CN-121974772-A - Method and device for preparing low-carbon olefin

CN121974772ACN 121974772 ACN121974772 ACN 121974772ACN-121974772-A

Abstract

The application relates to a method and a device for preparing low-carbon olefin, wherein the method comprises the steps of S1, enabling an ether raw material to contact a catalytic conversion catalyst in a catalytic conversion reactor to carry out catalytic conversion reaction to obtain a catalytic conversion reaction product, and S2, separating the catalytic conversion reaction product to obtain ethylene and propylene. The method can realize the conversion of ethers into low-carbon olefin, improve the yield and selectivity of ethylene and propylene, reduce the yield of methane, simultaneously reduce the content of methanol in the product to the maximum extent, realize the conversion of low-cost methanol into low-carbon olefin, improve the selectivity and yield of low-carbon olefin, obviously reduce the yield of methane in dry gas, and have better economic and social benefits.

Inventors

BAI XUHUI
SHA YOUXIN
WANG XIN
WANG QIFEI
WANG RUILIN

Assignees

中国石油化工股份有限公司
中石化石油化工科学研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20241030

Claims (11)

1. A method of making a lower olefin comprising: S1, enabling an ether raw material to be in contact with a catalytic conversion catalyst in a catalytic conversion reactor for catalytic conversion reaction to obtain a catalytic conversion reaction product, wherein the ether raw material has a structural formula of C n H 2n+1 -O-C m H 2m+1 , and m and n are each independently integers greater than or equal to 1, preferably 1-10, more preferably 1-6, and most preferably 1-4; S2, separating the catalytic conversion reaction product to obtain ethylene and propylene.
2. The process of claim 1, wherein separating the catalytic conversion reaction product further yields a first recycle olefin stream comprising butenes and/or a second recycle olefin stream comprising C 5 + olefins; The method further comprises the steps of: S3, enabling at least one part of the first circulating olefin flow and/or at least one part of the second circulating olefin flow to enter an etherification unit together with optional external source olefin, and enabling the first circulating olefin flow and/or at least one part of the second circulating olefin flow to contact with an alcohol raw material under etherification conditions to obtain circulating ether materials and ether-post-olefin; s4, recycling the recycled ether material and the optional olefin after ether back to the catalytic conversion reactor for catalytic conversion reaction.
3. The process of claim 1, wherein the ether feedstock is selected from one or more of methyl tertiary butyl ether, methyl tertiary amyl ether, methyl tertiary hexyl ether, methyl tertiary heptyl ether, methyl sec-butyl ether, methyl sec-amyl ether, methyl sec-hexyl ether, methyl sec-heptyl ether, ethyl tertiary butyl ether, ethyl tertiary amyl ether, ethyl tertiary hexyl ether, ethyl tertiary heptyl ether, ethyl sec-butyl ether, ethyl sec-amyl ether, ethyl sec-hexyl ether, ethyl sec-heptyl ether, dimethyl ether, methyl diethyl ether, preferably the ether feedstock is from an etherification unit selected from methyl tertiary butyl ether unit, light gasoline etherification unit, ethyl tertiary butyl ether unit, and combinations thereof.
4. The process according to claim 1, wherein the reaction temperature of the catalytic conversion reaction is about 460-750 ℃, preferably about 500-700 ℃, more preferably about 520-700 ℃, most preferably about 550-680 ℃.
5. The process of claim 1, wherein the catalytic conversion reaction has a reaction time of about 0.01 to 15 seconds, preferably about 0.05 to 10 seconds, more preferably about 0.1 to 8.0 seconds, most preferably about 0.15 to 7.0 seconds, and a catalyst to oil weight ratio of about 1 to 50, preferably about 5 to 40, more preferably about 6 to 30.
6. The method according to claim 1, wherein the alcohol source is selected from one or more of methanol, ethanol, propanol, butanol, pentanol, preferably the alcohol source is selected from methanol, ethanol or a combination thereof.
7. The process according to claim 1, wherein the etherification conditions comprise a reaction temperature of about 20-120 ℃, preferably about 30-80 ℃, more preferably about 35-75 ℃, a reaction pressure of 0-5.0MPa, preferably 0.2-2.0MPa, more preferably 0.5-1.5MPa.
8. The process of claim 1, wherein the catalytic conversion catalyst is selected from amorphous silica alumina catalysts and/or zeolite catalysts, the zeolite in the zeolite catalysts being selected from the group consisting of Y-series zeolite catalysts, beta-series zeolite molecular sieves, ZSM-series molecular sieve catalysts, SAPO-series molecular sieves.
9. The process according to claim 8, wherein the catalytic conversion catalyst is selected from the group consisting of ZSM-type series of molecular sieves, preferably from the group consisting of ZSM-5, ZSM-11 molecular sieves and hierarchical pore molecular sieves, wherein the molecular sieves have a molar ratio SiO 2 /AlO 3 of from 50 to 1000, preferably from 80 to 800, most preferably from 100 to 800.
10. The process of claim 8 wherein the catalytic conversion catalyst is a high silica zeolite containing phosphorus and transition metals having a anhydrous chemical formula of (0-0.3)Na 2 O·(0.3-5)Al 2 O 3 ·(1-10)P 2 O 5 ·(0.7-20)M x O y ·(70-95)SiO 2 , on a mass basis of oxides wherein element M is selected from one or more of rare earth elements, alkali and alkaline earth metals, fe, co, ni, cu, zn, mo and Mn, x is the valence of oxygen, and y is the valence of element M.
11. An apparatus for producing light olefins comprising: a catalytic conversion reactor for bringing the ether raw material into contact with a catalytic conversion catalyst in the catalytic conversion reactor to perform a catalytic conversion reaction to obtain a catalytic conversion reaction product; A separation unit connected to the catalytic conversion reactor such that catalytic conversion reaction products from the catalytic conversion reactor are fed into the separation unit for separating the catalytic conversion reaction products to obtain ethylene and propylene, and a first recycle olefin stream comprising butenes and/or a second recycle olefin stream comprising C 5 + olefins; The etherification unit is connected with the separation unit, so that at least a part of the first circulating olefin flow and/or the second circulating olefin flow and optional external source olefin enter the etherification unit to be contacted with the alcohol raw material under the etherification condition to obtain circulating ether materials and ether post-olefin; Wherein the etherification unit is also connected with the catalytic conversion reactor and is used for recycling the cyclic ether material and the optional olefin after ether back to the catalytic conversion reactor for catalytic conversion reaction.

Description

Method and device for preparing low-carbon olefin Technical Field The application relates to the field of preparation of low-carbon olefins, in particular to a method and a device for catalytically converting an ether compound into low-carbon olefins. Background Along with the rapid development of national economy, the environmental pollution problem is more and more important for people, the environmental protection regulations are more and more strict, the requirement of finished oil is continuously slowed down, the requirement of low-carbon olefin is still vigorous in a period of time in the future, and the acceleration oil refining is imperative to the chemical industry transformation development. Ethylene and propylene are two high-value basic organic chemical raw materials. Ethylene is an important basic material for organic chemical industry, and is mainly used for producing polyethylene, ethylene propylene rubber, polyvinyl chloride, ethanol, ethylene oxide, ethylene glycol, acetaldehyde, acetic acid, propionaldehyde, propionic acid, derivatives thereof and other basic organic synthetic materials, and is widely used in the pharmaceutical and chemical industries. Propylene is an important basic chemical raw material for producing propylene derivatives such as polypropylene, acrylonitrile and propylene oxide. Methyl tertiary butyl ether has higher octane number, is widely used as a gasoline octane number blending agent in the global scope, is unique, and is a clean gasoline production process with considerable economic benefit, wherein C5 and C6 olefins with reactivity in catalytic cracking light gasoline react with alcohols to generate alkyl tertiary alkyl ether in catalytic light gasoline ether chemical industry, so that the olefin content and vapor pressure of the catalytic gasoline are reduced, and simultaneously, low-value methanol is converted into a high-value gasoline product. CN102451674B discloses a catalyst for preparing isobutene by cracking methyl tert-butyl ether, a preparation method and application thereof, and aims to produce high-purity isobutene. The method adopts the preparation catalyst for preparing isobutene by methyl tertiary butyl ether pyrolysis, can complete the reaction under higher pressure, and has higher conversion rate and selectivity and long running period of the device. CN109225349a discloses a method for preparing isobutene catalyst by cracking methyl tert-butyl ether. The catalyst prepared by the method can reduce the temperature required by the cracking reaction of methyl tertiary butyl ether, has high selectivity of isobutene and methanol, high conversion rate, low energy consumption and high equipment utilization rate, and does not need to add inert substances such as water and the like into a reaction system. Most catalysts or processes for preparing olefins by ether cracking disclosed in the prior patent or literature are used for preparing high-purity olefins with four or more carbon numbers, for example, methyl tertiary butyl ether cracking is used for preparing high-purity isobutene, and few reports are made on preparing low-carbon olefins such as ethylene, propylene and the like by using ethers. Disclosure of Invention The application provides a method for preparing low-carbon olefin, which comprises the following steps: S1, enabling an ether raw material to be in contact with a catalytic conversion catalyst in a catalytic conversion reactor for catalytic conversion reaction to obtain a catalytic conversion reaction product, wherein the ether raw material has a structural formula of C nH2n+1-O-CmH2m+1, and m and n are each independently integers greater than or equal to 1, preferably 1-10, more preferably 1-6, and most preferably 1-4; S2, separating the catalytic conversion reaction product to obtain ethylene and propylene. In one embodiment, separating the catalytic conversion reaction product further results in a first recycle olefin stream comprising butenes and/or a second recycle olefin stream comprising C 5+ olefins; The method further comprises the steps of: S3, enabling at least one part of the first circulating olefin flow and/or at least one part of the second circulating olefin flow to enter an etherification unit together with optional external source olefin, and enabling the first circulating olefin flow and/or at least one part of the second circulating olefin flow to contact with an alcohol raw material under etherification conditions to obtain circulating ether materials and ether-post-olefin; s4, recycling the recycled ether material and the optional olefin after ether back to the catalytic conversion reactor for catalytic conversion reaction. In one embodiment, the ether feedstock is selected from one or more of methyl tertiary butyl ether, methyl tertiary amyl ether, methyl tertiary hexyl ether, methyl tertiary heptyl ether, methyl sec-butyl ether, methyl sec-amyl ether, methyl sec-hexyl ether, methyl sec-heptyl ether, ethyl tertiary but