Large supercritical circulating fluidized bed boiler with low primary wind power consumption

Abstract

The invention discloses a large supercritical circulating fluidized bed boiler with low primary wind power consumption and relates to a circulating fluidized bed boiler which is provided with supercritical parameters, used in a thermal power station and provided with a steam turbine generator, wherein the steam turbine generator has a power greater than or equal to 600MW and is assorted with combustible anthracitic coal, low-volatile poor coal, poor coal, soft coal and brown coal. The large supercritical circulating fluidized bed boiler comprises a hearth and a large supercritical circulating fluidized bed boiler of air distributing plates, wherein the hearth is composed of membrane type water-cooled walls in a great ratio of width to depth; the air distributing plates are horizontally arranged and distributed uniformly along the hearth width; each air distributing plate, speed adjusting thermal primary fans of a corresponding section, a cyclone separator, a speed adjusting fluidization fan, a weighing type coal feeder, the membrane type water-cooled walls and an additional heated surface in the hearth form a controllable heat load unit; each speed adjusting thermal primary fan inhales intakes hot air at an air outlet of a binary-chamber rotary type air preheater, pressurizes the hot air and feeds the hot air into a corresponding primary air chamber. Through the large supercritical circulating fluidized bed boiler with low primary wind power consumption, the primary air power consumption is obviously reduced, the pressure loss of a reheating system is obviously reduced, and the heat loss of the set is reduced. Meanwhile, the large supercritical circulating fluidized bed boiler with low primary wind power consumption is modular in structure and easy to design and manufacture large supercritical circulating fluidized bed boilers.

Description

(1) Technical field: [0001] The present invention relates to a large-scale low primary wind power consumption supercritical circulating fluidized bed boiler, which relates to the power of a matching steam turbine generator for a thermal power station using combustible anthracite, low volatile lean coal, lean coal, bituminous coal and lignite. Circulating fluidized bed boilers greater than or equal to 600MW. (two) background technology: [0002] Circulating fluidized bed boilers and pulverized coal boilers are the two most commonly used power plant boilers with different combustion methods. [0003] The combustion temperature of the circulating fluidized bed boiler is usually 850°C to 950°C, which is much lower than the combustion temperature of the pulverized coal furnace. The NOx emission concentration of the circulating fluidized bed boiler is much lower than that of the pulverized coal furnace. In most cases, it can reach the standard without SCR. [0004] The combustion...

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Problems solved by technology

[0008] The second problem encountered in the large-scale promotion of circulating fluidized bed boilers is that the power consumption of the primary wind is high and difficult. The circulating fluidized bed boiler does not need a coal mill, but the power consumption rate of the circulating fluidized bed boiler is usually higher than that of pulverized coal. Furnace, primary wind power consumption is too high is the main reason

There are three main reasons for the high primary air power consumption of existing CFB boilers: 1. The primary air rate is as high as 40% to 60% of the total air volume; 2. The rated primary air pressure is high, up to 32kPa or more High, large energy loss on the air pressure adjustment mechanism; 3. Although the 4-chamber rotary air preheater has been adopted, the primary air leakage rate is still as high as 20%

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