Apparatus and process for the production of blowing agent feedstocks from pentane fractions

Abstract

The application discloses a device and method for producing foaming agent raw material from pentane fraction. The method comprises the following steps: liquid phase hydrogenation treatment is performed on reforming generated oil; the hydrogenated reforming generated oil and residual hydrogen enter a de-pentane column for fractionation, a hydrogenation reaction unit is additionally arranged before a reflux tank at the top of the de-pentane column, the material at the top of the de-pentane column is mixed with part of pentane fraction at the bottom of a subsequent C4 / C5 fractionation column, and then enters the hydrogenation unit for hydrogenation; liquid phase hydrogenation products obtained by separating reaction effluent enter the subsequent C4 / C5 fractionation column, and C5 fraction obtained at the bottom is directly used as raw material for producing pentane foaming agent. The method greatly simplifies the hydrogenation process flow of the pentane fraction, and reduces device investment and operation cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrogenation technology, and relates to a method for producing foaming agent raw material from a pentane fraction, in particular, a pentane fraction processing unit of a catalytic reforming device is combined in the catalytic reforming device, and the method is particularly suitable for the catalytic reforming device which needs to produce foaming agent raw material. BACKGROUND

[0002] Catalytic reforming is one of the important processes in petroleum refining. It is a process in which naphtha is converted into reformate rich in aromatics under the action of noble metal catalyst at a relatively high temperature, low pressure and in the presence of hydrogen. The reformate can be directly used as a blending component of motor gasoline, and can also be used to extract benzene, toluene and xylene through aromatics extraction, while by-product hydrogen is produced. The low molecular hydrocarbons, mainly C5 fraction, which cannot be converted into aromatics, have not been widely used. The light naphtha of the reforming device is a very valuable petroleum resource, and its components are relatively light, and are basically saturated alkanes, in which C3 and C4 components account for about 40% to 50%, C5 components account for about 50% to 60%, and the remaining is a trace amount of C5+ components. Saturated C5 hydrocarbons, including n-pentane, isopentane and cyclopentane, have a wide range of applications in the industrial field. Isopentane can be used as a solvent for the catalyst for synthesizing 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 isopentanol and isoprene. N-pentane can be used as a desorbent for the molecular sieve dewaxing process, and a mixture of n-pentane and isopentane in different proportions can meet the requirements of different foaming degrees, and can completely replace imported products. The mixture of n-pentane and isopentane can be used as a catalyst for polyethylene.

[0003] At present, the light naphtha is often used as a gasoline blending component or a raw material for an aromatization device. However, since the light naphtha is rich in C4-C6 alkanes, directly blending the light naphtha into gasoline will reduce the octane number of the gasoline and increase the vapor pressure of the gasoline. If the light naphtha is subjected to aromatization conversion, a new device needs to be built, and investment costs are increased. Since the light naphtha is rich in C5 alkanes, the part of the raw material can be used to produce high-purity pentane oil, i.e. pentane foaming agent. The foaming agent is a substance that promotes the generation of foam to form a closed-cell or interconnected-cell structure material, and is also called a foaming agent or a blowing agent. Traditional fluorochlorohydrocarbon foaming agents are gradually abandoned due to environmental pollution problems, and the pentane foaming agent has the advantages of small greenhouse gas potential (GWP), small toxicity, safety and environmental protection, and can be used as a fluorochlorohydrocarbon substitute to meet various environmental protection requirements. From the physical and chemical properties of the foaming agent, the reforming device is very suitable for producing high-purity pentane foaming agent.

[0004] In recent years, China's oil refining industry has rapidly expanded its capacity through a combination of expansion and new construction. However, the market for fuel oil is becoming saturated, and the rapid development of new energy vehicles is expected to reduce demand for gasoline. As a result, some enterprises are having difficulty producing gasoline. In addition, the use of light naphtha as a blending component for gasoline can reduce the octane rating and increase the saturated vapor pressure of gasoline, which is more pronounced in the summer. In this context, many domestic refining and chemical companies have optimized the use of light naphtha by adjusting their process flow, adjusting their processing scheme, and building new devices. For example, a 2.6 million ton / year naphtha hydrogenation unit in a certain PetroChina company and a 300,000 ton / year naphtha hydrogenation unit in a certain Sinopec company use light naphtha to produce pentane blowing agent, achieving good economic and social benefits.

[0005] CN111362773A discloses a device and process for preparing pentane blowing agent from reforming overhead naphtha. The method connects a feed buffer tank to a de-isopentane column, and the top of the de-isopentane column is connected to the bottom of a common rectification column. The de-isopentane column has a partition tower inside, and the upper side line of the de-isopentane column is connected to an isopentane product tank, and the middle side line of the de-isopentane column is connected to a blowing agent tank. The bottom of the common rectification column is connected to the top of the de-isopentane column through a common rectification column feed pump. The present invention omits the reaction section and the subsequent fractionation section, and has obvious energy-saving effect. In addition, the process uses a partition rectification process technology to complete the operation that requires two fractionation columns, saving equipment investment. However, compared with the method of the present invention, the method processes light naphtha obtained from a reforming pre-hydrogenation device, while the method of the present invention processes light naphtha from the top of the de-pentane column of a reforming device, and the raw materials and properties are completely different.

[0006] CN104557392B discloses a method for producing pentane. Ether post-C5 is used as raw material, and hydrogenation and removal of residual olefins are used to produce pentane products with qualified pentane index. Ether post-C5 and hydrogen are mixed and then passed through a fixed bed catalyst bed for hydrogenation reaction, and the catalyst is a Ni / diatomite catalyst. The hydrogenation product is passed through a strong acid cation exchange resin fixed bed at a temperature of 10-40°C to remove residual unsaturated hydrocarbons. The raw material processed by this method is completely different from the method of the present invention, and the catalyst used and the reaction mechanism also have significant differences. In addition, a new independent hydrogenation device needs to be built, and the investment and operating costs are also relatively high. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a device and method for producing foaming agent raw material from pentane fraction, which optimally combines pentane hydrotreating device and reforming device, so as to not only meet the requirements of the indexes of pentane generated oil after hydrogenation for producing foaming agent, but also greatly reduce the investment, energy consumption and operating cost compared with the existing device, and at the same time solve the problem of unqualified product quality caused by the failure of operation condition to meet the requirements at the initial stage and during the production of the hydrogenation unit.

[0008] According to the first aspect of the present application, the present application provides a device for producing foaming agent raw material from pentane fraction.

[0009] Specifically, the device for producing foaming agent raw material from pentane fraction comprises:

[0010] a de-pentanizer for fractionating the reforming fraction oil hydrogenation product into C4 / C5 fraction and C6 + fraction; the de-pentanizer comprises a feed line for feeding the reforming fraction oil hydrogenation product into the de-pentanizer, a bottom removal device for removing the C6+ fraction, and a top removal device for removing the top product C4 / C5 fraction;

[0011] a pentane hydrogenation reactor, in which the C4 / C5 fraction is subjected to hydrogenation reaction with hydrogen in the presence of a hydrogenation catalyst; the pentane hydrogenation reactor inlet is connected to the top removal device through a pipeline via a heat exchanger I; the hydrogenation reactor outlet is connected to a gas-liquid separator through a pipeline after the heat exchanger I and a cooler; preferably, a valve is arranged on the pipeline;

[0012] a heat exchanger I, in which the pentane fraction is subjected to heat exchange with the hydrogenation reactor effluent;

[0013] a gas-liquid separator, in which the cooled hydrogenation reaction effluent is separated into gaseous and liquid products; the liquid outlet of the gas-liquid separator is connected to the top liquid reflux port of the C4 / C5 fractionating column and the feed port of the C4 / C5 fractionating column, respectively;

[0014] a C4 / C5 fractionating column, in which the pentane hydrogenation product is separated into liquefied gas and pentane oil; the C4 / C5 fractionating column comprises a gas phase removal device for removing the liquefied gas, a bottom removal device for removing the pentane oil product, and a feed line for feeding part of the pentane oil product into the heat exchanger I.

[0015] Further, the de-pentanizer is further provided with a top gas reflux port at a position higher than the liquid reflux port, and the pentane hydrogenation reactor outlet is further connected to the top gas reflux port through a pipeline after the heat exchanger I. Further, a valve is arranged on the pipeline for flow control of the top gas reflux material.

[0016] Further, the apparatus further comprises a reforming distillate hydrogenation reactor, and an outlet of the reforming distillate hydrogenation reactor is communicated with a feed inlet of the de-pentanizer.

[0017] According to a second aspect of the present application, the present application provides a method for producing a foaming agent raw material from a pentane fraction.

[0018] The method for producing a foaming agent raw material from a pentane fraction comprises the following steps:

[0019] (1) The reforming oil hydrogenation product enters the de-pentanizer, and a C4 / C5 fraction is obtained at the top of the tower, and a C6 + (or above C6) fraction is obtained at the bottom of the tower;

[0020] (2) The C4 / C5 fraction obtained in step (1) is mixed with the part of the liquid phase product circulating at the bottom of the C4 / C5 fraction column and optional additional hydrogen, and after heat exchange with the C5 fraction hydrogenation product, enters the pentane (C5 fraction) hydrogenation reactor, and hydrogenation reaction is carried out in the presence of a hydrogenation catalyst;

[0021] (3) The C4 / C5 fraction hydrogenation product cooled by the heat exchanger I is divided into two routes, one of which returns to the gas phase reflux port of the upper tray of the de-pentanizer;

[0022] (4) The other route of the C4 / C5 fraction hydrogenation product cooled by the heat exchanger I enters the gas-liquid separator after further cooling, and a gas phase product and a C4 / C5 liquid phase product are obtained;

[0023] (5) The C4 / C5 liquid phase product obtained in step (4) is divided into two streams, one of which enters the C4 / C5 fraction column, and the other of which returns to the liquid phase reflux port of the upper part of the de-pentanizer as a liquid phase reflux;

[0024] (6) The bottom product obtained from the C4 / C5 fraction column, one of which is removed as a foaming agent raw material, and the other of which enters the heat exchanger I.

[0025] Further, the position (i.e. the position of the gas phase reflux port) of the C5 fraction hydrogenation product obtained in step (3) returned to the de-pentanizer is higher than the position (i.e. the position of the liquid phase reflux port) of the C4 / C5 liquid phase product returned to the de-pentanizer in step (5). Preferably, the position of the gas phase reflux port is 1-5 trays higher than the position of the liquid phase reflux port. By making the position of the C5 fraction hydrogenation product returned to the de-pentanizer higher than the position of the C4 / C5 liquid phase product obtained in step (4) returned to the de-pentanizer, a part of the C5 fraction hydrogenation product passing through the first heat exchanger can re-enter the de-pentanizer, be further heated in the de-pentanizer, and after being removed through the top, it is equivalent to increasing the inlet temperature of the C4 / C5 hydrogenation reactor, which helps to quickly obtain the minimum temperature of the hydrogenation reaction at the beginning of the start-up, and after normal operation, by adjusting the opening degree of the valve, the amount of C5 fraction hydrogenation product returned can be appropriately reduced.

[0026] Furthermore, the depentane degasser in step (1) operates under conventional conditions in the art. These conditions generally include: a top temperature of 80-120°C, a bottom temperature of 180-225°C, and an operating pressure of 0.8-1.2 MPa.

[0027] Furthermore, the hydrogenation conditions described in step (2) include: a reaction pressure generally of 0.5 MPa to 6.0 MPa, preferably 0.8 MPa to 2.0 MPa. The reaction pressure is usually determined based on the pressure at the top of the depentanizer and generally does not need to be adjusted, but can be adjusted appropriately as needed. The reaction temperature is generally 80℃ to 200℃, preferably 100℃ to 160℃. The liquid phase (or gas phase, or liquid phase) volume hourly space velocity is 1.0 h⁻¹. -1 ~15. 0h -1 Preferably 4.0 h -1 ~10.0 h -1 The hydrogen-to-oil volume ratio is 0~20:1 (since the depentanizer overhead material contains dissolved hydrogen, the additional hydrogen can be 0), preferably 3~8:1. In this invention, the hydrogen-to-oil volume ratio can be significantly reduced compared to existing conventional methods.

[0028] The hydrogenation reactor in step (2) uses a hydrogenation catalyst, and the hydrogenation treatment reaction effluent directly enters a C4 / C5 column for fractionation treatment; the main innovation is that a hydrogenation product return de-pentane column pipeline and a corresponding valve are arranged in the pentane hydrogenation unit, and a C4 / C5 fractionation column bottom pentane fraction return pipeline and a corresponding valve are arranged; at the initial stage of starting the device, the pentane hydrogenation product to the subsequent cooler pipeline valve is closed, and the pentane hydrogenation product return de-pentane column valve is opened, and the pentane hydrogenation reactor uses a gas phase circulation mode, and the material is returned to the de-pentane column to obtain more heat sources, so that when the reaction material enters the pentane hydrogenation reactor, the feed condition can meet the requirements of the hydrogenation reaction condition as soon as possible. When the reaction condition meets the requirements, the pentane fraction hydrogenation product is heat-exchanged with the feed, and then the pentane product return de-pentane column valve is gradually partially or completely closed, and the product into the gas-liquid separator valve is slowly opened, so that the problem of unqualified pentane product at the initial stage is solved. When the reaction condition meets the requirements, the de-pentane column top material temperature is significantly improved, and a large amount of heat is released after passing through the reactor, and the hydrogenation product is heat-exchanged with the feed, so that the pentane hydrogenation unit operating condition rapidly meets the reaction requirements, and then the pentane product return de-pentane column valve is gradually partially or completely closed, and the product into the cooler and gas-liquid separator valve is slowly opened, and when the device enters normal production, the C4 / C5 fractionation column bottom pentane fraction return valve is properly opened, so that a small amount of high-temperature pentane material is returned to the pentane hydrogenation reactor inlet and mixed with the de-pentane column top material, so that the temperature of the reaction material is further improved, and then the amount of pentane hydrogenation reactor return de-pentane column material is gradually reduced, and the de-pentane column top temperature is properly reduced, so as to avoid affecting the de-pentane column fractionation effect. The technical scheme effectively solves the problem of unqualified pentane product at the initial stage and during normal production, and maximally avoids the influence of the de-pentane column top temperature increase on the fractionation effect.

[0029] In the present application, a pipeline connecting the pentane hydrogenation reactor outlet and the de-pentane column is preferably arranged, and at the start of the hydrogenation reactor, the hydrogenation reactor outlet material is first returned to the de-pentane column for heat exchange and temperature rise, and the material uses a gas phase total reflux mode, and after 5 minutes to 24 hours, preferably 1 to 10 hours, when the de-pentane column top material (containing hydrogen) reaction temperature reaches the required operating condition and the hydrogenation product temperature is significantly increased, the return de-pentane column valve is gradually partially or completely closed, and the pentane refined oil gradually enters the downstream cooler and separator, and the pentane hydrogenation unit enters the normal production stage. When the pentane hydrogenation unit is in normal production, the C4 / C5 fractionation column bottom pentane fraction return valve is properly opened, a small amount of high-temperature pentane material is returned to the pentane hydrogenation reactor inlet and mixed with the de-pentane column top reaction material, and the return amount is generally 5% to 70%, preferably 10% to 40%.

[0030] In the method, the hydrogenation reactor is arranged between the top outlet of the depentanizer and the cooler, the material (containing hydrogen) discharged from the top of the depentanizer is mixed with part of the pentane fraction returned from the bottom of the subsequent C4 / C5 fractionating tower, and after passing through the heat exchanger, the mixture enters the pentane hydrogenation reactor. The 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 after being cooled and separated, the refined oil enters the C4 / C5 separation unit, and the C5 fraction can be directly used to produce a foaming agent raw material. The 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 hydrogenation reactor adopts a gas phase reaction state, that is, under the reaction condition, most of the pentane fraction is in a gas phase state. The bottom of the pentane hydrogenation reactor is provided with a material conveying device, and part or all of the pentane oil generated is conveyed to the inlet of the corresponding position at the top of the depentanizer through the material conveying device. The bottom of the C4 / C5 fractionating tower is provided with a material conveying device, and part of the high-temperature pentane fraction is conveyed to the inlet of the corresponding position before the pentane hydrogenation reactor through the material conveying device. The depentanizer is generally provided with a tower bottom reboiler to provide heat for the depentanizer. When the pentane fraction hydrogenation reactor is started, part or all of the material at the top of the depentanizer is returned to the top of the depentanizer.

[0031] In the method, the pentane fraction is the top fraction of the depentanizer of the reforming device generated oil.

[0032] Further, 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.

[0033] Further, the mass fraction of the material as the liquid phase reflux in the C4 / C5 liquid phase product obtained in step (5) in the total C4 / C5 liquid phase product is 10-50%.

[0034] Further, the hydrofining catalyst used in the present application can be a commercial hydrofining catalyst, such as a hydrofining catalyst with noble metal or reduced nickel as active component. Such catalysts have high hydrogenation activity and can perform hydrogenation reaction at relatively low temperature. Preferably, a hydrofining catalyst with intermediate noble metal as active component is used, such as the FHDA-10 catalyst developed and produced by SINOPEC (Dalian) Petroleum Chemical Research Institute Co., Ltd. The noble metal hydrofining catalyst generally uses alumina as carrier and Pt and / or Pd as active component, and the content of the active component in the catalyst is not less than 0.1% by weight, generally 0.1%-1.5%. For the hydrofining catalyst with reduced nickel as active component, generally alumina or modified alumina is used as carrier and nickel oxide is used as active component (15%-70% of the weight of the catalyst, preferably 25%-45%). Before use, the catalyst is reduced and activated to convert the nickel oxide into reduced state, so as to improve the hydrogenation activity of the catalyst. For the pentane fraction of reforming generated oil, the use of the hydrofining catalyst can make the bromine index of the pentane fraction of reforming generated oil less than 100 mgBr / 100g, meeting the index requirement of the production of blowing agent raw material.

[0035] After the reforming generated oil is hydrotreated, the bromine index of the separated pentane fraction is still high, generally several thousand or even tens of thousands. For a reforming device with high severity, the bromine index of the pentane fraction is even higher. If used as raw material for the production of blowing agent, the pentane fraction must be further processed. Generally, the use of hydrotreatment method can make the refined product meet the requirement, but the required reaction condition must be met to make the properties of the pentane generated oil meet the requirement of the production of blowing agent raw material. The reaction temperature at the top of the de-pentanizer of the reforming device is obviously low, and the reaction material needs to be increased by at least 10-25℃. By setting the pipeline and the corresponding valve for returning the pentane generated oil to the de-pentanizer and setting the pipeline and the corresponding valve for returning the pentane fraction at the bottom of the C4 / C5 fractionating tower, the problem of unqualified properties of the pentane generated oil caused by the failure to meet the reaction condition during the initial start-up and normal production is completely solved, and the process has the advantages of short initial start-up time, no unqualified product out of the device, and little influence on the separation effect of the de-pentanizer. In the present application, the pipeline and the corresponding valve for returning the pentane generated oil to the de-pentanizer are designed, and the pipeline and the corresponding valve for returning the pentane fraction at the bottom of the C4 / C5 fractionating tower are set, and the actual characteristics of the device are combined, i.e. the pressure at the top of the de-pentanizer is relatively appropriate, but the temperature is low. By returning the pentane generated oil gas phase material partially or completely to the de-pentanizer, the material can fully obtain the required heat, meeting the requirement of the reaction condition, and solving the problem of unqualified properties of the pentane refined oil during the initial start-up and normal production. The process has little influence on the fractionation effect of the de-pentanizer. The present application has the advantages of ingenious design, simple process flow, easy implementation, low maintenance cost, and effective avoidance of the problem of unqualified product quality, and has little influence on the normal operation of the original equipment.

[0036] This invention, while ensuring system pressure balance and meeting the pressure requirements for the hydrogenation reaction, fully utilizes the surplus hydrogen from the top of the depentane column as feedstock hydrogen. This hydrogen, along with the pentane feedstock, enters the hydrogenation reactor from the top of the reactor, significantly simplifying the process and reducing investment costs. Simultaneously, during startup of the hydrogenation unit, the low temperature at the top of the column fails to meet the hydrogenation reaction requirements. Therefore, all the material emanating from the pentane hydrogenation reactor is first introduced into the depentane column, raising the temperature of the pentane fraction at the top of the column to the operating conditions required for the hydrogenation reaction. This allows the hydrogenation reactor and hydrogenation catalyst to quickly reach the optimal state for the reaction, preventing the hydrogenation reaction product properties from failing to meet specifications during startup. Once the hydrogenation unit is operating normally, the pentane fraction return valve at the bottom of the C4 / C5 fractionation column is moderately opened, allowing a small amount of high-temperature pentane material to return to the inlet of the pentane hydrogenation reactor and mix with the material from the top of the depentane column, further raising the temperature of the reactants. At this point, by gradually reducing the amount of material returning from the pentane hydrogenation reactor to the depentane column, the top temperature of the depentane column is moderately lowered, avoiding any negative impact on the fractionation efficiency of the depentane column. This method makes the process more flexible and will not affect the normal operation of the subsequent foaming agent production equipment. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the process of the device of the present invention.

[0038] In the diagram, the numbers correspond to: 10-Depentane tower, 11-Feed line, 12-Top removal device, 13-Bottom removal device, 14-Supplemental hydrogen line, 15-Gas reflux port, 16-Liquid reflux port, 20-C4 / C5 hydrogenation reactor, 21-Line, 30-Heat exchanger I, 31 / 32-Valves, 40-Air cooler, 50-Gas-liquid separator, 51 / 52 / 53-Line, 60-C4 / C5 fractionation tower, 61 / 62 / 63-Line, 70-Reformed oil hydrogenation reactor, 71-Line. Implementation

[0039] The method of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 As shown, the apparatus for producing foaming agent feedstock from pentane fraction of the present invention includes: a depentanizer 10, which is used to fractionate the hydrogenation product of reformate oil into C4 / C5 fractions and C6 fractions. + The depentane tower 10 includes a feed line 11 for feeding the reformate oil hydrogenation product into the depentane tower, a bottom removal device 13 for removing the C6+ fraction, and a top removal device 12 for removing the top product C4 / C5 fraction.

[0041] a pentane hydrogenation reactor 20 in which the C4 / C5 fraction is hydrogenated in the presence of a hydrogenation catalyst; the pentane hydrogenation reactor 20 is connected by a line to the overhead removal device via a heat exchanger I; the hydrogenation reactor outlet is connected by a line to a gas-liquid separator 50 via a heat exchanger I 30 and a cooler 40; preferably, valves 31 and 32 are provided in the line;

[0042] a heat exchanger I 30 in which the C4 / C5 fraction is heat exchanged with the hydrogenation reactor effluent;

[0043] a gas-liquid separator 50 in which the partially hydrogenated reactor effluent after cooling is separated into a gaseous and a liquid product; the liquid outlet of the gas-liquid separator is connected by a line 52 to the liquid reflux inlet 15 of the C4 / C5 fractionation column and by a line 53 to the feed inlet of the C4 / C5 fractionation column;

[0044] a C4 / C5 fractionation column 60 in which the liquid product from the pentane gas-liquid separator is fractionated into a liquefied gas and a pentane oil; the C4 / C5 fractionation column 60 comprises a gaseous phase removal device 61 for removing the liquefied gas fraction, a liquid phase removal device 62 for removing the pentane oil product and a feed line 63 for feeding part of the pentane oil product from the column bottom to the heat exchanger I.

[0045] Further, the depentanizer 10 is provided with a gas reflux inlet 15 above the liquid reflux inlet, and the pentane hydrogenation reactor outlet is connected by a line to the gas reflux inlet 15 via the heat exchanger I. Further, valves are provided in the line for flow control of the gas reflux.

[0046] Further, the device comprises a reformate hydrogenation reactor 70, the outlet of which is connected to the feed inlet of the depentanizer, and the reformate hydrogenation reactor feed inlet is connected to a feed line 71.

[0047] In combination Figure 1The method for producing foaming agent raw material from pentane fraction of the present application comprises: starting up the pentane hydrogenation device, the reforming generated oil enters the reforming generated oil hydrogenation reactor 70 through the heat exchanger, the hydrogenation product (containing residual hydrogen) enters the de-pentanizer 10 for fractionation, the C4 / C5 fraction (containing hydrogen) at the top of the column enters the pentane hydrogenation reactor 20 through the heat exchanger, at the initial stage of starting up, the valve 32 is closed and the valve 31 is slowly opened, so that the pentane generated oil returns to the de-pentanizer 10 for re-heating, the heated material reaches the operating conditions required for the reaction, and is removed from the de-pentanizer top through the pipeline and re-enters the pentane hydrogenation reactor 20 for reaction, at the same time, the hydrogenation reaction heat is used for heat exchange of the pentane feed fraction, at this time, the valve 32 is slowly opened and the valve 31 is gradually partially or completely closed, the qualified pentane generated oil enters the gas-liquid separator 50 after being cooled by the cooler 40, the gaseous product is removed from the device through the top pipeline 51 of the gas-liquid separator, and the liquid product enters the C4 / C5 fraction column 60 through the pipeline 53, part of the pentane fraction at the bottom of the column is removed from the device through the pipeline 62 and directly used as the raw material for producing the foaming agent, and the other part of the high-temperature pentane fraction at the bottom of the column is returned to the pentane hydrogenation reactor through the pipeline 63 and mixed with the material to be hydrogenated at the top of the de-pentanizer 10, so as to further increase the temperature of the reaction material. The pentane hydrogenation unit enters the normal production process, and this flexible process avoids the problem of unqualified pentane product caused by the fact that the operating conditions do not meet the requirements at the initial stage of starting up or during the production process, and can maximize the influence on the fractionation effect of the de-pentanizer.

[0048] During normal operation, according to the required conditions of the reaction and the property changes of the pentane raw material, the valve position of the valve 31, the valve 32 and the valve (not shown in the figure) provided on the pipeline 63 is flexibly adjusted and controlled, so that the pentane feed conditions meet the requirements of the reaction, at the same time, the problem of unqualified pentane product entering the downstream foaming agent production device at the initial stage of starting up or during the production process is solved, and the influence on the normal production of the foaming agent device is avoided.

[0049] When the method of the present application is used in a reforming unit using a clay refining process, the operation method is basically the same, and the supplemental hydrogen needs to be supplied additionally, but since the hydrogen required is very little, it can be introduced from a suitable position inside the reforming unit. When the hydrogenation unit is started, the reformate can be first treated by the clay refining unit, and then introduced into the de-pentanizer column, the overhead material of the de-pentanizer column is introduced into the hydrogenation reactor, the outlet material of the pentane hydrogenation reactor is all introduced into the de-pentanizer column for heat exchange, the temperature of the pentane fraction at the top is raised to the operating condition required for hydrogenation reaction, the hydrogenation reactor and the hydrogenation catalyst quickly reach the optimum state required for the reaction, and the problem that the properties of the pentane hydrogenation product cannot reach the index during the start-up of the unit is solved. After the pentane hydrogenation unit is normally operated, the pentane fraction return valve at the bottom of the C4 / C5 fractionating column is properly opened, a small amount of high-temperature pentane material is returned to the inlet of the pentane hydrogenation reactor, mixed with the overhead material of the de-pentanizer column, and the temperature of the material to be reacted is further raised, at this time, by gradually reducing the amount of material returned from the pentane hydrogenation reactor to the de-pentanizer column, the temperature at the top of the de-pentanizer column is properly reduced, and the negative influence on the fractionation effect of the de-pentanizer column is avoided.

[0050] The pentane reformate treated by the method of the present application can reach the following properties: the refined oil bromine index is less than 100 mgBr / 100g, and other properties meet the requirements of the raw material for foaming agent.

[0051] The present application has the advantages of simple process flow, simple operation, less investment and land occupation. For the existing catalytic reforming unit of a refinery, only a hydrogenation reactor and corresponding pipelines and valves need to be added between the de-pentanizer column and the cooler of the catalytic reforming unit, a separate hydrogenation unit does not need to be newly built, and the investment and operating cost can be greatly reduced. The process flow of the method of the present application is simple, the operating condition is relatively mild, the implementability is strong, the operation flexibility is strong, and no additional hydrogen supply is required. If the existing process method is used, a hydrogenation unit and supporting equipment need to be newly built, and the investment and operating cost are both high. The return circulation pipeline from the bottom of the pentane hydrogenation reactor to the de-pentanizer column is added, during the initial start-up and normal production process, the valve position of the valve 8, the valve 9 and the valve 14 can be flexibly adjusted according to the reaction required condition and the property change of the pentane raw material, so that the pentane feed condition meets the requirement of the reaction, and the problem that the unqualified pentane product enters the downstream foaming agent production device during the initial start-up and normal production process is solved, the influence on the normal production of the foaming agent device is avoided, and the influence on the fractionation effect of the de-pentanizer column is also avoided to the maximum extent.

[0052] The following examples will further illustrate the present application.

[0053] The catalyst used in the experiment is an industrial application hydrogenation treatment catalyst, which is the FHDA-10 hydrogenation catalyst developed and produced by SINOPEC (Dalian) Petroleum Chemical Research Institute Co., Ltd., and the physical and chemical property indexes are shown in Table 1. Example 1

[0054] The catalytic reforming unit according to the present application. The reforming oil after passing through the liquid phase hydrogenation reactor and the remaining hydrogen gas after reaction enter the de-pentanizer together, and the pentane raw material 1 and hydrogen gas at the top of the tower enter the pentane hydrogenation reactor, the reaction conditions are: reaction pressure 0.99 MPa, volume space velocity 8.0 h -1 , reactor inlet temperature 107℃. The hydrogenation unit is started up by using the method described in the present application. At the start-up, the pentane oil is first introduced into the de-pentanizer for heat exchange. After the material at the top of the de-pentanizer meets the reaction operating conditions, it is introduced into the pentane hydrogenation reactor. After 3 hours, the normal operating process is switched (the pentane material enters the pentane hydrogenation reactor, and the pentane oil is partially returned to the de-pentanizer). The pentane hydrogenation oil returns to the de-pentanizer at a ratio of 15%, and the pentane fraction at the bottom of the C4 / C5 fractionating tower returns to the pentane hydrogenation reactor at a ratio of 12%. The main operating conditions of the de-pentanizer are: tower top temperature 91℃, tower bottom temperature 197℃, and operating pressure 1.0 MPa. The C5 fraction hydrogenation product reflux inlet is 3 plates higher than the C4 / C5 liquid phase product reflux inlet, and the reflux ratio is 1:3. The properties of the pentane raw material and the product properties are listed in Table 2.

[0055] As can be seen from Table 2, using this process technology can reduce the bromine index of the material at the top of the de-pentanizer to below 100 mgBr / 100g, and the product quality also remains stable during the entire start-up process. Example 2

[0056] The process of using clay refining of reforming oil is modified to the method described in the present application. The reforming oil after passing through the clay tower enters the de-pentanizer, and the pentane raw material 2 and the supplemental hydrogen gas are mixed and then enter the pentane hydrogenation reactor, the reaction conditions are: reaction pressure 1.06 MPa, volume space velocity 7.0 h -1 , reactor inlet temperature 115℃. The hydrogenation unit is started up by using the method described in the present application. At the start-up, the pentane oil is first introduced into the de-pentanizer for heat exchange. After the material at the top of the de-pentanizer meets the reaction operating conditions, it is introduced into the pentane hydrogenation reactor. After 5 hours, the normal operating process is switched (the pentane material enters the pentane hydrogenation reactor, and the pentane oil is partially or not returned to the de-pentanizer). The pentane hydrogenation oil returns to the de-pentanizer at a ratio of 10%, and the pentane fraction at the bottom of the C4 / C5 fractionating tower returns to the pentane hydrogenation reactor at a ratio of 17%. The operating conditions of the de-pentanizer are: tower top temperature 90℃, tower bottom temperature 213℃, and operating pressure 1.07 MPa. The C5 fraction hydrogenation product reflux inlet is 3 plates higher than the C4 / C5 liquid phase product reflux inlet. The reflux ratio is 1:3. The properties of the pentane raw material and the product properties are listed in Table 3.

[0057] As shown in Table 3, the bromine index of the reforming product can be reduced to below 100 mgBr / 100g by using the process technology, and the product quality is stable during the whole start-up process. Example 3

[0058] The catalytic reforming unit according to the present application. After the reforming product passes through the liquid-phase hydrogenation reactor and enters the de-pentanizer together with the residual hydrogen, the pentane raw material 3 and hydrogen at the top of the tower enter the pentane hydrogenation reactor, and the reaction conditions are: reaction pressure 1.12 MPa, volume space velocity 6.3 h -1 The hydrogenation unit is started up by using the method according to the present application. During the start-up, the pentane product is first introduced into the de-pentanizer for heat exchange. After the material at the top of the de-pentanizer meets the reaction operating conditions, the pentane hydrogenation reactor is introduced. After 3 hours, the normal operating process is switched (the pentane material enters the pentane hydrogenation reactor, and the pentane product is partially returned to the de-pentanizer), and the pentane hydrogenation product is returned to the de-pentanizer at a ratio of 15%, and the pentane fraction at the bottom of the C4 / C5 fractionating tower is returned to the pentane hydrogenation reactor at a ratio of 14%. The main operating conditions of the de-pentanizer are: tower top temperature 89℃, tower bottom temperature 212℃, and operating pressure 1.12 MPa. The reflux inlet of the pentane hydrogenation product is higher than that of the C4 / C5 liquid-phase product by 3 tower plates. The reflux ratio is 1:3. The properties of the pentane raw material and the product properties are listed in Table 4.

[0059] As shown in Table 4, the bromine index of the material at the top of the de-pentanizer can be reduced to below 100 mgBr / 100g by using the process technology, and the product quality is stable during the whole start-up process.

[0060] Table 1 Physical and chemical property indexes of the catalyst

[0061] Catalyst No. FHDA-10 Metal composition Pt-Pd Physical properties Pore volume, mL / g ≮0.45 Specific surface area, m 2 / g]] ≮160 Pressure resistance, N / cm ≮90 Shape Cylindrical bar

[0062] Table 2 Properties of the raw material oil and test results of Example 1

[0063]

[0064] Table 3 Properties of the raw material oil and test results of Example 2

[0065]

[0066] Table 4 Properties of the raw material oil and test results of Example 3

[0067]

Claims

1. An apparatus for producing a blowing agent feedstock from a pentane fraction, characterized by include: A depentanizer is used to fractionate the hydrogenated product of reformate oil into C4 / C5 fractions and C6+ fractions; the depentanizer includes a feed line for feeding the hydrogenated product of reformate oil into the depentanizer, a bottom removal device for removing the C6+ fraction, and a top removal device for removing the top product C4 / C5 fraction; The depentane tower is also equipped with a top gas reflux port at a position higher than the liquid phase reflux port. The outlet of the pentane hydrogenation reactor is connected to the top gas reflux port through a pipeline after passing through heat exchanger I. A valve is installed on the pipeline between heat exchanger I and the top gas reflux port for controlling the flow rate of the top gas reflux stream. A pentane hydrogenation reactor is used in which C4 / C5 fractions react with hydrogen in the presence of a hydrogenation catalyst. The inlet of the pentane hydrogenation reactor is connected to the top removal device of the column via a pipeline through heat exchanger I. The outlet of the pentane hydrogenation reactor is connected to a gas-liquid separator via a pipeline after passing through heat exchanger I and a cooler. A valve is installed on the pipeline between heat exchanger I and the cooler. Heat exchanger I, in which the C4 / C5 fraction and the C4 / C5 fraction hydrogenation product exchange heat; A gas-liquid separator separates the cooled C4 / C5 fraction hydrogenation product into a gaseous product and a liquid product; the liquid outlet of the gas-liquid separator is connected to the liquid reflux port at the top of the depentanizer and the feed port of the C4 / C5 fractionation tower, respectively. A C4 / C5 fractionation column, wherein the liquid product is separated into liquefied petroleum gas (LPG) and pentane oil; the C4 / C5 fractionation column includes a gas phase removal device for removing LPG, a bottom removal device for removing pentane oil product, and a feed line for feeding a portion of the pentane oil product to heat exchanger I.

2. The apparatus according to claim 1, characterized in that, The apparatus also includes a reformate oil hydrogenation reactor, the outlet of which is connected to the feed inlet of the depentanizer.

3. A method for producing foaming agent raw materials from pentane fraction, characterized in that, The apparatus for producing foaming agent raw materials using pentane fraction as described in claim 1 or 2, the method comprising the following steps: (1) The hydrogenation product of reformed distillate enters the depentanizer, where C4 / C5 fraction is obtained at the top and C6+ fraction is obtained at the bottom. (2) The C4 / C5 fraction obtained in step (1) is mixed with a portion of the pentane oil recycled from the bottom of the C4 / C5 fractionation tower and optional supplementary hydrogen. After heat exchange with the hydrogenation product of the C4 / C5 fraction, it enters the pentane hydrogenation reactor and undergoes hydrogenation reaction in the presence of a hydrogenation catalyst. (3) The hydrogenation product of the C4 / C5 fraction after being cooled by heat exchanger I is divided into two streams, one of which returns to the gas reflux port at the top of the depentanizer; (4) The hydrogenation product of the C4 / C5 fraction after being cooled by heat exchanger I enters the gas-liquid separator after further cooling to obtain gaseous and liquid products; (5) The liquid product obtained in step (4) is divided into two streams, one of which enters the C4 / C5 fractionation tower, and the other is returned to the liquid reflux port at the top of the depentane tower as liquid phase reflux; (6) Of the bottom products obtained from the C4 / C5 fractionation column, one stream is removed as a foaming agent raw material, and the other stream enters heat exchanger I.

4. The method according to claim 3, characterized in that, The gas phase reflux port is 1-5 trays higher than the liquid phase reflux port.

5. The method according to claim 3, characterized in that, The operating conditions of the depentane tower include: top temperature 80~120℃, bottom temperature 180~225℃, and operating pressure 0.8~1.2MPa.

6. The method according to claim 3, characterized in that, The hydrogenation conditions of the pentane hydrogenation reactor include: the reaction pressure is 0.5 MPa-6.0 MPa, the reaction temperature is 80℃-200℃, the liquid phase volume space velocity is 1.0 h -1 ~15. 0h -1 , and the hydrogen-oil volume ratio is 0-20:

1.

7. The method according to claim 6, characterized in that, The hydrogenation conditions of the pentane hydrogenation reactor include: the reaction pressure is 0.8 MPa ~2.0 MPa, the reaction temperature is 100℃ ~160℃, the liquid phase volume space velocity is 4.0 h -1 ~10.0 h -1 , and the hydrogen-oil volume ratio is 3 ~8:

1.

8. The method according to claim 3, characterized in that, The volume ratio of the C4 / C5 fraction hydrogenation product returned to the top of the depentane tower in step (3) to the C4 / C5 fraction hydrogenation product entering the gas-liquid separator in step (4) is 1:4-1:

1.

9. The method according to claim 3, characterized in that, In step (4), the material used as liquid phase reflux accounts for 10-50% of the total mass fraction of the liquid product.

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