Foam prevention and control method and device for fixed bed residual oil hydrogenation reaction system
By obtaining the content of the four components of the reaction-generated oil in the fixed-bed residue hydrotreating system, calculating the stability coefficient, and adjusting the temperature or feedstock properties according to the rules, the foaming problem of the hot high-pressure separator was solved, ensuring the stable operation of the unit and the continuity of downstream units.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2024-12-09
- Publication Date
- 2026-06-09
AI Technical Summary
In the initial stage of operation and during the operation cycle of a fixed-bed residue hydrotreating unit, foaming is prone to occur in the hot high-pressure separator, which causes heavy oil foam to be carried into the cold high-pressure separator by the high-separation gas, affecting the normal operation of the unit and the stability of downstream units.
The four-component content of the reaction-generated oil is obtained by measuring the content of the four components in the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator, the stability coefficient is calculated, and foaming control measures are determined according to preset rules, such as adjusting the temperature of the hot high-pressure separator, the reaction temperature, or the properties of the raw materials, to prevent foaming.
This effectively avoids the foaming phenomenon in the hot high-pressure separator, ensuring the normal operation of the unit and the stability of downstream units, and avoiding the adverse effects on catalyst life caused by rapid temperature adjustment.
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Figure CN122168333A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of residue hydrotreating technology, and in particular to a foaming control method and apparatus for a fixed-bed residue hydrotreating reaction system. Background Technology
[0002] Fixed-bed residue hydrotreating units are currently the most commonly used equipment in industry for processing low-quality residue oil. They are characterized by strong adaptability to feedstocks and simple production operation processes, and can provide high-quality feedstocks for downstream catalytic cracking processes.
[0003] In the initial stage of operation of a fixed-bed residue hydrotreating unit, and even throughout the entire operation cycle, foaming often occurs in the hot high-pressure separator. This means that the drastic fluctuations in the liquid level of the hot high-pressure separator cause foaming. This results in the high-separation gas from the hot high-pressure separator carrying heavy oil foam, which continuously and unstablely enters the cold high-pressure separator. Consequently, the oil volume in the hot low-pressure separator is significantly reduced, and the oil-water separation in the cold high-pressure separator becomes unclear. The aqueous phase will carry the oil into subsequent units, affecting stable operation.
[0004] In the existing technology, the approach taken is to sample and analyze the foaming phenomenon in the hot high-pressure separator, and then adjust the operation based on the analysis results.
[0005] The inventors discovered through research that existing technologies for dealing with the foaming phenomenon in hot high-pressure separators have at least the following drawbacks:
[0006] It is impossible to ensure the normal operation of the equipment and the stability of downstream equipment.
[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention
[0008] The purpose of this invention is to ensure the normal operation of the device and the stability of downstream devices.
[0009] This invention provides a foaming control method for a fixed-bed residue hydrotreating reaction system, wherein the fixed-bed residue hydrotreating reaction system includes a hydrotreating pretreatment reaction zone, a hydrotreating reaction zone, and a fractionation zone; the hydrotreating pretreatment reaction zone includes multiple hydrotreating reactors; the hydrotreating reaction zone includes multiple hydrotreating reactors; the fractionation zone includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator, and a cold low-pressure separator; the method includes the following steps:
[0010] S11. Obtain the content of the four components of the oil produced in the reaction in the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator; the content of the four components includes the content of aromatics, gums, saturates and asphaltenes.
[0011] S12. The stability coefficient of the reaction-generated oil is calculated based on the content of the four components in the reaction-generated oil.
[0012] S13. Using the stability coefficient as a parameter, determine the corresponding foaming control measures according to preset rules; the foaming control measures include no adjustment required, increasing the temperature of the hot high-pressure separator, increasing the reaction temperature, and adjusting the raw materials.
[0013] In another aspect of the invention, a foam control device for a fixed-bed residue hydrotreating reaction system is provided. The fixed-bed residue hydrotreating reaction system includes a hydrotreating pretreatment reaction zone, a hydrotreating reaction zone, and a fractionation zone. The hydrotreating pretreatment reaction zone includes multiple hydrotreating reactors. The hydrotreating reaction zone includes multiple hydrotreating reactors. The fractionation zone includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator, and a cold low-pressure separator. The foam control device comprises:
[0014] A sampler for extracting sample oil from the reaction-generated oil is located on the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator.
[0015] The chromatographic analyzer is used to obtain the content of four components in the reaction-generated oil; the content of the four components includes aromatic content, gum content, saturated content and asphaltenes content;
[0016] The data processing module is used to calculate the stability coefficient of the reaction-generated oil based on the content of the four components, and to determine the corresponding foaming control measures according to preset rules using the stability coefficient as a parameter; the foaming control measures include no adjustment required, increasing the temperature of the hot high-pressure separator, increasing the reaction temperature, and adjusting the raw materials.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] The inventors discovered through research that the foaming that occurs in the hot high-pressure separator is usually caused by the presence of a large amount of gum or intermediate incomplete reaction products of gum and asphaltenes in the reaction-generated oil. These substances have high interfacial activity and are prone to oil-water emulsification, which increases the difficulty of oil-water separation.
[0019] Next, through further experimental research, the inventors discovered that the magnitude of the stability coefficient of the reaction-generated oil can characterize the probability and cause of foaming in the hot high-pressure separator.
[0020] Based on the above research findings, this invention samples the reaction-generated oil in the connection pipeline between the last hydrotreating reactor and the hot high-pressure separator, and obtains the content of the four components of the sampled oil; then, the stability coefficient of the reaction-generated oil is calculated; thus, based on preset rules, the stability coefficient can be used to predict whether high-level foaming will occur and its cause, thereby determining the corresponding foaming control measures. This allows for preventive operations to be performed before foaming occurs in the hot high-pressure separator; since this invention can effectively avoid the occurrence of high-level foaming, it can ensure the normal operation of the device and the stability of downstream devices.
[0021] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other objects, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. Attached Figure Description
[0022] Figure 1 This is a flowchart illustrating the foaming control method for a fixed-bed residue hydrotreating system described in this invention.
[0023] Figure 2 This is a schematic diagram of the foaming control device for a fixed-bed residue oil hydrogenation reaction system described in this invention. Detailed Implementation
[0024] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0025] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.
[0026] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, in addition to those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” that element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.
[0027] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.
[0028] Example 1
[0029] To ensure the normal operation of the equipment and the stability of downstream equipment, refer to Figure 1 and Figure 2 This invention provides a method for controlling foaming in a fixed-bed residue hydrotreating system, comprising the following steps:
[0030] S11. Obtain the content of the four components of the oil produced in the reaction in the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator; the content of the four components includes the content of aromatics, gums, saturates and asphaltenes.
[0031] It should be noted that typical application scenarios of the embodiments of the present invention can be referred to Figure 2 The fixed-bed residue hydrotreating system includes a hydrotreating pretreatment reaction zone 01, a hydrotreating reaction zone 02, and a fractionation zone 03. The hydrotreating pretreatment reaction zone 01 includes multiple hydrotreating reactors; the hydrotreating reaction zone 02 includes multiple hydrotreating reactors; and the fractionation zone 03 includes a hot high-pressure separator 31, a cold high-pressure separator 32, a hot low-pressure separator 33, and a cold low-pressure separator 34. In practical applications, the multiple hydrotreating reactors may specifically include 2 or 3 hydrotreating reactors connected in series. The multiple hydrotreating reactors may specifically include 2 to 5 hydrotreating reactors connected in series.
[0032] To obtain the content of the four components of the reaction-generated oil, in this embodiment of the invention, a side line can be added to the pipeline between the last reactor 21 and the hot high-pressure separator 31, and a detection device for online detection of the content of the four components of the reaction-generated oil can be set up. The detection device may include a sample sampler 04 for extracting sample oil of the reaction-generated oil and a chromatographic analyzer; preferably, the chromatographic analyzer may be a rod thin-layer chromatograph or a gel permeation chromatograph.
[0033] In this embodiment of the invention, the step of obtaining the content of the four components of the reaction-generated oil in the connecting pipeline between the last hydrotreating reactor 21 and the hot high-pressure separator 31 may specifically include:
[0034] The sample oil is extracted using a sample sampler, and the amount of sample taken can be 10 μg to 0.1 g, preferably 10 μg to 100 μg;
[0035] Spot the sample oil at the top of the rod-shaped thin-layer chromatograph at 1-3 cm (preferably 2 cm), evaporate the solvent at room temperature to remove it, and then place it in a developing tank containing n-heptane for development.
[0036] After the n-heptane carrying the saturated hydrocarbons moves to a position of 10-13 cm (preferably 11-12 cm), remove the rod and dry it for 10 minutes, then place it in a developing tank containing toluene.
[0037] After the toluene carrying the aromatic components moves to 8 cm or 9 cm (preferably 8 cm), remove the rod rack and dry it for 10 minutes before placing it in the developing tank containing dichloromethane.
[0038] After the dichloromethane-methanol solvent carries the colloid to a depth of 4-5 cm (preferably 4 cm), remove the rod and dry it for 10 minutes.
[0039] After the chromatographic rod has been inserted into the inlet of the chromatographic analyzer, scanning can begin. Peak area calculation can be completed automatically by computer equipment to calculate the percentage content of each component.
[0040] S12. The stability coefficient of the reaction-generated oil is calculated based on the content of the four components in the reaction-generated oil.
[0041] In one implementation of this invention, the stability coefficient can be calculated by measuring the percentage content of the four components in the reaction-generated oil, and the formula used can be as follows:
[0042] Stability coefficient = (aromatic content wt / %) + resin content wt / %) / (saturated content wt / %) + asphaltene content wt / %), formula (1).
[0043] In another implementation of this invention, multiple stability coefficient calculation formulas can be used to calculate the stability coefficient under different conditions. These formulas are as follows:
[0044]
[0045] Among them, T CAT This represents the average temperature of the reactor bed; the correction factor K0 is set to 1.51.
[0046] The correction factor K1 is set to 1.63;
[0047] The value of the correction factor K2 is:
[0048] K2 = 1.51 + ΔT CAT / 4; where △T CAT The average temperature T of the reactor bed CAT The extent of the increase;
[0049] in, and denoted as stability coefficients obtained using formulas (2) to (4), respectively.
[0050] S13. Using the stability coefficient as a parameter, determine the corresponding foaming control measures according to preset rules; the foaming control measures include no adjustment required, increasing the temperature of the hot high-pressure separator, increasing the reaction temperature, and adjusting the raw materials.
[0051] In the existing technology, the general approach to dealing with foaming in the hot high-pressure separator 31 is as follows: when foaming occurs in the hot high-pressure separator 31 or when downstream separation devices such as the cold high-pressure separator produce problems such as unclear oil-water separation, sampling and analysis are performed; then, operational adjustments are made based on the test results. Since the foaming phenomenon has already occurred for some time, it not only affects the safe and stable operation of downstream devices, but also limits the adjustment methods that can be used in this situation. The common approach is to quickly increase the catalyst bed temperature until the foaming phenomenon disappears. However, rapidly increasing the bed temperature in a short period of time will seriously affect the catalyst life and have an irreversible impact on the operating cycle.
[0052] The inventors discovered through research that the foaming that occurs in the hot high-pressure separator is usually caused by the presence of a large amount of gum or intermediate incomplete reaction products of gum and asphaltenes in the reaction-generated oil. These substances have high interfacial activity and are prone to oil-water emulsification, which increases the difficulty of oil-water separation.
[0053] Through further experimental research, the inventors discovered that the stability coefficient of the reaction-generated oil can effectively characterize the probability and cause of foaming in the hot high-pressure separator. Specifically,
[0054] The main reasons for the presence of a large amount of gum or incomplete intermediate reaction products and asphaltenes in the reaction-generated oil are the influence of the properties of the raw materials, the catalyst, the reaction temperature, and the separation capacity of the hot high-pressure separator.
[0055] The properties of raw materials have a significant impact on foaming in hot high-pressure separators, and this phenomenon can be effectively mitigated by adjusting the type of processing oil.
[0056] In the residual oil colloidal system, alkanes and aromatics constitute the continuous phase, while gums and asphaltenes constitute the dispersed phase. Asphaltenes form the core, which is then surrounded by gums, aromatics, and saturated components.
[0057] When the aromatic content of the system is low, asphaltenes are prone to precipitation, causing instability in the entire system and leading to catalyst deactivation; insufficient reaction depth of gums and asphaltenes results in the formation of unstable reaction intermediates.
[0058] Furthermore, when the aromatic content is low or the asphaltenes content is high, the intermediate products of the reaction are not easily dissolved. Due to their hydrophilicity, the water vapor that should have been carried out with the gas phase enters the oil phase of the hot high-pressure separator, causing the liquid surface of the hot high-pressure separator to fluctuate at high temperatures and produce foaming.
[0059] The inventors discovered through research that different influencing factors have varying degrees of impact on the foaming process in hot high-pressure separators, specifically including:
[0060] 1. Increasing the temperature of the hot high-pressure separator can also prevent foaming to some extent. This is because if the temperature of the hot high-pressure separator is too low, the viscosity of the liquid phase will increase, making it difficult for small droplets to aggregate into large droplets, thus causing some small droplets to be carried out by the airflow. By appropriately increasing the temperature of the hot high-pressure separator, the viscosity of the liquid phase can be reduced, which can effectively reduce foaming.
[0061] 2. The reaction temperature has a greater impact on the foaming process in the hot high-pressure separator, specifically including:
[0062] When the reaction temperature is low, such as in the initial stage of operation, the diffusion rate of macromolecular gums and asphalt is low, and the reaction is insufficient after contact with the catalyst, which easily leads to foaming. After increasing the reaction temperature, the diffusion rate of gums and asphalt increases and the reaction depth increases, which can greatly reduce the probability of foaming in the hot high-pressure separator.
[0063] It should be noted that, due to the limited space for temperature increase, increasing the reaction temperature will exacerbate side reactions such as hydrogenation condensation, leading to increased coke yield and accelerated deposition on the catalyst, which shortens the catalyst life and is not conducive to long-term operation of the unit. Therefore, in the embodiments of the present invention, it is necessary to control the temperature increase rate and not to increase it too quickly.
[0064] 3. Changes in raw material adjustments (including controlling the slag blending ratio, adjusting the raw material mixing properties, and the type of oil being processed) have the greatest impact on the occurrence of foaming in the hot high-pressure separator, specifically including:
[0065] When adjusting the processing oil type, reducing the proportion of processing oil with low aromatic content can effectively reduce the occurrence of foaming in the hot high-pressure separator; the content of added residue oil will also have a certain impact on foaming, and different residue ratios will lead to different phenomena in the hot high-pressure separator.
[0066] This invention, based on the varying degrees of influence of different factors on foaming in a high-pressure thermal separator, establishes preset rules for determining corresponding foaming control measures based on stability coefficients.
[0067] In one implementation of this invention, the corresponding foaming control measures are determined using formula (1), which may specifically include:
[0068] When the stability coefficient is greater than 2, the oil produced by the reaction can be considered stable, and no adjustment is needed to ensure that the hot high-pressure separator will not produce foam.
[0069] When the stability coefficient is between 1.8 and 2, the oil produced by the reaction is considered to be slightly unstable. The hot high-pressure separator may produce foaming, but it is not serious. Foaming can be prevented by increasing the temperature of the hot high-pressure separator.
[0070] When the stability coefficient is between 1.5 and 1.8, the oil produced by the reaction is considered unstable, and foaming occurs or is about to occur in the hot high-pressure separator. It is necessary to increase the reaction temperature to prevent foaming.
[0071] When the stability coefficient is less than 1.5, it indicates that the oil produced by the reaction is very unstable. It is necessary to control the slag ratio or even adjust the raw material mixing properties or the type of oil to ensure that the hot high-pressure separator does not foam.
[0072] In another implementation of this invention, the corresponding foaming control measures are determined using formulas (2) to (4), which may specifically include:
[0073] First, the stability coefficient is calculated using formula (2). when At this time, the oil produced by the reaction can be considered stable, and no adjustment of operation is required to ensure that the hot high-pressure separator will not foam.
[0074] when When the temperature is between 1.8 and 2, the temperature of the hot high-pressure separator is increased to a first preset temperature. Because the reacted oil is slightly unstable, foaming may occur in the hot high-pressure separator, but it is not severe. This foaming can be prevented by increasing the temperature of the hot high-pressure separator. In practical applications, the first preset temperature can be between 2 and 8°C, preferably between 3 and 5°C.
[0075] In this embodiment of the invention, it is also necessary to further calculate the stability coefficient using formula (3). To determine whether increasing the temperature of the hot high-pressure separator is effective, the calculated stability coefficient should be considered. This indicates that increasing the temperature of the high-pressure thermal separator will lead to a stable state and prevent foaming; if the calculated stability coefficient... This indicates that there is still a possibility of instability even after increasing the temperature of the hot high-pressure separator, therefore further measures are needed, specifically:
[0076] when Between 1.5 and 1.8, or, At that time, the reaction temperature T CAT Increase the second preset temperature; calculate the stability coefficient using formula (4). when When the temperature is between 1.5 and 1.8, the resulting oil is considered unstable, and foaming occurs or is about to occur in the hot high-pressure separator. Therefore, increasing the reaction temperature is necessary to prevent foaming. In this embodiment of the invention, the temperature is increased by T each time. CAT The amplitude (i.e., the second preset temperature) △T CAT The value can range from 0.5 to 5℃, preferably from 1 to 1.5℃.
[0077] In this embodiment of the invention, it is also necessary to further calculate the stability coefficient using formula (4). To determine whether increasing the reaction temperature is effective, if the calculated stability coefficient... This indicates that increasing the reaction temperature will lead to a stable state and prevent foaming; if the calculated stability coefficient... This indicates that even after increasing the reaction temperature, instability may still occur. Therefore, further measures are needed, such as controlling the slag ratio or even adjusting the raw material mixing properties or the type of oil being processed, to ensure that the hot high-pressure separator does not foam. Specifically:
[0078] when or, At that time, foaming can be controlled by reducing the slag ratio or changing the raw materials; when This also indicates that the oil produced by the reaction is very unstable, and it is necessary to control the slag ratio or even adjust the mixing properties of the raw materials or the type of oil to ensure that the hot high-pressure separator does not foam.
[0079] In specific application cases of implementing the embodiments of the present invention, the corresponding foaming control measures are determined using formulas (2) to (4), and the specific process is as follows:
[0080] Application Case (1): The properties of raw materials and products are shown in Tables 1 and 2:
[0081] Table 1: Properties of Raw Materials
[0082] project numerical values Saturated fraction content (wt%) 31.79 Aromatic content (wt%) 44.26 Gum content (wt%) 21.32 Asphalt content (wt%) 2.63
[0083] Table 2: Stream properties between reactor and hot high-pressure separator
[0084] project numerical values Saturated fraction content (wt%) 48.66 Aromatic content (wt%) 34.86 Gum content (wt%) 15.78 Asphalt content (wt%) 0.69
[0085] The reaction conditions for this operating condition are as follows:
[0086] average temperature T of reactor bed CAT The reaction temperature was 360℃, the reaction pressure was 16.5 MPa, the hydrogen-to-oil volume ratio was 680, the temperature of the hot high-pressure separator was 350℃, and the volume hourly space velocity of the feed oil was 0.2 h⁻¹. -1It should be noted that, in this embodiment of the invention, the average temperature of the reactor bed can be simply referred to as the reaction temperature;
[0087] First, formula (2) is used to determine whether foaming will occur in the hot high-pressure separator under this operating condition, and the stability coefficient of the material flow between the reactor and the hot high-pressure separator is calculated. The value is 1.82, indicating that the oil produced by the reaction is unstable. At this point, the temperature of the hot high-pressure separator is increased by 3°C, meaning the temperature of the hot high-pressure separator is now 353°C.
[0088] Next, the new stability coefficient is calculated using formula (3). A value of 1.97 indicates that the oil produced by the reaction is still unstable after increasing the temperature of the hot high-pressure separator, and foaming may occur. In this case, it is necessary to increase the reaction temperature T. CAT To prevent foaming, the reaction temperature is increased by 1°C, i.e., T. CAT It is 361℃;
[0089] Recalculate the new stability coefficient using formula (4). The value is 2.13. At this point, it is determined that the hot high-pressure separator will not produce foaming under this operating condition, and the reaction can be carried out under this condition.
[0090] The actual reaction results show that no foaming phenomenon occurred in the hot high-pressure separator.
[0091] Application Case (2): The properties of raw materials and products are shown in Tables 3 and 4:
[0092] Table 3: Properties of Raw Materials
[0093]
[0094]
[0095] Table 4: Stream properties between reactor and hot high-pressure separator
[0096] project numerical values Saturated fraction content (wt%) 46.88 Aromatic content (wt%) 36.56 Gum content (wt%) 15.85 Asphalt content (wt%) 0.71
[0097] The reaction conditions under this operating condition are as follows: average reactor bed temperature T CAT The reaction temperature was 362℃, the reaction pressure was 16.8 MPa, the hydrogen-to-oil volume ratio was 650, the temperature of the hot high-pressure separator was 350℃, and the volume hourly space velocity of the feed oil was 0.19 h⁻¹. -1 .
[0098] First, formula (2) is used to determine whether foaming will occur in the hot high-pressure separator under this operating condition, and the stability coefficient of the material flow between the reactor and the hot high-pressure separator is calculated. The value is 1.96, indicating that the oil produced by the reaction is unstable.
[0099] The temperature of the hot high-pressure separator is increased by 4℃, that is, the temperature of the hot high-pressure separator is now 354℃. The new stability coefficient is then recalculated using formula (3). The value is 2.12. At this point, it is determined that the hot high-pressure separator will not produce foaming under this operating condition, and the reaction can be carried out under this condition.
[0100] The actual reaction results show that no foaming phenomenon occurred in the hot high-pressure separator.
[0101] Application Case (3): The properties of raw materials and products are shown in Tables 5 and 6:
[0102] Table 5: Properties of Raw Materials
[0103]
[0104]
[0105] Table 6: Stream properties between reactor and hot high-pressure separator
[0106] project numerical values Saturated fraction content (wt%) 45.62 Aromatic content (wt%) 37.82 Gum content (wt%) 15.98 Asphalt content (wt%) 0.58
[0107] The reaction conditions under this condition are as follows: reaction temperature T CAT The reaction temperature was 360℃, the reaction pressure was 16.5 MPa, the hydrogen-to-oil volume ratio was 660, the temperature of the hot high-pressure separator was 349℃, and the volume hourly space velocity of the feed oil was 0.20 h⁻¹. -1 .
[0108] First, formula (2) is used to determine whether foaming will occur in the hot high-pressure separator under this operating condition, and the stability coefficient of the material flow between the reactor and the hot high-pressure separator is calculated. The value is 2.07, indicating that the reaction-generated oil is stable and the hot high-pressure separator will not produce foaming. The reaction can proceed under these conditions.
[0109] The actual reaction results show that no foaming phenomenon occurred in the hot high-pressure separator.
[0110] Application Case (4): The properties of raw materials and products are shown in Tables 7 and 8:
[0111] Table 7: Properties of Raw Materials
[0112] project numerical values Saturated fraction content (wt%) 33.54 Aromatic content (wt%) 41.90 Gum content (wt%) 20.35 Asphalt content (wt%) 4.21
[0113] Table 8: Stream properties between reactor and hot high-pressure separator
[0114] project numerical values Saturated fraction content (wt%) 51.92 Aromatic content (wt%) 30.73 Gum content (wt%) 15.52 Asphalt content (wt%) 1.83
[0115] The reaction conditions under this condition are as follows: reaction temperature TCAT The reaction temperature was 360℃, the reaction pressure was 16.5 MPa, the hydrogen-to-oil volume ratio was 670, the temperature of the hot high-pressure separator was 350℃, and the volume hourly space velocity of the feed oil was 0.20 h⁻¹. -1 .
[0116] First, formula (2) is used to determine whether foaming will occur in the hot high-pressure separator under this operating condition, and the stability coefficient of the material flow between the reactor and the hot high-pressure separator is calculated. The value is 1.53. At this point, the resulting oil is considered unstable, and foaming needs to be prevented by increasing the reaction temperature. The reaction temperature is increased by 1.5℃, i.e., T... CAT The temperature was 361.5℃.
[0117] Recalculate the new stability coefficient using formula (4). The value is 1.91, which is still less than 2. After continuing processing under this condition, foaming was found in the hot high-pressure separator, which affected the stable operation of the downstream equipment. Therefore, it was determined that the raw materials needed to be adjusted and replaced to ensure that the hot high-pressure separator would not produce foaming.
[0118] In practical applications, the specific structure and working principle of the fixed-bed residue hydrotreating reaction system in this embodiment of the invention can be as follows:
[0119] In the embodiments of the present invention, the hydrogenation pretreatment reactor in the hydrogenation pretreatment reaction zone can be filled with one or more of a hydrogenation protective agent and a hydrogenation demetallization catalyst. Preferably, the hydrogenation pretreatment reactor is provided with a hydrogenation protective agent bed and a hydrogenation demetallization catalyst bed. The hydrogenation protective agent bed is filled with a hydrogenation protective agent, and the hydrogenation demetallization catalyst bed is filled with a hydrogenation demetallization catalyst. The aforementioned hydrogenation protective agent and hydrogenation demetallization catalyst generally use porous refractory inorganic oxides such as alumina as a support, and one or more of oxides of Group VIB and / or Group VIII metals such as W, Mo, Co, Ni, etc., as active components, and selectively add at least one of various other auxiliary agents such as P, Si, F, B, etc.
[0120] In the hydrotreating reaction zone of this invention, conventionally used hydrotreating catalysts in the art can be loaded, and one or more combinations of hydrodesulfurization catalysts, hydrodenitrogenation catalysts, and decarbonization conversion catalysts can be selected. These catalysts generally use porous, refractory inorganic oxides such as alumina as a support, and oxides of Group VIB and / or Group VIII metals such as W, Mo, Co, Ni, etc., as the active component. For example, the FZC series residue hydrotreating catalysts produced by the Catalyst Division of China Petroleum & Chemical Corporation (Sinopec) are used. The loading sequence is generally to sequentially contact the feedstock with the hydroprotective agent, hydrodemetallization catalyst, hydrodesulfurization catalyst, and hydrodenitrogenation catalyst, or to mix and load these catalysts together.
[0121] The operating conditions of the hydrotreating reaction zone in this embodiment of the invention are as follows: reaction temperature of 320–420°C, reaction pressure of 10 MPa–25 MPa, hydrogen-to-oil volume ratio of 300–1500, and feedstock oil volume hourly space velocity of 0.15 h⁻¹. -1 ~2.0h -1 Preferably, the reaction temperature is 350–400℃, the reaction pressure is 15 MPa–25 MPa, the hydrogen-to-oil volume ratio is 500–800, and the feedstock oil volume hourly space velocity is 0.3 h⁻¹. -1 ~1.0h -1 .
[0122] The operating conditions of the hydrotreating reaction zone in this embodiment of the invention are as follows: reaction temperature of 345–420°C, reaction pressure of 10 MPa–25 MPa, hydrogen-to-oil volume ratio of 300–1500, and feedstock oil volume hourly space velocity of 0.15 h⁻¹. -1 ~0.80h -1 Preferably, the reaction temperature is 355–410℃, the reaction pressure is 15 MPa–25 MPa, the hydrogen-to-oil volume ratio is 400–800, and the feedstock oil volume hourly space velocity is 0.2 h⁻¹. -1 ~0.6h -1 .
[0123] The residue feedstock in this embodiment of the invention is atmospheric residue and / or vacuum residue, which may or may not contain one or more of straight-run wax oil, vacuum wax oil, secondary processed wax oil, and catalytic recycle oil. The residue feedstock has the following properties: sulfur content not exceeding 4 wt%, nitrogen content not exceeding 0.7 wt%, metal content (Ni+V) not exceeding 120 μg / g, carbon residue not exceeding 17 wt%, and asphaltenes content not exceeding 5 wt%.
[0124] In summary, this embodiment of the invention samples the reaction-generated oil in the connection pipeline between the last hydrotreating reactor and the hot high-pressure separator, and obtains the content of the four components of the sampled oil. Then, the stability coefficient of the reaction-generated oil is calculated. In this way, based on preset rules, the stability coefficient can be used to predict whether high-level foaming will occur and its cause, and then determine the corresponding foaming control measures. This allows for preventive operations to be performed before foaming occurs in the hot high-pressure separator. Since this embodiment of the invention can effectively avoid the occurrence of high-level foaming, it can ensure the normal operation of the device and the stability of downstream devices.
[0125] Example 2
[0126] Furthermore, based on Embodiment 1, this embodiment of the invention also provides a foaming control device for a fixed-bed residue hydrotreating system. This foaming control device is used to implement the foaming control method for a fixed-bed residue hydrotreating system described in Embodiment 1; see reference. Figure 2 The foaming control device includes a sampler 04 for extracting sample oil from the reaction-generated oil. The sampler 04 is located on the connecting pipeline between the last hydrotreating reactor 21 and the hot high-pressure separator 31.
[0127] A chromatographic analyzer (not shown in the figure) is used to obtain the content of four components in the reaction-generated oil; the content of the four components includes aromatic content, gum content, saturated content and asphaltenes content;
[0128] The data processing module (such as a computer device, not shown in the figure) is used to calculate the stability coefficient of the reaction-generated oil based on the content of the four components, and to determine the corresponding foaming control measures according to preset rules using the stability coefficient as a parameter; the foaming control measures include no adjustment required, increasing the temperature of the hot high-pressure separator, increasing the reaction temperature, and adjusting the raw materials.
[0129] In a typical application scenario of this invention, the fixed-bed residue hydrotreating system includes a hydrotreating pretreatment reaction zone 01, a hydrotreating reaction zone 02, and a fractionation zone 03. The hydrotreating pretreatment reaction zone 01 includes multiple hydrotreating reactors; the hydrotreating reaction zone 02 includes multiple hydrotreating reactors; and the fractionation zone 03 includes a hot high-pressure separator 31, a cold high-pressure separator 32, a hot low-pressure separator 33, and a cold low-pressure separator 34. In practical applications, the multiple hydrotreating reactors may specifically include 2 or 3 hydrotreating reactors connected in series. The multiple hydrotreating reactors may specifically include 2 to 5 hydrotreating reactors connected in series.
[0130] To obtain the content of the four components in the reaction-generated oil, this embodiment of the invention can add a side line to the pipeline between the last reactor 21 and the hot high-pressure separator 31, and set up a detection device for online detection of the content of the four components in the reaction-generated oil. The detection device may include a sample sampler 04 for extracting sample oil from the reaction-generated oil and a chromatograph; preferably, the chromatograph may be a rod-shaped thin-layer chromatograph or a gel permeation chromatograph. In this way, after the chromatographic rod is inserted into the inlet of the chromatograph, scanning begins, and the peak area calculation can be automatically completed by a data processing module (such as a computer device) to calculate the percentage content of each component.
[0131] This invention, based on the varying degrees of influence of different factors on foaming in a high-pressure thermal separator, establishes preset rules for determining corresponding foaming control measures based on stability coefficients.
[0132] In one implementation of this invention, the corresponding foaming control measures are determined using formula (1), which may specifically include:
[0133] When the stability coefficient is greater than 2, the oil produced by the reaction can be considered stable, and no adjustment is needed to ensure that the hot high-pressure separator will not produce foam.
[0134] When the stability coefficient is between 1.8 and 2, the oil produced by the reaction is considered to be slightly unstable. The hot high-pressure separator may produce foaming, but it is not serious. Foaming can be prevented by increasing the temperature of the hot high-pressure separator.
[0135] When the stability coefficient is between 1.5 and 1.8, the oil produced by the reaction is considered unstable, and foaming occurs or is about to occur in the hot high-pressure separator. It is necessary to increase the reaction temperature to prevent foaming from occurring.
[0136] When the stability coefficient is less than 1.5, it indicates that the oil produced by the reaction is very unstable. It is necessary to control the slag ratio or even adjust the raw material mixing properties or the type of oil to ensure that the hot high-pressure separator does not foam.
[0137] In another implementation of this invention, the corresponding foaming control measures are determined using formulas (2) to (4), which may specifically include:
[0138] First, the stability coefficient is calculated using formula (2). when At this point, the oil produced by the reaction can be considered stable, and the hot high-pressure separator can be maintained without any adjustment to the operation.
[0139] when When the temperature is between 1.8 and 2, the temperature of the hot high-pressure separator is increased to a first preset temperature. Because the reacted oil is slightly unstable, foaming may occur in the hot high-pressure separator, but it is not severe. This foaming can be prevented by increasing the temperature of the hot high-pressure separator. In practical applications, the first preset temperature can be between 2 and 8°C, preferably between 3 and 5°C.
[0140] In this embodiment of the invention, it is also necessary to further calculate the stability coefficient using formula (3). To determine whether increasing the temperature of the hot high-pressure separator is effective, the calculated stability coefficient should be considered. This indicates that increasing the temperature of the high-pressure thermal separator will lead to a stable state and prevent foaming; if the calculated stability coefficient... This indicates that there is still a possibility of instability even after increasing the temperature of the hot high-pressure separator, therefore further measures are needed, specifically:
[0141] when Between 1.5 and 1.8, or, At that time, the reaction temperature T CAT Increase the second preset temperature; calculate the stability coefficient using formula (4). when When the temperature is between 1.5 and 1.8, the resulting oil is considered unstable, and foaming occurs or is about to occur in the hot high-pressure separator. Therefore, increasing the reaction temperature is necessary to prevent foaming. In this embodiment of the invention, the temperature is increased each time T... CAT The amplitude (i.e., the second preset temperature) △T CAT The value can range from 0.5 to 5℃, preferably from 1 to 1.5℃.
[0142] In this embodiment of the invention, it is also necessary to further calculate the stability coefficient using formula (4). To determine whether increasing the reaction temperature is effective, if the calculated stability coefficient... A value greater than 2 indicates that increasing the reaction temperature will lead to a stable state and prevent foaming. If the calculated stability coefficient is... This indicates that even after increasing the reaction temperature, there is still a possibility of instability. Therefore, further measures are needed, such as controlling the slag ratio or even adjusting the raw material mixing properties or the type of oil being processed, to ensure that the hot high-pressure separator does not foam. Specifically:
[0143] when or, At that time, foaming can be controlled by reducing the slag ratio or changing the raw materials; when This also indicates that the oil produced by the reaction is very unstable, and it is necessary to control the slag ratio or even adjust the mixing properties of the raw materials or the type of oil to ensure that the hot high-pressure separator does not foam.
[0144] Since the working principle and beneficial effects of the foam control device for the fixed-bed residue hydrotreating system in the embodiments of the present invention have been already understood, Figure 1 The corresponding foaming control methods for fixed-bed residue hydrotreating reaction systems are also described and explained, so they can be referenced together and will not be repeated here.
[0145] The above-described product can execute the methods provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the methods. Technical details not described in detail in this embodiment can be found in the methods provided in other embodiments of the present invention.
[0146] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for controlling foaming in a fixed-bed residue hydrotreating system, the fixed-bed residue hydrotreating system comprising a hydrotreating pretreatment reaction zone, a hydrotreating reaction zone, and a fractionation zone; the hydrotreating pretreatment reaction zone comprising multiple hydrotreating reactors; the hydrotreating reaction zone comprising multiple hydrotreating reactors; the fractionation zone comprising a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator, and a cold low-pressure separator; characterized in that, Including the following steps: S11. Obtain the content of the four components of the oil produced in the reaction in the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator; the content of the four components includes the content of aromatics, gums, saturates and asphaltenes. S12. The stability coefficient of the reaction-generated oil is calculated based on the content of the four components in the reaction-generated oil. S13. Using the stability coefficient as a parameter, determine the corresponding foaming control measures according to preset rules; the foaming control measures include no adjustment required, increasing the temperature of the hot high-pressure separator, increasing the reaction temperature, and adjusting the raw materials.
2. The foaming control method for a fixed-bed residue hydrotreating system according to claim 1, characterized in that, The process of obtaining the four-component content of the reaction-generated oil in the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator includes: Sample oil of the reaction-generated oil is extracted by a sampler located on the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator. The content of the four components of the oil produced by the reaction was obtained by chromatographic analysis.
3. The foaming control method for a fixed-bed residue hydrotreating system according to claim 2, characterized in that, The chromatographic analyzer includes: Rod-shaped thin-layer chromatograph or gel permeation chromatograph.
4. The foaming control method for a fixed-bed residue hydrotreating system according to claim 3, characterized in that, The sample amount of the oil is 10 μg to 0.1 g; the oil is spotted 1 to 3 cm from the top of the rod-shaped thin-layer chromatograph.
5. The foaming control method for a fixed-bed residue hydrotreating system according to claim 4, characterized in that, The amount of the sample oil taken is 10 μg to 100 μg; the sample oil is spotted 2 cm from the top of the rod-shaped thin-layer chromatograph.
6. The foaming control method for a fixed-bed residue hydrotreating system according to claim 5, characterized in that, The step of obtaining the four-component content of the reaction-generated oil in the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator includes: The sample oil was spotted onto a rod-shaped thin-layer chromatograph, and after the solvent was removed by evaporation at room temperature, it was placed in a developing tank containing n-heptane for development. When n-heptane carrying saturated hydrocarbons moves to a position of 10-13 cm, remove the rod rack and dry it for 10 minutes before placing it in a developing tank containing toluene. After the toluene carrying the aromatic components moves to a position of 8-9 cm, remove the rod rack and dry it for 10 minutes before placing it in a developing tank containing dichloromethane. When the solvent of dichloromethane and methanol carries the colloid to a depth of 4-5 cm, remove the rod and dry it for 10 minutes. After inserting the chromatographic rod into the inlet of the chromatograph, scanning begins, and the percentage content of each component is calculated by peak area.
7. The foaming control method for a fixed-bed residue hydrotreating system according to claim 1, characterized in that, The raw material adjustment includes: Controlling the slag blending ratio, adjusting the mixing properties of raw materials, or processing one or more types of oil.
8. The foaming control method for a fixed-bed residue hydrotreating system according to any one of claims 1 to 7, characterized in that, The formulas for calculating the stability coefficient include: Stability coefficient = (aromatic content wt / % + resin content wt / %) / (saturated content wt / % + asphaltene content wt / %), formula (1); The preset rules include: when No operation adjustment is required at this time; when When the temperature is between 1.8 and 2, foaming can be controlled by increasing the temperature of the hot high-pressure separator. when When the temperature is between 1.5 and 1.8, foaming can be controlled by increasing the reaction temperature; when At that time, foaming was controlled by adjusting the raw materials.
9. The foaming control method for a fixed-bed residue hydrotreating system according to any one of claims 1 to 7, characterized in that, The formulas for calculating the stability coefficient include: Among them, T CAT This represents the average temperature of the reactor bed; the correction factor K0 is set to 1.
51. The correction factor K1 is set to 1.63; The value of the correction factor K2 is: K2 = 1.51 + ΔT CAT / 4; where △T CAT The reaction temperature T CAT The extent of the increase; The preset rules include: The stability coefficient is calculated using formula (2). when No operation adjustment is required at this time; when When the temperature is between 1.8 and 2, the temperature of the hot high-pressure separator is increased to the first preset temperature; the stability coefficient is calculated using formula (3). when Between 1.5 and 1.8, or, At that time, the reaction temperature T CAT Increase the second preset temperature; calculate the stability coefficient using formula (4). when or, At the same time, foaming can be controlled by reducing the slag ratio or changing the raw materials.
10. The foaming control method for a fixed-bed residue hydrotreating system according to claim 1, characterized in that, The plurality of hydrogenation pretreatment reactors include: It includes two or three hydrogenation pretreatment reactors connected in series.
11. The foaming control method for a fixed-bed residue hydrotreating system according to claim 10, characterized in that, The plurality of hydrogenation reactors include: It includes 2 to 5 hydrogenation pretreatment reactors connected in series.
12. A foaming control device for a fixed-bed residue hydrotreating system, characterized in that, The fixed-bed residue hydrotreating reaction system includes a hydrotreating pretreatment reaction zone, a hydrotreating reaction zone, and a fractionation zone; the hydrotreating pretreatment reaction zone includes multiple hydrotreating reactors; the hydrotreating reaction zone includes multiple hydrotreating reactors; the fractionation zone includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator, and a cold low-pressure separator; characterized in that the foaming control device includes: A sampler for extracting sample oil from the reaction-generated oil is located on the connecting pipeline between the last hydrotreating reactor and the hot high-pressure separator. The chromatographic analyzer is used to obtain the content of four components in the reaction-generated oil; the content of the four components includes aromatic content, gum content, saturated content and asphaltenes content; The data processing module is used to calculate the stability coefficient of the reaction-generated oil based on the content of the four components, and to determine the corresponding foaming control measures according to preset rules using the stability coefficient as a parameter; the foaming control measures include no adjustment required, increasing the temperature of the hot high-pressure separator, increasing the reaction temperature, and adjusting the raw materials.
13. The foaming control device for a fixed-bed residue hydrotreating system according to claim 12, characterized in that, The chromatographic analyzer includes: Rod-shaped thin-layer chromatograph or gel permeation chromatograph.