining ingredients being a mixture of white mineral oil, sodium lactate, and urea in a mass ratio of 1:1:1. The construction method and performance testing methods for this example are the same as those for Examples 1-3.

[0057] Table 1 Properties of the CFB target area special plastics prepared in Examples 1-3 after calcination at 1400°C for 3 hours

[0058]

Claims

1. A plastic material specially used for CFB target area, wherein the raw materials are composed of the following ingredients in parts by mass: The reinforcing agent is a mixture of any two of cerium oxide, strontium oxide and cubic boron nitride; The composite binder is prepared by compounding metaphosphate and CA cement; The composite mineralizer is prepared by compounding pseudo-boehmite and talc; The composite plasticizer is a mixture of hydroxy polyethylene oxide block copolymer, styrene phenol formaldehyde resin polyoxyethylene ether phosphate salt, hexagonal boron nitride and kaolin.

2. The CFB target area-specific plastic material according to claim 1, characterized in that: The particle sizes of the cerium oxide, strontium oxide and cubic boron nitride are 0.002-0.005 mm.

3. The CFB target area-specific plastic material according to claim 1, characterized in that: The composite binder is prepared by mixing metaphosphate and CA cement in a ratio of 1:1 to 1:

3.

4. The CFB target area-specific plastic material according to claim 1, characterized in that: The composite mineralizer is prepared by mixing pseudo-boehmite and talc in a ratio of 1:

1.

5. The CFB target area-specific plastic material according to claim 4, characterized in that: The particle size of the pseudo-boehmite and talc is 0.002-0.005 mm.

6. The CFB target area-specific plastic material according to claim 1, characterized in that: The weight ratio of hydroxy polyethylene oxide block copolymer: styrene phenol formaldehyde resin polyoxyethylene ether phosphate salt: hexagonal boron nitride: kaolin is 1:1:0.5:5 to 1:1:0.5:

10.

7. The CFB target area-specific plastic material according to claim 1, characterized in that: The moisturizing agent is a mixture of vaseline, sodium lactate and urea in a ratio of 1:1:

1.

8. The CFB target area-specific plastic material according to claim 1, characterized in that: The moisturizing agent is a mixture of white mineral oil, sodium lactate and urea in a ratio of 1:1:

1.

9. The method for preparing a plastic material for a CFB target area according to any one of claims 1 to 8, characterized in that: The raw materials according to any one of claims 1 to 8 are vigorously mixed and ground for 10 to 25 minutes until uniform, squeezed into a mud ball, sealed and packaged, and stored for later use.

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