Method and system for measuring initial cracking temperature of inferior residual oil

Abstract

The invention provides a method and a system for measuring the initial cracking temperature of inferior residual oil, belongs to the technical field of petroleum processing, and aims to solve the problems that in the prior art, the accuracy is insufficient and lagging possibly occurs when only a DSC curve secondary derivative is depended on or thermogravimetric analysis exists, and the judgment has a relatively large error. Comprising the following steps: acquiring a differential scanning calorimetry curve and a thermogravimetric analysis curve of residual oil, performing polynomial fitting on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve, and performing second derivative processing on the denoised differential scanning calorimetry fitting curve to obtain a heat flow change rate acceleration curve; and determining the potential initial cracking temperature according to the minimum value point, screening the potential initial cracking temperature of which the weight loss ratio is lower than 10% according to the weight loss ratio data of the thermogravimetric analysis curve, and determining the final initial cracking temperature. According to the method, the problems in the prior art are solved, and the measurement precision and efficiency of the initial cracking temperature of the inferior residual oil are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum processing, and in particular relates to a method and a system for measuring the initial cracking temperature of inferior residual oil. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In the petroleum processing sector, the efficient conversion of heavy crude oil and low-quality residual oil has become a key challenge for the refining industry. Due to the high residual carbon and metal content of low-quality residual oil, it is easy to cause problems such as coking in furnace tubes and uneven product distribution during the thermal conversion process, seriously affecting the long-term stable operation of the refining unit. Therefore, accurately measuring the initial cracking temperature is a key step in optimizing the refining process.

[0004] Among existing cracking temperature measurement technologies, traditional thermogravimetric analysis (TG) determines the cracking onset by monitoring the change in material mass with temperature during heating. However, the initial degradation of low-quality residual oil is often accompanied by a slow weight loss process, making it difficult to accurately locate the onset of the cracking reaction, resulting in a lag in measurement results.

[0005] Furthermore, while differential scanning calorimetry (DSC) can directly measure changes in heat flow during temperature changes, residual oil experiences simultaneous endothermic effects from evaporation, phase change, and cracking during heating. Relying solely on the DSC first-order heat flow curve can only reflect the rate of heat flow change, failing to distinguish the combined effects of these processes and accurately pinpoint the critical temperature point at which the endothermic rate suddenly changes, resulting in significant errors in determining the initial cracking temperature. While the second-order derivative can highlight extreme values of heat flow rate changes, screen out multiple possible cracking onset temperatures, and highlight sudden changes in thermal effects through minimum values, relying solely on the second-order derivative of the DSC curve can mistakenly identify instrument noise or non-degradation endothermic effects as the reaction starting point, leading to significant errors in determining the initial cracking temperature. Summary of the Invention

[0006] To overcome the shortcomings of the above-mentioned prior art, the present invention provides a method and system for determining the initial cracking temperature of inferior residue oil. By combining the second-order derivative characteristics of the differential scanning calorimetry (DSC) curve with the weight loss data of the thermogravimetric analysis (TG) curve, the key temperature points of the residue oil during the thermal cracking process can be accurately identified. This overcomes the inaccuracy and hysteresis problems that may occur when traditional methods rely solely on the second-order derivative of the DSC curve or thermogravimetric analysis. It can effectively improve the accuracy of temperature point identification during the thermal cracking process of the residue oil, providing strong support for the thermal stability assessment of the residue oil and the optimization of the refining process.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: A first aspect of the present invention provides a method for determining the initial cracking temperature of inferior residual oil, comprising: Obtain differential scanning calorimetry curves and thermogravimetric analysis curves of residual oil samples; Perform polynomial fitting on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve; The de-noised differential scanning calorimetry fitting curve was processed by second-order derivative to obtain the heat flow rate acceleration curve. The potential initial cracking temperature is determined according to the minimum point of the heat flow rate acceleration curve; According to the weight loss rate data of the thermogravimetric analysis curve, the potential initial cracking temperature with a weight loss rate lower than 10% is screened to determine the final initial cracking temperature.

[0008] As an embodiment, a differential scanning calorimetry curve and a thermogravimetric analysis curve of a residual oil sample are obtained, and the specific process is as follows: The residual oil sample is dried, ground, crushed and evenly processed, and a sample of a set mass is weighed as a test sample; The test samples were thermally analyzed using a thermogravimetric-differential scanning calorimeter to obtain differential scanning calorimetry curves and thermogravimetric analysis curves.

[0009] As an implementation method, a polynomial fitting is performed on the differential scanning calorimetry curve. Specifically, within a set temperature range, a 5th to 9th order polynomial fitting process is performed on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve.

[0010] As an embodiment, the set temperature range is 200°C to 500°C.

[0011] As an implementation method, the potential initial cracking temperature is determined based on the minimum point of the heat flow rate acceleration curve. The specific process is as follows: The minimum point of the heat flux change rate acceleration curve is determined by numerical differentiation algorithm, and the heat absorption rate corresponding to the minimum point exceeds the set threshold; The minimum point is taken as the potential initial cracking temperature.

[0012] As an embodiment, the weight loss rate of the thermogravimetric analysis curve is calculated as follows: ; Among them, m0 is the initial mass, m T is the residual mass at temperature T.

[0013] As an embodiment, the heating rate of the thermogravimetric-differential scanning calorimeter is 10-20°C / min, the temperature rise range is room temperature to 800°C, the purge gas is high-purity nitrogen, and the flow rate is 25-50 mL / min.

[0014] A second aspect of the present invention provides a system for measuring the initial cracking temperature of inferior residual oil, comprising: Thermal analysis module, used to obtain differential scanning calorimetry curves and thermogravimetric analysis curves of residual oil samples; The data processing module is used to perform polynomial fitting on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve; perform second-order derivative processing on the denoised differential scanning calorimetry fitting curve to obtain a heat flow change rate acceleration curve; The temperature measurement module is used to determine the potential initial cracking temperature based on the minimum point of the heat flow change rate acceleration curve; based on the weight loss rate data of the thermogravimetric analysis curve, screen the potential initial cracking temperature with a weight loss rate lower than 10% to determine the final initial cracking temperature.

[0015] The third aspect of the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps in a method as described in the first aspect of the present invention are implemented.

[0016] A fourth aspect of the present invention provides a computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps of a method as described in the first aspect of the present invention.

[0017] One or more of the above technical solutions have the following beneficial effects: In this example, the second-order derivative characteristics of the differential scanning calorimetry (DSC) curve, combined with weight loss data from the thermogravimetric analysis (TG) curve, overcome the inaccuracies and measurement lag associated with conventional methods that rely solely on the second-order derivative of the DSC curve or thermogravimetric analysis. This effectively improves the accuracy of temperature point identification during the thermal cracking process of residual oil. The sensitive response of the second-order derivative of the DSC curve overcomes the difficulty of the TG curve in identifying the characteristics of the initial cracking reaction, and addresses the lag in measurement results. This allows accurate determination of the residual oil's cracking start-up temperature and provides more scientific data support for precise control of the cracking process in the refinery. This approach not only optimizes the cracking reaction, extends the production cycle, and improves energy efficiency, but also optimizes the product distribution during the cracking process, thereby improving the quality of refined products, reducing energy consumption, and increasing profitability.

[0018] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0020] Figure 1 This is a flow chart of a method for determining the initial cracking temperature of inferior residual oil according to Example 1 of the present invention; Figure 2 Schematic diagram of DSC first-order derivative and second-order derivative curves of low-quality residue oil a according to Example 1 of the present invention; Figure 3 Schematic diagram of DSC first-order derivative and second-order derivative curves of low-quality residual oil b according to Example 1 of the present invention; Figure 4 Schematic diagram of DSC first-order derivative and second-order derivative curves of low-quality residual oil c according to Example 1 of the present invention; Figure 5 Schematic diagram of the DSC curve of low-quality residual oil a according to Example 1 of the present invention; Figure 6 This is a schematic diagram of the TG curve of the low-quality residue oil a according to Example 1 of the present invention; Figure 7 This is a schematic diagram of the TG curve of the inferior residue oil b according to Example 1 of the present invention; Figure 8 Schematic diagram of the TG curve of the inferior residue oil c according to Example 1 of the present invention. DETAILED DESCRIPTION

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0022] It should be noted that the terms used herein are for describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present invention.

[0023] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0024] Example 1 This embodiment discloses a method for determining the initial cracking temperature of low-quality residual oil, comprising: S1. Obtaining a differential scanning calorimetry curve and a thermogravimetric analysis curve of a residual oil sample; S2. Performing polynomial fitting on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve; performing second-order derivative processing on the denoised differential scanning calorimetry fitting curve to obtain a heat flow change rate acceleration curve; S3. Determine the potential initial cracking temperature based on the minimum point of the heat flow change rate acceleration curve; based on the weight loss rate data of the thermogravimetric analysis curve, screen the potential initial cracking temperature with a weight loss rate lower than 10% to determine the final initial cracking temperature.

[0025] In order to illustrate this embodiment more clearly, low-quality residual oil samples a, b and c are taken as examples.

[0026] First, take the low-quality residual oil sample a as an example.

[0027] like Figure 1 As shown, in step S1, a differential scanning calorimetry curve and a thermogravimetric analysis curve of the residual oil sample are obtained.

[0028] In this embodiment, the specific process is: (1) Dry, grind and evenly treat the residual oil sample, and weigh a set mass of sample as the test sample.

[0029] Specifically, the inferior residual oil dried in a blast drying oven was ground and pulverized to ensure uniform sample particles. About 7.1 mg of the inferior residual oil a sample was weighed as a test sample, and the initial sample mass was accurately recorded.

[0030] (2) The test samples were thermally analyzed using a thermogravimetric-differential scanning calorimeter to obtain differential scanning calorimetry curves and thermogravimetric analysis curves.

[0031] Specifically, the low-quality residue oil a sample was subjected to TG-DSC testing and analysis. The weighed low-quality residue oil a sample was placed in a thermogravimetric-differential scanning calorimeter (TG-DSC). The temperature was raised from room temperature to 800°C at a heating rate of 10°C / min. During this process, the mass change and heat flow change of the sample were recorded in real time, and the differential scanning calorimetry (DSC) curve and thermogravimetric analysis (TG) curve of the residue oil a sample were finally obtained, as shown in Figure 2. Figure 5 、 Figure 6 shown.

[0032] like Figure 1 As shown, in step S2, a polynomial fitting is performed on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve; and a second-order derivative processing is performed on the denoised differential scanning calorimetry fitting curve to obtain a heat flow change rate acceleration curve.

[0033] S2-1. Perform polynomial fitting on the differential scanning calorimetry curve to obtain a de-noised differential scanning calorimetry fitting curve.

[0034] In this embodiment, the differential scanning calorimetry (DSC) curve is subjected to polynomial fitting by performing 5th to 9th order polynomial fitting processing on the differential scanning calorimetry curve within a set temperature range to obtain a denoised differential scanning calorimetry fitting curve.

[0035] Furthermore, a 6th order polynomial is preferred.

[0036] Specifically, within the temperature range of 200° C. to 500° C., a sixth-order polynomial fitting process is performed on the differential scanning calorimetry (DSC) curve of the residue oil a sample to obtain a denoised differential scanning calorimetry fitting curve of the residue oil a sample.

[0037] After the above steps, the noise and fluctuation of the heat flow signal summary can be effectively removed, thereby improving the accuracy of the data.

[0038] S2-2. Perform second-order derivative processing on the de-noised differential scanning calorimetry fitting curve to obtain the heat flow change rate acceleration curve.

[0039] Specifically, the first-order derivative and second-order derivative processing of the differential scanning calorimetry fitting curve of the residue oil sample a after denoising were performed to obtain the rate curve of heat flow with stable change and the acceleration curve of heat flow change rate, as shown in Figure 2 shown.

[0040] Through this processing method, the details of the heat flow changes can be further analyzed.

[0041] like Figure 1 As shown, in step S3, the potential initial cracking temperature is determined according to the minimum point of the heat flow change rate acceleration curve; according to the weight loss rate data of the thermogravimetric analysis curve, the potential initial cracking temperature with a weight loss rate lower than 10% is screened to determine the final initial cracking temperature.

[0042] S3-1. Determine the potential initial cracking temperature based on the minimum point of the heat flow rate acceleration curve.

[0043] In this example, the second-derivative heat flux rate acceleration curve reflects the speed of the heat flux change rate, and its minimum corresponds to the critical point where the heat flux rate changes from a slow increase to a rapid increase. Therefore, it is necessary to first determine the minimum point and then use it to determine the potential initial cracking temperature.

[0044] The specific process for determining the potential initial cracking temperature is: (1) The minimum point of the heat flux change rate acceleration curve is determined by numerical differentiation algorithm, and the heat absorption rate corresponding to the minimum point exceeds the set threshold.

[0045] Specifically, the minimum point of the acceleration curve of the heat flux change rate is determined by derivation of Savitzky-Golay filtering, and the filter window width is 7-11 data points.

[0046] The absolute value of the change rate of the heat absorption rate corresponding to the minimum point is greater than twice the peak-to-peak value of the baseline noise, where the baseline noise is taken from the second derivative fluctuation data of the differential scanning calorimetry (DSC) curve in the temperature range of 50-200°C.

[0047] (2) Determine the temperature value corresponding to the minimum point, that is, the potential initial cracking temperature.

[0048] Specifically, the analysis identified 305°C and 424°C as the two minimum points in the heat flow rate acceleration curve for Residue A, respectively, and used these as the potential cracking onset temperatures. The corresponding weight loss rates were 1.41% and 16.38%, respectively.

[0049] After the above steps, the starting point of the cracking reaction can be accurately captured, directly reflecting the triggering moment of the cracking reaction with high sensitivity.

[0050] S3-2. Based on the weight loss rate data of the thermogravimetric analysis curve, screen the potential initial cracking temperature with a weight loss rate lower than 10% and determine the final initial cracking temperature.

[0051] In this embodiment, the specific process of determining the final initial cracking temperature is as follows: (1) Extracting weight loss rate data Read the remaining percentage of sample mass corresponding to each temperature point from the thermogravimetric analysis (TG) curve and calculate the weight loss (WL):

[0052] Among them, m0 is the initial mass, m T is the residual mass at temperature T.

[0053] (2) Determine the final initial cracking temperature and screen the effective cracking temperature Comparing the corresponding weight loss rates (1.41% and 16.38%) for potential initial cracking temperatures (305°C and 424°C), the temperature with a weight loss below 10% was selected as the effective cracking onset temperature. 305°C (weight loss 1.41% < 10%) corresponds to the initial stage of cracking (slight volatilization or decomposition of light components). 424°C (weight loss 16.38% > 10%) corresponds to the significant cracking stage, eliminating the possibility of initial cracking.

[0054] Combining the minimum point of the heat flow rate acceleration and the weight loss rate data of the thermogravimetric analysis (TG) curve, it was finally determined that 305℃ was the initial cracking temperature of the inferior residue oil sample a.

[0055] After the above steps, the influence of violent cracking or noise interference in the high-temperature zone can be eliminated, the starting temperature of the cracking reaction can be accurately identified, and key parameters can be provided for the residual oil thermal conversion process.

[0056] According to the changing characteristics of weight loss rate of thermogravimetric analysis (TG) curve, such as Figure 6 As shown in Table 1, the initial decomposition temperature of inferior heavy oil is within the temperature range where its mass loss is less than 10%. It can be concluded that the initial cracking temperature of inferior residue oil sample a is 305℃.

[0057] Table 1 Analysis of thermal cracking characteristic temperature and weight loss rate of residual oil samples

[0058] In this example, a method for determining the initial cracking temperature based on multi-parameter collaborative analysis was successfully established. By integrating DSC heat flow characteristics and TG weight loss data, the initial cracking temperature of low-quality residue oil sample a was scientifically determined to be 305°C. This temperature point not only meets the minimum characteristic of the heat flow rate acceleration curve but also meets the quality change standard of less than 10% weight loss, ensuring the reliability and repeatability of the analysis results.

[0059] Secondly, take the inferior residual oil sample b as an example.

[0060] The initial cracking temperature of the low-quality residue oil b sample is measured according to steps S1 to S3.

[0061] The specific process is: (1) Grind the low-quality residual oil dried in a blast drying oven to ensure uniform sample particles. Weigh approximately 5.4 mg of the low-quality residual oil b sample, accurately record the initial sample mass, and perform TG-DSC analysis.

[0062] The weighed sample was placed in a thermogravimetric-differential scanning calorimeter (TG-DSC). The temperature was raised from room temperature to 800°C at a rate of 10°C / min. During this process, the mass change and heat flow change of the sample were recorded in real time. Finally, the differential scanning calorimetry (DSC) curve and thermogravimetric analysis (TG) curve of the residue oil b sample were obtained. The thermogravimetric analysis (TG) curve is shown in Figure 2. Figure 7 shown.

[0063] (2) In the temperature range of 200℃ to 500℃, the differential scanning calorimetry (DSC) curve of the residue oil sample b was fitted with a sixth-order polynomial to obtain the denoised differential scanning calorimetry fitting curve of the residue oil sample b.

[0064] (3) The first-order derivative and second-order derivative processing of the differential scanning calorimetry fitting curve of the residue oil b sample after denoising were performed respectively to obtain the rate curve of the heat flow of the residue oil b sample with stable change and the acceleration curve of the heat flow change rate, as shown in Fig. Figure 3 shown.

[0065] (4) Further analysis of the heat flow rate acceleration curve for residue oil sample b identified 331°C as a minimum point on the curve, corresponding to a weight loss rate of 6.71%. Based on the weight loss data from the thermogravimetric analysis curve, indicating that the initial decomposition temperature of low-quality heavy oil lies within the temperature range where its mass loss is less than 10%, it can be concluded that the initial cracking temperature of low-quality residue oil sample b is 331°C, as shown in Table 1.

[0066] Again, take the low-quality residual oil sample c as an example.

[0067] The initial cracking temperature of the low-quality residue oil c sample is measured according to steps S1 to S3.

[0068] The specific process is: (1) Grind the low-quality residual oil dried in a blast drying oven to ensure uniform sample particles. Weigh approximately 5.6 μm of the low-quality residual oil c sample, accurately record the initial sample mass, and perform TG-DSC testing and analysis.

[0069] The weighed sample was placed in a TG-DSC, and the temperature was raised from room temperature to 800°C at a rate of 10°C / min. During this process, the mass change and heat flow change of the sample were recorded in real time, and the differential scanning calorimetry (DSC) curve and thermogravimetric analysis (TG) curve of the residue oil b sample were finally obtained. The thermogravimetric analysis (TG) curve is shown in Figure 2. Figure 8 shown.

[0070] (2) In the temperature range of 200℃ to 500℃, the differential scanning calorimetry (DSC) curve of the residue oil c sample was fitted with a sixth-order polynomial to obtain the denoised differential scanning calorimetry fitting curve of the residue oil c sample.

[0071] (3) The first-order derivative and second-order derivative processing of the differential scanning calorimetry fitting curve of the residue oil c sample after denoising were performed respectively to obtain the rate curve of the heat flow of the residue oil c sample with stable change and the acceleration curve of the heat flow change rate, as shown in Fig. Figure 4 shown.

[0072] (4) Further analysis of the heat flow rate acceleration curve for residue oil sample c identified 273°C and 407°C as the minimum points of the heat flow rate acceleration curve, respectively, as potential cracking initial temperatures, with corresponding weight loss rates of 0.71% and 11.05%, respectively. Based on the weight loss data from the thermogravimetric analysis curve, indicating that the initial decomposition temperature of low-quality heavy oil is within the temperature range where its mass loss is less than 10%, it can be concluded that the initial cracking temperature of low-quality residue oil sample c is 273°C, as shown in Table 1.

[0073] In this example, the second derivative of the differential scanning calorimetry (DSC) curve was first used to analyze significant temperature points of heat flow rate changes, identifying multiple potential thermal cracking onset temperatures. These temperature points were then combined with TG analysis results, and the weight loss characteristics of the TG curve were used to further validate and optimize the key temperature points identified by DSC. Ultimately, the optimal thermal cracking onset temperature was determined, resulting in a more accurate assessment of the thermal stability of the residual oil. This method overcomes the potential inaccuracies of traditional methods that rely solely on DSC curve analysis, especially in the complex thermal cracking process with diverse thermal effects.

[0074] Example 2 The purpose of this embodiment is to provide a system for measuring the initial cracking temperature of low-quality residual oil, comprising: Thermal analysis module, used to obtain differential scanning calorimetry curve and thermogravimetric analysis curve of residual oil; The data processing module is used to perform polynomial fitting on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve; perform second-order derivative processing on the denoised differential scanning calorimetry fitting curve to obtain a heat flow change rate acceleration curve; The temperature measurement module is used to determine the potential initial cracking temperature based on the minimum point of the heat flow change rate acceleration curve; based on the weight loss rate data of the thermogravimetric analysis curve, screen the potential initial cracking temperature with a weight loss rate lower than 10% to determine the final initial cracking temperature.

[0075] Based on providing a system for measuring the initial cracking temperature of inferior residual oil, the method steps in Example 1 are implemented.

[0076] Example 3 The purpose of this embodiment is to provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the program.

[0077] Example 4 The purpose of this embodiment is to provide a computer-readable storage medium.

[0078] A computer-readable storage medium stores a computer program, which, when executed by a processor, performs the steps of the above method.

[0079] Example 5 The purpose of this embodiment is to provide a computer program product containing instructions, which, when running on a computer, enables the computer to execute the methods and functions involved in any of the above embodiments. The steps involved in the apparatus of the above embodiment correspond to those of the method embodiment 1. For detailed implementation, please refer to the relevant description of embodiment 1. The term "computer-readable storage medium" should be understood to mean a single medium or multiple media containing one or more instruction sets; it should also be understood to include any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and causing the processor to perform any method of the present invention.

[0080] Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using a general-purpose computer device. Alternatively, they can be implemented using program code executable by a computing device, which can then be stored in a storage device and executed by the computing device. Alternatively, they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0081] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A method for determining the initial cracking temperature of inferior residual oil, characterized in that: include: Obtain differential scanning calorimetry curve and thermogravimetric analysis curve of residual oil; Performing polynomial fitting on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve; Performing second-order derivative processing on the de-noised differential scanning calorimetry fitting curve to obtain a heat flow change rate acceleration curve; determining a potential initial cracking temperature according to a minimum value point of the heat flow change rate acceleration curve; According to the weight loss rate data of the thermogravimetric analysis curve, the potential initial cracking temperature with a weight loss rate lower than 10% is screened to determine the final initial cracking temperature.

2. The method for measuring the initial cracking temperature of low-quality residual oil according to claim 1, wherein: The differential scanning calorimetry curve and thermogravimetric analysis curve of the residual oil are obtained by the following process: The residual oil sample is dried, ground, crushed and evenly processed, and a sample of a set mass is weighed as a test sample; The test sample was thermally analyzed using a thermogravimetric-differential scanning calorimeter to obtain a differential scanning calorimetry curve and a thermogravimetric analysis curve.

3. The method for measuring the initial cracking temperature of low-quality residual oil according to claim 1, wherein: The differential scanning calorimetry curve is subjected to polynomial fitting. Specifically, within a set temperature range, the differential scanning calorimetry curve is subjected to polynomial fitting of order 5 to 9 to obtain a de-noised differential scanning calorimetry fitting curve.

4. The method for measuring the initial cracking temperature of low-quality residual oil according to claim 3, wherein: The set temperature range is 200°C to 500°C.

5. The method for measuring the initial cracking temperature of low-quality residual oil according to claim 1, wherein: The potential initial cracking temperature is determined according to the minimum point of the heat flow change rate acceleration curve. The specific process is as follows: Determine the minimum point of the heat flux change rate acceleration curve by a numerical differentiation algorithm, and the heat absorption rate corresponding to the minimum point exceeds a set threshold; The minimum point is taken as the potential initial cracking temperature.

6. The method for determining the initial cracking temperature of low-quality residual oil according to claim 1, wherein: The weight loss rate of the thermogravimetric analysis curve is calculated as follows: ； Among them, m0 is the initial mass, m T is the residual mass at temperature T.

7. The method for measuring the initial cracking temperature of low-quality residual oil according to claim 2, wherein: The heating rate of the thermogravimetric-differential scanning calorimeter is 10-20°C / min, the temperature rise range is from room temperature to 800°C, and the purge gas is high-purity nitrogen with a flow rate of 25-50 mL / min.

8. A system for measuring the initial cracking temperature of low-quality residual oil, characterized in that: include: Thermal analysis module, used to obtain differential scanning calorimetry curve and thermogravimetric analysis curve of residual oil; a data processing module, configured to perform polynomial fitting on the differential scanning calorimetry curve to obtain a denoised differential scanning calorimetry fitting curve; and perform second-order derivative processing on the denoised differential scanning calorimetry fitting curve to obtain a heat flow rate acceleration curve; The temperature measurement module is used to determine the potential initial cracking temperature according to the minimum point of the heat flow change rate acceleration curve; based on the weight loss rate data of the thermogravimetric analysis curve, screen the potential initial cracking temperature with a weight loss rate lower than 10% to determine the final initial cracking temperature.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the steps of the method for determining the initial cracking temperature of inferior residual oil as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method for determining the initial cracking temperature of inferior residual oil as described in any one of claims 1 to 7 are performed.

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