CN104180634B - A kind of rotary kiln drying machine concentrate drying system and concentrate drying method thereof - Google Patents

Abstract

The invention provides a concentrate drying system of a rotary kiln dryer and a concentrate drying method thereof, the system includes a hot blast furnace, a rotary kiln dryer, and the rotary kiln dryer includes a kiln shell, a kiln head box and a kiln tail box , the system also includes a lifting plate and a high-temperature flue gas circulation loop, and the lifting plate is uniformly fixed on the kiln shell and connected to the hot blast stove; the high-temperature flue gas circulation loop includes a cyclone dust collector, a moisture absorber, One end of the primary cyclone dust collector is connected to the kiln tail box, and the other end is connected to the moisture absorber; one end of the circulation fan is connected to the moisture absorber, and the other end is connected to the hot blast stove. The equipment in the high-temperature flue gas circulation loop is connected through the return hot air pipeline. The concentrated ore drying system of the rotary kiln dryer in the present invention can effectively prolong the service life of the lifting plate, strengthen the lifting effect of the lifting plate, and reduce energy consumption while increasing the operating rate.

Description

A concentrate drying system of a rotary kiln dryer and a concentrate drying method thereof

technical field

The invention relates to the technical field of rotary kiln structure, in particular to a concentrate drying system of a rotary kiln dryer and a concentrate drying method thereof.

Background technique

Oxidation pellets are one of the important methods of fine ore agglomeration. The ore concentrate powder is first dried in a drying kiln, and then rolled to a suitable strength, and then an appropriate amount of water and binder are added to the pelletizer to make green balls with uniform viscosity and sufficient strength. After the green balls are preheated, they are roasted in an oxidizing atmosphere, so that the green balls are agglomerated and chemically reacted to produce pellets. The current process flow chart of the pellets is shown in Figure 1. The oxidation pellet process is especially suitable for the treatment of fine ore concentrates. The produced pellets have good cold strength, reducibility and particle size. In the iron and steel industry, pellets are an important blast furnace charge, which can be combined with sinter to form a better charge structure, and are widely used in major iron and steel enterprises.

In the production of oxidized pellets, the first step is to dry the concentrate powder. The effect of this step will affect the subsequent steps of the process, especially the effect of roller milling and pelletizing. Excessive moisture will cause the concentrate powder to adhere to the roller mill and cause material jams, and will affect the moisture content inside the pellets. The front of the grate is broken in advance, which has a negative impact on the output and operating rate of the entire production line. At present, the concentrate dryers on the market can be divided into belt dryers, disc dryers and cylinder dryers according to their structures. The advantages of large size, strong material adaptability, low operating cost and light environmental pollution are widely used by everyone. This patent also elaborates on this type of structure dryer.

In the prior art, the process configuration diagram of the rotary kiln drying system is shown in FIG. 2 . The system consists of a hot blast stove 1, a rotary kiln dryer 2 (including a kiln head box 22 and a kiln tail box 21), a primary cyclone dust collector 3, a secondary electric dust collector 4 and a chimney 5. During production, the fine ore powder enters the rotary kiln dryer 2 from the kiln tail box 21 , moves against the hot air, and is finally discharged from the kiln head box 22 . The hot air generated by the hot blast stove 1 enters the rotary kiln dryer 2 from the kiln head box 22, moves in the opposite direction with the material flow, and enters the primary cyclone dust collector 3 from the kiln tail box 21, where the air flow is carried from the rotary kiln dryer 2 After gravitational settlement, the large particles of dust enter the secondary electrostatic precipitator 4, and then absorb the small particles of dust, and finally discharge them into the atmosphere through the chimney 5.

In the prior art, the circumferential sectional view of the rotary kiln dryer is shown in FIG. 3 , and the A-A sectional view of FIG. 3 is shown in FIG. 4 . Along the circumference of the rotary kiln dryer, the lifting plate 8 (the single structure of the lifting plate 8 is a 7-frame shape) is evenly welded on the drying kiln shell 7 in a circle, and the inner surface of the drying kiln shell 7 is poured with drying Kiln refractory lining 6, after the wet material is put into the rotary kiln dryer 2 through the kiln tail box 21, the material is evenly distributed and dispersed in the rotary kiln dryer 2 under the turning of the lifting plate 8 uniformly distributed in the kiln , and fully contact with the co-current (counter-current) hot air, so as to be heated and dried. Under the action of the lifting plate with an inclined angle (about 3 degrees) and the hot air flow, the material can be regulatedly moved to the rotary kiln dryer 2 The other section is discharged through the kiln head box 22. By adjusting the rotation speed of the rotary kiln dryer 2 to speed up (slow down) the forward speed of the material in the kiln, thereby adjusting the length of time the material is in contact with the hot air.

The existing concentrate rotary kiln dryer has the following three defects in the drying process:

1. The effect of the lifting plate is poor: during the drying process, the concentrate enters from the kiln tail of the rotary kiln dryer, is scattered and raised by the lifting plate in the kiln, and is in reverse contact with the hot air at the same time, and finally discharged from the kiln head . Due to the small particle size and high humidity of the dried concentrate, it is easy to adhere to the lifting plate during the drying process. If it is not cleaned for a long time, nodules will form, which will not only increase the workload of the entire kiln, but also It will lead to poor dispersion of the concentrate, which will lead to incomplete drying and low heat transfer efficiency.

2. The service life of the lifting plate is short: the lifting plate in the drying kiln is often worn, broken and broken due to its extremely harsh working environment (high temperature and dust), and the life cycle of each lifting plate is different. , There are dozens of lifting plates in a drying kiln. It is obviously unacceptable to reduce the operating rate of the entire production line if frequent shutdowns are caused by the replacement of lifting plates.

3. High energy consumption: the existing concentrate drying kiln generally has the problem of high energy consumption. After analysis, it is found that there are two reasons for this problem: one is that the lifting plate is easy to form nodules, which leads to the lifting The material effect is poor, the contact between the concentrate and the hot air is not sufficient, and the contact specific surface area is not large, most of the hot air does not play the role of drying the concentrate but is directly discharged from the kiln tail, thereby reducing the heat exchange efficiency and increasing the energy consumption value The second is that the hot air discharged from the rotary kiln dryer does not take measures to recycle it, but is directly emptied, resulting in a great waste of energy.

4. Cause environmental pollution: The existing concentrate drying system directly discharges the hot air after dust removal to the atmosphere through the chimney, and the air flow contains harmful components such as unburned CO, NO and C, which pollutes the environment.

Therefore, it is of great significance to develop a rotary kiln dryer concentrate drying system with good drying effect, low energy consumption value, and energy saving of the entire production line.

Contents of the invention

(1) Technical problems to be solved

In order to solve the above problems, the object of the present invention is to provide an energy-saving and high-efficiency rotary kiln dryer concentrate drying system and a concentrate drying method.

(2) Technical solutions

The purpose of the present invention is to provide a rotary kiln dryer concentrate drying system, the system includes a hot blast stove, a rotary kiln dryer, the rotary kiln dryer includes a kiln shell, a kiln head box and a kiln tail box, the system It also includes a lifting plate and a high-temperature flue gas circulation loop, the lifting plate is uniformly fixed on the kiln shell, and is connected with the hot blast stove; the high-temperature flue gas circulation loop includes a cyclone dust collector, a moisture absorber, a heat recovery One end of the primary cyclone dust collector is connected to the kiln tail box, and the other end is connected to the moisture absorber; one end of the circulation fan is connected to the moisture absorber, and the other end is connected to the hot blast stove. The equipment in the air circulation circuit is connected through the return hot air pipeline.

In the actual working conditions of the existing technology, after the hot air entering from the kiln head of the rotary kiln dryer exchanges heat with the material in the kiln, the temperature of the air discharged from the kiln tail is still 200-300°C, and this part of the hot air is not recycled. , but directly discharged into the atmosphere after dust removal. Compared with the prior art, the rotary kiln dryer concentrate drying system of the present invention cancels the secondary electrostatic precipitator and exhaust chimney in the traditional system of the prior art, and adds a moisture absorber, return hot air pipeline and circulation The fan makes the high-temperature flue gas no longer be discharged outside, but returns to the hot blast stove after dust removal and dehumidification, and continues to be recycled as combustion-supporting gas together with the fresh air supplied by the fan.

The concentrated ore drying system of the rotary kiln dryer of the present invention cancels the chimney and the secondary electrostatic precipitator, because the present invention recycles the original exhaust gas, so the chimney is not needed. The hot blast stove where the circulating air finally arrives does not pay much attention to the small particle dust content in the air flow, so the secondary electrostatic precipitator can be cancelled. In addition, the concentrate fine powder and coal powder carried away by the flue gas in a single cycle are transported to the next cycle for utilization, achieving the effect of energy saving.

Through the calculation of air flow balance and heat balance, when the fresh air volume entering the hot blast stove: circulating air volume = 3:1 (taking 1.2 million tons/year oxidation pellet line as an example, the total air volume at the outlet of the hot blast stove is 12000m ³ , then enter The fresh air of the hot blast stove is 9000m ³ , and the circulating air is 3000m ³ ). The total energy consumption of the system is the lowest and the effect is the best.

Preferably, the lifting plate is a high-pressure air cushion type lifting plate, and the high-pressure air cushion type lifting plate is evenly fixed on the drying kiln shell along the circumference of the rotary kiln dryer (also called drying kiln), and the drying The inner wall of the kiln shell is cast with a dry kiln refractory lining. The high-pressure air cushion type lifting plate is a hollow structure, which is composed of a steel shell of the lifting plate and a hollow air chamber arranged inside the lifting plate. The hollow air cavity The chamber is adjacent to the inner surface of the steel shell of the lifting plate, and the steel shell of the lifting plate is provided with blowing holes, and the blowing holes are arranged above the burial height of the refractory lining.

Viewed from the circumferential direction of the drying kiln, the buried height of the refractory lining is the highest end of the lifting plate buried in the refractory lining. The lifting plate is welded on the inner surface of the kiln shell of the drying kiln, and the refractory lining (constructed by refractory material cast on site) is also built on the inner surface of the kiln shell, so that the lifting plate will inevitably be buried in the drying process. It is a part of the circumferential length of the kiln, and the part of the lifting plate that exposes the refractory lining is the part that is actually used in production. Therefore, the blast holes described in the present invention must be arranged above the burial height of the refractory lining to ensure its normal operation.

Preferably, in the main viewing direction of the lifting plate, the height of the circle center of the lowest row of blast holes is 20 mm or more higher than the burial height of the refractory lining. Under the premise of not affecting the production, the height of the center of the lowest row of blast holes should be as high as possible.

Preferably, the concentrated ore drying system of the rotary kiln dryer of the present invention also includes a kiln wall air supply system, and the high-pressure air cushion type lifting plate is connected to the hot blast stove through the kiln wall air supply system, and the kiln wall air supply system includes Air supply pipeline, connecting pipe, annular air inlet main pipe and air inlet branch pipe, one end of the connecting pipe is connected to the hot blast stove through the air supply pipeline, and the other end is connected to the annular air inlet main pipe, and the air inlet branch pipe is along the kiln circumferential direction The direction is evenly distributed in a circle with the center of the kiln as the center. One end of the air inlet branch pipe is connected to the annular air inlet main pipe, and the other end is inserted into the kiln and connected to the high-pressure air cushion type lifting plate at the corresponding position.

Among them, the high-pressure air cushion lifting plate is evenly welded on the drying kiln shell in a circle along the circumference of the rotary kiln dryer, and the inner surface of the drying kiln shell is poured with a drying kiln refractory lining. The type lifting plate is connected with the air inlet branch pipe at the corresponding position.

Wherein, one end of the connecting pipe is connected to the air supply pipeline through the flange, and then connected to the hot blast stove through the air supply pipeline, and the other end is connected to the annular air inlet main pipe.

Wherein, the distribution angle and quantity of the air inlet branch pipes are determined according to the distribution of the lifting plates in the kiln.

According to the different positions on the rotary kiln dryer, the kiln wall air supply system can be divided into the head kiln wall air supply system, the middle kiln wall air supply system and the tail kiln wall air supply system along the axial direction of the rotary kiln dryer. The wind system has three parts. When the concentrate enters the kiln from the kiln tail, its humidity is the highest, and it is most likely to form nodules on the lifting plate, so the air volume supplied to this part should be the largest, followed by the air volume in the middle, and the smallest air volume in the head. The specific air volume ratio can be determined according to the site. Adjust the actual situation.

Among them, the hot air from the hot blast stove enters the kiln wall air supply system along the air supply pipeline. The high-temperature and high-pressure air (hot air) in the air inlet branch enters from the inner hollow air chamber of the high-pressure air cushion type lifting plate, and is sprayed into the kiln through the air spray holes arranged on the steel shell of the lifting plate. A layer of air cushion is formed on the outer surface, which plays the role of protecting the lifting plate and strengthening the effect of breaking up materials, which changes the way of hot air entering the kiln head in the prior art.

Unless otherwise specified, the connection of each structure of the concentrate drying system of the rotary kiln dryer of the present invention is connected through the air supply pipeline, and a plurality of release points are set on the air supply pipeline to ensure the air flow balance in the air supply pipeline .

Further preferably, the concentrated ore drying system of the rotary kiln dryer of the present invention also includes a flow detection and control device, and a flow control valve and a flow detection device are arranged on the air supply pipeline, which can be adjusted according to the detected real-time flow when the system is running. Control the opening of the valve to ensure a reasonable distribution of the air flow value.

During the construction of the rotary kiln dryer (also known as drying kiln) and the lifting plate, the kiln shell of the drying kiln must have holes at the corresponding positions where the high-pressure air cushion type lifting plate is installed, so as to connect the air inlet branch pipe and the lifting plate The hollow air chambers are connected together, so that the hot air can enter the inside of the lifting plate smoothly. At the same time, the refractory lining of the drying kiln must be constructed using the on-site formwork method of ramming materials. The construction starts from a certain place. After a section is completed, turn a certain angle to continue the construction of the next section of refractory lining, and repeat in turn until the entire circle of refractory lining is completed. The construction of the lining to protect the air blow holes of the lifting plate from entering the refractory powder.

The invention also provides a concentrate drying method based on the concentrate drying system of the rotary kiln dryer.

When the concentrated ore drying system of the rotary kiln dryer of the present invention is used for production, the hot air generated in the hot blast furnace enters the kiln wall air supply system along the air supply pipeline, and a flow control valve and a flow detection device are arranged on the air supply pipeline. Adjust the opening of the control valve according to the detected real-time flow to ensure a reasonable distribution of the airflow value in each place. The hot air first enters the connecting pipe, then enters the annular air inlet main pipe, then enters the air inlet branch pipe and the hollow air chamber inside the high-pressure air cushion lifting plate, and finally sprays into the kiln from the air injection holes arranged on the steel shell of the lifting plate. Inside. Affected by the negative pressure of the circulating fan, the hot air in the kiln will leave the rotary kiln dryer from the kiln tail box, and then pass through the cyclone dust collector, moisture absorber and circulating fan along the return hot air pipeline, and finally return to the hot air In the furnace, a wind circulation process is completed. At the same time, the direction of material flow in the rotary kiln dryer is to enter the rotary kiln dryer from the kiln tail box, contact with the wind flow in the kiln in reverse, and finally discharge from the kiln head box.

(3) Beneficial effects

The concentrated ore drying system of the rotary kiln dryer of the present invention has the following advantages:

(1) The high-pressure air cushion type lifting plate of the concentrate drying system of the rotary kiln dryer of the present invention has a good use effect: because the lifting plate is densely covered with blowing holes for spraying high-pressure air, even if the concentrate powder is in the drying process Adhesion to the lifting plate can also be removed immediately because it is blown off by the high-pressure wind, eliminating the hidden danger of nodules formed due to long-term failure to clean up, thereby ensuring the effect of the lifting plate breaking up the concentrate , so that the drying is thorough and the heat exchange efficiency is high.

(2) The high-pressure air cushion type lifting plate of the concentrate drying system of the rotary kiln dryer of the present invention has a long service life: because the high-pressure air ejected from the air blowing hole forms a layer of air cushion on the surface of the lifting plate, it effectively protects the lifting plate. The material plate reduces the wear, fracture and breakage caused by direct contact with the concentrate powder during actual production, thus greatly prolonging the service life of the lifting plate and improving the operating rate of the entire drying kiln system .

(3) Energy consumption can be reduced: the concentrate drying system of the rotary kiln dryer of the present invention circulates the hot air discharged from the rotary kiln dryer to the hot blast stove for recycling after dedusting and dehumidification. Direct emptying saves energy and reduces energy consumption values. Taking the oxidized pellet production line of 1.2 million tons per year as an example, the amount of hot air discharged outside the drying kiln per hour is 12,000m ³ . Calculated according to the air temperature of 200°C, the enthalpy value of the exhausted air per hour is 816,000 kcal (not shown Including the chemical heat contained in the unburned CO, C and other substances in the flue gas), calculated according to the utilization efficiency of 70%, the new scheme can save about 571,200 kcal of energy per hour for the system, equivalent to about 85 kg of bituminous coal.

(4) Environmental pollution can be reduced: in the prior art, the hot air after dedusting is directly discharged into the atmosphere through the chimney, and the air flow contains harmful components such as unburned CO, NO, and C, which pollute the environment. In contrast, the present invention recycles wind flow, avoids environmental pollution by exhaust gas, and effectively protects the atmospheric environment.

(5) Using the concentrated ore drying system of the rotary kiln dryer of the present invention can effectively prolong the service life of the lifting plate, strengthen the lifting effect of the lifting plate, and reduce energy consumption while increasing the operating rate. Compared with the existing drying system, it is more energy-saving, economical, reliable and environmentally friendly, and it can be predicted that it has great development potential in the future market.

Description of drawings

Fig. 1 is existing pelletizing process flow chart;

Fig. 2 is the technological configuration figure of prior art rotary kiln drying system;

Fig. 3 is the circumferential sectional view of prior art rotary kiln dryer;

Fig. 4 is A-A sectional view of Fig. 3;

Fig. 5 is a process configuration diagram of the concentrate drying system of the rotary kiln dryer according to the embodiment of the present invention;

Fig. 6 is the front view of the rotary kiln dryer in the embodiment of the present invention;

Fig. 7 is the B direction view of Fig. 6;

Fig. 8 is a C-C sectional view of Fig. 6;

Fig. 9 is an enlarged view at D of Fig. 8;

Figure 10 is a schematic diagram of the burial height of the refractory lining in the embodiment of the present invention;

Figure 11 is a circumferential sectional view of a rotary kiln dryer without a refractory lining;

Fig. 12 is a circumferential sectional view of the rotary kiln dryer after the first section of refractory lining has been constructed;

Figure 13 is a circumferential cross-sectional view of the rotary kiln dryer after the second stage of refractory lining has been constructed;

In the figure: 1 is a hot blast stove; 2 is a rotary kiln dryer; 21 is a kiln tail box; 22 is a kiln head box; 3 is a cyclone dust collector; 4 is a secondary electric dust collector; 5 is a chimney; 6 is a drying kiln Refractory lining; 7 is the kiln shell of the drying kiln; 8 is the lifting plate; 81 is the steel shell of the lifting plate; 82 is the hollow air chamber; 83 is the blowing hole; 9 is the connecting pipe; 12 is the moisture absorber; 13 is the return hot air pipeline; 14 is the circulation fan; 15 is the flow detection device; 16 is the flow control valve; 17 is the air supply pipeline; 18 is the refractory lining burial Height; 61 is the first section of refractory lining; 62 is the second section of refractory lining.

detailed description

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", " The orientations or positional relationships indicated by "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying Describes, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and operate in a specific orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

In addition, in the description of the present invention, unless otherwise specified, the meanings of "plurality", "multiple roots" and "multiple groups" are two or more.

As shown in Figures 5-8, the rotary kiln dryer concentrate drying system of this embodiment includes a hot blast furnace 1 and a rotary kiln dryer 2, and the rotary kiln dryer 2 includes a kiln shell 7, a kiln head box 22 and a kiln tail box 21, the system also includes a high-pressure air cushion type lifting plate 8 and a high-temperature flue gas circulation loop, and the high-pressure air cushion type lifting plate 8 is evenly fixed on the kiln shell 7 and connected to the hot blast stove 1; The high-temperature flue gas circulation loop includes a primary cyclone dust collector 3, a moisture absorber 12, a return hot air pipeline 13, and a circulating fan 14. One end of the primary cyclone dust collector 3 is connected to the kiln tail box 21, and the other end is connected to the moisture absorber. 12; one end of the circulating fan 14 is connected to the moisture absorber 12, and the other end is connected to the hot blast stove 1, and the equipment in the high-temperature flue gas circulation loop is connected through the return hot air pipeline 13.

In the actual working conditions of the existing technology, after the hot air entering from the kiln head of the rotary kiln dryer exchanges heat with the material in the kiln, the temperature of the air discharged from the kiln tail is still 200°C, and this part of the hot air has not been recycled. It is directly discharged into the atmosphere after dust removal. Compared with the prior art, the concentrate drying system of the rotary kiln dryer in this embodiment cancels the secondary electrostatic precipitator and exhaust chimney in the traditional system of the prior art, and adds a moisture absorber 12 and a return hot air pipeline 13 and the circulation fan 14, so that the high-temperature flue gas is no longer discharged, but returns to the hot blast stove 1 after dedusting and dehumidification and continues to be recycled as the combustion-supporting gas together with the fresh air supplied by the blower fan.

The concentrate drying system of the rotary kiln dryer in this embodiment cancels the chimney and the secondary electrostatic precipitator, because the embodiment of the present invention recycles the original exhaust gas, so the chimney is not needed. The hot blast stove where the circulating air finally arrives does not pay much attention to the small particle dust content in the air flow, so the secondary electrostatic precipitator can be cancelled. In addition, the concentrate fine powder and coal powder carried away by the flue gas in a single cycle are transported to the next cycle for utilization, achieving the effect of energy saving.

Through the calculation of air flow balance and heat balance, when the fresh air volume entering the hot blast stove: circulating air volume = 3:1 (taking 1.2 million tons/year oxidation pellet line as an example, the total air volume at the outlet of the hot blast stove is 12000m ³ , then enter The fresh air of the hot blast stove is 9000m ³ , and the circulating air is 3000m ³ ). The total energy consumption of the system is the lowest and the effect is the best.

As shown in Fig. 8-9, the high-pressure air cushion type lifting plate 8 is evenly fixed on the kiln shell 7 along the circumference of the rotary kiln dryer, and the inner wall of the shell 7 of the kiln is poured with a refractory lining 6 of the kiln. The high-pressure air pad type lifting plate 8 is a hollow structure, consisting of a steel shell 81 of the lifting plate and a hollow air chamber 82 arranged inside the lifting plate 8, and the hollow air chamber 82 is adjacent to the steel shell of the lifting plate On the inner surface of 81, the steel shell 81 of the lifting plate is provided with blowing holes 83, and the blowing holes 83 are arranged above the buried height of the refractory lining 18.

As shown in FIG. 10 , viewed from the circumferential direction of the drying kiln, the buried height 18 of the refractory lining is the highest end of the lifting plate 8 buried in the refractory lining 6 . The lifting plate 8 is welded on the inner surface of the kiln shell 7 of the drying kiln, and the refractory lining 6 (constructed by on-site pouring of refractory materials) is also built on the inner surface of the kiln shell 7, which will inevitably bury the lifting A part of the material plate 8 on the circumferential length of the drying kiln, and the part of the lifting plate 8 that exposes the refractory lining 6 is the part that is actually used in production. Therefore, the blast holes 83 in the present invention must be arranged above the burial height 18 of the refractory lining to ensure its normal operation.

Preferably, in the main view direction of the lifting plate 8 , the center height of the lowest row of blast holes 83 is higher than the buried height 18 of the refractory lining by more than 20mm. Under the premise of not affecting production, the height of the center of circle of the lowest row of blast holes 83 should be as high as possible.

As shown in Figures 5-8, the concentrate drying system of the rotary kiln dryer in the embodiment of the present invention also includes a kiln wall air supply system, and the high-pressure air cushion type lifting plate 8 is connected to the hot blast stove 1 through the kiln wall air supply system , the kiln wall air supply system includes an air supply pipeline 17, an air supply pipe 9, an annular air inlet main pipe 11 and an air inlet branch pipe 10, one end of the connecting pipe 9 is connected to the hot blast stove 1 through the air supply pipeline 17, and the other One end is connected with the annular air inlet main pipe 11, and the air inlet branch pipe 10 is uniformly distributed in a ring along the kiln circumferential direction with the kiln center as the center. One end of the air inlet branch pipe 10 is connected with the annular air inlet main pipe 11, and the other end is inserted into the kiln , connected with the high-pressure air cushion type lifting plate 8 at the corresponding position.

Among them, the high-pressure air cushion type lifting plate 8 is evenly welded on the drying kiln shell 7 along the 2 circumferences of the rotary kiln dryer, and the inner surface of the drying kiln shell 7 is poured with a drying kiln refractory lining 6, The high-pressure air cushion type lifting plate 8 is connected to the air inlet branch pipe 10 at the corresponding position.

Wherein, one end of the connecting pipe 9 is connected to the air supply pipeline 17 through the flange, and then connected to the hot blast stove 1 through the air supply pipeline 17, and the other end is connected to the annular air inlet main pipe 11.

Wherein, the distribution angle and quantity of the air inlet branch pipes 10 are determined according to the distribution of the lifting plates 8 in the kiln.

According to the different positions on the rotary kiln dryer, the kiln wall air supply system can be divided into the head kiln wall air supply system, the middle kiln wall air supply system and the tail kiln wall air supply system along the axial direction of the rotary kiln dryer. The wind system has three parts. When the concentrate enters the kiln from the kiln tail, its humidity is the highest, and it is most likely to form nodules on the lifting plate, so the air volume supplied to this part should be the largest, followed by the air volume in the middle, and the smallest air volume in the head. The specific air volume ratio can be determined according to the site. Adjust the actual situation.

Wherein, as shown in Fig. 5-9, the hot air from the hot air stove enters the kiln wall air supply system along the air supply pipeline 17. The high-temperature and high-pressure air (hot air) in the air inlet branch pipe 10 enters from the hollow air chamber of the high-pressure air cushion type lifting plate 8, and is sprayed into the kiln through the air spray hole 83 arranged on the steel shell 81 of the lifting plate. A layer of air cushion is formed on the outer surface of the lifting plate 8 to protect the lifting plate 8 and strengthen the effect of breaking up materials, changing the way in which hot air enters the kiln head in the prior art.

Unless otherwise specified, the connection of each structure of the concentrate drying system of the rotary kiln dryer in the embodiment of the present invention is connected through the air supply pipeline 17, and multiple release points are set on the air supply pipeline 17 to ensure that the air supply pipeline Wind flow balance in Road 17.

Further preferably, as shown in Figure 5, the concentrate drying system of the rotary kiln dryer in the embodiment of the present invention also includes a flow detection and control device, and a flow control valve 16 and a flow detection device 15 are provided on the air supply pipeline 17, When the system is running, the opening of the control valve can be adjusted according to the detected real-time flow, so as to ensure the reasonable distribution of air flow values in various places.

During the construction of the rotary kiln dryer 2 (also known as the drying kiln) and the high-pressure air cushion type lifting plate 8, the kiln shell 7 of the drying kiln must be opened at the corresponding position where the lifting plate 8 is installed, so that the air inlet branch pipe 10 is connected with the hollow air chamber 82 of the lifting plate 8, so that the hot air can enter the inside of the lifting plate 8 smoothly.

As shown in Figure 11-13, the arrow indicates the direction of rotation, and the refractory lining 6 of the drying kiln must be constructed using the on-site formwork method of ramming material. The construction starts from a certain place. Continue to construct the second section of refractory lining 62 at an angle, and repeat in turn until the construction of the entire circle of refractory lining 6 is completed, so as to protect the blast hole 83 of the lifting plate 8 from entering the refractory powder.

When the concentrate drying system of the rotary kiln dryer according to the embodiment of the present invention is used for production, the hot air generated in the hot blast furnace 1 enters the kiln wall air supply system along the air supply pipeline 17, and a flow control is provided on the air supply pipeline 17. The valve 16 and the flow detection device 15 adjust and control the opening of the valve according to the detected real-time flow, so as to ensure the reasonable distribution of airflow values in various places. The hot air first enters the connecting pipe 9, then enters the annular air inlet main pipe 11, then enters the air inlet branch pipe 10 and the hollow air chamber 82 inside the lifting plate 8, and finally passes through the air blowing holes 83 arranged on the steel shell 81 of the lifting plate. Spray into the kiln. Affected by the negative pressure of the circulating fan 14, the hot air in the kiln will leave the rotary kiln dryer 2 from the kiln tail box 21, and then pass through the cyclone dust collector 3, the moisture absorber 12 and the circulation along the return hot air pipeline 13. The blower fan 14 finally gets back in the hot blast stove 1 to complete an air circulation process. At the same time, the direction of the material flow in the rotary kiln dryer 2 is to enter the rotary kiln dryer 2 from the kiln tail box 21 , to contact with the air flow in the opposite direction in the kiln, and finally to be discharged from the kiln head box 22 .

Using the concentrated ore drying system of the rotary kiln dryer of the present invention can effectively prolong the service life of the lifting plate, strengthen the lifting effect of the lifting plate, and reduce energy consumption while increasing the operating rate. Compared with the existing drying system, it is more energy-saving, economical, reliable and environmentally friendly, and it can be predicted that it has great development potential in the future market.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (6)

1. A rotary kiln dryer concentrate drying system, the system includes a hot blast stove, a rotary kiln dryer, the rotary kiln dryer includes a kiln shell, a kiln head box and a kiln tail box, it is characterized in that the system It also includes a lifting plate and a high-temperature flue gas circulation loop, the lifting plate is uniformly fixed on the kiln shell, and the kiln shell is connected to the hot blast stove; the high-temperature flue gas circulation loop includes a cyclone dust collector, a moisture absorber, One end of the primary cyclone dust collector is connected to the kiln tail box, and the other end is connected to the moisture absorber; one end of the circulation fan is connected to the moisture absorber, and the other end is connected to the hot blast stove. The equipment in the high-temperature flue gas circulation loop is connected through the return hot air pipeline; The lifting plate is a high-pressure air cushion type lifting plate, which is evenly fixed on the kiln shell along the circumferential direction of the rotary kiln dryer, and the inner wall of the kiln shell is poured with a dry kiln refractory lining. The high-pressure air cushion type lifting plate is a hollow structure, which is composed of a steel shell of the lifting plate and a hollow air chamber arranged inside the lifting plate. The hollow air chamber is close to the inner surface of the steel shell of the lifting plate. The plate steel shell is provided with blast holes, and the blast holes are arranged above the burial height of the refractory inner lining. 2. The system according to claim 1, characterized in that the ratio of the volume of fresh air entering the hot blast stove to the volume of circulating air is 3:1. 3. The system according to claim 1, characterized in that the concentrate drying system of the rotary kiln dryer also includes a kiln wall air supply system, and the high-pressure air pad type lifting plate is connected with hot air through the kiln wall air supply system. Furnace connection, the kiln wall air supply system includes an air supply pipeline, a connecting pipe, an annular air inlet main pipe and an air inlet branch pipe, one end of the connecting pipe is connected to the hot blast furnace through the air supply pipeline, and the other end is connected to the annular air inlet main pipe The air inlet branch pipes are evenly distributed in the kiln circumferential direction with the kiln center as the center of the circle. One end of the air inlet branch pipes is connected to the annular air inlet main pipe, and the other end is inserted into the kiln, and the high-pressure air cushion type lift at the corresponding position The sheets are connected. 4. The system according to claim 3, characterized in that, the kiln wall air supply system is the head kiln wall air supply system, the middle kiln wall air supply system or the tail kiln wall along the axial direction of the rotary kiln dryer. Air supply system. 5. The system according to claim 3, characterized in that the concentrate drying system of the rotary kiln dryer further includes a flow detection and control device, and a flow control valve and a flow detection device are installed on the air supply pipeline. 6. A concentrate drying method based on the concentrate drying system of the rotary kiln dryer according to any one of claims 1-5, characterized in that, the method is as follows: the hot blast generated in the hot blast stove passes along the air supply pipeline Enter the kiln wall air supply system, and then adjust and control the flow control valve and flow detection device on the air supply pipeline. The hot air first enters the connecting pipe, then enters the annular air intake main pipe, and then enters the air intake branch pipe and high-pressure air cushion type lifting material. The hollow air chamber inside the plate is finally sprayed into the kiln from the air injection hole arranged on the steel shell of the lifting plate, and the hot air leaves the rotary kiln dryer from the kiln tail box, and then passes through the hot air return line once respectively. The cyclone dust collector, moisture absorber and circulating fan finally return to the hot blast stove to complete a wind circulation process; at the same time, the material flow in the rotary kiln dryer enters the rotary kiln dryer from the kiln tail box, and reverses the wind flow in the kiln contact and eventually discharge from the kiln head box.