CN106467449B - Method for preparing isobutene - Google Patents
Method for preparing isobutene Download PDFInfo
- Publication number
- CN106467449B CN106467449B CN201510511528.XA CN201510511528A CN106467449B CN 106467449 B CN106467449 B CN 106467449B CN 201510511528 A CN201510511528 A CN 201510511528A CN 106467449 B CN106467449 B CN 106467449B
- Authority
- CN
- China
- Prior art keywords
- butadiene
- catalyst
- butene
- isobutene
- sapo
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
The invention relates to a method for preparing isobutene, which takes tail gas of a butadiene extraction device as a raw material and comprises the following steps of firstly, selectively hydrogenating butadiene and alkyne in the tail gas of the butadiene extraction device by using a nickel catalyst to obtain a butene product; and step two, carrying out isomerization reaction on the butene product obtained in the step one by using an SAPO11 molecular sieve catalyst to obtain an isobutene product. The acetylene hydrocarbon and butadiene component content in the hydrogenation product obtained in the step one is less than 0.1 weight percent. The conversion rate of the butylene in the isomerization product reaches 33-38%, the isobutene selectivity reaches 85-91%, and the isobutene yield is 30-35%. The method provided by the invention can reasonably utilize the tail gas of the butadiene extraction device, and can also be used for other C4The stream produces isobutene.
Description
Technical Field
The invention relates to a method for preparing isobutene, in particular to a method for producing isobutene by selectively hydrogenating tail gas of a butadiene extraction device to remove alkyne, converting butadiene into butylene and further isomerizing the butylene, and belongs to the field of petrochemical industry.
Background
Isobutene is an important chemical raw material and is used for producing deep-processed products such as butyl rubber, polyisobutylene, diisobutylene, triisobutene, methacrylate, 2, 4-tert-butylcresol, tert-butylmercaptan, tert-butyl alcohol, tert-butylamine, methallyl chloride, methacrylic acid, methacrylonitrile, pivalaldehyde, isoprene and the like. However, the isobutene yield obtained by traditional petroleum catalytic cracking and thermal processing is far from meeting the market demand. In recent years, the price and demand for isobutene have increased rapidly.
Cracking carbon four is the main raw material for producing butadiene, and when butadiene is extracted, about 10% of tail gas of butadiene energy production, namely butadiene and carbon tetraalkyne, is usually discharged. Such as: the butadiene production capacity is 100 ten thousand tons per year, about 10 ten thousand tons of C-tetra acetylenes are discharged every year, and about 40-45 (Wt)% of butadiene is lost when C-tetra acetylenes are discharged. And the carbon tetra-alkyne is easy to cause fire explosion accidents, thereby bringing influence to the safety production of enterprises. Because of the problems of the utilization technology of the carbon tetraalkyne, many butadiene manufacturers can only dilute the carbon tetraalkyne with raffinate oil containing butane and butene and then discharge the carbon tetraalkyne into a torch system for combustion, so that the economic loss is huge and great environmental pollution is brought. With the increase of the production scale of butadiene, the amount of discharged carbon tetraalkynes is increased, and how to reasonably utilize the carbon tetraalkynes resource and change waste into valuable becomes a problem which needs to be solved urgently.
Patent CN101492334A discloses a method for improving the chemical utilization value of mixed carbon four, which adopts the byproduct mixed carbon four of a steam cracking device and the byproduct mixed carbon four of a Fluid Catalytic Cracking (FCC) device as raw materials, and realizes the technical proposal through the following steps: (1) adopting a selective hydrogenation technology to hydrogenate butadiene and alkyne in the mixed carbon four into mono-olefin; (2) isomerizing the n-butene in the first step product into 2-butene by adopting a hydroisomerization technology; (3) separating the second step product by a rectification technology to obtain a product isobutene; (4) disproportionating the 2-butene in the residual mixed carbon four in the third step and the ethylene to produce propylene by an olefin disproportionation technology; (5) and recycling the residual mixed carbon in the fourth step as cracking raw materials. The technical scheme defect that this patent described lies in: (1) the mixed C4 is subjected to selective hydrogenation and isomerization reaction to obtain a target product 2-butene, and then the 2-butene and ethylene are subjected to disproportionation reaction to obtain a final product propylene, wherein the technical scheme adopts two rectification processes and three reaction units, and has the advantages of long flow, complex process and large actual control difficulty; (2) the fifth step of recycling the remaining mixed C4 as the cracking raw material is based on the complete reaction of 2-butene and ethylene through disproportionation, and the remaining mixed C4 has almost no olefin and ethylene to meet the requirements of the cracking raw material, which is an ideal reaction and is difficult to realize in practical operation.
Patent CN102050695A discloses a method for utilizing butadiene extraction waste gas, which uses butadiene extraction device waste gas containing 0-5 (Wt)%, 30-70 (Wt)%, and 20-50 (Wt)% of vinyl acetylene as raw material, and uses nickel catalyst to hydrogenate alkyne, diolefin and mono-olefin in the waste gas to generate alkane through one-stage or multi-stage hydrogenation. The method has the following defects: (1) olefins in mixed C4 are not effectively utilized; (2) the hydrogen consumption is large and the energy consumption is high due to the complete hydrogenation of olefin and alkyne; (3) the economics of fully hydrogenating an olefin mixed with four carbons to an alkane is poor.
Disclosure of Invention
The invention provides a novel method for preparing isobutene, aiming at solving the problems of complex tail gas utilization process, high practical operation difficulty, high energy consumption and poor economical efficiency of a butadiene extraction device in the prior art.
The method for preparing isobutene provided by the invention takes tail gas of a butadiene extraction device as a raw material, and comprises two steps of selective hydrogenation and isomerization reaction, and specifically comprises the following steps:
the method comprises the following steps of firstly, using a nickel catalyst to selectively hydrogenate butadiene and alkyne in tail gas of a butadiene extraction device to obtain a butene product;
and step two, carrying out isomerization reaction on the butene product obtained in the step one by using an SAPO11 molecular sieve catalyst to obtain an isobutene product.
In the first step of the method, the composition of the tail gas of the butadiene extraction device is as follows: 0-40 wt% of butene, 20-65 wt% of butadiene and 10-30 wt% of butyne and vinyl acetylene. It should be noted that the raw material of the tail gas of the butadiene extraction unit is generally cracking C4Having a butadiene content30-40 wt%, and two-stage extraction to separate out 99.9 wt% polymer butadiene and the residual butadiene component of C rich in butyne and butadiene4Namely the tail gas of the butadiene extraction device. As described in the background section, this portion of the tail gas is typically flared and burned, thereby causing significant pollution and waste.
TiO is adopted as the nickel-based catalyst in the step one2-Al2O3The specific surface area of the composite carrier is 50-180 m2Per g, preferably 60 to 150m2(ii)/g; the pore volume is 0.2-1.0 ml/g, preferably 0.3-0.8 ml/g; the most probable pore diameter is 40 to 120 angstroms, preferably 60 to 100 angstroms. Preferably, the nickel-based catalyst contains metallic nickel in an amount of 5 to 35 wt%, preferably 10 to 25 wt%, based on the total weight of the catalyst. TiO 22Based on TiO2-Al2O3The total weight of the composite carrier is 5 to 40 wt%, preferably 10 to 30 wt%.
In the first step, the selected hydrogenation conditions are as follows: the inlet temperature of the reactor is 20-80 ℃, the reaction pressure is 1.0-3.0 MPa, the molar ratio of hydrogen to olefin is 0.7-4.0, and the liquid phase volume space velocity is 1-20 h-1. The preferable selective hydrogenation conditions are that the inlet temperature of the reactor is 30-70 ℃, the molar ratio of hydrogen to olefin is 0.8-3.0, and the liquid phase volume space velocity is 3-15 h-1。
In step two of the above method, the SAPO11 molecular sieve catalyst comprises SAPO-11 shaped bodies and silica supported on the SAPO-11 shaped bodies, wherein the SAPO-11 shaped bodies comprise the SAPO-11 molecular sieve. For related content, refer to chinese patent CN 102527429B. In the SAPO-11 molecular sieve catalyst, the content of silicon dioxide based on the weight of the SAPO-11 formed body is 0.1-1.5 wt%, and the content of the SAPO-11 molecular sieve based on the weight of the catalyst is 30-70 wt%.
And in the second step, the SAPO-11 molecular sieve catalyst is filled in a reactor in a fixed bed form, activated for 2 hours at 400-500 ℃, and then subjected to isomerization reaction at 300-400 ℃. Preferably, the SAPO-11 molecular sieve catalyst is activated for 2 hours at 320-380 ℃, and then isomerization reaction is carried out at the reaction temperature of 330-380 ℃ and under the conditions of the hydrogen-butene molar ratio of 1-4: 1 and normal pressure.
The reactor type that the invention can adopt is the fixed bed reactor, the reactor that step one and step two use can adopt the form of connecting in series, namely the hydrogenation product of step one is regarded as the raw materials of step two to carry on the isomerization reaction directly, produce isobutene.
In step one of the above process, the butadiene and acetylenic components of the butadiene extractor tail gas must be reduced to a sufficiently low level. The reason is that butadiene and alkyne have adverse effects on the catalytic isomerization reaction in the second step, which is mainly shown in that the highly unsaturated olefins are easy to polymerize into glue or carbon deposit at high temperature to block the pore channels of the SAPO-11 catalyst, so that the catalyst is inactivated. And (3) controlling the content of alkyne and butadiene components in the obtained hydrogenation product to be less than 0.1 weight percent through the selective hydrogenation process in the step one, and ensuring that the activity and the stability of the SAPO-11 catalyst in the step two meet the use requirements.
Through the isomerization reaction process in the second step of the method, the conversion rate of the butylene in the isomerization product reaches 33-38%, the selectivity of the isobutylene reaches 85-91%, and the yield of the isobutylene is 30-35%.
The method for preparing isobutene from the tail gas of the butadiene extraction device has the advantages of simple process, low energy consumption, strong operability, reasonable utilization of butene and high economic benefit. The method can reasonably utilize the tail gas of the butadiene extraction device, and can also be used for other C4The stream produces isobutene.
Detailed Description
The invention is further illustrated by the following examples. It is to be understood that the examples are for purposes of illustration and explanation only and are not intended to limit the present invention.
In examples 1 to 3, the general formula of each test result is as follows:
(1) the yield of n-butene, the yield of trans-2-butene and the yield of cis-2-butene in the first step of selective hydrogenation are calculated according to the following formulas:
the n-butene yield = (n-butene in the hydrogenation product — n-butene in the raw material) ÷ 1, 2-butadiene +1, 3-butadiene + vinylacetylene + 1-butyne) × 100% in the raw material. (since this formula mainly considers the conversion of acetylene and butadiene, the denominator contains only butadiene and acetylene, the same applies hereinafter.)
Yield of trans-2-butene ═ trans-2-butene in the hydrogenated product-trans-2-butene in the feed ÷ 1, 2-butadiene +1, 3-butadiene + vinylacetylene + 1-butyne in the feed × 100%.
The yield of cis-2-butene ═ cis-2-butene in the hydrogenated product-cis-2-butene in the feed ÷ 100% of (1, 2-butadiene +1, 3-butadiene + vinylacetylene + 1-butyne) in the feed.
(2) The conversion rate of butylene, isobutylene selectivity and isobutylene yield of the isomerization reaction in the second step are calculated according to the following formulas:
butene conversion% (% butene in hydrogenation product-butene in isomerization product) ÷ butene in hydrogenation product × 100%.
Isobutylene selectivity ═ isobutylene in the isomerized product-isobutylene in the hydrogenated product)/(butene in the hydrogenated product-butene in the isomerized product) × 100%.
The isobutylene yield% (% isobutylene in the isomerized product-isobutylene in the raw material) ÷ isobutylene in the raw material × 100%.
Wherein the 'butylene' is the sum of n-butylene, trans-2-butylene and cis-2-butylene, the 'butylene conversion rate' is the sum of the conversion rates of the n-butylene, the trans-2-butylene and the cis-2-butylene, and all the substances are counted by mole.
Example 1
This example illustrates an example of selective hydrogenation and isomerization of butadiene extraction unit tail gas feed 1.
The composition of the butadiene extractor tail gas feed 1 is shown in table 1.
The titanium oxide content was 16.2 wt%, the metallic nickel content was 17.5 wt%, and the specific surface area was 91m2Ni/TiO with pore volume of 0.48ml/g and most probable pore diameter of 110 angstrom2-Al2O350 ml of catalyst is filled in a reactor, and hydrogen flow is carried out at the reaction pressure of 1.5MPa and the temperature of 110 DEG CThe reaction solution was reduced for 8 hours in an amount of 40 ml/min.
The inlet temperature of the reactor is 30 ℃, the reaction pressure is 1.2MPa, the molar ratio of hydrogen to olefin is 1.0, and the liquid phase volume space velocity is 10h-1The feed 1 was fed at a recycle ratio of 9:1 (volume ratio of hydrogenation product to tail gas feed of 9:1) to give a hydrogenation product 1 having the composition shown in Table 2. The n-butene yield was 35.33%, the trans-2-butene yield was 36.57%, and the cis-2-butene yield was 24.52% by calculation.
100 ml of SAPO-11 molecular sieve catalyst (produced by Yanshan division of Beijing chemical institute of China) is filled in a reactor and activated for 2 hours at 370 ℃, the reaction temperature is 360 ℃, and the liquid phase volume space velocity is 0.8h-1Hydrogen to butene molar ratio 3: 1 and introducing the hydrogenation product 1 under the condition of normal pressure to carry out isomerization reaction. The product was analyzed by gas chromatography to give the isomerized product 1 with the composition shown in Table 3. The conversion of butene was calculated to be 33.88%, the selectivity of isobutene was calculated to be 91.12%, and the yield of isobutene was calculated to be 30.83%.
TABLE 1 composition of raw materials 1
TABLE 2 hydrogenation product 1 composition
TABLE 3 isomerization product 1 composition
Example 2
This example illustrates the results of selective hydrogenation of butadiene extracted tail gas using nickel-based catalysts of varying content.
Taking titanium oxide content of 17.3 wt%, metallic nickel content of 15.6 wt%, specific surface area of 88m2Ni/TiO with a pore volume of 0.47ml/g and a most probable pore diameter of 105 angstroms2-Al2O350 ml loading of catalystThe feed gas and reaction conditions in the reactor were the same as in example 1, and the results of selective hydrogenation are shown in Table 4. The n-butene yield was 34.8%, the trans-2-butene yield was 33.91%, and the cis-2-butene yield was 22.36% by calculation.
The results of the isomerization reaction are shown in Table 5. The conversion rate of the butylene is 37.93 percent, the selectivity of the isobutylene is 85.31 percent, and the yield of the isobutylene is 32.36 percent
TABLE 4 hydrogenation product 2 composition
TABLE 5 isomerization product 2 composition
Example 3
This example illustrates an example of selective hydrogenation and isomerization of butadiene extraction unit tail gas feed 2.
The two catalysts and the reaction conditions were the same as in example 1 except that the composition of the raw material of the butadiene extraction tail gas was changed as shown in Table 6.
The selective hydrogenation results are shown in Table 7, and the calculated yields of n-butene, trans-2-butene and cis-2-butene were 35.37%, 31.81% and 22.68%, respectively.
The results of the isomerization reaction are shown in Table 8, and the calculated results were 37.63% for butene conversion, 91.08% for isobutene selectivity, and 34.28% for isobutene yield.
TABLE 6 composition of feed 3
TABLE 7 hydrogenation product 3 composition
TABLE 8 isomerization product 3 composition
As can be seen from examples 1 and 3, under the same reaction conditions, Ni/TiO with 15-18 wt% of metallic nickel is selected2-Al2O3The catalyst is used for selectively hydrogenating the tail gas raw materials of the butadiene extraction device with different compositions, and the yield of n-butene in a hydrogenation product is 34-36%. In the embodiments 1 to 3, the obtained hydrogenation product is used as a raw material, and an SAPO-11 molecular sieve catalyst is used for carrying out an isomerization reaction under the same reaction conditions to obtain an isobutene product, wherein the selectivity of isobutene is 85 to 91%.
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.
Claims (7)
1. A method for preparing isobutene takes tail gas of a butadiene extraction device as a raw material, and comprises the following steps:
the method comprises the following steps of firstly, using a nickel catalyst to selectively hydrogenate butadiene and alkyne in tail gas of a butadiene extraction device to obtain a butene product;
secondly, carrying out isomerization reaction on the butene product obtained in the first step by using an SAPO-11 molecular sieve catalyst to obtain an isobutene product;
the composition of the tail gas of the butadiene extraction device is as follows: 0-40 wt% of butene, 20-65 wt% of butadiene, and 10-30 wt% of butyne and vinyl acetylene; and
the SAPO-11 molecular sieve catalyst is filled in a reactor in a fixed bed form, is activated for 2 hours at 400-500 ℃, and then is subjected to isomerization reaction at 300-400 ℃;
wherein the nickel-based catalyst adopts TiO2-Al2O3The specific surface area of the composite carrier is 50-180 m2The pore volume is 0.2-1.0 ml/g, and the most probable pore diameter is 40-120 angstroms;
in the first step, the selected hydrogenation conditions are as follows: the inlet temperature of the reactor is 20-80 ℃, the reaction pressure is 1.0-3.0 MPa, the molar ratio of hydrogen to olefin is 0.7-4.0, and the liquid phase volume space velocity is 1-20 h-1。
2. The method according to claim 1, wherein the specific surface area of the composite carrier is 60 to 150m2The pore volume is 0.3 to 0.8ml/g, and the most probable pore diameter is 60 to 100 angstroms.
3. The method according to claim 1 or 2, wherein the content of metallic nickel in the nickel-based catalyst is 5 to 35 wt% based on the total weight of the catalyst; TiO 22Based on TiO2-Al2O3The total weight of the composite carrier is 5-40 wt%.
4. The method according to claim 3, wherein the content of metallic nickel in the nickel-based catalyst is 10 to 25 wt% based on the total weight of the catalyst; TiO 22Based on TiO2-Al2O3The total weight of the composite carrier is 10-30 wt%.
5. The process of claim 1, wherein the hydrogenation conditions in step one are selected as follows: the inlet temperature of the reactor is 30-70 ℃, the molar ratio of hydrogen to olefin is 0.8-3.0, and the liquid phase volume space velocity is 3-15 h-1。
6. The method of claim 1, wherein the SAPO-11 molecular sieve catalyst has a silica content of 0.1 to 1.5 wt.% based on the weight of the SAPO-11 shaped bodies and a SAPO-11 molecular sieve content of 30 to 70 wt.% based on the weight of the catalyst.
7. The method of claim 1, wherein the SAPO-11 molecular sieve catalyst is activated at 320-380 ℃ for 2 hours, and then subjected to isomerization reaction at 330-380 ℃ and a hydrogen to butene molar ratio of 1-4: 1 under normal pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510511528.XA CN106467449B (en) | 2015-08-19 | 2015-08-19 | Method for preparing isobutene |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510511528.XA CN106467449B (en) | 2015-08-19 | 2015-08-19 | Method for preparing isobutene |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106467449A CN106467449A (en) | 2017-03-01 |
| CN106467449B true CN106467449B (en) | 2020-05-12 |
Family
ID=58214552
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510511528.XA Active CN106467449B (en) | 2015-08-19 | 2015-08-19 | Method for preparing isobutene |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106467449B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102070391A (en) * | 2011-01-12 | 2011-05-25 | 王伟跃 | Method for preparing isobutylene by comprehensively using mixed C4 |
| CN103787811A (en) * | 2012-10-30 | 2014-05-14 | 中国石油化工股份有限公司 | Method for hydrotreating butadiene tail gas |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2506297B1 (en) * | 1981-05-21 | 1986-05-02 | Inst Francais Du Petrole | PROCESS FOR ISOMERIZING OLEFINS |
| CA1319926C (en) * | 1988-06-17 | 1993-07-06 | Helmut X. Huber | Catalytic metal clusters and processes for their preparation |
-
2015
- 2015-08-19 CN CN201510511528.XA patent/CN106467449B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102070391A (en) * | 2011-01-12 | 2011-05-25 | 王伟跃 | Method for preparing isobutylene by comprehensively using mixed C4 |
| CN103787811A (en) * | 2012-10-30 | 2014-05-14 | 中国石油化工股份有限公司 | Method for hydrotreating butadiene tail gas |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106467449A (en) | 2017-03-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102070391B (en) | The method of comprehensive utilization mixed c 4 preparing isobutene | |
| CN106608791B (en) | Method for preparing propylene by comprehensively utilizing carbon tetrahydrocarbon | |
| CN100441554C (en) | Method of utilizing cracked, C5 fraction | |
| CN101475429B (en) | Method for comprehensive utilization of cracking C4 | |
| CN102886262B (en) | C4 selective acetylene hydrocarbon hydrogenation catalyst, preparation method and applications | |
| CN101914387B (en) | Catalysis upgrading method for cracking ethylene by-product carbon-9 | |
| CN104250194A (en) | Isobutene preparation method | |
| CN104945228A (en) | Method for preparing MTBE or isobutylene by adopting mixed butane | |
| CN109485535B (en) | Full hydrogenation method for unsaturated hydrocarbon in four-carbon fraction | |
| CN112007646A (en) | Carbon-tetrahydrocarbon full-hydrogenation catalyst, preparation method thereof and carbon-tetrahydrocarbon hydrogenation method | |
| CN103864564B (en) | Technique for processing methanol-to-propylene by-products | |
| CN105980340A (en) | Integration of MTO with on purpose butadiene | |
| CN106467449B (en) | Method for preparing isobutene | |
| CN102285851B (en) | Method for increasing yields of ethylene and propylene | |
| CN104487549A (en) | More energy efficient c5 hydrogenation process | |
| CN106467450B (en) | Method for preparing isobutene | |
| CN105295993B (en) | A kind of method of modified version liquefied gas through aromatization | |
| CN103864563A (en) | Method for preparing aromatic hydrocarbon from hydrocarbon tail oil byproducts produced in coal-based methanol to propylene process | |
| CN111943803B (en) | Method for synthesizing exo-tetrahydrodicyclopentadiene | |
| CN102285853A (en) | Method for increasing yield of propylene and ethylene by using cracked C4 as raw material | |
| CN106701182B (en) | The method of cracking carbon nine cut fraction hydrogenation | |
| CN106365942B (en) | Mixed C4 conversion method | |
| CN102285854B (en) | Method for increasing yields of propylene, ethylene and butadiene | |
| CN109485538B (en) | Selective hydrogenation method for alkyne in carbon four fraction | |
| CN112679300B (en) | Method for preparing propylene from carbon four raw material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |