A system and method for determining the stability of materials in a continuous graphitization and purification furnace

Abstract

A system and method for determining the stability of materials in a continuous graphitization and purification furnace, comprising an infrared temperature measuring device, a weighing device, a pressure sensor, and a PLC electrically connected to the infrared temperature measuring device, the weighing device and the pressure sensor; characterized in that the infrared temperature measuring device is used to collect the temperatures of multiple measuring points in the continuous graphitization and purification furnace in real time, and transmit them to the PLC in real time; the weighing device is used to measure the weight of materials entering the continuous graphitization and purification furnace in real time, and the weight of materials discharged from the continuous graphitization and purification furnace in real time, and transmit them to the PLC in real time; the pressure sensor is used to measure the air pressure in the continuous graphitization and purification furnace in real time, and transmit it to the PLC in real time; the PLC comprehensively determines the stability of materials in the continuous graphitization and purification furnace based on three evaluation factors: temperature change rate, weight deviation rate, and pressure change rate in the continuous graphitization and purification furnace.

Description

Technical Field

[0001] The present invention relates to the technical field of graphitization production furnaces, and in particular to a system for determining the stability of materials in a continuous graphitization and purification furnace; the present invention also relates to a method for determining the stability of materials in a continuous graphitization and purification furnace. Background Art

[0002] In the field of graphitization production furnace technology, although the Acheson furnace is widely used, it is an intermittent furnace for periodic production. Due to the discontinuous production, it brings disadvantages such as low production capacity, quality fluctuations, high power consumption, and poor operating environment. Therefore, the continuous furnace has become an important topic and goal of world attention and research and development. There are two types of continuous furnaces currently being tested. One is a single-function graphitization furnace, that is, after the carbon products are roasted, they can be continuously produced into graphitized products through the continuous furnace, which is called a single furnace. The other is a multifunctional combined type, that is, a double-type furnace that integrates the two processes of roasting and graphitization, and a triple-type furnace that integrates the three processes of pressing, roasting, and graphitization.

[0003] The continuous graphitization and purification furnace is a continuous graphite purification thermal equipment. The material to be treated enters the furnace through the feeder and gradually moves to the heating zone, where it is graphitized at high temperature, then gradually passes through the cooling zone, and finally the product is obtained through the discharger.

[0004] Continuous graphitization and purification furnaces usually add a constant pressure device to ensure the stability of the raw material processing process. However, since the amount of raw materials passing through the electric field is difficult to control, and the graphite column of the positive electrode will gradually shorten during use, the actual power will fluctuate, making it difficult to ensure the stability of production. During the operation of the continuous high-temperature graphitization furnace, the materials in the furnace are in a state that cannot be directly observed. There is currently no effective solution to the problem of determining the stability of the materials. However, in the graphitization production process, the stable and continuous flow of materials is crucial and is a prerequisite for the mass production of high-purity graphite. Once the furnace is blocked, it will affect the quality and output of the finished product, and in severe cases may even cause production accidents.

[0005] Therefore, it is of great significance to study the determination of the stability of continuous graphitization and purification furnaces to avoid quality fluctuations and production accidents during the production process. Summary of the invention

[0006] The present invention aims to solve at least one defect in the prior art. To this end, the technical problem solved by the present invention is to propose a system for determining the stability of materials in a continuous graphitization and purification furnace, and to provide a method for determining the stability of materials in a continuous graphitization and purification furnace, which can timely determine the stability of materials in a continuous graphitization and purification furnace, and provide early warning information to avoid quality fluctuations and production accidents in the production process.

[0007] In order to solve the above technical problems, on the one hand, the present invention provides a method for determining the stability of materials in a continuous graphitization and purification furnace, comprising the following steps:

[0008] The infrared temperature measuring device detects the temperature of multiple measuring points in the continuous graphitization and purification furnace in real time and transmits it to the PLC in real time;

[0009] The weighing device measures the weight of the material entering the continuous graphitization and purification furnace in real time, and measures the weight of the material discharged from the continuous graphitization and purification furnace in real time, and transmits it to the PLC in real time;

[0010] The pressure sensor detects the gas pressure in the continuous graphitization and purification furnace in real time and transmits it to the PLC in real time;

[0011] PLC comprehensively determines the stability of materials in the continuous graphitization and purification furnace based on three evaluation factors: temperature change rate, weight deviation rate, and pressure change rate in the continuous graphitization and purification furnace. The determination process is as follows:

[0012] (I) Establish a set of evaluation factors U for comprehensive evaluation of material stability, including:

[0013] 1) Temperature change rate u1: When the continuous graphitization and purification furnace is heated to the target temperature required by the process, the smaller the temperature change rate, the better the stability of the material in the furnace.

[0014] PLC calculates the temperature change rate u1 according to the following formula

[0015]

[0016] Where t1 is the average temperature value detected at each measuring point at the beginning of the time period, in °C

[0017] t2 is the average temperature value detected at each measuring point at the end of the time period, in °C

[0018] T is the time period, in min;

[0019] 2) Weight deviation rate u2, the weight deviation rate is maintained at a small value, indicating that the material stability in the continuous graphitization and purification furnace is good,

[0020] PLC calculates the weight deviation rate u2 according to the following formula

[0021]

[0022] Where w1 is the cumulative weight of materials input into the continuous graphitization and purification furnace during the time period, unit Kg

[0023] w2 is the cumulative weight of the material output from the continuous graphitization and purification furnace during the time period, in kg;

[0024] 3) Pressure change rate u3. The smaller the pressure change rate, the more the gas pressure in the furnace is in a dynamic equilibrium state and the better the material stability.

[0025] PLC calculates the pressure change rate u3 according to the following formula

[0026]

[0027] Where p1 is the gas pressure detection value in the continuous graphitization and purification furnace at the beginning of the time period, in Pa

[0028] p2 is the gas pressure detection value in the continuous graphitization and purification furnace at the end of the time period, in Pa

[0029] T is the time period, in min;

[0030] Thus, we obtain the evaluation factor set U = {u1, u2, u3}, i.e., the numerical combination of u1, u2, u3, corresponding to a specific working condition;

[0031] (ii) Set the evaluation set V = {v1, v2, v3} = {good, qualified, poor} for each factor, and set the membership function of each evaluation factor to the evaluation set V. The membership is used to indicate the degree of conformity of a single factor to the evaluation, with a maximum value of 1 and a minimum value of 0;

[0032] (III) Calculation of fuzzy comprehensive evaluation matrix R

[0033] The membership function of evaluation factor u1 to comment v1 is as follows:

[0034]

[0035] The membership function of evaluation factor u1 to comment v2 is as follows:

[0036]

[0037] The membership function of evaluation factor u1 to comment v3 is as follows:

[0038]

[0039] Substituting the value of u1 into the x in the membership functions A1, A2, and A3, we can obtain the membership vector R1={r 11 ,r 12 ,r 13};

[0040] The membership function of evaluation factor u2 to comment v1 is as follows:

[0041]

[0042] The membership function of evaluation factor u2 to comment v2 is as follows:

[0043] The membership function of evaluation factor u2 to comment v3 is as follows:

[0044]

[0045] Substituting the value of u2 into the x in the membership functions B1, B2, and B3, we can obtain the membership vector R2 = {r 21 ,r 22 ,r 23};

[0046] The membership function of evaluation factor u3 to comment v1 is as follows:

[0047]

[0048] The membership function of evaluation factor u3 to comment v2 is as follows:

[0049]

[0050] The membership function of evaluation factor u3 to comment v3 is as follows:

[0051]

[0052] Substituting the value of u3 into the x in the membership functions C1, C2, and C3, we can obtain the membership vector R3 = {r 31 ,r 32 ,r 33};

[0053] The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3 ;

[0054]

[0055] (iv) Determine the evaluation factor weight vector Q = {q1, q2, q3}, where q1, q2, q3 represent the importance of the three evaluation factors u1, u2, u3, and q1+q2+q3=1;

[0056] (V) Calculate the comprehensive evaluation result S, and use matrix multiplication to calculate S=QR={s1,s2,s3}, where s1,s2,s3 represent the current evaluation factor set U={u1,u2,u3}. For the membership degree of each element v1,v2,v3 of the comment set V, take the maximum value among s1,s2,s3 to get the comprehensive comment of the current working condition; if s1 is the maximum value, give the comment v1: "good"; if s2 is the maximum value, give the comment v2: "qualified"; if s3 is the maximum value, give the comment v3: "poor" and issue an alarm.

[0057] In order to solve the above technical problems, on the other hand, the present invention provides a system for determining the stability of materials in a continuous graphitization and purification furnace, comprising an infrared temperature measuring device, a weighing device, a pressure sensor, and a PLC electrically connected to the infrared temperature measuring device, the weighing device and the pressure sensor; characterized in that the infrared temperature measuring device is used to collect the temperatures of multiple measuring points in the continuous graphitization and purification furnace in real time, and transmit them to the PLC in real time;

[0058] The weighing device is used to measure the weight of the material entering the continuous graphitization and purification furnace in real time, and the weight of the material discharged from the continuous graphitization and purification furnace in real time, and transmit it to the PLC in real time;

[0059] The pressure sensor is used to measure the gas pressure in the continuous graphitization and purification furnace in real time and transmit it to the PLC in real time;

[0060] The PLC comprehensively determines the stability of the materials in the continuous graphitization and purification furnace based on the three evaluation factors of the temperature change rate, weight deviation rate, and pressure change rate in the continuous graphitization and purification furnace. The determination process is as follows:

[0061] (I) Establish a set of evaluation factors U for comprehensive evaluation of material stability, including:

[0062] 1) Temperature change rate u1: When the continuous graphitization and purification furnace is heated to the target temperature required by the process, the smaller the temperature change rate, the better the stability of the material in the furnace.

[0063] PLC calculates the temperature change rate u1 according to the following formula

[0064]

[0065] Where t1 is the average temperature value detected at each measuring point at the beginning of the time period, in °C

[0066] t2 is the average temperature value detected at each measuring point at the end of the time period, in °C

[0067] T is the time period, in min;

[0068] 2) Weight deviation rate u2, the weight deviation rate is maintained at a small value, indicating that the material stability in the continuous graphitization and purification furnace is good,

[0069] PLC calculates the weight deviation rate u2 according to the following formula

[0070]

[0071] Where w1 is the cumulative weight of materials input into the continuous graphitization and purification furnace during the time period, unit Kg

[0072] w2 is the cumulative weight of the material output from the continuous graphitization and purification furnace during the time period, in kg;

[0073] 3) Pressure change rate u3. The smaller the pressure change rate, the more the gas pressure in the furnace is in a dynamic equilibrium state and the better the material stability.

[0074] PLC calculates the pressure change rate u3 according to the following formula

[0075]

[0076] Where p1 is the gas pressure detection value in the continuous graphitization and purification furnace at the beginning of the time period, in Pa

[0077] p2 is the gas pressure detection value in the continuous graphitization and purification furnace at the end of the time period, in Pa

[0078] T is the time period, in min;

[0079] Thus, we obtain the evaluation factor set U = {u1, u2, u3}, i.e., the numerical combination of u1, u2, u3, corresponding to a specific working condition;

[0080] (ii) Set the evaluation set V = {v1, v2, v3} = {good, qualified, poor} for each factor, and set the membership function of each evaluation factor to the evaluation set V. The membership is used to indicate the degree of conformity of a single factor to the evaluation, with a maximum value of 1 and a minimum value of 0;

[0081] (III) Calculation of fuzzy comprehensive evaluation matrix R

[0082] The membership function of evaluation factor u1 to comment v1 is as follows:

[0083]

[0084] The membership function of evaluation factor u1 to comment v2 is as follows:

[0085]

[0086] The membership function of evaluation factor u1 to comment v3 is as follows:

[0087]

[0088] Substituting the value of u1 into the x in the membership functions A1, A2, and A3, we can obtain the membership vector R1={r 11 ,r 12 ,r 13};

[0089] The membership function of evaluation factor u2 to comment v1 is as follows:

[0090]

[0091] The membership function of evaluation factor u2 to comment v2 is as follows:

[0092]

[0093] The membership function of evaluation factor u2 to comment v3 is as follows:

[0094]

[0095] Substituting the value of u2 into the x in the membership functions B1, B2, and B3, we can obtain the membership vector R2 = {r 21 ,r 22 ,r 23};

[0096] The membership function of evaluation factor u3 to comment v1 is as follows:

[0097]

[0098] The membership function of evaluation factor u3 to comment v2 is as follows:

[0099]

[0100] The membership function of evaluation factor u3 to comment v3 is as follows:

[0101]

[0102] Substituting the value of u3 into the x in the membership functions C1, C2, and C3, we can obtain the membership vector R3 = {r 31 ,r 32 ,r 33};

[0103] The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3 ;

[0104]

[0105] (iv) Determine the evaluation factor weight vector Q = {q1, q2, q3}, where q1, q2, q3 represent the importance of the three evaluation factors u1, u2, u3, and q1+q2+q3=1;

[0106] (V) Calculate the comprehensive evaluation result S, and use matrix multiplication to calculate S=QR={s1,s2,s3}, where s1,s2,s3 represent the current evaluation factor set U={u1,u2,u3}. For the membership degree of each element v1,v2,v3 of the comment set V, take the maximum value among s1,s2,s3 to get the comprehensive comment of the current working condition; if s1 is the maximum value, give the comment v1: "good"; if s2 is the maximum value, give the comment v2: "qualified"; if s3 is the maximum value, give the comment v3: "poor" and issue an alarm.

[0107] The technical solution provided by the present invention realizes the judgment of the operating condition of the material in the furnace based on the target temperature and pressure of the continuous graphitization and purification furnace cavity, the weight of the material entering the continuous graphitization and purification furnace, and the weight of the material discharged from the continuous graphitization and purification furnace, and then issues an alarm prompt for the operating condition of the continuous graphitization and purification furnace where the material flow is not smooth, which can prevent and reduce production risks and improve product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0108] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the present application, but do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0109] Figure 1 It is a schematic diagram of the system structure for determining the stability of materials in a continuous graphitization and purification furnace in an embodiment. DETAILED DESCRIPTION

[0110] The present invention will be further described below in conjunction with the embodiments.

[0111] like Figure 1As shown, the system for determining the stability of materials in a continuous graphitization and purification furnace comprises an infrared temperature measuring device 2, a feed weighing device 4, a discharge weighing device 5, a pressure sensor 3, and a PLC 6 electrically connected to the infrared temperature measuring device 2, the feed weighing device 4, the discharge weighing device 5 and the pressure sensor 3; wherein the infrared temperature measuring device is used to collect the temperatures of multiple measuring points in the continuous graphitization and purification furnace 1 in real time, and transmit them to the PLC in real time; the weighing device is used to measure the weight of materials entering the continuous graphitization and purification furnace in real time, and the weight of materials discharged from the continuous graphitization and purification furnace in real time, and transmit them to the PLC in real time; the pressure sensor is used to measure the air pressure in the continuous graphitization and purification furnace in real time, and transmit it to the PLC in real time; the PLC comprehensively determines the stability of materials in the continuous graphitization and purification furnace according to three evaluation factors: temperature change rate, weight deviation rate and pressure change rate in the continuous graphitization and purification furnace.

[0112] The method for determining the stability of materials in a continuous graphitization and purification furnace comprises the following steps:

[0113] The infrared temperature measuring device detects the temperature of multiple measuring points in the continuous graphitization and purification furnace in real time and transmits it to the PLC in real time;

[0114] The weighing device measures the weight of the material entering the continuous graphitization and purification furnace in real time, and measures the weight of the material discharged from the continuous graphitization and purification furnace in real time, and transmits it to the PLC in real time;

[0115] The pressure sensor detects the gas pressure in the continuous graphitization and purification furnace in real time and transmits it to the PLC in real time.

[0116] PLC comprehensively determines the stability of materials in the continuous graphitization and purification furnace based on three evaluation factors: temperature change rate, weight deviation rate, and pressure change rate in the continuous graphitization and purification furnace. The determination process is as follows:

[0117] (I) Establish a set of evaluation factors U for comprehensive evaluation of material stability, including:

[0118] 1) Temperature change rate u1: When the continuous graphitization and purification furnace is heated to the target temperature required by the process, the smaller the temperature change rate, the better the stability of the material in the furnace.

[0119] PLC calculates the temperature change rate u1 according to the following formula

[0120]

[0121] Where t1 is the average temperature value detected at each measuring point at the beginning of the time period, in °C

[0122] t2 is the average temperature value detected at each measuring point at the end of the time period, in °C

[0123] T is the time period, in min;

[0124] 2) Weight deviation rate u2, the weight deviation rate is maintained at a small value, indicating that the material stability in the continuous graphitization and purification furnace is good,

[0125] PLC calculates the weight deviation rate u2 according to the following formula

[0126]

[0127] Where w1 is the cumulative weight of materials input into the continuous graphitization and purification furnace during the time period, unit Kg

[0128] w2 is the cumulative weight of the material output from the continuous graphitization and purification furnace during the time period, in kg;

[0129] 3) Pressure change rate u3. The smaller the pressure change rate, the more the gas pressure in the furnace is in a dynamic equilibrium state and the better the material stability.

[0130] PLC calculates the pressure change rate u3 according to the following formula

[0131]

[0132] Where p1 is the gas pressure detection value in the continuous graphitization and purification furnace at the beginning of the time period, in Pa

[0133] p2 is the gas pressure detection value in the continuous graphitization and purification furnace at the end of the time period, in Pa

[0134] T is the time period, in min;

[0135] Thus, we obtain the evaluation factor set U = {u1, u2, u3}, i.e., the numerical combination of u1, u2, u3, corresponding to a specific working condition;

[0136] (ii) Set the evaluation set V = {v1, v2, v3} = {good, qualified, poor} for each factor, and set the membership function of each evaluation factor to the evaluation set V. The membership is used to indicate the degree of conformity of a single factor to the evaluation, with a maximum value of 1 and a minimum value of 0;

[0137] (III) Calculation of fuzzy comprehensive evaluation matrix R

[0138] The membership function of evaluation factor u1 to comment v1 is as follows:

[0139]

[0140] The membership function of evaluation factor u1 to comment v2 is as follows:

[0141]

[0142] The membership function of evaluation factor u1 to comment v3 is as follows:

[0143]

[0144] Substituting the value of u1 into the x in the membership functions A1, A2, and A3, we can obtain the membership vector R1={r 11 ,r 12 ,r 13};

[0145] The membership function of evaluation factor u2 to comment v1 is as follows:

[0146]

[0147] The membership function of evaluation factor u2 to comment v2 is as follows:

[0148]

[0149] The membership function of evaluation factor u2 to comment v3 is as follows:

[0150]

[0151] Substituting the value of u2 into the x in the membership functions B1, B2, and B3, we can obtain the membership vector R2 = {r 21 ,r 22 ,r 23};

[0152] The membership function of evaluation factor u3 to comment v1 is as follows:

[0153]

[0154] The membership function of evaluation factor u3 to comment v2 is as follows:

[0155]

[0156] The membership function of evaluation factor u3 to comment v3 is as follows:

[0157]

[0158] Substituting the value of u3 into the x in the membership functions C1, C2, and C3, we can obtain the membership vector R3 = {r 31 ,r 32 ,r 33};

[0159] The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3 ;

[0160]

[0161] (iv) determining the evaluation factor weight vector Q={q1,q2,q3}, where q1,q2,q3 represent the importance of the three evaluation factors u1,u2,u3, and q1+q2+q3=1. According to the test results, a fixed value Q={0.35,0.35,0.3} is taken in the embodiment;

[0162] (V) Calculate the comprehensive evaluation result S, and use matrix multiplication to calculate S=QR={s1,s2,s3}, where s1,s2,s3 represent the current evaluation factor set U={u1,u2,u3}. For the membership degree of each element v1,v2,v3 of the comment set V, take the maximum value among s1,s2,s3 to get the comprehensive comment of the current working condition; if s1 is the maximum value, give the comment v1: "good"; if s2 is the maximum value, give the comment v2: "qualified"; if s3 is the maximum value, give the comment v3: "poor" and issue an alarm.

[0163] Example 1

[0164] During a period of the production process, take the time period T = 5min, obtain the measured data t1 = 2846℃, t2 = 2850℃, w1 = 15.4Kg, w2 = 15.0Kg, p1 = 920Pa, p2 = 1370; calculate from the above data:

[0165]

[0166]

[0167]

[0168] Substituting u1=0.8 into x in the membership functions A1, A2, and A3, we obtain A1(x)=0.7, A2(x)=0.3, and A3(x)=0, i.e., the membership vector R1={0.7, 0.3, 0} of the evaluation factor u1;

[0169] Substituting u2=2.6 into x in the membership functions B1, B2, and B3, we obtain B1(x)=0.2, B2(x)=0.8, and B3(x)=0, i.e., the membership vector R2={0.2, 0.8, 0} of the evaluation factor u2;

[0170] Substituting u3=90 into the x in the membership functions C1, C2, and C3, we can obtain C1(x)=0, C2(x)=0.25, and C3(x)=0.75, respectively. That is, the membership vector of the evaluation factor u3 is R3={0,0.25,0.75}

[0171] The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3

[0172]

[0173] Take Q = {0.35, 0.35, 0.3} and calculate the comprehensive evaluation matrix S:

[0174]

[0175] Take the maximum value element s2=0.46 of the calculation result S and give the comment v2: "qualified".

[0176] Example 2

[0177] During a period of the production process, the time period is T = 5min, and the measured data are t1 = 2859°C, t2 = 2857°C, w1 = 16.4Kg, w2 = 16.1Kg, p1 = 1055Pa, p2 = 853Pa; calculated from the above data:

[0178]

[0179]

[0180]

[0181] Substitute u1=0.4 into x in the membership functions A1, A2, and A3 to obtain A1(x)=1, A2(x)=0, and A3(x)=0, respectively, that is, the membership vector R1={1,0,0} of the evaluation factor u1;

[0182] Substituting u2=1.8 into x in the membership functions B1, B2, and B3, we obtain B1(x)=0.6, B2(x)=0.4, and B3(x)=0, i.e., the membership vector R2={0.6, 0.4, 0} of the evaluation factor u2;

[0183] Substituting u3=40.4 into the x in the membership functions C1, C2, and C3, we obtain C1(x)=0.32, C2(x)=0.68, and C3(x)=0, that is, the membership vector of the evaluation factor u3 is R3={0.32, 0.68, 0}

[0184] The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3

[0185]

[0186] Take Q = {0.35, 0.35, 0.3}, and then calculate the comprehensive evaluation matrix S:

[0187]

[0188] Take the maximum value element s1=0.656 of the calculation result S and give the comment v1: "good".

[0189] Example 3

[0190] During a period of the production process, the time period is T = 5min, and the measured data are t1 = 2890℃, t2 = 2877℃, w1 = 16.2Kg, w2 = 15.4Kg, p1 = 865Pa, p2 = 1330Pa; calculated from the above data:

[0191]

[0192]

[0193]

[0194] Substituting u1=2.6 into x in the membership functions A1, A2, and A3, we obtain A1(x)=0, A2(x)=0.4, and A3(x)=0.6, i.e., the membership vector R1={0,0.4,0.6} of the evaluation factor u1;

[0195] Substituting u2=4.9 into x in the membership functions B1, B2, and B3, we obtain B1(x)=0, B2(x)=0.55, and B3(x)=0.45, i.e., the membership vector R2={0,0.55,0.45} of the evaluation factor u2;

[0196] Substituting u3=93 into x in the membership functions C1, C2, and C3, we can obtain C1(x)=0, C2(x)=0.175, and C3(x=0.825, respectively. That is, the membership vector of the evaluation factor u3 is R3={0,0.175,0.825}

[0197] The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3

[0198]

[0199] Take Q = {0.35, 0.35, 0.3}, and then calculate the comprehensive evaluation matrix S:

[0200]

[0201] Take the maximum value element s3=0.615 of the calculation result S, give a comment v3: "poor" and issue an alarm.

[0202] The technical solution provided by the present invention realizes the judgment of the operating condition of the material in the furnace based on the target temperature and pressure of the continuous graphitization and purification furnace cavity, the weight of the material entering the continuous graphitization and purification furnace, and the weight of the material discharged from the continuous graphitization and purification furnace, and then issues an alarm prompt for the operating condition of the continuous graphitization and purification furnace where the material flow is not smooth, thereby preventing and reducing the production risks such as material overheating and thermal balance out of control in the furnace, and improving product quality.

[0203] The present invention is not limited to the above preferred embodiments, and can also be transformed and improved in various forms within the spirit defined in the claims and the specification of the present invention, which can solve the same technical problems and achieve the expected technical effects, so it will not be repeated. All solutions that can be directly or associatively derived from the contents disclosed by ordinary technicians in the field, as long as they are within the spirit defined in the claims, also belong to the protection scope of the present invention.

Claims

1. A method for determining the stability of materials in a continuous graphitization and purification furnace, characterized in that: The following steps are involved: The infrared temperature measuring device detects the temperature of multiple measuring points in the continuous graphitization and purification furnace in real time and transmits it to the PLC in real time; The weighing device measures the weight of the material entering the continuous graphitization and purification furnace in real time, and measures the weight of the material discharged from the continuous graphitization and purification furnace in real time, and transmits it to the PLC in real time; The pressure sensor detects the gas pressure in the continuous graphitization and purification furnace in real time and transmits it to the PLC in real time; PLC comprehensively determines the stability of materials in the continuous graphitization and purification furnace based on three evaluation factors: temperature change rate, weight deviation rate, and pressure change rate in the continuous graphitization and purification furnace. The determination process is as follows: (I) Establish a set of evaluation factors U for comprehensive evaluation of material stability, including: 1) Temperature change rate u1: When the continuous graphitization and purification furnace is heated to the target temperature required by the process, the smaller the temperature change rate, the better the stability of the material in the furnace. PLC calculates the temperature change rate u1 according to the following formula Where t1 is the average temperature value detected at each measuring point at the beginning of the time period, in degrees Celsius t2 is the average temperature value detected at each measuring point at the end of the time period, in °C T is the time period, in min; 2) Weight deviation rate u2, the weight deviation rate is maintained at a small value, indicating that the material stability in the continuous graphitization and purification furnace is good, PLC calculates the weight deviation rate u2 according to the following formula Where w1 is the cumulative weight of materials input into the continuous graphitization and purification furnace during the time period, unit Kg w2 is the cumulative weight of the material output from the continuous graphitization and purification furnace during the time period, in kg; 3) Pressure change rate u3. The smaller the pressure change rate, the more the pressure in the furnace is in a dynamic equilibrium state and the better the material stability. PLC calculates the pressure change rate u3 according to the following formula Where p1 is the gas pressure detection value in the continuous graphitization and purification furnace at the beginning of the time period, in Pa p2 is the gas pressure detection value in the continuous graphitization and purification furnace at the end of the time period, in Pa T is the time period, in min; Thus, we obtain the evaluation factor set U = {u1, u2, u3}, i.e., the numerical combination of u1, u2, u3, corresponding to a specific working condition; (ii) Set the evaluation set V = {v1, v2, v3} = {good, qualified, poor} for each factor, and set the membership function of each evaluation factor to the evaluation set V. The membership is used to indicate the degree of conformity of a single factor to the evaluation, with a maximum value of 1 and a minimum value of 0; (III) Calculation of fuzzy comprehensive evaluation matrix R The membership function of evaluation factor u1 to comment v1 is as follows: The membership function of evaluation factor u1 to comment v2 is as follows: The membership function of evaluation factor u1 to comment v3 is as follows: Substituting the value of u1 into the x in the membership functions A1, A2, and A3, we can obtain the membership vector R1={r 11 ,r 12 ,r 13 }; The membership function of evaluation factor u2 to comment v1 is as follows: The membership function of evaluation factor u2 to comment v2 is as follows: The membership function of evaluation factor u2 to comment v3 is as follows: Substituting the value of u2 into the x in the membership functions B1, B2, and B3, we can obtain the membership vector R2 = {r 21 ,r 22 ,r 23 }; The membership function of evaluation factor u3 to comment v1 is as follows: The membership function of evaluation factor u3 to comment v2 is as follows: The membership function of evaluation factor u3 to comment v3 is as follows: Substituting the value of u3 into the x in the membership functions C1, C2, and C3, we can obtain the membership vector R3 = {r 31 ,r 32 ,r 33 }; The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3 ; (iv) Determine the evaluation factor weight vector Q = {q1, q2, q3}, where q1, q2, q3 represent the importance of the three evaluation factors u1, u2, u3, and q1+q2+q3=1; (V) Calculate the comprehensive evaluation result S, and use matrix multiplication to calculate S=QR={s1,s2,s3}, where s1,s2,s3 represent the current evaluation factor set U={u1,u2,u3}. For the membership degree of each element v1,v2,v3 of the comment set V, take the maximum value among s1,s2,s3 to get the comprehensive comment of the current working condition; if s1 is the maximum value, give the comment v1: "good"; if s2 is the maximum value, give the comment v2: "qualified"; if s3 is the maximum value, give the comment v3: "poor" and issue an alarm.

2. A system for determining the stability of materials in a continuous graphitization and purification furnace, comprising an infrared temperature measuring device, a weighing device, a pressure sensor, and a PLC electrically connected to the infrared temperature measuring device, the weighing device and the pressure sensor; characterized in that: The infrared temperature measuring device is used to collect the temperature of multiple measuring points in the continuous graphitization and purification furnace in real time and transmit it to the PLC in real time; The weighing device is used to measure the weight of the material entering the continuous graphitization and purification furnace in real time, and the weight of the material discharged from the continuous graphitization and purification furnace in real time, and transmit it to the PLC in real time; The pressure sensor is used to measure the gas pressure in the continuous graphitization and purification furnace in real time and transmit it to the PLC in real time; The PLC comprehensively determines the stability of the materials in the continuous graphitization and purification furnace based on the three evaluation factors of the temperature change rate, weight deviation rate, and pressure change rate in the continuous graphitization and purification furnace. The determination process is as follows: (I) Establish a set of evaluation factors U for comprehensive evaluation of material stability, including: 1) Temperature change rate u1: When the continuous graphitization and purification furnace is heated to the target temperature required by the process, the smaller the temperature change rate, the better the stability of the material in the furnace. PLC calculates the temperature change rate u1 according to the following formula Where t1 is the average temperature value detected at each measuring point at the beginning of the time period, in degrees Celsius t2 is the average temperature value detected at each measuring point at the end of the time period, in °C T is the time period, in min; 2) Weight deviation rate u2, the weight deviation rate is maintained at a small value, indicating that the material stability in the continuous graphitization and purification furnace is good, PLC calculates the weight deviation rate u2 according to the following formula Where w1 is the cumulative weight of materials input into the continuous graphitization and purification furnace during the time period, unit Kg w2 is the cumulative weight of the material output from the continuous graphitization and purification furnace during the time period, in kg; 3) Pressure change rate u3. The smaller the pressure change rate, the more the pressure in the furnace is in a dynamic equilibrium state and the better the material stability. PLC calculates the pressure change rate u3 according to the following formula Where p1 is the gas pressure detection value in the continuous graphitization and purification furnace at the beginning of the time period, in Pa p2 is the gas pressure detection value in the continuous graphitization and purification furnace at the end of the time period, in Pa T is the time period, in min; Thus, we obtain the evaluation factor set U = {u1, u2, u3}, i.e., the numerical combination of u1, u2, u3, corresponding to a specific working condition; (ii) Set the evaluation set V = {v1, v2, v3} = {good, qualified, poor} for each factor, and set the membership function of each evaluation factor to the evaluation set V. The membership is used to indicate the degree of conformity of a single factor to the evaluation, with a maximum value of 1 and a minimum value of 0; (III) Calculation of fuzzy comprehensive evaluation matrix R The membership function of evaluation factor u1 to comment v1 is as follows: The membership function of evaluation factor u1 to comment v2 is as follows: The membership function of evaluation factor u1 to comment v3 is as follows: Substituting the value of u1 into the x in the membership functions A1, A2, and A3, we can obtain the membership vector R1={r 11 ,r 12 ,r 13 }; The membership function of evaluation factor u2 to comment v1 is as follows: The membership function of evaluation factor u2 to comment v2 is as follows: The membership function of evaluation factor u2 to comment v3 is as follows: Substituting the value of u2 into the x in the membership functions B1, B2, and B3, we can obtain the membership vector R2 = {r 21 ,r 22 ,r 23 }; The membership function of evaluation factor u3 to comment v1 is as follows: The membership function of evaluation factor u3 to comment v2 is as follows: The membership function of evaluation factor u3 to comment v3 is as follows: Substituting the value of u3 into the x in the membership functions C1, C2, and C3, we can obtain the membership vector R3 = {r 31 ,r 32 ,r 33 }; The single factor membership vectors R1, R2, and R3 calculated above are rows, forming a 3-row and 3-column fuzzy comprehensive evaluation matrix R 3*3 ; (iv) Determine the evaluation factor weight vector Q = {q1, q2, q3}, where q1, q2, q3 represent the importance of the three evaluation factors u1, u2, u3, and q1+q2+q3=1; (V) Calculate the comprehensive evaluation result S, and use matrix multiplication to calculate S=QR={s1,s2,s3}, where s1,s2,s3 represent the current evaluation factor set U={u1,u2,u3}. For the membership degree of each element v1,v2,v3 of the comment set V, take the maximum value among s1,s2,s3 to get the comprehensive comment of the current working condition; if s1 is the maximum value, give the comment v1: "good"; if s2 is the maximum value, give the comment v2: "qualified"; if s3 is the maximum value, give the comment v3: "poor" and issue an alarm.

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