Special Topic on Circulating Fluidized Beds
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Several common types of circulating fluidized bed boilers and their advantages and disadvantages: a. Circulating fluidized bed boiler with an upper exhaust high-temperature cyclone separator ； 5 v; _+ E# T: W& A: G+ \3 b, w( C+ @ b. Circulating fluidized bed boiler with medium-temperature cyclone separator for exhaust gas treatment ； c. Square water-cooled separator circulating fluidized bed boiler & u, E4 W. P’ v) U+ F d. Circulating fluidized bed boiler $ a) u: A7 @* `, H- V& b The advantages and disadvantages are as follows; 2 Z( F$ A& j4 X# s Fluidized bed boilers can use fuels with a low melting point of ash, which helps to reduce the level of nitrogen oxides in the flue gases. The desulfurizing agents added along with the fuel help to reduce sulfur compounds in the flue gases, thereby minimizing low-temperature corrosion in the rear sections of the boiler. Due to the favorable conditions for fuel ignition and combustion, there is no need to worry about the boiler going out due to a drop in furnace temperature at low loads. Fluidized bed boilers can operate properly within a load range of 25%-110%. Fluidized bed boilers can burn fuel of extremely poor quality; they have a smaller furnace volume, which results in less metal consumption and lower equipment costs. However, they have disadvantages such as low thermal efficiency, rapid wear of the tubes, and high electricity consumption. Several common and typical accidents in circulating fluidized bed boilers include combustion accidents. a. Combustion accidents that frequently occur in circulating fluidized bed boilers ； b. Shutdown of circulating fluidized bed combustion ； c. Slagging in circulating fluidized bed combustion ； / s" z" j6 g0 g% I d. Slagging in other areas of the circulating fluidized bed boiler; e. Combustion explosions in circulating fluidized bed boilers. 4 j* z: g% p% J& ?( _2 J It is a malfunction of the auxiliary equipment! D) C) u! w% ?5 B; e a. Coal hopper clogging fault ； 8 N6 i( v3 C; y7 T b. Jamming fault of the rotating feed valve for the coal drop pipe. 4 n( w' g: U4 w% }# F( ?$ k c. Four-tube leakage fault d. Boiler coking fault ； e. Low-temperature coking fault during ignition ； f. Fault of poor ash discharge in the ash system of the circulating fluidized bed boiler ； g. The impact of limestone desulfurization in the furnace on boiler design and operation. Several common and typical efficiency factors of circulating fluidized bed boilers; Factors affecting the combustion efficiency of circulating fluidized bed boilers: a. Reasons for high carbon content in bottom slag and measures to reduce it ； ) G/ B# u! z7 n, N0 S3 b$ A5 Q9 ?2 E b. Reasons for the high carbon content in fly ash ； S8 ` p, b( s/ B# u c. Measures to reduce the carbon content in the fly ash of circulating fluidized bed boilers. / {/ @" n6 Y2 @+ W$ X* A& g1 F6 U2 l Let’s all contribute and discuss together. I don’t have much knowledge regarding fluidized beds, so I hope everyone will be kind enough to offer their guidance! This post was last edited by bing on 2008-1-21 13:19]
It’s fairly comprehensive, but not very in-depth. The 3 circulating fluidized bed boilers in our plant have been in operation for 3 years since they were put into use, and we have encountered numerous problems: 1. Low-temperature coking ； 2. High-temperature coking ； 3. Tube rupture and wall thinning in the 2nd and 3rd stage superheaters ； 4. Coal blockage fault ； 5. Fault of poor ash discharge ； 6. Problems with the electrostatic dust removal plates result in poor dust removal efficiency, and black smoke is emitted from the chimney ； 7 The casting material is severely falling off.
It’s too broad, and there are too many topics; it’s better to discuss each topic separately
I am engaged in research on fluidized bed gasification technology, specifically high-temperature Wenker fluidized bed technology, which is a foreign technology that has already reached a relatively mature stage
The two major challenges in fluidized bed boilers are: first, fluidization, and second, wear prevention. This brother encountered both of these issues. Points 1, 2, 4, and 5 relate to fluidization and the return of material; in fact, a significant amount of the material that is returned is done using the fluidization air. Point 3.7 pertains to wear prevention, although tube bursts can also be caused by other factors. As for point 6, it has little to do with fluidized beds – it relates to electric field dust removal. However, over the past few years, considerable progress has been made in the design technology, manufacturing processes, and wear prevention methods for fluidized bed boilers, so things have improved a lot.