Blast furnace blown pulverized coal and air heating furnace air/coal gas series connection preheating process and system

Abstract

The invention relates to a blast furnace blown pulverized coal and air heating furnace air / coal gas series connection preheating process and system. The high-temperature flue gas of an air heating furnace firstly enters a pulverized coal preheating system to be used for preheating of pulverized coal, then the flue gas after heat exchange enters an air / coal gas preheating system to be used for preheating of air and / or coal gas so as to realize grading utilization of the waste heat of the high-temperature flue gas. The system comprises the air heating furnace, the pulverized coal preheating system, the air / coal gas preheating system and a chimney, wherein the pulverized coal preheating system comprises a combustion furnace and a pulverized coal preheater, the air / coal gas preheating system comprises an air preheater and / or a coal gas preheater. According to the blast furnace blown pulverized coal and air heating furnace air / coal gas series connection preheating process and system, the series connection preheating system is arranged, the high-temperature flue gas of the air heating furnace is used for preheating the pulverized coal firstly and then is used for preheating the air and / or the coal gas, so that grading utilization of the flue gas of the air heating furnace is achieved, high-temperature preheating of the pulverized coal can be realized, high-temperature preheating of the air and / or the coal gas also can be realized, finally, the waste heat in the flue gas can be fully recovered, and the purposes of energy conservation and consumption reduction are realized.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of waste heat of blast furnace hot blast stove flue gas, and in particular to a process and system for preheating in series of blast furnace pulverized coal injection and hot blast stove air / coal gas. Background technique [0002] High energy consumption, high cost, coke shortage, and deterioration of the production environment are common problems in the world's ironmaking industry. The energy consumption of ironmaking has become an important part of the cost per ton of steel, and the discharge of pollutants also has a serious impact on the environment. Therefore, energy saving and environmental protection in ironmaking are very important to the healthy development of the entire iron and steel industry. [0003] From a global perspective, the resources of coking coal are increasingly scarce, and the whole world feels the crisis of coking coal resources. Although our country is r...

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Problems solved by technology

Due to multiple restrictions such as the heat-resistant temperature of the coal mill body, the safe operating temperature of pulverized coal, and the heat-resistant temperature of the subsequent powder collection bag, this process cannot achieve a higher preheating temperature.

[0007] The Chinese patent application with the publication number CN102605119A discloses a pulverized coal conveying and preheating process device in the pulverized coal injection process of the blast furnace. Although the pulverized coal conveying and preheating process device preheats the pulverized coal, it does not reuse High temperature gas after preheating, causing waste of energy

[0008] In the conventional pulverized coal preheating system, in order to ensure that the pulverized coal is preheated to a higher temperature (≥300°C), it is necessary to increase the temperature of the flue gas inlet of the pulverized coal preheater, but the flue gas outlet temperature of the pulverized coal preheater It will also be relatively high. If the heat of the flue gas cannot be used well, a lot of heat will be wasted

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