Kiln gas flow regulation system and method

Abstract

The present application provides a kind of kiln gas flow regulating system and method, for adjusting the gas flow of low activity gas in kiln in sintering process, kiln has sequentially communicated heating box, constant temperature box and cooling box.The kiln gas flow regulating system includes: heating section regulating unit, for controlling the gas flow in heating box gradually smaller from the inlet of heating box along the direction close to constant temperature box;Constant temperature section regulating unit, for controlling the gas flow in constant temperature box balanced;And cooling section regulating unit, for controlling the gas flow in cooling box gradually larger from the inlet of cooling box along the direction away from constant temperature box, the maximum gas flow in heating box is less than the maximum gas flow in cooling box.Kiln gas flow curve is U type with high back and low front, oxygen in kiln is discharged from back to front, accelerates gas flow and reduces oxygen content at the same time, constant temperature section gas flow is reduced, overall gas flow is reduced, and the use amount of low activity gas can be reduced.

Description

Technical Field

[0001] This invention belongs to the field of kiln sintering environment technology, specifically relating to a kiln gas flow regulation system and method. Background Technology

[0002] Typically, battery materials undergo a sintering process in a kiln during manufacturing. To prevent side reactions between the moisture, primarily oxygen, in the environment and the materials during sintering, which could affect product performance, sintering must be carried out in a low-activity gas environment. Current technology generally involves continuously introducing low-activity gas to exhaust the existing oxygen in the kiln through compression and the suction force of the exhaust fan.

[0003] However, in reality, it is difficult to completely remove oxygen from the kiln. A certain amount of oxygen can be tolerated without affecting product performance. Increasing the flow rate of inactive gases in pursuit of an oxygen-free environment can easily lead to waste of these gases and increased costs. Furthermore, the kiln sintering process includes heating, isothermal, and cooling sections, each with different oxygen content requirements. For example, the isothermal section requires an oxygen content below 1 PPM, while the cooling section requires below 30 PPM. Therefore, how to ensure that the oxygen content in each section of the kiln meets the requirements without wasting inactive gases, thereby reducing costs, is a topic worthy of research. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a kiln gas flow regulation system for adjusting the flow rate of low-activity gases within the kiln during the sintering process. The kiln comprises a heating chamber, a constant-temperature chamber, and a cooling chamber connected in sequence. The kiln gas flow regulation system includes: a heating section regulation unit for controlling the gas flow rate in the heating chamber to gradually decrease from the inlet of the heating chamber towards the constant-temperature chamber; a constant-temperature section regulation unit for controlling the gas flow rate to be balanced at various points within the constant-temperature chamber; and a cooling section regulation unit for controlling the gas flow rate in the cooling chamber to gradually increase from the inlet of the cooling chamber away from the constant-temperature chamber, wherein the maximum gas flow rate in the heating chamber is less than the maximum gas flow rate in the cooling chamber.

[0005] Preferably, the heating chamber, the constant temperature chamber, and the cooling chamber each have multiple air inlets, the heating chamber and the constant temperature chamber each have an air outlet, and the cooling chamber does not have an air outlet; the heating section adjustment unit, the constant temperature section adjustment unit, and the cooling section adjustment unit control the air flow rate by adjusting the air intake volume of the multiple air inlets of the heating chamber, the constant temperature chamber, and the cooling chamber, respectively.

[0006] Preferably, the air flow rate in the constant temperature chamber is equal to the minimum air flow rate in the heating chamber.

[0007] A method for regulating kiln gas flow is also provided, used to regulate the gas flow of low-activity gas in a kiln during the sintering process. The kiln has a heating chamber, a constant temperature chamber, and a cooling chamber connected in sequence. The method includes: controlling the gas flow in the heating chamber to gradually decrease from the inlet of the heating chamber towards the constant temperature chamber; controlling the gas flow to be balanced at all points in the constant temperature chamber; and controlling the gas flow in the cooling chamber to gradually increase from the inlet of the cooling chamber away from the constant temperature chamber, wherein the maximum gas flow in the heating chamber is less than the maximum gas flow in the cooling chamber.

[0008] Preferably, the air flow rate in the constant temperature chamber is equal to the minimum air flow rate in the heating chamber.

[0009] Preferably, the maximum airflow rate in the cooling box is determined based on the maximum pressure that the kiln body can withstand, and the maximum airflow rate in the cooling box is less than the maximum pressure that the kiln body can withstand.

[0010] Preferably, the maximum air flow rate of the heating chamber is greater than or equal to the air flow rate of each section, which can meet the oxygen content standard of the constant temperature chamber.

[0011] Preferably, the step of "controlling the air flow rate in the cooling box to gradually increase from the inlet of the cooling box away from the constant temperature box" includes controlling the air flow rate in the cooling box to gradually increase from the inlet of the cooling box away from the constant temperature box, and then gradually decrease.

[0012] Preferably, the airflow rate inside the cooling box is controlled to suddenly increase to a peak value and then gradually decrease.

[0013] Preferably, the peak value occurs in the range where the temperature in the cooling box is less than 40°C.

[0014] Preferably, the air flow rate of the constant temperature chamber is determined according to the maximum allowable oxygen content of the constant temperature chamber, so that the oxygen content in the constant temperature chamber is lower than the maximum allowable oxygen content.

[0015] The kiln gas flow regulation system provided by this invention has a kiln gas flow rate that is high at the front and back (heating and cooling sections) and low in the middle (constant temperature section), forming a U-shaped gas flow rate curve with the back being higher than the front. This allows oxygen in the kiln to be discharged from the back to the front, accelerating gas flow and reducing oxygen content. At the same time, the gas flow rate in the constant temperature section is reduced, and the overall gas flow rate is reduced, which can reduce the amount of low-activity gas used.

[0016] The flow rate of low-activity gas can be adjusted according to the different oxygen content requirements of the heating, isothermal and cooling sections. This also helps to control the gas input on demand, thereby reducing the waste of low-activity gas and lowering costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the air flow rate curve according to a specific embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the air flow rate curve according to another specific embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0020] The kiln has a front replacement chamber, a heating chamber, a constant temperature chamber, a cooling chamber, and a rear replacement chamber (none shown in the diagram) that are connected sequentially. The front and rear replacement chambers are each equipped with front and rear baffles. Lowering the front and rear baffles of the front replacement chamber creates a sealed space; similarly, the front and rear baffles of the rear replacement chamber can form sealed spaces. During the sintering process, the sagger containing the material to be sintered enters the front replacement chamber. Both the front and rear baffles of the front replacement chamber are lowered, a vacuum is created, and a low-activity gas is introduced. Then, the rear baffle of the front replacement chamber is raised, connecting the front replacement chamber to the heating chamber. The sagger is then conveyed by rollers into the heating chamber, constant temperature chamber, and cooling chamber sequentially, finally exiting from the rear replacement chamber, completing the sintering process. To prevent oxygen from entering the kiln through the replacement chambers, before the sagger enters the rear replacement chamber, the front and rear baffles of the rear replacement chamber are lowered, a vacuum is created, and a low-activity gas is introduced to ensure the oxygen content meets the standard before opening the front baffle of the rear replacement chamber, allowing the sagger to move from the cooling chamber into the rear replacement chamber.

[0021] Each temperature chamber can be divided into multiple air boxes. In the heating chamber, the air box closer to the constant temperature chamber has a higher temperature and approaches the temperature of the constant temperature chamber. In the cooling chamber, the air box further away from the constant temperature chamber has a lower temperature. The material is fully calcined and reacted in the constant temperature chamber, which has the highest temperature and the strictest oxygen content requirements. Its allowable oxygen content is lower than that of other temperature chambers. If the current technology is followed, a continuous supply of low-reactivity gas is required, with the gas flow rate being consistent throughout, and the oxygen environment conforming to the constant temperature chamber standard. This means that the gas flow rate throughout is equivalent to and at a high level compared to the constant temperature chamber, which easily leads to waste of low-reactivity gas.

[0022] The kiln gas flow regulation system of the present invention is applicable to kilns in which the heating box, constant temperature box, and cooling box are all provided with multiple air inlets, and even each air box or every two adjacent air boxes is provided with one air inlet. Low-activity gas can enter from multiple air inlets respectively. The heating box and constant temperature box are provided with air outlets, while the cooling box is not provided with an air outlet. The gas input from the cooling box is discharged from the constant temperature box and the heating box, forming a gas discharge trend from back to front.

[0023] The kiln gas flow regulation system includes a processor, comprising: a heating section regulation unit for controlling the gas flow rate in the heating chamber to gradually decrease from the inlet of the heating chamber towards the constant temperature chamber; a constant temperature section regulation unit for controlling the gas flow rate to be balanced throughout the constant temperature chamber, wherein the gas flow rate in the constant temperature chamber is equal to the minimum gas flow rate in the heating chamber; and a cooling section regulation unit for controlling the gas flow rate in the cooling chamber to gradually increase from the inlet of the cooling chamber away from the constant temperature chamber, wherein the maximum gas flow rate in the heating chamber is less than the maximum gas flow rate in the cooling chamber. The heating section regulation unit, the constant temperature section regulation unit, and the cooling section regulation unit control the gas flow rate by adjusting the air intake at multiple air inlets of the heating chamber, the constant temperature chamber, and the cooling chamber, respectively.

[0024] The kiln gas flow regulation system provided by this invention features a U-shaped gas flow curve with higher flow rates at the front and rear (heating and cooling sections) and lower flow rates in the middle (constant temperature section). This curve directs oxygen out of the kiln from back to front, accelerating gas flow and reducing oxygen content. Please refer to [reference needed]. Figure 1 Furthermore, the U-shaped gas flow curve only requires the peak sections at the beginning and end to be comparable to the gas flow rate of the constant temperature section in existing technologies. The gas flow rates in all other sections are lower than those in existing technologies, thus significantly reducing the overall gas flow rate and the amount of low-activity gas used.

[0025] The low-reactivity gas can be one or more of nitrogen (N2), helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and hydrogen (H2). Nitrogen, which is widely available and inexpensive, is preferred.

[0026] The kiln gas flow rate regulation method provided by the present invention includes the following steps: controlling the gas flow rate in the heating box to gradually decrease from the inlet of the heating box along the direction closer to the constant temperature box; controlling the gas flow rate at all points in the constant temperature box to be balanced, and the gas flow rate in the constant temperature box to be equal to the minimum gas flow rate in the heating box; and controlling the gas flow rate in the cooling box to gradually increase from the inlet of the cooling box along the direction away from the constant temperature box.

[0027] The maximum gas flow rate in the heating chamber is less than the maximum gas flow rate in the cooling chamber, which facilitates a gas discharge trend from back to front. The maximum gas flow rates in both the heating and cooling chambers are determined based on the maximum pressure the kiln body can withstand, or the gas flow rate that meets the oxygen content standard of the constant temperature chamber when the gas flow rates in each section are equal (i.e., the gas flow rate of the constant temperature section in the prior art). The maximum gas flow rate in the cooling chamber is less than the maximum pressure the kiln body can withstand, but greater than the gas flow rate of the constant temperature section in the prior art; the maximum gas flow rate in the heating chamber is less than the maximum pressure the kiln body can withstand, but greater than or equal to the gas flow rate of the constant temperature section in the prior art. In a preferred embodiment, the maximum gas flow rate in the heating chamber is comparable to the gas flow rate of the constant temperature section in the prior art, and the maximum gas flow rate in the cooling chamber is slightly less than the maximum pressure the kiln body can withstand.

[0028] In one embodiment, the step of "controlling the air flow rate in the cooling box to gradually increase from the inlet of the cooling box away from the constant temperature chamber" further includes controlling the air flow rate in the cooling box to gradually increase from the inlet of the cooling box away from the constant temperature chamber, and then gradually decrease. In this case, please refer to the air flow rate curve. Figure 2 Specifically, the airflow rate inside the cooling box is controlled to suddenly increase to a peak value, and then gradually decrease.

[0029] A temperature range with low temperature influence and small gas expansion is selected in the cooling section. A large air flow rate is then increased to create a peak value. This increased flow rate forms an "air wall" within this temperature range, blocking oxygen from flowing into the constant temperature chamber. After reaching the peak value, the air flow rate is gradually reduced, and the exhaust port of the rear replacement chamber is opened, allowing oxygen and low-activity gases to be discharged simultaneously, thus reducing the oxygen content. The peak air flow rate in the cooling chamber occurs in the temperature range below 40°C. In this range, gas expansion is small, and a sudden increase in air flow rate is unlikely to cause drastic pressure fluctuations within the kiln, thus preventing accidents.

[0030] The above embodiments are merely illustrative of the present invention and are not intended to limit the technical solutions described herein. Although this specification has described the present invention in detail with reference to the various embodiments described above, the present invention is not limited to the specific embodiments described. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Therefore, any modifications or equivalent substitutions to the present invention, and all technical solutions and improvements that do not depart from the spirit and scope of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A kiln gas flow regulation system for regulating the flow rate of low-activity gases in a kiln during the sintering process, wherein the kiln comprises a heating chamber, a constant temperature chamber, and a cooling chamber connected in sequence, characterized in that, The kiln gas flow regulation system includes: The heating section adjustment unit is used to control the air flow rate in the heating chamber to gradually decrease from the inlet of the heating chamber along the direction closer to the constant temperature chamber; The constant temperature section adjustment unit is used to control the airflow balance throughout the constant temperature chamber; and The cooling section adjustment unit is used to control the air flow rate in the cooling box to gradually increase from the inlet of the cooling box away from the constant temperature box, and the maximum air flow rate in the heating box is less than the maximum air flow rate in the cooling box.

2. The kiln gas flow regulation system as described in claim 1, characterized in that, The heating chamber, the constant temperature chamber, and the cooling chamber each have multiple air inlets, and the heating chamber and the constant temperature chamber each have an air outlet, while the cooling chamber does not have an air outlet. The heating section adjustment unit, the constant temperature section adjustment unit, and the cooling section adjustment unit control the air flow rate by adjusting the air intake volume of the multiple air inlets of the heating chamber, the constant temperature chamber, and the cooling chamber, respectively.

3. The kiln gas flow regulation system as described in claim 2, characterized in that, The air flow rate in the constant temperature chamber is equal to the minimum air flow rate in the heating chamber.

4. A method for regulating the gas flow rate in a kiln, used to regulate the gas flow rate of low-activity gases in a kiln during the sintering process, wherein the kiln has a heating chamber, a constant temperature chamber, and a cooling chamber connected in sequence, characterized in that... The method includes: The airflow rate inside the heating chamber is controlled to gradually decrease from the inlet of the heating chamber towards the constant temperature chamber; Controlling the airflow rate evenly throughout the constant temperature chamber; and The airflow rate in the cooling chamber is controlled to gradually increase from the inlet of the cooling chamber away from the constant temperature chamber, and the maximum airflow rate in the heating chamber is less than the maximum airflow rate in the cooling chamber.

5. The kiln gas flow rate adjustment method as described in claim 4, characterized in that, The air flow rate in the constant temperature chamber is equal to the minimum air flow rate in the heating chamber.

6. The kiln gas flow rate adjustment method as described in claim 4, characterized in that, The maximum airflow rate in the cooling box is determined based on the maximum pressure that the kiln body can withstand, and the maximum airflow rate in the cooling box is less than the maximum pressure that the kiln body can withstand.

7. The kiln gas flow rate adjustment method as described in claim 6, characterized in that, The maximum air flow rate of the heating chamber is greater than or equal to the air flow rate that meets the oxygen content standard of the constant temperature chamber when the air flow rates of each section are equal.

8. The kiln gas flow rate adjustment method as described in claim 4, characterized in that, The step of "controlling the air flow rate in the cooling box to gradually increase from the inlet of the cooling box away from the constant temperature box" includes controlling the air flow rate in the cooling box to gradually increase from the inlet of the cooling box away from the constant temperature box, and then gradually decrease.

9. The kiln gas flow rate adjustment method as described in claim 8, characterized in that, The airflow rate inside the cooling box is controlled to suddenly increase to a peak value and then gradually decrease.

10. The kiln gas flow rate adjustment method as described in claim 9, characterized in that, The peak value occurs in the range where the temperature in the cooling box is less than 40°C.

Images