Circulating fluidized bed boiler technology for pure-burning low heating value coal gangue

Abstract

The invention provides a circulating fluidized bed boiler technology for pure-burning low heating value coal gangue, mainly solving the problems that the gangue cannot be purely burnt and a large amount of coal is required to be doped, sufficient burning can be carried out after the doped burnt heat value reaches over 3000 kcal / kg, the output of purely-burnt gangue cannot reach a specified value even if the gangue is purely burnt, and the gangue is seriously worn in the prior art. The circulating fluidized bed boiler technology which is mainly adopted by the invention has the characteristics of low wind speed, high bed temperature, large bed surface, thick material layer and far slag discharge and consists of improvement on a circulating fluidized bed boiler and burning process parameters of the pure-burning low heating value coal gangue.

Description

technical field [0001] The invention belongs to the technical field of circulating fluidized bed boilers, and in particular relates to a circulating fluidized bed boiler technology for purely burning coal gangue with low calorific value. Background technique [0002] As my country's coal production increases year by year, coal gangue accumulates, accounting for about 10% to 15% of coal production. At present, there are more than 1,500 piles of coal gangue, accounting for about 4 billion tons, covering an area of ​​more than 13,000 hectares, and increasing at a rate of about 100 million tons every year. Because a large amount of coal gangue is accumulated and cannot be used and disposed of, the gangue hill will spontaneously ignite and cause a fire, or collapse in the rainy season, silting up the river and causing disasters, which has brought huge pollution to the environment. Therefore, rational use of coal gangue can protect the environment and protect the environment. Its...

AI Technical Summary

Problems solved by technology

[0004]The use of existing circulating fluidized bed boilers cannot purely burn gangue, the thermal efficiency is low, and a large amount of coal must be blended, and the calorific value after blending can reach more than 3000 kcal / kg In order to fully burn; even if pure gangue is burned, the output cannot reach the specified value, and the wear is serious. The reasons are as follows:

[0005] 1. Since gangue is harder than other types of coal, the ash content in coal is more and the calorific value is lower. The wear of the heating surface of the circulating fluidized bed is mainly caused by the collision between the ash and the pipe. Since the cross-sectional size and the anti-wear structure of the ordinary fluidized bed cannot meet the requirements, if it is operated for a long time, the heating surface will be very serious. Wear and tear, resulting in boiler inoperability

[0006] 2. When burning ordinary coal, the bed temperature is controlled at 900°C, and the material layer is controlled at 500-600 mmm. This bed temperature and material layer cannot guarantee the combustion stability of coal gangue and embers of carbon particles

[0007] 3. Generally, the designed primary air ratio of circulating fluidized bed boilers is about 60%. On the one hand, due to the large proportion of gangue, and on the other hand, the volatile content of gangue is also low, and the proportion of combustion in the lower part must increase, and the primary air volume of 60% cannot guarantee the burning of gangue

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