Blowing tube material returner used for circulating fluidized bed boiler

Abstract

The invention discloses a blowing tube material return device used for a circulating fluidized bed boiler. The blowing pipe material return device consists of a feeding tube, a discharge tube, the blowing tube material return device, a blowing tube, an air inlet tube and a draught fan, wherein one end of the feeding tube is communicated with the middle part of the blowing tube material return device while the other end is connected with a material return device of the circulating fluidized bed boiler; one end of the discharge tube is communicated with the front end of the blowing tube material return device while the other end is connected into a boiler furnace of the circulating fluidized bed boiler; at least one blowing tube is arranged in the blowing tube material return device; the air inlet of the blowing tube is extended out of the blowing tube material return device and is communicated with the air inlet tube connected with the blowing tube material return device; the other end of the air inlet tube is connected with the draught fan; one end, positioned in the blowing tube material return device, of the blowing tube is closed off by an end cap; and the tube wall positioned in the blowing tube material return device is provided with a plurality of air outlets. The blowing tube material return device serves as a secondary material returning device of the circulating fluidized bed boiler, and solves the problem that ash is emitted from a viewing port and the like of a scraper feeder of the circulating fluidized bed boiler and the problem that a coke is easy to form because the temperature at the bottom of the boiler furnace is over-high, so that the boiler can meet the requirement on production load.

Description

technical field [0001] The invention belongs to the technical field of circulating fluidized bed boilers, and relates to a blowing pipe returning device for circulating fluidized bed boilers. The blowing pipe returning device of the present invention is installed on the rear wall returning device of circulating fluidized bed boilers . Background technique [0002] The coal feeding methods of circulating fluidized bed boilers can generally be divided into two types: front wall coal feeding and rear wall return feeder coal feeding. The two coal feeding methods have their own advantages and disadvantages. The advantage of the front wall coal feeding is that the coal feeding design is simple, the coal feeding stroke is shortened, and the equipment investment and maintenance of the coal feeder are reduced. However, the front wall coal feeding method generally uses a belt Coal feeder, in case of failure, the high-temperature flue gas will flow back, which will cause the belt coal...

AI Technical Summary

Problems solved by technology

[0005] 1. The circulating fluidized bed boiler cannot reach full load operation

The bed temperature of the boiler will reach 950°C when a small amount of coal is fed. If coal is added continuously, the bed temperature will rise to the coking temperature. Unfortunately, the bed temperature can only be cooled by increasing the air volume once. However, this will increase the load of the boiler to a limited extent. Increase the oxygen content of the flue gas, sometimes reaching more than 10%, which increases the operating cost of the boiler, seriously deviates from the scope of economic operation, and even makes the production passive

The reason for the above results is that due to the high design of the boiler furnace, the external circulation of fly ash is not smooth, and the ash particles with larger particle sizes cannot reach the flue gas outlet, let alone enter the separator for separation. The ash particle size separated by the separator is too large. fine, and because the distance between the coal outlet of the boiler and the air cap is relatively high, the fine ash cannot reach the dense phase area of ​​the bed under the action of the primary wind and the induced wind, and cannot cool the bed temperature, so that the bed temperature is low under the condition of low coal feed reach high bed temperature

[0006] 2. Dust continuously emerges from the observation hole of the scraper coal feeder and the connection between the belt coal feeder and the scraper coal feeder, resulting in a large amount of dust accumulation on the platform of the boiler scraper coal feeder. In severe cases, people cannot approach. It affects the normal inspection, maintenance and overhaul, which not only greatly affects the environmental sanitation of the workplace, but also brings unsafe factors to the continuous, safe and stable operation of the boiler, affecting safe and civilized production

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