CN112830861B - Device and method for producing n-butane - Google Patents

Device and method for producing n-butane Download PDF

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CN112830861B
CN112830861B CN201911167322.4A CN201911167322A CN112830861B CN 112830861 B CN112830861 B CN 112830861B CN 201911167322 A CN201911167322 A CN 201911167322A CN 112830861 B CN112830861 B CN 112830861B
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hydrogenation
tower
butane
feeding
isobutane
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CN112830861A (en
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马立国
杨照
徐晓敏
徐垚
耿强
王鑫泉
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China Petroleum and Chemical Corp
Sinopec Engineering Inc
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China Petroleum and Chemical Corp
Sinopec Engineering Inc
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/005—Processes comprising at least two steps in series
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
    • C07C5/22—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by isomerisation
    • C07C5/27—Rearrangement of carbon atoms in the hydrocarbon skeleton
    • C07C5/2767—Changing the number of side-chains
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
    • C07C7/163—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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    • Y02P20/10—Process efficiency

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Abstract

The invention relates to a device and a method for producing n-butane, wherein the device comprises: the system comprises a light component removal tower, a normal butane finished product tower, a positive structured feeding and discharging heat exchanger, a positive structured feeding heater and a positive structured reaction unit, wherein a saturated liquefied gas feeding pipeline is connected with the light component removal tower; a discharge pipeline at the bottom of the light component removal tower is connected with a normal butane finished product tower; the top of the n-butane finished product tower is connected with an inlet of the positive structuring reaction unit; the outlet of the positive structure reaction unit is connected with a lightness-removing tower; a side line of the n-butane finished product tower is connected with an n-butane product extraction pipeline; the device is also provided with a saturated carbon four-feeding pipeline which is directly connected with the n-butane finished product tower and is rich in n/isobutane, and a high-purity isobutane feeding pipeline which is directly connected with the positive structured feeding and discharging heat exchanger. The invention can treat all raw materials rich in carbon-containing light hydrocarbons, including saturated liquefied gas, unsaturated liquefied gas, normal/isobutane mixture, high-purity isobutane and the like, and can recover waste heat, thereby improving the economic benefit of the device.

Description

Device and method for producing n-butane
Technical Field
The invention relates to the field of liquefied gas comprehensive utilization, in particular to a device and a method for producing n-butane.
Background
Along with the continuous deep processing of petrochemical industry, the processing depth of liquefied gas and oil is increasedC of by-product of field associated gas, oil refining plant and ethylene plant 4 The rational utilization of the components in the fractions is increasingly being appreciated. C 4 The 1,3-butadiene contained in the fraction can be separated by extractive distillation for producing synthetic rubber, C 4 Isobutene in the distillate reacts with methanol through an etherification device to generate MTBE and 1-butene with high purity can be obtained through further precise fractionation, and other four-carbon components are less utilized. N-butane can produce maleic anhydride, butene-1 and butadiene, with the greatest utility as an ethylene cracking feedstock, with a significantly greater triene yield than other carbon-tetrahydrocarbons. In recent years, the utilization of n-butane has attracted more and more attention with the weight reduction of ethylene raw materials.
The refinery has rich carbon four resources, and is divided into saturated liquefied gas containing no or a small amount of olefin (less than 5 percent) and unsaturated liquefied gas with higher olefin content (30-60 percent), the liquefied gases are mainly used for producing MTBE, alkylate oil and carbon four aromatization, but the approaches are gradually reduced and weakened by utilizing carbon four along with the surplus of oil refining capacity in China and the adjustment of ethanol gasoline policy. The carbon four behind the ether of the ethylene device is mainly alkane and mono-olefin, the content of the olefin is 30-60 wt%, most of the carbon four returns to the ethylene device to be used as cracking materials or produce other chemical products, but the olefin yield of a cracking furnace is limited due to the olefin and isoparaffin contained in the cracking furnace, the consumption of the carbon four for other chemical products is not large, and if the saturated or unsaturated liquefied gas can be converted into normal alkane to be sent to the ethylene device, and the ethylene, the propylene, the butadiene and the like with higher added value are increased, the benefit is remarkable.
CN104292065A and CN1170632A disclose a catalyst for preparing isobutane by isomerizing normal butane and an application thereof, but mainly comprise a catalyst system and process operation parameters, and are isomerization rather than normal isomerization and are not related to a process flow.
CN104892339A discloses a method for preparing n-butane from isobutane, which comprises the steps of putting carbon tetrahydrocarbon rich in isobutane into a normal formation area, converting isobutane into n-butane, enabling a material flow after reaction to enter a hydrogenation saturation area to carry out hydrogenation saturation on olefin, separating the material flow after hydrogenation into isobutane and n-butane, recycling isobutane to return to the normal formation area for reaction, and finally obtaining an n-butane product. The patent is only a conceptual flow and does not relate to specific details, and researches show that the lower the olefin content is required to be, the better the orthosteric reaction is, and otherwise the conversion rate and the selectivity of the orthosteric reaction are influenced, so whether the hydrogenation setting is reasonable or not directly influences the orthosteric result.
CN107285977A and CN107285978A disclose a system device for preparing n-butane by isobutane normal structure, the process comprises a normal structure reactor, a hydrogenation reactor, a lightness-removing tower, a butane tower and a weight-removing tower, the normal structure reaction is carried out under the hydrogen condition with the temperature of 400-550 ℃ and the pressure of 3-4.5 MPa, the purity of the separated n-butane product is 97.5-99 wt%, the technical process is complex, the lightness-removing tower, the weight-removing tower and the butane tower are needed, the normal structure reaction is carried out before hydrogenation, the carbon tetraolefin in the feed is easy to generate cracking, polymerization and other secondary reactions, the yield and selectivity of the normal structure are reduced, and the technical economy is influenced.
Disclosure of Invention
In order to solve the problems that a large amount of liquefied gas is not sufficiently utilized and the gap of normal paraffin requirements for lightening ethylene raw materials is large in the prior art, the invention provides a device and a method for producing normal butane. By combining hydrogenation and normalization processes, the invention can process various raw materials rich in carbon-containing four light hydrocarbons, including liquefied gas, oilfield associated gas, refinery carbon four, ethylene plant ether-containing carbon four and the like, can also process saturated liquefied gas, saturated carbon four rich in n/isobutane, and high-purity isobutane, and can also realize waste heat recovery and improve the economic benefit of the device by adopting a heat exchange network optimization technology.
One of the objects of the present invention is to provide an apparatus for producing n-butane, comprising: the system comprises a light component removal tower, an n-butane finished product tower, a positive structured feeding and discharging heat exchanger, a positive structured feeding heater and a positive structured reaction unit; wherein the content of the first and second substances,
the saturated liquefied gas feeding pipeline is connected with the light component removing tower;
a discharge pipeline at the bottom of the light component removal tower is connected with a normal butane finished product tower;
the top of the n-butane finished product tower is sequentially connected with a positive structure feeding and discharging heat exchanger and then connected with an inlet of a positive structure reaction unit; the outlet of the positive structure reaction unit is connected with a positive structure feeding and discharging heat exchanger and then connected with a lightness-removing tower; a side line of the n-butane finished product tower is connected with an n-butane product extraction pipeline;
the positive structure reaction unit comprises a single positive structure reactor or two positive structure reactors connected in series, and a positive structure feeding heater is arranged in front of each positive structure reactor;
the device is also provided with a saturated carbon four-feeding pipeline which is directly connected with the n-butane finished product tower and is rich in n/isobutane, and a high-purity isobutane feeding pipeline which is directly connected with the positive structured feeding and discharging heat exchanger.
According to the invention, when the raw material to be treated is unsaturated liquefied gas, the device can also comprise a hydrogenation reactor, a hydrogenation feeding and discharging heat exchanger, a hydrogenation feeding heater and a hydrogenation separation device; wherein the content of the first and second substances,
the unsaturated liquefied gas feeding pipeline is connected with the hydrogenation feeding and discharging heat exchanger and the hydrogenation feeding heater and then is connected with the upper part of the hydrogenation reactor;
the bottom of the hydrogenation reactor is connected with a hydrogenation charging and discharging heat exchanger and then connected with a hydrogenation separation device, and the top of the hydrogenation separation device is sequentially connected with a compressor suction tank, a compressor and then combined with an unsaturated liquefied gas feeding pipeline and then connected with the hydrogenation charging and discharging heat exchanger;
the bottom of the hydrogenation separation device is connected with a lightness-removing column.
The hydrogenation separation device is arranged for separating hydrogen and light hydrocarbon, and can adopt one of the following two compositions:
a) The hydrogenation separation device comprises a hydrogenation thermal separation tank, a hydrogenation aftercooler and a hydrogenation cold separation tank;
the bottom of the hydrogenation reactor is connected with a hydrogenation charging and discharging heat exchanger and then connected with a hydrogenation heat separation tank, the top of the hydrogenation heat separation tank is sequentially connected with a hydrogenation aftercooler and a hydrogenation cold separation tank, and the top of the hydrogenation cold separation tank is connected with a compressor suction tank; the bottom of the hydrogenation cold separation tank is connected with a hydrogenation hot separation tank; the bottom of the hydrogenation thermal separation tank is connected with a light component removal tower.
B) The hydrogenation separation device can also comprise a hydrogenation aftercooler and a hydrogenation separation tank;
the bottom of the hydrogenation reactor is connected with a hydrogenation charging and discharging heat exchanger and then sequentially connected with a hydrogenation aftercooler and a hydrogenation separation tank, the top of the hydrogenation separation tank is connected with a compressor suction tank, and the bottom of the hydrogenation separation tank is connected with a light component removal tower.
According to two hydrogenation separation devices, after reaction discharge is subjected to heat exchange through a hydrogenation feed and discharge heat exchanger, two modes can be provided, wherein one mode is that the reaction discharge is firstly fed into a hydrogenation heat separation tank for gas-liquid separation, a top gas phase is cooled through a hydrogenation aftercooler and then fed into a hydrogenation cold separation tank, the top of the hydrogenation cold separation tank is connected with a compressor suction tank, the bottom of the hydrogenation cold separation tank is connected with the hydrogenation heat separation tank, and a liquid phase at the bottom of the hydrogenation heat separation tank is connected with a light component removal tower (as shown in figure 3); the other mode is that the mixture is cooled by a cooler after hydrogenation and then enters a hydrogenation separation tank for gas-liquid separation, the top gas phase is connected with a compressor suction tank, and the bottom liquid phase is connected with a light component removal tower (as shown in figure 4). The present invention preferably adopts the first mode.
The above-described heater for the hydrogenation feed may be a heating device generally used in the art, such as: an electric heater, a steam heater, or a furnace.
The invention also aims to provide a method for producing n-butane by using the device, which comprises at least one of the following three process flows:
the process flow I:
(1) Saturated liquefied gas enters a lightness-removing tower to remove light components (C) 1 ～C 3 Etc.) then enters a normal butane finished product tower, normal butane products are obtained from the side line of the tower through rectification separation, carbon five-component components are obtained from the tower bottom, and C rich in isobutane is extracted from the tower top 4 Logistics;
(2) Said isobutane rich C 4 The material flow enters a positive structure reaction unit through a positive structure feeding and discharging heat exchanger to carry out positive structure reaction, and isobutane is converted into normal butane;
(3) After the positive structure reaction obtained by the positive structure reaction unit, the carbon four enters a lightness-removing tower after heat exchange by a positive structure feeding and discharging heat exchanger;
and the process flow II:
(1) Saturated carbon IV rich in n/isobutane enters a n-butane finished product tower,the normal butane product is obtained from the side line of the tower through rectification separation, the carbon five-component is obtained from the bottom of the tower, and the C rich in isobutane is extracted from the top of the tower 4 Logistics;
(2) Said isobutane rich C 4 The material flow enters a positive structure reaction unit through a positive structure feeding and discharging heat exchanger to carry out positive structure reaction, and isobutane is converted into normal butane;
(3) After the positive structure reaction obtained by the positive structure reaction unit, the carbon four enters a lightness-removing tower after heat exchange by a positive structure feeding and discharging heat exchanger;
the process flow III:
(1) High-purity isobutane outside the world is used as a normal structure feed and enters a normal structure reaction unit through a normal structure feed and discharge heat exchanger to carry out normal structure reaction, and the isobutane is converted into normal butane;
(2) After the positive structure reaction obtained by the positive structure reaction unit, the carbon four enters a lightness-removing tower after heat exchange by a positive structure feeding and discharging heat exchanger;
(3) The material flow at the bottom of the light component removal tower enters a normal butane finished product tower, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained at the bottom of the tower, and C rich in isobutane is extracted at the top of the tower 4 Logistics;
(4) Said isobutane rich C 4 The material flow enters a positive structure reaction unit for positive structure reaction after heat exchange through a positive structure feeding and discharging heat exchanger.
According to the invention, a single or two reactors can be arranged in series in the normalization reaction unit, preferably two reactors are used. Under these conditions, process scheme I preferably includes the following steps:
(1) Saturated liquefied gas enters a lightness removing tower to remove light components and then enters an n-butane finished product tower, an n-butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the bottom of the tower, and C rich in isobutane is extracted from the top of the tower 4 Logistics;
(2) Said isobutane rich C 4 The material flow enters a first positive reactor after being subjected to heat exchange by a positive structure feeding and discharging heat exchanger and a first positive structure feeding heater to carry out positive structure reaction, and isobutane is converted into n-butaneThen the mixture is heated by a second normalization feeding heater and then enters a second normalization reactor to continue the normalization reaction;
(3) And after the normalization reaction obtained at the bottom of the second normalization reactor, the carbon four enters a light component removal tower after heat exchange of the normalization feeding and discharging heat exchanger.
Process scheme II preferably comprises the following steps:
(1) Feeding saturated carbon IV rich in n/isobutane into a normal butane finished product tower, obtaining a normal butane product from a side line of the tower through rectification separation, obtaining a carbon five-component from a tower kettle, and extracting C rich in isobutane from the tower top 4 Logistics;
(2) Said isobutane rich C 4 The material flow enters a first positive structure reactor after being subjected to heat exchange through a positive structure feeding and discharging heat exchanger and a first positive structure feeding heater, positive structure reaction is carried out, isobutane is converted into n-butane, and then the n-butane is heated by a second positive structure feeding heater and enters a second positive structure reactor, and positive structure reaction is continuously carried out;
(3) And after the normalization reaction obtained at the bottom of the second normalization feeding heater, carbon four enters the lightness-removing tower after heat exchange by the normalization feeding and discharging heat exchanger.
Process scheme III preferably includes the following steps:
(1) High-purity isobutane outside the world is used as a normal structured feed, enters a first normal structured reactor after heat exchange through a normal structured feed and discharge heat exchanger and a first normal structured feed heater, carries out normal structured reaction, converts the isobutane into normal butane, enters a second normal structured reactor after being heated by a second normal structured feed heater, and continues to carry out the normal structured reaction;
(2) After the normalization reaction obtained at the bottom of the second normalization reactor, the carbon four enters a lightness-removing tower after heat exchange by a normalization charging and discharging heat exchanger;
(3) The material flow at the bottom of the light component removal tower enters a normal butane finished product tower, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained at the bottom of the tower, and C rich in isobutane is extracted at the top of the tower 4 Logistics;
(4) Said isobutane rich C 4 After the material flows through the positive structure feeding and discharging heat exchanger for heat exchangeEntering a normalization reaction unit for normalization.
The method can be used for independently treating the saturated liquefied gas, the saturated carbon four rich in normal/isobutane, the high-purity isobutane, any two of the saturated liquefied gas, the saturated carbon four rich in normal/isobutane and the high-purity isobutane, and the three can be simultaneously treated.
According to a preferred embodiment of the present invention, the method for simultaneously treating a saturated liquefied gas, a saturated carbon four rich in n/isobutane and high-purity isobutane comprises the steps of:
(i) The carbon four obtained after the normal formation reaction of the saturated liquefied gas and the normal formation reaction unit after heat exchange enters a lightness-removing tower, the removed light components and the saturated carbon four rich in normal/isobutane outside the world enter a normal butane finished product tower together, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the bottom of the tower, and the C rich in isobutane is extracted from the top of the tower 4 Logistics;
(ii) Said isobutane rich C 4 After being mixed with high-purity isobutane coming from outside, the material flow enters a normal formation reaction unit through a normal formation charging and discharging heat exchanger to carry out normal formation reaction, and the isobutane is converted into normal butane;
(iii) And after the normalization reaction obtained by the normalization reaction unit, the carbon four enters the lightness-removing tower after heat exchange by the normalization feeding and discharging heat exchanger.
According to a more preferred embodiment, the process for simultaneously treating a saturated liquefied gas, a saturated carbon four rich in n/isobutane and a high purity isobutane comprises the steps of:
(i) The saturated liquefied gas and the normalized carbon IV obtained at the bottom of the second normalized reactor after heat exchange enter a lightness-removing tower after the normalization reaction, the removed light components and the saturated carbon IV rich in normal/isobutane outside the world enter a normal butane finished product tower together, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon quintuple component is obtained from the bottom of the tower, and the C rich in isobutane is extracted from the top of the tower 4 Logistics;
(ii) Said isobutane rich C 4 Material flow and high-purity isobutane coming from outside through positive structuringThe heat exchanger and the first positive structure feeding heater are used for exchanging heat and then enter the first positive structure reactor for positive structure reaction, isobutane is converted into normal butane, and then the normal structure feeding heater is used for heating and then enters the second positive structure reactor for continuous positive structure reaction;
(iii) And after the normalization reaction obtained at the bottom of the second normalization reactor, the carbon four enters a light component removal tower after heat exchange of the normalization feeding and discharging heat exchanger.
According to the present invention, the process of the present invention can also treat unsaturated liquefied gases when the plant contains a hydrotreatment unit, in particular the process comprises the following steps:
(a) Unsaturated liquefied gas from outside enters a hydrogenation reactor to hydrogenate and saturate olefins and remove impurities after heat exchange by a hydrogenation feeding and discharging heat exchanger; the impurities include trace organic sulfur and nitrogen, which can be converted into H 2 S and NH 3 ；
(b) The bottom discharge of the hydrogenation reactor enters a hydrogenation separation device after passing through a hydrogenation feeding and discharging heat exchanger, the separated hydrogen enters a compressor through a compressor suction tank and then returns to the hydrogenation reactor, and the bottom material of the hydrogenation separation device enters a light component removal tower;
(c) The bottom material of the light component removal tower enters a normal butane finished product tower, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the tower kettle, and C rich in isobutane is extracted from the tower top 4 Logistics;
(d) Said isobutane rich C 4 The material flow enters a positive structure reaction unit through a positive structure feeding and discharging heat exchanger to carry out positive structure reaction, and isobutane is converted into normal butane;
(e) And after the normalization reaction obtained by the normalization reaction unit, the carbon four is subjected to heat exchange by a normalization feeding and discharging heat exchanger and then enters the light component removal tower together with the material at the bottom of the hydrogenation separation device.
According to a more specific embodiment, the method comprises the steps of:
(a) Unsaturated liquefied gas from outside enters a hydrogenation reactor to hydrogenate and saturate olefins and remove impurities after heat exchange by a hydrogenation feeding and discharging heat exchanger; the impurities include trace organic sulfur and nitrogen, andconvert it to H 2 S and NH 3 ；
(b) The bottom discharge of the hydrogenation reactor enters a hydrogenation separation device after passing through a hydrogenation feeding and discharging heat exchanger, the separated hydrogen enters a compressor through a compressor suction tank and then returns to the hydrogenation reactor, and the bottom material of the hydrogenation separation device enters a light component removal tower;
(c) The bottom material of the light component removal tower enters a normal butane finished product tower, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the tower kettle, and C rich in isobutane is extracted from the tower top 4 Logistics;
(d) Said isobutane rich C 4 The material flow enters a first positive structure reactor after being subjected to heat exchange through a positive structure feeding and discharging heat exchanger and a first positive structure feeding heater, is subjected to positive structure reaction, is converted into normal butane through isobutane, then enters a second positive structure reactor after being heated by a second positive structure feeding heater, and is subjected to positive structure reaction continuously;
(e) And after the normalization reaction obtained at the bottom of the second normalization reactor, the carbon four is subjected to heat exchange by a normalization feeding and discharging heat exchanger and then enters the light component removal tower together with the bottom material of the hydrogenation separation device.
In the step (a), the unsaturated liquefied gas is heated to 160-300 ℃ and then enters a hydrogenation reactor. If the temperature rise of the hydrogenation reaction is very high, the temperature rise of a hydrogenation feeding heater is not needed during normal production, the reaction temperature can be reached through the heat exchange of feeding and discharging materials, the hydrogenation feeding heater is needed only during starting, and at the moment, the materials subjected to the heat exchange of the hydrogenation feeding and discharging heat exchanger can directly enter the hydrogenation reactor through a pipeline. If the temperature rise of the hydrogenation reaction is not high, a hydrogenation feeding heater is required for heating besides feeding and discharging heat exchange during normal production.
In the step (b), when the hydrogenation separation device comprises a hydrogenation heat separation tank, a hydrogenation aftercooler and a hydrogenation cold separation tank, the discharge material at the bottom of the hydrogenation reactor is cooled to 50-100 ℃ through a hydrogenation feed and discharge heat exchanger and then enters the hydrogenation heat separation tank, and the gas phase at the top of the hydrogenation heat separation tank is cooled to 20-50 ℃ through the hydrogenation aftercooler and then enters the hydrogenation cold separation tank.
In the step (b), when the hydrogenation separation device comprises a hydrogenation aftercooler and a hydrogenation separation tank, the material at the bottom of the hydrogenation reactor is subjected to heat exchange through a hydrogenation feeding and discharging heat exchanger, then is cooled to 20-50 ℃ through the hydrogenation aftercooler, and then enters the hydrogenation separation tank.
The hydrogenation catalyst adopted by the invention is a nickel-based or palladium-based hydrogenation catalyst; the normal structuring catalyst is a catalyst composed of one or two of Pt, pd and Ir.
The process conditions of each apparatus of the present invention may be those generally used in the prior art, and in the present invention, the following process conditions may be preferably used:
the normal structuring reactor is a fixed bed reactor, and the operation conditions comprise: the inlet temperature of the reactor is 100-250 ℃, the pressure is 1.0-4.0 MPaG (gauge pressure, the same below), and the liquid volume space velocity is 1-20 h -1 . When two normalization reactors are used, both normalization reactors use the above-described format and operating conditions.
The operating conditions of the light component removal tower comprise: the pressure is 1-3 MPaG, the operation temperature at the top of the tower is 30-90 ℃, and the number of tower plates is 30-150.
The operating conditions of the n-butane finished product tower comprise: the pressure is 0.1-1 MPaG, the operation temperature at the top of the tower is 20-70 ℃, and the number of tower plates is 50-150.
The hydrogenation reactor is a fixed bed reactor, and the operation conditions comprise: the inlet temperature of the reactor is 160-300 ℃, the pressure is 1.5-4.5 MPaG, the molar ratio of hydrogen to oil is 0.2-5, and the liquid volume space velocity is 0.5-6 h -1 。
The apparatus and method of the present invention can process at least one of four types of incoming material: saturated liquefied gas, saturated carbon four rich in normal/isobutane, high-purity isobutane and unsaturated liquefied gas. The meaning and scope of the above concepts are well known to those skilled in the art. Wherein the saturated liquefied gas is a component rich in propane, isobutane, n-butane and a small amount of carbon two, carbon three and carbon five alkanes, wherein the content of olefin is less than 1wt%; the n/isobutane-rich saturated carbon four is a stream rich in isobutane and n-butane with the olefin content of less than 1wt%, and can be from a gas separation device, an MTBE device, an isobutane device and the like; the high-purity isobutane is a carbon-four stream with the isobutane content higher than 90wt% and the olefin content less than 1wt%, and can be from an MTBE device, an isobutane production device and the like; the unsaturated liquefied gas is at least one of oil field associated gas, gas field associated gas, refinery liquefied gas and ethylene plant ether post-carbon four, wherein the olefin content is 5-90 wt%.
The invention has the beneficial effects that:
1) Unsaturated olefin is completely converted into saturated hydrocarbon by hydrogenation, and impurities such as organic sulfur, nitrogen and the like in the raw material are converted into H 2 S and NH 3 And the removal is carried out, so that the influence on the product is avoided.
2) Isobutane is converted into n-butane through normal structuring, and the conversion rate and selectivity of the main reaction are improved by optimizing reaction parameters.
3) Through reasonable setting of the heat exchange sequence, energy is recovered to the maximum extent, the energy consumption of the system is reduced, the energy consumption of the rectifying tower is reduced through design optimization of the rectifying tower, the economic benefit of the device is improved through a series of means, and the energy consumption is saved by more than 15% in total.
4) The temperature of the tower kettle is lower than 150 ℃ and the temperature of the tower top is about 45 ℃ through proper operating parameters, heat exchange can be realized by adopting low-pressure steam and circulating cooling water which are low in price, and high-grade steam and high-quality chilled water do not need to be externally introduced.
5) Through reasonable flow setting, different feeding positions are selected for different carbon four raw materials.
6) The invention can process all light hydrocarbons rich in carbon four by combining hydrogenation and normal structuring processes, and is used for producing n-butane.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, wherein like reference numerals generally represent like parts in the exemplary embodiments of the present invention.
FIG. 1 is a schematic view of an apparatus for producing n-butane according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of an apparatus for producing n-butane according to another embodiment of the present invention.
FIG. 3 is a schematic view of an apparatus for producing n-butane according to still another embodiment of the present invention.
FIG. 4 is a schematic view of an apparatus for producing n-butane according to a fourth embodiment of the present invention.
Description of the reference numerals
1. A hydrogenation reactor; 2. a hydrogenation feed and discharge heat exchanger; 3. a hydrogenation feed heater; 4. a hydrogenation aftercooler; 5. a hydro-separation tank; 6. a hydrogenation thermal separation tank; 7. a hydrogenation cooling separation tank; 8. a compressor suction canister; 9. a compressor; 11. a light component removal tower; 12. a condenser of the light component removal tower; 13. a reboiler of the light component removal tower; 14. a n-butane finished product tower; 15. a condenser of a n-butane finished product tower; 16. a n-butane finished product tower reboiler; 17. a structured feed and discharge heat exchanger; 18A, a first positive structured feed heater; 18B, a second positive feed heater; 19A, a first normalizing reactor; 19B, a second orthosteric reactor; 20. unsaturated liquefied gas; 21. a saturated liquefied gas; 22. normalizing the make-up hydrogen; 23. bleeding and discharging gas; 24. adding hydrogen to supplement hydrogen; 25. non-condensable gas at the top of the light component removal tower; 26. c 2 /C 3 Liquid phase; 27. a n-butane product; 28. five carbon heavy components; 29. high-purity isobutane; 30. saturated carbon four rich in normal/iso-butane.
Detailed Description
Preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.
Example 1
An apparatus for producing n-butane as shown in FIG. 1 was used.
The device includes: the system comprises a light component removal tower 11, a n-butane finished product tower 14, a structured feeding and discharging heat exchanger 17, a structured feeding heater 18A and a structured reaction unit, wherein the structured reaction unit comprises a single structured reactor, namely a first structured reactor 19A; wherein, the first and the second end of the pipe are connected with each other,
the saturated liquefied gas feeding pipeline is connected with a lightness-removing tower 11;
the discharge pipeline at the bottom of the lightness-removing tower 11 is connected with a normal butane finished product tower 14, and the bottom of the lightness-removing tower 11A reboiler 13 of the light component removal tower is arranged, the top of the light component removal tower 11 is connected with a condenser 12 of the light component removal tower, the uncondensed part is discharged as non-condensable gas 25 at the top of the light component removal tower, and the liquid phase obtained by condensation and a discharge pipeline at the top of the light component removal tower 11 are used as C 2 /C 3 The liquid phase 26 is discharged;
the top of the n-butane finished product tower 14 is connected with an n-butane finished product tower condenser 15, and the obtained liquid and the discharge at the upper part of the n-butane finished product tower 14 are sequentially connected with a positive structured feeding and discharging heat exchanger 17 and a positive structured feeding heater 18A, and then are connected with the top inlet of a first positive structured reactor 19A; the outlet at the bottom of the first positive structure reactor 19A is connected with the positive structure feed and discharge heat exchanger 17 and then connected with the lightness-removing tower 11; a n-butane product extraction pipeline is connected to the side line of the n-butane finished product 14 tower;
the device is also provided with a saturated carbon four feeding pipeline which is directly connected with the n-butane finished product tower 11 and is rich in n/isobutane, a high-purity isobutane feeding pipeline which is directly connected with the positive structure feeding and discharging heat exchanger 17, and a positive structure supplementing hydrogen feeding pipeline.
The method for producing the n-butane by using the device comprises the following steps:
(i) The saturated liquefied gas 21 and the normalized carbon four obtained at the bottom of the first normalized reactor 19A after heat exchange enter a lightness-removing tower 11, the removed light components and the saturated carbon four 30 rich in normal/isobutane enter a normal butane finished product tower 14 together, a normal butane product 27 is obtained from the side line of the tower through rectification separation, the carbon five-component is obtained from the tower bottom, and the C rich in isobutane is collected from the tower top 4 Logistics;
(ii) Said isobutane rich C 4 The material flow and the normal structure make-up hydrogen 22 and the high purity isobutane 29 from outside enter a first normal structure reactor 19A after heat exchange through a normal structure feeding and discharging heat exchanger 17 and a normal structure feeding heater 18A, normal structure reaction is carried out, and the isobutane is converted into normal butane;
(iii) The carbon four obtained from the bottom of the first normalizing reactor 19A after the normalizing reaction enters the lightness-removing tower 11 after the heat exchange of the normalizing feed-discharge heat exchanger 17.
The method for producing the n-butane adopts the following process conditions:
the operating conditions of the light ends removal column 11 include: the pressure is 1.8MPaG, the operation temperature at the top of the tower is 50 ℃, and the number of tower plates is 80;
the operating conditions of the n-butane finishing tower 14 include: the pressure is 0.5MPaG, the operation temperature at the top of the tower is 45 ℃, and the number of tower plates is 130;
the first normal reactor 19A is a descending fixed bed reactor with a reactor inlet temperature of 160 deg.C, a pressure of 3.3MPaG, a reaction temperature of 30 deg.C, and a liquid volume space velocity of 10h -1 。
The results obtained by the above process are shown in table 1.
The result shows that when the device and the method are used for preparing the normal butane, the conversion rate of the isobutane is more than or equal to 50 percent, and the selectivity of the generated normal butane is more than or equal to 80 percent.
Table 1 example 1 material balance table
Figure BDA0002287797910000131
Example 2
An apparatus for producing n-butane as shown in FIG. 2 was used.
The device includes: the system comprises a light component removal tower 11, an n-butane finished product tower 14, a positive structure feeding and discharging heat exchanger 17, a positive structure feeding heater and a positive structure reaction unit, wherein the positive structure reaction unit comprises two positive structure reactors connected in series, namely a first positive structure reactor 19A and a second positive structure reactor 19B, and the positive structure feeding heater is arranged in front of each positive structure reactor, namely a first positive structure feeding heater 18A and a second positive structure feeding heater 18B; wherein, the first and the second end of the pipe are connected with each other,
a saturated liquefied gas feeding pipeline 21 is connected with the light component removal tower 11;
the discharge pipeline at the bottom of the lightness-removing tower 11 is connected with a normal butane finished product tower 14, the bottom of the lightness-removing tower 11 is provided with a lightness-removing tower reboiler 13, the top of the lightness-removing tower 11 is connected with a lightness-removing tower condenser 12, the uncondensed part is discharged as the non-condensable gas 25 at the top of the lightness-removing tower, the liquid phase obtained by condensation and the discharge pipeline at the top of the lightness-removing tower 11 are used as C 2 /C 3 The liquid phase 26 is discharged;
the top of the n-butane finished product tower 14 is connected with an n-butane finished product tower condenser 15, and the obtained liquid and the discharge at the upper part of the n-butane finished product tower 14 are sequentially connected with a positive structure feed and discharge heat exchanger 17 and a first positive structure feed heater 18A, and then are connected with the top inlet of a first positive structure reactor 19A; the bottom outlet of the first normalization reactor 19A is connected with a second normalization feed heater 18B, then is connected with the top inlet of the second normalization reactor 19B, and the bottom outlet of the second normalization reactor 19B is connected with a normalization feed-discharge heat exchanger 17 and then is connected with the lightness-removing tower 11; a n-butane product extraction pipeline is connected to the side line of the n-butane finished product 14 tower;
the device is also provided with a saturated carbon four-feeding pipeline which is directly connected with the n-butane finished product tower 14 and is rich in normal/iso-butane, a high-purity iso-butane feeding pipeline which is directly connected with the normal structured feeding and discharging heat exchanger 17, and a normal structured supplementary hydrogen feeding pipeline.
The method for producing the n-butane by using the device comprises the following steps:
(i) The saturated liquefied gas 21 and the carbon four obtained after the normalization reaction at the bottom of the second normalization reactor 19B after heat exchange enter a lightness-removing tower 11, the removed light components and the saturated carbon four 30 rich in n/isobutane enter a normal butane finished product tower 14 together, a normal butane product 27 is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the bottom of the tower, and the C rich in isobutane is extracted from the top of the tower 4 Logistics;
(ii) Said isobutane rich C 4 The material flow and the normal formation supplementary hydrogen 22 and high-purity isobutane 29 from outside enter a first normal formation reactor 19A after heat exchange through a normal formation charging and discharging heat exchanger 17 and a first normal formation charging heater 18A to carry out normal formation reaction, the isobutane is converted into normal butane, and then enters a second normal formation reactor 19B after being heated by a second normal formation charging heater 18B to continue the normal formation reaction;
(iii) Carbon four obtained from the bottom of the second normalizing reactor 19B after the normalizing reaction enters the lightness-removing tower 11 after heat exchange by the normalizing feed-discharge heat exchanger 17.
The method for producing the n-butane adopts the following process conditions:
the operating conditions of the light ends removal column 11 include: the pressure is 1.8MPaG, the operation temperature at the top of the tower is 50 ℃, and the number of tower plates is 80;
the operating conditions of the n-butane finishing tower 14 include: the pressure is 0.5MPaG, the operation temperature at the top of the tower is 45 ℃, and the number of tower plates is 130;
the two normal structure reactors are down-flow fixed bed reactors, the inlet temperature of the reactor is 160 ℃, the pressure is 3.3MPaG, the reaction temperature is 30 ℃, and the liquid volume space velocity is 10h -1 。
The results obtained by the above process are shown in table 2.
The result shows that when the device and the method of the embodiment are used for preparing the n-butane, the conversion rate of the isobutane is more than or equal to 50 percent, and the selectivity of the generated n-butane is more than or equal to 80 percent.
Table 2 example 2 material balance table
Figure BDA0002287797910000151
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Example 3
An apparatus for producing n-butane as shown in FIG. 3 was used.
The device includes: the device comprises a hydrogenation reactor 1, a hydrogenation charging and discharging heat exchanger 2, a hydrogenation feeding heater 3, a hydrogenation separation device, a light component removal tower 11, an n-butane finished product tower 14, a positive structured charging and discharging heat exchanger 17, a first positive structured charging heater 18A, a second positive structured charging heater 18B, a first positive structured reactor 19A and a second positive structured reactor 19B; wherein the content of the first and second substances,
the unsaturated liquefied gas feeding pipeline is connected with the hydrogenation feeding and discharging heat exchanger 2 and the hydrogenation feeding heater 3 and then is connected with the upper part of the hydrogenation reactor 1;
the bottom of the hydrogenation reactor 1 is connected with a hydrogenation charging and discharging heat exchanger 2 and then connected with a hydrogenation heat separation tank 6; the top of the hydrogenation thermal separation tank 6 is sequentially connected with a hydrogenation aftercooler 4 and a hydrogenation cold separation tank 7, the top of the hydrogenation cold separation tank 7 is sequentially connected with a compressor suction tank 8 and a compressor 9, then is combined with a four-carbon feeding pipeline, and then is connected with a hydrogenation feeding and discharging heat exchanger 2; the bottom of the hydrogenation cold separation tank 7 is connected with a hydrogenation hot separation tank 6; the bottom of the hydrogenation thermal separation tank 6 is connected with a light component removal tower 11;
the discharge pipeline at the bottom of the lightness-removing tower 11 is connected with a normal butane finished product tower 14, and the bottom of the lightness-removing tower 11 is provided with lightness-removing liquidA tower reboiler 13, the top of the lightness-removing tower 11 is connected with a lightness-removing tower condenser 12, the uncondensed part is discharged as the non-condensable gas 25 at the top of the lightness-removing tower, the liquid phase obtained by condensation and the discharge pipeline at the top of the lightness-removing tower 11 are used as C 2 /C 3 The liquid phase 26 is discharged;
the top of the n-butane finished product tower 14 is connected with an n-butane finished product tower condenser 15, the obtained liquid and the discharge material at the upper part of the n-butane finished product tower 14 are sequentially connected with a positive structure feed and discharge heat exchanger 17 and a first positive structure feed heater 18A and then connected with the top inlet of a first positive structure reactor 19A, and the bottom outlet of the first positive structure reactor 19A is connected with the top inlet of a second positive structure reactor 19B after being connected with a second positive structure feed heater 18B; the outlet at the bottom of the positive structure reactor 19B is connected with the positive structure feed and discharge heat exchanger 17 and then connected with the lightness-removing tower 11; a n-butane product extraction pipeline is connected to the side line of the n-butane finished product 14 tower;
the device is also provided with a saturated carbon four-feeding pipeline which is directly connected with the n-butane finished product tower and is rich in normal/iso-butane, a high-purity iso-butane feeding pipeline which is directly connected with the normal structured feeding and discharging heat exchanger 17, and a normal structured supplementary hydrogen feeding pipeline.
The method for producing the n-butane by using the device comprises the following steps:
(a) Unsaturated liquefied gas 20 outside the world and hydrogen returned by a compressor are mixed, enter a hydrogenation charging and discharging heat exchanger 2, are heated to 240 ℃ by a hydrogenation charging heater 3, and finally enter a hydrogenation reactor 1 to hydrogenate and saturate olefins and convert trace organic sulfur nitrogen into H 2 S and NH 3 ；
(b) The bottom discharge of a hydrogenation reactor 1 is cooled to 80 ℃ after heat exchange with hydrogenation feed, and then the bottom discharge is firstly fed into a hydrogenation heat separation tank 6 for gas-liquid separation, the top gas phase is cooled to 40 ℃ through a hydrogenation aftercooler 4 and then fed into a hydrogenation cold separation tank 7, the top gas phase of the hydrogenation cold separation tank 7 is fed into a compressor 9 through a compressor suction tank 8, most of the top gas phase is returned to the hydrogenation reactor 1 as circulating hydrogen, and the discharging gas 21 is released through a discharging pipeline to maintain the content of non-hydrogen gas in a circulating hydrogen system to be stable, the bottom of the hydrogenation cold separation tank 7 is connected with the hydrogenation heat separation tank 6, and the bottom liquid phase of the hydrogenation heat separation tank 6 is fed into a lightness removing tower 11;
(c) Fresh hydrogen as hydrogenation supplementary hydrogen 24 is combined with gas at the top of a compressor suction tank 8 from the outside and enters a compressor 9, and the fresh hydrogen and unsaturated liquefied gas 20 enter a hydrogenation charging and discharging heat exchanger 2 together after being pressurized by the compressor 9;
(d) The material at the bottom of the hydrogenation thermal separation tank 6 and the carbon four and saturated liquefied gas 21 after the positive structure reaction are mixed and enter a lightness-removing tower 11, and H is removed from the gas phase at the top of the tower through rectification separation 2 S，NH 3 The non-condensable gas is waited, the liquid phase removes light components such as carbon two, carbon three, etc., the bottom material and saturated carbon four 30 rich in normal/iso butane enter the normal butane finished product tower 14 together, the normal butane product 27 is obtained from the lateral line of the normal butane finished product tower 14 through rectification separation, the carbon five heavy components 28 are obtained from the tower kettle;
(e) Mixing a mixture rich in isobutane extracted from the top of a normal butane finished product tower 14 with fresh hydrogen outside, namely normalized supplemental hydrogen 22 and high-purity isobutane 29, heating to 160 ℃ through a normalized feed-discharge heat exchanger 17 and a first normalized feed heater 18A, then feeding into a first normalized reactor 19A, converting the isobutane into normal butane, discharging from the first normalized reactor 19A, heating to 160 ℃ through a second normalized feed heater 18B, and then feeding into a second normalized reactor 19B for continuous normalization;
(f) The carbon four material obtained from the second positive structure feeding heater 19B after the positive structure reaction enters the light component removing tower 11 after heat exchange of the positive structure feeding and discharging heat exchanger 17.
The method for producing the n-butane adopts the following process conditions:
the hydrogenation reactor 1 is a descending fixed bed reactor, the inlet temperature of the reactor is 240 ℃, the pressure is 3MPaG, the reaction temperature rises to 25 ℃, the hydrogen-oil molar ratio is 1.1, and the liquid volume space velocity is 2.0h -1 ；
The operating conditions of the light ends removal column 11 include: the pressure is 1.8MPaG, the operation temperature at the top of the tower is 50 ℃, and the number of tower plates is 80;
the operating conditions of the n-butane finishing tower 14 include: the pressure is 0.5MPaG, the operation temperature at the top of the tower is 45 ℃, and the number of tower plates is 130;
the two positive reactors are down-flow fixed bed reactors, the inlet temperature of the reactors is 160 ℃, the pressure is 3.3MPaG, and the reaction temperature is 30 DEG CThe liquid volume space velocity is 10h -1 。
The results obtained by the above process are shown in table 3.
The result shows that the device and the method for preparing the n-butane have the olefin content of less than or equal to 1000ppm after hydrogenation, the isobutane conversion rate of more than or equal to 50 percent in the normal structuring reaction and the n-butane generation selectivity of more than or equal to 80 percent.
Table 3 example 3 material balance table
Figure BDA0002287797910000181
Figure BDA0002287797910000191
Example 4
An apparatus for producing n-butane as shown in FIG. 4 was used.
The device includes: the device comprises a hydrogenation reactor 1, a hydrogenation charging and discharging heat exchanger 2, a hydrogenation feeding heater 3, a hydrogenation separation device, a light component removal tower 11, an n-butane finished product tower 14, a positive structured charging and discharging heat exchanger 17, a first positive structured charging heater 18A, a second positive structured charging heater 18B, a first positive structured reactor 19A and a second positive structured reactor 19B; wherein the content of the first and second substances,
the unsaturated liquefied gas feeding pipeline is connected with the hydrogenation feeding and discharging heat exchanger 2 and the hydrogenation feeding heater 3 and then is connected with the upper part of the hydrogenation reactor 1;
the bottom of the hydrogenation reactor 1 is connected with a hydrogenation charging and discharging heat exchanger 2 and then connected with a hydrogenation aftercooler 4 and a hydrogenation separation tank 5; the top of the hydrogenation separation tank 5 is sequentially connected with a compressor suction tank 8 and a compressor 9, then is combined with a four-carbon feeding pipeline, and then is connected with a hydrogenation feeding and discharging heat exchanger 2; the bottom of the hydrogenation separation tank 5 is connected with a light component removal tower 11;
the discharge pipeline at the bottom of the lightness-removing tower 11 is connected with a normal butane finished product tower 14, the bottom of the lightness-removing tower 11 is provided with a lightness-removing tower reboiler 13, the top of the lightness-removing tower 11 is connected with a lightness-removing tower condenser 12, the uncondensed part is discharged as the non-condensable gas 25 at the top of the lightness-removing tower, the liquid phase obtained by condensation and the discharge pipeline at the top of the lightness-removing tower 11 are used asIs C 2 /C 3 The liquid phase 26 is discharged;
the top of the n-butane finished product tower 14 is connected with an n-butane finished product tower condenser 15, the obtained liquid and the discharge at the upper part of the n-butane finished product tower 14 are sequentially connected with a positive structured feed and discharge heat exchanger 17 and a first positive structured feed heater 18A and then connected with the top inlet of a first positive structured reactor 19A, the bottom outlet of the first positive structured reactor 19A is connected with a second positive structured feed heater 18B and then connected with the top inlet of a second positive structured reactor 19B; the outlet at the bottom of the positive structure reactor 19B is connected with the positive structure feed and discharge heat exchanger 17 and then connected with the lightness-removing tower 11; a n-butane product extraction pipeline is connected to the side line of the n-butane finished product 14 tower;
the device is also provided with a saturated carbon four-feeding pipeline which is directly connected with the n-butane finished product tower and is rich in normal/iso-butane, a high-purity iso-butane feeding pipeline which is directly connected with the normal structured feeding and discharging heat exchanger 17, and a normal structured supplementary hydrogen feeding pipeline.
The method for producing the n-butane by using the device comprises the following steps:
(a) Unsaturated liquefied gas 20 outside the world and hydrogen returned by a compressor are mixed, enter a hydrogenation charging and discharging heat exchanger 2, are heated to 240 ℃ by a hydrogenation charging heater 3, and finally enter a hydrogenation reactor 1 to hydrogenate and saturate olefins and convert trace organic sulfur nitrogen into H 2 S and NH 3 ；
(b) The discharge from the bottom of the hydrogenation reactor 1 is subjected to heat exchange with the hydrogenation feed, then cooled to 80 ℃, then enters a hydrogenation aftercooler 4 to be cooled to 40 ℃, and then enters a hydrogenation separation tank 5 to be subjected to gas-liquid separation, the gas phase at the top of the hydrogenation separation tank 5 enters a compressor 9 through a compressor suction tank 8, most of the gas phase is returned to the hydrogenation reactor 1 as circulating hydrogen, and the purge gas 21 is released through a discharge pipeline to maintain the content of non-hydrogen gas in a circulating hydrogen system to be stable, and the bottom of the hydrogenation separation tank 5 is connected with a lightness-removing tower 11;
(c) Fresh hydrogen as hydrogenation supplementary hydrogen 24 is combined with gas at the top of a compressor suction tank 8 from the outside and enters a compressor 9, and the fresh hydrogen and unsaturated liquefied gas 20 enter a hydrogenation charging and discharging heat exchanger 2 together after being pressurized by the compressor 9;
(d) The material at the bottom of the hydrogenation separation tank 5 and the carbon four-saturated liquefied gas after the normalization reaction21 are mixed and enter a lightness-removing tower 11, and H is removed from the gas phase at the top of the tower through rectification separation 2 S，NH 3 The non-condensable gas is waited, the liquid phase removes light components such as carbon two, carbon three, etc., the bottom material and saturated carbon four 30 rich in normal/iso butane enter the normal butane finished product tower 14 together, the normal butane product 27 is obtained from the lateral line of the normal butane finished product tower 14 through rectification separation, the carbon five heavy components 28 are obtained from the tower kettle;
(e) Mixing a mixture rich in isobutane extracted from the top of a normal butane finished product tower 14 with fresh hydrogen outside, namely normalized supplemental hydrogen 22 and high-purity isobutane 29, heating to 160 ℃ through a normalized feed-discharge heat exchanger 17 and a first normalized feed heater 18A, then feeding into a first normalized reactor 19A, converting the isobutane into normal butane, discharging from the first normalized reactor 19A, heating to 160 ℃ through a second normalized feed heater 18B, and then feeding into a second normalized reactor 19B for continuous normalization;
(f) The carbon four material obtained from the second positive structure feed heater 19B after the positive structure reaction enters the light component eliminating tower 11 after heat exchange by the positive structure feed and discharge heat exchanger 17.
The method for producing the n-butane adopts the following process conditions:
the hydrogenation reactor 1 is a descending fixed bed reactor, the inlet temperature of the reactor is 240 ℃, the pressure is 3MPaG, the reaction temperature is 25 ℃, the hydrogen-oil molar ratio is 1.1, and the liquid volume space velocity is 2.0h -1 ；
The operating conditions of the light ends removal column 11 include: the pressure is 1.8MPaG, the operation temperature at the top of the tower is 50 ℃, and the number of tower plates is 80;
the operating conditions of the n-butane finishing tower 14 include: the pressure is 0.5MPaG, the operation temperature at the top of the tower is 45 ℃, and the number of tower plates is 130;
the two normal structure reactors are down-flow fixed bed reactors, the inlet temperature of the reactor is 160 ℃, the pressure is 3.3MPaG, the reaction temperature is 30 ℃, and the liquid volume space velocity is 10h -1 。
The results obtained by the above process are shown in table 4.
The results show that the device and the method of the embodiment are adopted to prepare the n-butane, the olefin content after hydrogenation is less than or equal to 1000ppm, the isobutane conversion rate in the normal structuring reaction is more than or equal to 50 percent, and the selectivity of the generated n-butane is more than or equal to 80 percent.
Table 4 example 4 material balance table
Figure BDA0002287797910000211
Figure BDA0002287797910000221
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims (8)

1. An apparatus for producing n-butane, characterized in that the apparatus comprises: the system comprises a light component removal tower, an n-butane finished product tower, a positive structured feeding and discharging heat exchanger, a positive structured feeding heater and a positive structured reaction unit; wherein, the first and the second end of the pipe are connected with each other,
the saturated liquefied gas feeding pipeline is connected with the light component removing tower;
a discharge pipeline at the bottom of the light component removal tower is connected with a normal butane finished product tower;
the top of the n-butane finished product tower is sequentially connected with a positive structure feeding and discharging heat exchanger and then connected with an inlet of a positive structure reaction unit; the outlet of the positive structure reaction unit is connected with a positive structure feeding and discharging heat exchanger and then connected with a lightness-removing tower; a side line of the n-butane finished product tower is connected with an n-butane product extraction pipeline;
the positive structure reaction unit comprises a single positive structure reactor or two positive structure reactors connected in series, and a positive structure feeding heater is arranged in front of each positive structure reactor;
the device is also provided with a saturated carbon four-feeding pipeline which is directly connected with a normal butane finished product tower and is rich in normal/iso-butane and a high-purity iso-butane feeding pipeline which is directly connected with a normal structured feeding and discharging heat exchanger;
the device also comprises a hydrogenation reactor, a hydrogenation feeding and discharging heat exchanger, a hydrogenation feeding heater and a hydrogenation separation device; wherein the content of the first and second substances,
the unsaturated liquefied gas feeding pipeline is connected with the hydrogenation feeding and discharging heat exchanger and the hydrogenation feeding heater and then is connected with the upper part of the hydrogenation reactor;
the bottom of the hydrogenation reactor is connected with a hydrogenation charging and discharging heat exchanger and then connected with a hydrogenation separation device, and the top of the hydrogenation separation device is sequentially connected with a compressor suction tank, a compressor and then combined with an unsaturated liquefied gas feeding pipeline and then connected with the hydrogenation charging and discharging heat exchanger;
the bottom of the hydrogenation separation device is connected with a light component removal tower.
2. An n-butane production apparatus according to claim 1, wherein the hydrogenation separation apparatus comprises a hydrogenation heat separation tank, a hydrogenation aftercooler and a hydrogenation cold separation tank; the bottom of the hydrogenation reactor is connected with a hydrogenation charging and discharging heat exchanger and then connected with a hydrogenation heat separation tank, the top of the hydrogenation heat separation tank is sequentially connected with a hydrogenation aftercooler and a hydrogenation cold separation tank, and the top of the hydrogenation cold separation tank is connected with a compressor suction tank; the bottom of the hydrogenation cold separation tank is connected with a hydrogenation hot separation tank; the bottom of the hydrogenation thermal separation tank is connected with a light component removal tower; alternatively, the first and second electrodes may be,
the hydrogenation separation device comprises a hydrogenation aftercooler and a hydrogenation separation tank; the bottom of the hydrogenation reactor is connected with a hydrogenation feeding and discharging heat exchanger and then sequentially connected with a hydrogenation aftercooler and a hydrogenation separation tank, the top of the hydrogenation separation tank is connected with a compressor suction tank, and the bottom of the hydrogenation separation tank is connected with a light component removal tower.
3. A method for producing n-butane using the apparatus of claim 1, wherein the method comprises at least one of the following three process sequences:
the process flow I:
(1) Saturated liquefied gas enters a lightness removing tower to remove light components and then enters an n-butane finished product tower, an n-butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the bottom of the tower, and C rich in isobutane is extracted from the top of the tower 4 Logistics;
(2) The above-mentionedC rich in isobutane 4 The material flow enters a positive structure reaction unit through a positive structure feeding and discharging heat exchanger to carry out positive structure reaction, and isobutane is converted into normal butane;
(3) After the positive structure reaction obtained by the positive structure reaction unit, the carbon four enters a lightness-removing tower after heat exchange by a positive structure feeding and discharging heat exchanger;
the process flow II comprises the following steps:
(1) Feeding saturated carbon IV rich in n/isobutane into a normal butane finished product tower, obtaining a normal butane product from a side line of the tower through rectification separation, obtaining a carbon five-component from a tower kettle, and extracting C rich in isobutane from the tower top 4 Logistics;
(2) Said isobutane rich C 4 The material flow enters a positive structure reaction unit through a positive structure feeding and discharging heat exchanger to carry out positive structure reaction, and isobutane is converted into normal butane;
(3) After the normalization reaction, the carbon IV enters a light component removal tower after heat exchange by a normalization feeding and discharging heat exchanger;
the process flow III:
(1) High-purity isobutane from the outside world is used as a normal feed and enters a normal reaction unit through a normal feeding and discharging heat exchanger to perform normal reaction, and the isobutane is converted into normal butane;
(2) After the positive structure reaction obtained by the positive structure reaction unit, the carbon four enters a lightness-removing tower after heat exchange by a positive structure feeding and discharging heat exchanger;
(3) The material flow at the bottom of the light component removal tower enters a normal butane finished product tower, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained at the bottom of the tower, and C rich in isobutane is extracted at the top of the tower 4 Logistics;
(4) Said isobutane rich C 4 The material flow enters a positive structure reaction unit for positive structure reaction after heat exchange through a positive structure feeding and discharging heat exchanger;
the process flow IV is as follows:
(a) Unsaturated liquefied gas from outside enters a hydrogenation reactor to hydrogenate and saturate olefins and remove impurities after heat exchange by a hydrogenation feeding and discharging heat exchanger;
(b) The bottom discharge of the hydrogenation reactor enters a hydrogenation separation device after passing through a hydrogenation feed-discharge heat exchanger, the separated hydrogen enters a compressor through a compressor suction tank and then returns to the hydrogenation reactor, and the bottom material of the hydrogenation separation device enters a lightness-removing tower;
(c) The bottom material of the light component removal tower enters a normal butane finished product tower, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the tower kettle, and C rich in isobutane is extracted from the tower top 4 Logistics;
(d) Said isobutane rich C 4 The material flow enters a positive structure reaction unit through a positive structure feeding and discharging heat exchanger to carry out positive structure reaction, and isobutane is converted into normal butane;
(e) And after the normalization reaction obtained by the normalization reaction unit, the carbon four is subjected to heat exchange by a normalization feeding and discharging heat exchanger and then enters the light component removal tower together with the material at the bottom of the hydrogenation separation device.
4. Method for the production of n-butane according to claim 3, comprising the steps of:
(i) The carbon four obtained after the normalization reaction of the saturated liquefied gas and the normalization reaction unit after heat exchange enters a lightness-removing tower, the light components are removed and then enter a normal butane finished product tower together with the saturated carbon four rich in normal/iso-butane, a normal butane product is obtained from the side line of the tower through rectification separation, a carbon five-component is obtained from the bottom of the tower, and the C rich in iso-butane is extracted from the top of the tower 4 Logistics;
(ii) Said isobutane rich C 4 After the material flow is mixed with high-purity isobutane coming from outside, the mixture enters a normal structure reaction unit through a normal structure feeding and discharging heat exchanger to carry out normal structure reaction, and the isobutane is converted into normal butane;
(iii) And after the normalization reaction obtained by the normalization reaction unit, the carbon four enters the lightness-removing tower after heat exchange by the normalization feeding and discharging heat exchanger.
5. The method for producing n-butane according to claim 3, wherein in the step (b), when the hydrogenation separation apparatus comprises a hydrogenation heat separation tank, a hydrogenation aftercooler and a hydrogenation cold separation tank, the bottom discharge of the hydrogenation reactor is cooled to 50 to 100 ℃ by a hydrogenation feed and discharge heat exchanger and then enters the hydrogenation heat separation tank, and the gas phase at the top of the hydrogenation heat separation tank is cooled to 20 to 50 ℃ by the hydrogenation aftercooler and then enters the hydrogenation cold separation tank.
6. The method for producing n-butane according to claim 3, wherein in the step (b), when the hydrogenation separation apparatus comprises a hydrogenation aftercooler and a hydrogenation separation tank, the bottom material of the hydrogenation reactor is cooled to 20 to 50 ℃ by the hydrogenation aftercooler after heat exchange by the hydrogenation charge-discharge heat exchanger, and then enters the hydrogenation separation tank.
7. The method for producing n-butane according to any one of claims 3 to 6, wherein,
the normal structuring reactor is a fixed bed reactor, and the operation conditions comprise: the inlet temperature of the reactor is 100-250 ℃, the pressure is 1.0-4.0 MPaG, and the liquid volume space velocity is 1-20 h -1 ；
The operating conditions of the light component removal tower comprise: the pressure is 1-3 MPaG, the operation temperature at the top of the tower is 30-90 ℃, and the number of tower plates is 30-150;
the operating conditions of the n-butane finished product tower comprise: the pressure is 0.1-1 MPaG, the operation temperature at the top of the tower is 20-70 ℃, and the number of tower plates is 50-150;
the saturated liquefied gas is a component rich in propane, isobutane, n-butane and a small amount of carbon two, carbon three and carbon five alkanes, wherein the content of olefin is less than 1wt%;
the saturated carbon four rich in n/isobutane is a stream rich in isobutane and n-butane, wherein the olefin content is less than 1wt%;
the high purity isobutane is a carbon-four stream with an isobutane content of greater than 90wt% and an olefin content of less than 1 wt%.
8. The method for producing n-butane according to any one of claims 3 to 6, wherein,
the hydrogenation reactor is a fixed bed reactor, and the operation conditions comprise: the inlet temperature of the reactor is 160-300 ℃, the pressure is 1.5-4.5 MPaG, the molar ratio of hydrogen to oil is 0.2-5, and the liquid volume space velocity is 0.5-6 h -1 ；
The unsaturated liquefied gas is at least one of oil field associated gas, gas field associated gas, refinery liquefied gas and ethylene plant ether post-carbon four, wherein the olefin content is 5-90 wt%.
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