The circulating fluidized bed boiler is in operation, and the material in the boiler furnace is in the circulating flow state. Among them, the materials containing fuel, fuel ash, limestone and their reaction products are part of the external circulation in the circulation process, that is, in the closed circulation loop of the furnace - cyclone separator - return valve - furnace, they are in a constant high-speed circulation fluidizing state; Part of it is internal circulation, that is, the material with larger particles falls back in the furnace under the action of gravity. If the selection of refractory and wear-resistant materials is not suitable, the construction quality is not high, and the oven quality is not up to the specification requirements, it will seriously affect the normal operation of the CFB boiler.
1, wear-resistant refractory castable construction
Castable construction focuses on pin welding, asphalt brushing, water mixing, mold fixing, vibration, release protection, size assurance, accurate measurement points and other links, in strict accordance with the requirements of material manufacturers and boiler factories.
1) Pin, nail installation
Before water pressure, the pins knocked off in the process of transportation and installation and the welding joint of the heating surface should be repaired, and the pins should be properly lengthened and welded at the coal feed port, the return port, the air pipe port and the inflection point of the upper part of the furnace to ensure that the pins are arranged according to the design density. Before pouring, apply 1 layer of asphalt paint with thickness > 1mm to all embedded metal parts, nails and other metal surfaces or bandage with combustible materials.
2) Ingredients, water distribution, mixing control
The ingredients should be weighed and water distributed strictly according to the requirements of the material specification of the material manufacturer, and the measurement should be accurate. The water used for stirring castable is clean water (such as drinking water), with a pH of 6 to 8. Add material and water pay attention to the order and mixing and mixing time, do not allow to add water at will, do not allow any advance or extend the mixing time, the water should not be added to one place, the castable should be fully mixed. It is necessary to add steel fiber in the process of adding water mixing, and shall not be incorporated into clusters. After the stirred castable that meets the requirements is poured out, it is immediately removed. No matter whether the castable is removed or not after pouring out of the barrel, it is not allowed to return to the barrel for repeated mixing. After each construction, the barrel should be cleaned in time to prepare for the next use; Record the amount of water added to the ingredients, mixing time and other records.