A material preheating system based on lithium ore roasting line and its adjusting method
The material preheating system, which combines a rotary preheater and a cyclone preheater, solves the problems of difficult adjustment of material preheating effect and high equipment cost in lithium ore roasting, and achieves efficient and low-resistance material preheating and dust removal.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MOUNTOP GRP CO LTD
- Filing Date
- 2023-08-28
- Publication Date
- 2026-07-24
AI Technical Summary
In existing lithium ore roasting processes, the preheating effect of materials is not easy to adjust, the equipment is bulky and expensive, and the system resistance is large, resulting in high energy consumption and high equipment costs.
The material preheating system, which combines a rotary preheater and a cyclone preheater, uses a high-temperature resistant airflow regulating valve and a material distribution valve to separate the material from the high-temperature flue gas. Combined with the lifting plates and drive device inside the horizontal rotary drum, it achieves efficient material preheating and dust removal in the cyclone preheater, reducing system resistance.
It enables flexible adjustment of material preheating effect, avoids excessive drying of materials, reduces equipment cost and system resistance, improves preheating efficiency and dust removal efficiency, and extends the service life of dust collector filter bags.
Smart Images
Figure CN117168169B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium ore roasting, and more particularly to a material preheating system and its regulation method. Background Technology
[0002] The tail gas temperature of the lepidolite / spodumene roasting kiln is 450-500℃. In order to save energy and reduce energy consumption, the high-temperature tail gas is utilized. The traditional process is to use a vertical preheater at the kiln tail to dry and preheat the material to be roasted.
[0003] The current disadvantages of vertical preheaters at the kiln tail are: the preheating effect of materials is not easy to adjust; when the initial moisture content of the materials is not high, they will be over-dried; in addition, the civil engineering and equipment costs of using vertical preheaters at the kiln tail are high, and the system resistance is large, with the maximum resistance reaching 2500Pa. Summary of the Invention
[0004] Purpose of the invention: The purpose of this invention is to provide a material preheating system and its adjustment method based on a lithium ore roasting line, overcoming the disadvantages of difficult adjustment of material preheating effect, large equipment size, high cost, and high system resistance.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A material preheating system based on a lithium ore roasting line includes a roasting kiln, a preheater, and a material conveyor. The preheater comprises a rotary preheater and a cyclone preheater. The rotary preheater includes a horizontal rotary drum. The front end of the horizontal rotary drum is connected to the rear end of the roasting kiln via a first connecting hood. The rear end of the horizontal rotary drum is provided with a second connecting hood. A high-temperature resistant airflow regulating valve is installed at the air outlet of the first connecting hood. The high-temperature resistant airflow regulating valve is connected to the air inlet of the cyclone preheater. The material conveyor's discharge end is connected to the inlet of a material distribution valve. The first outlet of the material distribution valve is connected to the inlet of the cyclone preheater. The second outlet of the material distribution valve and the outlet of the cyclone preheater are connected to the inlet of the second connecting hood. The air outlets of the cyclone preheater and the second connecting hood are connected to a dust collector.
[0007] Furthermore, the high-temperature resistant air volume regulating valve is connected to the air inlet of the cyclone preheater through the first air duct, the air outlet of the cyclone preheater is connected to the dust collector through the second air duct, and the air outlet of the second connecting hood is connected to the dust collector through the third air duct.
[0008] Furthermore, the first discharge port of the material distribution valve is connected to the inlet of the cyclone preheater through a first discharge chute, the discharge port of the cyclone preheater is connected to the inlet of the second connecting hood through a second discharge chute, and the second discharge port of the material distribution valve is connected to the inlet of the second connecting hood through a third discharge chute.
[0009] Furthermore, the horizontal rotary drum is provided with a lifting plate on the inner side and a driving device on the outer side.
[0010] A method for regulating a material preheating system based on a lithium ore roasting line, the method comprising:
[0011] Under normal operating conditions, the material moisture content is 13-18%. The material distribution valve does not divert the material to be roasted. All materials are preheated through the rotary preheater. At the same time, the high-temperature air volume regulating valve is closed, and all the high-temperature exhaust gas discharged from the roasting kiln is introduced into the rotary preheater to achieve material preheating. This results in the preheated material moisture content being 4%-6%, and the exhaust gas temperature at the dust collector inlet being 130-160℃.
[0012] When the moisture content of the material is less than 10%, the material distribution valve does not divert the material to be roasted. All materials are preheated through the rotary preheater. At the same time, the high-temperature exhaust gas discharged from the roasting kiln is diverted through the high-temperature air volume regulating valve. 15% to 30% of the high-temperature exhaust gas is fed into the cyclone preheater, and the rest is fed into the rotary preheater to achieve material preheating.
[0013] With the high-temperature airflow regulating valve diverting the high-temperature exhaust gas, the exhaust gas temperature at the dust collector inlet is detected. Under the premise of keeping the opening of the high-temperature airflow regulating valve constant, when the exhaust gas temperature is greater than 180°, the material to be roasted is diverted through the material distribution valve. 15-30% of the material is diverted to the cyclone preheater for preheating, and the rest is fed into the rotary preheater for preheating, so that the moisture content of the preheated material is 4%-6% and the exhaust gas temperature at the dust collector inlet is 130-160°C.
[0014] Furthermore, during the preheating process of the material in the rotary preheater, the discharge time of the rotary preheater is adjusted by regulating the rotation speed of the horizontal rotary drum.
[0015] Beneficial effects:
[0016] The material preheating system provided by this invention can determine whether it is necessary to separate the material to be roasted and the high-temperature flue gas according to the initial moisture content of the material, which overcomes the disadvantage that the preheating effect of the material dried in the hot kiln is not easy to adjust and prevents the moisture content of the material after preheating from being too low.
[0017] The material preheating system provided by this invention uses a rotary preheater to dry the material. The high-temperature flue gas comes into direct contact with the material in the rotary preheater, and the material is preheated through convection heat transfer and thermal radiation, resulting in a better preheating effect.
[0018] The high-temperature flue gas is preheated by a cyclone preheater to remove dust in advance, which avoids dust accumulation in the downstream pipeline, reduces the load on the downstream dust collector, and extends the service life of the dust collector filter bags. After the diverted high-temperature flue gas passes through the cyclone dust collector, it enters the dust collector. The cyclone dust collector can achieve a dust removal efficiency of up to 85%.
[0019] Under the same material and exhaust gas conditions, the rotary drum heat exchanger has high efficiency. The resistance loss of the rotary drum is about 95 Pa. The cyclone preheater of the present invention is a single-stage cyclone, and its resistance loss can be reduced to about 300 Pa, making the resistance loss of the entire system smaller. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the material preheating system of the present invention.
[0021] In the diagram: 1-Dust collector; 2-Cyclone preheater; 3-Material distribution valve; 4-High temperature resistant air volume regulating valve; 5-Rotary preheater; 6-Second connecting hood; 7-First connecting hood; 8-Caking kiln; 9-Drive device; 10-Material conveyor; 11-First discharge chute; 12-Second discharge chute; 13-Third discharge chute; 14-First air duct; 15-Second air duct; 16-Third air duct. Detailed implementation method:
[0022] The invention will now be further explained with reference to the accompanying drawings.
[0023] like Figure 1 As shown, the present invention discloses a material preheating system based on a lithium ore roasting line, comprising a roasting kiln 8, a preheater, and a material conveyor 10. The preheater includes a rotary preheater 5 and a cyclone preheater 2. The rotary preheater includes a horizontal rotary drum. The front end of the horizontal rotary drum is connected to the tail end of the roasting kiln 9 via a first connecting cover 7. The tail end of the horizontal rotary drum is provided with a second connecting cover 6. A high-temperature resistant airflow regulating valve 4 is provided at the air outlet of the first connecting cover 7. The high-temperature resistant airflow regulating valve 4 is connected to the air inlet of the cyclone preheater 2. The material conveyor 10 is connected to the inlet of a material distribution valve 3 at the material discharge end. The first outlet of the material distribution valve 3 is connected to the inlet of the cyclone preheater 2. The second outlet of the material distribution valve 3 and the outlet of the cyclone preheater 2 are connected to the inlet of the second connecting cover 7. The air outlets of the cyclone preheater 2 and the second connecting cover 6 are connected to a dust collector 1.
[0024] like Figure 1 As shown, in this embodiment, the high-temperature resistant air volume regulating valve 4 is connected to the air inlet of the cyclone preheater 2 through the first air duct 14, the air outlet of the cyclone preheater 2 is connected to the dust collector 1 through the second air duct 15, and the air outlet of the second connecting cover 6 is connected to the dust collector 1 through the third air duct 15.
[0025] The first discharge port of the material distribution valve 3 is connected to the inlet of the cyclone preheater 2 through the first discharge chute 11. The discharge port of the cyclone preheater 2 is connected to the inlet of the second connecting cover 6 through the second discharge chute 13. The second discharge port of the material distribution valve 3 is connected to the inlet of the second connecting cover 6 through the third discharge chute 13.
[0026] The rotary preheater 5 has a lifting plate on the inner side of its horizontal rotary drum. During the rotation of the horizontal rotary drum, the material can be lifted up and fully contacted with the high-temperature flue gas to achieve a better preheating effect. The rotary preheater 5 has a drive device 9 on the outer side of its horizontal rotary drum to drive the horizontal rotary drum to rotate.
[0027] Under the same material and exhaust gas conditions, rotary preheaters have higher heat exchange efficiency. Φ Taking the 3.4×11m rotary drum as an example, the exhaust gas processing capacity is 120,000 m³ / hour. 3 The initial temperature of the exhaust gas is 350℃, and the flow velocity of the exhaust gas at the cross-section of the rotating drum is approximately 3.6 m / s. The resistance loss of the entire rotating drum is approximately 95 Pa. The cyclone preheater of this invention is a single-stage cyclone, and its resistance loss can be reduced to approximately 300 Pa. Compared with traditional vertical preheaters, to achieve the same preheating effect, at least three stages of cyclone preheating in series are required, with each stage of the preheater having a resistance loss of approximately 600–800 Pa.
[0028] This invention determines whether it is necessary to separate the material to be roasted from the high-temperature flue gas based on the initial moisture content of the material and the temperature of the exhaust gas. On the one hand, it prevents the moisture content of the preheated material from being too low, and on the other hand, it controls the temperature of the exhaust gas entering the dust collector. When the exhaust gas temperature is too low (below the dew point temperature of sulfur dioxide), corrosion is likely to occur, and when the exhaust gas temperature is too high, it will damage the subsequent dust removal equipment.
[0029] The present invention discloses a method for adjusting a material preheating system based on a lithium ore roasting line, the method comprising:
[0030] Under normal operating conditions, the material moisture content is 13-18%. The material distribution valve does not divert the material to be roasted. All materials are preheated through the rotary preheater. At this time, the high-temperature air volume regulating valve is closed, and all the high-temperature exhaust gas discharged from the roasting kiln is introduced into the rotary preheater to achieve material preheating. This results in the preheated material moisture content being 4%-6%, and the exhaust gas temperature at the dust collector inlet being 130-160℃.
[0031] When the moisture content of the material is less than 10%, the material distribution valve does not divert the material to be roasted. All materials are preheated through the rotary preheater. At this time, the high-temperature exhaust gas discharged from the roasting kiln is diverted through the high-temperature air volume regulating valve. 15% to 30% of the high-temperature exhaust gas is fed into the cyclone preheater, and the rest is fed into the rotary preheater to achieve material preheating.
[0032] With the high-temperature airflow regulating valve diverting the high-temperature exhaust gas, the exhaust gas temperature at the dust collector inlet is monitored. While maintaining a constant opening of the high-temperature airflow regulating valve, when the exhaust gas temperature exceeds 180°C, adjustment measures are needed to lower the exhaust gas temperature. The material to be roasted is then diverted via the material distribution valve, with 15-30% of the material being preheated in the cyclone preheater, and the remainder being preheated in the rotary preheater. This results in a preheated material with a moisture content of 4-6% and an exhaust gas temperature of 130-160°C at the dust collector inlet.
[0033] During the preheating process of materials in the rotary preheater, the discharge time of the rotary preheater is adjusted by regulating the rotation speed of the horizontal rotary drum.
[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for adjusting a material preheating system based on a lithium ore roasting line, characterized in that: The material preheating system includes a calcining kiln, a preheater, and a material conveyor. The preheater comprises a rotary preheater and a cyclone preheater. The rotary preheater includes a horizontal rotary drum. The front end of the horizontal rotary drum is connected to the rear end of the calcining kiln via a first connecting hood. The rear end of the horizontal rotary drum is provided with a second connecting hood. A high-temperature resistant airflow regulating valve is installed at the air outlet of the first connecting hood. The high-temperature resistant airflow regulating valve is connected to the air inlet of the cyclone preheater. The material conveyor's discharge end is connected to the inlet of a material distribution valve. The first outlet of the material distribution valve is connected to the inlet of the cyclone preheater. The second outlet of the material distribution valve and the outlet of the cyclone preheater are connected to the inlet of the second connecting hood. The air outlets of the cyclone preheater and the second connecting hood are connected to a dust collector. The adjustment method includes: under normal operating conditions, the material moisture content is 13-18%, the material distribution valve does not divert the material to be roasted, all materials are preheated through the rotary preheater, and at the same time the high temperature air volume regulating valve is closed, and all the high temperature exhaust gas discharged from the roasting kiln is introduced into the rotary preheater to achieve material preheating, so that the moisture content of the preheated material is 4%-6%, and the exhaust gas temperature at the dust collector inlet is 130-160℃; When the moisture content of the material is less than 10%, the material distribution valve does not divert the material to be roasted. All materials are preheated through the rotary preheater. At the same time, the high-temperature exhaust gas discharged from the roasting kiln is diverted through the high-temperature air volume regulating valve. 15% to 30% of the high-temperature exhaust gas is fed into the cyclone preheater, and the rest is fed into the rotary preheater to achieve material preheating. With the high-temperature airflow regulating valve diverting the high-temperature exhaust gas, the exhaust gas temperature at the dust collector inlet is detected. Under the premise of keeping the opening of the high-temperature airflow regulating valve constant, when the exhaust gas temperature is greater than 180°, the material to be roasted is diverted through the material distribution valve. 15-30% of the material is diverted to the cyclone preheater for preheating, and the rest is fed into the rotary preheater for preheating, so that the moisture content of the preheated material is 4%-6% and the exhaust gas temperature at the dust collector inlet is 130-160°C.
2. The method for adjusting a material preheating system based on a lithium ore roasting line according to claim 1, characterized in that: During the preheating process of materials in the rotary preheater, the discharge time of the rotary preheater is adjusted by regulating the rotation speed of the horizontal rotary drum.
3. The method for adjusting a material preheating system based on a lithium ore roasting line according to claim 1, characterized in that: The high-temperature resistant air volume regulating valve is connected to the air inlet of the cyclone preheater through the first air duct, the air outlet of the cyclone preheater is connected to the dust collector through the second air duct, and the air outlet of the second connecting hood is connected to the dust collector through the third air duct.
4. The method for adjusting a material preheating system based on a lithium ore roasting line according to claim 1, characterized in that: The first discharge port of the material distribution valve is connected to the inlet of the cyclone preheater through the first discharge chute, the discharge port of the cyclone preheater is connected to the inlet of the second connecting hood through the second discharge chute, and the second discharge port of the material distribution valve is connected to the inlet of the second connecting hood through the third discharge chute.
5. The method for adjusting a material preheating system based on a lithium ore roasting line according to claim 1, characterized in that: The horizontal rotary drum is equipped with a lifting plate on its inner side and a driving device on its outer side.