Boiler castables are lining materials used in circulating fluidized bed boilers, including high-strength wear-resistant castables, wear-resistant plastics, and other refractory materials. Among them, the combustion characteristics of the boiler determine the quality of wear-resistant materials, and the quality of the furnace is one of the key factors related to the long-term, safe and reliable operation of the boiler. Therefore, the masonry materials must be strictly in accordance with the materials provided by the material manufacturer.
Instructions for use and reasonable operation.
1: Preparation before construction
(1) Main machines and tools. Compulsory mixer, trolley, rubber bucket, trowel, winch, φ25/φ35 portable vibrating rod, tamping machine, rubber hammer, weighing scale, etc.
(2) The inner surface of boiler wall panels is qualified for rust removal. The sandblasted wall panels should remove loose oxide scale and oil stains. All sand and debris must be cleaned to prevent impurities from being mixed into the castable.
(3) The location of anchoring nails meets the design requirements, and the welding is firm: the embedded metal parts (anchors) and the cast metal surface are evenly coated with a layer of asphalt paint with a thickness of 2mm before pouring, or there must be no omissions according to the design requirements.
Two: construction method
2.1 Use of high-strength and wear-resistant castables
(1) Mixing of high-strength wear-resistant castables.
a High-strength wear-resistant castables are generally packaged in woven bags: composed of a mixture and a binder, and the binder is packaged separately.
b After adding high-strength and wear-resistant castables (mixtures, binders) to the mixer, dry mix for 3min~5inm to make the mixtures and binders in the sachets open the package and then disperse and mix thoroughly (to keep the color consistent), and then add up to 5.5 at a time %~6.5% (PH=6.5~7.5) clean tap water, stir while adding water, the wet mixing time should not be less than 5min (the time should be fully guaranteed). Water must not be added at will, and must be weighed with a weighing instrument (special water adding measuring cup). Strictly controlling the amount of water added to the minimum is an important measure to ensure the material strength and excellent performance indicators.
C The high-strength wear-resistant castables that have been mixed each time must be used up within 30 minutes. If the castables are found to have agglomerated or lose their fluidity, they should be discarded. The castable that has been prepared cannot be mixed with water twice during the construction process.
(2) Forming construction of high-strength wear-resistant castables.
a After adding the mixed high-strength wear-resistant castable to the construction work surface at one time, turn on the vibrating rod and vibrate until the surface of the high-strength wear-resistant castable is prone to slurry and no large amount of air bubbles escape. The joints of the supporting formwork should be sealed with sealing tape to prevent slurry leakage. Once there is slurry leakage, the strength of the castable will be affected.
b. The operator of the vibrating rod inserted into the high-strength wear-resistant pouring material should be fixed in posts and personnel: the pouring should be symmetrical and uniformly continuous: vibrating should be applied to the portable vibrating rod for mechanical vibration and manual tamping. If necessary, the surface of the template should be properly vibrated , The vibrating rod moves at an interval of 200mm and each vibration time is about 30s. The method of "quick insertion" and "full pumping" is adopted to move slowly until the surface is flooded and no bubbles are generated. The vibration time should not be too long, no leakage or over vibration . When the vibration is completed, the rod should be pulled slowly, otherwise segregation will occur, which will affect the material, strength and performance.
C. It is best to pour to the specified thickness at one time during construction, and the vibration is completely dense. For thicker parts, the layered construction method should be adopted. When the upper layer of the castable, the vibrating rod should touch 1/3 of the lower layer of the casted material, so that the upper and lower layers of castable are tightly combined.
d During the construction process, the wooden block supporting the thickness of the castable is not allowed to be hoisted or left in the formwork being poured.
e The high-strength wear-resistant castable that has been transported to the working surface must be used up before its initial setting. High-strength wear-resistant castables that have been initially set should not be used.
(3) Maintenance and mold removal of high-strength wear-resistant castables.
a After the construction of the castable, the temperature is below 20℃, the demoulding time shall not be less than 96h, and the demoulding shall not be less than 48h above 20℃.
b After moist curing, the castable must be subjected to strict thermal curing and baking. It can be put into use only after the thermal curing and baking are qualified.
Three: high-strength wear-resistant plastic construction
(1) The composition and packaging of high-strength wear-resistant plastic.
a High-strength and wear-resistant plastics include high-bauxite (corundum, mullite, silicon carbide) clinker grade one ultra-fine powder compounding mixture. It is composed of aluminum phosphate binder, coagulant and admixture.
b High-strength wear-resistant plastic powders are packed in woven bags, and plastic binders are packed in plastic buckets. The coagulant for plastics has been packaged in small bags, and the total package is woven bags, and the coagulant for plastics is written on the bag.
(2) Mixing of high-strength wear-resistant plastics.
a The high-strength, wear-resistant and plastic group is equipped with mixed aggregates and coagulant (1 part per bag). The minimum addition amount can be adjusted according to the weather changes and temperature on site. It is packaged separately, and should be poured into the mixer according to the capacity of the compulsory mixer and the construction progress ratio during mixing, and the mixing color is consistent.
b. Add the weighed binding agent and continue stirring (when stirring, add about 2/3 of the weighed binding agent), then add the remaining binding agent according to the specific construction requirements, and then use it after mixing evenly (the mixing time is generally 3min~5min). The bonding agent must be weighed with a weighing instrument (special plastic measuring cup for bonding agent). Strictly controlling the minimum amount of bonding agent is an important measure to ensure excellent material strength and various performance indicators.
The addition amount of C-binding agent is 10% ~ 13% (weight ratio), and the minimum addition amount can be adjusted according to the weather changes and temperature on site.
d The mixed materials must be used up within 40 minutes. The high-strength wear-resistant plastics that have not been used up within 40 minutes are strictly prohibited from adding the binder for the second time. The high-strength and wear-resistant plastic after the initial setting should be discarded.
e The compulsory mixer should be cleaned after each mixing of high-strength wear-resistant plastics to prevent mixing of the bottom material and affecting the construction quality when the compulsory mixer is used again.
(3) High-strength, wear-resistant and plastic construction.
a. The ambient temperature of the material construction site should be controlled between 10℃~30℃, and the humidity should be less than 75%. Appropriate heat preservation measures should be taken when the construction environment temperature in winter is lower than 10℃, and cooling should be taken when the construction environment temperature is higher than 30℃ in summer. Measures, rain-proof measures should be taken for construction in rainy season, and water leakage is strictly prohibited to wash away the plastic after construction.
b When constructing high-strength and wear-resistant plastics, lay colored strips under the construction site to recover the scattered plastics in time to prevent mixing with sundries for reuse.
C Before the high-strength wear-resistant plastic filler, a support plate can be set under the construction site to prevent the high-strength wear-resistant plastic from being scattered. The thickness is measured with a galvanized sheet ruler to ensure the correctness of the primary filler. After the mixed materials are glued into a mass and filled in, first use a wooden hammer or rubber hammer to lightly pound the construction site, and then pull out the pallet and ruler board to compactly pound, first horizontally pound from below, and each hammer is superimposed on 1/3 of the hammer. noodle. Then ramming from bottom to top until dense.
d Check the construction parts with a high-strength wear-resistant plastic breathable drill (steel needle), smooth the higher parts with a trimming knife, and check the flatness with a ruler. If the thickness is not enough, it is necessary to know about 1/3 of the thickness, shave, refill, and ram to prevent the material from delamination and falling off during the operation of the boiler.
e The high-strength wear-resistant plastic surface is trimmed and roughened, and then pierced vertically with a φ 4mm steel needle, which is 1/3 of the construction thickness, and the row spacing and spacing are 150mm~200mm to make the internal bubbles escape.
f High-strength and wear-resistant plastics are strictly prohibited from mixing with water when they are hard: when wiping the surface, it is strictly forbidden to spray water or other dry powder on the constructed surface.
g When constructing inside, stick the high-strength wear-resistant plastic into a mass and carry out construction from bottom to top. High-strength, wear-resistant and plastic construction on the back or top. The high-strength wear-resistant plastic material can be made into blanks on the wooden board first, and the blanks should be laid close to each other, and the blanks should be densely packed and rammed. Other requirements are the same as above. Plastic expansion joints should be preset according to the design regulations, and the furnace wall expansion joints flow into horizontal straight through joints and longitudinal staggered joints. After the overall construction and before hardening, the expansion joints are punched out with thin flat steel according to the spacing required by the design.
(4) Curing of high-strength wear-resistant plastic. During the construction period of the plastic, it is necessary to avoid the vibration of the constructed body as much as possible. After the working surface of the lining body is processed, carry out natural maintenance (the materials in the curing room are strictly prohibited from being damp or sprayed). The curing temperature is 15℃~35℃, in a dry environment (The relative humidity of the air is not more than 70%), and the natural curing period is 5d~7d. Then the oven can be baked according to the oven curve.
Wechat Us 
