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

[0006]An object of the present invention is to provide a liquid slag dry centrifugal granulated slag particle size control method to solve the above technical problem; the control method of the invention can effectively prevent the granulated slag particles from being excessively caused to cause a decrease in the vitreous conversion rate thereof. When the slag particles are too small, the granulated slag particles have a low wall and glass transition rate.

[0011]a granulator control unit configured to control centering of a center of the granulator and a center of a slag tube of the buffer device, and meanwhile ensuring a smooth operation of the granulator during high-speed rotation;

[0031]Compared with the prior art, the present invention has the following beneficial effects.

[0032](1) The method for controlling the particle size of the dry granulated slag from the liquid slag provided by the invention can effectively control the particle size of the granulated slag, avoiding the excessive conversion of the granulated slag particles, thereby reducing the conversion rate of the vitreous body and avoiding the granulated slag. The small size of the particles causes the viscous slag particles to adhere to the wall and the glass body has a low conversion rate, which provides a certain reference for industrial applications.

[0033](2) The present invention proposes a structure for ensuring the air outlet at the edge of the granulator in the particle size control, wherein the granulator fixing device has a plurality of tuyères at the top thereof, and the outlet angle intersects the dip angle of the granulator edge. The liquid film or liquid filament formed during the granulation process can be externally broken to enhance the granulation effect.

[0034](3) The present invention proposes a liquid slag dry centrifugal granulation system in particle size control, wherein the rotating shaft is provided with one-stage, two-stage or multi-stage small temperature-resistant blades. During the granulation process, the rotating shaft drives the temperature-resistant blade to rotate at a high speed. On the one hand, the flow power of the air duct is generated, the crushing effect of the granulated edge wind is enhanced, and the cooling of the shaft cooling device to the shaft and the granulator fixing device is accelerated. On the other hand, the temperature-resistant blade can also be used as a rib structure to enhance the overall heat dissipation of the rotating shaft.

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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