CN112742309A

CN112742309A - Method for preparing high-octane gasoline

Info

Publication number: CN112742309A
Application number: CN201911053412.0A
Authority: CN
Inventors: 田雅楠; 师峰; 丁晖殿; 赵志海; 栗万博
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2021-05-04

Abstract

The invention relates to the field of hydrocarbon oil processing, and discloses a method for preparing high-octane gasoline, which comprises the following steps: pretreating an olefin raw material to obtain a treated material; introducing the treated materials into a polymerization reactor for reaction, and obtaining a reaction product material flow from an outlet of the polymerization reactor; the step of introducing the treated material into a polymerization reactor for reaction comprises the following steps: dividing the treated material into at least two streams, introducing a first stream into a polymerization reactor after exchanging heat with a reaction product stream so as to flow through a first catalyst bed layer; and respectively introducing the rest of the streams into the space between the catalyst bed layers of the superposed reactor, mixing with the product at the outlet of the previous catalyst bed layer, and then introducing the mixture into the next adjacent catalyst bed layer for reaction. The method of the invention does not have circulating materials any more, reduces equipment such as a flash evaporator, a carbon four condenser and the like, effectively reduces the size of the reactor and saves equipment investment.

Description

Method for preparing high-octane gasoline

Technical Field

The invention relates to the field of hydrocarbon oil processing, in particular to a method for preparing high-octane gasoline.

Background

With the implementation of the standards for full implementation of E10 ethanol gasoline, the automotive E10 ethanol gasoline standard GB18351-2017 specifies "ethanol volume fraction 10% ± 2%, no artificial addition of other organic oxygenates".

The limitation of the components of oxygenated gasoline has led to the increasing emphasis on the technology of blending-hydrogenation for producing gasoline with high octane number. In the non-selective polymerization reaction, the oligomerization conversion rate of the corresponding olefin in the four carbon components can reach more than 90 percent.

Since the reaction of the tetraolefin polymerization is an exothermic process and is typically a series-parallel reaction, the increase in temperature helps the reaction, but if the temperature is too high, the butene and its dimer undergo trimerization and high polymerization, and the selectivity of the dimer decreases.

Therefore, in the non-selective polymerization process, how to control the moderate reaction temperature rise and ensure the selectivity of the butene dimer is one of the very important subjects.

The UOP non-selective polymerization process is described in "development and comparison of polymerization process" by which a similar temperature rise of each layer of the catalyst is ensured by using alkane separated from a flash system after polymerization as a quenching oil [ petroleum refining, 1989(2):16-21 ]. But at the same time, the use of recycled material increases the reactor size and increases the equipment investment.

In addition, CN106084098A discloses a method for taking heat of butene-1 polymerization, which is a method for reducing the temperature of the material in the reaction kettle by using an external condenser, wherein the temperature of the butene-1 polymerization system is achieved by taking the steam material in the reaction kettle and sending the steam material into the condenser, cooling the steam material by using a refrigerant to take away the heat, and returning the condensate to the reaction kettle for continuous reaction.

And US14075012 discloses a combined olefin polymerization-hydrogenation process, which improves the selectivity of C8 polymerization product and effectively reduces the fouling of catalyst by recycling hydrogenated C8 alkane product as quench oil to the polymerization reactor.

However, the existing process has the defects of complex equipment and complicated flow.

Disclosure of Invention

The invention aims to overcome the defects of complex equipment and complicated flow in the non-selective laminating process in the prior art.

In order to achieve the above object, the present invention provides a method for preparing a high octane gasoline, comprising: pretreating an olefin raw material to obtain a treated material; introducing the treated material into a superposed reactor containing 3-15 catalyst beds for reaction, and obtaining a reaction product material flow from an outlet of the superposed reactor;

wherein the step of introducing the treated material into a polymerization reactor for reaction comprises: dividing the treated material into at least two streams, introducing a first stream into a polymerization reactor after exchanging heat with the reaction product stream so as to flow through a first catalyst bed layer of the polymerization reactor; introducing the rest of material flows into the space between the catalyst bed layers of the superposed reactor respectively, mixing the rest of material flows with a product at the outlet of the previous catalyst bed layer, and then introducing the mixture into the next adjacent catalyst bed layer for reaction;

the method further comprises the following steps: and separating the reaction product flow after heat exchange to obtain the laminated gasoline.

In the method, the progress of the superposition reaction is controlled by utilizing the operation mode that the reaction raw materials enter the reactor in a subsection mode, compared with the prior non-selective superposition process of UOP, the method has the advantages that no circulating material exists in the process, equipment such as a flash evaporator, a carbon four condenser and the like is reduced, the size of the reactor is effectively reduced, and the equipment investment is saved.

In addition, the method can also realize timely removal of heat released by olefin reaction and maintain stable temperature rise of the reaction bed layer.

Drawings

Fig. 1 is a preferred process flow diagram of the process for producing a high octane gasoline of the present invention.

Description of the reference numerals

28. Olefin feedstock

29. First stream of material

3. Pre-processing unit

31. Reaction product stream

32. Reaction product stream after heat exchange

33. Unreacted olefin feedstock

34. Superimposed gasoline

4. Heat exchanger

5. Polymerization reactor

6. Separation unit

30-2, second stream

30-N, Nth stream

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

As described above, the present invention provides a method for producing a high-octane gasoline, the method comprising: pretreating an olefin raw material to obtain a treated material; introducing the treated material into a superposed reactor containing 3-15 catalyst beds for reaction, and obtaining a reaction product material flow from an outlet of the superposed reactor;

The olefin raw material is preferably C3-C6 raw material containing olefin.

The invention preferably comprises 3-8 catalyst beds in the polymerization reactor.

According to a preferred embodiment, the remaining streams are introduced sequentially between the catalyst beds of the polymerization reactor, according to the flow direction of the liquid phase stream in the polymerization reactor. That is, the remaining streams are introduced into the polymerization reactor in the order of … … between the first catalyst bed, the second catalyst bed, and the third catalyst bed.

The invention does not intentionally require the introduction of the treated material between each catalyst bed layer, but in order to achieve better control of the polymerization progress, it is preferred that the introduction of the treated material between each catalyst bed layer is provided.

The pretreatment of the invention mainly comprises water washing, dealkalization nitrogen and purification treatment, and particularly preferably, the pretreatment operation ensures that the obtained treated material has an alkali nitrogen content of not more than 5ppm, a total metal content of not more than 5ppm and a butadiene content of not more than 500 ppm.

Preferably, the volume of each stream entering between the catalyst beds is controlled such that the temperature rise of each catalyst bed is in the range of 5 to 35 ℃. More preferably such that the temperature rise of each catalyst bed is in the range of 10 to 30 ℃.

Preferably, the mass fraction of the first material flow in the total reaction raw materials is 10-60%. The amount of the olefin in the raw material can be adjusted properly according to the content of the olefin in the raw material.

Preferably, the temperature in the polymerization reactor is 120-260 ℃.

Preferably, the pressure in the polymerization reactor is between 3.0 and 9.0 MPaG.

Preferably, the mass space velocity in the polymerization reactor is between 0.1 and 6h^-1。

Preferably, said separation of said reaction product stream after heat exchange is carried out in an apparatus comprising at least one rectification column.

The reaction product stream after heat exchange can also be separated to obtain unreacted olefin raw material.

Preferably, the olefin content of the olefin feed is in the range of from 15 to 50 wt%.

More preferably, the olefin in the olefin feedstock is selected from at least one of linear olefins having from 3 to 6 carbon atoms and isoolefins having from 3 to 6 carbon atoms.

The olefinic feedstock of the present invention may be, for example, an unseparated C3, C4 liquefied gas or a relatively single propylene or butene fraction.

The present invention does not require any particular kind of catalyst in the polymerization reactor, and various catalysts capable of performing polymerization conventionally used in the art may be used. The present invention is exemplified by specific catalyst types in the following examples, and those skilled in the art should not be construed as limiting the present invention.

A preferred embodiment of the process of the present invention is provided below in conjunction with the preferred process flow diagram of the process of the present invention for producing a high octane gasoline shown in fig. 1.

Specifically, in fig. 1, an olefin feedstock 28 enters a pretreatment unit 3 for pretreatment to obtain a treated material; introducing the treated materials into a polymerization reactor 5 containing 3-15 catalyst beds for reaction, and obtaining a reaction product material flow 31 from an outlet of the polymerization reactor 5;

wherein the step of introducing the treated material into the polymerization reactor 5 for reaction comprises: dividing the treated material into at least two streams, introducing a first stream 29 into a polymerization reactor 5 after exchanging heat with the reaction product stream 31 through a heat exchanger 4 so as to flow through a first catalyst bed layer of the polymerization reactor 5; introducing the rest of the streams into the space between the catalyst bed layers of the superposed reactor 5 respectively, mixing the streams with the product at the outlet of the previous catalyst bed layer, and then introducing the mixture into the next adjacent catalyst bed layer for reaction;

the method further comprises the following steps: the reaction product stream 32 after heat exchange is introduced into a separation unit 6 for separation to obtain an unreacted olefin feedstock 33 and a naphtha 34.

Further, in FIG. 1, for example, the treated material is divided into N streams, the second stream 30-2 enters between the first catalyst bed and the second catalyst bed, the second stream enters between the second catalyst bed and the third catalyst bed, and so on, the Nth stream 30-N enters between the (N-1) th catalyst bed and the Nth catalyst bed.

The method of the invention also has the following specific advantages:

(1) the process adopts a fixed bed polymerization reactor to carry out carbon tetraolefin polymerization to generate high-octane gasoline, adopts a raw material multi-stage feeding mode without circulating feeding, reduces the size of the reactor and reduces the equipment investment.

(2) Through the mode of multistage feeding, can effectual control reactant concentration, improve the selectivity of product.

(3) Through the multistage fixed bed feeding mode, can make full use of the reaction and release heat, effectively save the energy consumption of follow-up separation process.

The present invention will be described in detail below by way of examples. In the following examples, various raw materials used are commercially available ones unless otherwise specified.

The following examples, without being specifically illustrated, are carried out using the process flow shown in fig. 1, and the present invention is not described in detail in the following examples, which should not be construed as limiting the invention to those skilled in the art.

The polymerization reactors in the following examples all used the solid phosphoric acid catalyst RSPA-1.

Example 1

Example 1 high octane gasoline was prepared using a four-carbon olefin feed (feed 1800kg/h, detailed composition shown in table 1) using the equipment system and process shown in fig. 1, specifically:

pressurizing the four carbon components to 6.5MPaG, pretreating to obtain a treated material with 3ppm of alkali nitrogen, 2ppm of total metal and 123ppm of butadiene, dividing the treated material into 5 strands, and reacting in a polymerization reactor (the specific feeding distribution condition is shown in Table 2); the first material flow enters a fixed bed superposed reactor for reaction after heat exchange with the reaction product flow at the temperature of 160 ℃ and the reaction pressure of 6.25MPaG, and the reaction space velocity is 0.6h^-1The volume of each treated stream was controlled so that the bed temperature rise at each stage was controlled to 20 ℃.

Examples 2 and 3 the same raw materials, space velocity and reactor staging as in example 1 were used, the reaction temperature was varied, the reaction conditions for the metathesis reaction, the product distribution of the metathesis product as shown in tables 2 and 3, and the bed temperature rise per stage for examples 2 and 3 was controlled to 20 ℃.

Comparative example 1

The raw materials same as those in the example 1 are adopted to prepare the high-octane gasoline by a UOP non-selective superposition process flow, and the specific steps are as follows:

the raw material (the property is the same as that in the embodiment 1) after passing through the pretreatment unit is subjected to heat exchange with the product and steam heating, the temperature is raised to 180 ℃ required by the reaction, the reaction pressure is kept at 6.25MPaG, and the space velocity is 0.4h^-1(ii) a After the product and the raw materials are subjected to heat exchange and temperature reduction, evaporating unreacted tetracarbon components in a flash tank, liquefying the tetracarbon components by a carbon four condenser, pumping the tetracarbon components serving as quenching oil back to the space between the reactor beds, and keeping the temperature rise of each layer of the catalyst bed to be similar and 25 ℃; and (4) passing the heavy component after flash evaporation through a separation unit to obtain unreacted carbon four components and the superimposed gasoline. The reaction conditions and the product distribution of the polymerization are shown in Table 3.

As can be seen from the data in Table 3, in the method of the present invention, the selectivity of the carbon octamer product can be ensured even when the reaction space velocity is increased by 50%, the catalyst input and usage amount is effectively saved, the reactor size is reduced, the use of a series of equipment such as a flash tank, a flash tank condenser, a flash tank condensate tank and the like in the reaction product flash evaporation system is omitted, and the equipment investment and the energy consumption are reduced.

Under the same working condition, the energy consumption per unit of design of the comparative example 1 and the example 2 is respectively 13.1kg standard oil/t raw material and 8.7kg standard oil/t raw material, namely the energy consumption of the device can be effectively reduced by more than 33 percent.

Table 1: olefin feed compositions in examples 1-3

Name (R)	Composition, by weight%
		Three components of carbon	0.4
Isobutane	39.2
		N-butane	22.4
Isobutene	8.7
		N-butene	10.2
Butene of trans-butene	11.7
		N-butene	6.7
Carbon five	0.6

Table 2: carbon four feed split in examples 1-3

Table 3: the distribution of the products of the polymerization reaction in examples 1 to 3 and comparative example 1

Example 4

Example 4 high octane gasoline was prepared using an apparatus system and a process flow shown in fig. 1 using a four-carbon-component olefin feedstock (feed rate 1800kg/h, detailed composition contents are shown in table 4), the specific process flow was similar to example 1, the obtained treated feedstock had an alkali nitrogen content of 3ppm, a total metal content of 3ppm, and a butadiene content of 105ppm, the specific operating conditions of this example were as shown in tables 5 and 6, and the bed temperature rise in each stage was controlled at 23 ℃.

Example 5 and example 6 the same raw materials, reactor stages and space velocity as in example 4 were used, the reaction temperature was varied, and the bed temperature rise in each stage was controlled to 23 ℃, wherein the reaction conditions of the metathesis reaction and the product distribution of the metathesis product were as shown in table 6.

Comparative example 2

The same reaction raw materials as in example 4 are adopted to prepare high-octane gasoline by a UOP non-selective polymerization process flow, and the specific steps are as follows:

after the carbon four raw material (the property is the same as that in the embodiment 4), the raw material passes through the pretreatment unit, and then is subjected to heat exchange with the product and steam heating, so that the temperature is raised to 18 ℃ required by the reactionThe reaction pressure is kept at 6.25MPaG at 0 ℃, and the space velocity is 0.4h^-1(ii) a After the product and the raw materials are subjected to heat exchange and temperature reduction, evaporating unreacted tetracarbon components in a flash tank, liquefying the tetracarbon components by a carbon four condenser, pumping the tetracarbon components serving as quenching oil back to the space between the reactor beds, and keeping the temperature rise of each layer of the catalyst bed to be similar and 27 ℃; and (4) passing the heavy component after flash evaporation through a separation unit to obtain unreacted carbon four components and the superimposed gasoline. The reaction conditions and the product distribution of the polymerization are shown in Table 6.

As can be seen from the data in Table 6, in the method of the present invention, the selectivity of the carbon octamer product can be ensured even when the reaction space velocity is increased by 25%, the catalyst usage amount is effectively reduced, the reactor size is reduced, the use of equipment such as a flash tank, a flash tank condenser, a flash tank condensate tank in a reaction product flash evaporation system is omitted, and the equipment investment and energy consumption are reduced.

Under the same working condition, the energy consumption of the design units of the comparative example 2 and the example 5 are respectively 11.3kg standard oil/t raw material and 7.8kg standard oil/t raw material, namely the energy consumption of the device can be effectively reduced by more than 30 percent.

Table 4: olefin feed compositions in examples 4-6

Name (R)	Composition, by weight%
		Three components of carbon	0.4
Isobutane	45.1
		N-butane	12.1
Isobutene	8.8
		N-butene	10.7
Butene of trans-butene	13.3
		N-butene	9.6
Carbon five	0.6

Table 5: examples 4-6 carbon four feed distribution scenarios

Table 6: the distribution of the products of the superposition reactions in examples 4 to 6 and comparative example 2

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A process for producing a high octane gasoline, the process comprising: pretreating an olefin raw material to obtain a treated material; introducing the treated material into a superposed reactor containing 3-15 catalyst beds for reaction, and obtaining a reaction product material flow from an outlet of the superposed reactor;

2. The process as claimed in claim 1, wherein the remaining streams are introduced sequentially between the catalyst beds of the polymerization reactor in the direction of flow of the liquid phase stream in the polymerization reactor.

3. The method according to claim 1 or 2, wherein the pretreatment operation is carried out so that the treated material has an alkali nitrogen content of not more than 5ppm, a total metal content of not more than 5ppm and a butadiene content of not more than 500 ppm.

4. A process as claimed in any one of claims 1 to 3, wherein the volume of each stream entering between the catalyst beds is controlled such that the temperature rise of each catalyst bed is in the range 5 to 35 ℃;

preferably, the temperature rise of the respective catalyst bed is brought to 10-30 ℃.

5. The process as claimed in any one of claims 1 to 4, wherein the temperature in the polymerization reactor is 120-260 ℃.

6. The process according to any one of claims 1-5, wherein the pressure in the polymerization reactor is 3.0-9.0 MPaG.

7. Process according to any one of claims 1-6, wherein the mass space velocity in the polymerization reactor is between 0.1 and 6h^-1。

8. A process according to any one of claims 1 to 3, wherein the reaction product stream after heat exchange is subjected to said separation in an apparatus comprising at least one rectification column.

9. A process according to any one of claims 1 to 3, wherein the olefin content of the olefin feed is in the range of from 15 to 50 wt%.

10. The process of claim 9, wherein the olefins in the olefin feed are selected from at least one of linear olefins having from 3 to 6 carbon atoms and isoolefins having from 3 to 6 carbon atoms.