CA2130994A1 - Process for producing a gaseous product - Google Patents
Process for producing a gaseous productInfo
- Publication number
- CA2130994A1 CA2130994A1 CA 2130994 CA2130994A CA2130994A1 CA 2130994 A1 CA2130994 A1 CA 2130994A1 CA 2130994 CA2130994 CA 2130994 CA 2130994 A CA2130994 A CA 2130994A CA 2130994 A1 CA2130994 A1 CA 2130994A1
- Authority
- CA
- Canada
- Prior art keywords
- particles
- fluidized bed
- gaseous product
- process according
- separated
- 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.)
- Abandoned
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
- C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
- C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
- C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
- C01B3/38—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
- C01B3/42—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts using moving solid particles
- C01B3/44—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts using moving solid particles using the fluidised bed technique
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
- B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
- B01J8/38—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it
- B01J8/384—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only
- B01J8/388—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only externally, i.e. the particles leaving the vessel and subsequently re-entering it
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Health & Medical Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Inorganic Chemistry (AREA)
- Hydrogen, Water And Hydrids (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Catalysts (AREA)
Abstract
A process for producing a gaseous product is described whereby reactants (e.g. hydrocarbons and steam) are introduced into a fluidized bed operated under conditions such that a reaction takes place in the fluidized bed to produce the gaseous product (e.g synthesis gaz), the fluidized bed comprising particles having a density and size distribution such that at least a portion of the particles are entrained by the gaseous product leaving the fluidized bed, removing the gaseous product and entrained particles from the fluidized bed, substantially separating the particles entrained in the effluent gas from the gaseous product and returning the separated particles to the fluidized bed wherein at least a portion of the energy required for the reaction is supplied by heating the separated particles during their return to the fluidized bed.
Multi-solid fluidized bed processes are also disclosed.
Multi-solid fluidized bed processes are also disclosed.
Description
5~WO93/17958 PCT/AU~3/00099 ~ 1 3 0 ~
PROC~SS F~R PROD~CING A GASEO~S PRO~CT
The present invention relates to processes for producing a gaseous product. In one particular application, ~he invention relates to a process for the steam reforming of hydrocarbons.
Steam reforming of hydrocarbons such as natural gas or naphtha involves reaction with steam to produce a mixture of carbon oxides, hydrogen and water vapour. This gas mixture, common}y referred to as "syngas" in tha petrochemical industry, is the starting point for numerous catalytic synthesis products such as methanol, gssoline and wax. It is also useful for metallurgical reduction processes, production of eleFtrical energy from fuel cells and -production of hydrogen for use in, for example, ammonia synthesis.
The reforming reaction is strongly endothermic and is conYentionally performed at around 800-900C, at pressures of 10 to 30 bar in catalyst-filled, high-alloy tubes. Thes~
tubes are usually 100 to 150mm in diameter and around lOm in length; heat transfer from hot flue gases on the outside of the tubes to the reacting mixture within is a ma~or rate-limiting step in the o~erall process. Thermal driving forces for heat transfer are large and tube layout is dictated, to a large degree, by the need for sufficient radiation view-factors to avoid the formation of hot and cold-spots on the tubes. This results in a need for large furnace volumes and plan areas - a constraint more difficult to accept in some applications than in others.
Numerous proposals to reduce the size of the steam reformer have been developed. For example, US Patent No. 4888131 describes a process whereby a sharp reduction in furnace -~
volume is possible by introducing oxygen into the system.
~.
~9~ ~ 2 -Partial oxidation schemes such as this are useful when oxygen injection is feasible and does not substantially downgrade the quality of the product gas. However, in other application examples (eg ship-board gas conversion operations) it may be undesirable to use oxygen for safety and economic reasons and other means for reducing the volume of the reformer must be considered.
Immersion of catalyst-filled tubes in a fluidized bed, as de~cribed in, for example, British Patent No. 2126118, is an alternative means for reducing the size of an otherwise conventional reformer. In this case heat transfer to the outside of the tubes is achiev~d via the hot par~icles that comprise the fluidized bed. This results in a more even heat distribu~ion and a significant reduction in the space needed between tubes. However, this process does ha~e a number of disadvan~ages including hot erosion of the high-alloy tubes and unsuitability for ship-board applications, where wave motion can affect the integrity of the tubes.
US Patent No. 3524819 describes a process in which a mixture of hydrocarbons and steam is reformed in an internal-free fluidized bed of fine-grained catalyst. Heat for the reforming reaction is provided by continuously withdrawing a portion of the catalyst and heating this catalyst by contact wi~h hot flue gases before returning it to the reforming bed.
Howe~er, this process exposes the catalyst (in bulk) to high temperatures which may cause the catalyst to sinter, thereby losing catalytic activity and requiring rapid (and costly) replacem~nt.
Hence, an ob~ect of the present invention is to provide an alternative prscess utilising fluidized bed technology, which may permit a reduction in the size of the steam reforming plant.
U ~ ~ ~ O ~ ~ 9 9 ~E~ 2 AU6 l~S3 3 ~ 1 3 0 .'3 .~ ~
Thus, according to a first aspect, the present invention .
provides a process for producing a gaseous product comprising passing reactants into a fluidized bed operated under conditions such that a reaction takes place to produce the gaseous product, the fluidized bed comprising first particles having a density and size distribution such that at least a portion of the first particles are entrained by the gaseous product leaving the fluidized bed and second particles having a density and size distribution such that said second particles substantially remain in the fluidized bed, substantially removing the gaseous product and entrained first particles from the fluidized bed, separating the first ~-particles entrained in the gaseous product from the gaseous product and returning the separated first particles to the fluidized bed wherein at least a portion of the energy :~
required for the reaction is supplied by heating the separated first particles during their return to the fluidized bed. ~.
The separated first par~icles are preferably heated by passing the particles through a chamber where fuel gas or the like is combusted. The separated first particles may be :~
cat~lytic, but more preferably they are inert.
'.
'~
. . .
~CT~AU 9 3 / O O O 9 9 . .
~ .
4~130g9 ~
It may be appreciated that in the process according to the invention, a minor portion of second particles may escape the fluidized bed by entrainment in the gaseous product. When the second particles are catalytically active, such "escapes"
will result in a loss of catalyst. To avoid this loss, it is preferable that following separation of the particles from the gaseous product and prior to the first particles being subjected to heating, any second particles are substantially separated from the first particles and returned to the fluidized bed. This arrangement also permits the fluidized bed to be operated such that an amount of a mixture of first and second particles i5 normally entrained in the gaseous product.
Thus, in a second aspect, the present invention provides a process for producing a gaseous product comprising passing reactants into a fluidized bed operated under conditions such that a reaction takes: place to produce a gaseous product, the fluidized bed comprising f irst and second particles having density and size distributions such that at least a portion of both first and second particles are entrained by the gaseous product leaving the fluidized bed, removing the gaseous product and entrained first and second particles from the fluidized bed, separating the first and second particles ~entrained in the gaseous product from the gaseous product, substantially separating the first and second particles, and thereafter separately returning the separated first particles and separated second particles to the fluidized bed wherein at least a portion of the energy required for the reaction is supplied by heating the separated first particles during their return to the fluidized bed.
ILEAlsu~TuTF SH~
~ W093/1795~ LJ P~T/AU93/00099 . ~
The surface area of the first particles is not critical~
However, the first particles are preferably catalytically inert. Examples of suitable materials include but are not limited to dense alumina, zirconia, rutile, metals such as -nicksl or mixtures thereof. The second particles are preferably catalytieally active.
The first and second particles may be separated by a fluidized bed segregator. :~
~.
I~ will be appreciated that the fluidized bed reactor and a~30c~ated equipment to facilitate the separation and return of particles entrained in the gaseous product comprise a circulating fluidized bed system.
The prbcess according to the inven~ion may be suitable for a number of h~at driven reactions including pyrolysis :~;
reactions, nap~ha cracking, ethane con~ersion to ethane and maleic anhydride synthesis. H~we~er, the proce~ses are particularly ~uitable for steam reforming of hydrocarbons to produce a gaseous product containing hydrogen and carbon oxides. Accordingly, the invention is hereinafter described in relation to this application.
':
In this application of the inYention, the reactants are hydrocarbons and steam and the fluidized bed is operated ;:
under conditions such that a steam reforming reaction ~akes place. r~
The flsidized bed reformer may be operated at a temperature from 750 to 950C preferably in the range of 800 to 900C
and at a presBure in the range of 5 to 80 bar, praferably 10 to 30 bar.
: .
The first particles are preferably catalytically inert and haYe a maximum particle size of less than about 0.5mm with an WO93/17958 PCT/AU~3/000~9 :-~ 1 3~9!~
average particle size preferably lying in the range of about O.03 to 0.3mm. ~-The second particles are preferably catalytically active and may have a function and chemical composition typical of known steam reforming catalysts (e.g. ~i or Ru supported on alumina, calcium alumnate or ~irconia~. The~e particles may be porous and display high catalytic activity for the steam reforming reaction. Average par~icle size preferably lies in the range of 0.7 to 7mm with little or no material smaller ~:
in size than 0.Smm. ;~
The suspension density of the reformer vessel may be about 200 to 2000 kg/m3, preferably about 1000 to 1800kg/m3.
The separated particles are preferably heated to a tempersture of about 950 to 1200C, preferably about 1000 to 1100C during their retuxn to the fluidized bed reformer.
The invention is further described by way of the following non-limiting examples and with ref~rence to Figures 1 and 2. --Figure~ 1 and 2 provide diagrammatic repre~entations of apparatus suitable for performing the process of the present ~.^
inYention. : :~
A mixture of hydrocarbons (natural gas or higher hydrocarbons such as ethane or naphtha) and steam 101 is pre-heat~d in -heat exchanger 102 before being fed into the bottom of the fluidized bed reformsr 103. Unit 103 contains a dense-phase fluidized bed with two types of particle present:
i) a component which is catalytically acti~e, similar in structure and pu~pose to con~entional alumina-supported Ni catalysts le.g. ICI 57-s~ries catalysts). These ` W093/17958 PCT/AU93/00099 , _ 7 _ ~1 3 0~
particles may be porous and display high catalytic activity for the steam reforming reaction. A~erage particle size lies in the range 0.7 to 7mm, with little or no material smaller in size than 0.5mm.
ii) A component (e.g. fused alumina) which has low specific surface area and is catalytically inert. This component of the population is smaller in size than the catalytically active component, all particles being smaller than 0~5mm and average size for the inert component lying in the range 0.03 to 0.3mm.
Fluidized bed reformer 103 is operated surh that ths fine, inert component of the particle population is preferentially entrained from the top of ~he vessel while the coarse, catalytic component remains in the ve sel. Steam reforming takes place within vessel 103 at a temperature of about 850C
and a pressure in the range 10 ~o 30 bar. Effluent gas 104, along with entrained fine solids, en~ers cyclone 105. ~ulk disengagement occurs and the cyclone oYerhead stream enters hot gas cleaner 106. In this unit the bulk of the remaining solid is removed by, for example, a hot multicyclone system.
Cleaned gas 107 leaves the cleaning unit 106 and passes to heat exchanger 102 before being scrubbed and passed on for use downstream.
Solids from the underflow of cyclone 10~ are fed, Yia pressure recovery system such as loopseal 108, to chamber 103 where fuel gas ~nd air are combusted at a pressure similar ~o tha~ in vessel 103. Solids are heated from 800-850 C to around 1000-1100 C and are subsequently remo~ed from the hot flue gases in cyclo~e 110. From here the hot solids are returned to the base of the reforming vessel 103 via pressure recovery system 111 to pro~ided the heat necessary for the reforming reaction. The bottom inlet system for hot solids is designed to ensure a larg~ mass flux of bed material is WO93/17958 PCT~AU93/0009~ .
~9~ 8 -available to rapidly dilute the hot solids stream, thereby avoiding the exposure of catalytically active particles to (destructive) high temperatures.
.
Hot, pressurised flue gas from the overflow of cyclone 110 is used for energy recovery purposes. Hot gas cleaning is carried out in unit 112, the precise form of which is not critical. Partial cooling (to 800C for example) followed by a micro-cyclone system may be used, or a ceramic barrier-filter system similar to those currently under dPvelopment for pressuxised fluidized bed combustion and gasification. The cleaned gas is subsequPntly expanded ~hrough turbine 113. From here it is subjected to further heat recovery and finally vented.
:
EX~NPLE 2 .
A mixture of hydrocarbons ~natural gas or higher hydrocarbons such as ethane or naptha) and steam 20} is pr~-heated in heat exchanger 202 before being fed into the bottom of a fluidized bed reformer 203. Unit 203 contains a dense-phase fluidized bed with two types of particles as described in Example 1~
Steam reforming takes place within vessel 203 again at a temperature of about 850 C and a pressure in the range 10 to 30 bar. However, in this case the fluidized bed reformer 203 is operated such that a mixture of bed solids are entrained in gas leaving the vessel. Effluent gas 204, along with entrained solids, enters cyclone 205. Bulk di~engagement occurs and the cyclone overhead stream !enters hot gas clean~r 206 where the bulk of the remaining solid is removed by, for example, a hot multicyclone system. Cleaned gas 207 leaves the cleaning unit 206 and passes to heat exchanger 202 before being scrubbed and passed on for use downstream ~WO93/17958 l1 3 Q g g -~ PCT/AU93/00099 Solids from cyclone 205 are fed to fluidized.bed segregator 208. Unit 208 contains a low velocity bubbling fluid-zed bed within which the coarse ~catalytically active) particles preferentially sink to the bottom and are returned, along with some fine heat-carrier solids, to unit 203. The fluidizing gas for unit 20~ may be any convenient gas, but is preferentially steam or fuel gas.
Fine heat-carrier solids, substantially free of coarse (catalytically active) solids, leave the top of unit 208 and enter unit 20g where fuel gas and air are combusted at a pressure similar to ~hat in vessel 203. Solids are heated from 800 -850 C to around 1000 -1100 C and are subsequently removed from the hot ~lue gases in cyclone 210.
From here the hot solids are returned to the base of reforming vessel 203 ~ia pressure recovery system 211 to pro~ide the heat necessary for the reforming reaction.
Hot, pressurised flue gas from the overflow of cyclone 210 i3 us~d for energy recovery purposes. ~ot gas cleaning is carried out in unit 212. Partial cooling (to 800 C for example) followed by a micro-cyclone system or a ceramic barrier-~ilter system may be used. The cleaned gas is subsequently expanded through turbine 213, after which it may be subjected to further heat recovery and finally vented.
The present invention offers a compact system, that may be opexated free of the need for oxygen, for application to processing in situations such as shipboard reforming. The reforming vessel itself is free of expensive, high-maintenance tubes of high-alloy metal and associated maintenance and safety issues arising from wave motion. It may be configured to avoid substantial exposure of catalyst particles to high temperatures which would otherwise promote sintering, thereby achieving good catalyst utilisation.
~ 13~99 ~ lO
Those skilled in the art will appreciate that the invention ~
described herein is susceptible to variations and ~:
modifications other than those specifically descxibed. It is therefore to be understood that the invention includes all such variations and modifications which fall within its spirit and scope.
PROC~SS F~R PROD~CING A GASEO~S PRO~CT
The present invention relates to processes for producing a gaseous product. In one particular application, ~he invention relates to a process for the steam reforming of hydrocarbons.
Steam reforming of hydrocarbons such as natural gas or naphtha involves reaction with steam to produce a mixture of carbon oxides, hydrogen and water vapour. This gas mixture, common}y referred to as "syngas" in tha petrochemical industry, is the starting point for numerous catalytic synthesis products such as methanol, gssoline and wax. It is also useful for metallurgical reduction processes, production of eleFtrical energy from fuel cells and -production of hydrogen for use in, for example, ammonia synthesis.
The reforming reaction is strongly endothermic and is conYentionally performed at around 800-900C, at pressures of 10 to 30 bar in catalyst-filled, high-alloy tubes. Thes~
tubes are usually 100 to 150mm in diameter and around lOm in length; heat transfer from hot flue gases on the outside of the tubes to the reacting mixture within is a ma~or rate-limiting step in the o~erall process. Thermal driving forces for heat transfer are large and tube layout is dictated, to a large degree, by the need for sufficient radiation view-factors to avoid the formation of hot and cold-spots on the tubes. This results in a need for large furnace volumes and plan areas - a constraint more difficult to accept in some applications than in others.
Numerous proposals to reduce the size of the steam reformer have been developed. For example, US Patent No. 4888131 describes a process whereby a sharp reduction in furnace -~
volume is possible by introducing oxygen into the system.
~.
~9~ ~ 2 -Partial oxidation schemes such as this are useful when oxygen injection is feasible and does not substantially downgrade the quality of the product gas. However, in other application examples (eg ship-board gas conversion operations) it may be undesirable to use oxygen for safety and economic reasons and other means for reducing the volume of the reformer must be considered.
Immersion of catalyst-filled tubes in a fluidized bed, as de~cribed in, for example, British Patent No. 2126118, is an alternative means for reducing the size of an otherwise conventional reformer. In this case heat transfer to the outside of the tubes is achiev~d via the hot par~icles that comprise the fluidized bed. This results in a more even heat distribu~ion and a significant reduction in the space needed between tubes. However, this process does ha~e a number of disadvan~ages including hot erosion of the high-alloy tubes and unsuitability for ship-board applications, where wave motion can affect the integrity of the tubes.
US Patent No. 3524819 describes a process in which a mixture of hydrocarbons and steam is reformed in an internal-free fluidized bed of fine-grained catalyst. Heat for the reforming reaction is provided by continuously withdrawing a portion of the catalyst and heating this catalyst by contact wi~h hot flue gases before returning it to the reforming bed.
Howe~er, this process exposes the catalyst (in bulk) to high temperatures which may cause the catalyst to sinter, thereby losing catalytic activity and requiring rapid (and costly) replacem~nt.
Hence, an ob~ect of the present invention is to provide an alternative prscess utilising fluidized bed technology, which may permit a reduction in the size of the steam reforming plant.
U ~ ~ ~ O ~ ~ 9 9 ~E~ 2 AU6 l~S3 3 ~ 1 3 0 .'3 .~ ~
Thus, according to a first aspect, the present invention .
provides a process for producing a gaseous product comprising passing reactants into a fluidized bed operated under conditions such that a reaction takes place to produce the gaseous product, the fluidized bed comprising first particles having a density and size distribution such that at least a portion of the first particles are entrained by the gaseous product leaving the fluidized bed and second particles having a density and size distribution such that said second particles substantially remain in the fluidized bed, substantially removing the gaseous product and entrained first particles from the fluidized bed, separating the first ~-particles entrained in the gaseous product from the gaseous product and returning the separated first particles to the fluidized bed wherein at least a portion of the energy :~
required for the reaction is supplied by heating the separated first particles during their return to the fluidized bed. ~.
The separated first par~icles are preferably heated by passing the particles through a chamber where fuel gas or the like is combusted. The separated first particles may be :~
cat~lytic, but more preferably they are inert.
'.
'~
. . .
~CT~AU 9 3 / O O O 9 9 . .
~ .
4~130g9 ~
It may be appreciated that in the process according to the invention, a minor portion of second particles may escape the fluidized bed by entrainment in the gaseous product. When the second particles are catalytically active, such "escapes"
will result in a loss of catalyst. To avoid this loss, it is preferable that following separation of the particles from the gaseous product and prior to the first particles being subjected to heating, any second particles are substantially separated from the first particles and returned to the fluidized bed. This arrangement also permits the fluidized bed to be operated such that an amount of a mixture of first and second particles i5 normally entrained in the gaseous product.
Thus, in a second aspect, the present invention provides a process for producing a gaseous product comprising passing reactants into a fluidized bed operated under conditions such that a reaction takes: place to produce a gaseous product, the fluidized bed comprising f irst and second particles having density and size distributions such that at least a portion of both first and second particles are entrained by the gaseous product leaving the fluidized bed, removing the gaseous product and entrained first and second particles from the fluidized bed, separating the first and second particles ~entrained in the gaseous product from the gaseous product, substantially separating the first and second particles, and thereafter separately returning the separated first particles and separated second particles to the fluidized bed wherein at least a portion of the energy required for the reaction is supplied by heating the separated first particles during their return to the fluidized bed.
ILEAlsu~TuTF SH~
~ W093/1795~ LJ P~T/AU93/00099 . ~
The surface area of the first particles is not critical~
However, the first particles are preferably catalytically inert. Examples of suitable materials include but are not limited to dense alumina, zirconia, rutile, metals such as -nicksl or mixtures thereof. The second particles are preferably catalytieally active.
The first and second particles may be separated by a fluidized bed segregator. :~
~.
I~ will be appreciated that the fluidized bed reactor and a~30c~ated equipment to facilitate the separation and return of particles entrained in the gaseous product comprise a circulating fluidized bed system.
The prbcess according to the inven~ion may be suitable for a number of h~at driven reactions including pyrolysis :~;
reactions, nap~ha cracking, ethane con~ersion to ethane and maleic anhydride synthesis. H~we~er, the proce~ses are particularly ~uitable for steam reforming of hydrocarbons to produce a gaseous product containing hydrogen and carbon oxides. Accordingly, the invention is hereinafter described in relation to this application.
':
In this application of the inYention, the reactants are hydrocarbons and steam and the fluidized bed is operated ;:
under conditions such that a steam reforming reaction ~akes place. r~
The flsidized bed reformer may be operated at a temperature from 750 to 950C preferably in the range of 800 to 900C
and at a presBure in the range of 5 to 80 bar, praferably 10 to 30 bar.
: .
The first particles are preferably catalytically inert and haYe a maximum particle size of less than about 0.5mm with an WO93/17958 PCT/AU~3/000~9 :-~ 1 3~9!~
average particle size preferably lying in the range of about O.03 to 0.3mm. ~-The second particles are preferably catalytically active and may have a function and chemical composition typical of known steam reforming catalysts (e.g. ~i or Ru supported on alumina, calcium alumnate or ~irconia~. The~e particles may be porous and display high catalytic activity for the steam reforming reaction. Average par~icle size preferably lies in the range of 0.7 to 7mm with little or no material smaller ~:
in size than 0.Smm. ;~
The suspension density of the reformer vessel may be about 200 to 2000 kg/m3, preferably about 1000 to 1800kg/m3.
The separated particles are preferably heated to a tempersture of about 950 to 1200C, preferably about 1000 to 1100C during their retuxn to the fluidized bed reformer.
The invention is further described by way of the following non-limiting examples and with ref~rence to Figures 1 and 2. --Figure~ 1 and 2 provide diagrammatic repre~entations of apparatus suitable for performing the process of the present ~.^
inYention. : :~
A mixture of hydrocarbons (natural gas or higher hydrocarbons such as ethane or naphtha) and steam 101 is pre-heat~d in -heat exchanger 102 before being fed into the bottom of the fluidized bed reformsr 103. Unit 103 contains a dense-phase fluidized bed with two types of particle present:
i) a component which is catalytically acti~e, similar in structure and pu~pose to con~entional alumina-supported Ni catalysts le.g. ICI 57-s~ries catalysts). These ` W093/17958 PCT/AU93/00099 , _ 7 _ ~1 3 0~
particles may be porous and display high catalytic activity for the steam reforming reaction. A~erage particle size lies in the range 0.7 to 7mm, with little or no material smaller in size than 0.5mm.
ii) A component (e.g. fused alumina) which has low specific surface area and is catalytically inert. This component of the population is smaller in size than the catalytically active component, all particles being smaller than 0~5mm and average size for the inert component lying in the range 0.03 to 0.3mm.
Fluidized bed reformer 103 is operated surh that ths fine, inert component of the particle population is preferentially entrained from the top of ~he vessel while the coarse, catalytic component remains in the ve sel. Steam reforming takes place within vessel 103 at a temperature of about 850C
and a pressure in the range 10 ~o 30 bar. Effluent gas 104, along with entrained fine solids, en~ers cyclone 105. ~ulk disengagement occurs and the cyclone oYerhead stream enters hot gas cleaner 106. In this unit the bulk of the remaining solid is removed by, for example, a hot multicyclone system.
Cleaned gas 107 leaves the cleaning unit 106 and passes to heat exchanger 102 before being scrubbed and passed on for use downstream.
Solids from the underflow of cyclone 10~ are fed, Yia pressure recovery system such as loopseal 108, to chamber 103 where fuel gas ~nd air are combusted at a pressure similar ~o tha~ in vessel 103. Solids are heated from 800-850 C to around 1000-1100 C and are subsequently remo~ed from the hot flue gases in cyclo~e 110. From here the hot solids are returned to the base of the reforming vessel 103 via pressure recovery system 111 to pro~ided the heat necessary for the reforming reaction. The bottom inlet system for hot solids is designed to ensure a larg~ mass flux of bed material is WO93/17958 PCT~AU93/0009~ .
~9~ 8 -available to rapidly dilute the hot solids stream, thereby avoiding the exposure of catalytically active particles to (destructive) high temperatures.
.
Hot, pressurised flue gas from the overflow of cyclone 110 is used for energy recovery purposes. Hot gas cleaning is carried out in unit 112, the precise form of which is not critical. Partial cooling (to 800C for example) followed by a micro-cyclone system may be used, or a ceramic barrier-filter system similar to those currently under dPvelopment for pressuxised fluidized bed combustion and gasification. The cleaned gas is subsequPntly expanded ~hrough turbine 113. From here it is subjected to further heat recovery and finally vented.
:
EX~NPLE 2 .
A mixture of hydrocarbons ~natural gas or higher hydrocarbons such as ethane or naptha) and steam 20} is pr~-heated in heat exchanger 202 before being fed into the bottom of a fluidized bed reformer 203. Unit 203 contains a dense-phase fluidized bed with two types of particles as described in Example 1~
Steam reforming takes place within vessel 203 again at a temperature of about 850 C and a pressure in the range 10 to 30 bar. However, in this case the fluidized bed reformer 203 is operated such that a mixture of bed solids are entrained in gas leaving the vessel. Effluent gas 204, along with entrained solids, enters cyclone 205. Bulk di~engagement occurs and the cyclone overhead stream !enters hot gas clean~r 206 where the bulk of the remaining solid is removed by, for example, a hot multicyclone system. Cleaned gas 207 leaves the cleaning unit 206 and passes to heat exchanger 202 before being scrubbed and passed on for use downstream ~WO93/17958 l1 3 Q g g -~ PCT/AU93/00099 Solids from cyclone 205 are fed to fluidized.bed segregator 208. Unit 208 contains a low velocity bubbling fluid-zed bed within which the coarse ~catalytically active) particles preferentially sink to the bottom and are returned, along with some fine heat-carrier solids, to unit 203. The fluidizing gas for unit 20~ may be any convenient gas, but is preferentially steam or fuel gas.
Fine heat-carrier solids, substantially free of coarse (catalytically active) solids, leave the top of unit 208 and enter unit 20g where fuel gas and air are combusted at a pressure similar to ~hat in vessel 203. Solids are heated from 800 -850 C to around 1000 -1100 C and are subsequently removed from the hot ~lue gases in cyclone 210.
From here the hot solids are returned to the base of reforming vessel 203 ~ia pressure recovery system 211 to pro~ide the heat necessary for the reforming reaction.
Hot, pressurised flue gas from the overflow of cyclone 210 i3 us~d for energy recovery purposes. ~ot gas cleaning is carried out in unit 212. Partial cooling (to 800 C for example) followed by a micro-cyclone system or a ceramic barrier-~ilter system may be used. The cleaned gas is subsequently expanded through turbine 213, after which it may be subjected to further heat recovery and finally vented.
The present invention offers a compact system, that may be opexated free of the need for oxygen, for application to processing in situations such as shipboard reforming. The reforming vessel itself is free of expensive, high-maintenance tubes of high-alloy metal and associated maintenance and safety issues arising from wave motion. It may be configured to avoid substantial exposure of catalyst particles to high temperatures which would otherwise promote sintering, thereby achieving good catalyst utilisation.
~ 13~99 ~ lO
Those skilled in the art will appreciate that the invention ~
described herein is susceptible to variations and ~:
modifications other than those specifically descxibed. It is therefore to be understood that the invention includes all such variations and modifications which fall within its spirit and scope.
Claims (18)
1. A process for producing a gaseous product comprising passing reactants into a fluidized bed operated under conditions such that a reaction takes place to produce the gaseous product, the fluidized bed comprising first particles having a density and size distribution such that at least a portion of the first particles are entrained by the gaseous product leaving the fluidized bed and second particles having a density and size distribution such that said second particles substantially remain in the fluidized bed, removing the gaseous product and entrained first particles from the fluidized bed, substantially separating the first particles entrained in the gaseous product from the gaseous product and returning the separated first particles to the fluidized bed wherein at least a portion of the energy required for the reaction is supplied by heating the separated first particles during their return to the fluidized bed.
2. A process for producing a gaseous product comprising passing reactants into a fluidized bed operated under conditions such that a reaction takes place to produce the gaseous product, the fluidized bed comprising first and second particles having density and size distributions such that at least a portion of both first and second particles are entrained by the gaseous product leaving the fluidized bed, removing the gaseous product and entrained first and second particles from the fluidized bed, substantially separating the first and second particles entrained in the gaseous product from the gaseous product, substantially separating the first and second particles, and thereafter separately returning the separated first particles and separated second particles to the fluidized bed wherein at least a portion of the energy required for the reaction is supplied by heating the separated first particles during their return to the fluidized bed.
3. A process according to claim 1 or 2 wherein the first particles are catalytically inert.
4. A process according to claim 3 wherein the first particles are particles of one or more of alumina, zirconia, rutile or nickel.
5. A process according to any one of claims 1 to 4 wherein the second particles are solid catalyst.
6. A process according to any one of claims 1 to 5 wherein the reactants are hydrocarbons and steam and the fluidized bed is operated under conditions such that a steam reforming reaction takes place in the fluidized bed to produce a gaseous product containing hydrogen and carbon oxides.
7. A process according to claim 6 wherein the first particles are of a size less than about 0.5mm.
8. A process according to claim 7 wherein the first particles are in the size range of about 0.03 to 0.3mm.
9. A process according to any one of claims 6 to 8 wherein the average size of the second particles is in the range of about 0.7 to 7.0mm.
10. A process according to claim 9 wherein the second particles have a function and chemical composition typical of steam reforming catalysts.
11. A process according to any one of claims 6 to 10 wherein the separated first particles are heated to about 950 to 1200°C during their return to the fluidized bed.
12. A process according to claim 11 wherein the first particles are heated to about 1000 to 1100°C during their return to the fluidized bed.
13. A process according to any one of the preceding claims wherein the first and second particles are separated by a fluidized bed segregator.
14. A process according to any one of the preceding claims wherein the fluidized bed has a suspension density of about 200 to 2000 kg/m3.
15. A process according to claim 14 wherein the fluidized bed has a suspension density of about 1000 to 1800 kg/m3.
16. A process according to any one of the preceding claims wherein the heated separated particles are returned to the fluidized bed via an inlet located at the base of the fluidized bed.
17. An apparatus when used with a process according to any of the preceding claims.
18. A process substantially as described with reference to example 1 or 2.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPL1240 | 1992-03-06 | ||
| AUPL124092 | 1992-03-06 | ||
| AUPL349392 | 1992-07-14 | ||
| AUPL3493 | 1992-07-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2130994A1 true CA2130994A1 (en) | 1993-09-16 |
Family
ID=25644204
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2130994 Abandoned CA2130994A1 (en) | 1992-03-06 | 1993-03-05 | Process for producing a gaseous product |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0629176A4 (en) |
| JP (1) | JPH07505570A (en) |
| CA (1) | CA2130994A1 (en) |
| NO (1) | NO943113D0 (en) |
| NZ (1) | NZ249452A (en) |
| WO (1) | WO1993017958A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1318796C (en) * | 2004-07-26 | 2007-05-30 | 中国科学院工程热物理研究所<Del/> | Method for producing both gas and steam, and boiler of circulating fluid bed with pyrolysis vaporizer |
| WO2008082312A1 (en) * | 2007-01-05 | 2008-07-10 | Sinvent As | Hydrogen production |
| JP4835581B2 (en) * | 2007-11-14 | 2011-12-14 | 株式会社Ｉｈｉ | Circulating fluidized bed reformer |
| JP2009298618A (en) * | 2008-06-11 | 2009-12-24 | Ihi Corp | Apparatus and method for reforming organic compound |
| JP7118341B2 (en) * | 2020-08-07 | 2022-08-16 | 株式会社堤水素研究所 | Hydrogen production equipment |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2523284A (en) * | 1945-08-17 | 1950-09-26 | Texas Co | Method of manufacturing hydrogen and carbon monoxide |
| US2448922A (en) * | 1946-01-23 | 1948-09-07 | Socony Vacuum Oil Co Inc | Continuous cracking process |
| US2783133A (en) * | 1952-12-05 | 1957-02-26 | Socony Mobil Oil Co Inc | Hydrogen production |
| US2875150A (en) * | 1953-11-12 | 1959-02-24 | Hydrocarbon Research Inc | Heavy oil conversion with low coke formation |
| US3342561A (en) * | 1963-01-22 | 1967-09-19 | Universal Oil Prod Co | System for hydrogen production by catalytic decomposition of a hydrocarbon stream |
| US3573224A (en) * | 1967-11-14 | 1971-03-30 | Chemical Construction Corp | Production of hydrogen-rich synthesis gas |
| JPS5575901A (en) * | 1978-11-30 | 1980-06-07 | Nippon Kokan Kk <Nkk> | Production of reducing gas |
| DE3680122D1 (en) * | 1985-02-13 | 1991-08-14 | Shell Int Research | METHOD FOR GENERATING A HYDROGEN-CONTAINING GAS FROM HYDROCARBONS, WATER VAPOR AND / GGF. CARBON DIOXIDE. |
| HU9201539D0 (en) * | 1990-09-11 | 1992-08-28 | Kortec Ag | Method and device for gasifying gasifiable materials and/or transforming gas as well as heat exchanger of high temperature for executing said method |
| US5160456A (en) * | 1991-06-07 | 1992-11-03 | Exxon Research And Engineering Company | Catalyst/heat-transfer medium for syngas generation |
-
1993
- 1993-03-05 WO PCT/AU1993/000099 patent/WO1993017958A1/en not_active Application Discontinuation
- 1993-03-05 CA CA 2130994 patent/CA2130994A1/en not_active Abandoned
- 1993-03-05 JP JP5515185A patent/JPH07505570A/en active Pending
- 1993-03-05 EP EP93905114A patent/EP0629176A4/en not_active Withdrawn
- 1993-03-05 NZ NZ24945293A patent/NZ249452A/en unknown
-
1994
- 1994-08-23 NO NO943113A patent/NO943113D0/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| NZ249452A (en) | 1996-01-26 |
| NO943113L (en) | 1994-08-23 |
| NO943113D0 (en) | 1994-08-23 |
| EP0629176A4 (en) | 1995-11-22 |
| JPH07505570A (en) | 1995-06-22 |
| EP0629176A1 (en) | 1994-12-21 |
| WO1993017958A1 (en) | 1993-09-16 |
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