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

Abstract

The invention discloses a device and a method for producing a foaming agent from pentane fraction by using a catalytic reforming device. A reformate raw material enters a depentanizer, C4 / C5 fractions are obtained at the top of the depentanizer, and pentane-containing fractions are extracted from a side line at the upper part of the depentanizer; the obtained pentane-containing fraction enters a pentane hydrogenation reactor for a hydrogenation reaction, and a hydrogenation product is mixed with low-temperature naphtha at the top of a separation tower of the reforming pre-hydrogenation unit and then returns to the upper part of the depentanizer; the obtained C4 / C5 fraction is subjected to gas-liquid separation to obtain a liquid product, the liquid product is divided into two streams, one stream is mixed with optional reforming pre-hydrogenation unit separation tower top low-temperature naphtha and then enters a C4 / C5 fractionating tower, and the other stream returns to a reflux inlet II of the depentanizer. According to the method disclosed by the invention, the pentane fraction hydrogenation process flow is greatly simplified, and the device investment and the operation cost are reduced.

Description

Technical Field

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

[0002] Reforming oil can be directly used as a blending component of motor gasoline, or it can be extracted from aromatics to produce benzene, toluene and xylene, while hydrogen is produced as a by-product. However, the utilization of low molecular weight hydrocarbons that cannot be converted into aromatics, mainly C5-fractions, has not received widespread attention. In my country, cyclopentane replaces Freon as a foaming agent in the polyurethane industry and can completely replace imported products; cyclopentane is also an important basic chemical raw material, such as the production of chlorocyclopentane and cyclopentadiene. 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; hydrocarbon aerosols, foaming agents, solvent oils, etc. further developed from saturated hydrocarbons are widely used in cosmetics, fragrances, rubber, plastics, greases 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. 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 production 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 in 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.

[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 from pentane fraction of a catalytic reforming device. By deeply coupling the pentane hydrotreating device with the reforming device, not only can the various indicators of the pentane oil fraction after hydrogenation meet the requirements for producing foaming agent, but the investment, energy consumption, operating costs and land occupation are greatly reduced compared with the existing devices, and at the same time, the problem that the temperature of the material at the top of the depentanizer does not meet the reaction requirements of the hydrogenation unit 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, the device for producing foaming agent raw materials from pentane fraction of the catalytic reforming device includes: A depentanizer for fractionating the reformate product into a C4 / C5 fraction and a heavy fraction (i.e., a C6+ fraction); the depentanizer comprises a feed line for feeding the reformate feedstock to the depentanizer, a bottom take-off device for removing the heavy fraction, a side line take-off device for removing a pentane-containing fraction from the top of the depentanizer, and a top take-off device for removing a top product C4 / C5 fraction; A pentane hydrogenation reactor, in which the pentane-containing fraction and hydrogen are subjected to a hydrogenation reaction in the presence of a hydrogenation catalyst; the inlet of the pentane hydrogenation reactor is connected to the extraction side line, and the outlet pipeline of the pentane hydrogenation reactor is connected to the reflux port I at the top of the depentanizer after merging with the naphtha pipeline at the top of the reforming pre-hydrogenation unit separation tower; The outlet of the hydrogenation reactor is connected to the gas-liquid separator through a pipeline via the heat exchanger I and the cooler; preferably, a valve is provided on the pipeline; A gas-liquid separator, in which the cooled depentanizer top product is separated into gas and liquid products; the liquid outlet of the gas-liquid separator is respectively connected to the reflux port II of the C4 / C5 fractionating tower and the feed port of the C4 / C5 fractionating tower; A C4 / C5 fractionator, in which the liquid product obtained by the gas-liquid separator is separated into liquefied gas and pentane oil; the C4 / C5 fractionator comprises a removal device for removing liquefied gas, a bottom removal device for removing pentane oil products, and an optional feed pipeline for feeding low-temperature naphtha from the top of the separation tower of the partial reforming pre-hydrogenation unit to the C4 / C5 fractionator; Among them, the opening positions of the reflux port I, the side line extraction port and the reflux port II are successively lowered.

[0010] Furthermore, a valve is provided on the reforming unit pre-hydrogenated low-temperature naphtha pipeline for controlling the flow of the reforming unit pre-hydrogenated low-temperature naphtha entering the depentanizer.

[0011] Furthermore, the device also includes a reformed oil liquid phase hydrogenation reactor, and the outlet of the reformed oil hydrogenation reactor is connected to the feed inlet of the depentanizer.

[0012] Furthermore, the opening position of the reflux port I is 1-7 plates higher than the side line extraction port, preferably 2-5 plates higher; the opening position of the reflux port II is 1-6 plates lower than the side line extraction port, preferably 2-4 plates lower.

[0013] In the present invention, since the discharge temperature of the gas phase product at the top of the depentanizer cannot meet the requirements of the hydrogenation reaction, the pentane hydrogenation unit needs to be set at a suitable position of the side line of the depentanizer to ensure that the temperature of the pentane-containing material extracted from the side line can directly meet the requirements of the hydrogenation reaction conditions. At the same time, the side line hydrogenation unit is added to the upper part of the depentanizer, and the process flow of extracting from the lower part and returning to the upper part is adopted, which can effectively avoid the problem of repeated hydrogenation of the pentane-containing material extracted from the side line.

[0014] In the present invention, since the temperature of the material at the top of the depentanizer cannot meet the requirements of the hydrogenation reaction, it needs to be increased by 10 to 25°C to meet the reaction requirements. Therefore, the pentane hydrogenation unit is set at a suitable position of the side line of the depentanizer to ensure that the temperature of the extracted material can directly meet the requirements of the hydrogenation reaction conditions. Preferably, the pentane hydrogenation reactor is arranged at the upper side line position of the depentanizer of the reforming unit, generally at the 3rd to 30th tower plates, preferably at the 5th to 20th tower plates. The temperature of the side line extracted material (containing hydrogen) of the depentanizer can directly reach the required operating conditions, and the pentane hydrogenation reactor directly enters the normal production stage after the introduction of the material, and no unqualified products are produced.

[0015] 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.

[0016] Specifically, the method for producing a foaming agent raw material comprises the following steps: (1) The reformed oil feedstock enters the depentanizer, and the C4 / C5 fraction is obtained at the top of the tower. The pentane-containing fraction is extracted from the upper side line, and the C6+ fraction is obtained at the bottom of the tower; (2) the pentane-containing fraction obtained in step (1) is directly fed into a pentane hydrogenation reactor and subjected to a hydrogenation reaction with optional hydrogen in the presence of a hydrogenation catalyst; (3) The product of the pentane hydrogenation reactor is mixed with the low-temperature naphtha at the top of the reforming pre-hydrogenation unit separation tower and then returned to the top of the depentanizer through reflux port I; (4) The C4 / C5 fraction obtained in step (1) is cooled and then enters a gas-liquid separator for separation to obtain light hydrocarbons and liquid products; (5) The liquid product obtained in step (4) is divided into two streams, one of which is mixed with the low-temperature naphtha at the top of the optional reforming pre-hydrogenation unit separation tower and then enters the C4 / C5 fractionation tower, and the other stream returns to the reflux port II of the depentanizer.

[0017] Furthermore, the temperature of the pentane-containing fraction extracted from the side line in step (1) is generally 95-135°C, preferably 105-130°C.

[0018] Furthermore, in step (2), the conditions for the hydrogenation reaction 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 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 1.0h -1 ~15.0h -1 , preferably 4.0 h -1 ~10.0 h -1 The volume ratio of hydrogen (i.e., additional supplementary hydrogen) to oil is 0 to 20:1 (since the pentane-containing fraction extracted from the side line 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.

[0019] In the present invention, during the pentane hydrogenation reaction, the material is in a gas phase circulation mode. Since the temperature distribution of the depentanizer is gradually increased from the bottom of the tower to the top of the tower, and the hydrogenation reaction is an exothermic reaction, the temperature of the material after the reaction will be higher than the feed temperature, so the process of extracting the material from the bottom of the depentanizer and returning the top must be realized, and the temperature of the material after the reaction must be reduced. By mixing the small part of the reforming prehydrogenation unit fractionation tower top naphtha entering the C4 / C5 fractionator with the hydrogenation reaction product to reduce the temperature of the material after the reaction, it is made to meet the temperature requirement of returning to the top of the depentanizer, and the normal operation of the depentanizer is not adversely affected. In addition, since the side line extracts out the pentane-containing material containing a small amount of C6 or more aromatic components, in order to avoid the loss of high-value aromatics due to the occurrence of aromatic saturation, it is preferred to load high-selectivity precious metals or high-nickel hydrogenation catalysts in the pentane hydrogenation reactor so that the aromatic content of the material after hydrogenation is not reduced substantially.

[0020] The hydrogenation catalyst described in step (2) can 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 selectivity and can carry out a selective olefin hydrogenation reaction at a relatively low temperature, but has a very weak performance in the hydrogenation of aromatics. In the present invention, it is preferred to use a hydrorefining catalyst with a medium noble metal as an active component, such as the FHDO-18 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. Both catalyst active metals are distributed on the outer surface 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 100mgBr / 100g, meeting the index requirements for the production of pentane foaming agent.

[0021] Furthermore, in step (3), after the pentane hydrogenation product is mixed with the low-temperature naphtha at the top of the reforming pre-hydrogenation unit fractionation tower, the temperature of the reflux stream obtained is generally 80-120° C., preferably 90-115° C. Wherein, the ratio of the low-temperature naphtha at the top of the reforming pre-hydrogenation unit fractionation tower to the pentane hydrogenation product is generally 20-70m%, preferably 30-60m%.

[0022] Further, the pentane hydrogenation reactor can adopt the 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 is not cooled and separated, and is mixed with a small amount of reforming pre-hydrogenation unit fractionation tower top naphtha entering the C4 / C5 fractionation tower, reducing the temperature of the material after the reaction, so that it meets the temperature requirement of returning to the upper part of the depentanizer, and has no adverse effect on the normal operation of the depentanizer. The pentane hydrogenation reactor can also adopt the lower feeding 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 set at the bottom of the pentane hydrogenation reactor, and the pentane generated oil is all conveyed to the reflux inlet at the corresponding position of the depentanizer side line 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, part or all of the top material of the depentanizer is returned to the top of the depentanizer.

[0023] Furthermore, the gas-liquid separator in step (4) adopts conventional operating conditions in the art.

[0024] Furthermore, in step (5), the mass ratio of the liquid product obtained in step (4) entering the C4 / C5 fractionation tower and returning to the reflux port II of the depentanizer is generally 1:6-1:1, preferably 1:4-1:2.

[0025] Furthermore, the ratio of the naphtha from the top of the reforming pre-hydrogenation unit separation tower entering the depentanizer through the reflux port I to the flow entering the C4 / C5 fractionator is generally 10-60m%, preferably 20-50m%.

[0026] Furthermore, the temperature of the low-temperature naphtha at the top of the separation tower of the reforming pre-hydrogenation unit is generally 20-70°C, preferably 25-55°C.

[0027] Furthermore, the depentane tower in step (1) adopts conventional operating conditions in the art. The operating conditions generally include: tower top temperature of 80-100°C, tower bottom temperature of 185-225°C, and operating pressure of 0.8-1.0 MPa.

[0028] The method for producing foaming agent from pentane fraction of catalytic reforming device of the present invention comprises the following contents: before the reforming oil enters the depentanizer, liquid phase hydrogenation treatment is carried out to remove most of the trace olefins therein. The reforming oil after hydrogenation and the remaining hydrogen enter the depentanizer for fractionation, a hydrogenation reaction unit is added in the middle and upper part of the depentanizer, the side line material of the depentanizer (containing hydrogen) directly enters the hydrogenation reactor for reaction, the reaction effluent is mixed with the low-temperature naphtha of the top part of the fractionation tower of the pre-hydrogenation unit of the reforming device, and then the upper reflux port I of the material extracted from the side line of the depentanizer is returned to the tower for re-fractionation, the top material of the depentanizer enters the product separator after cooling, the gas phase component after separation is discharged from the device, the liquid phase hydrogenation product enters the subsequent C4 / C5 fractionation tower, and the C5 fraction separated at the bottom of the tower can be directly used to produce pentane foaming agent.

[0029] Compared with the prior art, the present invention has the following beneficial effects: 1. After the reforming oil is hydrotreated, 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. For example, as a raw material for producing foaming agents, further processing is required. Generally speaking, the use of hydrogenation treatment can make the refined product meet the requirements, but the required reaction conditions must be met in order to make the properties of the pentane generated oil meet the requirements for producing foaming agent raw materials. However, the temperature at the top of the depentanizer tower of the reforming unit is significantly low, and the reaction materials need to be increased by at least 10~25℃. By setting the pentane hydrogenation unit at a suitable position on the side line of the depentanizer tower, it is ensured that the temperature of the side line extracted material can directly meet the requirements of the hydrogenation reaction conditions, which completely solves the problem of unqualified properties of pentane generated oil due to substandard reaction conditions, and has the advantages of short start-up time and no unqualified products leaving the unit.

[0030] 2. In the present invention, the additional pentane hydrogenation unit is cleverly arranged at a suitable position of the side line of the depentanizer, so that the material temperature directly meets the reaction condition requirements, and the process flow of extracting the side line material from the lower part and returning the upper part is adopted, which avoids the problem of increased loss of aromatics due to repeated hydrogenation of the pentane-containing material, and has no adverse effect on the normal operation of the depentanizer. The design of the pipeline and corresponding valves for returning the pentane hydrogenation generated oil to the depentanizer is combined with the actual characteristics of the device, that is, the pressure at the top of the depentanizer is relatively suitable, and the temperature is high (the reaction temperature is too high, which is not conducive to the olefin saturation reaction, and is prone to cause oversaturation of aromatics, affecting product quality). By mixing the material after the pentane hydrogenation reaction with a small part of low-temperature naphtha, the temperature of the reflux material is reduced, so that it can be smoothly returned from the top of the depentanizer.

[0031] 3. 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 in the upper part of the depentanizer as raw hydrogen, and extracts the pentane raw material from the side line of the depentanizer and enters the hydrogenation reactor from the upper part of the reactor, which greatly simplifies the process flow and reduces the investment cost. When the pentane hydrogenation device is started, since the material temperature at the corresponding position of the side line of the depentanizer can meet the requirements of the hydrogenation reaction, it is selected to directly introduce the side line extracted material into the pentane hydrogenation reactor, so that the hydrogenation reactor and the hydrogenation catalyst quickly reach the optimal state required for the reaction, and will not cause the problem that the properties of the hydrogenation reaction product do not meet the indicators when the device is started or the device is operating normally. This method makes the present process method have better flexibility, and the normal operation of the subsequent foaming agent production device will not be affected by the present process method. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the process of the device of the present invention.

[0033] Among them, the digital marks correspond to: 10-depentanizer, 11-feed pipeline, 12-top removal device, 13-bottom removal device, 14 / 15-reflux port, 16-side line extraction port, 20-pentane oil hydrogenation reactor, 21-extraction side line, 22-pipeline, 23-supplementary hydrogen pipeline, 30-cooler, 40-gas-liquid separator, 41 / 42-pipeline, 421-valve, 50-C4 / C5 fractionator, 51-gas phase pipeline, 52-liquid phase pipeline, 71 / 72-pipeline, 721-valve, 60-reforming oil hydrogenation reactor, 61-pipeline. DETAILED DESCRIPTION

[0034] The method of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Combination Figure 1 The device for producing a foaming agent raw material of the present invention comprises: A depentanizer 10 is used to fractionate the reformed oil feedstock into a C4 / C5 fraction and a heavy (C6+) fraction; the depentanizer 10 comprises a feed pipeline 11 for feeding the reformed oil feedstock to the depentanizer, a bottom take-off device 13 for removing the heavy (C6+) fraction, a side line 21 for extracting a pentane-containing fraction from the upper part of the depentanizer, and a top take-off device 12 for removing the top product C4 / C5 fraction; A pentane hydrogenation reactor 20, in which the pentane-containing fraction and hydrogen are subjected to a hydrogenation reaction in the presence of a hydrogenation catalyst; the inlet of the pentane hydrogenation reactor 20 is connected to the extraction side line, and the pentane hydrogenation reactor product outlet pipeline 22 is connected to the naphtha pipeline 72 at the top of the reforming pre-hydrogenation unit separation tower, and then connected to the reflux port Ⅰ14 at the top of the depentanizer; A gas-liquid separator 40, in which the depentanizer top product after cooling is separated into gas and liquid products; the liquid outlet of the gas-liquid separator is connected to the reflux port II15 of the C4 / C5 fractionating tower and the feed port of the C4 / C5 fractionating tower 50 through pipelines 42 and 43 respectively; A C4 / C5 fractionator 50, in which the liquid product obtained by the gas-liquid separator is separated into liquefied gas and pentane oil, which are removed through pipelines 51 and 52 respectively; the C4 / C5 fractionator 50 comprises a removal device 41 for removing liquefied gas, a tower bottom removal device 52 for removing pentane oil products, and an optional pipeline 71 for feeding low-temperature naphtha from the top of the separation tower of the partial reforming pre-hydrogenation unit to the C4 / C5 fractionator; The positions of the reflux port I 14, the side-line extraction port 16 and the reflux port II 15 are successively lower. Preferably, the reflux port I 14 is 1-7 trays higher than the side-line extraction port 16, preferably 2-5 trays higher; the reflux port II 15 is 1-6 trays lower than the side-line extraction port 16, preferably 2-4 trays lower.

[0036] Furthermore, the device also includes a reformed oil liquid phase hydrogenation reactor 60, and the outlet of the reformed oil hydrogenation reactor is connected to the feed inlet of the depentanizer.

[0037] In the present invention, since the discharge temperature of the gas phase product at the top of the depentanizer cannot meet the requirements of the hydrogenation reaction, the pentane hydrogenation unit needs to be set at a suitable position of the side line of the depentanizer to ensure that the temperature of the pentane-containing material extracted from the side line can directly meet the requirements of the hydrogenation reaction conditions. At the same time, the side line hydrogenation unit is added to the upper part of the depentanizer, and the process flow of extracting from the lower part and returning to the upper part is adopted, which can effectively avoid the problem of repeated hydrogenation of the pentane-containing material extracted from the side line.

[0038] In the present invention, since the temperature of the material at the top of the depentanizer cannot meet the requirements of the hydrogenation reaction, it needs to be increased by 10 to 25°C to meet the reaction requirements. Therefore, the pentane hydrogenation unit is set at a suitable position of the side line of the depentanizer to ensure that the temperature of the extracted material can directly meet the requirements of the hydrogenation reaction conditions. Preferably, the pentane hydrogenation reactor is arranged at the upper side line position of the depentanizer of the reforming unit, generally at the 3rd to 30th tower plates, preferably at the 5th to 20th tower plates. The temperature of the side line extracted material (containing hydrogen) of the depentanizer can directly reach the required operating conditions, and the pentane hydrogenation reactor directly enters the normal production stage after the introduction of the material, and no unqualified products are produced.

[0039] For a reforming device using the method of the present invention, such as Figure 1 As shown: the reforming oil product enters the depentanizer 10 through the pipeline 11 (containing the residual hydrogen from the reaction) for fractionation, the side line pentane fraction (containing hydrogen) is extracted through the side line 21, and enters the pentane hydrogenation reactor 20 with the optional supplementary hydrogen through the supplementary hydrogen pipeline 23, the hydrogenation reaction product is mixed with a small amount of naphtha from the top of the reforming pre-hydrogenation unit separation tower flowing through the pipeline 72 to cool down, and then returns to the depentanizer 3 through the upper reflux port Ⅰ14 of the depentanizer for re-fractionation, the naphtha from the top of the reforming pre-hydrogenation unit separation tower and the pentane hydrogenation unit reaction product and the mixed amount are controlled by the valve position, and the reflux port Ⅱ15 can effectively control the temperature of the return to the depentanizer 10, the refined pentane fraction is removed from the top of the tower by the device 12, passes through the cooler 30 and the gas-liquid separator 40 to the downstream C4 / C5 fractionation tower 50, and the separated refined pentane oil is removed through the pipeline 52 and can be directly used for the production of pentane foaming agent. Entering the normal production process, this flexible process avoids the problem of substandard pentane products caused by substandard operating conditions at the top of the depentanizer.

[0040] During normal operation, the temperature of the reaction product 6 of the pentane hydrogenation reactor can meet the requirement of returning to the upper part of the depentanizer by flexibly adjusting the valve position of the valve 721 according to the conditions required for the reaction and the property changes of the pentane raw material, without affecting the stable operation of the depentanizer 10. The feed conditions can directly meet the needs of the reaction, and solve the problem of unqualified pentane products entering the downstream foaming agent production device in the initial stage of the start-up and during the normal production process, avoiding the impact on the normal production of the foaming agent device.

[0041] When the reforming device using the clay refining process adopts the method of the present invention, the operation method is basically the same, and the supplementary hydrogen needs to be supplied additionally, but 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 reformed oil can be first treated by the clay refining device and then introduced into the depentanizer. The tower side line material of the depentanizer is directly introduced into the hydrogenation reactor to remove trace olefins therein. After the reaction product is mixed with a small part of the low-temperature reforming pre-hydrogenation unit fractionation tower top naphtha, it returns to the top of the depentanizer for re-fractionation. The depentanizer top fraction passes through a cooler and a gas-liquid separator and enters the C4 / C5 fractionation tower. The tower bottom material is directly used to produce pentane foaming agent. The feed temperature of the pentane hydrogenation reactor directly meets 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 will not cause the problem that the properties of the pentane hydrogenation product do not meet the index when the device is started.

[0042] 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.

[0043] 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 reactor and corresponding pipelines and valves to the side line of the depentanizer 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 high. At the same time, adding a mixing pipeline and valve of low-temperature naphtha and reaction products at the top of the reforming pre-hydrogenation unit fractionation tower can effectively reduce the temperature of the reaction product, so that it meets the requirement of returning to the depentanizer from the upper part of the feed position of the pentane hydrogenation reactor, avoiding the problem of repeated hydrogenation of the pentane fraction, and having no adverse effect on the normal production operation of the depentanizer. In addition, a precious metal or high-nickel hydrogenation catalyst with high selectivity is loaded in the pentane hydrogenation reactor, and the active metals of the catalyst are distributed on the outer surface of the catalyst, so that the aromatic content of the hydrogenated material is basically not reduced.

[0044] The following examples will further illustrate the present invention.

[0045] The catalyst used in the experiment is an industrially applied hydroprocessing catalyst, which is the FHDO-18 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

[0046] According to the reforming device of the present application, the reforming oil passes through the liquid phase hydrogenation reactor and enters the depentanizer together with the residual hydrogen from the reaction. The side pentane feed 1 and hydrogen enter the pentane hydrogenation reactor. The reaction conditions are: reaction pressure 0.95 MPa, volume space velocity 7.0 h -1 , reactor inlet temperature 108°C. The main operating conditions of the depentanizer are: tower top temperature 90°C, tower bottom temperature 207°C, and operating pressure 0.89MPa. , 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 method described in the present invention is used for hydrogenation treatment to ensure that the refined product directly meets the quality requirements of the foaming agent. The properties of the pentane feed oil and the product properties are listed in Table 2.

[0047] As can be seen from Table 2, the use of this process technology can reduce the bromine index of the material after hydrogenation in the side line of the depentanizer to below 100 mgBr / 100 g, and no unqualified products are generated during the entire start-up process. Example 2

[0048] The process modification of using reforming oil to refine with clay is the method described in this application. The reforming oil is refined by the clay tower and then enters the depentanizer. The side pentane feedstock 2 of the tower is mixed with the supplementary hydrogen and then enters the pentane hydrogenation reactor. The reaction conditions are: reaction pressure 0.95MPa, volume space velocity 6.0h -1 , reactor inlet temperature 110°C, supplementary hydrogen to oil ratio 6. The main operating conditions of the depentanizer: tower top temperature 93°C, tower bottom temperature 211°C, operating pressure 0.91MPa. The reflux inlet of the C5 fraction hydrogenation product is 3 trays higher than the reflux inlet of the C4 / C5 liquid phase product. Reflux ratio 1:4. The method described in the present invention is used for hydrogenation treatment to ensure that the refined product directly meets the quality requirements of the foaming agent. The properties of the pentane feed oil and the product properties are listed in Table 3.

[0049] As can be seen from Table 3, the use of this process technology can reduce the bromine index of the material after hydrogenation in the side line of the depentanizer to below 100 mgBr / 100 g, and no unqualified products are generated during the entire start-up process. Example 3

[0050] According to the reforming device of the present application, the reforming oil passes through the liquid phase hydrogenation reactor and enters the depentanizer together with the residual hydrogen from the reaction. The side pentane feed 3 and hydrogen enter the pentane hydrogenation reactor. The reaction conditions are: reaction pressure 0.98 MPa, volume space velocity 6.7 h -1 , reactor inlet temperature 115°C. The main operating conditions of the depentanizer are: tower top temperature 94°C, tower bottom temperature 215°C, and operating pressure 0.94MPa. The reflux inlet of the C5 fraction hydrogenation product is 4 trays higher than the reflux inlet of the C4 / C5 liquid phase product. The reflux ratio is 1:3. The method described in the present invention is used for hydrogenation treatment to ensure that the refined product directly meets the quality requirements of the foaming agent. The properties of the pentane feed oil and the product properties are listed in Table 4.

[0051] As can be seen from Table 4, the use of this process technology can reduce the bromine index of the material after side hydrogenation in the depentanizer to below 100 mgBr / 100 g, and no unqualified products are generated during the entire start-up process.

[0052] Table 1 Physical and chemical properties of catalysts catalyst FHDO-18 Metal composition Pt-Pd Physical properties Pore ​​volume, mL / g ≮0.48 <![CDATA[Specific surface area, m 2 / g]]> ≮160 Compressive strength, N / cm ≮90 shape Cylindrical bar Table 2 Properties of feedstock oil and test results of Example 1

[0053] Table 3 Properties of feedstock oil and test results of Example 2

[0054] 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: include: A depentanizer for fractionating the reformate product into a C4 / C5 fraction and a C6+ heavy fraction; the depentanizer comprises a feed line for feeding the reformate feedstock to the depentanizer, a bottom take-off device for removing the C6+ heavy fraction, a side line take-off device for removing a pentane-containing fraction from the top of the depentanizer, and a top take-off device for removing a top product C4 / C5 fraction; A pentane hydrogenation reactor, in which the pentane-containing fraction and hydrogen are subjected to a hydrogenation reaction in the presence of a hydrogenation catalyst; the inlet of the pentane hydrogenation reactor is connected to the extraction side line, and the outlet pipeline of the pentane hydrogenation reactor is connected to the reflux port I at the top of the depentanizer after merging with the naphtha pipeline at the top of the reforming pre-hydrogenation unit separation tower; The outlet of the hydrogenation reactor is connected to the gas-liquid separator through a pipeline via the heat exchanger I and the cooler; preferably, a valve is provided on the pipeline; A gas-liquid separator, in which the cooled depentanizer top product is separated into gas and liquid products; the liquid outlet of the gas-liquid separator is respectively connected to the reflux port II of the C4 / C5 fractionating tower and the feed port of the C4 / C5 fractionating tower; A C4 / C5 distillation tower, in which the liquid product obtained from the gas-liquid separator is separated into liquefied gas and pentane oil; the C4 / C5 distillation tower includes a removal device for removing liquefied gas, a bottom removal device for removing pentane oil products, and an optional feed pipeline for feeding low-temperature naphtha from the top of the separation tower of the partial reforming pre-hydrogenation unit to the C4 / C5 distillation tower.

2. The device according to claim 1, characterized in that The opening positions of the reflux port I, the side line extraction port and the reflux port II are successively lowered.

3. The device according to claim 1, characterized in that A valve is provided on the reforming unit pre-hydrogenated low-temperature naphtha pipeline for controlling the flow of the reforming unit pre-hydrogenated low-temperature naphtha entering the depentanizer.

4. The device according to claim 1, characterized in that The device also includes a reformed oil liquid phase hydrogenation reactor, and the outlet of the reformed oil hydrogenation reactor is connected to the feed inlet of the depentanizer.

5. The device according to claim 2, characterized in that The opening position of reflux port I is 1-7 plates higher than the side line extraction port, preferably 2-5 plates higher; the opening position of reflux port II is 1-6 plates lower than the side line extraction port, preferably 2-4 plates lower.

6. The device according to claim 1, characterized in that The pentane hydrogenation reactor is arranged at the upper side line position of the depentanizer of the reforming unit, preferably at the 3rd to 30th tray, and most preferably at the 5th to 20th tray.

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 feedstock enters the depentanizer, and the C4 / C5 fraction is obtained at the top of the tower. The pentane-containing fraction is extracted from the upper side line, and the C6+ heavy fraction is obtained at the bottom of the tower; (2) the pentane-containing fraction obtained in step (1) is directly fed into a pentane hydrogenation reactor and subjected to a hydrogenation reaction with optional hydrogen in the presence of a hydrogenation catalyst; (3) The product of the pentane hydrogenation reactor is mixed with the low-temperature naphtha at the top of the reforming pre-hydrogenation unit separation tower and then returned to the top of the depentanizer through reflux port I; (4) The C4 / C5 fraction obtained in step (1) is cooled and then enters a gas-liquid separator for separation to obtain light hydrocarbons and liquid products; (5) The liquid product obtained in step (4) is divided into two streams, one of which is mixed with the low-temperature naphtha at the top of the optional reforming pre-hydrogenation unit separation tower and then enters the C4 / C5 fractionation tower, and the other stream returns to the reflux port II of the depentanizer.

8. The method according to claim 7, characterized in that The temperature of the pentane-containing fraction extracted from the side line in step (1) is generally 95-135°C, preferably 105-130°C.

9. The method according to claim 7, characterized in that: The conditions of the hydrogenation reaction 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 ~15.0h -1 , preferably 4.0 h -1 ~10.0 h -1 ; The volume ratio of hydrogen to oil is 0~20:1, preferably 3~8:

1.

10. The method according to claim 7, characterized in that In step (3), after the pentane hydrogenation product is mixed with the low-temperature naphtha at the top of the reforming pre-hydrogenation unit fractionation tower, the temperature of the obtained reflux stream is 80-120°C, preferably 90-115°C.

11. The method according to claim 10, characterized in that in, The mixing ratio of low-temperature naphtha at the top of the fractionation tower of the pre-hydrogenation unit of the reforming unit and the material after pentane hydrogenation is 20~70m%.

12. The method according to claim 7, characterized in that In step (5), the mass ratio of the liquid product obtained in step (4) entering the C4 / C5 fractionation tower and returning to the reflux port II of the depentanizer is 1:6-1:1, preferably 1:4-1:

2.

13. The method according to claim 7, characterized in that The ratio of the naphtha from the top of the reforming pre-hydrogenation unit separation tower entering the depentanizer through the reflux port I to the logistics entering the C4 / C5 fractionator is 10-60m%, preferably 20-50m%.

14. The method according to claim 7, characterized in that The temperature of the low-temperature naphtha at the top of the reforming pre-hydrogenation unit separation tower is 20-70°C, preferably 25-55°C.

15. The method according to claim 7, characterized in that The operating conditions of the depentane tower in step (1) include: tower top temperature of 80-100°C, tower bottom temperature of 185-225°C, and operating pressure of 0.8-1.0 MPa.

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