A Method for Realizing Ultra-low Emission of Nox from Circulating Fluidized Bed Boiler
A circulating fluidized bed and boiler technology, which is applied in the direction of fluidized bed combustion equipment, combustion methods, fuel burned in a molten state, etc., can solve problems such as escape, reduce boiler thermal efficiency, and regular replacement of catalysts, and achieve reduction of original NOx emissions Effect
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Embodiment 1
[0039] Example 1: On a 90t / h circulating fluidized bed boiler, the change of NOx emission before and after the improvement of the separator was compared. The boiler uses high-quality bituminous coal, with a low calorific value of 5100-5200kcal / kg, an ash content of about 25%, a sulfur content of 0.4-0.9%, and a volatile content of 32-37% on a dry, ash-free basis.
[0040] The separator has been improved on this boiler, and the efficiency of the separator has been significantly improved. The improved separator corresponds to d 50 = 10 μm, d 90 = 54 μm. Under rated working conditions, the boiler meets the following parameters during operation: the air pressure in the boiler air chamber is about 6.2kPa, the differential pressure at the upper part of the furnace is about 1000Pa; the bed temperature is about 865°C. At this time, the original NOx emission of the boiler is 80~100mg / m 3 ,
[0041] And when a low-efficiency separator is used, its corresponding d 50 = 22 μm, d 90 ...
Embodiment 2
[0042] Example 2: A comparative experiment of bed material inventory adjustment was carried out on a 150t / h low-volatile bituminous coal circulating fluidized bed boiler. The boiler uses a fuel with a calorific value of 4500-4800kcal / kg, an ash content of about 30-33%, and a dry ash-free base volatile content of 21-23%.
[0043] Under rated working conditions, the air pressure in the boiler air chamber is controlled at 7.5-8.0kPa, the differential pressure at the upper part of the furnace is 1.4-1.5kPa, the bed temperature is around 878°C, and the oxygen content of the flue gas at the furnace outlet is controlled at less than 3.25%. At this time, the original NOx emission of the boiler is 50mg / m 3 .
[0044] When the wind pressure in the air chamber is 6.0-6.5kPa, the differential pressure at the upper part of the furnace is 1.0-1.1kPa, and the bed temperature is around 895°C, the original NOx emission rises to 75mg / m 3 .
Embodiment 3
[0045] Example 3: On a 150 / h high-quality bituminous coal-fired circulating fluidized bed boiler, a comparative experiment was carried out on the effect of bed temperature on NOx formation. The boiler uses Shenhua coal, the calorific value of the fuel is about 5000kcal / kg, the ash content is about 16%, the dry ash-free base volatile matter is about 36%, and the sulfur content is about 0.6%.
[0046] Under the rated working conditions, the air pressure of the boiler air chamber is controlled at 7.7-8.0kPa, the differential pressure at the upper part of the furnace is 1.6-1.8kPa, and when the bed temperature is 820-830°C, the original NOx emission is 50-60mg / m 3 .
[0047] Under rated working conditions, the air pressure in the air chamber is controlled at about 7.0kPa, the differential pressure at the upper part of the furnace is 1.3-1.4kPa, and when the bed temperature is 830-840°C, the original NOx emission increases to 60-70mg / m 3 ;
[0048] All other conditions remain the...
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