System and method for preparing propylene from isopropanol
阅读说明：本技术 一种异丙醇制丙烯的系统及方法 (System and method for preparing propylene from isopropanol ) 是由 李东风 廖丽华 李琰 罗淑娟 姜健准 李春芳 田峻 于 2020-04-15 设计创作，主要内容包括：本发明公开了一种异丙醇制丙烯的系统及方法。所述系统包括：异丙醇脱水反应器、水洗塔、碱洗塔、脱轻塔或脱重塔、丙烯塔；异丙醇脱水反应器底部连接水洗塔,水洗塔顶部连接碱洗塔,碱洗塔顶部连接脱轻塔或脱重塔,脱轻塔或脱重塔连接丙烯塔。采用本发明的系统和方法,可以得到纯度为99.9％的丙烯。得到的丙烯可以用作聚丙烯、丙烯腈、氧化丙烯、乙烯-丙烯橡胶等合成的反应物,本发明具有工艺简单、丙烯纯度高、回收率高等优点。(The invention discloses a system and a method for preparing propylene from isopropanol. The system comprises: an isopropanol dehydration reactor, a water washing tower, an alkaline washing tower, a light component removal tower or a heavy component removal tower and a propylene tower; the bottom of the isopropanol dehydration reactor is connected with a water washing tower, the top of the water washing tower is connected with an alkaline washing tower, the top of the alkaline washing tower is connected with a light component removal tower or a heavy component removal tower, and the light component removal tower or the heavy component removal tower is connected with a propylene tower. By adopting the system and the method, the propylene with the purity of 99.9 percent can be obtained. The obtained propylene can be used as a reactant for synthesizing polypropylene, acrylonitrile, propylene oxide, ethylene-propylene rubber and the like, and the method has the advantages of simple process, high propylene purity, high recovery rate and the like.)
1. A system for preparing propylene from isopropanol is characterized by comprising: an isopropanol dehydration reactor, a water washing tower, an alkaline washing tower, a light component removal tower or a heavy component removal tower and a propylene tower;
the bottom of the isopropanol dehydration reactor is connected with a water washing tower, the top of the water washing tower is connected with an alkaline washing tower, the top of the alkaline washing tower is connected with a light component removal tower or a heavy component removal tower, and the light component removal tower or the heavy component removal tower is connected with a propylene tower.
2. The system for producing propylene from isopropanol according to claim 1, wherein:
the top of the water washing tower is connected with a compressor and then connected with an alkaline washing tower; and/or the presence of a gas in the gas,
the top of the alkaline washing tower is connected with a compressor and then is connected with a light component removal tower or a heavy component removal tower.
3. The system for producing propylene from isopropanol according to claim 1, wherein:
the bottom of the light component removal tower is connected with a propylene tower.
4. The system for producing propylene from isopropanol according to claim 1, wherein:
the top of the de-heavy column is connected with a propylene column.
5. A process for producing propylene from isopropanol using the system of any of claims 1 to 4, wherein the process comprises:
(a) dehydrating isopropanol to obtain crude propylene;
(b) feeding the crude propylene into a water washing tower to remove most of water and aldehyde generated in the reaction;
(c) sending the top material flow of the water washing tower into an alkaline washing tower to remove acid components;
(d) sending the material flow at the top of the alkaline washing tower into a light component removing tower or a heavy component removing tower,
(e) and (3) feeding the material flow at the bottom of the light component removal tower or the material flow at the top of the heavy component removal tower into a propylene tower to obtain high-purity propylene.
6. The process for producing propylene from isopropanol according to claim 5, wherein:
in the step (c), the overhead stream of the water washing tower is compressed to 0.5-1.5 MPaG and then sent to an alkali washing tower to remove acid components.
7. The process for producing propylene from isopropanol according to claim 5, wherein:
and (d) compressing the material flow on the top of the alkaline washing tower to 1.5-3.0 MPaG, and then sending the material flow into a light component removal tower or a heavy component removal tower.
8. The process for producing propylene from isopropanol according to claim 5, wherein:
step (a), the reaction temperature is 100-450 ℃, and preferably 200-350 ℃; and/or the presence of a gas in the gas,
the reaction pressure is 0.01 to 0.1 MPaG.
9. The process for producing propylene from isopropanol according to claim 5, wherein:
step (d), the material flow at the top of the alkaline washing tower is sent to a light component removal tower, a small amount of light components are removed from the top of the light component removal tower, and the produced liquid at the tower kettle of the light component removal tower is sent to a propylene tower;
the operation temperature of the top of the light component removal tower is 2-30 ℃;
the operation temperature of a tower kettle of the light component removal tower is 20-80 ℃;
the operating pressure of the light component removal tower is 1.0-3.0 MPaG;
the number of theoretical plates of the light component removal tower is 20-70; and/or the presence of a gas in the gas,
removing heavy components from the tower kettle of the propylene tower, and obtaining high-purity propylene from the tower top of the propylene tower;
the operation temperature of the top of the propylene tower is 20-60 ℃;
the operation temperature of a tower kettle of the propylene tower is 50-100 ℃;
the operating pressure of the propylene tower is 1.5-3.0 MPaG;
the number of theoretical plates of the propylene tower is 30-100.
10. The process for producing propylene from isopropanol according to claim 9, wherein:
the operation temperature of the top of the light component removal tower is 5-25 ℃;
the operation temperature of a tower kettle of the light component removal tower is 30-70 ℃;
the operating pressure of the light component removal tower is 1.5-2.7 MPaG;
the number of theoretical plates of the light component removal tower is 30-60; and/or the presence of a gas in the gas,
the operation temperature of the top of the propylene tower is 30-50 ℃;
the operation temperature of a tower kettle of the propylene tower is 60-90 ℃;
the operating pressure of the propylene tower is 1.7-2.5 MPaG;
the number of theoretical plates of the propylene tower is 40-80.
11. The process for producing propylene from isopropanol according to claim 5, wherein:
step (d), the material flow at the top of the alkaline washing tower is sent to a de-heavy tower, a small amount of heavy components are removed at the tower bottom of the de-heavy tower, and the produced liquid at the tower top of the de-heavy tower is sent to a propylene tower;
the operation temperature of the top of the de-heavy tower is 5-50 ℃;
the operation temperature of a tower kettle of the de-weighting tower is 60-120 ℃;
the operating pressure of the de-heavy tower is 1.8-2.8 MPaG;
the number of theoretical plates of the de-weighting tower is 20-50; and/or the presence of a gas in the gas,
removing light components from the top of the propylene tower, and obtaining high-purity propylene at the bottom of the propylene tower;
the operation temperature of the top of the propylene tower is 5-60 ℃;
the operation temperature of a tower kettle of the propylene tower is 50-100 ℃;
the operating pressure of the propylene tower is 2-4.5 MPaG;
the number of theoretical plates of the propylene tower is 20-60.
12. The process for producing propylene from isopropanol according to claim 11, wherein:
the operation temperature of the top of the de-heavy tower is 20-45 ℃;
the operation temperature of a tower kettle of the de-weighting tower is 70-100 ℃;
the operating pressure of the de-heavy tower is 2.0-2.5 MPaG;
the number of theoretical plates of the de-weighting tower is 25-45; and/or the presence of a gas in the gas,
the operation temperature of the top of the propylene tower is 10-50 ℃;
the operation temperature of a tower kettle of the propylene tower is 60-80 ℃;
the operating pressure of the propylene tower is 2.5-3.5 MPaG;
the number of theoretical plates of the propylene tower is 25-50.
Technical Field
The invention relates to the technical field of propylene, and further relates to a system and a method for preparing propylene from isopropanol.
Background
In recent years, China has a strong demand for propylene, and propylene recovery in ethylene plants and refineries is a main source of propylene.
Acetone is produced as a byproduct in the process of preparing phenol by an isopropyl benzene method, and with the rapid development of the domestic phenol market and the wide use of the technology for preparing phenol by the isopropyl benzene method, the demand is basically balanced, so that a large amount of acetone growing faces to the continuous market and is low. In addition, acetone may also be produced or by-produced by a number of chemical processes. In order to use acetone efficiently, it is desirable to develop a route for converting acetone into isopropanol and dehydrating the isopropanol to propylene.
The domestic production scale of phenol prepared by the cumene method is large, the propylene can be recycled by using the isopropanol dehydration and separation as a matching technology of the phenol preparation process by the cumene method, so that the propylene does not need to be supplemented or is supplemented less in the cumene method process, the operation cost is reduced, and the benefit is remarkable.
At present, the research and development of catalysts aiming at preparing propylene by dehydrating isopropanol and the research on the process are few at home and abroad. Only the Mitsui company of Japan develops a process for directly preparing propylene by dehydrating isopropanol, and the process is also a matched technology for the propylene recycling application of the process for preparing phenol by an isopropyl benzene method. The materials after the isopropanol dehydration reaction are recycled, the processes of dehydration, alkali washing, light and heavy removal and a propylene rectifying tower are omitted, the propylene is not purified, and the aim is not to obtain the high-purity propylene.
Chinese patent CN108530257A relates to a method for co-producing cumene and propylene by benzene and isopropanol, which comprises the steps of contacting benzene and isopropanol with a molecular sieve catalyst to synthesize cumene and propylene under effective reaction conditions; the effective reaction conditions include at least: the molar ratio of benzene to isopropanol is in the range of greater than 0 to less than 2. The method can be used for the industrial production of coproducing cumene and propylene.
Chinese patent CN103508833A provides a method for preparing propylene by dehydration of isopropanol, which comprises: contacting isopropanol with a catalyst under isopropanol dehydration reaction conditions to dehydrate the isopropanol to produce propylene, wherein the catalyst is produced by a process comprising the steps of: preparing a gel system containing a template agent and an aluminum source; then removing the solvent in the gel system and roasting to obtain mesoporous nano alumina; wherein the template agent is block copolyether shown as a formula (1); wherein R1 is an amino-substituted hydrocarbyl group, and x, y and z are each independently 1 to 100; the aluminum source is organic aluminum salt.
CN1025182C relates to the production of propylene in high yield and selectivity by dehydration of isopropanol in the presence of a gamma-alumina catalyst with an average pore diameter of 30 to 150 and a standard deviation (σ n) of 10 to 40, based on statistical calculations of pore diameter and micropore volume.
The above patents do not relate to systems and processes. Related process research and patents are not reported in China.
Some similar processes are known for the production of olefins. For example, ethylene from ethanol and isobutylene from tert-butanol. However, these methods cannot be used for producing propylene from isopropanol.
Therefore, the development of a system for preparing propylene from isopropanol is a technical problem to be solved urgently at present.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a system and a method for preparing propylene from isopropanol. The obtained propylene can be used as a reactant for synthesizing polypropylene, acrylonitrile, propylene oxide, ethylene-propylene rubber and the like, and has the advantages of simple process, high propylene purity, high recovery rate and the like.
The invention aims to provide a system for preparing propylene from isopropanol.
The method comprises the following steps:
an isopropanol dehydration reactor, a water washing tower, an alkaline washing tower, a light component removal tower or a heavy component removal tower and a propylene tower;
the bottom of the isopropanol dehydration reactor is connected with a water washing tower, the top of the water washing tower is connected with an alkaline washing tower, the top of the alkaline washing tower is connected with a light component removal tower or a heavy component removal tower, and the light component removal tower or the heavy component removal tower is connected with a propylene tower.
In a preferred embodiment of the present invention,
a compressor is arranged between the water washing tower and the alkaline washing tower; the top of the water washing tower is connected with a compressor and then connected with an alkaline washing tower;
in a preferred embodiment of the present invention,
a compressor is arranged between the alkaline washing tower and the light component removing tower or the heavy component removing tower.
The top of the alkaline washing tower is connected with a compressor and then is connected with a light component removal tower or a heavy component removal tower.
When the light component removal tower is adopted, the bottom of the light component removal tower is connected with a propylene tower.
When the heavy component removing tower is adopted, the top of the heavy component removing tower is connected with a propylene tower.
The second purpose of the invention is to provide a method for preparing propylene from isopropanol.
The method comprises the following steps:
the method comprises the following steps:
(a) dehydrating isopropanol to obtain crude propylene;
(b) feeding the crude propylene into a water washing tower to remove most of water and aldehyde generated in the reaction;
(c) sending the top material flow of the water washing tower into an alkaline washing tower to remove acid components;
(d) sending the material flow at the top of the alkaline washing tower into a light component removing tower or a heavy component removing tower,
(e) and (3) feeding the material flow at the bottom of the light component removal tower or the material flow at the top of the heavy component removal tower into a propylene tower to obtain high-purity propylene.
Wherein the content of the first and second substances,
in step (a), the dehydration of isopropanol to give propylene may be carried out using an acidic compound as a catalyst, for example, mineral acid, sulfuric acid, phosphoric acid, hydrochloric acid, nitric acid; halogen peroxides, such as perchloric acid, perbromic acid, periodic acid; solid acidic materials such as silica, silica-alumina, alumina-gamma alumina, zeolites, molecular sieves, and metal oxides such as titania, zinc oxide, zirconia. The dehydration of isopropanol may be carried out in the gas phase or in the liquid phase. The reaction temperature is in the range of 100-450 ℃, and the preferable range is 200-350 ℃. The reaction pressure is 0.01 to 0.1 MPaG.
When a solid catalyst is used, the reactor may be a tubular fixed bed reactor or a multistage adiabatic fixed bed reactor or a fluidized bed, and a fixed bed reactor is preferably used. The reaction product mainly contains components such as propylene, water, isopropanol, propane, propionaldehyde, acetone, diisopropyl ether and the like.
In the step (b), most of the heavy components such as water and aldehyde generated in the reaction can be removed in a water washing tower;
in the step (c), the overhead stream of the water washing tower is compressed to 0.5-1.5 MPaG and then sent to an alkaline washing tower to remove acid components; the acidic component refers to an acidic component comprising CO2, sulfide and the like;
and (d) compressing the material flow on the top of the alkaline washing tower to 1.5-3.0 MPaG, and then sending the material flow into a light component removal tower or a heavy component removal tower.
The dehydrated and compressed reaction product (crude propylene) goes to a rectification unit. The crude propylene mainly contains components such as propylene, isopropanol, propane, diisopropyl ether and the like. (rectification units refer to light ends removal column/heavy ends removal column and propylene column).
When the light component removing tower is arranged as the light component removing tower,
step (d), the material flow at the top of the alkaline washing tower is sent to a light component removal tower, a small amount of light components are removed from the top of the light component removal tower, and the produced liquid at the tower kettle of the light component removal tower is sent to a propylene tower; the light components mainly comprise hydrogen, methane, carbon monoxide and the like;
the operation temperature of the top of the light component removal tower is 2-30 ℃;
the operation temperature of a tower kettle of the light component removal tower is 20-80 ℃;
the operating pressure of the light component removal tower is 1.0-3.0 MPaG;
the number of theoretical plates of the light component removal tower is 20-70;
the preferable technological conditions of the light component removal tower are as follows:
the operation temperature of the top of the light component removal tower is 5-25 ℃;
the operation temperature of a tower kettle of the light component removal tower is 30-70 ℃;
the operating pressure of the light component removal tower is 1.5-2.7 MPaG;
the number of theoretical plates of the light component removal tower is 30-60;
removing heavy components from the tower kettle of the propylene tower, and obtaining high-purity propylene from the tower top of the propylene tower; the heavy components mainly comprise components such as propane, isopropanol, diisopropyl ether, water and the like.
The operation temperature of the top of the propylene tower is 20-60 ℃;
the operation temperature of a tower kettle of the propylene tower is 50-100 ℃;
the operating pressure of the propylene tower is 1.5-3.0 MPaG;
the number of theoretical plates of the propylene tower is 30-100;
the preferred process conditions for the propylene column are:
the operation temperature of the top of the propylene tower is 30-50 ℃;
the operation temperature of a tower kettle of the propylene tower is 60-90 ℃;
the operating pressure of the propylene tower is 1.7-2.5 MPaG;
the number of theoretical plates of the propylene tower is 40-80.
When the heavy component removing tower is arranged as the heavy component removing tower,
step (d), the material flow at the top of the alkaline washing tower is sent to a de-heavy tower, a small amount of heavy components are removed at the tower bottom of the de-heavy tower, and the produced liquid at the tower top of the de-heavy tower is sent to a propylene tower; the heavy components mainly comprise components such as propane, isopropanol, diisopropyl ether, water and the like;
the operation temperature of the top of the de-heavy tower is 5-50 ℃;
the operation temperature of a tower kettle of the de-weighting tower is 60-120 ℃;
the operating pressure of the de-heavy tower is 1.8-2.8 MPaG;
the number of theoretical plates of the de-weighting tower is 20-50;
the preferable technological conditions of the heavy component removing tower are as follows:
the operation temperature of the top of the de-heavy tower is 20-45 ℃;
the operation temperature of a tower kettle of the de-weighting tower is 70-100 ℃;
the operating pressure of the de-heavy tower is 2.0-2.5 MPaG;
the number of theoretical plates of the de-weighting tower is 25-45;
removing light components from the top of the propylene tower, and obtaining high-purity propylene at the bottom of the propylene tower; the light components mainly comprise hydrogen, methane, carbon monoxide and the like.
The operation temperature of the top of the propylene tower is 5-60 ℃;
the operation temperature of a tower kettle of the propylene tower is 50-100 ℃;
the operating pressure of the propylene tower is 2-4.5 MPaG;
the number of theoretical plates of the propylene tower is 20-60.
The preferred process conditions for the propylene column are:
the operation temperature of the top of the propylene tower is 10-50 ℃;
the operation temperature of a tower kettle of the propylene tower is 60-80 ℃;
the operating pressure of the propylene tower is 2.5-3.5 MPaG;
the number of theoretical plates of the propylene tower is 25-50.
By adopting the system and the method, the propylene with the purity of 99.9 percent can be obtained. The obtained propylene can be used as a reactant for synthesizing polypropylene, acrylonitrile, propylene oxide, ethylene-propylene rubber and the like, and the method has the advantages of simple process, high propylene purity, high recovery rate and the like.
Drawings
FIG. 1 is a schematic view of a system for producing propylene from isopropanol in example 1;
FIG. 2 is a schematic view of a system for producing propylene from isopropanol in example 2;
description of reference numerals:
1, isopropyl alcohol; 2 an isopropanol dehydration reactor; 3, reaction products; 4, washing the tower with water; 5, water;
8, a compressor; 10, an alkaline washing tower; 11, alkali liquor; 14, a compressor B; 18 a de-weighting tower; 16 light component removal tower;
17 light component; 19 a propylene column; 20 a propylene product; 21 heavy fraction.
Fig. 1 shows a light component removal column, and the system for producing propylene from isopropyl alcohol in fig. 1 includes: an isopropanol dehydration reactor 2, a water washing tower 4, an alkaline washing tower 10, a light component removal tower 16 and a propylene tower 19; the bottom of the isopropanol dehydration reactor 2 is connected with a water scrubber 4, the top of the water scrubber 4 is connected with a compressor 8 and then connected with an alkaline washing tower 10, the top of the alkaline washing tower 10 is connected with a compressor B14 and then connected with a light component removal tower 16, and the bottom of the light component removal tower 16 is connected with a propylene tower 19.
The process of fig. 1 includes:
the isopropanol 1 enters an isopropanol dehydration reactor 2, the reaction operation temperature is 220 ℃, and the operation pressure is 0.03 MPaG; dehydrating the isopropanol to generate propylene and other small-amount byproducts;
the reaction product 3 enters the bottom of a water washing tower 4, water 5 is sprayed from the top of the tower, and heavy components such as water, aldehyde and the like are removed from the tower kettle in the water washing tower 4;
the pressure of the water-washed overhead gas phase material is increased to 0.8MpaG in the compressor 8.
After pressurization, crude propylene enters the bottom of an alkaline washing tower 10, NaOH alkaline liquor 11 enters from the top of the tower, and acidic substances such as CO2, H2S and the like are removed by the NaOH alkaline liquor;
the crude propylene from which the acidic substances were removed was further pressurized to 2.7MPaG in compressor B14;
and then sent to the lightness-removing column 16. Removing light components such as hydrogen, methane, CO and the like at the top of the light component removing tower, and sending the produced liquid at the tower bottom to a propylene tower 19;
the heavy components 21 such as propane, isopropanol, diisopropyl ether, water and the like are removed from the bottom of the propylene tower, and propylene 20 with the purity of 99.92 percent is obtained from the top of the tower.
Fig. 2 uses a de-weighting column. The system for preparing propylene from isopropanol in fig. 2 comprises: an isopropanol dehydration reactor 2, a water washing tower 4, an alkaline washing tower 10, a heavy component removal tower 18 and a propylene tower 19; the bottom of the isopropanol dehydration reactor 2 is connected with a water scrubber 4, the top of the water scrubber 4 is connected with a compressor 8 and then connected with an alkaline washing tower 10, the top of the alkaline washing tower 10 is connected with a compressor B14 and then connected with a de-heavy tower 18, and the top of the de-heavy tower 18 is connected with a propylene tower 19.
The process of fig. 2 includes:
the isopropanol 1 enters an isopropanol dehydration reactor 2, and the reaction operation temperature is 330 ℃, and the operation pressure is 0.08 MPaG. Dehydrating the isopropanol to generate propylene and other small-amount byproducts;
the reaction product 3 enters the bottom of a water washing tower 4, water 5 is sprayed from the top of the tower, and heavy components such as water, aldehyde and the like are removed from the tower kettle in the water washing tower 4.
The pressure of the water-washed overhead gas phase feed is increased to 1.4MpaG in compressor 8.
After pressurization, crude propylene enters the bottom of an alkaline washing tower 10, NaOH alkaline liquor 11 enters from the top of the tower, and CO is converted into CO by the NaOH alkaline liquor2、H2And removing acidic substances such as S and the like.
The crude propylene freed of sour species is further pressurized in compressor B14 to 2.1 MPaG. And then to de-heaving column 18.
Removing heavy components such as propane, isopropanol, diisopropyl ether, water and the like in the kettle of the heavy component removal tower, and sending the produced liquid at the tower top to the propylene tower 19.
Light components 20 such as hydrogen, methane, CO and the like are removed from the top of the propylene tower, and a propylene product 20 with the purity of 99.99 percent is obtained from the bottom of the tower.
Detailed Description
While the present invention will be described in detail and with reference to the specific embodiments thereof, it should be understood that the following detailed description is only for illustrative purposes and is not intended to limit the scope of the present invention, as those skilled in the art will appreciate numerous insubstantial modifications and variations therefrom.
Example 1
As shown in FIG. 1, a system for producing propylene from isopropanol. The method comprises the following steps: an isopropanol dehydration reactor 2, a water washing tower 4, an alkaline washing tower 10, a light component removal tower 16 and a propylene tower 19; the bottom of the isopropanol dehydration reactor 2 is connected with a water scrubber 4, the top of the water scrubber 4 is connected with a compressor 8 and then connected with an alkaline washing tower 10, the top of the alkaline washing tower 10 is connected with a compressor B14 and then connected with a light component removal tower 16, and the bottom of the light component removal tower 16 is connected with a propylene tower 19.
The method comprises the following steps:
the isopropanol 1 enters an isopropanol dehydration reactor 2, the reaction operation temperature is 220 ℃, and the operation pressure is 0.03 MPaG. Dehydrating the isopropanol to generate propylene and other small-amount byproducts;
the reaction product 3 enters the bottom of a water washing tower 4, water 5 is sprayed from the top of the tower, and heavy components such as water, aldehyde and the like are removed from the tower kettle in the water washing tower 4;
the pressure of the water-washed overhead gas phase material is increased to 0.8MpaG in the compressor 8.
After pressurization, crude propylene enters the bottom of an alkaline washing tower 10, NaOH alkaline liquor 11 enters from the top of the tower, and acidic substances such as CO2, H2S and the like are removed by the NaOH alkaline liquor;
the crude propylene from which the acidic substances were removed was further pressurized to 2.7MPaG in compressor B14;
and then sent to the lightness-removing column 16. Removing light components such as hydrogen, methane, CO and the like at the top of the light component removing tower, and sending the produced liquid at the tower bottom to a propylene tower 19;
the operating pressure of the light component removal tower is 2.6MPaG, the tower top temperature is 15 ℃, the tower bottom temperature is 65 ℃, and the theoretical plate number is 50.
The heavy components 21 such as propane, isopropanol, diisopropyl ether, water and the like are removed from the bottom of the propylene tower, and propylene 20 with the purity of 99.92 percent is obtained from the top of the tower.
The operating pressure of the propylene tower is 2.0MPaG, the tower top temperature is 40 ℃, the tower kettle temperature is 85 ℃, and the theoretical plate number is 80.
The compositions of the light component 17, the heavy component 21 and the propylene product 20 obtained by the reaction and separation system of the isopropanol 1 are shown in Table 1.
TABLE 1 composition of system for dehydrating isopropanol to propylene
The component mol%
Isopropanol 1
Light fraction 17
Heavy fraction 21
Propylene product 20
Isopropanol (I-propanol)
96.64
23.85
Acetone (II)
0.90
30.25
Diisopropyl ether
0.045
2.82
Methyl isobutyl carbinol
0.03
0.587
Propane
0.014
0.002
0.009
0.015
Water (W)
1.071
18.503
Hydrogen gas
1.199
70.113
Methane
0.099
1.984
0.069
Propylene (PA)
27.901
23.978
99.92
Kmol/h
114.36
2.0
1.85
110.52
In this example, the propylene recovery was 99.1%.
Example 2
As shown in FIG. 2, a system for producing propylene from isopropanol. The method comprises the following steps: an isopropanol dehydration reactor 2, a water washing tower 4, an alkaline washing tower 10, a heavy component removal tower 18 and a propylene tower 19; the bottom of the isopropanol dehydration reactor 2 is connected with a water scrubber 4, the top of the water scrubber 4 is connected with a compressor 8 and then connected with an alkaline washing tower 10, the top of the alkaline washing tower 10 is connected with a compressor B14 and then connected with a de-heavy tower 18, and the top of the de-heavy tower 18 is connected with a propylene tower 19.
The method comprises the following steps:
the isopropanol 1 enters an isopropanol dehydration reactor 2, and the reaction operation temperature is 330 ℃, and the operation pressure is 0.08 MPaG. Dehydrating the isopropanol to generate propylene and other small-amount byproducts;
the reaction product 3 enters the bottom of a water washing tower 4, water 5 is sprayed from the top of the tower, and heavy components such as water, aldehyde and the like are removed from the tower kettle in the water washing tower 4.
The pressure of the water-washed overhead gas phase feed is increased to 1.4MpaG in compressor 8.
After pressurization, crude propylene enters the bottom of an alkaline washing tower 10, NaOH alkaline liquor 11 enters from the top of the tower, and CO is converted into CO by the NaOH alkaline liquor2、H2And removing acidic substances such as S and the like.
The crude propylene freed of sour species is further pressurized in compressor B14 to 2.1 MPaG. And then to de-heaving column 18.
Removing heavy components such as propane, isopropanol, diisopropyl ether, water and the like in the kettle of the heavy component removal tower, and sending the produced liquid at the tower top to the propylene tower 19.
The operating pressure of the heavy component removal tower is 2.0MPaG, the tower top temperature is 40 ℃, the tower bottom temperature is 95 ℃, and the theoretical plate number is 50.
Light components 20 such as hydrogen, methane, CO and the like are removed from the top of the propylene tower, and a propylene product 20 with the purity of 99.986 percent is obtained from the bottom of the tower.
The operating pressure of the propylene tower is 2.8MPaG, the tower top temperature is 16 ℃, the tower bottom temperature is 66 ℃, and the theoretical plate number is 50.
The compositions of the heavy component 21, the light component 17 and the propylene product 20 obtained by the reaction and separation system of the isopropanol 1 are shown in Table 2.
TABLE 2 composition of the system for producing propylene by dehydration of isopropanol
The component mol%
Isopropanol 1
Light fraction 17
Heavy fraction 21
Propylene product 20
Isopropanol (I-propanol)
96.64
23.814
Acetone (II)
0.90
30.213
Diisopropyl ether
0.045
2.82
Methyl isobutyl carbinol
0.03
0.586
Propane
0.014
0.001
0.022
0.014
Water (W)
1.071
18.478
Hydrogen gas
1.199
63.439
Methane
0.099
5.228
Propylene (PA)
31.33
24.066
99.986
Kmol/h
114.36
2.21
1.85
110.30
In this example, the propylene recovery was 99.0%.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：基于氯铝酸离子液体催化的萘低聚物的制备方法