The masonry of CFB boilers in power plants is divided into six main areas: cyclone separator furnace wall masonry, rebate furnace wall masonry, furnace chamber outlet, cyclone separator outlet flue furnace wall masonry, dense phase area, air distribution chamber furnace wall masonry, furnace superheater, reheater heating surface and other parts of the masonry, under-bed starter burner masonry.
1. Product introduction
The circulating fluidised bed boiler adopts the clean coal combustion technology with the highest degree of industrialisation. The circulating fluidised bed boiler adopts fluidised combustion and the main structure includes two major parts: the combustion chamber and the circulating return furnace.
2. Circulating fluidised bed boiler features.
1. Wide fuel adaptation, high efficiency
2. Effective desulphurisation, low oxide emissions
3. High combustion intensity, small furnace cross-section
4. Simple fuel and treatment system
5. Easy to realize comprehensive utilization of ash
6. Low failure rate and long operating cycle
3. Refractory materials for circulating fluidised bed boilers
1. Under-bed starter burner (igniter) and fluidised air chamber
Igniter: common castable material
Temperature: design temperature 400-500°C
2. Furnace chamber (transition zone, guard combustion zone)
Materials: high-grade castables, self-flowing corundum castables, steel fibre wear-resistant castables, zirconium corundum wear-resistant castables
Temperature: 900-1000°C
3. Cyclone separator
Material: wear-resistant castables, insulation bricks, insulation castables, wear-resistant refractory castables
Temperature: maximum temperature of central barrel 1100℃, regrouper 900℃
4.Coal saver
Material: inner layer clay bricks, outer layer insulation bricks
Temperature: 200-450℃
5.Water-cooled air chamber
Material: heavy castables, thermal shock resistant wear resistant coroplast
Temperature: 200-450℃
4. Analysis of the causes of refractory materials used in fluidized bed boilers
The loss of fluidized bed boiler lining is mainly due to two major factors.
(1) the lining of the choice of indefinite refractory material itself performance problems.
The choice of irregular refractory materials is unreasonable, the performance of the use of the requirements is one of the reasons for the loss of materials.
(2) The operating conditions of circulating fluidised bed boilers.
Circulating fluidized bed boiler in operation, the high content of solid particles in the flue gas, the flow rate is fast, causing extreme speed, strong uninterrupted scouring wear on the lining, while in long-term operation, frequent start and stop furnace, temperature interaction abrupt changes and other factors under the joint action of a number of strong damage to the lining.
5. Selection of wear-resistant refractory materials
In order to ensure that the refractory material meets the requirements of large circulating fluidised bed boilers, corundum wear-resistant plastic is recommended for the more severely worn structural areas of the boiler.
Corundum wear-resistant plastic is made of good brown corundum, silicon carbide, high alumina clinker, etc. as the main raw material, together with SiO2 powder, phosphoric acid binding agent and some special additives for enhancing its performance, after a strict ratio combination. Its main performance characteristics are high strength, high wear resistance, strong adhesion, easy construction, short construction period, no baking, no cracking and other characteristics, suitable for boiler lining construction and repair of the original casting material lining.
With the continuous promotion and progress of circulating fluidised bed boilers, the selection of refractory materials should be based on the professional configuration of circulating fluidised bed boilers according to the characteristics of their own working conditions. The actual application cases on circulating fluidised bed boilers of different furnace structures that the use of wear-resistant plastic as furnace lining can effectively shorten the construction period, delay wear and tear and prolong the service life in use. Especially in the dense phase area of the furnace chamber, the top of the furnace, the cyclone separator, the flue and other high wear areas have been very good results.
- Our company:
The quality of the bricklaying link of refractory materials for kilns directly determines the effect after they are put into use. From the date of product delivery to the smooth operation of the kiln, Kerui provides comprehensive, meticulous and rigorous technical guidance for refractory construction. The integrated operation mode of Kerui Refractory Service and Technology Center ensures product quality and safe operation.
- Corundum refractories in circulating fluidized bed boiler
Circulating fluidized bed boiler is a thermal equipment used in many industries such as metallurgy, electric power and building materials, which can provide electric and thermal energy.
Corundum castable has higher mechanical strength and abrasion resistance than high alumina refractory castable and mullite refractory castable, and its refractory wear resistance is more prominent than other castables.
Corundum wear-resistant castables for circulating fluidized bed boilers are used in the following parts: combustion chamber, furnace chamber dense phase area, furnace exit flue, furnace bottom, cyclone separator, water-cooled air chamber, etc.