Exhaust warm air type boiler unit for open coal pulverization

Abstract

The invention provides an exhaust warm air type boiler unit for open coal pulverization. The boiler unit is used for burning raw coal and is characterized in that a weighing coal feeder is used for measuring, adjusting and controlling raw coal weight corresponding to the amount of boiler supplied coal conveyed into a hearth, an air locking device is used for preventing air cross flow of pulverized coal and maintaining smooth flowing of pulverized coal, a drying agent mixing chamber is connected with a smoke extracting opening and a gas outlet of the pulverized coal collector respectively, the first part of exhaust air extracted from the exhaust air and a part of the smoke extracted from the smoke extracting opening are mixed to be used as a drying agent which is sent into a raw coal pre-drying device, a cold air exhaust-air preheating device is used for preheating environment cold air through an exhaust warm air device to obtain warm air, a part of the warm air is further heated by an air preheater to obtain hot air, a part of the hot air and the other part of the warm air are mixed to be used as primary air, an air-pulverized-coal mixer mixes the primary air and pulverized coal to obtain air-pulverized-coal mixture, and the other part of the hot air is used as secondary air to be directly sent into a pulverized coal burner.

Description

technical field [0001] The invention relates to an open pulverizing exhaust gas heating type boiler unit of a coal-fired power station, in particular to boiler air supply, cold air preheating, pulverizing, pulverized coal combustion and flue gas water recovery technologies. Background technique [0002] Lignite has the characteristics of high moisture, high volatile content, low calorific value, low ash melting point, low abrasiveness and easy spontaneous combustion. Lignite accounts for about 40% of the world's total coal reserves worldwide. my country's lignite accounts for about 16% of the total domestic coal reserves, mainly distributed in the eastern part of Inner Mongolia and the junction of the three northeastern provinces and Yunnan. The lignite in Inner Mongolia and Northeast China belongs to aged lignite, with a total moisture of 25-40%; the lignite in Yunnan belongs to young lignite, with a total moisture of 40-60%, and contains wood fiber. In addition, the pred...

AI Technical Summary

Problems solved by technology

However, compared with conventional bituminous coal boilers, the thermal efficiency of these lignite boilers is lower (about 2 percentage points lower) and the price is higher. This is mainly due to the large amount of flue gas in the lignite boiler, so the heat loss of the boiler exhaust is higher. , the boiler volume is also larger

In addition, the high-moisture coal-fired direct blowing pulverizing system needs to extract high-temperature furnace smoke as the main component of the desiccant of the pulverizing system, which makes the primary air contain a large amount of inert gases such as furnace smoke and water vapor, which makes the stable combustion of the boiler more difficult. difficulty

[0006] In conventional intermediate storage bunker-type pulverizing system boilers, in order to have a certain coal feeding buffer capacity and make the pulverizing process and the combustion process relatively independent, a pulverized coal bunker is often provided. However, for lignite and Zhundong coal with high volatility In terms of coal types, setting up a pulverized coal bunker in the pulverizing system to store flammable, explosive and highly volatile pulverized coal requires high requirements for the explosion-proof design of the pulverized coal bunker, which increases the difficulty of ensuring the safe operation of the pulverizing system

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