| Product thermal capacity: | 35-75 t/h |
| Working pressure: | 1.25-5.3 MPA |
| Outlet temperature: | 194-485 ℃ |
| Available fuel: | Bituminous coal, anthracite, meagre coal, lignite, gangue, waste, sludge |
| Available industries: | Chemical, food, tobacco, textile, printing and dyeing, feed, medicine, building material, wine, rubber, hospital |
Introduction of CFB (circulating fluidized bed) coal-fired steam boiler
The circulating fluidized bed boiler adopts the clean coal combustion technology with the highest degree of industrialization. The circulating fluidized bed boiler adopts fluidized combustion, and its main structure consists of combustion chamber (including dense phase zone and dilute phase zone) and circulating return furnace (including high temperature gas-solid separator and return material system).
Circulating fluidized bed boiler is developed on the basis of bubbling bed boiler (fluidized bed boiler), so some theories and concepts of bubbling bed can be used in circulating fluidized bed boiler. But there is a big difference. The early circulating fluidized bed boiler has higher fluidization speed, so it is called fast circulating fluidized bed boiler. The basic theory of fast bed can also be used in CFB boiler. The basic theory of bubbling bed and fast bed has been studied for a long time, and a certain theory has been formed.To understand the principle of circulating fluidized bed, it is necessary to understand the theory of bubbling bed and fast bed and the dynamic characteristics, combustion characteristics and heat transfer characteristics of materials from bubbling bed, turbulent bed and fast bed.
Feature of CFB（circulating fluidized bed ）coal-fired hot water boiler
High combustion intensity and small cross section area: The high heat load of furnace section area is another main advantage of CFB boiler. The heat load of the section is about 3.5 ~ 4.5MW/m2, close to or higher than that of the pulverized coal boiler. Under the same heat load, the cross-sectional area of the furnace needed by the bubbling fluidized bed boiler is 2-3 times larger than that of the circulating fluidized bed boiler.
High combustion efficiency: The combustion efficiency of circulating fluidized bed boiler is higher than that of bubbling fluidized bed boiler, which can be compared with pulverized coal boiler in the range of 95-99%. The high combustion efficiency of CFB boiler is due to the following feature: good gas-solid mixing; high combustion rate, followed by fly ash recycling combustion.
The range of load regulation is large, and load regulation is fast: When the load changes, only the amount of coal, air and material circulation needs to be adjusted, and the separate-bed fire-pressing technology is not needed as the bubble fluidized bed boiler does. Also, unlike coal pulverized boilers, oil should be fired at low load to maintain stable combustion. Generally speaking, the load ratio of circulating fluidized bed boiler can reach (3~4):1. The load regulation rate is also very fast, usually up to 4% per minute.
Energy-saving retrofit of circulating fluidized bed boiler
1. Add fuel economizer;
2. Installation of condensing gas boiler energy saver;
3. Adopt condensing waste heat recovery boiler technology;
4. The tail part of the boiler adopts heat recovery technology of heat pipe.
