Device and method for producing foaming agent raw material from pentane fraction in catalytic reforming device

Abstract

The invention discloses a method and a device for producing a foaming agent raw material from pentane fraction in a catalytic reforming device. The method comprises the following steps: reformate is subjected to liquid-phase hydrotreating, hydrogenated reformate and residual hydrogen enter a depentanizer for fractionation, a hydrogenation reaction unit is additionally arranged in front of a reflow tank at the top of the depentanizer, materials at the top of the depentanizer are subjected to heat exchange and temperature rise and then enter a reactor for hydrogenation, hydrogenation products enter a subsequent C4 / C5 fractionating tower, and the materials at the top of the depentanizer are subjected to fractionation. The C5 fraction obtained at the tower bottom can be directly used as a raw material for producing a pentane foaming agent. According to the method, the pentane fraction hydrogenation process flow is greatly simplified, the device investment and the operation cost are reduced, and the problem that the material temperature at the top of the pentane removal tower cannot meet the hydrogenation reaction requirement in the initial stage of starting and the normal production period is effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogenation, and relates to a device and method for producing foaming agent raw materials from pentane fraction of a catalytic reforming device. Specifically, a pentane fraction processing unit of a reforming device is embedded in the reforming device, and is particularly suitable for a reforming device that needs to produce foaming agent raw materials. Background Art

[0002] Light naphtha from the reforming unit is a very valuable petroleum resource. Its components are relatively light and are basically saturated alkanes, of which C3 and C4 components account for about 40% to 50%, C5 components account for 50% to 60%, and the rest are trace C5+ components. Saturated carbon pentahydrocarbons n-pentane, isopentane and cyclopentane are widely used in the industrial field. Isopentane can be used as a solvent for catalysts for the synthesis of polyethylene, a foaming agent for expandable polystyrene, a foaming agent for polyurethane foam systems, and a solvent for deasphalting; isopentane is also an important basic chemical raw material, such as the production of isopentanol and isoprene. N-pentane can be used as a desorbent in the molecular sieve dewaxing process. It can meet the requirements of different foaming degrees after being blended with isopentane in different proportions, and can completely replace imported products; a mixture of n-pentane and isopentane can be used as a catalyst for polyethylene; n-pentane is also used as a chemical raw material to produce n-pentanol, n-valeraldehyde, etc. At present, non-toxic, odorless, clean, low-carbon and low-sulfur saturated hydrocarbons in single or mixed components with certain volatility are receiving more and more attention. The hydrocarbon aerosols, foaming agents, solvent oils, etc. further developed from these saturated hydrocarbons are widely used in the cosmetics, fragrances, rubber, plastics, oils and other industries.

[0003] With the increasing global refining capacity, the output of light naphtha has also increased significantly. How to reasonably utilize the light naphtha of the reforming unit has become an important issue in industrial production. At present, light naphtha is often used as a gasoline blending component or a raw material for aromatization units. However, since light naphtha is rich in C4-C6 alkanes, directly blending it into gasoline will reduce the gasoline octane number and increase the gasoline vapor pressure. Aromatization of light naphtha requires the construction of new equipment, which increases investment costs. However, since light naphtha is rich in C5 alkanes, this part of the raw material can be used to produce high-purity pentane oil, namely pentane foaming agent. Foaming agent is a substance that promotes the generation of foam to form closed-cell or intercellular structure materials, also known as foaming agent or foaming agent. Traditional chlorofluorocarbon foaming agents are gradually abandoned due to environmental pollution problems, while pentane foaming agents can be used as chlorofluorocarbon substitutes to meet various environmental protection requirements due to their advantages such as low greenhouse effect potential (GWP), low toxicity, safety and environmental protection. From the perspective of the physical and chemical properties of the foaming agent, the reforming unit is very suitable as a device for producing high-purity pentane foaming agent. The reforming pre-hydrogenation reactor removes impurities such as sulfur, nitrogen, and oxygen from naphtha, and after separation by the fractionation unit, high-quality pentane foaming agent can be obtained.

[0004] In recent years, China's oil refining industry has rapidly expanded its scale of refining and increased its production capacity through a combination of expansion and renovation and new construction. The fuel oil market has become increasingly saturated, and the contradiction of overcapacity has become increasingly prominent. In addition, with the rapid development of new energy vehicles, the demand for gasoline is expected to decline, and some companies have difficulty in gasoline delivery. Light naphtha, as an oil blending component, will reduce the octane number of gasoline and increase the saturated vapor pressure of gasoline, which has a greater impact in summer. Against this background, many domestic refining and chemical companies have further optimized the use of light naphtha through process flow adjustment, processing plan adjustment, and new equipment construction. For example, a 2.6 million tons / year naphtha hydrogenation unit of a China National Petroleum Corporation and a 300,000 tons / year naphtha hydrogenation unit of a Sinopec company use light naphtha to produce pentane foaming agents, achieving good economic and social benefits.

[0005] CN111362773A discloses a device and process for preparing pentane foaming agent by reforming topped naphtha. In this method, a feed buffer tank is connected to a deisopentane tower, and the top of the deisopentane tower is connected to the bottom of a public distillation tower; a baffle tower is provided inside the deisopentane tower, the upper side line of the deisopentane tower is connected to an isopentane product tank, and the middle side line of the deisopentane tower is connected to a foaming agent tank; the bottom of the public distillation tower is connected to the top of the deisopentane tower through a public distillation tower feed pump. The present invention omits the reaction section and the subsequent fractionation section, and has obvious energy-saving effect; in addition, the process adopts baffle distillation process technology, and the operation that can only be completed by two fractionation towers is completed by one fractionation tower, saving equipment investment. However, compared with the method of the present invention, the raw material processed by the method is light naphtha obtained from the reforming pre-hydrogenation device, while the method of the present invention processes light naphtha from the top of the depentane tower of the reforming device, and the processed raw materials and properties are completely different.

[0006] CN104557392B discloses a method for producing pentane. Using carbon five after etherification as raw material, hydrogenation and removal of residual olefins are performed to produce a pentane product with a qualified pentane bromide index. After the carbon five after etherification and hydrogen are mixed, a hydrogenation reaction is carried out through a fixed bed catalyst bed, and the catalyst is a Ni / diatomaceous earth catalyst. The hydrogenated product passes through a fixed bed of a strong acid cation exchange resin at a temperature of 10 to 40°C to remove residual unsaturated hydrocarbons. The raw materials processed by this method are completely different from those of the present invention, and the catalysts and reaction mechanisms used are also quite different. In addition, a new set of independent hydrogenation equipment needs to be built, and the investment and operating costs are relatively high. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a device and method for producing foaming agent raw materials from pentane fractions of a catalytic reforming device. By optimizing the combination of a pentane hydrotreating device and a reforming device, not only can the various indicators of pentane generated oil after hydrogenation meet the requirements for producing foaming agents, but the investment, energy consumption, and operating costs are greatly reduced compared with the existing devices, and at the same time, the problem of unqualified product quality caused by unsatisfactory operating conditions in the initial start-up of the hydrogenation unit and during the production process is solved.

[0008] According to a first aspect of the present invention, there is provided an apparatus for producing a foaming agent raw material from a pentane fraction of a catalytic reforming unit.

[0009] Specifically, a device for producing a foaming agent raw material from a pentane fraction of a catalytic reforming device is characterized in that the device comprises: Depentanizer, which is used to fractionate the reformed oil product into C4 / C5 fraction and C6 + (i.e. C6 and above) fraction; the depentanizer comprises a feed pipeline for feeding the reformed oil hydrogenation product to the depentanizer, a bottom take-off device for removing the C6+ fraction, and a top take-off device for removing the top product pentane fraction; A pentane hydrogenation reactor, in which the pentane fraction is contacted with hydrogen to carry out a hydrogenation reaction; the hydrogenation reactor comprises a hydrogenation catalyst bed; the inlet of the hydrogenation reactor is connected to the tower top removal device via a first heat exchanger; the outlet of the hydrogenation reactor is connected to the gas-liquid separator through a pipeline after passing through the first heat exchanger and an air cooler; a first heat exchanger in which the pentane fraction is heat exchanged with a hydrogenation reactor effluent; A gas-liquid separator, in which the hydrogenation reaction effluent after cooling is separated into gas and liquid products; the liquid outlet of the gas-liquid separator is respectively connected to the top liquid phase reflux inlet of the depentanizer and the feed inlet of the C4 / C5 fractionator.

[0010] Furthermore, the depentanizer is provided with a tower top gas reflux port at a position higher than the liquid phase reflux port, and the outlet of the pentane hydrogenation reactor is connected to the tower top gas reflux port through a pipeline after passing through the first heat exchanger. Furthermore, a valve is provided on the pipeline to control the flow rate of the tower top gas reflux.

[0011] Furthermore, the device also includes a C4 / C5 fractionation tower, in which the C4 / C5 fraction obtained from the gas-liquid separator is fractionated into C4 and C5 fractions.

[0012] Furthermore, the device also includes a reformed oil hydrogenation reactor, which is used to hydrogenate the reformed oil fraction; the outlet of the reformed oil hydrogenation reactor is connected to the feed inlet of the depentanizer.

[0013] Furthermore, after the outlet of the pentane hydrogenation reactor passes through the first heat exchanger, a valve is provided on the connecting pipeline with the air cooler to control the flow of the material entering the gas-liquid separator through the air cooler.

[0014] According to a second aspect of the present invention, there is provided a method for producing a foaming agent raw material from a pentane fraction in a catalytic reforming unit.

[0015] The method for producing a foaming agent raw material from a pentane fraction of a catalytic reforming device comprises the following steps: (1) The reforming oil product enters the depentanizer, and the pentane fraction is obtained at the top of the tower, and the C6 + fractions; (2) providing a pentane hydrogenation reactor; the pentane fraction obtained in step (1) is mixed with optional supplemental hydrogen, and after heat exchange with the pentane fraction hydrogenation product in a first heat exchanger, enters the pentane fraction hydrogenation reactor and passes through a hydrogenation catalyst bed under hydrogenation conditions; (3) The hydrogenation product of the pentane fraction after cooling in the first heat exchanger is divided into two paths, one of which is returned to the upper tray of the depentanizer through the gas phase reflux port; (4) Another path of the pentane fraction hydrogenation product after cooling in the first heat exchanger enters the gas-liquid separator after further cooling to obtain a gas phase product and a C4 / C5 liquid phase product; (5) The C4 / C5 liquid product obtained in step (4) is divided into two paths, one path enters the downstream C4 / C5 fractionation tower, and the other path is used as liquid reflux and returns to the upper part of the depentanizer through the liquid reflux port.

[0016] Furthermore, the reformed oil product in step (1) may be a hydrogenation product obtained by hydrogenating the reformed oil fraction (which contains unreacted hydrogen or dissolved hydrogen), or may be a product obtained by refining the reformed oil fraction with white clay.

[0017] Furthermore, the position (gas phase reflux port) at which the pentane fraction hydrogenation product obtained in step (3) returns to the depentanizer is higher than the position (liquid phase reflux port) at which the C4 / C5 liquid phase product obtained in step (4) returns to the depentanizer. Preferably, the position at which the pentane fraction hydrogenation product returns to the depentanizer is 1-5 trays higher than the position at which the C4 / C5 liquid phase product returns to the depentanizer. By setting the position at which the pentane fraction hydrogenation product returns to the depentanizer to be higher than the position at which the C4 / C5 liquid phase product obtained in step (4) returns to the depentanizer, a portion of the pentane fraction hydrogenation product that passes through the first heat exchanger can enter the depentanizer again, and be further heated in the depentanizer, and after being removed from the top of the tower, it is equivalent to raising the inlet feed temperature of the pentane hydrogenation reactor, which helps to obtain the minimum temperature of the hydrogenation reaction as soon as possible at the initial start-up. After normal operation, the reflux amount of the pentane fraction hydrogenation product can be appropriately reduced by adjusting the valve opening.

[0018] Furthermore, the depentane tower in step (1) adopts conventional operating conditions in the art. The operating conditions generally include: tower top temperature of 80-120°C, tower bottom temperature of 180-225°C, and operating pressure of 0.8-1.2 MPa.

[0019] Furthermore, the hydrogenation conditions described in step (2) include: the reaction pressure is generally 0.5 MPa to 6.0 MPa, preferably 0.8 MPa to 2.0 MPa. The reaction pressure is usually determined according to the pressure at the top of the depentanizer, and generally does not need to be adjusted, but can be appropriately adjusted as needed. The reaction temperature is generally 80°C to 200°C, preferably 100°C to 160°C. The liquid phase volume space velocity is 1.0 h -1 ~15. 0h -1 , preferably 4.0 h -1 ~10.0 h -1 The volume ratio of hydrogen to oil is 0 to 20:1 (since the top material of the depentanizer contains dissolved hydrogen, the additional hydrogen introduced can be 0), preferably 3 to 8:1. In the present invention, the volume ratio of hydrogen to oil can be significantly reduced compared with the existing conventional method.

[0020] Furthermore, the hydrorefining catalyst described in step (2) may be a conventional hydrorefining catalyst or a hydrotreating catalyst in the art. The hydrorefining catalyst may be a commercial hydrorefining catalyst, such as a hydrorefining catalyst with a noble metal or reduced nickel as an active component. Such a catalyst has a high hydrogenation activity and can carry out a hydrogenation reaction at a relatively low temperature. Preferably, a hydrorefining catalyst with a medium noble metal as an active component is used, such as the FHDA-10 catalyst developed and produced by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. The noble metal hydrorefining catalyst generally uses alumina as a carrier and Pt and / or Pd as an active component. The content of the active component in the catalyst by weight is not less than 0.1%, generally 0.1% to 1.5%. For the hydrorefining catalyst with reduced nickel as the active component, generally alumina or modified alumina is used as the carrier, and nickel oxide is used as the active component (the weight of nickel oxide accounts for 15% to 70% of the weight of the catalyst, preferably 25% to 45%). The catalyst is reduced and activated before use to convert the nickel oxide into a reduced state to improve the hydrogenation activity of the catalyst. For the reformed oil pentane fraction raw material, the use of the hydrorefining catalyst can make the bromine index of the reformed oil pentane fraction less than 100 mgBr / 100g, meeting the index requirements for the production of foaming agent raw materials.

[0021] Furthermore, the volume ratio of the C5 fraction hydrogenation product returned to the upper part of the depentanizer in step (3) to the C5 fraction hydrogenation product entering the gas-liquid separator in step (4) is generally 1:4-1:1.

[0022] Furthermore, the mass fraction of the liquid reflux material in the C4 / C5 liquid product obtained in step (4) is 10-50% of the total C4 / C5 liquid product.

[0023] In the present invention, a pipeline connecting the outlet of the pentane hydrogenation reactor to the gas reflux port on the top of the depentanizer is preferably provided. When the pentane hydrogenation reactor is started, the materials at the outlet of the pentane hydrogenation reactor are first all returned to the depentanizer for heat exchange and temperature increase. The materials are fully refluxed in the gas phase. After 5 minutes to 24 hours, preferably 1 to 10 hours, when the temperature of the top material (containing hydrogen) of the depentanizer reaches the operating conditions required for pentane hydrogenation and the temperature of the hydrogenation product is significantly increased, the valve for returning the pentane hydrogenation product to the depentanizer is gradually partially or completely closed, and the pentane refined oil gradually enters the downstream cooler and the gas-liquid separator, and the pentane hydrogenation unit enters the normal production stage.

[0024] In the present invention, the pentane hydrogenation reactor is arranged between the top outlet of the depentanizer and the cooler, and the material (containing hydrogen) discharged from the top of the depentanizer enters the hydrogenation reactor after passing through the heat exchanger. The pentane hydrogenation reactor adopts an upper feeding operation mode, that is, the reaction material enters the reactor from the upper part of the hydrogenation reactor for hydrogenation reaction, and the refined oil enters the C4 / C5 separation unit after cooling and separation, and the C5 fraction can be directly used to produce foaming agent raw materials. The pentane hydrogenation reactor can also adopt a downflow operation mode, that is, the reaction material enters the reactor from the bottom of the hydrogenation reactor for hydrogenation reaction. The pentane hydrogenation reactor adopts a gas phase reaction state, that is, under the reaction conditions, most of the pentane fraction is in a gas phase state. A material conveying device is arranged at the bottom of the pentane hydrogenation reactor, and the pentane generated oil is partially or completely conveyed to the inlet at the corresponding position of the top of the depentanizer through the material conveying device. The depentanizer is generally provided with a bottom reboiler to provide a heat source for the depentanizer. When the pentane fraction hydrogenation reactor is started up, part or all of the top material of the depentanizer is returned to the top of the depentanizer.

[0025] The pentane fraction of the present invention is the top fraction of the oil depentane tower generated by the reforming device.

[0026] In the present invention, in order to ensure that the C5 fraction hydrogenation product is refluxed through the tower to increase the feed temperature of the C5 fraction hydrogenation reactor, while not affecting the fractionation accuracy of the original depentanizer, the operating pressure of the depentanizer should be appropriately increased. Preferably, the operating pressure of the depentanizer can be increased by 0.1-1.0 MPa; most preferably, the operating pressure of the depentanizer is increased by 0.2-0.5 MPa.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. Although the reforming oil has been hydrotreated before entering the depentanizer, the bromine index of the separated pentane fraction is still relatively high, generally reaching several thousand or even tens of thousands. For reforming units with higher severity, the bromine index of the pentane fraction is even higher. If it is used as a raw material for producing foaming agents, it must be further processed. Generally speaking, the use of hydrotreatment can make the refined products meet the requirements, but the required reaction conditions must be met in order to make the properties of the pentane production oil meet the requirements for producing foaming agent raw materials. However, the reaction temperature at the top of the reforming unit's depentanizer is significantly low, and the reaction materials need to be increased by at least 10~25℃. By setting up a pipeline and corresponding valves for the pentane production oil to return to the depentanizer, the problem of unqualified properties of the pentane production oil caused by substandard reaction conditions is completely solved, and it has the advantages of short start-up time and no unqualified products leaving the unit. In the present invention, the pipeline and corresponding valve design of the pentane generated oil returning to the depentanizer are cleverly adopted, and combined with the actual characteristics of the device, that is, the pressure at the top of the depentanizer is relatively appropriate, but the temperature is low, the pentane generated oil gas phase material is partially or completely returned to the depentanizer, so that the material can fully obtain the required heat, meet the requirements of the reaction conditions, and solve the problem of unqualified properties of pentane refined oil. The present invention has a clever concept, a simple process flow, is easy to implement, has a low maintenance cost, and effectively avoids the problem of unqualified product quality.

[0028] 2. Under the premise of satisfying the system pressure balance and the pressure required for the hydrogenation reaction, the present invention makes full use of the surplus hydrogen at the top of the depentanizer as raw hydrogen. Compared with the pentane raw material entering the hydrogenation reactor from the upper part of the reactor, the process flow is greatly simplified and the investment cost is reduced. At the same time, when the hydrogenation unit is started, due to the low temperature at the top of the tower, the requirements of the hydrogenation reaction cannot be met. First, all the materials at the outlet of the pentane hydrogenation reactor are introduced into the depentanizer, so that the temperature of the top pentane fraction is raised to the operating conditions required for the hydrogenation reaction, so that the hydrogenation reactor and the hydrogenation catalyst can quickly reach the optimal state required for the reaction, and the problem of the properties of the hydrogenation reaction products failing to meet the indicators when the device is started will not be caused. This method makes the process method more flexible and will not affect the normal operation of the subsequent foaming agent production device due to the process method. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figure is a specific flow chart of the method of the present invention.

[0030] In the figure, the numerical marks correspond to: 10-depentanizer, 11-reforming oil hydrogenation product feed pipeline, 12-tower top removal device, 13-tower bottom removal device, 14-supplementary hydrogen pipeline, 15-liquid phase reflux port, 16-gas phase reflux port, 20-first heat exchanger, 30-pentane hydrogenation reactor, 31-pipeline, 311 / 312-valve, 60-air cooler, 40-gas-liquid separator, 41 / 42 / 43-pipeline, 50-reforming oil hydrogenation reactor, 51-pipeline. DETAILED DESCRIPTION

[0031] The method of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1 As shown, the device for producing a foaming agent raw material from a pentane fraction provided by the present invention comprises: a depentanizer 10, which is used to fractionate the reformed distillate oil hydrogenation product into a pentane fraction and a C6+ fraction; the depentanizer 10 comprises a feed pipeline 11 for feeding the reformed oil hydrogenation product oil to the depentanizer, a bottom removal device 13 for removing the C6+ fraction, and a top removal device 12 for removing the top product pentane fraction; A pentane hydrogenation reactor 30, in which the pentane fraction is contacted with hydrogen to perform a hydrogenation reaction; the pentane hydrogenation reactor 30 includes a hydrogenation catalyst bed; the inlet of the pentane hydrogenation reactor is connected to the tower top removal device (i.e., the tower top gas phase pipeline) 12 through the first heat exchanger 20; the outlet of the hydrogenation reactor is connected to the gas-liquid separator 40 through a pipeline after passing through the first heat exchanger 20 and the air cooler 60; a valve 312 is provided on the pipeline; a first heat exchanger 20 in which the pentane fraction and optional make-up hydrogen are heat exchanged with the effluent of the pentane hydrogenation reactor 30; The gas-liquid separator 40 separates the hydrogenation reaction effluent into gas and C4 / C5 liquid products after cooling; the liquid outlet of the gas-liquid separator 40 is connected to the top liquid phase reflux inlet 17 of the depentanizer 10 and the feed inlet of the C4 / C5 fractionator, respectively.

[0033] Preferably, the depentanizer 10 is further provided with a tower top gas reflux port 16 at a position higher than the liquid phase reflux port 15, and the outlet of the pentane hydrogenation reactor is also connected to the tower top gas reflux port 16 through a pipeline 31 after passing through the first heat exchanger 20. A valve 311 is provided on the pipeline for controlling the flow rate of gas reflux.

[0034] The device further comprises a C4 / C5 fractionation tower (not shown in the figure), in which the C4 / C5 liquid phase fraction is fractionated into C4 and C5 fractions.

[0035] Furthermore, the device also includes a reformed oil hydrogenation reactor 50, in which the reformed oil fraction and hydrogen undergo a hydrogenation refining reaction; the outlet of the reformed fraction oil hydrogenation reactor 50 is connected to the feed inlet of the depentanizer.

[0036] Combination Figure 1 The method for producing a blowing agent raw material from a pentane fraction of the present invention comprises the following contents: The pentane hydrogenation unit is put into operation, and the reformed oil enters the liquid phase hydrogenation reactor 50 through the pipeline 51 and the heat exchanger. The hydrogenation product (including the residual hydrogen from the reaction) enters the depentanizer 10 through the pipeline 11 for fractionation. The top pentane fraction (including hydrogen) enters the pentane hydrogenation reactor 30 through the top removal device 12 and the first heat exchanger 20. At the initial start-up, the valve 312 is closed and the valve 311 is slowly opened to allow all the pentane oil to return to the depentanizer 10 for reheating. The heated material reaches the operating conditions required for the reaction. , re-enter the pentane hydrogenation reactor 10 through the top pipeline of the depentanizer tower for reaction, and generate hydrogenation reaction heat for heat exchange of pentane feed fraction. At this time, slowly open valve 312, gradually close valve 311 partially or completely, and the qualified pentane generated oil passes through the cooler 60 to reduce the temperature, and then enters the gas-liquid separator 40. The gas phase product light hydrocarbons are discharged from the device through the top pipeline 41 of the gas-liquid separator. After the liquid phase product enters the subsequent C4 / C5 fractionation tower through pipeline 42, the bottom pentane fraction is directly used as the raw material for producing foaming agent. The pentane hydrogenation unit enters the normal production process. This flexible process avoids the problem of unqualified pentane products caused by substandard operating conditions in the initial stage of the device or during production.

[0037] During normal operation, the pentane feed conditions can be made to meet the needs of the reaction by flexibly adjusting the valve positions of valves 311 and 312 according to the conditions required for the reaction and changes in the properties of the pentane raw materials. At the same time, the problem of unqualified pentane products entering the downstream foaming agent production equipment in the initial stage of start-up and during normal production is solved, thereby avoiding the impact on the normal production of the foaming agent equipment.

[0038] When the method of the present invention is used for a reforming device using a clay refining process, the operation method is basically the same, and additional hydrogen needs to be supplied. However, since the required hydrogen is very small, it can be introduced from a suitable position inside the reforming device. When the hydrogenation device is started, the reforming oil can be first treated by the clay refining device and then introduced into the depentanizer, and the top material of the depentanizer is introduced into the hydrogenation reactor. First, all the materials at the outlet of the pentane hydrogenation reactor are introduced into the depentanizer for heat exchange, so that the temperature of the top pentane fraction is raised to the operating conditions required for the hydrogenation reaction, so that the hydrogenation reactor and the hydrogenation catalyst quickly reach the optimal state required for the reaction, and the problem of the properties of the pentane hydrogenation product failing to meet the indicators when the device is started will not be caused.

[0039] The pentane generated oil treated by the method of the present invention can achieve the following properties: the bromine index of the refined oil is less than 100 mgBr / 100g, and other properties meet the requirements for being a raw material for a foaming agent.

[0040] The advantages of the present invention are: simple process flow, easy operation and low investment. For the existing reforming unit of the oil refining enterprise, it is only necessary to add a hydrogenation depentanizer reactor and corresponding pipelines and valves between the top of the depentanizer tower and the cooler of the reforming unit, and it is not necessary to build a new set of hydrogenation units separately, which can greatly reduce investment and operating costs. The process flow of the method of the present invention is simple, the operating conditions are relatively mild, the feasibility is strong, and no additional hydrogen supply is required. If the existing process method is adopted, a new hydrogenation unit and supporting equipment need to be built, and the investment and operating costs are both high. At the same time, a return circulation pipeline from the bottom of the pentane hydrogenation reactor to the depentanizer tower is added. In the initial stage of operation and during normal production, the valve positions of valves 311 and valves 312 can be flexibly adjusted according to the conditions required for the reaction and the property changes of the pentane raw materials, so that the pentane feed conditions meet the needs of the reaction, and at the same time, the problem of unqualified pentane products entering the downstream foaming agent production unit in the initial stage of operation and during normal production is solved, thereby avoiding the impact on the normal production of the foaming agent unit.

[0041] The following examples will further illustrate the present invention.

[0042] The catalyst used in the experiment is a hydroprocessing catalyst for industrial applications, which is the FHDA-10 hydrogenation catalyst developed and produced by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. Its physical and chemical properties are shown in Table 1. Example 1

[0043] use Figure 1 The reforming oil passes through the liquid phase hydrogenation reactor and enters the depentanizer together with the residual hydrogen from the reaction. The pentane raw material 1 and hydrogen are obtained at the top of the tower and enter the pentane hydrogenation reactor. The method described in the present invention is used for hydrogenation treatment. When the operation is started, the pentane generated oil is first introduced into the depentanizer for heat exchange. After the material at the top of the depentanizer meets the reaction operating conditions, it is introduced into the pentane hydrogenation reactor. After 3 hours, it is switched to the normal operation process (pentane material enters the pentane hydrogenation reactor, and part of the pentane generated oil may no longer return to the depentanizer). The main operating conditions of the depentanizer are: the top temperature is 106°C, the bottom temperature is 215°C, and the operating pressure is 1.1MPa. The reflux inlet of the C5 fraction hydrogenation product is 3 plates higher than the reflux inlet of the C4 / C5 liquid phase product. The reflux ratio is 1:3. The properties of the pentane feedstock oil and the product properties are listed in Table 2.

[0044] As can be seen from Table 2, the use of this process technology can reduce the bromine index of the depentanizer top material to below 100 mgBr / 100 g, and the product quality remains stable throughout the entire start-up process. Example 2

[0045] The process modification of using reforming oil for bleaching clay refining is the method described in this application. After being refined by the bleaching clay tower, the reforming oil enters the depentanizer, and after the top pentane fraction raw material and the supplementary hydrogen are mixed, it enters the pentane hydrogenation reactor. The method described in the present invention is used to start the hydrogenation unit. When starting up, the pentane generated oil is first introduced into the depentanizer for heating. After the top material of the depentanizer meets the reaction operating conditions, it is introduced into the pentane hydrogenation reactor. After 5 hours, it is switched to the normal operation process (pentane material enters the pentane hydrogenation reactor, and part of the pentane generated oil may no longer return to the depentanizer). The main operating conditions of the depentanizer are: top temperature of 112°C, bottom temperature of 218°C, and operating pressure of 1.15MPa. The reflux inlet of the C5 fraction hydrogenation product is 4 plates higher than the reflux inlet of the C4 / C5 liquid phase product. The reflux ratio is 1:4. The properties of pentane feedstock oil and product properties are listed in Table 3.

[0046] As can be seen from Table 3, the use of this process technology can reduce the bromine index of the reforming oil to below 100 mgBr / 100g, and the product quality remains stable throughout the entire start-up process. Example 3

[0047] use Figure 1 The reforming oil passes through the liquid phase hydrogenation reactor and enters the depentanizer together with the residual hydrogen from the reaction. The pentane raw material 3 and hydrogen are obtained at the top of the tower and enter the pentane hydrogenation reactor. The method described in the present invention is used for hydrogenation treatment. When the operation is started, the pentane generated oil is first introduced into the depentanizer for heat exchange. After the material at the top of the depentanizer meets the reaction operating conditions, it is introduced into the pentane hydrogenation reactor. After 4 hours, it is switched to the normal operation process (pentane material enters the pentane hydrogenation reactor, and part of the pentane generated oil may no longer return to the depentanizer). The main operating conditions of the depentanizer are: the top temperature is 109°C, the bottom temperature is 221°C, and the operating pressure is 1.22MPa. The reflux inlet of the C5 fraction hydrogenation product is 3 plates higher than the reflux inlet of the C4 / C5 liquid phase product. The reflux ratio is 1:4. The properties of the pentane feedstock oil and the product properties are listed in Table 4.

[0048] As can be seen from Table 4, the use of this process technology can reduce the bromine index of the depentanizer top material to below 100 mgBr / 100 g, and the product quality remains stable throughout the entire start-up process.

[0049] Table 1 Physical and chemical properties of catalysts

[0050] Table 2 Properties of feedstock oil and test results of Example 1

[0051] Table 3 Properties of feedstock oil and test results of Example 2

[0052] Table 4: Properties of feedstock oil and test results of Example 3

Claims

1. A device for producing foaming agent raw materials from pentane fraction of a catalytic reforming device, characterized in that: The device comprises: A depentanizer, which is used to fractionate the reformed oil product into a C4 / C5 fraction and a C6+ (i.e., C6 and above) fraction; the depentanizer comprises a feed pipeline for feeding the reformed oil hydrogenation product to the depentanizer, a bottom take-off device for removing the C6+ fraction, and a top take-off device for removing the top product pentane fraction; A pentane hydrogenation reactor, in which the pentane fraction is contacted with hydrogen to carry out a hydrogenation reaction; the hydrogenation reactor comprises a hydrogenation catalyst bed; the inlet of the hydrogenation reactor is connected to the tower top removal device via a first heat exchanger; the outlet of the hydrogenation reactor is connected to the gas-liquid separator through a pipeline after passing through the first heat exchanger and an air cooler; a first heat exchanger in which the pentane fraction is heat exchanged with a hydrogenation reactor effluent; A gas-liquid separator, in which the hydrogenation reaction effluent after cooling is separated into gas and liquid products; the liquid outlet of the gas-liquid separator is respectively connected to the top liquid phase reflux inlet of the depentanizer and the feed inlet of the C4 / C5 fractionator.

2. The device according to claim 1, characterized in that The depentanizer is provided with a tower top gas reflux port at a position higher than the liquid phase reflux port, and the outlet of the pentane hydrogenation reactor is connected with the tower top gas reflux port through a pipeline after passing through the first heat exchanger.

3. The device according to claim 2, characterized in that The pipeline is provided with a valve for controlling the flow rate of the gas reflux at the top of the tower.

4. The device according to claim 1, characterized in that The device also includes a C4 / C5 fractionation tower, in which the C4 / C5 fraction obtained from the gas-liquid separator is fractionated into C4 and C5 fractions.

5. The device according to claim 1, characterized in that The device also includes a reformed oil hydrogenation reactor, which is used for hydrogenating the reformed oil fraction; the outlet of the reformed oil hydrogenation reactor is connected to the feed inlet of the depentanizer.

6. The device according to claim 1, characterized in that After the outlet of the pentane hydrogenation reactor passes through the first heat exchanger, a valve is provided on the connecting pipeline with the air cooler to control the flow of the material entering the gas-liquid separator through the air cooler.

7. A method for producing a foaming agent raw material from a pentane fraction of a catalytic reforming device, characterized in that: The following steps are involved: (1) The reformed oil product enters the depentanizer, and the pentane fraction is obtained at the top of the tower and the C6+ fraction is obtained at the bottom of the tower; (2) providing a pentane hydrogenation reactor; the pentane fraction obtained in step (1) is mixed with optional supplemental hydrogen, and after heat exchange with the pentane fraction hydrogenation product in a first heat exchanger, enters the pentane fraction hydrogenation reactor and passes through a hydrogenation catalyst bed under hydrogenation conditions; (3) The hydrogenation product of the pentane fraction after cooling in the first heat exchanger is divided into two paths, one of which is returned to the upper tray of the depentanizer through the gas phase reflux port; (4) Another path of the pentane fraction hydrogenation product after cooling in the first heat exchanger enters the gas-liquid separator after further cooling to obtain a gas phase product and a C4 / C5 liquid phase product; (5) The C4 / C5 liquid product obtained in step (4) is divided into two paths, one path enters the downstream C4 / C5 fractionation tower, and the other path is used as liquid reflux and returns to the upper part of the depentanizer through the liquid reflux port.

8. The method according to claim 7, characterized in that The reformed oil product in step (1) is a hydrogenation product obtained by hydrogenating the reformed oil fraction, which contains unreacted hydrogen or dissolved hydrogen; or, the reformed oil hydrogenation product is a product obtained by refining the reformed oil fraction with kaolin.

9. The method according to claim 7, characterized in that: The position where the hydrogenated product of the pentane fraction obtained in step (3) is returned to the depentanizer, i.e., the gas phase reflux port, is higher than the position where the C4 / C5 liquid phase product obtained in step (4) is returned to the depentanizer, i.e., the liquid phase reflux port.

10. The method according to claim 9, characterized in that The position where the pentane fraction hydrogenation product returns to the depentanizer is 1 to 5 trays higher than the position where the C4 / C5 liquid phase product returns to the depentanizer.

11. The method according to claim 7, characterized in that The operating conditions of the depentanizer in step (1) include: a tower top temperature of 80-120° C., a tower bottom temperature of 180-225° C., and an operating pressure of 0.8-1.2 MPa.

12. The method according to claim 7, characterized in that The hydrogenation conditions in step (2) include: a reaction pressure of 0.5 MPa to 6.0 MPa, preferably 0.8 MPa to 2.0 MPa; a reaction temperature of 80°C to 200°C, preferably 100°C to 160°C; a liquid phase volume space velocity of 1.0 h-1 to 15.0 h-1, preferably 4.0 h-1 -1 ~10.0 h -1 The volume ratio of hydrogen to oil is 0~20:1, preferably 3~8:

1.

13. The method according to claim 7, characterized in that The hydrorefining catalyst uses alumina as a carrier and Pt and / or Pd as active components. The content of the active components in the catalyst is 0.1% to 1.5% by weight.

14. The method according to claim 7, characterized in that The volume ratio of the C5 fraction hydrogenation product returned to the upper part of the depentanizer in step (3) to the C5 fraction hydrogenation product entering the gas-liquid separator in step (4) is 1:4-1:

1.

15. The method according to claim 7, characterized in that The mass fraction of the liquid reflux material in the C4 / C5 liquid product obtained in step (4) is 10-50% of the total C4 / C5 liquid product.

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