Multi-return-stroke suspension kiln

Abstract

The multi-return-stroke suspension kiln comprises a hot-blast stove and a first connecting pipe, the hot-blast stove is connected with the first connecting pipe, the first connecting pipe is upwards connected with a first ascending pipe, a discharging pipe is arranged on one side of the lower portion of the first ascending pipe, and the output end of the first ascending pipe is connected with a top bent pipe. The multi-return-stroke suspension kiln is provided with a hot-blast stove, a first connecting pipe, a discharging pipe, a first ascending pipe, a top bent pipe, a descending pipe, a second connecting pipe, a bottom bent pipe, a third connecting pipe, a second ascending pipe and a discharging pipe, and when powder reaches the second connecting pipe, due to the fact that the sectional area of the top of the second connecting pipe is twice that of the bottom of the second connecting pipe, the smoke flow speed is doubled; the conveying capacity of the flue gas to the powder is further enhanced at the higher flue gas flow speed, the number of return strokes can be increased or decreased, the height of the suspension kiln under the same retention time can be controlled, the number of the return strokes can be increased, the original suspension kiln with the high height is reduced, and therefore the construction difficulty and cost are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of suspension calcination, in particular to a multi-return suspension kiln. Background Art

[0002] Suspension calcination is a new type of calcination technology, which is characterized by first grinding the material into fine powder, then preheating it in a cyclone preheater, calcining it in a suspension kiln, and cooling it in a cyclone cooler to obtain the finished product. Since the material is calcined in the kiln in a fine powder state, this technology has the advantages of fast material decomposition rate, short calcination time, low energy consumption per unit product, and low nitrogen oxide generation.

[0003] Although the time required for calcining the material in a fine powder state is greatly reduced from several hours to several seconds, a high flue gas flow rate must be provided to maintain the material in a fluidized state. Therefore, even a calcination time of just a few seconds usually requires an extremely long kiln chamber length. Most existing suspension kilns adopt a combined structure of "riser-elbow-downer". Theoretically, as long as the length of the riser and downer is increased, the time required for powder calcination can be met. However, excessively high suspension kiln height processing will not only increase construction costs, but also increase the difficulty of later maintenance.

[0004] Therefore, a multi-return suspension kiln is needed to solve the above technical defects. Utility Model Content

[0005] The utility model aims to provide a multi-return suspension kiln to solve the problems of high construction cost and great difficulty in subsequent maintenance of the combined structure of "rising pipe-bend pipe-down pipe" proposed in the above background technology.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a multi-return suspension kiln, comprising a hot blast furnace and a first connecting pipe, the hot blast furnace is connected to the first connecting pipe, the first connecting pipe is upwardly connected to a first ascending pipe, a discharge pipe is arranged on one side below the first ascending pipe, the output end of the first ascending pipe is connected to a top bent pipe, the top bent pipe is bent downward and connected to a down pipe, the down pipe is vertically connected to a second connecting pipe downward, the output end of the second connecting pipe is connected to a bottom bent pipe, the output end of the bottom bent pipe is connected to a third connecting pipe, the pipe section from the first ascending pipe to the third connecting pipe is a single return structure, two groups of single return structures are added to the output end of the third connecting pipe and are connected to the second ascending pipe, and the output end of the second ascending pipe is connected to a discharge pipe.

[0007] Preferably, the single return structure formed by the first rising pipe to the third connecting pipe can be repeatedly assembled 1-5 times.

[0008] Preferably, the top cross-sectional area of ​​the first connecting pipe is 0.4-0.8 times the bottom cross-sectional area.

[0009] Preferably, a spreading tray is provided in the discharge pipe, and the surface of the spreading tray faces the center line of the first ascending pipe.

[0010] Preferably, the top cross-sectional area of ​​the second connecting pipe and the third connecting pipe is 1.5-3 times the bottom cross-sectional area.

[0011] Preferably, the single return structure after the first riser is arranged in alignment on the same plane, or is arranged in a bent manner on multiple planes.

[0012] Preferably, the first ascending pipe and the descending pipe are arranged in parallel in the vertical direction.

[0013] Compared with the prior art, the utility model has the following beneficial effects: the multi-return suspension kiln not only reduces the construction cost and the difficulty of later maintenance, but also reduces the probability of powder material depositing on the bend pipe at the bottom of the suspension kiln, improves the stability of equipment operation, and facilitates planning and layout, thereby improving the utilization rate of the site;

[0014] (1) A hot blast furnace, a first connecting pipe, a discharge pipe, a first ascending pipe, a top elbow, a down pipe, a second connecting pipe, a bottom elbow, a third connecting pipe, a second ascending pipe, and a discharge pipe are provided. The hot flue gas generated by the hot blast furnace increases in velocity after passing through the first connecting pipe, and then enters the first ascending pipe, mixes with the powder scattered from the side discharge pipe, and flows upward with the powder. In the process of the hot flue gas carrying the powder, the powder continuously absorbs the heat of the flue gas, the temperature rises, and a decomposition reaction occurs. When the hot flue gas and the powder pass through the first ascending pipe, the top elbow, and the down pipe in sequence and reach the second connecting pipe, due to the cross-sectional area at the top of the second connecting pipe, the hot flue gas and the powder are mixed with the powder scattered from the side discharge pipe, and the powder flows upward. The volume is twice that of the bottom, and the flue gas flow rate is doubled. The higher flue gas flow rate further enhances the flue gas's ability to transport powder, allowing the powder to overcome the influence of gravity and not settle in the bottom elbow. When the flue gas brings the powder out of the bottom elbow, a higher flow rate is no longer needed. Therefore, the flue gas flow rate is reduced again through the third pipe. After the flue gas carrying the powder repeats the process from the first riser to the third pipe twice, the calcination reaction is basically completed. Therefore, it enters the second riser and leaves from the discharge pipe, ensuring that the powder stays in the suspension furnace for an unchanged time, while reducing the height of the equipment, thereby reducing construction costs and reducing the difficulty of later maintenance.

[0015] (2) By providing a second connecting pipe and a bottom elbow, both of which are reducer pipes, the flow rate of flue gas in the bottom elbow can be increased, the probability of blockage can be greatly reduced, and the stability of equipment operation can be improved;

[0016] (3) By providing a first connecting pipe, a discharge pipe, a first ascending pipe, a top bent pipe, a descending pipe, a second connecting pipe, a bottom bent pipe, a third connecting pipe, a second ascending pipe, and a discharge pipe, a plurality of ascending pipes and descending pipes of the suspension kiln can be arranged in an aligned manner on the same plane or bent in a plurality of planes. Different suspension kilns can be planned and arranged according to the specific site selection and specification restrictions of the factory building, thereby improving the utilization rate of the site and reducing the site cost, and the final product has a more economical benefit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a front view structural schematic diagram of the utility model;

[0018] Figure 2 It is a top view layout diagram of the utility model;

[0019] Figure 3 This is a schematic diagram of the three-dimensional structure of the second connecting pipe of the utility model;

[0020] Figure 4 It is a schematic diagram of the three-dimensional structure of the first connecting pipe of the utility model.

[0021] In the figure: 1, hot air furnace; 2, first connecting pipe; 3, discharge pipe; 4, first ascending pipe; 5, top bent pipe; 6, descending pipe; 7, second connecting pipe; 8, bottom bent pipe; 9, third connecting pipe; 10, second ascending pipe; 11, discharge pipe. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] Example 1: Please refer to Figure 1-4 A multi-return suspension kiln comprises a hot blast furnace 1 and a first connecting pipe 2, the hot blast furnace 1 is connected to the first connecting pipe 2, the first connecting pipe 2 is upwardly connected to the first ascending pipe 4, a discharge pipe 3 is arranged on one side below the first ascending pipe 4, the output end of the first ascending pipe 4 is connected to the top bent pipe 5, the top bent pipe 5 is bent downward and connected to the down pipe 6, the down pipe 6 is vertically downwardly connected to the second connecting pipe 7, the output end of the second connecting pipe 7 is connected to the bottom bent pipe 8, the output end of the bottom bent pipe 8 is connected to the third connecting pipe 9, the pipe section from the first ascending pipe 4 to the third connecting pipe 9 is a single return structure, two groups of single return structures are added to the output end of the third connecting pipe 9 and are connected to the second ascending pipe 10, the output end of the second ascending pipe 10 is connected to the discharge pipe 11, and a material spreading plate is arranged in the discharge pipe 3, and the surface of the material spreading plate faces the center line of the first ascending pipe 4;

[0024] Specifically, Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the hot flue gas generated by the combustion of the hot blast furnace 1 increases its flow rate after passing through the first connecting pipe 2, and then enters the first ascending pipe 4, mixes with the powder scattered from the side discharge pipe 3, and flows upward with the powder. In the process of the hot flue gas carrying the powder, the powder continuously absorbs the heat of the flue gas, the temperature rises and a decomposition reaction occurs. When the hot flue gas and the powder pass through the first ascending pipe 4, the top elbow 5 and the downcomer 6 in sequence and reach the second connecting pipe 7, since the cross-sectional area of ​​the top of the second connecting pipe 7 is twice that of the bottom, the flue gas flow rate doubles. The higher flue gas flow rate further enhances the flue gas's ability to transport the powder, so that the powder overcomes the influence of gravity and will not be deposited in the bottom elbow 8. After the flue gas brings the powder out of the bottom elbow 8, a higher flow rate is not required. Therefore, the flue gas flow rate is reduced again through the third connecting pipe 9. After the powder carried by the flue gas repeats the process between the first ascending pipe 4 and the third connecting pipe 9 twice, the calcination is basically completed. Therefore, it enters the second ascending pipe 10 and leaves from the discharge pipe 11. The height of the suspension kiln under the same residence time can be controlled by increasing or decreasing the number of return trips. Embodiment 2: The top cross-sectional area of ​​the first connecting pipe 2 is 0.4-0.8 times the bottom cross-sectional area, and the top cross-sectional area of ​​the second connecting pipe 7 and the third connecting pipe 9 is 1.5-3 times the bottom cross-sectional area;

[0025] Specifically, Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the second connecting pipe 7 and the bottom elbow 8 are both reducers, which can increase the flow rate of the flue gas in the bottom elbow 8, thereby ensuring that powder will not accumulate in the bottom elbow 8, and there will not be much powder deposition at the bends of each pipe section, so there will be less corrosion and blockage in the pipe.

[0026] Embodiment 3: A single return structure formed by the first ascending pipe 4 to the third connecting pipe 9 can be repeatedly assembled 1-5 times, and the single return structure after the first ascending pipe 4 is arranged in alignment on the same plane, or bent on multiple planes, and the first ascending pipe 4 and the descending pipe 6 are arranged in parallel in the vertical direction;

[0027] Specifically, Figure 1 and Figure 2 As shown, multiple ascending and descending pipelines of the suspension kiln can be arranged in alignment on the same plane or bent on multiple planes. Different suspension kilns can be planned and arranged according to the specific site selection and specification restrictions of the plant. The height of the suspension kiln is reduced, and the construction cost and difficulty are reduced.

[0028] Working principle: The hot flue gas generated by the combustion of the hot blast furnace 1 increases its flow rate after passing through the first connecting pipe 2, and then enters the first ascending pipe 4, mixes with the powder scattered from the side discharge pipe 3, and flows upward with the powder. In the process of the hot flue gas carrying the powder, the powder continuously absorbs the heat of the flue gas, the temperature rises and a decomposition reaction occurs. When the hot flue gas and the powder pass through the first ascending pipe 4, the top elbow 5 and the downcomer 6 in sequence and reach the second connecting pipe 7, since the cross-sectional area of ​​the top of the second connecting pipe 7 is twice that of the bottom, the flue gas flow rate doubles. The higher flue gas flow rate further enhances the flue gas's ability to transport the powder, so that the powder overcomes the influence of gravity and will not be deposited in the bottom elbow 8. After the flue gas brings the powder out of the bottom elbow 8, a higher flow rate is no longer required. Therefore, the flue gas flow rate is reduced again through the third connecting pipe 9. After the powder carried by the flue gas repeats the process between the first ascending pipe 4 and the third connecting pipe 9 twice, the calcination reaction is basically completed, so it enters the second ascending pipe 10 and leaves from the discharge pipe 11.

[0029] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A multi-pass suspension kiln, comprising a hot blast furnace (1) and a first connecting pipe (2), characterized in that: The hot blast furnace (1) is connected to a first connecting pipe (2), the first connecting pipe (2) is upwardly connected to a first ascending pipe (4), a discharge pipe (3) is arranged on one side below the first ascending pipe (4), the output end of the first ascending pipe (4) is connected to a top bent pipe (5), the top bent pipe (5) is bent downward and connected to a down pipe (6), the down pipe (6) is vertically connected to a second connecting pipe (7) downward, the output end of the second connecting pipe (7) is connected to a bottom bent pipe (8), the output end of the bottom bent pipe (8) is connected to a third connecting pipe (9), the pipe section from the first ascending pipe (4) to the third connecting pipe (9) is a single return structure, two groups of single return structures are added to the output end of the third connecting pipe (9) and are connected to the second ascending pipe (10), the output end of the second ascending pipe (10) is connected to a discharge pipe (11).

2. A multi-pass suspension kiln according to claim 1, characterized in that: The single return structure formed by the first rising pipe (4) to the third connecting pipe (9) can be repeatedly assembled 1 to 5 times.

3. A multi-pass suspension kiln according to claim 1, characterized in that: The top cross-sectional area of ​​the first connecting pipe (2) is 0.4-0.8 times the bottom cross-sectional area.

4. A multi-pass suspension kiln according to claim 1, characterized in that: A material spreading plate is arranged in the lower material pipe (3), and the surface of the material spreading plate faces the center line of the first ascending pipe (4).

5. The multi-pass suspension kiln according to claim 1, characterized in that: The top cross-sectional area of ​​the second connecting pipe (7) and the third connecting pipe (9) is 1.5-3 times the bottom cross-sectional area.

6. A multi-pass suspension kiln according to claim 1, characterized in that: The single return structure after the first ascending pipe (4) is arranged in alignment on the same plane, or is arranged in a bent manner on multiple planes.

7. The multi-pass suspension kiln according to claim 1, characterized in that: The first ascending pipe (4) and the descending pipe (6) are arranged in parallel in the vertical direction.

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