Method for controlling particle size of dry centrifugal granulated slag particles from liquid slag

Abstract

A method for controlling a particle size of dry centrifugal granulated slag from liquid slag, which is based on a dry centrifugal granulation system for liquid slag, wherein the dry centrifugal granulation system for the liquid slag includes: a temperature control unit, a flow control unit, and a granulator control unit; wherein the temperature control unit is configured to control a high-temperature slag in the liquid slag buffer device to maintain a first set temperature range, and control a temperature of an outflow slag of the buffer device to maintain a second set temperature range; a flow control unit configured to control a flow rate of the high-temperature slag flowing out of the buffer device in a set range to ensure smoothness of the flow; a granulator control unit configured to ensure a smooth operation of the granulator during high-speed rotation.

Description

CROSS REFERENCE OF RELATED APPLICATION[0001]This is a U.S. National Stage under 35 U.S.C 371 of the International Application PCT / CN2018 / 096520, filed Jul. 20, 2018, which claims priority under 35 U.S.C. 119(a-d) to CN 201810159868.4, filed Feb. 26, 2018.BACKGROUND OF THE PRESENT INVENTIONField of Invention[0002]The present invention relates to the technical field of high-temperature liquid slag waste heat recovery, and more particular to a method for controlling particle size of dry centrifugal granulated slag particle from liquid slag.Description of Related Arts[0003]China is currently the largest steel producer all over the world. In 2016, China's pig iron yield was about 0.701 billion tons, accounting for about 60% of the world's total production. In the process of smelting pig iron, blast furnace slag containing huge heat was produced. The blast furnace slag is generally discharged at a temperature at a range of 1400-1550° C. Each ton of the slag contains (1260 to 1880)×103 kJ ...

AI Technical Summary

Benefits of technology

The present invention provides a method for controlling the particle size of dry granulated slag particles. This method can prevent excessive conversion of granulated slag particles, reducing the conversion rate of the vitreous body and avoiding the need for excessive materials. The method includes a granulator control unit that ensures smooth operation of the granulator during high-speed rotation, while a rotating shaft with temperature-resistant blades enhances the crushing effect and cooling of the shaft and granulator fixing device. Compared to prior art, the present invention has the benefits of higher efficiency and reduced costs for industrial applications.

Problems solved by technology

The dry slag pit cooling method generates a large amount of water vapor while cooling, and at the same time releases a large amount of H2S gas and SO2 gas, which corrodes the building, destroying the equipment and deteriorating the working environment.

The water slag method wastes a lot of water resources during the treatment process, generates harmful gases such as SO2 and H2S, and cannot effectively recover high-quality waste heat resources contained in the high-temperature liquid slag.

At present, these treatment methods are not capable of meeting the urgent requirements of energy saving and emission reduction in the current steel industry, and the dry centrifugal granulation method is widely favored due to low system energy consumption, small and uniform particle size, and high added value of products.

However, if the particle size of the granulated slag is too large, the cooling rate of the molten slag particles decreases during the heat exchange with the heat transfer medium in the space, and the crystal phase transition is easy, resulting in a decrease in the glass transition rate and affecting the high-efficiency resource utilization of the slag particles; if the particle size of the granulated slag particles is too small, the flight distance is too long, and it is easy to hit the granulated warehouse wall surface in the molten state or the external condensed molten state to adhere thereto, and Easy to bond into large pieces.

If the high-temperature slag particles are bonded to the wall surface and bonded into a large block, on the one hand, it is easy to cause over-temperature and corrosion of the granulated warehouse wall surface, and the large block that is bonded after cooling is not easy to clean, which brings the pole for maintenance work.

On the other hand, the slag particles bonded into a large block are slowly cooled in the granulated space and have sufficient time to crystallize, thereby reducing the glass transition rate and affecting its efficient resource utilization.

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