Method for determining low-carbon olefin latent yield index of hydrocarbon-based raw material and method for selecting hydrocarbon-based raw material with high yield of low-carbon olefin

Abstract

The invention relates to a method for determining a low-carbon olefin latent yield index of a hydrocarbon-based raw material and a method for selecting a hydrocarbon-based raw material with high yield of low-carbon olefin. Comprising the following steps: S1, enabling a target alkyl raw material to enter a gas chromatography-mass spectrometry analysis system for analysis treatment to obtain mass-to-charge ratio distribution data of the target alkyl raw material; s2, the characteristic peak intensity corresponding to the characteristic mass-to-charge ratio of the target alkyl raw material is obtained according to the mass-to-charge ratio distribution data, the numerical values of the characteristic mass-to-charge ratio include 41 + 14n and 43 + 14n, and n is 0, 1, 2, 3, 4 and 5 respectively; and S3, calculating according to the following formula to obtain the low-carbon olefin latent yield index LOI: # imgabs0 # of the target alkyl raw material. The method is small in sampling amount, and a system used for analysis is simple, convenient and rapid and is low in cost.

Description

Technical Field

[0001] The present application relates to the field of petrochemical industry, and in particular, to a method for determining a low-carbon olefin potential yield index of a hydrocarbon-based feedstock and a method for selecting a hydrocarbon-based feedstock that can produce more low-carbon olefins. Background Art

[0002] Low-carbon olefins such as ethylene, propylene, and butene are important basic organic chemical raw materials. They are mainly used as monomers for the production of three major synthetic materials. They are also widely used as raw materials for organic synthesis such as oxygen-containing chemicals, halides, nitrile derivatives and other fine chemicals, pharmaceuticals and dye intermediates. The advanced level of production technology, output and equipment scale of low-carbon olefins such as ethylene and propylene are one of the indicators to measure the strength of a country's petrochemical industry. In addition, against the backdrop of a slowdown in the growth of refined oil consumption and a structural overcapacity in refining capacity, adjusting part of the excess refining capacity to the production capacity of chemicals such as low-carbon olefins is an important measure to resolve the structural contradiction of refining capacity and improve the economic benefits of refineries. At present, the production technologies of low-carbon olefins include steam cracking, catalytic cracking, alkane dehydrogenation, olefin conversion and methanol to olefins, but the main route is still steam cracking and catalytic cracking of hydrocarbon-based raw materials.

[0003] At present, the main cost of refineries comes from crude oil, which generally accounts for more than 60% of the total cost. Secondly, for steam cracking and catalytic cracking processes, the properties and composition of the raw materials have a crucial impact on the yield of their light olefin products. Therefore, evaluating and optimizing the potential yield of raw materials for producing light olefins is beneficial to the refinery to reduce costs, maximize the potential of raw materials, and improve the yield of target products, thereby improving the overall economic benefits. At present, the potential of hydrocarbon-based raw materials to produce light olefins is mainly indirectly evaluated based on macroscopic properties such as characteristic factors K value and hydrogen content. Xie Chaogang et al. introduced the results of catalytic thermal cracking of raw oils with different properties to produce olefins in the article "Research on the Preparation of Ethylene and Propylene by Catalytic Thermal Cracking of Heavy Oil" (Petroleum Refining and Chemical Industry, 1994, 25 (6): 30-34), indicating that the larger the characteristic factor K value of the raw material, that is, the stronger the paraffin property of the raw material, the higher the yield of ethylene and propylene. J. Knight et al. of UOP used hydrogen content to evaluate the performance of FCC feedstock in producing propylene in the article "Maximize propylene from your FCC unit" {Hydrocarbon Processing, Issue 9, Pages 91-95 (2011)}, and believed that there was a positive correlation between propylene yield and feedstock hydrogen content. In addition, Cai Xinheng et al. constructed a propylene potential yield model and index based on the molecular composition data of heavy oil combined with the chemical rules of catalytic cracking reaction in the article "Heavy Oil Propylene Potential Yield Model and Application Based on Molecular Characterization" (Petroleum and Natural Gas Chemical Engineering, 2020, 49 (4): 56-61). The actual catalytic cracking propylene yield and low-carbon olefin yield both increase accordingly with the increase of the feedstock propylene potential yield index. However, this method relies on molecular composition data and requires a combination of multiple mass spectrometers for analysis, which is costly and relatively time-consuming. Summary of the invention

[0004] The purpose of the present disclosure is to provide a method for determining the low-carbon olefin potential yield index of hydrocarbon-based feedstocks and a method for selecting hydrocarbon-based feedstocks that produce more low-carbon olefins. The method has a small sampling volume, a simple and fast analysis system, and low cost.

[0005] In order to achieve the above-mentioned object, the present disclosure provides a method for determining the low-carbon olefin latent yield index LOI of a hydrocarbon-based feedstock in a first aspect, comprising the following steps:

[0006] S1, allowing the target hydrocarbon-based raw material to enter a gas chromatography-mass spectrometry analysis system for analysis and processing to obtain mass-to-charge ratio distribution data of the target hydrocarbon-based raw material;

[0007] S2. Obtaining characteristic peak intensity corresponding to the characteristic mass-to-charge ratio of the target hydrocarbon-based raw material according to the mass-to-charge ratio distribution data, wherein the values ​​of the characteristic mass-to-charge ratio include 41+14n and 43+14n, and n is 0, 1, 2, 3, 4 and 5 respectively;

[0008] S3. Calculate the low-carbon olefin potential yield index LOI of the target hydrocarbon-based feedstock according to the following formula (1):

[0009]

[0010] Where, (m / z) k represents the value of the kth characteristic mass-to-charge ratio among all characteristic mass-to-charge ratios represented by 41+14n and 43+14n in step S2, I (m / z)k represents the characteristic peak intensity corresponding to the kth characteristic mass-to-charge ratio, I (m / z)i It represents the peak intensity corresponding to the i-th mass-to-charge ratio among all the spectral peaks corresponding to the mass-to-charge ratios within the scanning range of the mass spectrometry analysis spectrum. Int is the rounding operator.

[0011] Optionally, the characteristic peak intensity corresponding to the characteristic mass-to-charge ratio includes: the maximum value of the intensity of the spectrum peak within the range of ±0.5Da of the characteristic mass-to-charge ratio.

[0012] Optionally, the target hydrocarbon-based raw material includes one or more of straight-run petroleum fractions and hydrogenation products thereof, atmospheric residue oil, vacuum residue oil and hydrogenation products thereof, Fischer-Tropsch synthetic oil and hydrogenation products thereof, deasphalted oil and hydrogenation products thereof, coal tar and hydrogenation products thereof, and waste plastic pyrolysis oil and hydrogenation products thereof.

[0013] Optionally, the method further comprises:

[0014] Before step S1, sampling the hydrocarbon-based feedstock or mixing the hydrocarbon-based feedstock with a solvent to obtain the target hydrocarbon-based feedstock;

[0015] Optionally, when the hydrocarbon-based raw material is mixed with a solvent, the amount of the solvent used is 0.01 to 0.1 ml, preferably 0.02 to 0.05 ml, per mg of the hydrocarbon-based raw material;

[0016] Optionally, the solvent is selected from one or more of n-pentane, n-hexane, n-heptane, dichloromethane and toluene.

[0017] Optionally, the method further comprises:

[0018] The target hydrocarbon-based raw material is subjected to ultrasonic oscillation treatment and then introduced into a gas chromatography-mass spectrometry analysis system.

[0019] Optionally, the ultrasonic oscillation treatment conditions include: ultrasonic frequency of 15 to 40 KHz, ultrasonic power of 1000 to 4000 W, and treatment time of 10 to 30 min.

[0020] Optionally, the gas chromatograph in the gas chromatography-mass spectrometry analysis system uses a capillary column with an upper temperature limit in the range of 350-400°C; the capillary column does not contain a stationary phase membrane or the capillary column contains 100% methyl polysiloxane, or the capillary column contains a non-polar bonded stationary phase membrane.

[0021] Optionally, the mass-to-charge ratio scanning mode of the mass spectrometer in the gas chromatography-mass spectrometry analysis system is full scan, the value of the initial mass-to-charge ratio is 10-42; and an EI ionization source is used.

[0022] Optionally, the acquisition conditions of the gas chromatography-mass spectrometry analysis system include: the temperature of the injection port is 320-400°C; the injection volume is 0.1-2 μL, the initial temperature of the chromatographic column box is 30-100°C, the temperature is increased to 300-400°C at a rate of 20-40°C / min, and the temperature is maintained at the final temperature section for 5-15 min, the temperature of the gas chromatography and mass spectrometry transmission line is 300-400°C, the mass spectrometry tuning mode is standard spectrum tuning, the electron bombardment energy is 10-70 eV, and the solvent delay is 0-3 min;

[0023] Preferably, the temperature of the injection port is 320-350°C; the injection volume is 0.5-1 μL, the initial temperature of the chromatographic column box is 30-50°C, the temperature is increased to 320-350°C at a rate of 30-40°C / min, and maintained in the final temperature section for 7-10 min, the gas chromatography and mass spectrometry transmission line temperature is 320-340°C, the mass spectrometry electron bombardment energy is 50-70 eV, and the solvent delay is 2.5-3 min.

[0024] The second aspect of the present disclosure provides a method for selecting a hydrocarbon-based feedstock that produces more low-carbon olefins, comprising the following steps:

[0025] According to the method described in the first aspect of the present disclosure, respectively determine the light olefin potential yield index LOI of multiple target hydrocarbon-based feedstocks;

[0026] The obtained multiple low-carbon olefin potential yield indexes LOI are used to determine the ability of the multiple target hydrocarbon-based raw materials to produce more low-carbon olefins in order of numerical value, wherein the larger the low-carbon olefin potential yield index LOI is, the stronger the ability of the target hydrocarbon-based raw material to produce more low-carbon olefins is.

[0027] Through the above technical scheme, the present disclosure provides a method for determining the low-carbon olefin potential yield index of hydrocarbon-based raw materials and a method for selecting hydrocarbon-based raw materials with high yield of low-carbon olefins. The method uses the mass-to-charge ratio distribution data of the mass spectrometry analysis of the target hydrocarbon-based raw materials, and uses a specific characteristic mass-to-charge ratio and its corresponding peak intensity according to formula (1) to calculate the low-carbon olefin potential yield index of the target hydrocarbon-based raw materials, thereby reflecting the potential of the target hydrocarbon-based raw materials to produce high-carbon olefins; the present disclosure constructs a low-carbon olefin potential yield index to directly evaluate and optimize hydrocarbon-based raw materials, without using the extraction separation, detailed molecular composition analysis, element determination, density determination, distillation cutting and other processes commonly used in existing schemes, solving the limitation of the existing technology relying on large-scale high-resolution mass spectrometry, nuclear magnetic resonance or ACE test equipment, or only indirectly judging the quality of hydrocarbon-based raw materials by physical property combination parameters. In addition, the method disclosed in the present disclosure has a small sampling volume, a simple and fast analysis system, low cost, and a good linear correlation between the method result and the actual yield, which is particularly suitable for the analysis requirements of the process of high yield of low-carbon olefins for hydrocarbon-based raw material screening, raw material hydroprocessing and upgrading effect evaluation, and cracking raw material expansion and substitution evaluation.

[0028] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0030] Figure 1 The total ion current diagram of the straight-run vacuum gas oil obtained in Example 1;

[0031] Figure 2 This is the EI mass spectrum of the straight-run vacuum wax oil obtained in Example 1;

[0032] Figure 3 It is a linear correlation diagram of the low-carbon olefin potential yield index of the straight-run vacuum gas oil obtained in Example 1 and the actual propylene yield and (ethylene+propylene) yield of catalytic cracking;

[0033] Figure 4 The figure is a linear correlation diagram of the low-carbon olefin potential yield index of the hydrocracking tail oil obtained in Example 2 and the actual propylene yield and (ethylene+propylene) yield of catalytic cracking;

[0034] Figure 5 The figure is a linear correlation diagram of the low-carbon olefin potential yield index of the intermediate base wax oil raw material and its hydrogenation and upgrading product obtained in Example 3 and the actual propylene yield and (ethylene + propylene) yield of catalytic cracking;

[0035] Figure 6The figure is a linear correlation diagram of the low-carbon olefin potential yield index of the intermediate base hydrogenated residue obtained in Example 4 and the actual propylene yield and (ethylene+propylene) yield of catalytic cracking;

[0036] Figure 7 It is a linear correlation diagram of the low-carbon olefin potential yield index of the three vacuum wax oils obtained in Comparative Example 1 and the actual propylene yield and (ethylene + propylene) yield of catalytic cracking. DETAILED DESCRIPTION

[0037] The specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0038] The first aspect of the present disclosure provides a method for determining a low-carbon olefin latent yield index LOI of a hydrocarbon-based feedstock, comprising the following steps:

[0039] S1, allowing the target hydrocarbon-based raw material to enter a gas chromatography-mass spectrometry analysis system for analysis and processing to obtain mass-to-charge ratio distribution data of the target hydrocarbon-based raw material;

[0040] S2. Obtaining characteristic peak intensity corresponding to the characteristic mass-to-charge ratio of the target hydrocarbon-based raw material according to the mass-to-charge ratio distribution data, wherein the values ​​of the characteristic mass-to-charge ratio include 41+14n and 43+14n, and n is 0, 1, 2, 3, 4 and 5 respectively;

[0041] S3. Calculate the low-carbon olefin potential yield index LOI of the target hydrocarbon-based feedstock according to the following formula (1):

[0042]

[0043] Where, (m / z) k represents the value of any characteristic mass-to-charge ratio among all characteristic mass-to-charge ratios represented by 41+14n and 43+14n in step S2, I (m / z)k Indicates the mass-to-charge ratio (m / z) k The corresponding characteristic peak intensity, I (m / z)i It represents the peak intensity corresponding to the i-th mass-to-charge ratio among all the spectral peaks corresponding to the mass-to-charge ratios within the scanning range of the mass spectrometry analysis spectrum. Int is the rounding operator.

[0044] The present disclosure provides a method for determining the low-carbon olefin potential yield index of a hydrocarbon-based raw material. The method uses the mass-to-charge ratio distribution data of the mass spectrometry analysis of the target hydrocarbon-based raw material, and uses a specific characteristic mass-to-charge ratio and its corresponding peak intensity according to formula (1) to calculate the low-carbon olefin potential yield index of the target hydrocarbon-based raw material, thereby reflecting the potential of the target hydrocarbon-based raw material to produce more low-carbon olefins; the present disclosure constructs a low-carbon olefin potential yield index to directly evaluate and optimize the hydrocarbon-based raw material, without using the extraction separation, detailed molecular composition analysis, element determination, density determination, distillation cutting and other processes commonly used in existing schemes, solving the limitation of the existing technology relying on large-scale high-resolution mass spectrometry, nuclear magnetic resonance or ACE test equipment, or only indirectly judging the quality of hydrocarbon-based raw materials through physical property combination parameters. In addition, the method disclosed in the present disclosure has a small sampling volume, a simple and fast analysis system, low cost, and a good linear correlation between the method result and the actual yield, which is particularly suitable for the analysis requirements of the process of high-yield low-carbon olefin screening of hydrocarbon-based raw materials, evaluation of the effect of raw material hydroprocessing and upgrading, and evaluation of cracking raw material expansion and substitution.

[0045] In the present disclosure, the values ​​of the characteristic mass-to-charge ratio include 41+14n and 43+14n, where n is 0, 1, 2, 3, 4 and 5 respectively, that is, the characteristic mass-to-charge ratio includes 41, 55, 69, 83, 97 and 111, and 43, 57, 71, 85, 99 and 113, totaling 12 values.

[0046] The present disclosure determines the peak intensity of the characteristic peak corresponding to each mass-to-charge ratio (including 12 characteristic mass-to-charge ratios) within the scanning range by obtaining a data table corresponding to the mass spectrum, wherein the acquisition source of the data table corresponding to the mass spectrum is well known to those skilled in the art.

[0047] In a specific embodiment, the characteristic peak intensity corresponding to the characteristic mass-to-charge ratio includes: the maximum value of the intensity of the spectrum peak within the range of ±0.5Da of the characteristic mass-to-charge ratio. This embodiment can also be determined according to the data table corresponding to the mass spectrum.

[0048] In one embodiment, the target hydrocarbon-based raw material includes one or more of straight-run petroleum fractions and their hydrogenation products, atmospheric residue oil, vacuum residue oil and their hydrogenation products, Fischer-Tropsch synthetic oil and their hydrogenation products, deasphalted oil and their hydrogenation products, coal tar and their hydrogenation products, and waste plastic pyrolysis oil and their hydrogenation products.

[0049] In one embodiment, the method further comprises:

[0050] Before step S1, the hydrocarbon-based feedstock is sampled or mixed with a solvent to obtain the target hydrocarbon-based feedstock. In the present disclosure, the hydrocarbon-based feedstock can be directly sampled according to actual needs, or the hydrocarbon-based feedstock can be mixed with a solvent and used as a sample.

[0051] In a specific embodiment, when the hydrocarbon-based raw material is mixed with the solvent, the amount of the solvent used is 0.01 to 0.1 ml, preferably 0.02 to 0.05 ml, per mg of the hydrocarbon-based raw material;

[0052] Optionally, the solvent is selected from one or more of n-pentane, n-hexane, n-heptane, dichloromethane and toluene.

[0053] In one embodiment, the method further comprises:

[0054] The target hydrocarbon-based raw material is subjected to ultrasonic oscillation treatment and then introduced into a gas chromatography-mass spectrometry analysis system. Ultrasonic oscillation is beneficial to improving the dispersibility of the hydrocarbon-based raw material and the accuracy of subsequent tests.

[0055] In a specific implementation manner, the ultrasonic oscillation treatment conditions include: ultrasonic frequency of 15 to 40 KHz, ultrasonic power of 1000 to 4000 W, and treatment time of 10 to 30 min.

[0056] In one embodiment, the temperature of the gas chromatograph injection port in the gas chromatography-mass spectrometry analysis system is 320-400°C, preferably 320-350°C; a capillary chromatographic column with low bleed and an upper temperature limit in the range of 350-400°C is used; the capillary chromatographic column does not contain a stationary phase membrane or the capillary chromatographic column contains 100% methyl polysiloxane, or the capillary chromatographic column contains a non-polar bonded stationary phase membrane. The capillary chromatographic columns used in the present disclosure can all be purchased through common commercial channels.

[0057] In one embodiment, the mass-to-charge ratio scanning mode of the mass spectrometer in the gas chromatography-mass spectrometry analysis system is full scan, and the starting mass-to-charge ratio value is 10 to 42, preferably 35; an EI ionization source is used; optionally, the ending mass number of the mass-to-charge ratio scanning range of the mass spectrometer is 600 to 700.

[0058] In one embodiment, the acquisition conditions of the gas chromatography-mass spectrometry analysis system include: an injection volume of 0.1 to 2 μL, an initial temperature of the chromatographic column box of 30 to 100° C., a temperature increase of 40° C. / min to 300 to 400° C., and a maintenance of 5 to 15 min in the final temperature section, a gas chromatography and mass spectrometry transmission line temperature of 300 to 400° C., a mass spectrometry tuning mode of standard spectrum tuning, an electron bombardment energy of 10 to 70 eV, and a solvent delay of 0 to 3 min;

[0059] Preferably, the injection volume is 0.5-1 μL, the initial temperature of the chromatographic column box is 30-50°C, the temperature is increased to 320-350°C at a rate of 30-40°C / min, and maintained in the final temperature section for 7-10 min. The temperature of the gas chromatography and mass spectrometry transmission line is 320-340°C, the mass spectrometry electron bombardment energy is 50-70 eV, and the solvent delay is 2.5-3.0 min.

[0060] The second aspect of the present disclosure provides a method for selecting a hydrocarbon-based feedstock that produces more low-carbon olefins, comprising the following steps:

[0061] According to the method described in the first aspect of the present disclosure, respectively determine the light olefin potential yield index LOI of multiple target hydrocarbon-based feedstocks;

[0062] The obtained multiple low-carbon olefin potential yield indexes LOI are used to determine the ability of the multiple target hydrocarbon-based raw materials to produce more low-carbon olefins in order of numerical value, wherein the larger the low-carbon olefin potential yield index LOI is, the stronger the ability of the target hydrocarbon-based raw material to produce more low-carbon olefins is.

[0063] The present disclosure provides a method for selecting hydrocarbon-based raw materials that produce more light olefins. The method obtains the light olefin potential yield index LOI of multiple target hydrocarbon-based raw materials, and then reflects the potential of multiple target hydrocarbon-based raw materials to produce light olefins according to the order of the light olefin potential yield index LOI, so as to compare and select the advantages and disadvantages of hydrocarbon-based raw materials for producing light olefins.

[0064] According to the present disclosure, for hydrocarbon-based raw materials with different low-carbon olefin potential yield indexes, if the processing conditions such as steam cracking and catalytic cracking are the same, the hydrocarbon-based raw material with a high low-carbon olefin potential yield index will have a higher actual yield of propylene and (ethylene + propylene), that is, the hydrocarbon-based raw material that can produce more low-carbon olefins is preferred.

[0065] The present disclosure is further described in detail by way of examples. The raw materials used in the examples can all be obtained through commercial sources.

[0066] Example 1

[0067] This example collects EI mass spectrum data of hydrocarbon raw materials, calculates the low-carbon olefin potential yield index and performs verification.

[0068] (1) Preparation of hydrocarbon-based raw material samples to be tested

[0069] For the three straight-run vacuum wax oils of paraffin, intermediate and cycloalkyl, the three straight-run vacuum wax oils were melted into uniform liquids in a 100°C infrared oven. For each straight-run vacuum wax oil, 80 μL of sample was aspirated with a pipette and placed in a 2 mL chromatographic vial. Further, 1000 μL of dichloromethane was aspirated with a pipette and added to the chromatographic vial to dissolve the sample (the amount of solvent was 0.03 mL per mg of hydrocarbon raw material), and three target hydrocarbon raw materials were obtained, which were recorded as vacuum wax oils A to C.

[0070] (2) Collecting EI mass spectrometry data of hydrocarbon-based raw materials

[0071] The EI mass spectrometric data of three vacuum wax oil samples (target hydrocarbon-based raw materials) were collected using an Agilent 7890-5975 gas chromatograph-mass spectrometer. The instrument was configured with a 7693 autosampler, a Xinnuo quartz capillary chromatographic empty column (40m×0.25mm, temperature upper limit 400°C) and an electron impact (EI) ionization source.

[0072] The collection method was as follows: the injection port temperature was 350°C, the injection volume was 1 μL, the initial temperature of the chromatographic column box was 50°C, maintained for 3 min, heated to 350°C at a rate of 40°C / min, and maintained at the final temperature for 7 min. The gas chromatography and mass spectrometry transmission line temperature was 330°C, the mass spectrometry tuning mode was standard spectrum tuning, the electron bombardment energy was 70 eV, the mass-to-charge ratio full scan range was 35-700, and the solvent delay was 2.5 min.

[0073] (3) Calculate and verify the low-carbon olefin potential yield index of hydrocarbon-based feedstocks

[0074] After collecting the total ion currents of the three vacuum wax oil samples (the total ion current of vacuum wax oil A is shown in the attached figure), Figure 1 ), and converted into an EI mass spectrum using GC-MS data analysis software (the EI mass spectrum of vacuum wax oil A is shown in the attached Figure 2 As shown), and the mass-to-charge ratio distribution and mass spectrum peak intensity distribution data of the EI mass spectrum are read. Further, the mass-to-charge ratios 41+14n and 43+14n (n is 0, 1, 2, 3, 4, 5, a total of 12 characteristic mass-to-charge ratios) and the maximum peak intensity within the range of ±0.5Da of these mass-to-charge ratios are selected (acquired according to the data in the mass spectrum table, and the characteristic peak intensity values ​​corresponding to the 12 characteristic mass-to-charge ratios of the three raw materials are listed in Table 1 below) as the input for calculating the low-carbon olefin potential yield index LOI of the hydrocarbon-based raw material.

[0075] The low-carbon olefin potential yield index of each target hydrocarbon-based feedstock is calculated according to the following formula (1):

[0076]

[0077] Where, (m / z) k represents the value of any mass-to-charge ratio among all characteristic mass-to-charge ratios calculated by 41+14n and 43+14n in step S2, I (m / z)k The charge-to-mass ratio is expressed as (m / z) k The corresponding characteristic peak intensity, I (m / z)i It represents the peak intensity corresponding to any mass-to-charge ratio within the scanning range of the mass spectrometry analysis spectrum. Int is the rounding operator.

[0078] The calculated low-carbon olefin potential yield index of the three vacuum wax oils and their catalytic cracking actual propylene yield and (ethylene + propylene) yield are compared with the relative advantages and disadvantages of the trend and are listed in the following Table 2.

[0079] The reaction conditions of the three straight run vacuum gas oil catalytic cracking reaction zones are: reaction temperature 620℃, space velocity 4h -1 The amount of atomizing steam (in terms of the weight ratio of fresh raw materials) is 25% by weight. The catalytic cracking reaction device is a conventional structure in the art.

[0080] Table 1

[0081] (m / z) Vacuum Wax Oil A Vacuum wax oil B Vacuum wax oil C 41 64892.0 47162.5 37055.5 43 145669.9 86547.1 60820.6 55 108206.0 85543.6 68778.2 57 233498.7 118180.1 82201.6 69 75705.6 67040.6 58036.9 71 133956.7 64282.6 43692.1 83 71605.2 49776.9 38251.0 85 101417.9 45648.0 31028.4 97 78516.3 53050.6 39483.4 99 34098.8 16561.7 10883.2 111 46971.4 35321.7 27454.0 113 23450.8 12203.2 8670.6

[0082] Table 2

[0083]

[0084] Note: * refers to the actual yield under the same process conditions in a small fixed fluidized bed reactor.

[0085] Figure 3 The linear correlation diagram of the low carbon olefin potential yield index of the straight run vacuum gas oil obtained by the method of the present disclosure and the actual propylene yield and (ethylene + propylene) yield of catalytic cracking is shown in Table 2 and Table 3. Figure 3 It can be seen that the relative order of the low-carbon olefin potential yield index and the actual yield of low-carbon olefins of the three vacuum gas oils is A>B>C. The method provided by the present disclosure can accurately identify the relative advantages and disadvantages of the potential of vacuum gas oils of different genera to produce propylene and low-carbon olefins, and the linear correlation between the low-carbon olefin potential yield index and the actual yield is good (R 2 >0.9), indicating that the method provided by the present disclosure can be used for the optimization and quantitative prediction of hydrocarbon-based feedstocks that produce more light olefins.

[0086] Example 2

[0087] Using the same steps as in Example 1, for three kinds of hydrocracking tail oils (hydrocracking tail oils D to F), the relative advantages and disadvantages of the low-carbon olefin potential yield index of the three kinds of hydrocracking tail oils calculated and analyzed and compared with their actual propylene yields and (ethylene + propylene) yields by catalytic cracking are shown in Table 3.

[0088] The reaction conditions of the catalytic cracking reaction zone of the three hydrocracking tail oils are: reaction temperature 620℃, space velocity 4h -1 The amount of atomizing steam (in terms of the weight ratio of fresh raw materials) is 25% by weight. The catalytic cracking reaction device is a conventional structure in the art.

[0089] Table 3

[0090]

[0091] Note: * refers to the actual yield under the same process conditions in a small fixed fluidized bed reactor.

[0092] Figure 4The figure is a linear correlation diagram of the low carbon olefin potential yield index of the hydrocracking tail oil obtained by the method disclosed in the present invention and the actual propylene yield and (ethylene + propylene) yield of catalytic cracking. Figure 4 It can be seen that the relative order of the low-carbon olefin potential yield index and the actual yield of low-carbon olefins of the three types of hydrocracking tail oils is D>E>F. The method disclosed in the present invention can reflect the relative advantages and disadvantages of the potential of producing propylene and low-carbon olefins from hydrocracking tail oils from different sources, and the linear correlation between the low-carbon olefin potential yield index and the actual yield is good.

[0093] Example 3

[0094] For intermediate base wax oil and its hydrogenation products:

[0095] (1) Preparation of hydrocarbon-based raw material samples to be tested

[0096] Weigh about 50 mg of intermediate wax oil G and its hydrogenation reformed products H~I samples respectively and place them in 2 mL chromatographic vials. Use a pipette to draw 1000 μL of n-hexane into the chromatographic vials to dissolve the samples (the amount of solvent is 0.02 ml for each milligram of hydrocarbon-based raw material). Further treat with an ultrasonic oscillator with a frequency of 40 kHz and a power of 100 W for 15 minutes before analysis.

[0097] (2) Collecting EI mass spectrometry data of hydrocarbon-based raw materials

[0098] The EI mass spectrometric data of the intermediate base wax oil and its hydrogenation product samples were collected using an Agilent 7890-5975 gas chromatograph-mass spectrometer. The instrument was configured with a 7693 autosampler, a CP7491 Agilent Select Mineral Oil capillary column (15m×0.32mm×0.1um, upper temperature limit 400°C) and an electron impact (EI) ionization source.

[0099] The collection method was as follows: the injection port temperature was 350°C, the injection volume was 1 μL, the initial temperature of the chromatographic column box was 50°C, maintained for 3 min, heated to 350°C at a rate of 40°C / min, and maintained at the final temperature for 10 min. The gas chromatography and mass spectrometry transmission line temperature was 340°C, the mass spectrometry tuning mode was standard spectrum tuning, the electron bombardment energy was 70 eV, the mass-to-charge ratio full scan range was 10-700, and the solvent delay was 3 min.

[0100] (3) The same data processing and calculation steps as in Example 1 are used to calculate the low-carbon olefin potential yield index of the intermediate base wax oil and its hydrogenation and upgrading products.

[0101] The relative advantages and disadvantages of the calculated low-carbon olefin potential yield index of the intermediate base wax oil and its hydrogenation modification products and the actual propylene yield and (ethylene + propylene) yield of their catalytic cracking are compared in Table 4.

[0102] The reaction conditions of the catalytic cracking reaction zone of the intermediate base wax oil and its hydrogenation and upgrading products are: reaction temperature 640°C, space velocity 4h -1 The amount of atomizing steam (accounting for the weight ratio of fresh raw materials) is 10%. The catalytic cracking reaction device is a conventional structure in the art.

[0103] Table 4

[0104]

[0105] Note: * refers to the actual yield under the same process conditions in a small fixed fluidized bed reactor.

[0106] Figure 5 The linear correlation diagram of the low carbon olefin potential yield index of the intermediate base wax oil raw material and its hydrogenation product obtained by the method of the present disclosure and the actual propylene yield and (ethylene + propylene) yield of catalytic cracking is shown in Table 4 and Figure 5 It can be seen that the relative order of the low-carbon olefin potential yield index of the intermediate-base wax oil raw material and its hydrogenation and modification products and the actual yield of low-carbon olefins is G<H<I. The method disclosed in the present invention can reflect the relative advantages and disadvantages of the potential of the wax oil raw material and its different hydrogenation and modification oils to produce propylene and low-carbon olefins, and there is a good linear correlation between the low-carbon olefin potential yield index and the actual yield, indicating that the method disclosed in the present invention can provide a directional reference for the optimization of the hydrogenation and modification conditions of hydrocarbon-based raw materials.

[0107] Example 4

[0108] For intermediate base hydroprocessing residues J-O, about 50 mg of sample was weighed, and the same steps as in Example 3 were used to analyze and calculate the relative advantages and disadvantages of the low-carbon olefin potential yield index of the six intermediate base hydroprocessing residues and their actual propylene yield and (ethylene + propylene) yield by catalytic cracking, as shown in Table 5.

[0109] The reaction conditions of the catalytic cracking reaction zone of the intermediate base hydroresidue are: reaction temperature 570°C, space velocity 4h -1 , catalyst-oil weight ratio is 12, and the amount of atomizing steam (accounting for the weight ratio of fresh raw materials) is 25% by weight. The catalytic cracking reaction device is a conventional structure in the art.

[0110] Table 5

[0111]

[0112] Note: * refers to the actual yield under the same process conditions in a small fixed fluidized bed reactor.

[0113] Figure 6 The linear correlation diagram of the low carbon olefin potential yield index of the intermediate base hydrogenated residue obtained by the method of the present disclosure and the actual propylene yield and (ethylene + propylene) yield of catalytic cracking is shown in Table 5 and Table 6. Figure 6It can be seen that the relative order of the low-carbon olefin potential yield index and the actual yield of low-carbon olefins of the six intermediate-base hydrogenated residues is basically consistent. The method disclosed in the present invention can reflect the relative advantages and disadvantages of the potential of intermediate-base residues to produce propylene and low-carbon olefins under different hydrogenation and upgrading conditions, and there is a good linear correlation between the low-carbon olefin potential yield index and the actual yield, indicating that the method disclosed in the present invention can provide a directional reference for the optimization of hydrogenation and upgrading conditions for hydrocarbon-based raw materials.

[0114] Comparative Example 1

[0115] This comparative example refers to the method in Example 1 and uses the same raw materials. The difference from Example 1 is that the values ​​of the characteristic mass-to-charge ratio are replaced with 78, 92, 106, 120, 134 and 148, and 91, 105, 119, 133, 147 and 161, a total of 12 values, and the rest of the process is the same as Example 1.

[0116] The relative advantages and disadvantages of the calculated low-carbon olefin potential yield index of the three vacuum gas oils and their actual propylene yield and (ethylene + propylene) yield by catalytic cracking are compared in Table 6 below. The linear correlation diagram of the obtained straight-run vacuum gas oil low-carbon olefin potential yield index and the actual propylene yield and (ethylene + propylene) yield by catalytic cracking is shown in Figure 7 .

[0117] Table 6

[0118]

[0119] Note: * refers to the actual yield under the same process conditions in a small fixed fluidized bed reactor.

[0120] From Table 6 and Figure 7 It can be seen that the relative order of the low-carbon olefin potential yield index calculated using the mass-to-charge ratio and its peak intensity data in the comparative example is inconsistent with the actual yield and the linear correlation becomes worse. Comparing Comparative Example 1 with Examples 1 to 3, it can be seen that the low-carbon olefin potential yield index of the hydrocarbon-based raw material calculated using the method provided by the present disclosure and the characteristic mass-to-charge ratio can reflect the relative advantages and disadvantages of the potential of different hydrocarbon-based raw materials to produce propylene and low-carbon olefins, and the linear correlation between the low-carbon olefin potential yield index and the actual yield is better.

[0121] The preferred embodiments of the present disclosure are described in detail above; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0122] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0123] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for determining the low carbon olefin potential yield index LOI of a hydrocarbon-based feedstock, characterized in that: The following steps are involved: S1, allowing the target hydrocarbon-based raw material to enter a gas chromatography-mass spectrometry analysis system for analysis and processing to obtain mass-to-charge ratio distribution data of the target hydrocarbon-based raw material; S2. Obtaining characteristic peak intensity corresponding to the characteristic mass-to-charge ratio of the target hydrocarbon-based raw material according to the mass-to-charge ratio distribution data, wherein the values ​​of the characteristic mass-to-charge ratio include 41+14n and 43+14n, and n is 0, 1, 2, 3, 4 and 5 respectively; S3. Calculate the low-carbon olefin potential yield index LOI of the target hydrocarbon-based feedstock according to the following formula (1): Where, (m / z) k represents the value of the kth characteristic mass-to-charge ratio among all characteristic mass-to-charge ratios represented by 41+14n and 43+14n in step S2, I (m / z)k represents the characteristic peak intensity corresponding to the kth characteristic mass-to-charge ratio, I (m / z)i It represents the peak intensity corresponding to the i-th mass-to-charge ratio among all the spectral peaks corresponding to the mass-to-charge ratios within the scanning range of the mass spectrometry analysis spectrum. Int is the rounding operator.

2. The method according to claim 1, characterized in that: The characteristic peak intensity corresponding to the characteristic mass-to-charge ratio includes: the maximum value of the intensity of the spectrum peak within the range of ±0.5Da of the characteristic mass-to-charge ratio.

3. The method according to claim 1, characterized in that: The target hydrocarbon-based raw materials include one or more of straight-run petroleum fractions and hydrogenation products thereof, atmospheric residue oil, vacuum residue oil and hydrogenation products thereof, Fischer-Tropsch synthetic oil and hydrogenation products thereof, deasphalted oil and hydrogenation products thereof, coal tar and hydrogenation products thereof, and waste plastic pyrolysis oil and hydrogenation products thereof.

4. The method according to claim 1, characterized in that: The method further includes: Before step S1, sampling the hydrocarbon-based feedstock or mixing the hydrocarbon-based feedstock with a solvent to obtain the target hydrocarbon-based feedstock; Optionally, when the hydrocarbon-based raw material is mixed with a solvent, the amount of the solvent used is 0.01 to 0.1 ml, preferably 0.02 to 0.05 ml, per mg of the hydrocarbon-based raw material; Optionally, the solvent is selected from one or more of n-pentane, n-hexane, n-heptane, dichloromethane and toluene.

5. The method according to claim 4, characterized in that The method further includes: The target hydrocarbon-based raw material is subjected to ultrasonic oscillation treatment and then introduced into a gas chromatography-mass spectrometry analysis system.

6. The method according to claim 5, characterized in that The conditions of the ultrasonic oscillation treatment include: ultrasonic frequency of 15 to 40 KHz, ultrasonic power of 1000 to 4000 W, and treatment time of 10 to 30 minutes.

7. The method according to claim 1, characterized in that The gas chromatograph in the gas chromatography-mass spectrometry analysis system adopts a capillary chromatographic column with an upper temperature limit in the range of 350-400° C.; the capillary chromatographic column does not contain a stationary phase membrane or contains 100% methyl polysiloxane, or the capillary chromatographic column contains a non-polar bonded stationary phase membrane.

8. The method according to claim 1, characterized in that The mass-to-charge ratio scanning mode of the mass spectrometer in the gas chromatography-mass spectrometry analysis system is full scanning, the value of the initial mass-to-charge ratio is 10-42; and an EI ionization source is used.

9. The method according to claim 1, characterized in that: The acquisition conditions of the gas chromatography-mass spectrometry analysis system include: the temperature of the injection port is 320-400°C; the injection volume is 0.1-2 μL, the initial temperature of the chromatographic column box is 30-100°C, the temperature is increased to 300-400°C at a rate of 20-40°C / min, and the final temperature section is maintained for 5-15 min, the temperature of the gas chromatography and mass spectrometry transmission line is 300-400°C, the mass spectrometry tuning mode is standard spectrum tuning, the electron bombardment energy is 10-70 eV, and the solvent delay is 0-3 min; Preferably, the temperature of the injection port is 320-350°C; the injection volume is 0.5-1 μL, the initial temperature of the chromatographic column box is 30-50°C, the temperature is increased to 320-350°C at a rate of 30-40°C / min, and maintained in the final temperature section for 7-10 min, the gas chromatography and mass spectrometry transmission line temperature is 320-340°C, the mass spectrometry electron bombardment energy is 50-70 eV, and the solvent delay is 2.5-3 min.

10. A method for selecting a hydrocarbon-based raw material that produces more low-carbon olefins, characterized in that: The following steps are involved: Determine the light olefin potential yield index LOI of multiple target hydrocarbon-based feedstocks respectively according to the method described in any one of claims 1 to 9; The obtained multiple low-carbon olefin potential yield indexes LOI are used to determine the ability of the multiple target hydrocarbon-based raw materials to produce more low-carbon olefins in order of numerical value, wherein the larger the low-carbon olefin potential yield index LOI is, the stronger the ability of the target hydrocarbon-based raw material to produce more low-carbon olefins is.

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