Method and device for precisely regulating internal temperature of energy-saving rotary kiln

Abstract

The present application relates to rotary kiln temperature control technical field, specifically to a kind of internal temperature accurate regulation and control method and device of energy-saving rotary kiln.Construct regional heat compensation system, for the heat in secondary storage exhaust gas, and in different regions of rotary kiln using suitable heat flow speed to realize heat compensation and temperature control.Due to unable to directly measure material temperature, the present application is based on gas temperature value analysis heat exchange between airflow and material, obtain material temperature, and further predict the gas predicted temperature of each monitoring point at future time.According to heat transfer formula, obtain the gas compensation temperature under different heat compensation power, and by comparing the gas predicted temperature at future time with gas compensation temperature, determine the heat compensation deviation of each heat compensation power.The selection of optimal heat compensation power makes that regional heat compensation system can accurately compensate the gas temperature in rotary kiln, realizes temperature accurate control, reduces heat energy loss, and improves energy utilization rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rotary kiln temperature control, in particular to an internal temperature accurate regulation method and device of an energy-saving rotary kiln. BACKGROUND

[0002] As a kind of widely used in cement, metallurgy, chemical industry and other fields of thermal equipment, mainly used for calcination, decomposition and sintering of materials, its internal temperature control plays a crucial role in improving product quality, reducing energy consumption and prolonging equipment life. With the improvement of energy saving and environmental protection requirements, through optimizing heat utilization, introducing intelligent control system, energy consumption reduction, process stability improvement and environmental impact minimization can be realized, which provides technical support for green development of cement industry.

[0003] The existing rotary kiln temperature regulation method usually performs rough adjustment based on the deviation between the actual temperature obtained by the sensor and the preset temperature. However, since the temperature obtained by the sensor is mostly gas temperature, it cannot directly collect the temperature of the flowing material inside the rotary kiln. In addition, due to the differences in material state, heat exchange and heat transfer mode in different areas of the kiln body (cooling zone, sintering zone, preheating zone), the temperature distribution is uneven, which further increases the difficulty of temperature control. If only the deviation between the actual temperature and the preset temperature is used for rough adjustment, it is easy to affect the sintering quality of the material. SUMMARY

[0004] In order to solve the technical problem that the temperature obtained by the sensor is mostly gas temperature, which cannot directly collect the temperature of the flowing material inside the rotary kiln, and in different areas of the kiln body (cooling zone, sintering zone, preheating zone), due to the differences in material state, heat exchange and heat transfer mode, the temperature distribution is uneven, which further increases the difficulty of temperature control, and if only the deviation between the actual temperature and the preset temperature is used for rough adjustment, it is easy to affect the sintering quality of the material, the purpose of the present application is to provide an internal temperature accurate regulation method and device of an energy-saving rotary kiln, the technical scheme adopted is as follows:

[0005] An internal temperature accurate regulation method of an energy-saving rotary kiln, including a regional heat compensation system, the kiln body is divided into three regions, which are cooling zone, sintering zone and preheating zone, the method comprises:

[0006] At each monitoring point, the gas temperature value inside the rotary kiln at the current time and the pipe temperature of the outer wall of the rotary kiln body are obtained, the monitoring points are uniformly distributed in a straight line in each region of the kiln body; the raw material temperature of the inlet is obtained;

[0007] analyze the gas heat exchange condition based on the change of the gas temperature value between the monitoring points and the positional relationship, and calculate the material temperature at the position of each monitoring point at the current time instant in combination with the material heat exchange condition of the material in the rotary kiln and the material flow time;

[0008] Under different thermal compensation powers, the gas compensation temperature at the position of each monitoring point after thermal compensation is predicted based on a heat transfer formula under each thermal compensation power;

[0009] Under each thermal compensation power, the difference between the gas compensation temperature at the position of each monitoring point and the predicted gas temperature at the future time instant is analyzed to obtain the thermal compensation deviation corresponding to each thermal compensation power; and the optimal thermal compensation power is determined based on the thermal compensation deviation to perform thermal compensation on the gas temperature in the rotary kiln.

[0010] Further, the method for obtaining the material temperature comprises:

[0011] In each region, the gas heat exchange rate per unit time is obtained according to the Euclidean distance between the monitoring points and the gas temperature value, and the formula model of the gas heat exchange rate comprises:

[0012]

[0013] wherein RT1 represents the gas heat exchange rate between any two monitoring points; T represents the gas temperature value of the monitoring point farthest from the charging port among the any two monitoring points; T1 represents the gas temperature value of the monitoring point closest to the charging port among the any two monitoring points; and L represents the Euclidean distance between the any two monitoring points.

[0014] The position of the monitoring point at the center of the firing zone of the kiln body is taken as a comparison position, the gas temperature value at the comparison position is considered to be the same as the material temperature, and the gas temperature value at the comparison position at the current time instant is taken as a comparison temperature;

[0015] Based on the comparison temperature and the raw material temperature of the charging port, a first material heat exchange rate is obtained, and the formula model of the first material heat exchange rate comprises:

[0016] RT' = h x A x (T' - T")

[0017] wherein RT' represents the first material heat exchange rate; h represents a convective heat transfer coefficient; A represents a heat transfer area; T' represents the raw material temperature of the charging port; T" represents the comparison temperature; and h x A represents a heat flow coefficient, denoted as k.

[0018] According to the gas heat exchange rate between the comparison position and the position of the monitoring point closest to the feeding port, the first material heat exchange rate, and the material flow turnover time between the comparison position and the position of the monitoring point closest to the feeding port, a heat flux coefficient is obtained;

[0019] According to the gas heat exchange rate between the comparison position and the position of any one monitoring point, the heat flux coefficient, and the comparison temperature, the material temperature at the position of the monitoring point at the current time is calculated, and the formula model of the material temperature includes:

[0020]

[0021] Wherein, WR represents the material temperature at the position of any one monitoring point at the current time; T" represents the comparison temperature; RT3 represents the gas heat exchange rate between the comparison position and the position of any one monitoring point; and k represents the heat flux coefficient.

[0022] Further, the formula model of the heat flux coefficient includes:

[0023]

[0024] Wherein, k represents the heat flux coefficient; RT2 represents the gas heat exchange rate between the comparison position and the position of the monitoring point closest to the feeding port per unit time; t represents the material flow turnover time between the comparison position and the position of the monitoring point closest to the feeding port; T' represents the raw material temperature of the feeding port; and T" represents the comparison temperature.

[0025] Further, the method for obtaining the gas prediction temperature includes:

[0026] The difference between the future time and the current time is taken as a time interval, the monitoring point whose material flow turnover time between the monitoring point and the feeding port is less than the time interval is taken as a monitoring point to be measured, and the average of the material temperatures at the positions of all the monitoring points to be measured at the current time is taken as an initial temperature value at each monitoring point;

[0027] According to the difference between the temperature value at each monitoring point at the current time and the initial temperature value, the time interval, and the heat flux coefficient, a material temperature change amplitude value at the future time is obtained, and the formula model of the material temperature change amplitude value includes:

[0028]

[0029] Wherein, ΔWT represents the material temperature change amplitude value; TS represents the time interval; k represents the heat flux coefficient; DT represents the temperature value at each monitoring point at the current time; and ET represents the initial temperature value.

[0030] a sum of the material temperature at the location of each monitoring point at the current time and the material temperature variation amplitude as the material predicted temperature at the location of each monitoring point at the future time;

[0031] based on the material predicted temperature at the location of each monitoring point at the future time, the gas heat exchange rate, the time interval, and the gas temperature value of each monitoring point at the current time, the gas predicted temperature at the location of each monitoring point at the future time is obtained.

[0032] Further, the formula model of the gas predicted temperature comprises:

[0033]

[0034] wherein, QT represents the gas predicted temperature at the location of each monitoring point at the future time; LT represents the material predicted temperature at the location of each monitoring point at the future time; DT represents the gas temperature value of each monitoring point at the current time; L' represents the Euclidean distance between the material and each monitoring point at the current time; TS represents the time interval; ΔT represents the difference between the monitoring point at the location of the material at the current time and each monitoring point in the gas temperature value.

[0035] Further, the gas compensation temperature obtaining method comprises:

[0036] Optionally, one monitoring point is taken as a target point, when the heat compensation power is a certain constant value, the heat conduction coefficient is obtained according to the heat transfer formula, the pipeline temperature at the target point, and the gas temperature value at the target point before and after the opening of the regional heat compensation system, and the heat transfer formula comprises:

[0037] TH = GT + (TQ - GT) × e -αl

[0038] wherein, TH represents the gas compensation temperature at the target point after the opening of the regional heat compensation system; GT represents the pipeline temperature at the target point; TQ represents the gas temperature value at the target point before the opening of the regional heat compensation system; e represents the natural constant; a represents the heat conduction coefficient; and l represents the Euclidean distance between the target point and the regional heat compensation device.

[0039] At each heat compensation power, the gas compensation temperature at each monitoring point after the opening of the heat compensation system is calculated based on the heat transfer formula.

[0040] Further, the heat compensation deviation obtaining method comprises:

[0041] At each heat compensation power, the absolute value of the difference between the average value of the gas predicted temperature at all monitoring points in each region and the average value of the gas compensation temperature is taken as a first temperature deviation factor.

[0042] In each region, differences between the predicted temperature change of the gas and the compensated temperature change of the gas between adjacent monitoring points are analyzed to obtain a second temperature deviation factor;

[0043] The product of the first temperature deviation factor and the second temperature deviation factor of the monitoring points in each region is taken as a temperature deviation coefficient;

[0044] The sum of the temperature deviation coefficients of all regions is normalized to obtain a thermal compensation deviation degree corresponding to each thermal compensation power.

[0045] Further, the method for obtaining the second temperature deviation factor comprises:

[0046] In each region, the monitoring points are arranged in the same order to obtain a sorting sequence;

[0047] In the sorting sequence corresponding to each region, the difference between the predicted temperature of the gas between each two adjacent monitoring points is calculated as a first change factor, and the difference between the compensated temperature of the gas between each two adjacent monitoring points is calculated as a second change factor;

[0048] The absolute value of the difference between the mean value of the first change factor and the mean value of the second change factor corresponding to each region is taken as the second temperature deviation factor.

[0049] Further, the method for obtaining the optimal thermal compensation power comprises:

[0050] Among all the thermal compensation powers, the thermal compensation power with the minimum thermal compensation deviation degree is taken as the optimal thermal compensation power.

[0051] An internal temperature precise regulation device of an energy-saving rotary kiln comprises a processor and a memory, and the memory stores at least one instruction, at least one program, a code set or an instruction set. When the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor, the steps of the internal temperature precise regulation method of the energy-saving rotary kiln are realized.

[0052] The present application has the following beneficial effects:

[0053] The present application mainly aims at the problem that during the operation of the rotary kiln, due to the differences in the state of the material, heat exchange and heat transfer mode in different areas (cooling zone, firing zone, preheating zone) of the kiln body, the temperature distribution is uneven, resulting in fluctuations in the quality of the generated products. First, a regional heat compensation system is constructed, and the heat contained in the exhaust gas generated inside the rotary kiln body is stored and utilized twice, and the heat compensation is realized by controlling the heat flow speed in each area of the rotary kiln to participate in temperature regulation. For the temperature regulation inside the rotary kiln, the gas temperature values are collected at different monitoring points. Since the material temperature inside the rotary kiln cannot be directly measured, because there is a flow of material and a flow of gas inside the rotary kiln, and there is a heat exchange phenomenon between them, the gas flow heat exchange situation between the monitoring points can be analyzed based on the collected gas temperature values, combined with the analysis of the material running phenomenon inside, the material heat exchange situation is analyzed, and then the material temperature at the position of each monitoring point is obtained, and the temperature change of each monitoring point at future time is predicted, and the gas predicted temperature is obtained. Further, under the regional heat compensation system, the gas compensation temperature of each monitoring point under different heat compensation power is obtained according to the heat transfer formula. Then in the adjustment process, the heat compensation deviation degree corresponding to each heat compensation power is determined by the difference between the gas predicted temperature and the gas compensation temperature of the monitoring point at future time, and the heat compensation deviation degree is helpful to select the best heat compensation power, so that under the best heat compensation power, the regional heat compensation system can accurately compensate the gas temperature inside the rotary kiln, so as to realize the accurate control of the temperature inside the rotary kiln, reduce unnecessary heat loss, and effectively improve the energy utilization rate of the rotary kiln. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, and the advantages thereof, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0055] Figure 1 The method flow chart of the internal temperature accurate regulation method of the energy-saving rotary kiln provided by an embodiment of the present application;

[0056] Figure 2 The installation position diagram of the temperature sensor provided by an embodiment of the present application;

[0057] Figure 3 The method flow chart of the heat compensation deviation degree acquisition method provided by an embodiment of the present application;

[0058] Figure 4 A device structure diagram of an internal temperature precise regulation device of an energy-saving rotary kiln provided by an embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined object, the following describes in detail the specific implementation, structure, features and effects of the internal temperature precise regulation method and device of an energy-saving rotary kiln according to the present application in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0061] The following specifically describes the specific scheme of the internal temperature precise regulation method and device of an energy-saving rotary kiln provided by the present application in combination with the accompanying drawings.

[0062] Please refer to Figure 1 which shows a method flowchart of the internal temperature precise regulation method of an energy-saving rotary kiln provided by an embodiment of the present application. The method includes the following steps:

[0063] Step S1: At each monitoring point, the gas temperature value of the rotary kiln at the current time and the pipeline temperature of the outer wall of the rotary kiln body are obtained, and the monitoring points are uniformly distributed in a straight line in each region on the kiln body; the raw material temperature of the inlet is obtained.

[0064] The rotary kiln covers all links from raw material processing to final product formation in the industrial process. Its internal mainly includes a raw material feeding system, a combustion system, a rotary kiln body, a cooling transmission system, a tail gas treatment system and a control system. The material reaction is mainly carried out in the rotary kiln body. The fuel is sprayed into the kiln through the burner to make the material react at high temperature inside, thereby generating the expected product.

[0065] In the embodiment of the present application, the temperature regulation process and method in the rotary kiln are mainly described.

[0066] First, a regional heat compensation system is constructed to collect a large amount of heat energy contained in the exhaust gas to compensate for the heating of the rotary kiln body, so as to realize the secondary utilization of the heat energy in the exhaust gas.

[0067] Specifically, the regional heat compensation system is controlled by a regional heat compensation device, which includes a waste gas collecting device, a filtering device, a heat accumulator, a waste gas return device and a controller, the waste gas collecting device is installed at the tail end of the rotary kiln body, and a large amount of heat energy is contained in the collected waste gas; the collected waste gas is filtered through the filtering device to remove the dust and harmful gas contained therein and improve the heat utilization efficiency; the filtered waste gas is transmitted to the heat accumulator; the tail end of the heat accumulator is connected to the waste gas return device, the waste gas return device is connected to the heating pipe outside the rotary kiln body, and the controller controls the waste gas flow speed in the heating pipe by adjusting the heat compensation power, so that the gas temperature in the rotary kiln is compensated.

[0068] The movement of the material in the rotary kiln is mainly through the height difference formed by the material inlet and outlet of the kiln body and rotation, so that the internal material realizes downward sliding in the process of uniform heating reaction, in the embodiment of the present application, the rotary kiln body is divided into three regions, which are cooling zone, firing zone and preheating zone, then the monitoring points are uniformly arranged in straight lines in each region of the rotary kiln body, and temperature sensors are installed at each monitoring point, please refer to Figure 2 which shows the installation position of the temperature sensor in one embodiment of the present application, the temperature sensor is used for collecting the gas temperature value in the rotary kiln and the pipe temperature outside the rotary kiln body, and a temperature sensor is also installed at the inlet of the rotary kiln for obtaining the raw material temperature.

[0069] Step S2: based on the change of the gas temperature value between the monitoring points and the positional relationship, the gas heat exchange condition is analyzed, and the material temperature at the position of each monitoring point at the current time is calculated in combination with the material heat exchange condition of the material in the rotary kiln and the material flow time; according to the gas temperature value of the monitoring point at the current time and the material temperature at the position of the monitoring point, the predicted gas temperature at the position of the monitoring point at the future time is obtained.

[0070] In the whole temperature flow system of the rotary kiln, the temperature fluctuation in a single region will have different degrees of influence on the surrounding monitoring points, and the influence of the temperature flow is affected by the temperature gradient between the internal monitoring points, the heat conduction of air and the heat radiation in the internal material flow process, for this, the related characteristics of the current kiln monitoring points are analyzed, and then the internal temperature flow model of the rotary kiln is constructed.

[0071] In the cooling zone, the air exchanges heat with the material, causing the temperature to rise. Subsequently, the air enters the firing zone to receive further heating. The high-temperature gas continues to move towards the inlet, in the process of which it continuously exchanges heat with the material, causing the temperature to gradually decrease. In the entire heat exchange process, the temperature sensor at the monitoring point can only monitor the gas temperature value inside the rotary kiln body, and cannot directly collect the temperature of the material flowing inside. However, since the material and the gas coexist, heat exchange occurs. Therefore, by monitoring the change in the gas temperature value between the monitoring points and the positional relationship, the heat exchange of the gas in the rotary kiln can be analyzed. Combined with the heat exchange of the material in the kiln and the flow time of the material, the material temperature at the location of each monitoring point at the current time can be calculated. That is, the heat exchange phenomenon inside the rotary kiln body is analyzed, and the material temperature inside the rotary kiln is inversely deduced.

[0072] Preferably, in one embodiment of the present application, the method for obtaining the material temperature comprises:

[0073] In each region, the gas heat exchange rate per unit time is obtained according to the Euclidean distance between the monitoring points and the gas temperature value. The formula model of the gas heat exchange rate comprises:

[0074]

[0075] wherein RT1 represents the gas heat exchange rate between any two monitoring points; T represents the gas temperature value of the monitoring point farthest from the inlet among the two monitoring points; T1 represents the gas temperature value of the monitoring point closest to the inlet among the two monitoring points; and L represents the Euclidean distance between the two monitoring points.

[0076] In the formula model of the gas heat exchange rate, the temperature difference represented by the numerator is used to reflect the temperature change caused by heat exchange. The greater the difference, the higher the heat exchange rate. Since the overall air flow rate inside the rotary kiln body is considered to be uniform, the heat exchange time experienced by the temperature difference between the two monitoring points can be measured by the Euclidean distance between the corresponding monitoring points. The smaller the Euclidean distance in the denominator, the greater the temperature difference in the numerator, and the greater the gas heat exchange rate.

[0077] At this point, the formula model of the gas heat exchange rate can obtain the gas heat exchange rate per unit time between any two monitoring points, which is used to reflect the heat exchange of the gas.

[0078] In the firing zone of the kiln body, the high-temperature coal gas sprayed makes the gas temperature rise, and at the same time, the material temperature also rises, so in the embodiment of the present application, the temperature difference between the gas temperature and the material temperature at the monitoring point at the center of the firing zone of the kiln body is considered to be 0, and therefore the position of the monitoring point at the center of the firing zone of the kiln body is taken as the comparison position, and it is considered that the gas temperature and the material temperature at the comparison position are the same, so the gas temperature at the comparison position at the current time is taken as the comparison temperature.

[0079] Since the material temperature cannot be directly measured throughout the process, the first material heat exchange rate is calculated based on the temperature change of the raw material at the charging port during the flow process in the kiln body.

[0080] Based on the comparison temperature and the raw material temperature at the charging port, the first material heat exchange rate is obtained, and the formula model of the first material heat exchange rate includes:

[0081] RT' = h x A x (T' - T")

[0082] Wherein, RT' represents the first material heat exchange rate; h represents the convective heat transfer coefficient; A represents the heat transfer area; T' represents the raw material temperature at the charging port; T" represents the comparison temperature; h x A represents the heat flow coefficient, denoted as k.

[0083] In the formula model of the first material heat exchange rate, the heat flow coefficient is an unknown quantity, and the first material heat exchange rate is also an unknown quantity. However, since the material and the gas coexist in the same space and will produce heat exchange phenomenon, the heat flow coefficient is obtained by simultaneously solving the first material heat exchange rate and the gas heat exchange rate.

[0084] Based on the foregoing analysis, it can be known that the formula model of the gas heat exchange rate can obtain the gas heat exchange rate between any two monitoring points per unit time, so the heat flow coefficient is obtained according to the first material heat exchange rate and the gas heat exchange rate between the comparison position and the monitoring point closest to the charging port, and combined with the material flow time between the comparison position and the monitoring point closest to the charging port. The material flow time can be calculated according to the material flow speed and the distance between the positions.

[0085] The formula model of the heat flow coefficient includes:

[0086]

[0087] Wherein, k represents the heat flow coefficient; RT2 represents the gas heat exchange rate per unit time between the comparison position and the monitoring point closest to the charging port; t represents the material flow time between the comparison position and the monitoring point closest to the charging port; T' represents the raw material temperature at the charging port; T" represents the comparison temperature.

[0088] Thus, the unknown heat flow coefficient can be obtained.

[0089] Finally, according to the gas heat exchange rate between the comparison position and any one monitoring point position, the heat flow coefficient and the comparison temperature, the material temperature at the position of the monitoring point at the current time can be calculated, and the formula model of the material temperature includes:

[0090]

[0091] Wherein, WR represents the material temperature at the position of any one monitoring point at the current time; T" represents the comparison temperature; RT3 represents the gas heat exchange rate between the comparison position and any one monitoring point position; k represents the heat flow coefficient; t' represents the material flow time between the comparison position and any one monitoring point position.

[0092] In the formula model of the material temperature, The temperature difference between the comparison position and any one monitoring point position is represented, so the comparison temperature and the temperature difference are added to obtain the material temperature at any one monitoring point position.

[0093] The regional heat compensation system can compensate the heat of the gas in the rotary kiln body, and predicting the temperature change of each monitoring point at the future time can help to find the most suitable heat compensation state to maintain the stability of the temperature in the rotary kiln body. The change of the gas temperature in the rotary kiln body is mainly affected by the heat conduction temperature during the material flow, so for each monitoring point, the predicted gas temperature at the future time can be predicted according to the gas temperature value of the monitoring point at the current time and the material temperature at the position of the monitoring point.

[0094] Preferably, in an embodiment of the present application, the method for obtaining the predicted gas temperature comprises:

[0095] The difference between the future time and the current time is taken as the time interval, and the future time can be set according to the implementation scene, for example, if the current time is 5 and the future time is 8, then the time interval is 3.

[0096] The monitoring point between the monitoring point and the inlet is taken as the monitoring point to be measured, and the purpose of determining the monitoring point to be measured is to select the monitoring point which can flow through the material and may affect the temperature within the time interval; the average value of the material temperature at the position of all monitoring points to be measured at the current time is taken as the initial temperature value of each monitoring point, and the initial temperature value provides a reference value for subsequent calculation and analysis, and the average value can be taken as a relatively reasonable temperature estimate.

[0097] Then, according to the difference between the temperature value at each monitoring point at the current time and the initial temperature value, the time interval and the heat flow coefficient, the material temperature change amplitude value at the future time is obtained, and the formula model of the material temperature change amplitude value includes:

[0098]

[0099] Wherein, ΔWT represents the material temperature change amplitude value; TS represents the time interval; k represents the heat flow coefficient; DT represents the temperature value at each monitoring point at the current time; ET represents the initial temperature value.

[0100] In the formula model of the material temperature change amplitude, (DT-ET) represents the temperature difference, and multiplying the temperature difference by the heat flow coefficient can obtain the material heat exchange rate (refer to the formula model of the first material heat exchange rate), and then integrating the material heat exchange rate in the time interval, the temperature change amplitude value of the material flow in the time interval is obtained.

[0101] The sum of the material temperature at each monitoring point at the current time and the material temperature change amplitude is used as the material predicted temperature at each monitoring point at the future time.

[0102] Finally, based on the material predicted temperature at each monitoring point at the future time, the gas heat exchange rate, the time interval and the gas temperature value at each monitoring point at the current time, the gas predicted temperature at each monitoring point at the future time is obtained, and the formula model of the gas predicted temperature includes:

[0103]

[0104] Wherein, QT represents the gas predicted temperature at each monitoring point at the future time; LT represents the material predicted temperature at each monitoring point at the future time; DT represents the gas temperature value at each monitoring point at the current time; L' represents the Euclidean distance between the material and each monitoring point at the current time; TS represents the time interval; ΔT represents the difference between the gas temperature values between the monitoring point at the material position at the current time and each monitoring point.

[0105] In the formula model of the gas predicted temperature, represents the gas heat exchange rate (refer to the formula model of the gas heat exchange rate), represents the temperature difference when the gas predicted temperature of each monitoring point at the predicted future time, and ΔT represents the temperature difference at the current time, The temperature change range value in the time interval between the current time and the future time is represented, and then the gas temperature value at each monitoring point at the current time is added to the temperature change range value, so that the predicted gas temperature at the location of each monitoring point at the future time is obtained.

[0106] It should be noted that the calculation of the Euclidean distance between the material and the monitoring point can be roughly set as the Euclidean distance between the center position of the material and the monitoring point.

[0107] Step S3: Based on the heat transfer formula, the gas compensation temperature at the location of each monitoring point under each heat compensation power after heat compensation is predicted under different heat compensation powers.

[0108] The regional heat compensation system in the embodiment of the present application can control the gas temperature inside the rotary kiln body by utilizing the temperature contained in the exhaust gas twice, so that the reaction of the material inside the rotary kiln in each region is more sufficient.

[0109] The controller in the regional heat compensation system adjusts the flow speed of the exhaust gas in the heating pipe to compensate for the gas temperature inside the rotary kiln, so the gas compensation temperature at the location of each monitoring point under different heat compensation powers can be analyzed, which helps to analyze the pros and cons of the heat compensation provided by different heat compensation powers in the subsequent process.

[0110] In the regional heat compensation process, heat exchange usually occurs between the pipe temperature of the outer wall of the rotary kiln and the gas temperature after the regional heat compensation system is started, and therefore, preferably, the method for obtaining the gas compensation temperature in one embodiment of the present application comprises:

[0111] Optionally, one monitoring point is selected as a target point, and when the heat compensation power is a certain constant value, the heat conduction coefficient is obtained according to the heat transfer formula, the pipe temperature at the target point and the gas temperature value at the target point before and after the regional heat compensation system is started, and the heat transfer formula comprises:

[0112] TH=GT+(TQ-GT)×e -αl

[0113] Wherein, TH represents the gas compensation temperature at the target point after the regional heat compensation system is started; GT represents the pipe temperature at the target point; TQ represents the gas temperature value at the target point before the regional heat compensation system is started; e represents a natural constant; a represents the heat conduction coefficient; and l represents the Euclidean distance between the target point and the regional heat compensation device.

[0114] In the heat transfer formula, since there is an unknown number a, a specific heat compensation power, for example, P, can be set, and then the unknown number a can be obtained by substituting the above formula.

[0115] Then different heat compensation powers are preset, and under each heat compensation power, the gas compensation temperatures at each monitoring point after starting the heat compensation system are calculated based on a heat transfer formula.

[0116] It should be noted that the heat transfer formula in this embodiment of the present application is a known model, and the specific construction principle is not described here; different heat compensation powers are preset, which can be specifically set to 400 watts, 600 watts, and 800 watts, and the specific setting can be adjusted according to the implementation scene, which is not limited here.

[0117] Step S4: Under each heat compensation power, the difference between the gas compensation temperature at the position of each monitoring point and the gas predicted temperature at the future time is analyzed to obtain the heat compensation deviation corresponding to each heat compensation power; the best heat compensation power is determined based on the heat compensation deviation to perform heat compensation on the gas temperature inside the rotary kiln.

[0118] The gas temperature control in the rotary kiln is crucial to the stability and safety of the production process, and through accurate heat compensation, the temperature stability in the production process can be ensured. Based on the foregoing steps, the gas compensation temperature under each heat compensation power after starting the regional heat compensation and the gas predicted temperature at the future time can be obtained, and then the deviation between the two can be analyzed to quantify the heat compensation deviation for screening the best heat compensation power, which not only helps to achieve more accurate temperature control, but also can avoid unnecessary energy waste.

[0119] Preferably, the method for obtaining the heat compensation deviation in one embodiment of the present application comprises:

[0120] Please refer to Figure 3 which shows the method flowchart of the method for obtaining the heat compensation deviation in one embodiment of the present application, which comprises the following steps:

[0121] Step S401: Under each heat compensation power, the difference between the gas predicted temperature and the gas compensation temperature at all monitoring points in each region is analyzed to obtain a first temperature deviation factor.

[0122] The average value of the gas predicted temperature at the positions of all monitoring points in each region is calculated as the average value of the gas predicted temperature, which is used to reflect the overall average level of the gas predicted temperature of all monitoring points in each region; similarly, the average value of the gas compensation temperature at the positions of all monitoring points in each region is calculated as the average value of the gas compensation temperature, which is used to reflect the overall average level of the gas compensation temperature of all monitoring points in each region.

[0123] The absolute value of the difference between the average of the corresponding gas predicted temperature and the average of the gas compensation temperature in each region is taken as a first temperature deviation factor, and the greater the first temperature deviation factor, the less ideal the temperature adjustment effect of the current compensation heat power; on the contrary, the smaller the first temperature deviation factor, the better the temperature adjustment effect of the current heat compensation power, which can provide more appropriate heat compensation.

[0124] Step S402: Under each heat compensation power, in each region, the difference between the gas predicted temperature change and the gas compensation temperature change between adjacent monitoring points is analyzed to obtain a second temperature deviation factor.

[0125] In this step, the embodiment of the present application further analyzes the local performance of the heat compensation provided by each heat compensation power in each region.

[0126] First, in each region, the monitoring points are arranged in the same order to obtain an ordered sequence (which can be arranged in the order of moving away from the inlet to the inlet on the rotary kiln body, and the specific arrangement method is not limited).

[0127] The temperature change difference between adjacent monitoring points is an important indicator for evaluating the local performance of the regional heat compensation system. Therefore, in the corresponding ordered sequence of each region, the difference between the gas predicted temperature of each adjacent two monitoring points is calculated as a first change factor, and similarly, the difference between the gas compensation temperature of each adjacent two monitoring points is calculated as a second change factor.

[0128] The absolute value of the difference between the average of the corresponding first change factor and the average of the second change factor in each region is taken as a second temperature deviation factor, and the greater the second temperature deviation factor, the worse the heat compensation effect of the current heat compensation power in the local range; on the contrary, the smaller the second temperature deviation factor, the closer the heat compensation effect of the current heat compensation power in the local range to the gas temperature at the future moment, that is, the better the heat compensation effect.

[0129] Step S403: Under each heat compensation power, the first temperature deviation factor and the second temperature deviation factor of all regions are fused to obtain a heat compensation deviation degree corresponding to each heat compensation power.

[0130] Based on the foregoing analysis, at each thermal compensation power, if the first temperature deviation factor corresponding to a certain region is larger, it indicates that the temperature regulation effect of the current compensation thermal power is not ideal as a whole; and if the second temperature deviation factor is larger, it indicates that the heat compensation effect of the current thermal compensation power is poor in a local range. Therefore, the product of the first temperature deviation factor and the second temperature deviation factor corresponding to the monitoring point in each region is taken as the temperature deviation coefficient. The larger the temperature deviation coefficient is, the less ideal the heat compensation effect of the current thermal compensation power on the gas temperature in the region is.

[0131] Finally, the sum of the normalized values of the temperature deviation coefficients corresponding to all regions is taken as the thermal compensation deviation degree corresponding to each thermal compensation power. At this time, the smaller the thermal compensation deviation degree is, the more close the heat compensation effect of the current thermal compensation power to the predicted gas temperature at the future moment, and the better the temperature regulation effect is. The normalization is a technology known to those skilled in the art, and the selection of the normalization function can be linear normalization or standard normalization, and the specific normalization method is not limited herein.

[0132] At this point, the thermal compensation deviation degree of each thermal compensation power can be obtained based on the deviation between the predicted gas temperature at the future moment of each monitoring point in the rotary kiln body and the gas compensation temperature of the monitoring point at each thermal compensation power, and then the best thermal compensation power can be selected based on this index to compensate for the gas temperature inside the rotary kiln in the time interval from the current moment to the future moment.

[0133] Preferably, in an embodiment of the present application, the method for obtaining the best thermal compensation power comprises:

[0134] Based on the foregoing analysis, the smaller the thermal compensation deviation degree is, the more close the heat compensation effect of the current thermal compensation power to the predicted gas temperature at the future moment, and the better the temperature regulation effect is. Therefore, the thermal compensation power with the smallest thermal compensation deviation degree is taken as the best thermal compensation power among all thermal compensation powers.

[0135] After obtaining the best thermal compensation power in the time interval from the current moment to the future moment, the controller in the regional thermal compensation system is used to control the temperature of the exhaust gas according to the best thermal compensation power, thereby realizing accurate regulation and control of the temperature inside the rotary kiln.

[0136] In summary, the embodiment of the present application is mainly aimed at the problem that the temperature distribution is uneven and the quality of the generated product fluctuates due to the differences in the state of the material, heat exchange and heat transfer mode in different regions (cooling zone, firing zone, preheating zone) of the kiln body during the operation of the rotary kiln. First, a regional heat compensation system is constructed, and the heat contained in the exhaust gas generated inside the rotary kiln is stored and utilized again, and the heat compensation is realized by controlling the heat flow speed in each region of the rotary kiln to participate in temperature regulation. For the temperature regulation inside the rotary kiln, the gas temperature values are collected at different monitoring points. Since the material temperature inside the rotary kiln cannot be directly measured, but because there is a flow of material and a flow of gas inside the rotary kiln, and there is heat exchange between them, the gas heat exchange between the monitoring points can be analyzed based on the collected gas temperature values, and the material heat exchange can be analyzed in combination with the phenomenon of the material operation inside the rotary kiln, so as to obtain the material temperature at the position of each monitoring point, and then predict the temperature change of each monitoring point at a future time to obtain the predicted gas temperature. Further, under the regional heat compensation system, the gas compensation temperature of each monitoring point under different heat compensation powers is obtained according to the heat transfer formula. Then, in the adjustment process, the heat compensation deviation corresponding to each heat compensation power is determined by the difference between the predicted gas temperature of the monitoring point at the future time and the gas compensation temperature, and the heat compensation deviation is helpful to select the best heat compensation power, so that under the best heat compensation power, the regional heat compensation system can accurately compensate the gas temperature inside the rotary kiln, so as to realize accurate temperature control inside the rotary kiln, reduce unnecessary heat loss, and effectively improve the energy utilization rate of the rotary kiln.

[0137] The embodiment of the present application also provides an internal temperature accurate regulation device of an energy-saving rotary kiln, which comprises a processor and a memory, and the memory stores at least one instruction, at least one program, a code set or an instruction set. When the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor, the steps of an internal temperature accurate regulation method of an energy-saving rotary kiln are realized.

[0138] Please refer to Figure 4The device structure schematic diagram of the internal temperature accurate regulation device of the energy-saving rotary kiln is shown, and the device structure schematic diagram comprises a processor 500, a memory 501, a bus 502 and a communication interface 503, the processor 500, the communication interface 503 and the memory 501 are connected through the bus 502, wherein the memory 501 can contain a high-speed random access memory, the bus 502 can be an ISA bus, a PCI bus or an EISA bus, etc., the processor 500 can be an integrated circuit chip, and has a signal processing capability; the memory 501 stores at least one instruction, at least one program, a code set or an instruction set, and the at least one instruction, the at least one program, the code set or the instruction set are loaded and executed by the processor to realize the steps in the internal temperature accurate regulation method of the energy-saving rotary kiln.

[0139] It should be noted that the above-mentioned embodiment sequence of the application is only for description, and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are also possible or can be advantageous.

[0140] Each embodiment in the specification is described in a progressive manner, and the same and similar parts between each embodiment can be referred to each other, and each embodiment mainly describes the difference from other embodiments.

Claims

1. A method for precisely controlling the temperature inside an energy-saving rotary kiln, characterized by, The method comprises a regional heat compensation system, a kiln body is divided into three regions, which are cooling zone, firing zone and preheating zone, and the method comprises: At each monitoring point, the gas temperature value of the rotary kiln interior at the current time and the pipeline temperature of the rotary kiln body outer wall are acquired, the monitoring points are uniformly distributed in a straight line in each region on the kiln body; the raw material temperature of the feeding port is acquired; Based on the change of the gas temperature value between the monitoring points and the positional relationship, the gas heat exchange condition is analyzed, and combined with the material heat exchange condition of the material in the rotary kiln interior and the material flow time, the material temperature at the position of each monitoring point at the current time is calculated; according to the gas temperature value of the monitoring point at the current time and the material temperature at the position of the monitoring point, the predicted gas temperature at the position of the monitoring point at the future time is obtained; Under different heat compensation powers, based on the heat transfer formula, the gas compensation temperature at the position of each monitoring point under each heat compensation power after heat compensation is predicted; Under each heat compensation power, the difference between the gas compensation temperature at the position of each monitoring point and the predicted gas temperature at the future time is analyzed, and the heat compensation deviation degree corresponding to each heat compensation power is obtained; the best heat compensation power is determined based on the heat compensation deviation degree, so as to perform heat compensation on the gas temperature in the rotary kiln.

2. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 1, characterized in that, The method for acquiring the material temperature comprises: In each region, the gas heat exchange rate per unit time is acquired according to the Euclidean distance between the monitoring points and the gas temperature value, and the formula model of the gas heat exchange rate comprises: Wherein, RT1 represents the gas heat exchange rate between any two monitoring points; T represents the gas temperature value of the monitoring point farthest from the feeding port among any two monitoring points; T1 represents the gas temperature value of the monitoring point closest to the feeding port among any two monitoring points; L represents the Euclidean distance between any two monitoring points; The position of the monitoring point at the center of the firing zone of the kiln body is taken as a comparison position, it is considered that the gas temperature value at the comparison position is the same as the material temperature, and the gas temperature value at the comparison position at the current time is taken as a comparison temperature; Based on the comparison temperature and the raw material temperature of the feeding port, a first material heat exchange rate is acquired, and the formula model of the first material heat exchange rate comprises: RT' = h x A x (T' - T'') Wherein, RT' represents the first material heat exchange rate; h represents the convective heat transfer coefficient; A represents the heat transfer area; T' represents the raw material temperature of the feeding port; T'' represents the comparison temperature; h x A represents the heat flow flux coefficient, denoted as k; According to the gas heat exchange rate between the comparison position and the position of the monitoring point closest to the feeding port, the first material heat exchange rate and the material flow time between the comparison position and the position of the monitoring point closest to the feeding port, the heat flow flux coefficient is obtained; According to the gas heat exchange rate between the comparison position and the position of any one monitoring point, the heat flow flux coefficient and the comparison temperature, the material temperature at the position of the monitoring point at the current time is calculated, and the formula model of the material temperature comprises: Wherein, WR represents the material temperature at the position of any one monitoring point at the current time; T" represents the contrast temperature; RT3 represents the gas heat exchange rate between the contrast position and the position of any one monitoring point; k represents the heat flow coefficient.

3. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 2, characterized in that, The formula model of the heat flow coefficient comprises: Wherein, k represents the heat flow coefficient; RT2 represents the gas heat exchange rate between the contrast position and the position of the monitoring point closest to the material inlet per unit time; t represents the material flow time between the contrast position and the position of the monitoring point closest to the material inlet; T' represents the raw material temperature at the material inlet; T" represents the contrast temperature.

4. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 3, characterized in that, The method for obtaining the gas predicted temperature comprises: Taking the difference between the future time and the current time as a time interval, taking the monitoring point whose material flow time between the monitoring point and the material inlet is less than the time interval as a monitoring point to be measured, and taking the average of the material temperatures at the positions of all the monitoring points to be measured at the current time as the initial temperature value at each monitoring point; According to the difference between the temperature value at each monitoring point at the current time and the initial temperature value, the time interval and the heat flow coefficient, a material temperature change amplitude value at the future time is obtained, and the formula model of the material temperature change amplitude value comprises: Wherein, ΔWT represents the material temperature change amplitude value; TS represents the time interval; k represents the heat flow coefficient; DT represents the temperature value at each monitoring point at the current time; ET represents the initial temperature value; The sum of the material temperature at the position of each monitoring point at the current time and the material temperature change amplitude value is taken as the material predicted temperature at the position of each monitoring point at the future time. Based on the material predicted temperature at the position of each monitoring point at the future time, the gas heat exchange rate, the time interval and the gas temperature value of each monitoring point at the current time, the gas predicted temperature at the position of each monitoring point at the future time is obtained.

5. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 4, characterized in that, The formula model of the gas predicted temperature comprises: Wherein, QT represents the gas predicted temperature at the position of each monitoring point at the future time; LT represents the material predicted temperature at the position of each monitoring point at the future time; DT represents the gas temperature value at each monitoring point at the current time; L' represents the Euclidean distance between the material at the current time and each monitoring point; TS represents the time interval; ΔT represents the difference between the gas temperature values between the monitoring point at the position of the material at the current time and each monitoring point.

6. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 1, characterized in that, The method for obtaining the gas compensation temperature comprises: Optionally, one monitoring point is taken as a target point, when the heat compensation power is a certain constant value, the heat transfer coefficient is obtained according to the heat transfer formula, the pipe temperature at the target point and the gas temperature value at the target point before and after the opening of the regional heat compensation system, and the heat transfer formula comprises: TH = GT + (TQ - GT) x e -αl Wherein, TH represents the gas compensation temperature at the target point after the opening of the regional heat compensation system; GT represents the pipe temperature at the target point; TQ represents the gas temperature value at the target point before the opening of the regional heat compensation system; e represents the natural constant; a represents the heat transfer coefficient; l represents the Euclidean distance between the target point and the regional heat compensation device; At each heat compensation power, the gas compensation temperature at each monitoring point after starting the heat compensation system is calculated based on a heat transfer formula.

7. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 1, characterized in that, The method for obtaining the heat compensation deviation degree comprises: At each heat compensation power, the absolute value of the difference between the average of the gas predicted temperature at all monitoring points in each region and the average of the gas compensation temperature is taken as a first temperature deviation factor; In each region, the difference between the change of the gas predicted temperature and the change of the gas compensation temperature between adjacent monitoring points is analyzed, thereby obtaining a second temperature deviation factor; The product of the first temperature deviation factor and the second temperature deviation factor of each monitoring point in each region is taken as a temperature deviation coefficient; The sum of the temperature deviation coefficients of all regions is normalized, and the normalized value is taken as the heat compensation deviation degree corresponding to each heat compensation power.

8. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 7, characterized in that, The method for obtaining the second temperature deviation factor comprises: In each region, the monitoring points are arranged in the same order to obtain an ordered sequence; In the ordered sequence of each region, the difference between the gas predicted temperature of each adjacent two monitoring points is taken as a first change factor, and the difference between the gas compensation temperature of each adjacent two monitoring points is taken as a second change factor; The absolute value of the difference between the average of the first change factor and the average of the second change factor of each region is taken as the second temperature deviation factor.

9. The method for precisely controlling the internal temperature of an energy-saving rotary kiln according to claim 1, characterized in that, The method for obtaining the optimal heat compensation power comprises: Among all the heat compensation powers, the heat compensation power with the minimum heat compensation deviation degree is taken as the optimal heat compensation power.

10. An internal temperature accurate control device of an energy-saving rotary kiln, characterized in that, The device comprises a processor and a memory, and the memory stores at least one instruction, at least one program, a code set or an instruction set. When the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor, the steps of the method for accurately controlling the internal temperature of the energy-saving rotary kiln according to any one of claims 1-9 are implemented.

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