A temperature automatic control system and control method for a kiln production line

Abstract

The present application relates to a kind of temperature automatic control system and control method of kiln production line, it is related to furnace temperature control technical field.Mainly include: according to the temperature of exhaust section, firing section temperature calculation exhaust section and the heat flow flux of firing section, according to firing section temperature and cooling section temperature calculation firing section and the heat flow flux of cooling section;Through the heat flow flux of exhaust section and firing section, calculate the gas flow of exhaust section, through the heat flow flux of firing section and cooling section, calculate the gas flow of firing section;According to the gas flow of exhaust section, calculate the combustion-supporting air flow of exhaust section, and according to the gas flow of firing section, calculate the combustion-supporting air flow of firing section;Through the gas flow of exhaust section, the combustion-supporting air flow of exhaust section adjusts the gas valve opening degree of exhaust section, combustion-supporting air fan frequency converter frequency;Through the gas flow of firing section, the combustion-supporting air flow of firing section adjusts the gas valve opening degree of firing section, combustion-supporting air fan frequency converter frequency.

Description

Technical Field

[0001] This invention relates to the technical field of temperature closed-loop control using electrical quantity feedback, and more specifically to the field of kiln temperature control technology, and more particularly to an automatic temperature control system and control method for a kiln production line. Background Technology

[0002] Existing production lines typically place a limited number of thermocouples or infrared temperature measurement points in key sections of the kiln (such as the preheating zone, firing zone, and cooling zone). First, the temperature sensor collects data in real time. The control system compares the measured value with the set target value and calculates the output signal using the PID (proportional-integral-derivative) formula to adjust the opening of the gas valve or the power of the burner so that the temperature at a single point approaches the set value.

[0003] However, the control logic of the existing control system is an independent loop, lacking coordination between different temperature zones. The kiln car speed is advanced by mechanical push rods at timed intervals, and temperature and motion control are decoupled. Discrete temperature measurement points cannot capture the thermal field distribution of open kilns (especially the rising and stratification of hot air in flat ceiling structures), resulting in local overheating / underheating. Summary of the Invention

[0004] The present invention aims to provide an automatic temperature control system and control method for a kiln production line to overcome the shortcomings of the existing technology. The technical problem to be solved by the present invention is achieved through the following technical solution.

[0005] This invention provides an automatic temperature control system for a kiln production line. The automatic temperature control system includes a kiln body, a temperature sensor, and a temperature control device. The temperature sensor is disposed inside the kiln body and is communicatively connected to the temperature control device. The kiln body includes a flue gas exhaust section, a firing section, and a cooling section. The temperature control device is used to perform the following steps: Temperature sensors installed inside the kiln body are used to obtain the temperatures of the exhaust section, firing section, and cooling section, respectively. The heat flow between the smoke exhaust section and the firing section is calculated based on the smoke exhaust section temperature and the firing section temperature. The heat flow between the firing section and the cooling section is calculated based on the firing section temperature and the cooling section temperature. The gas flow rate in the flue gas section is calculated based on the heat flow between the flue gas section and the firing section, and the gas flow rate in the firing section is calculated based on the heat flow between the firing section and the cooling section. The combustion air flow rate of the exhaust section is calculated based on the gas flow rate of the exhaust section, and the combustion air flow rate of the firing section is calculated based on the gas flow rate of the firing section. The opening degree of the gas valve and the frequency of the combustion fan inverter in the smoke exhaust section are adjusted by the gas flow rate and the combustion air flow rate in the smoke exhaust section; the opening degree of the gas valve and the frequency of the combustion fan inverter in the firing section are adjusted by the gas flow rate and the combustion air flow rate in the firing section.

[0006] In an optional embodiment, the step of acquiring the flue gas section temperature, firing section temperature, and cooling section temperature respectively through temperature sensors installed inside the kiln body includes: Multiple temperature data corresponding to the exhaust section, the firing section and the cooling section are acquired respectively. Multiple temperature sensors are installed at the inlet, outlet and middle of the exhaust section, the firing section and the cooling section. The average values ​​of multiple temperature data corresponding to the exhaust section, the firing section, and the cooling section are calculated to obtain the exhaust section temperature, the firing section temperature, and the cooling section temperature, respectively.

[0007] In an optional embodiment, calculating the heat flux between the flue gas exhaust section and the firing section based on the flue gas exhaust section temperature and the firing section temperature includes: The temperature difference between the exhaust gas section temperature and the inlet temperature of the firing section is calculated to obtain a first temperature difference value, and the temperature difference between the fourth power of the exhaust gas section temperature and the fourth power of the inlet temperature of the firing section is calculated to obtain a second temperature difference value. The heat flow between the flue gas section and the firing section is calculated using the first temperature difference and the second temperature difference.

[0008] In an optional embodiment, calculating the heat flux between the firing section and the cooling section based on the firing section temperature and the cooling section temperature includes: The third temperature difference is obtained by calculating the temperature values ​​of the firing section temperature and the inlet temperature of the cooling section, and the fourth temperature difference is obtained by calculating the fourth power of the firing section temperature and the fourth power of the inlet temperature of the cooling section. The heat flow between the firing section and the cooling section is calculated using the third temperature difference and the fourth temperature difference.

[0009] In an optional embodiment, calculating the gas flow rate of the flue gas section based on the heat flux between the flue gas section and the combustion section includes: The gas flow rate for controlling the exhaust section is calculated based on the setpoint of the exhaust section temperature and the exhaust section temperature. The flow compensation of the exhaust section is calculated by using the set heat flow of the exhaust section and the firing section and the heat flow of the exhaust section and the firing section. The gas flow rate of the exhaust section is obtained by calculating the sum of the controlled gas flow rate of the exhaust section and the flow compensation of the exhaust section.

[0010] In an optional embodiment, calculating the gas flow rate of the firing section based on the heat flux between the firing section and the cooling section includes: The gas flow rate for controlling the firing section is calculated based on the temperature setpoint of the firing section and the temperature of the firing section. The flow compensation of the firing section is calculated by using the set heat flow rate of the firing section and the cooling section and the heat flow rate of the firing section and the cooling section. The boundary compensation of the firing section is calculated using the outlet temperature of the exhaust section and the inlet temperature of the firing section. The gas flow rate of the firing section is obtained by calculating the sum of the control gas flow rate of the firing section, the flow compensation of the firing section, and the boundary compensation of the firing section.

[0011] In an optional embodiment, the step of calculating the combustion air flow rate of the flue gas section based on the gas flow rate of the flue gas section, and calculating the combustion air flow rate of the firing section based on the gas flow rate of the firing section, includes: The first air-fuel ratio is calculated based on the set heat flux of the exhaust section and the firing section, the gas flow rate of the exhaust section, and the temperature standard deviation of the exhaust section; the second air-fuel ratio is calculated based on the set heat flux of the firing section and the cooling section, the combustion air flow rate of the firing section, and the temperature standard deviation of the firing section. The combustion air flow rate of the exhaust section is calculated using the first air-fuel ratio and the gas flow rate of the exhaust section. The combustion air flow rate of the firing section is calculated using the second air-fuel ratio and the gas flow rate of the firing section.

[0012] In an optional embodiment, the first air-fuel ratio is calculated based on the set heat flux of the exhaust section and the firing section, the gas flow rate of the exhaust section, and the temperature standard deviation of the exhaust section; the second air-fuel ratio is calculated based on the set heat flux of the firing section and the cooling section, the combustion air flow rate of the firing section, and the temperature standard deviation of the firing section.

[0013] In an optional embodiment, the gas valve opening and the frequency of the combustion fan inverter in the flue gas section are adjusted by the gas flow rate in the flue gas section and the combustion air flow rate in the flue gas section; the gas valve opening and the frequency of the combustion fan inverter in the firing section are adjusted by the gas flow rate in the firing section and the combustion air flow rate in the firing section.

[0014] This invention provides an automatic temperature control method for a kiln production line. The method is applied to a temperature control device within an automatic temperature control system for a kiln production line, and includes: Temperature sensors installed inside the kiln body are used to obtain the temperatures of the exhaust section, firing section, and cooling section, respectively. The heat flow between the smoke exhaust section and the firing section is calculated based on the smoke exhaust section temperature and the firing section temperature. The heat flow between the firing section and the cooling section is calculated based on the firing section temperature and the cooling section temperature. The gas flow rate in the flue gas section is calculated based on the heat flow between the flue gas section and the firing section, and the gas flow rate in the firing section is calculated based on the heat flow between the firing section and the cooling section. The combustion air flow rate of the exhaust section is calculated based on the gas flow rate of the exhaust section, and the combustion air flow rate of the firing section is calculated based on the gas flow rate of the firing section. The opening degree of the gas valve and the frequency of the combustion fan inverter in the smoke exhaust section are adjusted by the gas flow rate and the combustion air flow rate in the smoke exhaust section; the opening degree of the gas valve and the frequency of the combustion fan inverter in the firing section are adjusted by the gas flow rate and the combustion air flow rate in the firing section.

[0015] The embodiments of the present invention have the following advantages: This invention provides an automatic temperature control system and method for a kiln production line, comprising: a kiln body, a temperature sensor, and a temperature control device. The temperature sensor is installed inside the kiln body, and the temperature sensor and the temperature control device are communicatively connected. The kiln body includes: a flue gas section, a firing section, and a cooling section. The temperature control device performs the following steps: acquiring the flue gas section temperature, firing section temperature, and cooling section temperature respectively corresponding to the flue gas section, firing section, and cooling section through the temperature sensor installed inside the kiln body; calculating the heat flow between the flue gas section and the firing section based on the flue gas section temperature and the firing section temperature; and... The heat flow between the firing and cooling sections is calculated based on the temperatures of the firing and cooling sections. The gas flow rate in the exhaust section is calculated using the heat flow rate between the exhaust and firing sections, and the gas flow rate in the firing section is calculated using the heat flow rate between the firing and cooling sections. The combustion air flow rate in the exhaust section is calculated based on the gas flow rate in the exhaust section, and the combustion air flow rate in the firing section is calculated based on the gas flow rate in the firing section. The opening of the gas valve and the frequency of the combustion air blower in the exhaust section are adjusted based on the gas flow rate and the combustion air flow rate in the exhaust section. Similarly, the opening of the gas valve and the frequency of the combustion air blower in the firing section are adjusted based on the gas flow rate and the combustion air flow rate in the firing section. This application allows for automatic adjustment of the gas valve opening and the combustion air blower frequency based on real-time temperature data, creating a closed-loop energy flow between the exhaust, firing, and cooling sections. This achieves true cross-temperature zone coordinated control, facilitating monitoring and adjustment of temperature control parameters by operators. Attached Figure Description

[0016] Figure 1 This is a flowchart of an automatic temperature control method for a kiln production line provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a temperature control device provided in an embodiment of the present invention. Detailed Implementation

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] This invention provides an automatic temperature control system for a kiln production line. The automatic temperature control system includes a kiln body, a temperature sensor, and a temperature control device. The temperature sensor is disposed inside the kiln body, and the temperature sensor and the temperature control device are communicatively connected. The kiln body includes a flue gas section, a firing section, and a cooling section.

[0019] The kiln body comprises two parts: a steel structure and refractory materials. The kiln's steel frame is constructed from square tubing welded using a rigorous processing technique, with painted steel plates inlaid within the frame. All the kiln's refractory materials are enclosed within the steel structure. Depending on the temperature, different types of refractory materials are used for the kiln lining, including lightweight corundum mullite bricks, lightweight mullite bricks, high-alumina polyaluminum bricks, and lightweight clay bricks. The outer wall of the kiln uses high-strength and heat-insulating aluminosilicate fiberboard.

[0020] In this embodiment, the entire kiln top is a flat suspended ceiling structure. The firing section mainly consists of burners, stirring air curtains, and conversion air curtains. The front section of the firing section only has lower-layer nozzles, with a stirring air hole opposite each nozzle. This creates a strong swirling airflow between the flame and the stirring air inside the kiln, resulting in a more uniform temperature throughout the kiln. Simultaneously, due to the large number of nozzles located close to the kiln head, the temperature difference between the upper and lower parts of the preheating zone can be controlled within 50°C, providing a strong guarantee for shortening the firing cycle and achieving rapid firing. The rear section of the firing section has two rows of burners, facilitating temperature adjustment within the kiln, with the temperature difference controlled within the range of 3±2°C. Two vertical conversion air curtains are installed in the kiln around 1050°C in the firing section. Cold air from outside the kiln is drawn in by a combustion fan and then injected into the kiln through small vertical holes in the side walls, achieving an atmosphere conversion from an oxidizing flame to a reducing flame within the kiln.

[0021] The cooling section consists of a rapid cooling section, a slow cooling section, and a tail cooling section. The rapid cooling section has two vertical air curtains and two rows of horizontal cooling holes on both sides of the kiln walls and the kiln roof, drawing in cold air from outside the kiln to rapidly cool the products according to process requirements. The slow cooling section only has a few exhaust hoods on the kiln roof and side walls to draw the hot air from the rapid cooling and tail cooling sections out of the kiln in a balanced manner, allowing the products to cool slowly. The kiln tail is the tail cooling section of the cooling section. Cold air from outside the kiln is blown into the kiln through a tail cooling fan and a cooling hood, rapidly cooling the products before they exit the kiln. The product exit temperature can be below 70℃.

[0022] The kiln car frame is welded from structural steel. The kiln car's perimeter lining is constructed of cordierite-mullite composite bricks resistant to rapid heating and cooling and fracture, with folded cotton blocks used to seal the center. The kiln car lining surface consists of a 20mm zirconium-containing fiber blanket and two 40mm high-alumina blankets. This structure achieves energy conservation and consumption reduction. Because the kiln is open-flame fired, multiple layers of shelf supports can be installed on the car surface for direct firing of the products. These supports are made of silicon carbide material with good thermal conductivity, high refractoriness, good resistance to rapid heating and cooling, and long service life. The kiln car's connection to the kiln wall is a single curved seal. To prevent excessively high temperatures under the car, a 16-meter high-temperature section is provided with under-car ventilation, introducing a small amount of cool air to lower the wheel temperature. The kiln car wheels are fixed to the kiln car axle, a unique design that extends bearing life and minimizes the gap between the wheels and the track.

[0023] like Figure 2 As shown, this embodiment provides an automatic temperature control method for a kiln production line. This method is applied to a temperature control device in the automatic temperature control system of the kiln production line. The temperature control device is used to perform the following steps: S101, the temperature of the flue gas section, the temperature of the firing section, and the temperature of the cooling section are obtained by a temperature sensor installed inside the kiln body.

[0024] The primary function of the flue gas exhaust section is to preheat the green body using the residual heat from the flue gas in the firing section, while simultaneously venting waste gas. The firing section is used to vitrify / sinter the green body through natural gas combustion. The cooling section controls the cooling rate to prevent product cracking. In this embodiment, the flue gas exhaust section, firing section, and cooling section are arranged sequentially along the longitudinal direction of the kiln (i.e., the direction of kiln car movement). The kiln car enters from the kiln head, first passing through the flue gas exhaust section (also known as the preheating section), then entering the firing section, and finally entering the cooling section, exiting from the kiln tail.

[0025] In order to automatically adjust the opening of the gas valve and the frequency of the combustion fan inverter according to the temperature, this embodiment requires temperature sensors to be placed at different locations in the kiln body to obtain the temperature distribution of each section. In this embodiment, temperature sensors can be installed at the inlet, outlet, and middle of the flue gas section, the firing section, and the cooling section to obtain the corresponding temperatures of the flue gas section, the firing section, and the cooling section, respectively.

[0026] For example, in this embodiment, a temperature sensor (measuring flue gas temperature) can be arranged every 2 meters along the kiln length, 0.3 meters below the top of the flue gas section. The top temperature sensor monitors the temperature distribution of the hot flue gas. Since the hot gas rises, the top temperature is higher, which can reflect the stratification of the flue gas. A temperature sensor (measuring the temperature near the billet) can be arranged every 2 meters on the side wall of the flue gas section near the kiln car platform (at a height of about 0.3 meters). The side wall temperature sensor monitors the actual heating temperature of the billet to avoid uneven heating of the billet. Infrared thermometers are installed at the inlet and outlet of the flue gas section to monitor the surface temperature of the billet. The inlet and outlet infrared thermometers are used to monitor the temperature of the billet entering and leaving the flue gas section, calculate the heating rate, and prevent cracking caused by excessive heating.

[0027] For example, distributed temperature sensors are embedded in the flat ceiling at the top of the firing section, with one temperature measuring point every 0.5m (monitoring the top temperature field). The distributed temperature sensors can continuously monitor the temperature distribution at the top of the entire firing section. Since the flat ceiling structure is prone to thermal stratification, dense monitoring is required by using distributed temperature sensors. Two-color infrared temperature sensors are installed at the middle position (about 0.5H) on both sides of the kiln wall in the height direction, one every 1m (monitoring the surface temperature of the product). The two-color infrared temperature sensors are not easily affected by flue gas and accurately obtain the surface temperature of the product to ensure firing quality. Thermocouples are installed on both sides of the kiln car track at a height of 0.2m, one every 1m (monitoring the bottom temperature). Thermocouples near the track monitor the heat dissipation between the kiln car and the kiln body to prevent the bottom temperature from being too low.

[0028] For example, an infrared array temperature sensor is installed at the top of the cooling section, with one temperature measurement point per 1m × 1m grid (monitoring the surface temperature field of the product). The cooling section requires rapid and uniform cooling, and the infrared array monitors the surface temperature field in real time to prevent uneven cooling that could lead to deformation. Thermocouples are installed on the side walls of the cooling section at heights of 0.5H and 0.2H, arranged in groups of 2m (monitoring temperatures at different heights). Thermocouples at different heights monitor the temperature gradient to prevent excessively rapid cooling that could cause the product to crack. At the end of the cooling section, contact thermocouples measure the core temperature of the product, ensuring that the product is cooled to a safe temperature.

[0029] In one optional embodiment provided in this application, the step of obtaining the exhaust section temperature, firing section temperature, and cooling section temperature corresponding to the exhaust section, firing section, and cooling section respectively through temperature sensors installed inside the kiln body includes: obtaining multiple temperature data corresponding to the exhaust section, firing section, and cooling section respectively, wherein multiple temperature sensors are installed at the inlet, outlet, and middle of the exhaust section, firing section, and cooling section; and averaging the multiple temperature data corresponding to the exhaust section, firing section temperature, and cooling section respectively to obtain the exhaust section temperature, firing section temperature, and cooling section temperature respectively.

[0030] Specifically, the temperatures of the exhaust section, firing section, and cooling section can be calculated using the following formulas:

[0031] Where j is the temperature zone number (1: exhaust section, 2: firing section, 3: cooling section). The value of j, 1-3, represents the temperature of the flue gas section, the temperature of the firing section, and the temperature of the cooling section, respectively. Let j be the number of temperature measuring points in temperature zone j. Let be the temperature of the i-th temperature measuring point in temperature zone j.

[0032] S102, calculate the heat flow between the smoke exhaust section and the firing section based on the temperature of the smoke exhaust section and the temperature of the firing section, and calculate the heat flow between the firing section and the cooling section based on the temperature of the firing section and the temperature of the cooling section.

[0033] Heat flux refers to the heat energy passing through a unit area per unit time, and its unit is W / m².

[0034] Specifically, the step of calculating the heat flow between the smoke exhaust section and the firing section based on the smoke exhaust section temperature and the firing section temperature includes: calculating a first temperature difference by calculating the temperature values ​​of the smoke exhaust section temperature and the inlet temperature of the firing section, and a second temperature difference by calculating the fourth power of the smoke exhaust section temperature and the fourth power of the inlet temperature of the firing section; and calculating the heat flow between the smoke exhaust section and the firing section using the first temperature difference and the second temperature difference.

[0035] At the interface between adjacent temperature zones in a kiln (e.g., between the firing section and the cooling section), due to the temperature difference, heat flux is mainly transferred through heat convection and heat radiation, since there is usually no solid medium directly connecting the two temperature zones (i.e., conduction can be ignored). Therefore, in this embodiment, heat flux can be calculated using the sum of heat convection and heat radiation, as shown by... Calculate the heat flow between the flue gas section and the firing section.

[0036] In this embodiment, through the formula The first temperature difference is obtained by calculating the temperature values ​​of the exhaust section temperature and the inlet temperature of the firing section, and then using the formula... The second temperature difference is obtained by calculating the fourth power of the flue gas temperature and the fourth power of the inlet temperature of the firing section. Then, according to the formula... Calculate the heat flow between the flue gas section and the firing section.

[0037] in, This represents the heat flow between the exhaust section and the firing section. Temperature of the exhaust section, The inlet temperature of the firing section. The fourth power of the flue gas exhaust temperature. This is the fourth power of the inlet temperature of the firing section. The convective heat transfer coefficient (W / (m²·K)) is the coefficient for the exhaust section and the firing section. Let be the cross-sectional area of ​​the interface between the flue gas section and the firing section. The Stefan-Boltzmann constant is 5.67 × 10⁻⁶. -8 W / (m²·K 4 )), The interfacial emissivity between the smoke exhaust section and the firing section is 0.8~0.9. Specifically, the calculation of the heat flow between the firing section and the cooling section based on the firing section temperature and the cooling section temperature includes: calculating the temperature values ​​of the firing section temperature and the inlet temperature of the cooling section to obtain a third temperature difference, and the temperature values ​​of the fourth power of the firing section temperature and the fourth power of the inlet temperature of the cooling section to obtain a fourth temperature difference; and calculating the heat flow between the firing section and the cooling section using the third temperature difference and the fourth temperature difference.

[0038] In this embodiment, through the formula The third temperature difference is obtained by calculating the temperature values ​​of the firing section temperature and the inlet temperature of the cooling section, using the formula... The fourth temperature difference is obtained by calculating the fourth power of the firing section temperature and the fourth power of the cooling section inlet temperature. Then, according to the formula... Calculate the heat flow between the firing section and the cooling section.

[0039] in, This refers to the heat flow between the firing section and the cooling section. The firing temperature is the temperature of the firing section. This refers to the inlet temperature of the cooling section. The fourth power of the firing temperature. This is the fourth power of the inlet temperature of the cooling section. The convective heat transfer coefficients for the firing and cooling sections are determined by the kiln structure and airflow velocity. This represents the cross-sectional area of ​​the interface between the firing section and the cooling section. The emissivity is the interfacial emissivity between the firing section and the cooling section.

[0040] S103, calculate the gas flow rate of the flue gas section based on the heat flow between the flue gas section and the firing section, and calculate the gas flow rate of the firing section based on the heat flow between the firing section and the cooling section.

[0041] Specifically, the step of calculating the gas flow rate of the exhaust section based on the heat flux between the exhaust section and the firing section includes: calculating the controlled gas flow rate of the exhaust section based on the set temperature of the exhaust section and the temperature of the exhaust section; calculating the exhaust section flow rate compensation based on the set heat flux between the exhaust section and the firing section and the heat flux between the exhaust section and the firing section; and calculating the sum of the controlled gas flow rate of the exhaust section and the exhaust section flow rate compensation to obtain the gas flow rate of the exhaust section.

[0042] In this embodiment, the gas flow in the exhaust section can be calculated using the following formula.

[0043] in, The gas flow rate in the exhaust section. To control the gas flow in the exhaust section, For smoke exhaust section flow compensation, This is the temperature setpoint for the smoke exhaust section. Temperature of the exhaust section, The set heat flow rate for the exhaust section and the firing section. This refers to the heat flow between the exhaust section and the firing section. This is the proportional gain coefficient for the smoke exhaust section (unit: m³ / (h·℃)). This is the proportional gain coefficient for the smoke exhaust section (unit: m³ / (h·kW)).

[0044] Specifically, the calculation of the gas flow rate in the firing section based on the heat flux between the firing section and the cooling section includes: calculating the control gas flow rate in the firing section based on the temperature setpoint of the firing section and the firing section temperature; calculating the flow rate compensation in the firing section based on the set heat flux between the firing section and the cooling section and the heat flux between the firing section and the cooling section; calculating the boundary compensation in the firing section based on the outlet temperature of the flue gas section and the inlet temperature of the firing section; and calculating the sum of the control gas flow rate in the firing section, the flow rate compensation in the firing section, and the boundary compensation in the firing section to obtain the gas flow rate in the firing section.

[0045] In this embodiment, the gas flow rate in the combustion section can be calculated using the following formula:

[0046] in, for, To control the gas flow rate in the combustion section, For flow compensation in the firing section, For the boundary compensation of the firing section, This is the temperature setpoint for the firing section. The firing temperature is the temperature of the firing section. The set heat flow rate for the firing section and the cooling section. This refers to the heat flow between the firing section and the cooling section. The outlet temperature of the smoke exhaust section. The inlet temperature of the firing section. The proportional gain coefficient for the firing section (in m³ / (h·℃)) is: This is the proportional gain coefficient of the firing section (unit: m³ / (h·kW)). The boundary temperature difference compensation coefficient is (m³ / (h·℃)).

[0047] S104, calculate the combustion air flow rate of the exhaust section based on the gas flow rate of the exhaust section, and calculate the combustion air flow rate of the firing section based on the gas flow rate of the firing section.

[0048] In one optional embodiment provided in this application, the step of calculating the combustion air flow rate of the flue gas section based on the gas flow rate of the flue gas section, and calculating the combustion air flow rate of the firing section based on the gas flow rate of the firing section, includes: S1041, calculate the first air-fuel ratio based on the set heat flux of the exhaust section and the firing section, the gas flow rate of the exhaust section, and the temperature standard deviation of the exhaust section; calculate the second air-fuel ratio based on the set heat flux of the firing section and the cooling section, the combustion air flow rate of the firing section, and the temperature standard deviation of the firing section.

[0049] Specifically, the air-fuel ratio is dynamically adjusted based on the heat load and temperature uniformity of the temperature zone to improve combustion efficiency. In this embodiment, the air-fuel ratio can be calculated using the following formula:

[0050] in, The air-fuel ratio is represented by j, where j is either 1 or 2. Represents the smoke exhaust section. Represents the firing stage, As the baseline air-fuel ratio, The gas flow rate in the exhaust section. To increase the combustion air flow rate in the firing section, Let j be the set heat flux from j+1. The heat flux coefficient is... Let j be the standard deviation of the temperature in segment j. This is the standard deviation threshold (e.g., 5℃).

[0051] S1042, calculate the combustion air flow rate of the exhaust section using the first air-fuel ratio and the gas flow rate of the exhaust section.

[0052] S1043, calculates the combustion air flow rate of the combustion section using the second air-fuel ratio and the gas flow rate of the combustion section.

[0053] In this embodiment, the combustion air flow rate is calculated using the following formula:

[0054] in, To increase the airflow, Air-fuel ratio, This represents the theoretical air-fuel ratio by volume (10.5 m³ air / m³ fuel for natural gas). Where, when j=1, To increase the combustion airflow in the smoke exhaust section, The first air-fuel ratio, This represents the gas flow rate in the exhaust section; when j=2, To increase the combustion airflow in the smoke exhaust section, The second air-fuel ratio, The combustion air flow rate for the firing section.

[0055] S105 adjusts the opening of the gas valve and the frequency of the combustion fan inverter in the smoke exhaust section by adjusting the gas flow rate and the combustion air flow rate in the smoke exhaust section; and adjusts the opening of the gas valve and the frequency of the combustion fan inverter in the firing section by adjusting the gas flow rate and the combustion air flow rate in the firing section.

[0056] In one optional embodiment provided in this application, the step of adjusting the gas valve opening and the frequency of the combustion fan inverter in the flue gas section by the gas flow rate in the flue gas section and the combustion air flow rate in the flue gas section; and adjusting the gas valve opening and the frequency of the combustion fan inverter in the firing section by the gas flow rate in the firing section and the combustion air flow rate in the firing section, includes: According to the formula Calculate the opening degree of the gas regulating valve; According to the formula Calculate the frequency of the combustion fan inverter; in, For the opening degree of the gas regulating valve in segment j, The flow characteristic curve of the gas valve is shown. Let J be the gas flow rate of segment j; The frequency of the combustion fan inverter in segment j is... This is the flow characteristic curve of the fan. For the combustion air flow rate of the j-th segment, Represents the smoke exhaust section. Represents the firing stage.

[0057] In an optional embodiment, after step S105, this embodiment can adjust the kiln car speed based on the deviation between the firing section outlet temperature and the set value. When the temperature difference between the firing section outlet and the cooling section inlet exceeds the normal range, the kiln car speed is adjusted to change the residence time of the product in the firing section, thereby reducing the temperature difference and ensuring the firing quality of the product. The kiln car speed update formula is:

[0058] in, For the updated kiln car speed (m / s). The kiln car speed (m / s) before the update. The outlet temperature of the firing section. Set the temperature for the firing section. This is the critical temperature difference (e.g., 15℃), a safety threshold set by the process. When the boundary temperature difference exceeds this value, the kiln car speed needs to be significantly adjusted. K The gain for speed adjustment (0~1) is a coefficient that determines the magnitude of speed adjustment and is obtained through experimental calibration.

[0059] This is a sign function for the rate of change of the boundary temperature difference. This function returns +1 or -1 depending on the trend of the temperature difference. If the temperature difference is widening (i.e., ...), the sign function will return -1. If the temperature difference is >0, then return +1. If the temperature difference is decreasing (i.e., ... If <0), then return -1.

[0060] Furthermore, after adjusting the kiln car speed, it is determined whether the target conditions are met. If not, no adjustment is needed; otherwise, the process jumps to step S101 to continue sequential execution until the target conditions are met. The target conditions can be that the average temperature of each temperature zone deviates from the set value by less than ±5℃, and the interfacial heat flux deviates from the set value by less than ±10%. , Therefore, this embodiment achieves coordinated control of temperature zones through the above steps, dynamically linking adjacent temperature zones by interfacial heat flux, thus solving the problem of independent loops. This effectively addresses the temperature inconsistency caused by the independent operation of each temperature zone in traditional control systems.

[0061] This embodiment provides an automatic temperature control method for a kiln production line. The method uses temperature sensors installed inside the kiln to acquire the temperatures of the exhaust section, firing section, and cooling section, respectively. It calculates the heat flow between the exhaust section and firing section based on the exhaust and firing section temperatures, and the heat flow between the firing and cooling sections based on the firing and cooling section temperatures. It also calculates the gas flow rate in the exhaust section and the firing section based on the heat flow rate between the exhaust and firing sections. Furthermore, it calculates the combustion air flow rate in the exhaust section and the firing section based on the gas flow rate in the firing section. Finally, it adjusts the gas valve opening and combustion air frequency of the exhaust fan in the exhaust section based on the gas flow rate and combustion air flow rate in the firing section. This application allows for the automatic adjustment of the gas valve opening and the frequency of the combustion fan inverter based on real-time temperature data, enabling the exhaust section, combustion section, and cooling section to form a closed loop of energy flow and achieving true cross-temperature zone coordinated control. This facilitates operators in monitoring and adjusting temperature control parameters. It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0062] In one embodiment, a temperature control device is provided. For example... Figure 2 As shown, the functional modules of this temperature control device are described in detail below: The acquisition module 21 is used to acquire the exhaust section temperature, firing section temperature and cooling section temperature respectively of the exhaust section, firing section and cooling section through a temperature sensor installed inside the kiln body; The first calculation module 22 is used to calculate the heat flow between the smoke exhaust section and the firing section based on the temperature of the smoke exhaust section and the temperature of the firing section, and to calculate the heat flow between the firing section and the cooling section based on the temperature of the firing section and the temperature of the cooling section. The second calculation module 23 is used to calculate the gas flow rate of the flue gas section based on the heat flow between the flue gas section and the firing section, and to calculate the gas flow rate of the firing section based on the heat flow between the firing section and the cooling section; The third calculation module 24 is used to calculate the combustion air flow rate of the flue gas section based on the gas flow rate of the flue gas section, and to calculate the combustion air flow rate of the firing section based on the gas flow rate of the firing section. The adjustment module 25 is used to adjust the opening degree of the gas valve and the frequency of the combustion fan inverter in the flue gas section by the gas flow rate in the flue gas section and the combustion air flow rate in the flue gas section; and to adjust the opening degree of the gas valve and the frequency of the combustion fan inverter in the firing section by the gas flow rate in the firing section and the combustion air flow rate in the firing section.

[0063] In an optional embodiment, the acquisition module 21 is specifically used for: Multiple temperature data corresponding to the exhaust section, the firing section and the cooling section are acquired respectively. Multiple temperature sensors are installed at the inlet, outlet and middle of the exhaust section, the firing section and the cooling section. The average values ​​of multiple temperature data corresponding to the exhaust section, the firing section, and the cooling section are calculated to obtain the exhaust section temperature, the firing section temperature, and the cooling section temperature, respectively.

[0064] In an optional embodiment, the first computing module 22 is specifically used for: The temperature difference between the exhaust gas section temperature and the inlet temperature of the firing section is calculated to obtain a first temperature difference value, and the temperature difference between the fourth power of the exhaust gas section temperature and the fourth power of the inlet temperature of the firing section is calculated to obtain a second temperature difference value. The heat flow between the flue gas section and the firing section is calculated using the first temperature difference and the second temperature difference.

[0065] In an optional embodiment, the first computing module 22 is specifically used for: The third temperature difference is obtained by calculating the temperature values ​​of the firing section temperature and the inlet temperature of the cooling section, and the fourth temperature difference is obtained by calculating the fourth power of the firing section temperature and the fourth power of the inlet temperature of the cooling section. The heat flow between the firing section and the cooling section is calculated using the third temperature difference and the fourth temperature difference.

[0066] In an optional embodiment, the second computing module 23 is specifically used for: The gas flow rate for controlling the exhaust section is calculated based on the setpoint of the exhaust section temperature and the exhaust section temperature. The flow compensation of the exhaust section is calculated by using the set heat flow of the exhaust section and the firing section and the heat flow of the exhaust section and the firing section. The gas flow rate of the exhaust section is obtained by calculating the sum of the controlled gas flow rate of the exhaust section and the flow compensation of the exhaust section.

[0067] In an optional embodiment, the second computing module 23 is specifically used for: The gas flow rate for controlling the firing section is calculated based on the temperature setpoint of the firing section and the temperature of the firing section. The flow compensation of the firing section is calculated by using the set heat flow rate of the firing section and the cooling section and the heat flow rate of the firing section and the cooling section. The boundary compensation of the firing section is calculated using the outlet temperature of the exhaust section and the inlet temperature of the firing section. The gas flow rate of the firing section is obtained by calculating the sum of the control gas flow rate of the firing section, the flow compensation of the firing section, and the boundary compensation of the firing section.

[0068] In an optional embodiment, the third computing module 24 is specifically used for: The first air-fuel ratio is calculated based on the set heat flux of the exhaust section and the firing section, the gas flow rate of the exhaust section, and the temperature standard deviation of the exhaust section; the second air-fuel ratio is calculated based on the set heat flux of the firing section and the cooling section, the combustion air flow rate of the firing section, and the temperature standard deviation of the firing section. The combustion air flow rate of the exhaust section is calculated using the first air-fuel ratio and the gas flow rate of the exhaust section. The combustion air flow rate of the firing section is calculated using the second air-fuel ratio and the gas flow rate of the firing section.

[0069] In an optional embodiment, the third calculation module 24 is specifically used to calculate the air-fuel ratio using the following formula:

[0070] in, The air-fuel ratio is represented by j, where j is either 1 or 2. Represents the smoke exhaust section. Represents the firing stage, As the baseline air-fuel ratio, The gas flow rate in the exhaust section. To increase the combustion air flow rate in the firing section, Let j be the set heat flux from j+1. The heat flux coefficient is... Let j be the standard deviation of the temperature in segment j. This is the standard deviation threshold.

[0071] In an optional embodiment, the adjustment module 25 is specifically used for: According to the formula Calculate the opening degree of the gas regulating valve; According to the formula Calculate the frequency of the combustion fan inverter; in, For the opening degree of the gas regulating valve in segment j, The flow characteristic curve of the gas valve is shown. Let J be the gas flow rate of segment j; The frequency of the combustion fan inverter in segment j is... This is the flow characteristic curve of the fan. For the combustion air flow rate of the j-th segment, Represents the smoke exhaust section. Represents the firing stage.

[0072] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0073] Specific limitations regarding the temperature control system can be found in the above section on the automatic temperature control method for kiln production lines, and will not be repeated here. Each module in the aforementioned equipment can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the computer device's memory as software, so that the processor can call and execute the corresponding operations of each module.

[0074] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the system can be divided into different functional units or modules to complete all or part of the functions described above.

[0075] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. An automatic temperature control system for a kiln production line, characterized in that, The automatic temperature control system includes a kiln body, a temperature sensor, and a temperature control device. The temperature sensor is located inside the kiln body and is communicatively connected to the temperature control device. The kiln body includes a flue gas exhaust section, a firing section, and a cooling section. The temperature control device is used to perform the following steps: Temperature sensors installed inside the kiln body are used to obtain the temperatures of the exhaust section, firing section, and cooling section, respectively. The heat flow between the smoke exhaust section and the firing section is calculated based on the smoke exhaust section temperature and the firing section temperature. The heat flow between the firing section and the cooling section is calculated based on the firing section temperature and the cooling section temperature. The gas flow rate in the flue gas section is calculated based on the heat flow between the flue gas section and the firing section, and the gas flow rate in the firing section is calculated based on the heat flow between the firing section and the cooling section. The combustion air flow rate of the exhaust section is calculated based on the gas flow rate of the exhaust section, and the combustion air flow rate of the firing section is calculated based on the gas flow rate of the firing section; the calculation of the combustion air flow rate of the exhaust section and the combustion air flow rate of the firing section based on the gas flow rate of the exhaust section includes: calculating a first air-fuel ratio based on the set heat flux of the exhaust section and the firing section, the gas flow rate of the exhaust section, and the temperature standard deviation of the exhaust section; calculating a second air-fuel ratio based on the set heat flux of the firing section and the cooling section, the combustion air flow rate of the firing section, and the temperature standard deviation of the firing section; calculating the combustion air flow rate of the exhaust section using the first air-fuel ratio and the gas flow rate of the exhaust section; and calculating the combustion air flow rate of the firing section using the second air-fuel ratio and the gas flow rate of the firing section. The opening degree of the gas valve and the frequency of the combustion fan inverter in the smoke exhaust section are adjusted by the gas flow rate and the combustion air flow rate in the smoke exhaust section; the opening degree of the gas valve and the frequency of the combustion fan inverter in the firing section are adjusted by the gas flow rate and the combustion air flow rate in the firing section.

2. The system according to claim 1, characterized in that, The method of obtaining the flue gas section temperature, firing section temperature, and cooling section temperature respectively through temperature sensors installed inside the kiln body includes: Multiple temperature data corresponding to the exhaust section, the firing section and the cooling section are acquired respectively. Multiple temperature sensors are installed at the inlet, outlet and middle of the exhaust section, the firing section and the cooling section. The average values ​​of multiple temperature data corresponding to the exhaust section, the firing section, and the cooling section are calculated to obtain the exhaust section temperature, the firing section temperature, and the cooling section temperature, respectively.

3. The system according to claim 2, characterized in that, The calculation of the heat flow between the flue gas section and the firing section based on the flue gas section temperature and the firing section temperature includes: The temperature difference between the exhaust gas section temperature and the inlet temperature of the firing section is calculated to obtain a first temperature difference value, and the temperature difference between the fourth power of the exhaust gas section temperature and the fourth power of the inlet temperature of the firing section is calculated to obtain a second temperature difference value. The heat flow between the flue gas section and the firing section is calculated using the first temperature difference and the second temperature difference.

4. The system according to claim 2, characterized in that, The calculation of the heat flow between the firing section and the cooling section based on the firing section temperature and the cooling section temperature includes: The third temperature difference is obtained by calculating the temperature values ​​of the firing section temperature and the inlet temperature of the cooling section, and the fourth temperature difference is obtained by calculating the fourth power of the firing section temperature and the fourth power of the inlet temperature of the cooling section. The heat flow between the firing section and the cooling section is calculated using the third temperature difference and the fourth temperature difference.

5. The system according to claim 3, characterized in that, The calculation of the gas flow rate in the exhaust section based on the heat flow between the exhaust section and the combustion section includes: The gas flow rate for controlling the exhaust section is calculated based on the setpoint of the exhaust section temperature and the exhaust section temperature. The flow compensation of the exhaust section is calculated by using the set heat flow of the exhaust section and the firing section and the heat flow of the exhaust section and the firing section. The gas flow rate of the exhaust section is obtained by calculating the sum of the controlled gas flow rate of the exhaust section and the flow compensation of the exhaust section.

6. The system according to claim 4, characterized in that, The calculation of the gas flow rate in the firing section based on the heat flow between the firing section and the cooling section includes: The gas flow rate for controlling the firing section is calculated based on the temperature setpoint of the firing section and the temperature of the firing section. The flow compensation of the firing section is calculated by using the set heat flow rate of the firing section and the cooling section and the heat flow rate of the firing section and the cooling section. The boundary compensation of the firing section is calculated using the outlet temperature of the exhaust section and the inlet temperature of the firing section. The gas flow rate of the firing section is obtained by calculating the sum of the control gas flow rate of the firing section, the flow compensation of the firing section, and the boundary compensation of the firing section.

7. A method for automatic temperature control in a kiln production line, characterized in that, The method is applied to a temperature control device in an automatic temperature control system for a kiln production line according to any one of claims 1-6, and the method includes: Temperature sensors installed inside the kiln body are used to obtain the temperatures of the exhaust section, firing section, and cooling section, respectively. The heat flow between the smoke exhaust section and the firing section is calculated based on the smoke exhaust section temperature and the firing section temperature. The heat flow between the firing section and the cooling section is calculated based on the firing section temperature and the cooling section temperature. The gas flow rate in the flue gas section is calculated based on the heat flow between the flue gas section and the firing section, and the gas flow rate in the firing section is calculated based on the heat flow between the firing section and the cooling section. The combustion air flow rate of the exhaust section is calculated based on the gas flow rate of the exhaust section, and the combustion air flow rate of the firing section is calculated based on the gas flow rate of the firing section; the calculation of the combustion air flow rate of the exhaust section and the combustion air flow rate of the firing section based on the gas flow rate of the exhaust section includes: calculating a first air-fuel ratio based on the set heat flux of the exhaust section and the firing section, the gas flow rate of the exhaust section, and the temperature standard deviation of the exhaust section; calculating a second air-fuel ratio based on the set heat flux of the firing section and the cooling section, the combustion air flow rate of the firing section, and the temperature standard deviation of the firing section; calculating the combustion air flow rate of the exhaust section using the first air-fuel ratio and the gas flow rate of the exhaust section; and calculating the combustion air flow rate of the firing section using the second air-fuel ratio and the gas flow rate of the firing section. The opening degree of the gas valve and the frequency of the combustion fan inverter in the smoke exhaust section are adjusted by the gas flow rate and the combustion air flow rate in the smoke exhaust section; the opening degree of the gas valve and the frequency of the combustion fan inverter in the firing section are adjusted by the gas flow rate and the combustion air flow rate in the firing section.

Images