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1、220t / h circulating fluidized bed boiler Analysis Article Abstract: The focus of analysis of 220t / h circulating fluidized bed operation of the existing problems and proposed solutions. Keywords: circulating fluidized bed operation 1. Preface Circulating fluidized bed boiler with high efficiency,
2、low pollution, low cost and so on. Circulating fluidized bed combustion is between layer between the burning and the combustion chamber of a combustion technology is the use of fluidized combustion has many advantages: fuel applicability of Canton; high combustion efficiency; burning intensity, temp
3、erature, evenly distributed; As a result of staged combustion temperature, high efficiency desulfurization, flue gas SO2 and NOX emissions of less; large proportion of load regulation; ash comprehensive utilization of good performance. Because of these advantages, the past 10 years, Chinas circulati
4、ng fluidized bed boiler has been rapid development. But look at our operation of circulating fluidized bed boilers, high failure rate, run a short cycle has become a common phenomenon. Mainly in coal feeding system failure, slag failure, the wind chamber leakage materials. The following companies co
5、mbined ALUMINUM Hongjun Huo Coal Power Plant of Wuhan Boiler Factory production of two 220t / h circulating fluidized bed boiler operation, analysis of the circulating fluidized bed boiler common problems and find solutions. 2. Equipment Overview Hongjun Huo Coal Furnace No. 1,2 ALUMINUM companys pl
6、ant of Wuhan Boiler Factory production of circulating fluidized bed boiler. Department of High-Voltage, Single-chamber, balanced ventilation, natural circulation drum furnace, water wall membrane, using steam-cooled cyclone for gas-solid separation of interior decoration. Boiler mainly consists of f
7、our parts: the combustion chamber, high temperature cyclone, back and tail material convection flue sealing device. Combustion chamber is located in the boiler front, bottom of the back wall of the water-cooled water-wall bending fabric panels and wind chamber air. After the two parallel arrangement
8、 of the combustion chamber diameter of 5 meters high temperature cyclone separator. Sealing back feeding device in the cyclone, the cyclone and the combustion chamber and connected. The combustion chamber, cyclone, and the seal constitutes a particle feeding device back to the circuit. Tail convecti
9、on boiler flue and then back, around the flue and the roof from the upper-wall composition, its arrangement within the flue gas flow in turn has three superheater and a superheater, the flue inside the lower part of the order furnished with economizer and lying type air preheater, a secondary air se
10、paration arrangement. Pot using single-stage evaporation system, down pipe combination of centralized and decentralized way of water supply. Superheated steam temperature by using two spray temperature regulation. Under the bed boiler fire, water, cold rooms start under the arrangement of two burner
11、s. Each chamber is equipped with a simple mechanical atomized oil gun. Ignition Wind quote from the primary air exit. Ignition will be the primary air heated to around 900 , fire-resistant insulating layer thickness of 200mm. Furnace slag slag cooling device using drum, bucket by a chain conveyor in
12、to the slag storage. Ash Cooler start burner arranged below the parallel arrangement of three. In order to ensure good heat transfer tail effect of heating surface in the superheater, economizer air preheater arrangement of steam sootblowers Department. Boiler is equipped with a fan one, the second
13、one fan, two induced draft fan, high pressure stream of fan two. No. 2 furnace at the February 17, 2005 after 72-hour trial run into production, No. 1 furnace at the August 13, 2005 after 72-hour trial run of production. 3. Problems and Analysis 3.1 burner design unreasonable, start a long time. Und
14、er the bed boiler ignition mode, a total of two oil guns arranged. Each contribute to 900kg / h, which can carry 12% BMCR load. Burner by mixing air into the circumferential direction at two levels, each level 16 draft, with the flue gas generator axis angle 60 into. Due to uneven air flow outlet 16
15、, causing the flame deflection. The burner air distribution device burnt. In order to avoid burnout air distribution devices, was forced to contribute to reduced oil gun 500kg / h. But the start-up time up to 11 hours. Waste a lot of fuel. Measures taken: (1) using a thin material layer to start. Th
16、e thickness of normal operation of the boiler feed maintained at 600 800mm. Material layer added to the boiler starts 500mm. (2) using micro-flow-based startup mode. Cold Test of the minimum critical flow of air volume 100000m3 / h, obviously better than the circulating fluidized bed boiler with the
17、 capacity level of critical fluidization air volume is too large. In order to reduce heat loss, start with 80000m3 / h flow of air flow, with the increase of bed temperature gradually increased until the air flow is greater than the critical flow of air volume. (3) early vote in coal combustion. Hon
18、gjun Huo Coal-fired power plants ALUMINUM company is Huolinhe open-pit lignite. As the burning of lignite at 250 450 between, so do not wait until the bed temperature reaches 600 when the cast of coal. Practice has proved that the average bed temperature reaches 280 can be cast coal combustion. Bed
19、temperature reaches 600 , you can burn off the oil stability. This greatly reduces the amount of fuel. For a high ignition temperature of fuel burning power plant, the boiler start-up phase can be used as a primer lignite coal, increased bed temperature. Cast coal bed temperature reached the design
20、temperature of coal, coal reburning using design. Lignite coal is used as a primer-saving technology, circulating fluidized bed boiler measures for very promising way. To contribute to reducing the oil through the use of guns, thin material layer, micro-flow-based, early investment units of coal and
21、 other means to achieve fast and stable start, and to reduce the start-up fuel consumption. Reposted elsewhere in the paper for free download http:/ 3.2 The issue of coal bunker coal shed. (1) cause analysis. Coal storage shed coal, circulating fluidized bed boiler bypass is the most common failures
22、. From the perspective of two 220t/hCFB furnace run coal bunker coal shed accident rate is high and the highest class as much as 20 times. A serious threat to stable operation of the unit. The electricity sector in accordance with the current design requirements, finished product warehouse of the vo
23、lume of coal should be able to meet the boiler at least 8 hours or more to contribute to the amount of demand for coal storage. Finished product of coal piled up in the cone of coal by the coal bin in the extrusion, so that between the coal particles, coal grains and produce friction between the coa
24、l bin wall. closer to his mouth under the coal the greater the friction and extrusion pressure. So, the next of coal at the coal port about 1m more easily bypass. Also in the larger water within a certain range, coal, grain The adhesion between the greater. so that the deterioration of coal liquid.
25、Huolinhe receive the base moisture lignite coal 30%, increased coal bunker coal shed failure. Of coal, the easier the next block of coal smaller population, the German request of the coal-burning bituminous coal in the mouth when the width of greater than or equal 1000mm, when burning lignite than o
26、r equal to 1200mm, the length is less than the mouth of coal 1200mm, coal bunker with coal feeder connected part of the metal bucket processed into hyperbolic shape. domestic circulating fluidized bed boiler coal bunker are mostly cube cone, under the port section of coal smaller (Wu Guo 220t/hCFB c
27、oal furnace coal bin under the mouth of 510mm 510mm ). (2) to take measures. 1) In the coal bin wall installation of wall-type electric vibration machine, on a regular basis rapping. 2) Coal storage device to install hydraulic loosening. 3) on a regular basis to reduce coal-bit. Such measures have g
28、reatly alleviated the coal shed failure. But does not fundamentally solve the problem. Institute should give full consideration to the issue of coal storage shed coal will be the next coal port is designed to hyperbolic type. And to consider the installation of coal bunker wall polyethylene plastic
29、sheeting and other methods to prevent sticking of coal. 3.3 The coal feeding system (1) to the coal-burning machine. Hongjun Huo Coal Company Electric 220t/hCFB ALUMINUM coal boiler pressure weighing machine for sealing belt to the coal feeder. This compared with coal feeder screw and buried scraper
30、 coal feeder Coal machine and high reliability. But it should be noted that coal port should not be pressure, or high-temperature flue gas may be burned-out anti-channeling belt. Units have two years to put into operation coal due to water-cooled screen blasting and coal burning eyes leaking bucket.
31、 Response measures: 1) coal drop pipe to install Fast off valve. Although exports of coal feeder designed electric valve, but in order to increase the safety of coal feeder coal drop pipe can be installed quickly open and close pneumatic valve, this valve and the coal feeder temperature interlock. W
32、hen the time-temperature coal feeder This valve quickly closed, parallel jump coal feeder .2) set multicast coal booster fan. (2) to the coal feeder over-temperature. Commissioning the unit occurred during coal feeder-temperature phenomena. Air preheater inlet heating method uses a hot air recircula
33、tion. Recycling the door is bound to cause a loose fan outlet temperature is too high. To the coal feeder connected to a sealed air Fan exports of coal feeder over-temperature. was forced to block the hot air recirculation piping. for the use of sealed belt weighing machine type coal boiler, air pre
34、heater inlet heating should not be used hot air recirculation heating. (3) to the coal feeder and the import and export of electric gate door interlock DCS system is only to start, there is no branch-start function. Stop coal machine in order to prevent spontaneous combustion of coal in the coal bel
35、t of coal will have to pull an empty coal belt. When operations would have to go step by step in-place operation, very inconvenient. 3.4 Wind Chamber leakage bed material. 2800 8800mm rectangular water-cooled air distribution panel layout with 855 Bell-type hood with large diameter, spacing, S1 = S2
36、 = 160mm, each hood by connecting pipe and the hood the first two parts, hood with holes around the lateral and pore size 15 .5 mm. Hood directly on the base did not use any connection. Hood has been in operation due to the wind turned, the wind spilling into the room a large number of bed material
37、was forced to shutdown many times. Taken after the hood and the base spot, running is much better off. Factories such as the use of hood does not occur in connection with the base rib hood was once the wind turned phenomenon. 3.5 cloth fabric wind wind board is seriously imbalanced. Wind resistance
38、is too small fabric panel (data see table below), weakening the wind steady flow Pressure chamber role. Fluidization air flow in the 50000Nm3 / h, the Central has been completely fluid, but basically at a standstill around the wall. This must be a larger flow of air volume (100000m3 / h) to ensure t
39、he normal flow of bed material. A higher flow of air flow consequences are as follows: 1. Low-load operation can only be more difficult to bring 30% B-ECR. Time of bed temperature has dropped to 650 . 2. Boiler start a large quantity of heat loss when the wind than the more, start slow. 3. heating s
40、urface wear increased. 4. Wind Electrical and consumption increase. In addition to transforming hood not a better way. 3.6 Measurement point problem As the thermocouple thermometer is expensive, in the dense phase region into the depth of measurement points is often not enough. This has resulted in
41、temperature readings deviate from the true value. To run the personnel to operate to determine a certain impact. This requires measuring point must be inserted into the furnace 100 150mm length, taking into account the wear and tear. Wear at the temperature to install casing, will not affect the hea
42、t transfer has solved the issue of thermometer wear. Positive regional pressure measurement is frequently blocked, in addition to use of blockades outside the blowing device must also be periodically purging. 3.7 large-scale circulating fluidized bed boilers are generally equipped with feeding syste
43、m. The first is used to lay at the end of Kai furnace feed to reduce the manual labor intensity, and second, prepared by gray ash storage can be used in an emergency situation (room air leakage material, coal quality change material layer thinning, etc.). lignite combustion characteristics are easil
44、y broken after the slag are in 6mm below the fundamental without screening fine particles can be used as boiler start-bed material. Residue positions in the lower part of a pipeline directly to the furnace pneumatic conveying bed material is more savings in manpower and material resources. References: Jun-Fu Lu Guang-Xi Yue Zhang Jiansheng, circulating fluidized bed boiler operation and maintenance. Reposted elsewhere in the paper for free download http:/