Optimized processing method of heavy naphtha
By iteratively adjusting the fraction cut-off point and classifying heavy naphtha fractions, the problem of underutilization of resources in traditional heavy naphtha processing has been solved, thereby reducing air and energy consumption and improving the processing efficiency of heavy naphtha.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PETROCHINA CO LTD
- Filing Date
- 2024-10-22
- Publication Date
- 2026-04-24
AI Technical Summary
Traditional heavy naphtha processing methods fail to fully utilize the maximum value of various hydrocarbon components, resulting in increased empty and energy consumption in catalytic reforming units and low efficiency.
By iteratively adjusting the fraction cut-off point, heavy naphtha fractions are classified, and fractions with a carbon number greater than or equal to a preset number are filtered out. Different processing methods are then applied to different categories of fractions, such as steam cracking and catalytic reforming.
This method increases the content of fractions with a carbon number of at least a preset amount in the catalytic reforming feedstock, reduces investment costs and process energy consumption, and yields higher-value heavy naphtha products.
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Figure CN121914765A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of petrochemical technology, and in particular to an optimized processing method for heavy naphtha. Background Technology
[0002] Traditional naphtha processing involves separating light and heavy naphtha, utilizing them as a single unit, which fails to fully exploit the maximum value of various hydrocarbon components. Traditionally refined heavy naphtha has an initial boiling point of 65°C, and its fractions contain approximately 10-20% low-carbon hydrocarbons (hydrocarbons with fewer than 7 carbon atoms). Using low-carbon hydrocarbons as feedstock for catalytic reforming leads to increased waste in the reforming unit and post-reaction separation, resulting in increased investment costs and energy consumption for catalytic reforming, and ultimately, low efficiency. Summary of the Invention
[0003] In view of the above problems, the present invention is proposed to provide an optimized processing method for naphtha that overcomes or at least partially solves the above problems.
[0004] On one hand, embodiments of the present invention provide an optimized processing method for heavy naphtha, comprising:
[0005] Within a preset temperature range between the initial boiling point and the final boiling point, the fraction cut-off point is iteratively adjusted based on pre-acquired data on the initial boiling point, final boiling point, fraction cut-off point, and molecular composition of the heavy naphtha, until the content of fractions with a carbon number greater than or equal to a preset number in the distillates from the initial boiling point and the fraction cut-off point is maximized. The fraction cut-off point corresponding to the point where the content of fractions with a carbon number greater than or equal to the preset number in the distillates from the initial boiling point and the fraction cut-off point is maximized is taken as the final fraction cut-off point of the heavy naphtha, and the fraction cut-off points of the heavy naphtha at the initial boiling point and the final boiling point are obtained respectively. The fractional data between the final fraction cut-off points, and the fractional data of the heavy naphtha between the final fraction cut-off point and the final boiling point; the fraction cut-off point is located between the initial boiling point and the final boiling point; the molecular composition data includes: carbon atom data of each fraction of the heavy naphtha; the fractional data of the heavy naphtha between the initial boiling point and the final fraction cut-off point includes: carbon atom data of each fraction of the heavy naphtha between the initial boiling point and the final fraction cut-off point; the fractional data of the heavy naphtha between the final fraction cut-off point and the final boiling point includes carbon atom data of each fraction;
[0006] The fractions of the heavy naphtha between the initial boiling point and the final fraction cut-off point are classified to obtain permeate and residue.
[0007] The permeate, the residue, and the fraction of heavy naphtha between the final fraction cut-off point and the final boiling point are processed separately.
[0008] In one embodiment, the fraction cut-off point is iteratively adjusted to obtain fractional data of the heavy naphtha between the initial boiling point and the final fraction cut-off point, and fractional data of the heavy naphtha between the final fraction cut-off point and the final boiling point, including:
[0009] A first intermediate temperature value is calculated based on the initial boiling point and the fraction cut-off point; a second intermediate temperature value is calculated based on the fraction cut-off point and the final boiling point; the first intermediate temperature value is located between the initial boiling point and the fraction cut-off point; the second intermediate temperature value is located between the fraction cut-off point and the final boiling point.
[0010] For all temperature sub-intervals, the fractional data of heavy naphtha distilled within each temperature sub-interval are calculated. The temperature sub-intervals include: a first temperature sub-interval between the initial boiling point and the median of a first temperature; a second temperature sub-interval between the initial boiling point and the median of a second temperature; a third temperature sub-interval between the initial boiling point and the fraction cut-off point; and a fourth temperature sub-interval between the fraction cut-off point and the final boiling point. The fractional data includes: first fractional data from the first temperature sub-interval, second fractional data from the second temperature sub-interval, third fractional data from the third temperature sub-interval, and fourth fractional data from the fourth temperature sub-interval. The first fractional data includes the content of each first fraction; the second fractional data includes the content of each second fraction; the third fractional data includes the content of each third fraction; and the fourth fractional data includes the content of each fourth fraction.
[0011] If the content of the desired fraction in the first fraction data is greater than the content of the desired fraction in the second fraction data and the content of the desired fraction in the third fraction data, then the fraction cut-off point is taken as the final boiling point, and the first temperature median is taken as the fraction cut-off point. If the content of the desired fraction in the second fraction data is greater than the content of the desired fraction in the first fraction data and the content of the desired fraction in the third fraction data, then the fraction cut-off point is taken as the initial boiling point, and the second temperature median is taken as the fraction cut-off point. If the content of the desired fraction in the third fraction data is greater than the content of the desired fraction in the first fraction data and the content of the desired fraction in the second fraction data, then the first temperature median is taken as the initial boiling point, the fraction cut-off point is taken as the fraction cut-off point, and the second temperature median is taken as the final boiling point. The desired fraction is a fraction with a carbon number greater than or equal to a preset number.
[0012] Repeat the above steps until the content of fractions with a carbon number greater than or equal to a preset number among the fractions distilled from the initial boiling point and the fraction cut-off point of heavy naphtha is the highest. The fraction cut-off point corresponding to the highest content of fractions with a carbon number greater than or equal to the preset number among the fractions distilled from the initial boiling point and the fraction cut-off point of heavy naphtha is taken as the final fraction cut-off point of heavy naphtha. The fraction data of heavy naphtha between the initial boiling point and the final fraction cut-off point is obtained based on the third fraction. The fraction data of heavy naphtha between the final fraction cut-off point and the final boiling point is obtained based on the fourth fraction.
[0013] In one embodiment, calculating the fractional data of heavy naphtha distilled in each temperature range includes:
[0014] Based on the pre-acquired molecular composition data of heavy naphtha, the distillation range data and yield data of the heavy naphtha fractions within the specified temperature range are calculated. The distillation range data includes the ratio of the volume of each fraction of the heavy naphtha within the specified temperature range to the volume of all types of fractions. The yield data includes the ratio of the content of each fraction of the heavy naphtha within the specified temperature range to the content of the corresponding molecular component in the molecular composition data of the heavy naphtha.
[0015] Based on the distillation range data and the yield data, the fractional data of heavy naphtha distilled within the temperature range are obtained.
[0016] In one embodiment, after the step of iteratively adjusting the fraction cut-off point and before the step of classifying the heavy naphtha fractions between the initial boiling point and the final fraction cut-off point, the method further includes:
[0017] Calculate the overlapping region of the fifth temperature sub-interval and the sixth temperature sub-interval; the fifth temperature sub-interval is the temperature range from the initial boiling point to the final fraction cut-off point; the sixth temperature sub-interval is the temperature range from the final fraction cut-off point to the final boiling point;
[0018] The fraction of heavy naphtha distilled from the overlapping interval is adjusted to the fifth or sixth temperature sub-interval.
[0019] In one embodiment, calculating the overlapping region between the fifth temperature sub-interval and the sixth temperature sub-interval includes:
[0020] The minimum and maximum temperatures of the overlapping intervals are obtained according to the following calculation formulas. The overlapping intervals are then determined based on these formulas, including:
[0021] T min =T cut ×(1-SF)
[0022] T max =T cut ×(1+SF)
[0023] Among them, T min T is the minimum temperature value within the overlapping interval. max T represents the maximum temperature within the overlapping region. cut The final fraction cut point is SF, which is the pre-obtained separation index.
[0024] In one embodiment, adjusting the fraction distilled from the heavy naphtha in the overlapping temperature range to the fifth or sixth temperature sub-range includes:
[0025] Based on the boiling point data of the pre-acquired heavy naphtha fraction data, the fraction of heavy naphtha distilled in the overlapping range is determined;
[0026] For each fraction of heavy naphtha distilled within the overlapping interval, a fifth fraction and a sixth fraction are obtained according to the following calculation formula; the fifth fraction is: a fraction of heavy naphtha distilled within the overlapping interval adjusted to the fraction of heavy naphtha distilled within the fifth temperature sub-interval; the sixth fraction is: a fraction of heavy naphtha distilled within the overlapping interval adjusted to the fraction of heavy naphtha distilled within the sixth temperature sub-interval; including:
[0027]
[0028] in, This refers to the content data of the fraction in the fifth fraction. T represents the content data of the fraction in the sixth fraction. i T is the boiling point of the fraction. min C is the minimum value of the overlapping interval. i The content data of the fraction distilled from the heavy naphtha within the overlapping interval;
[0029] For each fraction of heavy naphtha distilled in the overlapping interval, the content of the heavy naphtha in the fifth temperature sub-interval is adjusted according to the content data of the fraction in the fifth fraction, and the content of the heavy naphtha in the sixth temperature sub-interval is adjusted according to the content data of the fraction in the sixth fraction.
[0030] In one embodiment, the fraction of the heavy naphtha between the initial boiling point and the final fraction cut-off point is classified to obtain permeate and residue, including:
[0031] Based on the fraction data of heavy naphtha between the initial boiling point and the final fraction cut-off point and the preset initial membrane separation operating temperature, the permeate yield data of the heavy naphtha between the initial boiling point and the final fraction cut-off point is obtained; the permeate yield data includes: the content data of each permeate of the heavy naphtha between the initial boiling point and the final fraction cut-off point, and the ratio data of the content data of the molecular component corresponding to the permeate in the molecular component data of the heavy naphtha.
[0032] Adjust the initial membrane separation operating temperature value until the yield data of the preset type of permeate in the molecular composition data of the permeate is the highest, and take the membrane separation operating temperature corresponding to the highest yield data as the final membrane separation operating temperature;
[0033] At the final membrane separation operating temperature, the fraction of heavy naphtha between the initial boiling point and the final fraction cut-off point is subjected to membrane separation to obtain permeate and residue.
[0034] In one embodiment, the processing of the permeate, the residue, and the heavy naphtha fraction between the final fraction cut-off point and the final boiling point includes:
[0035] The permeate is subjected to steam pyrolysis.
[0036] The residues and the fractions of heavy naphtha between the final fraction cut-off point and the final boiling point are subjected to catalytic reforming.
[0037] In one embodiment, catalytic reforming of the residue and the heavy naphtha fraction between the final fraction cut-off point and the final boiling point includes:
[0038] At a preset hydrogenation temperature, the permeate and the fraction of heavy naphtha between the final fraction cut-off point and the final boiling point are hydrogenated to obtain the hydrogenated product.
[0039] At a preset reforming reaction temperature, the hydrogenated product is subjected to catalytic reforming to obtain a reformed product.
[0040] The reformed product is converted into a reformed product, and the benefit value of the reformed product is calculated based on the preset reformed product price weight data.
[0041] The hydrogenation temperature and the reforming reaction temperature are adjusted until the benefit value of the reformed product is maximized. The hydrogenation temperature corresponding to the maximum benefit value of the reformed product is taken as the final hydrogenation temperature, and the reforming reaction temperature corresponding to the maximum benefit value of the reformed product is taken as the final reforming reaction temperature.
[0042] At the final hydrogenation temperature, the residue and heavy naphtha are hydrogenated at the final fraction cut-off point and the fraction between the final fraction cut-off point to obtain the final hydrogenated product; at the final reforming reaction temperature, the residue and heavy naphtha are catalytically reformed at the final fraction cut-off point and the fraction between the final fraction cut-off point to obtain the reformed product.
[0043] In one embodiment, the catalytic reforming of the hydrogenation product at a preset reforming reaction temperature to obtain a reformed product includes:
[0044] Based on the hydrogenation products, the type of catalytic reforming reactor, and the catalyst in the catalytic reforming reactor, several different reaction rules are established;
[0045] A catalytic reforming reaction network is generated based on the reaction rules and the hydrogenation products. The catalytic reforming reaction network includes multiple nodes and multiple directed edges. Each node includes the hydrogenation products, intermediate products, and reforming products. The directed edges are used to connect two nodes, representing the reaction paths between the hydrogenation products, intermediate products, and reforming products.
[0046] Based on the pre-defined reaction conversion rate of each directed edge, the reaction depth of the hydrogenation product in the catalytic reforming reactor, and the reaction network, a prediction model for the reforming product is established; the prediction model for the reforming product includes: all components of the reforming product and the predicted content of each component;
[0047] The hydrogenation product is subjected to catalytic reforming according to the predicted model of the reforming product to obtain the reforming product.
[0048] In one embodiment, the pre-acquired molecular composition data of the heavy naphtha is obtained in the following manner:
[0049] The molecular composition chromatographic data of heavy naphtha were determined using chromatographic analysis methods.
[0050] Based on the molecular composition chromatographic data of the heavy naphtha, the mapping relationship between the molecular component data and the molecular composition chromatographic data of the heavy naphtha is determined.
[0051] The molecular component data of the heavy naphtha is obtained based on the mapping relationship between the molecular component data and the molecular composition chromatographic data.
[0052] In one embodiment, the pre-acquired molecular composition data of the heavy naphtha is obtained in the following manner:
[0053] The initial molecular content data of the heavy naphtha is obtained based on the pre-acquired initial physical property data of the heavy naphtha and the physical property data of the heavy naphtha samples in the pre-constructed molecular database; the molecular database includes: molecular content data of at least one heavy naphtha sample and its corresponding physical property data.
[0054] Based on the initial molecular content data of the heavy naphtha, the physical property data of the heavy naphtha were obtained.
[0055] Based on the deviation between the physical property data of the heavy naphtha and the initial physical property data of the heavy naphtha, the molecular content data of the heavy naphtha is adjusted to obtain the adjusted molecular content data of the heavy naphtha; based on the adjusted molecular content data of the heavy naphtha, the physical property data of the heavy naphtha are adjusted.
[0056] Repeat the steps above to adjust the molecular content data and physical property data of the heavy naphtha until the deviation between the physical property data of the heavy naphtha and the initial physical property data of the heavy naphtha is less than a preset deviation threshold.
[0057] Based on the adjusted molecular content data of the heavy naphtha, the molecular component data of the heavy naphtha are obtained.
[0058] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:
[0059] The optimized processing method for heavy naphtha provided in this invention iteratively adjusts the size of the fraction cut-off point to filter out fractions with fewer than a preset number of carbon atoms in the fractions between the initial boiling point and a preset temperature value. Subsequent processing classifies the heavy naphtha fractions and applies different processing methods to different categories of fractions. This increases the content of fractions with a preset number of carbon atoms or higher in subsequent processing, avoiding the waste of subsequent processing equipment and the need for separation operations after subsequent processing caused by fractions with fewer than the preset number of carbon atoms. This reduces investment costs and process energy consumption, resulting in a higher-value heavy naphtha product.
[0060] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.
[0061] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0062] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:
[0063] Figure 1 A flowchart illustrating the optimized processing method for heavy naphtha provided in this embodiment of the invention;
[0064] Figure 2 A flowchart illustrating the practical application of the optimized processing method for naphtha provided in this embodiment of the invention. Detailed Implementation
[0065] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
[0066] Before introducing the method provided in the embodiments of the present invention, let me briefly introduce heavy naphtha. Heavy naphtha is the fraction of crude oil or other materials at 65°C or above. Correspondingly, light naphtha is the fraction of crude oil or other materials at below 65°C.
[0067] To address the aforementioned problems, this invention provides an optimized processing method for heavy naphtha, the flowchart of which is shown below. Figure 1 As shown, it includes the following steps:
[0068] S11. Within the preset temperature range between the initial boiling point and the final boiling point, based on the pre-acquired data on the initial boiling point, final boiling point, fraction cut-off point, and molecular composition of heavy naphtha, iteratively adjust the size of the fraction cut-off point until the content of fractions with a carbon number greater than or equal to a preset number in the distillate from the initial boiling point and the fraction cut-off point is maximized. The fraction cut-off point corresponding to the point where the content of fractions with a carbon number greater than or equal to a preset number in the distillate from the initial boiling point and the fraction cut-off point is maximized is taken as the final fraction cut-off point of heavy naphtha, and the fractions of heavy naphtha at the initial boiling point and the final boiling point are obtained respectively. Fractional data between the cut-off points, and fractional data of heavy naphtha between the final cut-off point and the final boiling point; the cut-off point is located between the initial boiling point and the final boiling point; molecular composition data includes: carbon atom data for each fraction of heavy naphtha; fractional data of heavy naphtha between the initial boiling point and the final cut-off point includes: carbon atom data for each fraction of heavy naphtha between the initial boiling point and the final cut-off point; fractional data of heavy naphtha between the final cut-off point and the final boiling point includes: carbon atom data for each fraction of heavy naphtha between the final cut-off point and the final boiling point;
[0069] The preset initial boiling point can be, for example, 70°C, and the preset final boiling point can be, for example, 90°C;
[0070] S12. The fractions of heavy naphtha between the initial boiling point and the final fraction cut-off point are classified to obtain permeate and residue.
[0071] S13. Process the permeate, residue, and the fraction of heavy naphtha between the final fraction cut-off point and the final boiling point.
[0072] The fractions with a carbon number greater than or equal to a preset number in step S11 can be hydrocarbons with a carbon number of 7 or more. Correspondingly, the optimized processing method for heavy naphtha provided in this embodiment of the invention increases the content of hydrocarbons with a carbon number of 7 or more in the feed for catalytic reforming (i.e., the residue in step S13 of this method and the fraction of heavy naphtha between the final fraction cut-off point and the final boiling point), avoids the waste of the catalytic reforming unit caused by hydrocarbons with a carbon number of 6 or less, and avoids the step of separating hydrocarbons with a carbon number of 6 or less after the catalytic reforming reaction, thereby reducing investment costs and process energy consumption and obtaining more valuable aromatic products.
[0073] In the aforementioned step S11, the molecular composition data of naphtha can be represented, for example, by structure-oriented lumping (SOL). SOL is a lumping method based on the molecular scale. It achieves molecular-scale lumping through a new concept and can better reflect the molecular composition of heavy oil. Aromatic hydrocarbons are hydrocarbons with aromatic properties, generally referring to compounds containing benzene rings in their molecules.
[0074] Specifically, step S11 can be performed in the following manner, for example:
[0075] Calculate the first intermediate temperature value based on the initial boiling point and the fraction cut-off point; calculate the second intermediate temperature value based on the fraction cut-off point and the final boiling point; the first intermediate temperature value can be, for example, the average of the initial boiling point and the fraction cut-off point; the second intermediate temperature value can be, for example, the average of the fraction cut-off point and the final boiling point.
[0076] For each temperature sub-interval, the fractions distilled from heavy naphtha within each temperature sub-interval are calculated. The temperature sub-intervals may include, for example, a first temperature sub-interval between the initial boiling point and the median of a first temperature, a second temperature sub-interval between the initial boiling point and the median of a second temperature, a third temperature sub-interval between the initial boiling point and the fraction cut-off point, and a fourth temperature sub-interval between the fraction cut-off point and the final boiling point. The fraction data may include, for example, first fraction data from the first temperature sub-interval, second fraction data from the second temperature sub-interval, third fraction data from the third temperature sub-interval, and fourth fraction data from the fourth temperature sub-interval. The first fraction data includes the content data of at least one first fraction; the second fraction data includes the content data of at least one second fraction; the third fraction data includes the content data of at least one third fraction; and the fourth fraction data includes the content data of at least one fourth fraction.
[0077] If the content of the desired fraction in the first fraction data is greater than the content of the desired fraction in the second fraction data and the content of the desired fraction in the third fraction data, then the fraction cut-off point is taken as the final boiling point, and the first temperature median is taken as the fraction cut-off point. If the content of the desired fraction in the second fraction data is greater than the content of the desired fraction in the first fraction data and the content of the desired fraction in the third fraction data, then the fraction cut-off point is taken as the initial boiling point, and the second temperature median is taken as the fraction cut-off point. If the content of the desired fraction in the third fraction data is greater than the content of the desired fraction in the first fraction data and the content of the desired fraction in the second fraction data, then the first temperature median is taken as the initial boiling point, the fraction cut-off point is taken as the fraction cut-off point, and the second temperature median is taken as the final boiling point. The desired fraction is a fraction with a carbon number greater than or equal to a preset number.
[0078] Repeat the above steps until the fractions from the initial boiling point and the fraction cut-off point of heavy naphtha have the highest content of fractions with a carbon number greater than or equal to a preset number. The fraction cut-off point corresponding to the highest content of fractions with a carbon number greater than or equal to the preset number from the initial boiling point and the fraction cut-off point of heavy naphtha is taken as the final fraction cut-off point of heavy naphtha. The fraction data of heavy naphtha between the initial boiling point and the final fraction cut-off point is obtained based on the third fraction, and the fraction data of heavy naphtha between the final fraction cut-off point and the final boiling point is obtained based on the fourth fraction.
[0079] The method for iteratively finding the fraction cut-off point provided in this embodiment of the invention divides the temperature range between the initial boiling point and the final boiling point into two parts based on the fraction cut-off point. By dividing the temperature range into two parts in each iteration, it is possible to quickly and accurately find the fraction cut-off point corresponding to the point where the content of fractions with a carbon number greater than or equal to a preset number is maximized in heavy naphtha at the initial boiling point and the fraction cut-off point.
[0080] Specifically, the aforementioned calculation of the distillate data of heavy naphtha in each temperature range may include, for example, the following steps:
[0081] Based on the pre-acquired molecular composition data of heavy naphtha, calculate the distillation range data and yield data of the fractions of heavy naphtha within the temperature range. The distillation range data includes the ratio of the volume of each fraction of heavy naphtha within the temperature range to the volume of all types of fractions. The yield data includes the ratio of the content of each fraction of heavy naphtha within the temperature range to the content of the corresponding molecular component in the molecular composition data of the heavy naphtha.
[0082] Based on the distillation range data and yield data, the fraction data of heavy naphtha distilled within the temperature range were obtained.
[0083] In one embodiment, since there is some overlap between the fractions distilled from heavy naphtha in the temperature range from the initial boiling point to the final fraction cut-off point and the fractions distilled in the temperature range from the final fraction cut-off point to the final boiling point at the final fraction cut-off point, after the step of iteratively adjusting the fraction cut-off point and before the step of classifying the fractions of heavy naphtha between the initial boiling point and the final fraction cut-off point, the aforementioned optimized processing method for heavy naphtha further includes the following steps:
[0084] Calculate the overlap between the fifth and sixth temperature sub-intervals; the fifth temperature sub-interval is the temperature range from the initial boiling point to the final fraction cut-off point; the sixth temperature sub-interval is the temperature range from the final fraction cut-off point to the final boiling point; for example, this includes the following steps:
[0085] The minimum and maximum temperatures of the overlapping intervals are obtained using the following formulas. Based on these values, the overlapping intervals are then determined, including:
[0086] T min =T cut ×(1-SF)
[0087] T max =T cut ×(1+SF)
[0088] Among them, T min T represents the minimum temperature within the overlapping region. max T represents the maximum temperature within the overlapping region. cut The final fraction cut-off point is SF, which is the pre-obtained separation index.
[0089] Adjusting the fraction of heavy naphtha distilled in the overlapping temperature range to the fifth or sixth temperature sub-range; for example, this includes the following steps:
[0090] Based on the boiling point data of the pre-acquired heavy naphtha fraction data, the fractions distilled from the heavy naphtha in the overlapping range are determined.
[0091] For each fraction of heavy naphtha distilled within the overlapping interval, the fifth and sixth fractions are obtained according to the following calculation formulas; the fifth fraction is: the fraction of heavy naphtha distilled within the overlapping interval adjusted to the fraction of heavy naphtha distilled within the fifth temperature sub-interval; the sixth fraction is: the fraction of heavy naphtha distilled within the overlapping interval adjusted to the fraction of heavy naphtha distilled within the sixth temperature sub-interval; including:
[0092]
[0093] in, This refers to the content data of this fraction in the fifth distillation fraction. The content data of this fraction in the sixth fraction, T i T is the boiling point of the fraction. min C is the minimum value of the overlapping interval. i This represents the content data of the fraction distilled from heavy naphtha within the overlapping region;
[0094] For each fraction of heavy naphtha distilled in the overlapping interval, the content of that fraction in the fifth temperature sub-interval of heavy naphtha is adjusted based on the content data of that fraction in the fifth fraction, and the content of that fraction in the sixth temperature sub-interval of heavy naphtha is adjusted based on the content data of that fraction in the sixth fraction.
[0095] In step S12 above, the fractional data of heavy naphtha between the initial boiling point and the final fraction cut-off point are classified, for example, in the following manner:
[0096] Based on the fraction data of heavy naphtha between the initial boiling point and the final fraction cut-off point and the preset initial membrane separation operating temperature, the permeate yield data of the fraction of heavy naphtha between the initial boiling point and the final fraction cut-off point is obtained; the permeate yield data includes: the content data of each permeate of heavy naphtha between the initial boiling point and the final fraction cut-off point, and the ratio data of the content data of the molecular component corresponding to the permeate in the molecular component data of heavy naphtha;
[0097] Adjust the initial membrane separation operating temperature until the yield data of the preset type of permeate in the molecular composition data of the permeate is the highest. The membrane separation operating temperature corresponding to the highest yield data is taken as the final membrane separation operating temperature. The preset type of permeate may include, for example, n-hexane and methylpentane.
[0098] At the final membrane separation operating temperature, the fraction of heavy naphtha between the initial boiling point and the final fraction cut-off point is subjected to membrane separation to obtain permeate and residue; for example, a mesoporous molecular sieve membrane with a pore size of 0.5-0.6 nm can be used as the membrane separation material.
[0099] The residue obtained from the aforementioned membrane separation step can, for example, be used as a gasoline blending product.
[0100] In the optimized processing method of heavy naphtha in this embodiment of the invention, membrane separation technology has the characteristics of high efficiency, simple process, low energy consumption and no pollution, and has great application potential.
[0101] The aforementioned step S13 can be performed in the following manner:
[0102] The permeate was subjected to steam pyrolysis.
[0103] Catalytic reforming is performed on the residues and the fractions of heavy naphtha between the final fraction cut-off point and the final boiling point; specifically, it may include the following steps:
[0104] At a preset hydrogenation temperature, the fractions of permeate and heavy naphtha between the final fraction cut-off point and the final boiling point are hydrogenated to obtain hydrogenated products.
[0105] At a preset reforming reaction temperature, the hydrogenation product is catalytically reformed to obtain the reformed product.
[0106] The reformed product is converted into a reformed product, and the benefit value of the reformed product is calculated based on the preset reformed product price weight data.
[0107] Adjust the hydrogenation temperature and the reforming reaction temperature until the benefit value of the reformed product is maximized. Take the hydrogenation temperature corresponding to the maximum benefit value of the reformed product as the final hydrogenation temperature, and take the reforming reaction temperature corresponding to the maximum benefit value of the reformed product as the final reforming reaction temperature.
[0108] At the final hydrogenation temperature, the fractions of the residue and heavy naphtha between the final fraction cut-off point and the final boiling point are hydrogenated to obtain the final hydrogenated product; at the final reforming reaction temperature, the fractions of the residue and heavy naphtha between the final fraction cut-off point and the final boiling point are catalytically reformed to obtain the reformed product.
[0109] The aforementioned catalytic reforming of the hydrogenation product at a predetermined reforming reaction temperature may, for example, include the following steps:
[0110] Based on the hydrogenation products, the type of catalytic reforming reactor, and the catalyst in the catalytic reforming reactor, several different reaction rules are established;
[0111] Based on the reaction rules and hydrogenation products, a catalytic reforming reaction network is generated. The catalytic reforming reaction network includes multiple nodes and multiple directed edges. The nodes include hydrogenation products, intermediate products, and reforming products. The directed edges are used to connect two nodes, representing the reaction paths between hydrogenation products, intermediate products, and reforming products.
[0112] Based on the pre-defined reaction conversion rate of each directed edge, the reaction depth of the hydrogenation product in the catalytic reforming reactor, and the reaction network, a prediction model for the reforming product is established. The prediction model for the reforming product includes: all components of the reforming product and the predicted content of each component.
[0113] Catalytic reforming of the hydrogenation product was performed according to the predicted model of the reforming product to obtain the reforming product.
[0114] In one embodiment, if a chromatographic analysis instrument is available at the time of implementation, the pre-acquired molecular component data of the heavy naphtha can be obtained in the following manner:
[0115] The molecular composition chromatographic data of heavy naphtha were determined using chromatographic analysis methods.
[0116] Based on the molecular composition chromatographic data of heavy naphtha, the mapping relationship between the molecular component data and the molecular composition chromatographic data of heavy naphtha was determined.
[0117] Based on the mapping relationship between the molecular component data and the molecular composition chromatographic data of heavy naphtha, the molecular component data of heavy naphtha were obtained.
[0118] In one embodiment, if a chromatographic analysis instrument is not available at the time of implementation, the molecular component data of the heavy naphtha obtained in advance can be obtained through the following macroscopic property inversion method:
[0119] Based on the initial physical property data of heavy naphtha and the physical property data of heavy naphtha samples in a pre-constructed molecular database, the initial molecular content data of heavy naphtha is obtained; the molecular database includes: molecular content data of at least one heavy naphtha sample and its corresponding physical property data.
[0120] Based on the initial molecular content data of heavy naphtha, the physical property data of heavy naphtha were obtained.
[0121] Based on the deviation between the physical property data of the heavy naphtha and the initial physical property data of the heavy naphtha, the molecular content data of the heavy naphtha is adjusted to obtain the adjusted molecular content data of the heavy naphtha; based on the adjusted molecular content data of the heavy naphtha, the physical property data of the heavy naphtha are adjusted.
[0122] Repeat the steps above to adjust the molecular content and physical property data of heavy naphtha until the deviation between the physical property data of heavy naphtha and the initial physical property data of heavy naphtha is less than the preset deviation threshold.
[0123] Based on the adjusted molecular content data of heavy naphtha, the molecular composition data of heavy naphtha were obtained.
[0124] The two methods for obtaining molecular component data of heavy naphtha described above can be carried out under their respective conditions, or they can be carried out simultaneously for mutual verification. Alternatively, any existing method can be used to obtain molecular component data of heavy naphtha. This embodiment of the invention does not limit this.
[0125] In one embodiment, see Figure 2 Taking an initial boiling point of 65°C and a fraction cut-off point of 80°C as an example, the optimized processing method of heavy naphtha in this embodiment of the invention is further explained:
[0126] The fractions of heavy naphtha between the initial boiling point and the fraction cut-off point can be, for example, n-hexane, cyclohexane, and dimethylpentane, as well as small amounts of methylpentane, benzene, and trimethylbutane; the fractions of heavy naphtha above the fraction cut-off point can be, for example, hydrocarbons with 7 or more carbon atoms, which can be hydrogenated according to any conventional process and then subjected to catalytic reforming.
[0127] For the fractions of heavy naphtha between the initial boiling point and the fraction cut-off point, pretreatment operations such as filtration, heating, and pressurization can be performed before feeding them into a membrane separation unit. Because hexane and methylpentane have relatively small molecular dynamic diameters, they will first pass through the membrane material into the permeate (permeate), which can be directly used for steam cracking. The residue (permeate) that does not pass through the membrane material includes, for example, cyclohexane, dimethylpentane, and benzene, and can be flexibly allocated and used according to market demand. It can be used as a high-octane gasoline blending component or for catalytic reforming to increase aromatics production. The boiling points and molecular dynamic diameters of the fractions of heavy naphtha between the initial boiling point and the fraction cut-off point are shown in Table 1 below.
[0128] When the hexane content is not less than 50%, the membrane's separation coefficient for hexane / cyclohexane (or dimethylpentane) is greater than 20, and the permeate flow rate is higher than 0.5 kg / (m³). 2 •h). The packing density of the membrane module is not less than 200m³. 2 / m 3 Efficiency is no less than 80%.
[0129] Table 1
[0130]
[0131] The heavy naphtha optimization processing method of this invention optimizes the processing of high-boiling-point fraction C. 7+The hydrocarbons are directly used for catalytic reforming, while the fraction of heavy naphtha between the initial boiling point and the fraction cut-off point is separated by membrane separation to incorporate n-hexane and methylpentane into the steam cracking feedstock. Before entering the catalytic reforming unit, straight-chain hexane is removed from the feedstock, and the remaining components such as cyclohexane, dimethylpentane, and benzene can be flexibly allocated and used according to market demand. This achieves dual-objective optimization of ethylene feedstock and reforming feedstock, which is conducive to the optimized utilization of heavy naphtha and increases the efficiency of catalytic reforming.
[0132] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. An optimized processing method for heavy naphtha, characterized in that, include: Within the preset temperature range between the initial boiling point and the final boiling point, the size of the fractional boiling point is iteratively adjusted based on the pre-acquired data of the initial boiling point, final boiling point, fractional cutting point, and molecular composition of heavy naphtha, until the content of fractions with a carbon number greater than or equal to the preset number in the fractions distilled from the initial boiling point and the fractional cutting point of heavy naphtha is the highest. The fraction cut point corresponding to the highest content of fractions with a carbon number greater than or equal to a preset number distilled from heavy naphtha within the initial boiling point and the fraction cut point is taken as the final fraction cut point of heavy naphtha. The fraction data of heavy naphtha between the initial boiling point and the final fraction cut point, and the fraction data of heavy naphtha between the final fraction cut point and the final boiling point are obtained respectively. The fraction cut-off point is located between the initial boiling point and the final boiling point; The molecular composition data includes: carbon atom data for each fraction of the heavy naphtha; the fractional data of the heavy naphtha between the initial boiling point and the final fractional cut-off point includes: carbon atom data for each fraction of the heavy naphtha between the initial boiling point and the final fractional cut-off point; the fractional data of the heavy naphtha between the final fractional cut-off point and the final boiling point includes: carbon atom data for each fraction of the heavy naphtha between the final fractional cut-off point and the final boiling point. The fractions of the heavy naphtha between the initial boiling point and the final fraction cut-off point are classified to obtain permeate and residue. The permeate, the residue, and the fraction of heavy naphtha between the final fraction cut-off point and the final boiling point are processed separately.
2. The method as described in claim 1, characterized in that, The fraction cut-off point is iteratively adjusted to obtain the fractional data of the heavy naphtha between the initial boiling point and the final fraction cut-off point, and the fractional data of the heavy naphtha between the final fraction cut-off point and the final boiling point, including: A first intermediate temperature value is calculated based on the initial boiling point and the fraction cut-off point; a second intermediate temperature value is calculated based on the fraction cut-off point and the final boiling point; the first intermediate temperature value is located between the initial boiling point and the fraction cut-off point; the second intermediate temperature value is located between the fraction cut-off point and the final boiling point. For each temperature sub-interval, the fractional data of heavy naphtha distilled within each temperature sub-interval are calculated. The temperature sub-intervals include: a first temperature sub-interval between the initial boiling point and the median of a first temperature; a second temperature sub-interval between the initial boiling point and the median of a second temperature; a third temperature sub-interval between the initial boiling point and the fraction cut-off point; and a fourth temperature sub-interval between the fraction cut-off point and the final boiling point. The fractional data includes: first fractional data from the first temperature sub-interval, second fractional data from the second temperature sub-interval, third fractional data from the third temperature sub-interval, and fourth fractional data from the fourth temperature sub-interval. The first fractional data includes the content data of at least one first fraction; the second fractional data includes the content data of at least one second fraction; the third fractional data includes the content data of at least one third fraction; and the fourth fractional data includes the content data of at least one fourth fraction. If the content of the desired fraction in the first fraction is greater than the content of the desired fraction in the second fraction and the content of the desired fraction in the third fraction, then the fraction cut-off point is taken as the final boiling point, and the first intermediate temperature value is taken as the fraction cut-off point; if the content of the desired fraction in the second fraction is greater than the content of the desired fraction in the first fraction and the content of the desired fraction in the third fraction, then the fraction cut-off point is taken as the initial boiling point, and the second intermediate temperature value is taken as the fraction cut-off point; if the content of the desired fraction in the third fraction is greater than the content of the desired fraction in the first fraction and the content of the desired fraction in the second fraction, then the first intermediate temperature value is taken as the initial boiling point, the fraction cut-off point is taken as the fraction cut-off point, and the second intermediate temperature value is taken as the final boiling point; the desired fraction is a fraction with a carbon number greater than or equal to a preset number. Repeat the above steps until the content of fractions with a carbon number greater than or equal to a preset number among the fractions distilled from the initial boiling point and the fraction cut-off point of heavy naphtha is the highest. The fraction cut-off point corresponding to the highest content of fractions with a carbon number greater than or equal to the preset number among the fractions distilled from the initial boiling point and the fraction cut-off point of heavy naphtha is taken as the final fraction cut-off point of heavy naphtha. The fraction data of heavy naphtha between the initial boiling point and the final fraction cut-off point is obtained based on the third fraction. The fraction data of heavy naphtha between the final fraction cut-off point and the final boiling point is obtained based on the fourth fraction.
3. The method as described in claim 2, characterized in that, The calculation of the distillate data of heavy naphtha in each temperature range includes: Based on the pre-acquired molecular composition data of heavy naphtha, the distillation range data and yield data of the heavy naphtha fractions within the specified temperature range are calculated. The distillation range data includes the ratio of the volume of each fraction of the heavy naphtha within the specified temperature range to the volume of all types of fractions. The yield data includes the ratio of the content of each fraction of the heavy naphtha within the specified temperature range to the content of the corresponding molecular component in the molecular composition data of the heavy naphtha. Based on the distillation range data and the yield data, the fractional data of heavy naphtha distilled within the temperature range are obtained.
4. The method as described in claim 1, characterized in that, After the step of iteratively adjusting the fraction cut-off point, and before the step of classifying the heavy naphtha fractions between the initial boiling point and the final fraction cut-off point, the method further includes: Calculate the overlap between the fifth and sixth temperature sub-intervals; the fifth temperature sub-interval is the temperature range from the initial boiling point to the final fraction cut-off point; the sixth temperature sub-interval is the temperature range from the final fraction cut-off point to the final boiling point. The fraction of heavy naphtha distilled from the overlapping interval is adjusted to the fifth or sixth temperature sub-interval.
5. The method as described in claim 4, characterized in that, The calculation of the overlapping interval between the fifth and sixth temperature sub-intervals includes: The minimum and maximum temperatures of the overlapping intervals are obtained according to the following calculation formulas. The overlapping intervals are then determined based on these formulas, including: T min =T cut ×(1-SF) T max =T cut ×(1+SF) Among them, T min T is the minimum temperature value within the overlapping interval. max T represents the maximum temperature within the overlapping region. cut The final fraction cut point is SF, which is the pre-obtained separation index.
6. The method as described in claim 5, characterized in that, The step of adjusting the distillate data of heavy naphtha distilled in the overlapping interval to the fifth or sixth temperature sub-interval includes: Based on the boiling point data of the pre-acquired heavy naphtha fraction data, the fraction of heavy naphtha distilled in the overlapping range is determined; For each fraction of heavy naphtha distilled within the overlapping interval, a fifth fraction and a sixth fraction are obtained according to the following calculation formula; the fifth fraction is: a fraction of heavy naphtha distilled within the overlapping interval adjusted to the fraction of heavy naphtha distilled within the fifth temperature sub-interval; the sixth fraction is: a fraction of heavy naphtha distilled within the overlapping interval adjusted to the fraction of heavy naphtha distilled within the sixth temperature sub-interval; including: in, This refers to the content data of the fraction in the fifth fraction. T represents the content data of the fraction in the sixth fraction. i T is the boiling point of the fraction. min C is the minimum value of the overlapping interval. i The content data of the fraction distilled from the heavy naphtha within the overlapping interval; For each fraction of heavy naphtha distilled in the overlapping interval, the content of the heavy naphtha in the fifth temperature sub-interval is adjusted according to the content data of the fraction in the fifth fraction, and the content of the heavy naphtha in the sixth temperature sub-interval is adjusted according to the content data of the fraction in the sixth fraction.
7. The method as described in claim 1, characterized in that, The heavy naphtha fraction between the initial boiling point and the final fraction cut-off point is classified to obtain permeate and residue, including: Based on the fraction data of heavy naphtha between the initial boiling point and the final fraction cut-off point and the preset initial membrane separation operating temperature, the permeate yield data of the heavy naphtha between the initial boiling point and the final fraction cut-off point is obtained; the permeate yield data includes: the content data of each permeate of the heavy naphtha between the initial boiling point and the final fraction cut-off point, and the ratio data of the content data of the molecular component corresponding to the permeate in the molecular component data of the heavy naphtha. Adjust the initial membrane separation operating temperature value until the yield data of the preset type of permeate in the molecular composition data of the permeate is the highest, and take the membrane separation operating temperature corresponding to the highest yield data as the final membrane separation operating temperature; At the final membrane separation operating temperature, the fraction of heavy naphtha between the initial boiling point and the final fraction cut-off point is subjected to membrane separation to obtain permeate and residue.
8. The method as described in claim 1, characterized in that, The processing of the permeate, the residue, and the heavy naphtha fraction between the final fraction cut-off point and the final boiling point includes: The permeate is subjected to steam pyrolysis. The residues and the fractions of heavy naphtha between the final fraction cut-off point and the final boiling point are subjected to catalytic reforming.
9. The method as described in claim 8, characterized in that, The residue and the fraction of heavy naphtha between the final fraction cut-off point and the final boiling point are subjected to catalytic reforming, including: At a preset hydrogenation temperature, the permeate and the fraction of heavy naphtha between the final fraction cut-off point and the final boiling point are hydrogenated to obtain the hydrogenated product. At a preset reforming reaction temperature, the hydrogenated product is subjected to catalytic reforming to obtain a reformed product. The reformed product is converted into a reformed product, and the benefit value of the reformed product is calculated based on the preset reformed product price weight data. The hydrogenation temperature and the reforming reaction temperature are adjusted until the benefit value of the reformed product is maximized. The hydrogenation temperature corresponding to the maximum benefit value of the reformed product is taken as the final hydrogenation temperature, and the reforming reaction temperature corresponding to the maximum benefit value of the reformed product is taken as the final reforming reaction temperature. At the final hydrogenation temperature, the residue and heavy naphtha fraction between the final fraction cut-off point and the final boiling point are hydrogenated to obtain the final hydrogenated product; at the final reforming reaction temperature, the residue and heavy naphtha fraction between the final fraction cut-off point and the final boiling point are catalytically reformed to obtain the reformed product.
10. The method as described in claim 9, characterized in that, The hydrogenation product is catalytically reformed at a preset reforming reaction temperature to obtain a reformed product, comprising: Based on the hydrogenation products, the type of catalytic reforming reactor, and the catalyst in the catalytic reforming reactor, several different reaction rules are established; A catalytic reforming reaction network is generated based on the reaction rules and the hydrogenation products. The catalytic reforming reaction network includes multiple nodes and multiple directed edges. The nodes include the hydrogenation products, intermediate products, and reforming products. The directed edges are used to connect two nodes, representing the reaction paths between the hydrogenation products, intermediate products, and reforming products. Based on the pre-defined reaction conversion rate of each directed edge, the reaction depth of the hydrogenation product in the catalytic reforming reactor, and the reaction network, a prediction model for the reforming product is established; the prediction model for the reforming product includes: all components of the reforming product and the predicted content of each component; The hydrogenation product is subjected to catalytic reforming according to the predicted model of the reforming product to obtain the reforming product.
11. The method as described in claim 1, characterized in that, The pre-acquired molecular component data of the heavy naphtha was obtained through the following method: The molecular composition chromatographic data of heavy naphtha were determined using chromatographic analysis methods. Based on the molecular composition chromatographic data of the heavy naphtha, the mapping relationship between the molecular component data and the molecular composition chromatographic data of the heavy naphtha is determined. The molecular component data of the heavy naphtha is obtained based on the mapping relationship between the molecular component data and the molecular composition chromatographic data.
12. The method as described in claim 1, characterized in that, The pre-acquired molecular component data of the heavy naphtha was obtained through the following method: The initial molecular content data of the heavy naphtha is obtained based on the pre-acquired initial physical property data of the heavy naphtha and the physical property data of the heavy naphtha samples in the pre-constructed molecular database; the molecular database includes: molecular content data of at least one heavy naphtha sample and its corresponding physical property data. Based on the initial molecular content data of the heavy naphtha, the physical property data of the heavy naphtha were obtained. Based on the deviation between the physical property data of the heavy naphtha and the initial physical property data of the heavy naphtha, the molecular content data of the heavy naphtha is adjusted to obtain the adjusted molecular content data of the heavy naphtha; based on the adjusted molecular content data of the heavy naphtha, the physical property data of the heavy naphtha are adjusted. Repeat the steps above to adjust the molecular content data and physical property data of the heavy naphtha until the deviation between the physical property data of the heavy naphtha and the initial physical property data of the heavy naphtha is less than a preset deviation threshold. Based on the adjusted molecular content data of the heavy naphtha, the molecular component data of the heavy naphtha are obtained.