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

Abstract

The application provides a method and system for determining initial cracking temperature of poor residual oil, and belongs to the technical field of petroleum processing, and aims at the problem that the existing technology only relies on the secondary derivative of the DSC curve or the accuracy deficiency and lag problem that may occur when the thermal gravimetric analysis is performed, and a larger error exists in determination, and the method comprises the following steps: obtaining a differential scanning calorimetry curve and a thermal gravimetric 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-order derivative processing on the differential scanning calorimetry fitting curve to obtain a heat flow rate acceleration curve; determining a potential initial cracking temperature according to a minimum value point of the heat flow rate acceleration curve, screening the potential initial cracking temperature with a weight loss rate lower than 10% according to weight loss rate data of the thermal gravimetric analysis curve, and determining a final initial cracking temperature. The application solves the problem existing in the prior art, and improves the determination accuracy and efficiency of the initial cracking temperature of poor residual oil.

Description

Technical Field

[0001] This invention belongs to the field of petroleum processing technology, and in particular relates to a method and system for determining the initial cracking temperature of inferior residue oil. Background Technology

[0002] The statements in this section are merely 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 residue oil has become a key challenge for the refining industry. Low-quality residue oil, due to its high residual carbon and metal content, is prone to problems such as coking in furnace tubes and uneven product distribution during thermal conversion, seriously affecting the long-term stable operation of refining units. Therefore, accurately determining its initial cracking temperature is a core element in optimizing refining processes.

[0004] Currently, among existing cracking temperature determination technologies, traditional thermogravimetric analysis (TG) determines the cracking initiation point by monitoring the change in material mass with temperature during heating. However, the initial deterioration stage of inferior residue oil is often accompanied by a slow weight loss process, making it difficult to accurately locate the initiation point of the cracking reaction, resulting in a lag in the measurement results.

[0005] Furthermore, while differential scanning calorimetry (DSC) can directly detect changes in heat flow during temperature variations, residual oil undergoes simultaneous evaporation, phase change, and cracking endothermic effects during heating. Relying solely on the first-order heat flow curve of DSC only reflects the rate of heat flow change and cannot distinguish the superimposed effects of these processes. It also cannot accurately pinpoint the critical temperature point where the endothermic rate abruptly changes, leading to significant errors in determining the initial cracking temperature. Although the second derivative can highlight extreme values ​​of heat flow rate changes and filter out multiple possible cracking initiation temperature points, emphasizing abrupt changes in thermal effects through minimum points, relying solely on the second derivative of the DSC curve may mistakenly identify instrument noise or non-deteriorating endothermic effects as the reaction initiation point, resulting in significant errors in determining the initial cracking temperature. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, this invention provides a method and system for determining the initial cracking temperature of inferior residue oil. By utilizing the second derivative characteristics of the differential scanning calorimetry (DSC) curve and combining the weight loss data from the thermogravimetric analysis (TG) curve, the key temperature points of residue oil during thermal cracking can be accurately identified. This overcomes the inaccuracy and lag problems that may occur when relying solely on the second derivative of the DSC curve or thermogravimetric analysis in traditional methods. It can effectively improve the accuracy of temperature point identification during the thermal cracking process of residue oil, providing strong support for the thermal stability assessment of 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: The first aspect of this invention provides a method for determining the initial cracking temperature of inferior residue oil, comprising: Differential scanning calorimetry (DSC) curves and thermogravimetric analysis (TGA) curves of residual oil samples were obtained. Polynomial fitting was performed on the differential scanning calorimetry curve to obtain the denoised differential scanning calorimetry fitting curve. The second derivative of the denoised differential scanning calorimetry fitting curve is processed to obtain the heat flux rate of change acceleration curve. The potential initial cracking temperature is determined based on the minimum point of the heat flux rate acceleration curve; Based on the weight loss rate data from the thermogravimetric analysis curves, potential initial cracking temperatures with a weight loss rate below 10% are selected to determine the final initial cracking temperature.

[0008] As one implementation method, the differential scanning calorimetry (DSC) curve and thermogravimetric analysis (TGA) curve of the residual oil sample are obtained, and the specific process is as follows: The residual oil sample was dried, ground, pulverized, and homogenized, and a sample of a set mass was weighed as the test sample. Thermogravimetric-differential scanning calorimetry (TGC-DSC) was used to perform thermal analysis on the test samples, and differential scanning calorimetry (DSC) curves and thermogravimetric analysis (TGA) curves were obtained.

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

[0010] As one implementation method, the temperature range is set to 200°C to 500°C.

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

[0012] As one implementation method, the weight loss rate of the thermogravimetric analysis curve is calculated using the following formula: ; Where m0 is the initial mass, m T Let T be the remaining mass at temperature T.

[0013] As one implementation method, the heating rate of the thermogravimetric-differential scanning calorimeter is 10~20℃ / min, the temperature range is room temperature to 800℃, the purging 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 determining the initial cracking temperature of inferior residue oil, comprising: The thermal analysis module is used to acquire differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) 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; and to perform second derivative processing on the denoised differential scanning calorimetry fitting curve to obtain the heat flux 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 rate acceleration curve; and to screen the potential initial cracking temperatures with a weight loss rate of less than 10% based on the weight loss rate data of the thermogravimetric analysis curve, and to determine the final initial cracking temperature.

[0015] A third aspect of the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of a method as described in the first aspect of the present invention.

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

[0017] The above one or more technical solutions have the following beneficial effects: In this embodiment, by utilizing the second derivative characteristics of the differential scanning calorimetry (DSC) curve and combining it with the weight loss data from the thermogravimetric analysis (TG) curve, the inaccuracy and measurement lag issues that may occur when relying solely on the second derivative of the DSC curve or TG analysis in traditional methods are overcome. This effectively improves the accuracy of temperature point identification during the thermal cracking process of residue oil. The sensitive response of the second derivative of the DSC curve compensates for the inability of the TG curve to identify the characteristics of the initial stage of the cracking reaction, solving the problem of measurement lag. This allows for accurate determination of the cracking start-up temperature of residue oil and provides more scientific data support for the precise control of the cracking process in refining. This not only optimizes the cracking reaction process, extends the operating cycle, and improves energy utilization efficiency, but also optimizes the product distribution during the cracking process, thereby improving the quality of refined products, reducing energy consumption, and increasing efficiency.

[0018] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a flowchart of a method for determining the initial cracking temperature of inferior residue oil according to Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the first and second derivative curves of the DSC for inferior residual oil a in Embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the first and second derivative curves of the DSC for inferior residual oil b in Embodiment 1 of the present invention. Figure 4 This is a schematic diagram of the first and second derivative curves of the DSC for inferior residual oil c in Embodiment 1 of the present invention. Figure 5 This is a schematic diagram of the DSC curve of inferior residue oil a in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the TG curve of inferior residue oil a in Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the TG curve of inferior residue oil b in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the TG curve of inferior residue oil c in Embodiment 1 of the present invention. Detailed Implementation

[0021] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0023] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0024] Example 1 This embodiment discloses a method for determining the initial cracking temperature of inferior residue oil, including: S1. Obtain the differential scanning calorimetry curve and thermogravimetric analysis curve of the residue oil sample; S2. Perform polynomial fitting on the differential scanning calorimetry curve to obtain the denoised differential scanning calorimetry fitting curve; perform second derivative processing on the denoised differential scanning calorimetry fitting curve to obtain the heat flux change rate acceleration curve. S3. Determine the potential initial cracking temperature based on the minimum point of the heat flow rate acceleration curve; based on the weight loss rate data of the thermogravimetric analysis curve, screen potential initial cracking temperatures with a weight loss rate of less than 10%, and determine the final initial cracking temperature.

[0025] To illustrate this embodiment more clearly, we will take inferior residual oil samples a, b, and c as examples.

[0026] First, let's take the inferior residual oil sample a as an example.

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

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

[0029] Specifically, the inferior residue oil dried in a forced-air drying oven was ground and pulverized to ensure uniform particle size. Approximately 7.1 mg of the inferior residue oil sample a was weighed as the test sample, and the initial sample mass was accurately recorded.

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

[0031] Specifically, the inferior residue oil sample a underwent TG-DSC testing and analysis. The weighed sample of inferior residue oil a was placed in a thermogravimetric-differential scanning calorimeter (TG-DSC). The heating program started at room temperature and increased to 800℃ at a rate of 10℃ / min. During this process, the changes in sample mass and heat flow were recorded in real time. Finally, the differential scanning calorimetry (DSC) curve and thermogravimetric analysis (TG) curve of the residue oil a sample were obtained, as shown below. Figure 5 , Figure 6 As shown.

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

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

[0034] In this embodiment, polynomial fitting of the differential scanning calorimetry (DSC) curve is performed by performing 5th to 9th order polynomial fitting 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 a temperature range of 200℃ to 500℃, the differential scanning calorimetry (DSC) curve of residue oil sample a was subjected to a 6th-order polynomial fitting process to obtain the denoised differential scanning calorimetry fitting curve of residue oil sample a.

[0037] The above steps effectively remove noise and fluctuations in the heat flow signal, thereby improving data accuracy.

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

[0039] Specifically, the first and second derivatives of the differential scanning calorimetry fitting curve of residue oil sample a were processed to obtain the rate curve of heat flux change with steady-state conditions and the acceleration curve of the rate of change of heat flux, as shown below. Figure 2 As shown.

[0040] This processing method allows for further analysis of the details of heat flow changes.

[0041] like Figure 1 As shown, in step S3, the potential initial cracking temperature is determined based on the minimum point of the heat flow rate acceleration curve; based on the weight loss rate data of the thermogravimetric analysis curve, potential initial cracking temperatures with a weight loss rate of less than 10% are 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 rate of change of heat flux acceleration curve reflects the speed of change of the heat flux rate, and its minimum point corresponds to the critical point where the rate of heat flux change changes from a slow increase to a rapid increase. Therefore, the minimum point must be determined first, and then the potential initial cracking temperature can be determined based on the minimum point.

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

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

[0046] The absolute value of the rate of change of the endothermic rate corresponding to the minimum point is greater than twice the 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℃.

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

[0048] Specifically, based on the analysis results, 305℃ and 424℃ were determined to be the two minimum points on the rate of change of heat flux acceleration curve of residue oil sample a, and these were taken as the potential initial cracking temperatures of residue oil sample a. The corresponding weight loss rates were 1.41% and 16.38%, respectively.

[0049] The above steps can accurately capture the starting point of the cracking reaction, 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 potential initial cracking temperatures with a weight loss rate of less than 10% and determine the final initial cracking temperature.

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

[0052] Where m0 is the initial mass, m T Let T be the remaining mass at temperature T.

[0053] (2) Determine the final initial cracking temperature and screen the effective cracking temperature. Comparing the weight loss rates (1.41% and 16.38%) corresponding to the potential initial cracking temperatures (305℃ and 424℃), the temperature point with a weight loss rate below 10% was selected as the effective cracking initiation temperature. 305℃ (weight loss rate 1.41% < 10%) meets the characteristics of the initial stage of cracking (slight volatilization or decomposition of light components). 424℃ (weight loss rate 16.38% > 10%) belongs to the significant cracking stage and is excluded from the initial cracking determination.

[0054] By combining the minimum point of the rate of change of heat flow acceleration with the weight loss data of the thermogravimetric analysis (TG) curve, 305℃ was finally determined as the initial cracking temperature of the inferior residue oil sample a.

[0055] By following the above steps, the effects of intense cracking or noise interference in the high-temperature zone can be eliminated, and the starting temperature of the cracking reaction can be accurately identified, providing key parameters for the thermal conversion process of residue oil.

[0056] Based on the characteristics of weight loss rate changes in the 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%, so the initial cracking temperature of inferior residue oil sample a is 305℃.

[0057] Table 1. Analysis of characteristic temperatures and weight loss rates of thermal pyrolysis in residue oil samples.

[0058] In this embodiment, a method for determining the initial cracking temperature based on multi-parameter synergistic analysis was successfully established. By comprehensively analyzing the DSC heat flow change characteristics and TG weight loss rate data, the initial cracking temperature of the inferior residue oil sample a was scientifically determined to be 305℃. This temperature point not only satisfies the minimum characteristic of the heat flow rate acceleration curve but also meets the mass change standard of a weight loss rate of less than 10%, 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 inferior residue oil sample b was determined according to steps S1 to S3.

[0061] The specific process is as follows: (1) Grind and pulverize the inferior residue oil that has been dried in a forced-air drying oven to ensure uniform particle size. Weigh approximately 5.4 mg of the inferior residue oil sample b, 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 heating program started at room temperature and increased to 800℃ at a rate of 10℃ / 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 sample b were obtained. The thermogravimetric analysis (TG) curve is shown below. Figure 7 As shown.

[0063] (2) Within the temperature range of 200℃ to 500℃, the differential scanning calorimetry (DSC) curve of residue oil sample b was subjected to sixth-order polynomial fitting to obtain the noise-reduced differential scanning calorimetry fitting curve of residue oil sample b.

[0064] (3) The first and second derivatives of the differential scanning calorimetry fitting curve of residue oil sample b after denoising were processed respectively to obtain the rate curve of heat flux change with steady state and the acceleration curve of heat flux change rate of residue oil sample b, as shown in the figure. Figure 3 As shown.

[0065] (4) Further analysis of the thermal flow rate acceleration curve of residue oil sample b revealed that 331℃ was a minimum point on the curve and was taken as the potential initial cracking temperature, with a corresponding weight loss rate of 6.71%. Based on the weight loss rate data from the thermogravimetric analysis curve, i.e., the initial decomposition temperature of inferior heavy oil is within the temperature range where its mass loss is less than 10%, the initial cracking temperature of inferior residue oil sample b can be determined to be 331℃, as shown in Table 1.

[0066] Again, let's take the inferior residual oil sample C as an example.

[0067] The initial cracking temperature of the inferior residue oil sample c was determined according to steps S1 to S3.

[0068] The specific process is as follows: (1) Grind and pulverize the inferior residue oil that has been dried in a forced-air drying oven to ensure uniform particle size. Weigh approximately 5.6 μm of the inferior residue oil sample c, accurately record the initial sample mass, and perform TG-DSC analysis.

[0069] The weighed sample was placed in a TG-DSC apparatus. The heating program started at room temperature and increased to 800℃ at a rate of 10℃ / 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 sample b were obtained. The thermogravimetric analysis (TG) curve is shown below. Figure 8 As shown.

[0070] (2) Within the temperature range of 200℃ to 500℃, the differential scanning calorimetry (DSC) curve of residue oil sample c was subjected to sixth-order polynomial fitting to obtain the noise-reduced differential scanning calorimetry fitting curve of residue oil sample c.

[0071] (3) The first and second derivatives of the differential scanning calorimetry fitting curve of the residue oil sample c after denoising were processed respectively to obtain the rate curve of heat flux change with steady state and the acceleration curve of heat flux change rate, as shown in the figure. Figure 4 As shown.

[0072] (4) Further analysis of the thermal flux change rate acceleration curve of residue oil sample c revealed that 273℃ and 407℃ were the minimum points of the thermal flux change rate acceleration curve, which were taken as the potential initial cracking temperatures, with corresponding weight loss rates of 0.71% and 11.05%, respectively. Based on the weight loss rate data from the thermogravimetric analysis curve, i.e., the initial decomposition temperature of inferior heavy oil is within the temperature range where its mass loss is less than 10%, the initial cracking temperature of inferior residue oil sample c can be determined to be 273℃, as shown in Table 1.

[0073] In this embodiment, firstly, significant temperature points indicating changes in heat flux rate are analyzed using the second derivative of the differential scanning calorimetry (DSC) curve, identifying multiple potential thermal cracking initiation temperatures. Then, these temperature points are combined with TG analysis results, and the key temperature points identified by DSC are further validated and optimized using the weight loss characteristics of the TG curve, ultimately determining the optimal initiation temperature for thermal cracking, thereby more accurately assessing the thermal stability of the residue oil. This method overcomes the accuracy limitations that may arise when relying solely on DSC curve analysis in traditional methods, especially when dealing with the diverse thermal effects during complex thermal cracking processes.

[0074] Example 2 The purpose of this embodiment is to provide a system for determining the initial cracking temperature of inferior residue oil, including: The thermal analysis module is used to acquire differential scanning calorimetry (DSC) curves and thermogravimetric analysis (TGA) curves 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; and to perform second derivative processing on the denoised differential scanning calorimetry fitting curve to obtain the heat flux 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 rate acceleration curve; and to screen the potential initial cracking temperatures with a weight loss rate of less than 10% based on the weight loss rate data of the thermogravimetric analysis curve, and to determine the final initial cracking temperature.

[0075] The method steps in Example 1 are implemented based on a system for determining the initial cracking temperature of inferior residual oil.

[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 executes the program to implement the steps of the above-described method.

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

[0078] A computer-readable storage medium having a computer program stored thereon, 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 that, when run on a computer, cause the computer to perform the methods and functions involved in any of the above embodiments. The steps and methods involved in the apparatus of the above embodiments correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0080] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0081] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this 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 without creative effort based on the technical solutions of the present invention 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: Differential scanning calorimetry (DSC) curves and thermogravimetric analysis (TGA) curves of residual oil were obtained; Polynomial fitting is performed on the differential scanning calorimetry curve to obtain the denoised differential scanning calorimetry fitting curve. The second derivative of the denoised differential scanning calorimetry fitting curve is processed to obtain the heat flux change rate acceleration curve. The potential initial cracking temperature is determined based on the minimum point of the aforementioned heat flux rate of change acceleration curve; Based on the weight loss rate data from the thermogravimetric analysis curves, potential initial cracking temperatures with a weight loss rate below 10% are selected to determine the final initial cracking temperature.

2. The method for determining the initial cracking temperature of inferior residual oil as described in claim 1, characterized in that, The differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) curves for the residual oil were obtained as follows: The residual oil sample was dried, ground, pulverized, and homogenized, and a sample of a set mass was weighed as the test sample. The test sample was thermally analyzed using a thermogravimetric-differential scanning calorimeter to obtain differential scanning calorimetry curves and thermogravimetric analysis curves.

3. The method for determining the initial cracking temperature of inferior residual oil as described in claim 1, characterized in that, Polynomial fitting is performed on the differential scanning calorimetry curve. Specifically, within a set temperature range, the differential scanning calorimetry curve is subjected to 5th to 9th order polynomial fitting to obtain a denoised differential scanning calorimetry fitting curve.

4. The method for determining the initial cracking temperature of inferior residual oil as described in claim 3, characterized in that, The set temperature range is 200℃ to 500℃.

5. The method for determining the initial cracking temperature of inferior residual oil as described in claim 1, characterized in that, The potential initial cracking temperature is determined based on the minimum point of the heat flux change rate acceleration curve. The specific process is as follows: The minimum point of the heat flux rate of change acceleration curve is determined by numerical differentiation algorithm, and the heat absorption rate corresponding to the minimum point exceeds a set threshold. The minimum point is used as the potential initial cracking temperature.

6. The method for determining the initial cracking temperature of inferior residue oil as described in claim 1, characterized in that, The weight loss rate of the thermogravimetric analysis curve is calculated using the following formula: ； Where m0 is the initial mass, m T Let T be the remaining mass at temperature T.

7. The method for determining the initial cracking temperature of inferior residue oil as described in claim 2, characterized in that, The heating rate of the thermogravimetric-differential scanning calorimeter is 10~20℃ / min, the temperature range is room temperature to 800℃, the purging gas is high-purity nitrogen, and the flow rate is 25~50 mL / min.

8. A system for determining the initial cracking temperature of inferior residue oil, characterized in that, include: The thermal analysis module is used to acquire differential scanning calorimetry (DSC) curves and thermogravimetric analysis (TGA) curves 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; and to perform second derivative processing on the denoised differential scanning calorimetry fitting curve to obtain a heat flux 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 rate acceleration curve; and to screen the potential initial cracking temperatures with a weight loss rate of less than 10% based on the weight loss rate data of the thermogravimetric analysis curve, and 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, characterized in that, When the processor executes the program, it implements the steps of the method for determining the initial cracking temperature of inferior residue oil as described in any one of claims 1-7.

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

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