Integrated pulverized coal separation and concentration device of pulverized-coal boiler

Abstract

The invention relates to an integrated pulverized coal separation and concentration device of a pulverized-coal boiler, which comprises an axial type coarse pulverized coal separator of which the bottom is connected with a coal mill (1) by a pulverized coal return pipe (16) and the top is connected with a tangential extraction axial type pulverized coal concentrator; the coarse pulverized coal separator comprises an inlet section (2), a closed inner cylinder body (6) provided with a circular truncated cone bottom (4), a shell (3), a ring-shaped diversion ring (5) and an axial blade (7) of the coarse pulverized coal separator; an outlet on the top of the coarse pulverized coal separator is a tapered necking hole (8); the pulverized coal concentrator comprises a cylindrical shell (9), a pulverized coal concentrator swirl stabilizer (11) provided with a straightening vane (10), an internal inserting type exhaust gas lead-out circular tube (12) and an exhaust gas outlet circular tube (14) which are connected together into a whole, a hot air inlet (15) and a concentration outlet (13); and pulverized coal air flow which has high oxygen quantity and concentration and is formed by mixing hot air coming from the hot air inlet with the pulverized coal coming from the concentration outlet at the end of the concentration outlet is filled into a primary air flow pipeline of the boiler. The invention realizes pulverized coal separation and concentration with high performance and low resistance, and has the advantages of being high in pulverization output, low in pulverization electricity consumption, fine in pulverized coal, good in pulverized coal uniformity, excellent in concentration performance, flexible in adjustment, etc.

Description

technical field [0001] The invention belongs to the field of equipment related to thermal power engineering, and in particular relates to a pulverized-coal boiler that burns high-moisture lignite (the coal-fired base moisture is ≥ 40%) and integrates the pulverized coal separation of the pulverizing system and the pulverized coal concentration function of the combustion system. installation. Background technique [0002] The burial age of lignite is about 15,000 to 40,000 years. According to its geological burial age and carbonization degree, it can be divided into young lignite and old lignite. Aged lignite has deep carbonization degree, compact structure and dark brown appearance. Its calorific value and carbon content are relatively high. The moisture content of the as-received base is generally below 35%, and the volatile content of the dry and ash-free base is generally 40% to 50%. %, the low calorific value on the basis of receipt is between 10MJ / kg and 16MJ / kg. Youn...

AI Technical Summary

Problems solved by technology

For pulverization: when the moisture content of lignite is too high (≥40%) or the calorific value is too low (<9MJ / kg), since the pulverization process requires a large amount of desiccant for drying lignite, the drying of the pulverization system The output, ventilation output and fan lifting pressure head all put forward higher requirements. When the maximum linear speed of the outer edge of the fan coal mill impeller is limited, it is unrealistic to increase the size of the coal mill without limit. Therefore, through Improvement and optimization of the pulverization system It is an effective method to increase the ventilation rate of the fan pulverizer and improve the fineness of coal powder; for combustion: a large amount of desiccant will lead to the air powder mixture coming out of the pulverization system. The concentration of pulverized coal is too low, and at the same time, due to the low concentration of oxygen in the primary air (a considerable proportion of the desiccant is flue gas), the ignition heat required to directly ignite such a pulverized coal flow is relatively high and the theoretical combustion temperature that can be achieved is relatively low. , easily lead to difficulties in stable combustion

At present, except for the No. 1 boiler of Guodian Yangzonghai Power Generation Co., Ltd., my country has no application examples and mature design experience of its own tangentially drawn axial pulverized coal concentrator in the past, and it is impossible to divide the inflow of the concentrator into direct current or direct current. However, with the continuous development and utilization of high-moisture lignite in my country and the export of engineering and technology to foreign countries in the future, the application prospect of this technology will become increasingly broad

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