阅读说明：本技术 由混合碳四原料生产1-丁烯的方法 (Method for producing 1-butene from mixed C4 raw material ) 是由 卢和泮 杨卫胜 刘俊涛 于 2019-10-25 设计创作，主要内容包括：本发明公开了一种由混合碳四原料生产1-丁烯的方法,包括如下步骤：S1.对混合碳四原料进行预处理,分别得到含异丁烯和1-丁烯的碳四物流I以及含2-丁烯的重质碳四物流II；S2.对所述含2-丁烯的重质碳四物流II进行异构化处理,得到富含1-丁烯的碳四物流III；S5.对所述富含1-丁烯的碳四物流III进行分离处理,分别得到1-丁烯产品以及2-丁烯产品；S6.任选地,将步骤S5得到的2-丁烯循环回步骤S2中进行异构化处理。该方法可以达到最终1-丁烯产品中异丁烯和丁二烯满足下游使用要求的目标。(The invention discloses a method for producing 1-butene by using mixed C4 raw materials, which comprises the following steps: s1, pretreating a mixed C-C raw material to respectively obtain a C-C four material flow I containing isobutene and 1-butene and a heavy C-C four material flow II containing 2-butene; s2, carrying out isomerization treatment on the heavy carbon four material flow II containing 2-butene to obtain a carbon four material flow III rich in 1-butene; s5, separating the C-IV stream III rich in 1-butene to respectively obtain a 1-butene product and a 2-butene product; s6, optionally, recycling the 2-butene obtained in the step S5 to the step S2 for isomerization treatment. The method can achieve the aim that isobutene and butadiene in the final 1-butene product meet the downstream use requirements.)

1. A method for producing 1-butene from mixed C4 raw materials comprises the following steps:

s1, pretreating a mixed C-C raw material to respectively obtain a C-C four material flow I containing isobutene and 1-butene and a heavy C-C four material flow II containing 2-butene;

s2, carrying out isomerization treatment on the heavy carbon four material flow II containing 2-butene to obtain a carbon four material flow III rich in 1-butene;

s5, separating the C-IV stream III rich in 1-butene to respectively obtain a 1-butene product and a 2-butene product;

s6, optionally, recycling the 2-butene obtained in the step S5 to the step S2 for isomerization treatment.

2. The method of claim 1, wherein the mixed carbon four feedstock comprises, in weight percent: (a)10 to 35 percent of 1-butene, (b)50 to 80 percent of 2-butene, (c) 1, 3-butadiene less than or equal to 3 percent, and (d)0.5 to 8 percent of isobutene.

3. The method of claim 1 or 2, wherein the mixed C-C feedstock is pretreated in step S1 in a pretreatment column to obtain a C-C four stream I containing isobutene and 1-butene at the top of the pretreatment column and a heavy C-C four stream II containing 2-butene at the bottom of the pretreatment column.

4. The method according to any one of claims 1 to 3, wherein the number of theoretical plates of the pretreatment column is 50 to 200 layers, preferably 100 to 200 layers, more preferably 130 to 200 layers; and/or the recovery rate of the 2-butene in the tower bottom of the pretreatment tower is more than or equal to 60 percent, preferably more than or equal to 70 percent, more preferably more than or equal to 80 percent, and most preferably more than or equal to 90 percent; the isobutene content of the heavy C.sub.four stream II containing 2-butenes is preferably < 0.12% by weight.

5. The process according to any of claims 1 to 4, characterized in that the heavy tetracarbonate stream II containing 2-butene is subjected to an isomerization treatment in step S2 to isomerize 2-butene into 1-butene; preferably, the reaction temperature in the step S2 is 250-350 ℃, the reaction pressure is 0-2 MPa, and the reaction weight space velocity is 2-10 h^-1The selectivity of isobutene generated by 2-butene is less than or equal to 0.1 percent, and the selectivity of 1-butene generated by 2-butene is more than or equal to 14 percent.

6. The method according to any one of claims 1-5, characterized in that the method further comprises the steps of:

and S3, carrying out hydrogenation treatment on the C-IV stream III rich in 1-butene to obtain a hydrogenated material.

7. The method of claim 6, wherein the ratio of (1-butene flow in hydrogenated material)/(butadiene flow in hydrogenated material) > 3350 in step S3; and/or a 1-butene loss in the hydrotreatment of 8% or less, preferably 5% or less, more preferably 3% or less.

8. The method according to any one of claims 1-7, characterized in that the method further comprises the steps of:

s4, the hydrogenated material enters a light component removal tower for light component removal treatment, a material flow containing a component with a boiling point lower than 1-butene is obtained at the tower top, and a carbon four material flow III' rich in 1-butene is obtained at the tower bottom;

the 1-butene-rich C-IV stream III' enters the separation process of step S5 to obtain a 1-butene product and a 2-butene product.

9. The method according to claim 8, wherein the recovery rate of 1-butene in the bottom of the light ends removal tower is more than or equal to 5%, preferably more than or equal to 3%, and more preferably more than or equal to 1%; and/or the content of light components in the tower bottom, which are lighter than isobutane, is less than or equal to 1 wt%, preferably less than or equal to 0.5 wt%, and more preferably less than or equal to 0.1 wt%.

10. The process according to any one of claims 1 to 9, wherein the 1-butene-rich carbon tetrad stream III is treated in step S5 in a 1-butene product tower to obtain 1-butene product at the top of the tower and 2-butene product at the bottom of the tower; preferably, the 1-butene product tower has 100-200 theoretical plates; and/or the tower pressure of the 1-butene product is 0.3-0.5 MPa; and/or the purity of the 1-butene at the tower top of the 1-butene product tower is more than or equal to 99.0 wt%.

Technical Field

The invention relates to a method for producing 1-butene from a mixed C4 raw material, in particular to a method for producing 1-butene from a coal-based mixed C4 raw material.

Background

1-butene is an important alpha-olefin. High purity 1-butene is mainly used as a comonomer for the production of linear low density polyethylene. One polyethylene plant tends to produce both high density and low density polyethylene from the viewpoint of improving product competitiveness, and thus a certain amount of 1-butene is inevitably used. In addition, other oligomerization products of the 1-butene can be widely used for automobile and lubricating oil additives, synthetic detergents, surfactants, plasticizers, printing dyes, emulsifiers and the like. In the art, 1-butene is spoken in close proximity to isobutene, and thus the literature in the art sometimes refers to 1-butene as butene-1.

Some production methods of 1-butene can be classified into 2 general types: a hybrid C4 separation process and a chemical synthesis process (ethylene dimerization process). The related field of the invention is the separation method of mixed C4, so the invention is only explained for the related documents of the mixed C4 field. The biggest difficulty of the production scheme is in the separation of 1-butene and isobutene, the boiling point difference of the two substances is very close and cannot be removed by rectification, and the isobutene is removed by extraction or reaction in the known methods.

The separation process of mixed C4 is reviewed in the literature "1-butene production Process and its general application":

at present, the production of 1-butene in China is mainly based on a mixed C4 separation method, and mixed C4 is mainly from a steam cracking device, a catalytic cracking (FCC) device and a coal-to-olefin (MTO) device in the petrochemical industry. Although the mixed C4 byproduct in petrochemical and coal chemical industries is different in components, the mixed C4 byproduct contains a large amount of 1-butene, and also contains components such as butane, butadiene, 2-butene, isobutene and the like. The following technologies are mainly available at home and abroad:

1.1 extractive distillation technique

Krupp Uhde, Germany, has a great deal of experience in aromatic extractive distillation and has developed an advanced extractive distillation technology capable of separating n-butene (1-butene, 2-butene) and butane. The technology adopts the mixture of morpholine and N-formyl morpholine as an extracting agent, has higher selectivity, solubility, chemical stability and thermal stability, can simply and effectively separate N-butene from butane, has a separation effect far exceeding that of traditional extracting agents such as DMF (dimethyl formamide), acetonitrile and the like, and does not generate phenomena such as condensation polymerization, glue formation and the like, thereby reducing the consumption of the extracting agent and improving the utilization rate of the extracting agent. The extractive distillation process flow of Krupp uhde company is that firstly, the raw material containing mixed C4 is sent to an extractive distillation tower, and an extractant containing n-butene (butane and other low-carbon olefins at the tower top) is obtained at the tower bottom through the extraction process. And secondly, sending the n-butene to a stripping tower, and separating the n-butene from the extracting agent by adopting common rectification to obtain the n-butene with the purity of about 97 percent. Finally, if 1-butene is further obtained, 2-butene in the n-butene can be isomerized by adopting a catalytic isomerization method, and finally the l-butene product is obtained.

1.2 Rui Weng (Zeon) method

The Ruizian (Zeon) method (GPD process) is a process that Ruizian company takes GPB process (process for producing butadiene) as the basis, and further transforms l, 3-butadiene and isobutene are removed from mixed C4 fraction by adopting polar solvent, and then 1-butene is further separated. The polar solvent adopted by the process has good solubility and relative volatility superior to other solvents. The process flow is shown in figure 1. The mixture C4 firstly enters a first extractive distillation tower and is separated by extractive distillation, and the mixture of the butene and the solvent is at the bottom of the tower (the butane is at the top of the tower). And the butene and the solvent from the bottom of the first extractive distillation tower enter a first solvent recovery tower again for butene and solvent separation. The butene is distilled out from the top of the first solvent recovery tower and enters a first rectifying tower to separate out the 2-butene. And performing 2 nd extraction and rectification on the residual materials to obtain a 1-butene product.

1.3 NPC Process

The NPC method of the Japanese petrochemical company is mainly used for separating l-butene from a mixed C4 fraction which is a byproduct of an ethylene plant. The process comprises the steps of firstly extracting butadiene by using an extractive distillation device, and then removing isobutene in raffinate by an MTBE method. Secondly, the etherified mixed C4 is hydrogenated and dimerized to remove butadiene and isobutene separately. Finally, the l-butene with the purity of more than 99 percent is obtained by super rectification. However, since the relative volatility of 1-butene and n-butane is only 1.10 and the theoretical plate number of the rectifying tower is 140, the energy consumption is large. The process flow and part of the process parameters are shown in figure 2.

1.4 UOP Process technology

The UOP company also uses a process in which, first, mixed C4 is etherified and then. The method for producing the l-butene combines a FLEX process (used for adsorbing and separating olefin and alkane) and a butene isomerization process. The yield of the 1-butene product by the process can reach 90 percent, and the process flow is shown in figure 3.

1.5 other domestic technological techniques

With the continuous progress of chemical technology in China, various domestic research institutes also propose a process for producing l-butene by separating and mixing C4. These processes are basically a chemical reaction to remove butadiene and isobutylene from mixed C4, and then separate and produce l-butene, such as the extractive distillation process of the tobacco institute of university and the two-stage distillation process of the zilu petrochemical industry. These processes have their own advantages depending on the source of the hybrid C4, and have already been put into commercial use. The C4 separation method has rich raw material resources, low price and low product cost.

In the 5 technical routes mentioned in the above documents, butadiene and isobutylene need to be removed by extractive distillation or reactive distillation, which all have the problems of long process and high investment.

The document "discussion of utilization of coal-based mixed carbon four" refers to a method for producing 1-butene by using coal-based mixed carbon four:

firstly removing dimethyl ether and carbon five heavy components from the mixed carbon four, adsorbing and removing oxides, then removing 1, 3-butadiene through selective hydrogenation, and sending the mixture into a catalytic rectification unit to remove isobutene and isobutane; the removed material is sent into a butene rectification system, and 1-butene (polymerization grade), 2-butene and butane are separated in the butene rectification system; the 2-butene is sent into an isomerization unit, converted into 1-butene through isomerization, and then sent back to a butene rectification system to separate the 1-butene. Or 1-butene and 2-butene obtained from a butene rectification system can be sent into a butene transposition unit in proportion, ethylene, propylene and hexene-3 are obtained through transposition treatment, and the ethylene, the propylene and the hexene-3 are separated through a separation system; the hexene-3 is converted into hexene-1 through isomerization, and polymerization-grade hexene-1 and part of tail gas are obtained by a rectification method. The flow is shown in fig. 4.

The method reported in the document is more similar to the field of the invention, but the process is more complex than the invention, the method needs to additionally remove oxygen-containing compounds and heavy components, and simultaneously, the method inevitably adopts a selective hydrogenation method to remove 1, 3-butadiene and a catalytic distillation method to remove isobutene, so that the process is long and the investment is high.

Patent CN 101928195a reports a process for producing 1-butene, characterized by comprising the following steps: 1) selective hydrogenation; 2) etherification; 3) carrying out catalytic rectification; 4) washing and recovering the methanol; 5) and (3) refining the 1-butene. The technical route of the invention still adopts selective hydrogenation to remove 1, 3-butadiene, and uses an MTBE device to remove isobutene, and the process is long and the investment is high.

The removal of 1-butene, 1, 3-butadiene and isobutene produced by mixing C4 is a problem that cannot be circumvented by the above documents and published techniques, which report the removal of 1, 3-butadiene by extraction or selective hydrogenation and the removal of isobutene by MTBE in most cases. The coal-based mixed carbon four raw material is characterized in that: the content of isobutene and butadiene is low, according to the traditional technical route, the scale of an MTBE device built for removing isobutene is small, but some reaction rectification processes are required to be available, the process is long, and the investment is high. Under the current national policy of pushing ethanol gasoline, the living space of MTBE is more squeezed, the possibility that the production of 1-butene is influenced due to the difficulty of MTBE sale can appear, and 1-butene is often just needed for standard coal chemical industry such as MTO device of 180 ten thousand tons/year, the reason is that the downstream ethylene matching device is mostly LLDPE, and the consumption of 1-butene is about 10% of the yield of LLDPE.

Disclosure of Invention

The invention aims to solve the technical problems of long process, high investment and marketing problem that a byproduct MTBE is influenced by national policy when coal-based mixed C4 is used as a raw material to produce 1-butene, and provides a novel method for producing 1-butene from coal-based mixed C4. The method is characterized in that according to the characteristics of coal-based carbon four: the method has the advantages of low content of isobutene and butadiene and high content of 2-butene, controls the isobutene in the 2-butene in a range without influencing the quality of 1-butene products by using a precise pretreatment method, can convert the 2-butene into the 1-butene with high selectivity by using butene isomerization, and can achieve the aim that the isobutene and the butadiene in the final 1-butene products meet the downstream use requirements by using the characteristic of almost no byproduct isobutene. For some materials with lower butadiene content, the invention can meet the production requirement even without selective hydrogenation when processing some raw materials, and the principle is that butadiene is more active and is easy to polymerize at some suitable condition positions in the process flow, such as higher temperature positions, and simultaneously 1-butene and butadiene still have certain boiling point difference, and butadiene can be removed to a certain extent as long as a light removal flow exists. The method has the characteristics of short flow, low investment and strong competitiveness.

In order to achieve the aim of the invention, the invention provides a method for producing 1-butene by mixing four carbon materials, which comprises the following steps:

s1, pretreating a mixed C-C raw material to respectively obtain a C-C four material flow I containing isobutene and 1-butene and a heavy C-C four material flow II containing 2-butene;

s2, carrying out isomerization treatment on the heavy carbon four material flow II containing 2-butene to obtain a carbon four material flow III rich in 1-butene;

s5, separating the C-IV stream III rich in 1-butene to respectively obtain a 1-butene product and a 2-butene product;

s6, optionally, recycling the 2-butene obtained in the step S5 to the step S2 for isomerization treatment.

According to some embodiments of the invention, the mixed carbon four feedstock is a coal-based mixed carbon four feedstock.

According to a preferred embodiment of the invention, the mixed carbon four raw material comprises the following components in percentage by weight: (a)10 to 35 percent of 1-butene, (b)50 to 80 percent of 2-butene, (c) 1, 3-butadiene less than or equal to 3 percent, and (d)0.5 to 8 percent of isobutene.

According to some embodiments of the invention, the mixed C-C feedstock is pretreated in step S1 in a pretreatment column to obtain a C-C four stream I containing isobutene and 1-butene at the top of the column and a heavy C-C four stream II containing 2-butene at the bottom of the column.

According to a preferred embodiment of the present invention, the number of theoretical plates of the pretreatment column is 50 to 200 layers, preferably 100 to 200 layers, and more preferably 130 to 200 layers.

According to a preferred embodiment of the invention, the recovery rate of 2-butene in the tower bottom of the pretreatment tower is more than or equal to 60%, preferably more than or equal to 70%, more preferably more than or equal to 80%, and most preferably more than or equal to 90%.

According to a preferred embodiment of the invention, the isobutene content of the heavy C2-butene-containing stream II is preferably ≦ 0.12 wt%

According to some embodiments of the invention, the heavy tetracarbon stream II containing 2-butene is subjected to an isomerization treatment in step S2 to isomerize 2-butene to 1-butene.

According to the preferred embodiment of the present invention, the reaction temperature in step S2 is 250-350 ℃, the reaction pressure is 0-2 MPa, and the reaction weight space velocity is 2-10 h^-1The selectivity of isobutene generated by 2-butene is less than or equal to 0.1 percent, and the selectivity of 1-butene generated by 2-butene is more than or equal to 14 percent.

According to a preferred embodiment of the invention, the heavy tetracarbon stream II containing 2-butene is subjected to an isomerization treatment in an isomerization unit in step S2, obtaining a tetracarbon stream III enriched in 1-butene.

According to a preferred embodiment of the invention, the 1-butene-rich carbonium tetrastream III has a 1-butene content of > 12%. According to a preferred embodiment of the invention, the method further comprises the steps of:

s3, carrying out hydrogenation treatment on the C-IV stream III rich in 1-butene to obtain a hydrogenated material,

according to a preferred embodiment of the present invention, the ratio of (1-butene flow in hydrogenated material)/(butadiene flow in hydrogenated material) in step S3 is > 3350.

According to a preferred embodiment of the invention, the 1-butene loss in the hydrotreatment is less than or equal to 8%, preferably less than or equal to 5%, more preferably less than or equal to 3%.

According to a preferred embodiment of the invention, the method further comprises the steps of:

s4, the hydrogenated material enters a light component removal tower for light component removal treatment, a material flow containing a component with a boiling point lower than 1-butene is obtained at the tower top, and a carbon four material flow III' rich in 1-butene is obtained at the tower bottom;

the 1-butene-rich C-IV stream III' enters the separation process of step S5 to obtain a 1-butene product and a 2-butene product.

According to the preferred embodiment of the invention, the recovery rate of 1-butene in the tower bottom of the light component removal tower is more than or equal to 5 percent, preferably more than or equal to 3 percent, and more preferably more than or equal to 1 percent.

According to a preferred embodiment of the invention, the content of light components in the column bottom lighter than isobutane is less than or equal to 1 wt%, preferably less than or equal to 0.5 wt%, more preferably less than or equal to 0.1 wt%.

According to a preferred embodiment of the invention, the 1-butene-rich carbon tetrad stream III is treated in step S5 in a 1-butene product tower, wherein 1-butene product is obtained at the top of the tower and 2-butene product is obtained at the bottom of the tower.

According to a preferred embodiment of the invention, the 1-butene product column has 100 to 200 theoretical plates; and/or the tower pressure of the 1-butene product is 0.3-0.5 Mpa.

According to the preferred embodiment of the invention, the purity of the 1-butene at the top of the 1-butene product tower is more than or equal to 99.0 wt%.

According to a preferred embodiment of the invention, the 1-butene recovery from the top of the 1-butene product column is 60% or more, preferably 70% or more, more preferably 80% or more, and most preferably 90% or more.

In the above description, in a scenario where a column is used to separate certain materials, the recovery rate is defined as the mass percentage of a certain target material in the stream of material to the total amount of all target materials entering the column.

Drawings

FIG. 1 is a process flow diagram of the Rueisen (Zeon) process;

FIG. 2 is a process flow diagram of the NPC process;

FIG. 3 is a flow chart of UOP Process technology;

FIG. 4 is a flow chart of a process for producing 1-butene from coal-based C.sub.C. according to the discussion on utilization of C.sub.C. for coal-to-olefin;

FIG. 5 is a process flow diagram of a method for producing 1-butene from a mixed C4 feedstock according to one embodiment of the present invention;

FIG. 6 is a process flow diagram of a method for producing 1-butene from a mixed C4 feedstock according to another embodiment of the present invention;

FIG. 7 is a process flow diagram of a comparative example for producing 1-butene using a conventional process flow;

description of reference numerals: 1 is a mixed C-C raw material, 2 is a C-C material flow I, 3 is a C-C material flow II, 4 is a C-C material flow III, 5 is a 1-butene product, 6 is a 2-butene product, 7 is 2-butene which is recycled to an isomerization unit, 8 is a light component removal tower feeding material, 9 is a light component removal tower top discharging material, 10 is a light component removal tower bottom discharging material, 12 is a C-C material flow which is subjected to selective hydrogenation to remove butadiene, and 13 is a Methyl Tert Butyl Ether (MTBE) product; 1 'is a first extractive distillation column, 2' is a first solvent recovery column, 3 'is a first distillation column, 4' is a second extractive distillation column, 5 'is a second solvent recovery column, and 6' is a second distillation column.

Detailed Description

The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention in any way.

FIG. 5 shows a process flow diagram of a method for producing 1-butene from a mixed C.sub.four feedstock in accordance with one embodiment of the present invention. Sending the mixed C-C raw material (1) to a pretreatment tower for pretreatment, obtaining a light C-C four stream I (2) at the tower top, obtaining a heavy C-C four stream II (3) with very low butadiene and isobutene contents at the tower bottom, enabling the C-C four stream II (3) to enter an isomerization unit for reaction to generate a C-C four stream III (4), enabling the C-C four stream III (4) to enter a 1-butene product tower, obtaining a 1-butene product (5) at the tower top, obtaining a 2-butene product (6) at the tower bottom, and recycling part of the 2-butene product (7) to the isomerization unit.

FIG. 6 shows a process flow diagram of a method for producing 1-butene from a mixed C.sub.four feedstock according to another embodiment of the present invention. Sending the mixed C-C raw material (1) to a pretreatment tower for pretreatment, obtaining a light C-C flow I (2) at the tower top, obtaining a heavy C-C flow II (3) with very low butadiene and isobutene contents at the tower bottom, sending the C-C flow II (3) into an isomerization unit for reaction to generate a C-C flow III (4), sending the C-C flow III (4) into a hydrogenation unit to obtain a hydrogenated material (8), sending the hydrogenated material (8) into a light-component removal tower to obtain a flow 9 at the tower top, obtaining a flow 10 at the tower bottom, sending the flow 10 into a 1-butene product tower, obtaining a 1-butene product (5) at the tower top, obtaining a 2-butene product (6) at the.

FIG. 7 shows a process flow diagram of a comparative example of the present invention, which is a conventional 1-butene production scheme. The method comprises the steps of carrying out selective hydrogenation unit reaction on a mixed C-C four raw material (1), sending a C-C four material flow 12 with butadiene removed to an MTBE unit for isobutene removal treatment, obtaining a C-C four material flow (8) with isobutene removed at the top of a tower, obtaining a material flow (9) at the top of the tower after the material (8) enters a lightness removing tower, obtaining a material flow (10) at the bottom of the tower, entering the material flow (10) into a 1-butene product tower, obtaining a 1-butene product (5) at the top of the tower, and obtaining a 2-butene product (6) at.

[ example 1 ]

By adopting the flow shown in fig. 5, the material flow 1 is mixed carbon four, and the composition in percentage by weight is as follows: 27% 1-butene; 61% 2-butene; 0.001% 1, 3-butadiene; 4.5% of isobutene; the remainder was a butane component, the flow rate of which was 1000 kg/h. And (3) sending the material flow 1 into a pretreatment tower, wherein the theoretical number of trays of the pretreatment tower is 130, under the condition of a reflux ratio of 12.4, the material flow 2 is extracted from the top of the pretreatment tower, the flow is 338kg/h, the material flow 3 rich in 2-butene is obtained from the bottom of the pretreatment tower, the flow is 662kg/h, the isobutene flow is 0.6kg/h, the 2-butene flow is 592kg/h, and the butadiene flow is 0.002 kg/h.

And (3) feeding the material flow 3 into an isomerization unit, obtaining a material flow 4 at 280 ℃, 0.5MPaG (propylene glycol) pressure and 6h-1 airspeed, wherein the material flow 4 contains 14 wt% of 1-butene and 0.11% of isobutene, and after the material flow 4 enters a product tower, the material flow is separated at the tower top to obtain a 1-butene product, the flow rate is 85kg/h, the content of 1-butene is 99%, the content of isobutene is 0.78 wt%, and the content of butadiene is 0.011 wt%. The flow of stream 7 was 0 kg/h.

[ example 2 ]

By adopting the flow shown in fig. 5, the material flow 1 is mixed carbon four, and the composition in percentage by weight is as follows: 27% 1-butene; 61% 2-butene; 0.001% 1, 3-butadiene; 4.5% of isobutene; the remainder was a butane component, the flow rate of which was 1000 kg/h. And (3) sending the material flow 1 into a pretreatment tower, wherein the theoretical number of trays of the pretreatment tower is 130, under the condition of a reflux ratio of 12.4, the material flow 2 is extracted from the top of the pretreatment tower, the flow is 338kg/h, the material flow 3 rich in 2-butene is obtained from the bottom of the pretreatment tower, the flow is 662kg/h, the isobutene flow is 0.6kg/h, the 2-butene flow is 592kg/h, and the butadiene flow is 0.002 kg/h.

And (3) feeding the material flow 3 into an isomerization unit, obtaining a material flow 4 at 280 ℃, 0.5MPaG (propylene glycol) pressure and 6h-1 airspeed, wherein the material flow 4 contains 14 wt% of 1-butene and 0.11% of isobutene, and after the material flow 4 enters a product tower, the material flow is separated at the top of the tower to obtain a 1-butene product, the flow rate is 97kg/h, the content of 1-butene is 99%, the content of isobutene is 0.78 wt%, and the content of butadiene is 0.011 wt%. The flow rate of stream 7 was 155 kg/h.

[ example 3 ]

By adopting the flow shown in fig. 6, the material flow 1 is mixed carbon four, and the composition in percentage by weight is as follows: 27% 1-butene; 61% 2-butene; 1.5% 1, 3-butadiene; 4.5% of isobutene; the remainder was a butane component, the flow rate of which was 1000 kg/h. And (3) sending the material flow 1 into a pretreatment tower, wherein the theoretical number of trays of the pretreatment tower is 200 layers, under the condition of a reflux ratio of 16, the material flow 2 is extracted from the top of the pretreatment tower, the flow rate is 365kg/h, the material flow 3 rich in 2-butene is obtained from the bottom of the pretreatment tower, the flow rate is 635kg/h, the isobutene flow rate is 0.001kg/h, the butadiene flow rate is 0.035kg/h, and the content of the 2-butene is 589 kg/h.

Feeding the material flow 3 into an isomerization unit, obtaining a material flow 4 when the pressure is 0.55MPaG and the space velocity is 5h < -1 > at 300 ℃, wherein the material flow 4 contains 15 wt% of 1-butene, 0.02 wt% of isobutene and 0.007 wt% of butadiene, the material flow 4 enters a selective hydrogenation unit to obtain a hydrogenation reaction product material flow 8, the content of 1-butene is 14.6%, the content of butadiene is 0.0018 wt%, the content of isobutene is kept unchanged, the material flow 8 enters a lightness removing tower to obtain a tower top material flow 9 with the flow rate of 15kg/h, a tower bottom material flow 10 is also obtained, the material flow 10 is fed into a product tower, and the tower top is separated to obtain a 1-butene product material flow 5 with the flow rate of 239kg/h, the content of 1-butene is 99.3%, the content of isobutene is 0.15% and the content of butadiene is 0.012 wt%. The product column bottom recycle stream 7 was 879 kg/h.

Comparative example 1

The flow shown in fig. 7 is adopted, and the material flow 1 is a mixed carbon four raw material, and comprises the following components in percentage by weight: 27% 1-butene; 61% 2-butene; 1.5% 1, 3-butadiene; 4.5% of isobutene; the remainder was a butane component, the flow rate of which was 1000 kg/h. Feeding stream 1 to a selective hydrogenation unit to obtain stream 4 having a composition of 25% 1-butene; 74% 2-butene; 0.00002% 1, 3-butadiene; 4.5% of isobutene; the remainder being the butane component. And (3) sending the material flow 4 and corresponding methanol to be consumed into an MTBE unit to obtain a mixed carbon four material flow 8 after isobutene removal, wherein the flow rate of the mixed carbon four material flow is 945kg/h, an MTBE product (material flow 13, the flow rate of the mixed carbon four material flow is 123kg/h), sending the mixed carbon four material flow into a lightness-removing tower to obtain a tower top material flow 9, the flow rate of the tower top material flow is 35kg/h, and also obtaining a tower bottom material flow 10, sending the material flow 10 into a product tower, and separating the tower top to obtain a 1-butene product material flow 5, wherein the flow rate of the 1-butene product flow is 230kg/h, the 1-butene content is 99.3%, the isobutene.

Compared with the examples, the 1-butene obtained in the comparative example has to produce a part of MTBE, 123kg/h in the comparative example; furthermore, the 1-butene production is limited by the content in the feed and the hydroisomerization loss in the selective hydrogenation, which is less than in example 3.

Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.