A milling and air conditioning system combined with waste heat utilization and a milling and air conditioning method

Abstract

The invention provides a powder manufacturing and air adjusting system utilizing waste heat and a powder manufacturing and air adjusting method. The powder manufacturing and air adjusting system utilizing the waste heat comprises an air pre-heater (28), an air supplying and heating device (30) used before air preheating, a hot primary air phase change cooler (11), a coal mill (13), a dust remover (24), an air induction fan (23) and a low temperature heater (22) for condensation water. According to the invention, on the premise of guaranteeing the system safety, various automatic adjustment measures are taken for improving the adjustment ability of the powder manufacturing system greatly, and the coupling problem of the powder manufacturing capacity and the drying capacity of existing powder manufacturing systems of boilers is solved; comprehensive utilization of the waste heat of smoke and hot primary air is realized, the drying energy for the powder manufacturing system can be utilized optimally, and the utilization efficiency of the waste heat can be improved.

Description

technical field [0001] The invention relates to thermal power generation technology, in particular to a pulverizing air conditioning system and a pulverizing air conditioning method combined with waste heat utilization. Background technique [0002] Most of the pulverizing systems of coal-fired power plants have a coupling relationship between pulverizing volume and drying volume. Under a certain hot primary air temperature, increasing the hot primary air supply of the coal mill can increase the pulverization capacity, but it may cause excessive drying of coal powder, and the outlet air temperature of the coal pulverizer is too high, which will affect the pulverization system and combustion system The safety of the equipment; reducing the hot primary air supply of the coal mill can control the outlet air temperature of the coal mill within the allowable range, but it may cause insufficient pulverization capacity carried by the primary air. The impact of this coupling proble...

AI Technical Summary

Problems solved by technology

The air-water heat exchanger has a large lag in adjusting the heat transfer load by adjusting the flow of condensed water, which is not conducive to the safe operation of the pulverizing system

Moreover, the temperature of the primary air at the outlet of the air conditioner is much higher than the saturation temperature under the pressure of the condensed water, and there is a risk of the condensed water vaporizing and causing serious overpressure, which poses a great threat to the safe operation of the condensed water system.

In addition, this scheme degrades and uses the heat with higher primary air temperature, resulting in excessive loss

Installing a flue gas cooler on the flue after the air preheater can also reduce the temperature rise of the exhaust gas at the outlet of the air preheater caused by the bypass of the cold primary air, but this method also reduces the quality of waste heat utilization

[0006] On the other hand, when the boiler is in the process of ignition or low-load operation, due to the low temperature of the flue gas before the air preheater, the temperature of the hot primary air is low, the combustion stability of the pulverized coal burner becomes poor, and the combustion efficiency of the boiler is low. The transition period of auxiliary fuel combustion is extended, the pollution of denitrification catalyst and dust collector is aggravated, and the temperature of hot primary air is reduced, which will also reduce the coal drying capacity, which will aggravate the above phenomenon

[0007] In addition, at present, most of the heat required for pulverized coal drying comes from the high-quality heat generated by coal combustion. If the raw coal can be dried with waste heat with low exhaust gas temperature, and the moisture contained in the incoming coal can be partially vaporized, the available calorific value of coal will be greatly improved. Improvement, great energy saving potential for coal with high water content

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