CA1155463A - Hydrocarbon synthesis - Google Patents
Hydrocarbon synthesisInfo
- Publication number
- CA1155463A CA1155463A CA000375248A CA375248A CA1155463A CA 1155463 A CA1155463 A CA 1155463A CA 000375248 A CA000375248 A CA 000375248A CA 375248 A CA375248 A CA 375248A CA 1155463 A CA1155463 A CA 1155463A
- Authority
- CA
- Canada
- Prior art keywords
- process according
- synthesis
- alcohol
- catalyst
- range
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
- C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
- C07C29/153—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the catalyst used
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
- C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
- C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
- C07C29/1512—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by reaction conditions
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
- C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
- C07C29/1516—Multisteps
- C07C29/1518—Multisteps one step being the formation of initial mixture of carbon oxides and hydrogen for synthesis
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2529/00—Catalysts comprising molecular sieves
- C07C2529/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites, pillared clays
- C07C2529/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
- C07C2529/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Abstract
Abstract Aromatic and/or unsaturated hydrocarbons are produced by generating synthesis gas, synthesising an alcohol mature and subjecting at least one synthesis product to an alcohol conver-sion catalyst such as a zeolite of the Z5M-5 family. The syn-thesis catalyst contains the oxides of chromium, zinc and of at least one other metal having a divalent oxide more strongly basic than zinc oxide, for example of manganese.
Description
drocarbon synthesis ~h;s invention relates to hydrocarbon synthesis and in particular to a process for producing aromatic and/or unsaturated hydrocarbons for synthesis gas.
~he reaction of aliphatic compounds of low molecular weight to give such hydrocarbons suitable as gasoline constituents or as chemical intermediates has received much study since the early 1970s. As examples of patent specifications describing this process there may be mentioned ~E patents 1446522 and 1563345.
~sually the catalyst for this reaction has been a crystalline aluminosilicate zeolite having pores about 6 ~n~strom units in diameter, but recently the use of otherwise similar zeolites con-t~;ning other oxides, for example iron oxide, has been described.
According to the invention a process for producing aromatic and/or unsaturated hydrocarbons comprises the steps of (a) generating a synthesis gas cont ;n;ng carbon ~onoxide and hydrogen by reacting a carbonaceous feedstock with oxygen and/or steam and, to the extent neces-sa~y, purifying the gas and subjecting it to the shift reaction and carbon dioxide removal;
(b) synthesising one or more aliphatic alcohols containing more than one carbon atom;
(c) subjecting at least one synthesis product to an alcohol conversion catalyst whereby to produce aromatic and/
or unsaturated hydrocarbons;
and is characterised by using in step (b) a catalyst comprising ~:
.: , .. .
. ~
.
~ .
~L ~S54~3
~he reaction of aliphatic compounds of low molecular weight to give such hydrocarbons suitable as gasoline constituents or as chemical intermediates has received much study since the early 1970s. As examples of patent specifications describing this process there may be mentioned ~E patents 1446522 and 1563345.
~sually the catalyst for this reaction has been a crystalline aluminosilicate zeolite having pores about 6 ~n~strom units in diameter, but recently the use of otherwise similar zeolites con-t~;ning other oxides, for example iron oxide, has been described.
According to the invention a process for producing aromatic and/or unsaturated hydrocarbons comprises the steps of (a) generating a synthesis gas cont ;n;ng carbon ~onoxide and hydrogen by reacting a carbonaceous feedstock with oxygen and/or steam and, to the extent neces-sa~y, purifying the gas and subjecting it to the shift reaction and carbon dioxide removal;
(b) synthesising one or more aliphatic alcohols containing more than one carbon atom;
(c) subjecting at least one synthesis product to an alcohol conversion catalyst whereby to produce aromatic and/
or unsaturated hydrocarbons;
and is characterised by using in step (b) a catalyst comprising ~:
.: , .. .
. ~
.
~ .
~L ~S54~3
2 3 31254 the oxides of chromium, zinc and at least one other metal having a divalent oxide difficultlyreducible to the metal and more strongly basic t~an zinc oxide.
Generation of synthesis gas is ve~y suitably by partial oxidation, preferably using high-concentration oxygen (over 95% V/v) to avoid intriducing non-reactive gases such as nitrogen and noble gases. ~he gases produced by partial oxidation of coal or heavy oil typically contain (% V/v) 25 to 65 of hydrogen, 20 to 60 of carbon monoxide, l to lO of carbon dioxide and 0.1 to lO of non-reacting gases. Consequently they may require only minor adjust-ment to produce the synthesis gas feed. If the hydrogen content would be too high in such a partial oxidation process as designed for ammonia or methanol production, a variant of the process using carbon dioxide as part of its feed is preferably used. Since methane is a non-reactive gas in synthesis and aromatisation, the partial oxidation process used is preferably one having a high flame-zone temperature (over 1700C), such as the ~oppers-~otzek or Shell-Koppers process. ~he methane content of the partial oxidation gas is preferably under 5% V/v on a dry basis.
After partial oxidation the raw gas is subjected to coarse purification to remove dust and carbon, then to sulphur compounds removal and fine purification stages to remove minor components such as o.Yygen, nitrogen 02ides and hydrogen cyanide.
~sually carbon dioxide removal is required. Processes for such stages are well known. If synthesis gas generation is by catalytic steam reforming or partial oxidation of a gaseous hydrocarbon, carbon dioxide is preferably used as a re~tant, otherwnse a sub-sequent reverse-shift reaction is necessary. ~sn~lly the corres-ponding process starting from a normally liquid hydrocarbon is of little interest, since such hydrocarbons can be converted directly to aromatic hydrocarbons by processes established in the petroleum industry.
Whichever synthesis gas generation,purification and com-position adjustment steps are used, the aggregate of carbon dioxide and water vapour content of the gas fed to the synthesis is
Generation of synthesis gas is ve~y suitably by partial oxidation, preferably using high-concentration oxygen (over 95% V/v) to avoid intriducing non-reactive gases such as nitrogen and noble gases. ~he gases produced by partial oxidation of coal or heavy oil typically contain (% V/v) 25 to 65 of hydrogen, 20 to 60 of carbon monoxide, l to lO of carbon dioxide and 0.1 to lO of non-reacting gases. Consequently they may require only minor adjust-ment to produce the synthesis gas feed. If the hydrogen content would be too high in such a partial oxidation process as designed for ammonia or methanol production, a variant of the process using carbon dioxide as part of its feed is preferably used. Since methane is a non-reactive gas in synthesis and aromatisation, the partial oxidation process used is preferably one having a high flame-zone temperature (over 1700C), such as the ~oppers-~otzek or Shell-Koppers process. ~he methane content of the partial oxidation gas is preferably under 5% V/v on a dry basis.
After partial oxidation the raw gas is subjected to coarse purification to remove dust and carbon, then to sulphur compounds removal and fine purification stages to remove minor components such as o.Yygen, nitrogen 02ides and hydrogen cyanide.
~sually carbon dioxide removal is required. Processes for such stages are well known. If synthesis gas generation is by catalytic steam reforming or partial oxidation of a gaseous hydrocarbon, carbon dioxide is preferably used as a re~tant, otherwnse a sub-sequent reverse-shift reaction is necessary. ~sn~lly the corres-ponding process starting from a normally liquid hydrocarbon is of little interest, since such hydrocarbons can be converted directly to aromatic hydrocarbons by processes established in the petroleum industry.
Whichever synthesis gas generation,purification and com-position adjustment steps are used, the aggregate of carbon dioxide and water vapour content of the gas fed to the synthesis is
3 ~ 31254 preferably less than 10, more preferably in the range up to 5% /v.
If desired, the gas fed to the synthesis can contain methanol, pos-sibly recycled from downstream step or possibly from a separate synthesis or an external source. Similarly ethers such as dimethyl ether and other alcohols can be included in the feed. ~he ratio of hydrogen to carbon monoxide is suitably in the range 0.5 to 5.0, more preferably 0.8 to 105 in order to provide for removal of water ` by reaction with carbon monoxide and thus to favour fo~mation of alcohols other than methanol.
The synthesis is carried out at an outlet temperature in the range 350 - 500C and a pressure in the range 150 - 400 bar abs.
~ he synthesis step is preferably operated in a reaction system in which the reacting gas is sub~ected to cooling. If des-ired a fluidised catalyst can be used, suspended in a reactorequipped with coolant-contP;n;ng tubes. When using a fixed bed of catalyst, for continuous cooling the catalyst can be disposed in tubes surrounded by cooling medium, such as is described by ~otowski in Chemische Technik 1963, 15, 204 - 205 or as described in ~K 1205156. Alternatively the catalyst can be in a vessel traversed by tubes contP;n~ng a cooling medium or otherwise pro-vided with indirect heat exchange surfaces. As described by Kotowski, a plurality of such reactors (for example 3 to 6), pos-sibly with intervening indirect cooling or cool synthesis gas in-jection, can be operated in series, in order to increase conver-sion of synthesis gas to the maximum practicable. Preferably a liquid product is removed between beds and the unreacted gas pas-sed to a further bed. Alternatively such gas can be recycled. In another ~ystem with cooling the catalyst is disposed in adiabatic beds alternating with cooling means, ~hich can be indirect heat exchanger~ or can be cool gas in~ection chambers. Several such beds and cooling means can be disposed in the same reactor shell or in different reactor shells.
The ratio of higher alcohols (mainly C2 to C5) to methanol in the reacted synthesis gas is typically in the range 1 ~55~63
If desired, the gas fed to the synthesis can contain methanol, pos-sibly recycled from downstream step or possibly from a separate synthesis or an external source. Similarly ethers such as dimethyl ether and other alcohols can be included in the feed. ~he ratio of hydrogen to carbon monoxide is suitably in the range 0.5 to 5.0, more preferably 0.8 to 105 in order to provide for removal of water ` by reaction with carbon monoxide and thus to favour fo~mation of alcohols other than methanol.
The synthesis is carried out at an outlet temperature in the range 350 - 500C and a pressure in the range 150 - 400 bar abs.
~ he synthesis step is preferably operated in a reaction system in which the reacting gas is sub~ected to cooling. If des-ired a fluidised catalyst can be used, suspended in a reactorequipped with coolant-contP;n;ng tubes. When using a fixed bed of catalyst, for continuous cooling the catalyst can be disposed in tubes surrounded by cooling medium, such as is described by ~otowski in Chemische Technik 1963, 15, 204 - 205 or as described in ~K 1205156. Alternatively the catalyst can be in a vessel traversed by tubes contP;n~ng a cooling medium or otherwise pro-vided with indirect heat exchange surfaces. As described by Kotowski, a plurality of such reactors (for example 3 to 6), pos-sibly with intervening indirect cooling or cool synthesis gas in-jection, can be operated in series, in order to increase conver-sion of synthesis gas to the maximum practicable. Preferably a liquid product is removed between beds and the unreacted gas pas-sed to a further bed. Alternatively such gas can be recycled. In another ~ystem with cooling the catalyst is disposed in adiabatic beds alternating with cooling means, ~hich can be indirect heat exchanger~ or can be cool gas in~ection chambers. Several such beds and cooling means can be disposed in the same reactor shell or in different reactor shells.
The ratio of higher alcohols (mainly C2 to C5) to methanol in the reacted synthesis gas is typically in the range 1 ~55~63
4 ~ 31254 0.1 to 2Ø ~fter cooling and separation of liquid products, that product can be distilled to produce a higher alcohol fraction, to be sent forward to aromatisation, and a methanol fraction, to be recycled at least partly to the synthesis.
~he synthesis catalyst contains the three oxides prefer-ably in the molar ranges bounded on a triangular diagram by the following combinations, in which M represents the divalent metal having an oxide difficultly reduced to metal and more basic than æinc oxide:
lO Cr M Zn ~hus the following proportions are especially suitable:
Cr M Zn 28.5 43 28.5 ~he cat~lyst preferably contains an alkali metal compound, espec-ially of potassium, rubidium or cesium. ~ suitable content of such compound is in the range 0.1 to 2.0~ W/w calculated as equiv-alent ~ 0. Metal ~ is preferably manganese but can be, for example, magnesium. In addition the catalyst can contain a promoting quan-tity of cobalt suitably up to 6% by metal atoms. m e effect of cobalt is to increase the proportion of ethanol and propanol at the expense of butanol and higher alcohols. Since cobalt also increases the fraction of carbon monoxide converted to methane, it is prefer-red not to have more than ~/0 of cobalt in the catalyst, unless there is provision for recycling it to synthesis gas generation or for otherwise using it.
If desired, the synthesis product can be subjected to an alcohol dehydrati~n catalyst. This is very suitably alumina, pre-ferably in a form having a surface area when anhydrous of at least 50 m2/g. ~hose gamma alumina and activated aluminas having surface areas in the range lO0 - 500 m2/g can be used. Other dehydrating agents include amorphous aluminosilicates, c~ystalline l 155~B3 aluminosilicates such as zeolites of large (over 7 Angstrom units), medium (5-7) or small (under 5) pore diameter and solid or solid-supported acids such as isopolyacid, heterpolyacids and phosphoric acids on silica. If a crystalline zeolite of medium or large pore diameter is used it should preferably not be in an acidic form such as the hydrogen or rare earth form, since this would result in deposition of higher hydrocarbon derivatives including possibly solid polymers and carbon at the surface of the dehydration catalyst and snythesis catalyst, which would not withstand the treatments necessary to remove such deposits.
The alcohol conversion catalyst can be an oxidic solid having ion-exchange properties and capable of an acid function when carrying hydrogen, oniums or polyvalent cations. An import-ant class of such solids have a crystalline structure affordingentry-ports uniform in diameter and capable of admitting molecules of diameter in the range 5-7 Angstrom units. In an alternative or additional characterisation such solids have been identified by the relative rates at which n-hexane and 3-methylpentane under-go catalytic cracking in their presence, expressed by a parameterreferred to by Mobil Oil Corporation technologists as the "con-straint index". (This is defined in, for example, UK 1446522 cited above).
For aromatisation the catalyst is typically a zeolite ~5 of the ZSM-5 family, which includes the following particular members:
ZSM 5 (US 3702886) ZSM 11 (US 3709979) ZSM 12 (US 3832449) ZSM 21 (UK 1444481) ZSM 35 (US 4016245) ZSM 38 (US 4105541) Zeta - 1 (Netherlands application 7512644 published May 4, 1976) Zeta - 3 (Netherlands application 7512645 published May 4, 1976) UCC unnamed (German application 2704039 published August 18, 1977) `: :
1 ~55~63 Ferrosilicate (Belgian application 861830 published June 14,1978) sorosilicate (German application 2746790 published April 20, 1978) If desired, the alcohol may be subjected to a pre-liminary conversion to olefins, using a selective zeolite such as FU-l or Mn-Y or one of the above zeolites treated to induce selectivity or used in non-aromatising conditions. After such preliminary conversions the reaction may be cooled to separate water and the relatively dry gas phase sub~ected to aromatisation.
If unsaturated hydrocarbons are required, such a pre-liminary conversion is followed by product recovery.
The process conditions for the alcohol conversion re-action are typically as follows:
Temperature C 260 - ~50, especially 350 to 400.
Pressure, bar abs over 1, and preferably 150 to 400 bar abs.
Space velocity sufficient to provide 70 to 10%
conversion It can be performed in a fixed or fluidised bed, and preferably in the presence of gaseous hydrocarbons and/or carbon dioxide recycled from product recovery.
The product of the aromatisation step includes water, carbon dioxide (mainly unchanged feed), gaseous hydrocarbons (usually 30 - 60% of total hydrocarbon product), aromatic hydro-carbons (20 - 50~) and non-aromatic liquid hydrocarbons (up to 30~). On cooling the reacted aromatisation gas water separates as the bottom layer, with liquid hydrocarbons floating on it. The water is run off but can be used in a humidifier in the synthesis gas generation section in order to avoid wasting organic materials dissolved in it. The liquid hydrocarbon layer can be used directly as a gasoline constituent or can be subjected to fractionation.
The gaseous hydrocarbon fraction is resolved by known means into unreactive gases methane and ethane (which are recycled to synthesis gas generation) and reactive gases ethylene, propylene, propane, butane and butenes (which are thereafter reacted together to form B
1 155~63 7 ~ 31254 iso paraffin constituents of gasoline). It is withi~ the inven-~tion to include part of the alcohol product of the synthesis step in such gasoline.
One preferred form of the process is shown as a flow diagram in the accompanying drawing.
~ atural gas 10, steam 12 and recycled carbon dioxide are mixed and fed to-catalys-t-filled steam reformer tubes 16 heated externally by furnace 18. Reaction takes place to prod~ce-a primary reformer gas containing carbon monoxide and hydrogen, as well as a little unreacted methane and excess steam and carbon dioxide. ~he gas is cooled at 20, which represents useful heat recoveries as high pressure steam-, hot water and preheated natural gas and carbon dioxide, followed by cooling to below the dewpoint of water. Water is separated in catchpot 22 and flows out at 24 for re-use or to waste. The gas passes out overhead to packed carbon dioxide absorber 26 in which it flows counter-current to a descending stream of a solution such as aqueous potassium car-bonate fed in at 28. ~he resulting carbonated solution leaves the bottom of absorber 26 and is pumped to the top of regenerator 30 which it enters at 32. Carbon dioæide stripped from the solu-tion is passed overhead and joins at 36 the recycle line as part of the supply of carbon dioxide 14. (If the reaction in tube 16 i9 conducted at a sufficiently high temperature, low pressure and low steam-to-carbon ratio, items 26 - 36 need not be used. If desired, items 26 - 38 can be disposed between items 40 and 42 des-cribed below). ~he gas passes via drier 38 and compressor 40 to synthesis reactor 42, which is of the externally-cooled tubular type as used for the Fischer-~ropsch reaction and contains in its tubes a 1:3:2 (by metal atoms) mLxture of oxides of chromium, man-ganese and zinc as synthesis catalyst. Substantial conversion tomethanol and higher alcohols takes place. ~he re~ulting gas is adjusted if necessa~y to aromatisation temperature in heat exohanger 44, partly reacted in first reactor 46 and m;Yed with cold recycle gas at 48. (If desired, a part stream of the gas recycled at 48 can be fed to the inlet of synthesis reactor 42). Aromatisation takes
~he synthesis catalyst contains the three oxides prefer-ably in the molar ranges bounded on a triangular diagram by the following combinations, in which M represents the divalent metal having an oxide difficultly reduced to metal and more basic than æinc oxide:
lO Cr M Zn ~hus the following proportions are especially suitable:
Cr M Zn 28.5 43 28.5 ~he cat~lyst preferably contains an alkali metal compound, espec-ially of potassium, rubidium or cesium. ~ suitable content of such compound is in the range 0.1 to 2.0~ W/w calculated as equiv-alent ~ 0. Metal ~ is preferably manganese but can be, for example, magnesium. In addition the catalyst can contain a promoting quan-tity of cobalt suitably up to 6% by metal atoms. m e effect of cobalt is to increase the proportion of ethanol and propanol at the expense of butanol and higher alcohols. Since cobalt also increases the fraction of carbon monoxide converted to methane, it is prefer-red not to have more than ~/0 of cobalt in the catalyst, unless there is provision for recycling it to synthesis gas generation or for otherwise using it.
If desired, the synthesis product can be subjected to an alcohol dehydrati~n catalyst. This is very suitably alumina, pre-ferably in a form having a surface area when anhydrous of at least 50 m2/g. ~hose gamma alumina and activated aluminas having surface areas in the range lO0 - 500 m2/g can be used. Other dehydrating agents include amorphous aluminosilicates, c~ystalline l 155~B3 aluminosilicates such as zeolites of large (over 7 Angstrom units), medium (5-7) or small (under 5) pore diameter and solid or solid-supported acids such as isopolyacid, heterpolyacids and phosphoric acids on silica. If a crystalline zeolite of medium or large pore diameter is used it should preferably not be in an acidic form such as the hydrogen or rare earth form, since this would result in deposition of higher hydrocarbon derivatives including possibly solid polymers and carbon at the surface of the dehydration catalyst and snythesis catalyst, which would not withstand the treatments necessary to remove such deposits.
The alcohol conversion catalyst can be an oxidic solid having ion-exchange properties and capable of an acid function when carrying hydrogen, oniums or polyvalent cations. An import-ant class of such solids have a crystalline structure affordingentry-ports uniform in diameter and capable of admitting molecules of diameter in the range 5-7 Angstrom units. In an alternative or additional characterisation such solids have been identified by the relative rates at which n-hexane and 3-methylpentane under-go catalytic cracking in their presence, expressed by a parameterreferred to by Mobil Oil Corporation technologists as the "con-straint index". (This is defined in, for example, UK 1446522 cited above).
For aromatisation the catalyst is typically a zeolite ~5 of the ZSM-5 family, which includes the following particular members:
ZSM 5 (US 3702886) ZSM 11 (US 3709979) ZSM 12 (US 3832449) ZSM 21 (UK 1444481) ZSM 35 (US 4016245) ZSM 38 (US 4105541) Zeta - 1 (Netherlands application 7512644 published May 4, 1976) Zeta - 3 (Netherlands application 7512645 published May 4, 1976) UCC unnamed (German application 2704039 published August 18, 1977) `: :
1 ~55~63 Ferrosilicate (Belgian application 861830 published June 14,1978) sorosilicate (German application 2746790 published April 20, 1978) If desired, the alcohol may be subjected to a pre-liminary conversion to olefins, using a selective zeolite such as FU-l or Mn-Y or one of the above zeolites treated to induce selectivity or used in non-aromatising conditions. After such preliminary conversions the reaction may be cooled to separate water and the relatively dry gas phase sub~ected to aromatisation.
If unsaturated hydrocarbons are required, such a pre-liminary conversion is followed by product recovery.
The process conditions for the alcohol conversion re-action are typically as follows:
Temperature C 260 - ~50, especially 350 to 400.
Pressure, bar abs over 1, and preferably 150 to 400 bar abs.
Space velocity sufficient to provide 70 to 10%
conversion It can be performed in a fixed or fluidised bed, and preferably in the presence of gaseous hydrocarbons and/or carbon dioxide recycled from product recovery.
The product of the aromatisation step includes water, carbon dioxide (mainly unchanged feed), gaseous hydrocarbons (usually 30 - 60% of total hydrocarbon product), aromatic hydro-carbons (20 - 50~) and non-aromatic liquid hydrocarbons (up to 30~). On cooling the reacted aromatisation gas water separates as the bottom layer, with liquid hydrocarbons floating on it. The water is run off but can be used in a humidifier in the synthesis gas generation section in order to avoid wasting organic materials dissolved in it. The liquid hydrocarbon layer can be used directly as a gasoline constituent or can be subjected to fractionation.
The gaseous hydrocarbon fraction is resolved by known means into unreactive gases methane and ethane (which are recycled to synthesis gas generation) and reactive gases ethylene, propylene, propane, butane and butenes (which are thereafter reacted together to form B
1 155~63 7 ~ 31254 iso paraffin constituents of gasoline). It is withi~ the inven-~tion to include part of the alcohol product of the synthesis step in such gasoline.
One preferred form of the process is shown as a flow diagram in the accompanying drawing.
~ atural gas 10, steam 12 and recycled carbon dioxide are mixed and fed to-catalys-t-filled steam reformer tubes 16 heated externally by furnace 18. Reaction takes place to prod~ce-a primary reformer gas containing carbon monoxide and hydrogen, as well as a little unreacted methane and excess steam and carbon dioxide. ~he gas is cooled at 20, which represents useful heat recoveries as high pressure steam-, hot water and preheated natural gas and carbon dioxide, followed by cooling to below the dewpoint of water. Water is separated in catchpot 22 and flows out at 24 for re-use or to waste. The gas passes out overhead to packed carbon dioxide absorber 26 in which it flows counter-current to a descending stream of a solution such as aqueous potassium car-bonate fed in at 28. ~he resulting carbonated solution leaves the bottom of absorber 26 and is pumped to the top of regenerator 30 which it enters at 32. Carbon dioæide stripped from the solu-tion is passed overhead and joins at 36 the recycle line as part of the supply of carbon dioxide 14. (If the reaction in tube 16 i9 conducted at a sufficiently high temperature, low pressure and low steam-to-carbon ratio, items 26 - 36 need not be used. If desired, items 26 - 38 can be disposed between items 40 and 42 des-cribed below). ~he gas passes via drier 38 and compressor 40 to synthesis reactor 42, which is of the externally-cooled tubular type as used for the Fischer-~ropsch reaction and contains in its tubes a 1:3:2 (by metal atoms) mLxture of oxides of chromium, man-ganese and zinc as synthesis catalyst. Substantial conversion tomethanol and higher alcohols takes place. ~he re~ulting gas is adjusted if necessa~y to aromatisation temperature in heat exohanger 44, partly reacted in first reactor 46 and m;Yed with cold recycle gas at 48. (If desired, a part stream of the gas recycled at 48 can be fed to the inlet of synthesis reactor 42). Aromatisation takes
5 ~ 6 ~
8 ~ ~1254 place in second reactor 50. ~he resulting hot gas is cooled in heat exchanger 52, initially with heat recovery and then to be- -low its dewpoint. A liquid phase is separated in catchpot 54 and run out to separator 56, from which a lower, aqueous~ layer is run off to waste or recove~y and an aromatics-rich hydrocar-bon layer is taken at 60. Gas passing overhead from catchpot 54 is divided at 62 into an aromatisation recycle stream fed to point 48 as mentioned above and a selective recycle stream, ~hich is fed to fractionating column 64. The bottoms 66 from column 64, rich in C3 to C5 paraffins and olefins, are passed to an alkyl-ation unit (not shown). The overhead 68~ consisting mainly of carbon dioxide, methane, ethane and ethylene, is fed to point 36 as part of the feed to primary reformer tube 16.
It will be appreciated that for the sake of brevity ~inor plant items such as absorbent liquor pumps between items 26 and 30, gas recycle pu~ps and possible gas pressure let down tur-bines, have been omitted.
In experimental runs using zeolite H-ZSM 5 for the aro-matisation steps in items 50 - 54, good yields of a product of high octane member were obtained using the product of synthesis over catalysts containing the oxides of chromium, magnesium and zinc in the mol æ ratios 17:50:33 a~d 28,5:43:28.5. The octane numbers appeared to be significantly higher than when using methanol as the sole feed to aromatisation.
In a typical run the following alcohol mixture (% W/w) was fed to the conversion catalyst: ethanol 4, l-propanol 8~
isobutanol 60~ l-pentanol 8~ 2-octanol 10, 4 octanol 10. The catalyst E-ZSM 5 was maintained at 450C, the pressure was atmos-pheric and the liquid hourly space velocity 10 by volume. ~rom 30 1005 ml of feed there were obtained 205 ml of liquid hYdrocarbon product with a Research Octane number of 97.9 and 110 1 of C1 - C4 hydroc æbons, of which 96% V/v were reactive.
PA ~ C ~
35 17 March 1981
8 ~ ~1254 place in second reactor 50. ~he resulting hot gas is cooled in heat exchanger 52, initially with heat recovery and then to be- -low its dewpoint. A liquid phase is separated in catchpot 54 and run out to separator 56, from which a lower, aqueous~ layer is run off to waste or recove~y and an aromatics-rich hydrocar-bon layer is taken at 60. Gas passing overhead from catchpot 54 is divided at 62 into an aromatisation recycle stream fed to point 48 as mentioned above and a selective recycle stream, ~hich is fed to fractionating column 64. The bottoms 66 from column 64, rich in C3 to C5 paraffins and olefins, are passed to an alkyl-ation unit (not shown). The overhead 68~ consisting mainly of carbon dioxide, methane, ethane and ethylene, is fed to point 36 as part of the feed to primary reformer tube 16.
It will be appreciated that for the sake of brevity ~inor plant items such as absorbent liquor pumps between items 26 and 30, gas recycle pu~ps and possible gas pressure let down tur-bines, have been omitted.
In experimental runs using zeolite H-ZSM 5 for the aro-matisation steps in items 50 - 54, good yields of a product of high octane member were obtained using the product of synthesis over catalysts containing the oxides of chromium, magnesium and zinc in the mol æ ratios 17:50:33 a~d 28,5:43:28.5. The octane numbers appeared to be significantly higher than when using methanol as the sole feed to aromatisation.
In a typical run the following alcohol mixture (% W/w) was fed to the conversion catalyst: ethanol 4, l-propanol 8~
isobutanol 60~ l-pentanol 8~ 2-octanol 10, 4 octanol 10. The catalyst E-ZSM 5 was maintained at 450C, the pressure was atmos-pheric and the liquid hourly space velocity 10 by volume. ~rom 30 1005 ml of feed there were obtained 205 ml of liquid hYdrocarbon product with a Research Octane number of 97.9 and 110 1 of C1 - C4 hydroc æbons, of which 96% V/v were reactive.
PA ~ C ~
35 17 March 1981
Claims (9)
1. A process for producing aromatic hydrocarbons which comprises the steps of (a) generating a synthesis gas containing carbon monoxide and hydrogen by reacting a carbonaceous feedstock with oxygen and/or steam and, to the extent necessary, purifying the gas and subjecting it to the shift reaction and carbon dioxide removal;
(b) synthesising one or more aliphatic alcohols containing more than one carbon atom;
(c) subjecting at least one synthesis product in the gaseous phase to an alcohol conversion catalyst whereby to produce aromatic hydrocarbons;
in which in step (b) there is used a catalyst consisting essentially of the oxides of chromium, zinc and at least one other metal M having a divalent oxide difficultly reducible to the metal and more strongly basic than zinc oxide, said oxides being present in the molar ranges bounded on a triangular diagram by the following combinations:
Cr M Zn
(b) synthesising one or more aliphatic alcohols containing more than one carbon atom;
(c) subjecting at least one synthesis product in the gaseous phase to an alcohol conversion catalyst whereby to produce aromatic hydrocarbons;
in which in step (b) there is used a catalyst consisting essentially of the oxides of chromium, zinc and at least one other metal M having a divalent oxide difficultly reducible to the metal and more strongly basic than zinc oxide, said oxides being present in the molar ranges bounded on a triangular diagram by the following combinations:
Cr M Zn
2. A process according to Claim 1 in which the catalyst contains an alkali metal compound to the extent of 0.1 to 2.0% W/w calculated as equivalent K2O.
3. A process according to Claim 1 in which the said other metal is manganese.
4. A process according to Claim 1 in which the alcohol conversion catalyst is an oxidic solid having ion exchange properties, capable of an acid function and having a crystalline structure affording entry-ports uniform in diameter and capable of admitting molecules of diameter in the range 5 - 7 Angstrom units.
5. A process according to Claim 4 in which the alcohol conversion is aromatisation over a zeolite of the ZSM-5 family.
6. A process according to Claim 1 in which the alcohol synthesis is carried out at a temperature in the range 350 - 500°C and a pressure in the range 150 - 400 bar abs.
7. A process according to Claim 1 in which the alcohol conversion is carried out at a temperature in the range 260 - 450°C, a pressure in the range 150 - 400 bar abs. and a space velocity sufficient to provide 70 - 10%
conversion.
conversion.
8. A process according to Claim 1 in which the whole product of the alcohol synthesis is fed to the alcohol conversion step.
9. A process according to Claim 1 which includes the steps of cooling the gaseous product of the alcohol conversion, separating water and aromatic hydrocarbons as liquid phases, separating a gaseous hydrocarbon fraction, resolving that fraction into unreactive methane and ethane gases and reactive ethylene, propylene, propane, butane and butenes gases, recycling the unreactive gases to synthesis gas generation and reacting the reactive gases together to produce isoparaffins.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8012103 | 1980-04-11 | ||
| GB8012103 | 1980-04-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1155463A true CA1155463A (en) | 1983-10-18 |
Family
ID=10512753
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000375248A Expired CA1155463A (en) | 1980-04-11 | 1981-04-10 | Hydrocarbon synthesis |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS56159286A (en) |
| AU (1) | AU6879381A (en) |
| CA (1) | CA1155463A (en) |
| DE (1) | DE3113838A1 (en) |
| IN (1) | IN155637B (en) |
| NZ (1) | NZ196644A (en) |
| ZA (1) | ZA812157B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4607055A (en) * | 1985-07-03 | 1986-08-19 | Texaco Inc. | Aliphatic alcohol production |
| US4607056A (en) * | 1985-07-03 | 1986-08-19 | Texaco Inc. | Mixed aliphatic alcohol production |
| US4616040A (en) * | 1985-07-22 | 1986-10-07 | Texaco Inc. | Production of C2 -C6 aliphatic alcohols |
| US4661525A (en) * | 1984-03-28 | 1987-04-28 | Texaco Inc. | Process for producing lower aliphatic alcohols |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NZ202810A (en) * | 1981-12-23 | 1985-02-28 | Mobil Oil Corp | Converting fossil fuel successively to synthesis gas,oxygenates and hydrocarbons,then upgrading |
| NZ202811A (en) * | 1981-12-23 | 1984-12-14 | Mobil Oil Corp | Converting fossil fuel to hydrocarbon mixture rich in benzene,toluene and xylene |
| FR2545080B1 (en) * | 1983-04-29 | 1987-11-13 | Inst Francais Du Petrole | PROCESS FOR THE PRODUCTION OF ALCOHOLS FROM LIGHT HYDROCARBONS |
| CA1240708A (en) * | 1983-11-15 | 1988-08-16 | Johannes K. Minderhoud | Process for the preparation of hydrocarbons |
| US5004862A (en) * | 1988-06-27 | 1991-04-02 | Hildinger Henry W | Process for recycling and purifying condensate from a hydrocarbon or alcohol synthesis process |
| DE10150481B4 (en) * | 2001-10-16 | 2020-09-10 | Exxonmobil Chemical Patents Inc. | Process for the production of olefins from methanol |
| US7199276B2 (en) | 2003-11-19 | 2007-04-03 | Exxonmobil Chemical Patents Inc. | Controlling the ratio of ethylene to propylene produced in an oxygenate to olefin conversion process |
| US7196239B2 (en) | 2003-11-19 | 2007-03-27 | Exxonmobil Chemical Patents Inc. | Methanol and ethanol production for an oxygenate to olefin reaction system |
| US7288689B2 (en) | 2003-11-19 | 2007-10-30 | Exxonmobil Chemical Patents Inc. | Methanol and fuel alcohol production for an oxygenate to olefin reaction system |
| DE102006026356A1 (en) * | 2006-05-30 | 2007-12-06 | Süd-Chemie Zeolites GmbH | Process for the catalytic conversion of bio-based organic oxygenated compounds |
| US9255227B2 (en) * | 2006-12-13 | 2016-02-09 | Haldor Topsoe A/S | Process for the synthesis of hydrocarbon constituents of gasoline |
| CN110508315A (en) * | 2019-07-18 | 2019-11-29 | 深圳市燃气集团股份有限公司 | A kind of catalyst for preparing hydrogen by reforming methanol and water vapour and preparation method thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE622595C (en) * | 1923-03-20 | 1935-12-02 | I G Farbenindustrie Akt Ges | Process for the production of methyl alcohol and other oxygen-containing organic compounds |
| CS191916B2 (en) * | 1973-08-09 | 1979-07-31 | Mobil Oil Corp | Method of producing aromatic hydrocarbons |
| US4025576A (en) * | 1975-04-08 | 1977-05-24 | Mobil Oil Corporation | Process for manufacturing olefins |
| FR2369234A1 (en) * | 1976-10-29 | 1978-05-26 | Inst Francais Du Petrole | ALC MANUFACTURING PROCESS |
| PL208467A1 (en) * | 1978-07-15 | 1980-02-25 | Inst Ciezkiej Syntezy Orga | |
| DE2909929A1 (en) * | 1979-03-14 | 1980-09-25 | Basf Ag | METHOD FOR PRODUCING A ZSM-5 STRUCTURAL TYPE |
| DE3005550A1 (en) * | 1980-02-14 | 1981-08-20 | Süd-Chemie AG, 8000 München | METHOD FOR PRODUCING OLEFINS |
| DE3021580A1 (en) * | 1980-06-07 | 1981-12-24 | Basf Ag, 6700 Ludwigshafen | METHOD FOR PRODUCING ZEOLITHES AND USE THEREOF AS CATALYSTS |
-
1981
- 1981-03-25 IN IN168/DEL/81A patent/IN155637B/en unknown
- 1981-03-26 AU AU68793/81A patent/AU6879381A/en not_active Abandoned
- 1981-03-27 NZ NZ196644A patent/NZ196644A/en unknown
- 1981-03-31 ZA ZA00812157A patent/ZA812157B/en unknown
- 1981-04-06 DE DE19813113838 patent/DE3113838A1/en not_active Withdrawn
- 1981-04-10 JP JP5420881A patent/JPS56159286A/en active Pending
- 1981-04-10 CA CA000375248A patent/CA1155463A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4661525A (en) * | 1984-03-28 | 1987-04-28 | Texaco Inc. | Process for producing lower aliphatic alcohols |
| US4607055A (en) * | 1985-07-03 | 1986-08-19 | Texaco Inc. | Aliphatic alcohol production |
| US4607056A (en) * | 1985-07-03 | 1986-08-19 | Texaco Inc. | Mixed aliphatic alcohol production |
| US4616040A (en) * | 1985-07-22 | 1986-10-07 | Texaco Inc. | Production of C2 -C6 aliphatic alcohols |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3113838A1 (en) | 1982-01-07 |
| AU6879381A (en) | 1981-10-15 |
| ZA812157B (en) | 1982-04-28 |
| JPS56159286A (en) | 1981-12-08 |
| NZ196644A (en) | 1983-09-02 |
| IN155637B (en) | 1985-02-16 |
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