Patent Application
20200208230
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.
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 of sensible heat, equivalent to 60 kg of standard coal. Under the conventional iron making technology in China, while producing one ton of pig iron, 0.3 tons by product of blast furnace slag are produced, calculated by the current production of 0.701 billion tons, which can be converted into blast furnace slag of more than 210 million tons, and the sensible heat thereof is equivalent to about 12.618 million tons of standard coal.
The dry slag pit cooling method and the water flush slag method are the most common method for treating blast furnace slag in China. 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.
In the dry centrifugal granulation process, the liquid slag drops onto the surface of the high-speed rotating granulator, and is scooped out under the action of centrifugal force and friction force to form small droplets under the action of surface tension. These tiny liquids The droplets are forced to convective heat transfer with a heat transfer medium (generally air) in the space, and perform radiative heat exchange with the surrounding environment causes the temperature of the small droplets to decrease, and then a phase change occurs to form a solidified layer. As the temperature is further reduced, the droplets gradually transform into solid small particles. 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. Therefore, in order to ensure the normal progress of dry centrifugal granulation, it is urgent to provide a liquid slag dry centrifugal granulated slag particle size control method.
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.
In order to achieve the above object, a technical solution adopted by the present invention is as follows.
A method for controlling a particle size of dry centrifugal granulated slag from liquid slag is provided, which is based on a dry centrifugal granulation system for liquid slag, wherein the dry centrifugal granulation system for the liquid slag comprises: 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 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;
the method for controlling a particle size of dry centrifugal granulated slag from liquid slag specifically comprises steps of:
step (1) through the temperature control unit, the flow control unit and the granulator control unit, controlling a temperature and a flow rate of a liquid slag falling into the granulator, and ensuring that the granulator and the slag tube are centered and smooth without shaking; then commissioning; through a process test, adjusting a rotation speed of the granulator, an outflow flow rate, a viscosity temperature characteristic, a granulator structure, a granulator size, a granulator surface roughness, a granulator edge wind speed and angle, so as to obtain relationships between a particle size of the granulated slag and the rotation speed of the granulator, the outflow flow rate, the viscosity temperature characteristic, the granulator structure, the granulator size, the granulator surface roughness, and the granulator edge wind speed and angle;
starting a normal granulation process after the relationships between the particle size of granulated slag and the rotation speed of the granulator, the outflow flow rate, the viscosity temperature characteristic, the granulator structure, the granulator size, the granulator surface roughness, and the granulator edge wind speed and angle are obtained;
if the particle size of the granulated slag obtained according to the relationship of the particle size is larger than a set interval during the normal granulation process, increasing a granule speed of the granulator to return to the set interval; if the particle size of the granulated slag is smaller than the set interval, decreasing the granule speed of the granulator to return to the set interval.
Preferably, a temperature control means of the temperature control unit comprises: providing a temperature control program on the cache device, providing a heat supplement solution on the cache device, providing the temperature control program on the cache device and adding a heat supplement solution.
Preferably, if the viscosity-temperature characteristics of the slag known are not capable of meeting the requirements for controlling the particle size of the granulated slag, the particle size is controlled by adjusting the alkalinity of the slag to adjust the viscosity-temperature characteristics of the slag.
Preferably, the dry centrifugal granulation system for the liquid slag comprises: a granulator (219), a granulator fixing device (232) and a granulator driving device; wherein the granulator is fixed on the granulator fixing device (232); and the granulator fixing device is provided with an air flow channel (233), the granulator fixture contacts a bottom of the granulator to provide an expanded heat receiving surface (234); the top of the granulator fixture has a plurality of first tuyeres (236), and the outlet angle of the top first tuyere and the edge of the granulator The dip angle intersects to externally crush the liquid film or liquid filament formed during the granulation process; the granulator fixing device (232) has a plurality of second tuyères (235) on the side, and the second tuyere and the edge of the granulator are inclined The angles are parallel or intersected for cooling droplets formed by liquid filament breakage during granulation; the first tuyere and the second tuyere are in communication with the gas flow passage (233); the granulator drive is used to drive the granulator to rotate.
Preferably, the liquid slag dry centrifugal granulation system further includes a granulator drive device and a shaft cooling air channel;
wherein the granulator driving device comprises a motor (209) and a rotating shaft (223); the output shaft of the motor (209) is fixedly connected with the lower end of the rotating shaft (223); the upper end of the rotating shaft is fixedly connected with the bottom of the granulator fixing device (232); a plurality of temperature resistant blades (224) are disposed on the rotating shaft;
the shaft cooling air duct comprises a motor sealing cover (210), an inner tube sleeve (217), a shaft sleeve (222) and a rotating shaft (223); the sealing cover (210) surrounds the outer circumference of the motor (209), and the inner tube of the air duct (217) and the shaft sleeve (222) is sleeved on the outer circumference of the rotating shaft (223); the inner ring of the temperature resistant thrust bearing (212) and the temperature resistant positioning bearing (221) are fixed on the rotating shaft (223), and the outer ring is fixed at The inner wall of the inner sleeve (217); the shaft sleeve (222) is fixed between the outer ring of the temperature-resistant bearing at the top thereof and the outer ring of the temperature-resistant bearing at the lower portion thereof, and the temperature-resistant blade (224) is surrounded therein; Both the temperature thrust bearing (212) and the temperature resistant positioning bearing (221) are provided with an air flow passage (218);
the sealing cover (210) is fixedly connected with the inner tube sleeve (217) and communicated through the vent (226);
an outer sleeve (216) is arranged on the outer circumference of the inner sleeve (217) of the air duct, and an annular cooling air duct is formed between the inner sleeve (217) of the air duct and the outer sleeve (216) of the air duct, and the annular cooling duct is arranged at the top of the annular shape; there are a number of hoods (220); the bottom of the outer sleeve of the duct is provided with an annular cooling duct air inlet (225).
Preferably, the shaft cooling air enters from the sealing hood tuy, and after cooling the rotating shaft inside the shaft sleeve, most of the air flow passages entering the granulator fixing device, and a plurality of first air outlets uniformly distributed from the top and the side wall of the granulator fixing device And the second tuyere enters the granulation chamber, and a small portion enters the granulation chamber from a narrow gap between the granulator fixture and the inner sleeve of the duct.
Preferably, the air outlet of the hood is lower than the air outlet of the first air outlet and the second air outlet
Preferably, the bottom of the rotating shaft (223) is provided with a temperature-resistant thrust bearing (212), and one or more temperature-resistant positioning bearings (221) are arranged in the middle and the upper part of the rotating shaft, wherein the uppermost positioning bearing should be as close as possible to the bottom of the granulator fixing device.
Preferably, there are three ways to generate shaft cooling air:
(1) in the first mode, the cooling air is generated by the fan, entering from the sealing hood tuyere (227), and most of the airflow passage (233) passing through the granulator fixing device flows out, and a small portion is between the fixing device and the inner tube sleeve (217). a small gap flows out;
(2) in the second mode, the temperature-resistant blade (224) on the rotating shaft (223) generates cooling air according to the high-speed rotation of the rotating shaft, and most of the airflow passage (233) flows out through the granulator fixing device (232), and a small portion is fixed from the fixing device. a narrow gap between the inner sleeve (217) of the air duct;
(3) in the third mode, the fan air outlet and the high temperature rotating blade of the temperature resistant blade cooperate as the shaft cooling wind to cool the shaft cooling air duct and the rotating shaft.
Compared with the prior art, the present invention has the following beneficial effects.
(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.
(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.
(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.
Further description of the present invention is illustrated combining with the accompanying drawings and the preferred embodiments of the present invention.
209—motor; 210—sealing cover; 211—coupling; 216—duct outer sleeve; 217—duct inner sleeve; 219—granulator; 220—hood; 222—shaft sleeve; 223—rotation shaft; 224—temperature resistant blade; 225—annular air vent; 226—blow vent; 227—sealing cover air vent; 232—granulator fixture; 233—airflow runner; 234—expanded heating surface; 235—second air vent; 236—first air vent.
Referring to
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 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;
the method for controlling a particle size of dry centrifugal granulated slag from liquid slag specifically comprises steps of:
step (1) through the temperature control unit, the flow control unit and the granulator control unit, controlling a temperature and a flow rate of a liquid slag falling into the granulator, and ensuring that the granulator and the slag tube are centered and smooth without shaking; then commissioning; through a process test, adjusting a rotation speed of the granulator, an outflow flow rate, a viscosity temperature characteristic, a granulator structure, a granulator size, a granulator surface roughness, a granulator edge wind speed and angle, so as to obtain relationships between a particle size of the granulated slag and the rotation speed of the granulator, the outflow flow rate, the viscosity temperature characteristic, the granulator structure, the granulator size, the granulator surface roughness, and the granulator edge wind speed and angle;
starting a normal granulation process after the relationships between the particle size of granulated slag and the rotation speed of the granulator, the outflow flow rate, the viscosity temperature characteristic, the granulator structure, the granulator size, the granulator surface roughness, and the granulator edge wind speed and angle are obtained;
if the particle size of the granulated slag obtained according to the relationship of the particle size is larger than a set interval during the normal granulation process, increasing a granule speed of the granulator to return to the set interval; if the particle size of the granulated slag is smaller than the set interval, decreasing the granule speed of the granulator to return to the set interval.
A temperature control means of the temperature control unit comprises: providing a temperature control program on the cache device, providing a heat supplement solution on the cache device, providing the temperature control program on the cache device and adding a heat supplement solution.
If the viscosity-temperature characteristics of the slag known are not capable of meeting the requirements for controlling the particle size of the granulated slag, the particle size is controlled by adjusting the alkalinity of the slag to adjust the viscosity-temperature characteristics of the slag.
The liquid slag dry centrifugal granulation system comprises: a granulator 219, a granulator fixing device 232 and a granulator driving device; the granulator 219 has a disk shape or a cup shape, and the edge inclination angle is 30° to 60°, the center A flow guiding cone is provided; the granulator 219 is fixed on the granulator fixing device 232; the granulator fixing device 232 is internally provided with an air flow passage 233; and the granulator fixing device 232 is connected to the bottom of the granulator 219 to provide extended heat. The surface 234, such as an annular rib, can better cool the granulator fixture; the granulator fixture 232 has a plurality of first tuyères 236 at the top, and the outlet angle of the first tuyere and the edge of the granulator When intersected, the liquid film or liquid filament formed during the granulation process can be externally broken to enhance the granulation effect; the granulator fixing device 232 is provided with a plurality of second tuyères 235 on the side, and the second tuyere and the edge of the granulator are inclined Parallel or cross, the droplets formed by the liquid filament breakage during granulation can be cooled to increase the glass transition rate. The first tuyere 236 and the second tuyere 235 are in communication with the air flow passage 233.
The granulator driving device includes a motor 209, a sealing cover 210, a rotating shaft 223, a shaft sleeve 222, an inner tube sleeve 217, an outer tube sleeve 216, a hood 220, and the like. The motor 209 and the rotating shaft 223 are coupled by a coupling 211; the rotating shaft is provided with a plurality of temperature-resistant blades 224; the bottom of the rotating shaft 223 is provided with a temperature-resistant thrust bearing 212, and one or more temperature-resistant positioning bearings 221 are provided at the middle and the upper portion of the rotating shaft. The uppermost positioning bearing should be as close as possible to the bottom of the granulator fixing device 232. On the one hand, the rotating shaft of the high-speed rotating shaft can be improved due to the inaccurate mechanical structure, thereby affecting the granulation effect, and on the other hand, the life of the device can be prolonged.
The shaft cooling air duct includes a motor seal cover 210, an air duct inner sleeve 217, a shaft sleeve 222, and a rotating shaft 223. The sealing cover 210 surrounds the outer circumference of the motor 209, and the inner sleeve 217 and the shaft sleeve 222 are sleeved on the outer circumference of the rotating shaft 223; the inner rings of the temperature-resistant thrust bearing 212 and the temperature-resistant positioning bearing 221 are fixed on the rotating shaft 223, and the outer ring Fixed to the inner wall of the inner sleeve 217 of the air duct; the shaft sleeve 222 is fixed between the outer ring of the upper temperature-resistant bearing and the outer ring of the lower temperature-resistant bearing thereof, and the temperature-resistant blade 224 is surrounded therein; the temperature-resistant thrust bearing 212 and The air temperature locating bearing 221 is provided with a supply air flow path 218. A granulator fixing device 232 is fixed to the top of the rotating shaft 223.
The sealing cover 210 is fixedly connected to the inner tube sleeve 217, communicates through the vent 226, and the shaft cooling air enters from the sealing cover tuyere 227. After cooling the rotating shaft 223 through the inside of the shaft sleeve 222, most of it enters the granulator fixing device 232. The air flow passage 233 enters the granulation chamber from the plurality of first tuyere 236 and the second tuyere 235 which are annularly distributed from the top and the side wall of the granulator fixing device 232, and a small portion from the granulator fixing device 232 and the inner tube sleeve 217 A narrow gap enters the granulation bin. An outer tube sleeve 216 is disposed on the outer circumference of the inner tube sleeve 217, and an annular cooling air passage is formed between the inner tube sleeve 217 and the outer tube sleeve 216. The top of the annular cooling air channel is annularly arranged with a plurality of hoods 220, and the hood 220 The air outlet is lower than the air outlets of the first tuyere 236 and the second tuyere 235. An annular cooling air duct air inlet 225 is opened at the bottom of the outer tube sleeve 216.
In the present invention, the granulator fixing device 232 is composed of two parts, left and right, and is fixed by a pin and a hoop. When the granulator 219 is damaged, the pin is removed, the granulator 219 and the granulator fixing device 232 can be removed, the pin and the hoop can be removed, and the left and right parts of the granulator fixing device 232 can be disassembled and removed. The granulator 219 can be removed after the annular clamp. When the granulator 219 is cracked, the cracked granulator 219 is not smashed due to the presence of the granulator base and the fixture, and the liquid slag does not drip directly onto the transmission and the motor 209. Ensure system safety before downtime. At the same time, it is only necessary to replace the granulator 219, which reduces the cost of replacing the entire granulator by the general granulator 219 due to damage. The granulator fixing device 232 is internally provided with a streamlined flow passage 233; at the same time, the gap between the bottom side of the granulator base and the inner sleeve 217 of the air duct is small, so that most of the wind sent from the lower portion of the granulator base can enter. To the streamlined flow passage 233, the granulator fixture 232 is cooled while facilitating the blowing of wind from the granulator base to the edge of the granulator 219 to enhance granulation.
In the present invention, the rotating shaft 223 and the granulator fixing device 232 are connected by a hollow flange, and the hollow flange has a section of air heat insulating layer between the granulator base and the rotating shaft 223 to block the granulator 219 and the rotating shaft 223. The heat transfer between the granulator base is not transmitted to the rotating shaft 223, so that the granulator 219 can be safely and stably operated, and the granulation effect can be better realized.
There are three ways to generate the shaft cooling air: mode one, the cooling air is generated by the fan, entering from the sealing hood tuyere 227, most of the annular air duct passing through the granulator fixing device enters the granulation chamber, and a small part is from the fixing device and the air duct inner sleeve. The narrow gap between the cylinders 217 enters the granulation chamber; in the second embodiment, the first and second or multi-stage small temperature-resistant blades 224 are arranged on the rotating shaft 223, and the cooling wind is generated by the high-speed rotation of the rotating shaft, and most of them are fixed by the granulator. The annular duct of unit 232 enters the granulation chamber and a small portion enters the granulation chamber from a narrow gap between the fixture and the inner sleeve 217 of the duct. The rotating shaft 223 is provided with one-stage, two-stage or multi-stage small temperature-resistant blades 224. When the rotating shaft 223 rotates at a high speed, on the one hand, the flow power of the shaft cooling air passage is generated, and the acceleration shaft cooling air shaft and the granulator fixing device are generated. Cooling, on the other hand, the temperature-resistant blade 224 can also be used as a rib structure to enhance the overall heat dissipation of the rotating shaft 223; in the third mode, the wind blower and the small temperature-resistant blade are combined with the high-speed rotating wind as the shaft cooling wind, and the shaft cooling wind Cooling of components such as the track and the shaft.
One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.
It will thus be seen that the objects of the present invention have been fully and effectively accomplished. Its embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201810159868.4 | Feb 2018 | CN | national |
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.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2018/096520 | 7/20/2018 | WO | 00 |
