CA1296023C - Process for converting a gaseous feed into an at least partly liquidproduct - Google Patents
Process for converting a gaseous feed into an at least partly liquidproductInfo
- Publication number
- CA1296023C CA1296023C CA000542731A CA542731A CA1296023C CA 1296023 C CA1296023 C CA 1296023C CA 000542731 A CA000542731 A CA 000542731A CA 542731 A CA542731 A CA 542731A CA 1296023 C CA1296023 C CA 1296023C
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- reaction zone
- zone
- product
- tube
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- 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
- B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
- B01J8/0285—Heating or cooling the reactor
-
- 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
- B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
- B01J8/0207—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid flow within the bed being predominantly horizontal
- B01J8/0214—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid flow within the bed being predominantly horizontal in a cylindrical annular shaped bed
-
- 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
- B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
- B01J8/04—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds
- B01J8/0403—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid passing successively through two or more beds the fluid flow within the beds being predominantly horizontal
-
- 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
- C07C1/02—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon
- C07C1/04—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon from carbon monoxide with hydrogen
- C07C1/0405—Apparatus
- C07C1/042—Temperature controlling devices; Heat exchangers
-
- 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
- B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
- B01J2208/00008—Controlling the process
- B01J2208/00017—Controlling the temperature
- B01J2208/00106—Controlling the temperature by indirect heat exchange
- B01J2208/00115—Controlling the temperature by indirect heat exchange with heat exchange elements inside the bed of solid particles
- B01J2208/00132—Tubes
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Fluid Mechanics (AREA)
- Physics & Mathematics (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Chemical Vapour Deposition (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
Abstract
A B S T R A C T
PROCESS FOR CONVERTING A GASEOUS FEED INTO AN
AT LEAST PARILY LIQUID PRODUCT
A process for converting a gaseous feed (e.g. synthesis gas) into an at least partly liquid product (e.g. paraffins) by introducing said feed into at least one reaction zone which is maintained at conversion conditions, allowing the feed to flow substantially radially towards a product collection zone, and remcving liquid- and gaseous product from the reaction zone through the collection zone.
PROCESS FOR CONVERTING A GASEOUS FEED INTO AN
AT LEAST PARILY LIQUID PRODUCT
A process for converting a gaseous feed (e.g. synthesis gas) into an at least partly liquid product (e.g. paraffins) by introducing said feed into at least one reaction zone which is maintained at conversion conditions, allowing the feed to flow substantially radially towards a product collection zone, and remcving liquid- and gaseous product from the reaction zone through the collection zone.
Description
~ 1 --P~DCESS FOR CO~VERTING A G~SEOUS FEED INIO AN
AT LE~ST PARTLY LIQUID PRODUCT
The invention relates to a process for converting a gaseous feed into an at least partly liquid product.
In known processes wherein (partly) liquid products are prepared at the conditions prevailing in the reaction zone, in most cases gravity flQw of the liquid products tcwards the bottom of said zone is employed to collect and remove said products.
A problem associated with such processes is that the pressure drGp over the reaction zo~e is usually relatively large, especially when the reaction zone is filled with particulate (catalyst) material, which makes it unattractive to apply relatively high space velocities in said zone~ Morecver, temperature control in case of exothermic reactions is sc~etimes difficult, unless special measures are taken to prevent this; one of such measures comprises carrying out the process in a plurality (sometimes even more than l000) of tubular reaction zones.
Surprisingly, it has now been fsund that the afore-mentioned problems can be overccme by applying a radial flow regime inside the preferably substantially cylindrical xeaction zone of a normally substantially vertically extending reactor, ~ notwithstanding the presence of liquid product therein, and remc~ing liquid- and gaseous product (including unconverted gaseous feed) toge*her frc~ the reaction zone.
The invention therefore relates to a process for converting a gaseous feed into an at least partly liquid product which ccmprises ; 25 ~ introducing the;gaseous feed into at least one reaGtion zone which is nadntained at conversion conditions, allowing said feed to flow substantially radially towards a product collection zone, and removing liquid- and gaseous product tcgether frcm the reaction Qne through the collection zone.
Processes~and apparatuses in which a radial flow is maintained in the reaction zone are known fQr gas phase reactions such as the : ~ , preparation of methanol or low-boiling hydrocarbons from synthesis gas.
A major advantage of the process according to the invention is that the temperature inside the reaction zone can be optimally controlled by passing the gaseous feed with a relatively high velocity through said æone, which now becomes attractive because the pressure drop over the reaction zone is relatively ~ow. Conse-quently, recycling of liquid produ~t thro~1gh the reaction zone(s3 as sometimes applied in order to maintain te~perature stability therein, in particular when the process is highly exothermic, is not necessary.
Furthermore, it now becomes feasible to operate a process in which liquid product is formed in stacked reaction zones without incurring excessive pressure drop over the zones, due to the fact that the length of the flcw paths through the reaction zones remains substantially equal independent of the number of said zones.
Preferably, the process according to the invention is carried out in such a r~anner that the gaseous feed flows inwardly tcwards the product collection zone arranged substantially centrally inside tha reaction zone(s); this set-up is preferred because the volume of gas flowing towards the collective zone diminishes with the gradual formation of li~uid products resulting in a decrease in space velocity, which decrease is at least partly compensated by the decreasing area through which the gas flows tcwards the central collection zone.
Alternatively, the process according to the invention is carried out with radial outward flow of gaseous feed i~troduced into the reaction zone(s) via feed inlet means arranged centrally in said zone(s~, employing e.g. an annular collection zone which laterally surrounds the reaction zone(s). It is also poss~ble to apply at least one reaction zone with inward flcw in ccmbination with at least one reaction zone with outward flcw.
The radial flow velocity of the ccmbined gaseous feed and -product stream is preferably maintained at a value sufficient to 3~ 3 allow at least a major part (i.e. more than 50% by weight, and most preferably substantially all) of the liquid product to be removed frcm the reaction zone(s) by said stream ln order to avoid non-radial flcw therein.
The present process is particularly suited for catalytic (especially exothermic) conversions, in which case the reaction zone(s) contain(s) at least one catalyst bed. It is also possible to carry out the process in a plurality of stacked catalyst beds which may contain the same or different catalysts. Moreover, each catalyst bed may contain at least two (e.g. annular) zones comprising the same or diferent catalysts.
Heat produced in the catalyst bed(s) can be rem~ved in some cases simply by mainta~ning in the reaction zone(s) an adequate space velocity of the gaseous feed. ~cwever, in many cases it will lS be highly desirable to incorporate at least one heat exchange zone in the reaction zone(s), preferably in the form of heat exchange tubes through which a cooling fluid (e.g. water and/or steam) is led.
The radial flow pattern in the reaction zone(s) results in excellent heat transfer to the heat exchange zones e~en at relative-ly low gas velocities, in particular when heat exchange tubes are arranged in the reaction zone(s) substantially parallel to a central, preferably perforated, collection tube, more particular when the heat exchange zones are arranged in concentric rings.
It is particularly preferred to use one or more heat exchange means situated in a concentric ring or a numb.er of concentric rings around the central supply or collection tube in the form of helical wound tubes or tube bundles, each tube bundle comprising two or more helical wound tubes of substantially the same dimensions.
mus, the cooling medium flows via one or more helical patternssituated concentrically æound the central supply or collection tube, each pattern containing one or more helixes. When two or more concentrical tubes or tube bundles are used, the screw-direction of the helixes of two adjacent tubes or tube bundles is preferably opposite to each other. When two or more tu`be bundles are used it is preferred to use an increasing number of helical wound tubes in 1~361 2,3 bundles situated at a larger distance Ercm the central tube, and to maintain substantially the same length for each tube.
1'he helical flowing pattern of the cooling medium enables the ratio heat-e~changer surface/reactor volume to be varied over a large range. me tube di~neter mav be varied as well as the dis-tance between two layers of tubing in both the axial and the radial direc~ion. The diameter of the cooling tubes is suitably chosen between 4 and 55 mm, especially between 10 and 35 mm. The distance between two adjacent rings of tubes or tube bundles (distance in the radial direction) is suitably chosen between 10 and 50 mm, especially between 15 and 25 mm, and the distance between two adjacent coils ly~lg in a concentric ring tdistance in the axial direction) is suitably chosen between 10 and 200 mm, especially between 10 and 50 mm. The helical wound tube bundles make it possible to use hemispheric tube sheet designs, thus avoiding the less suitable flat tube sheets.
Heat transfer in the reaction zone(s) can be further i~proved by arranging screens of (e.g. wire mesh) around a group of heat exchange tubes, which are preferably arranged in at least one concentric ring around the collection tube, in order to keep the space between adiacent tubes free frcm catalyst particles; as a result tube spacing can be much closer than without the application of screens. Of course, the openings in said screens should be small enough to prevent catal~st particles or other particulate contact material present in the reaction zone(s) frsm passing through a screen.
In a~dition, or as alternative, to the afore-mentioned screens the heat exchange tubes can be provided with fins (e.g. extendi~ng radially, tangentially or spirally from their outer surface) in order to improve heat transfer from the reaction zone to the - cooling fluid.
As a result of improved heat transfer, in the present process the num~er of heat exchange tubes can be Xept relatively small, thus allowing a relatively large amount of catalyst to be pacXed in a given volume of the reaction zone(s).
.~
The heat exchange tubes are preferably spaced in such a m3nner in the reaction zone(s) that an optimal temperature profile for a particular reaction is attained therein in radial direction.
~oreover, each group (e.g. concentric ring) of heat exch~nge tubes is preferably in ccmmunication with separate ccDli~g 1uid in- and outlet means which can be operated independently of other groups of heat eYchange tubes in order to attain optimal control over the temperature profile in the reaction zone(s).
Water is usually used as cooling medium. Preferably the ~7ater evaporates at least partially in the tubes. This enables the hea~
of reaction to be removed from the reaction zone by producing steam. Other cooling media as organic compounds, for instance biphenyl thermal oils, or liquid metals may also be used.
me process according to the invention is particularly suitable lS for converting a synthesis gas feed (at least partly) into ~ydro-carbons, preferably having at least 10 carbon atoms per molecule;
most preferably paraffinic hydrocar~ons having at least 20 carbon atc~s per m~lecule are thus prepared.
The synthesis gas feed referred to hereinabcve contains as major ccmponents hydrogen and carbon monoxide; in addition said $eed may contain carbon dioxide, water, nitrogen, argon and minor amounts of ccmFounds having 1-4 carbon atoms per molecule such as methane, methanol or ethene.
e synthesis gas feed can be prepared in any manner known in the art e.g. by means of steam/axygen gasification of a hydrocar-bonaceous ~aterlal such as brown coal, anthracite, coke, crude mineral oil and fractions thereof, and oil recovered from tar sand and bituminous shale. Alternatively, steam methane reformong and/or catalytic partial oxidation of a hydrocarbonaceous material with an oxygen-containing gas can be applied to produce synthesis gas excellently suitable for use in the process according to ~he invention.
Ihe present process is preferably carried out at a temperature frcm 100-50~ C, a total pressure from 1-200 bar abs. and a space 35 velocity from 200-20,000 m3 (S.T.P.) gaseous feedJm3 reaction :
g6~ ~3 zone/hour. Particularly preferred process conditions for the preparation of hydrocarbons include a temperature fram 150-300 C, a pressure from 5-100 bar abs. and a space velocity from 500-5000 m3 (S.T.P.) gaseous feed/m3 reaction zone/hour. The expression "S.T.P." as re~erred to hereinbefore means Standard Temperature (of 0 C) and Pressure (1 bar abs.). In case synthesis gas is employed as gaseous feed, the H2/CO molar ratio therein is preferably from 0.4-4 and most preferably fram 0.8-2.5.
Suitable catalysts for the preparation of (paraffinic) hydro-carbons from synthesis gas contain at least a metal (compound) fromGroup 8 of the Periodic Table of the Elements, preferably a non-noble metal, in particular cobalt, optionally in cc~bination wlth a noble metal e.g. ruthenium, on a refractory oxide carr1er such as silica, alum~na or silica-alum1na, in particular silica. Furthermore, the catalysts preferably contain at least one other metal (ccmpoundj ~rom Group 4b and/or 6b, most preferably chosen frcm the group consisting of zirconium, titanium and chrcmium. The catalysts preferably contain fram 3-60 parts by weight of cobalt, opt1onally 0.05-0.5 parts by weight of ruthenium, and from 0.1-100 parts by weight of other metal(s) per 100 parts by we1ght of cærier.
The metals may be incorporated into the catalyst by means of any method kncwn therefor in the art, such as (gas)impregnation (e.g. in the form of chlorides or carbonyls), ion-exchange, kneading or precipitation. Kneading and impregnation are preferred methods, the latter in particular ~or the incorporation of cobalt. m e resulting catalyst composition is preferably calcined at temperatures frcm 3~0-700 C after each impregnation or kneading step.
The catalysts are preferably employed in the present process in the form of spherical, cylindrical or lobed particles with a diame~er from 0.1-15 mm, and in particular from 0.5-5 m~. The catalyst particles can be prepared by means of any method known in the art, such as pressing or extruding of pcwdry catalyst material, if desired together with a binder material. Catalyst spheres, in particular silica-containing spheres, are suitably prepared b~
means of the l'oil-drop" meth~d whereby said spheres are formed as -~ ~36~
drops of a silica gel which are solidified while falling in an oil bath.
The catalyst present in the reaction zone(s) may be kept in contact with liquid product in case relatively heavy paraffins (with more than 20 carbon atcms per molecule) are synthesized with the present process in order to avoid the formation of carbonaceous deposits on the catalysts. Liquid redistribution means (e.g. in the form of trays or layers of material having a relatively lcw permea-bility for liquid and/or gas) can be arranged mside the reaction zone(s) in order to promote substantially horizontal radial flcw patterns in the particulate catalyst mass and the desired optimal contact with liquid product. Furthermore, an oriented packing of non-spherical catalyst can be employed to promote radial flow in the reaction zone.
Furthermore, the invention relates to liquid products whenever prepared by a process as described hereinbefore.
In addition, the invention relates to an apparatus whenever used ~or carrying out the process as described hereinbefore which apparatus comprises a housing ha~ing gaseous feed inlet means and product outlet means and enclosing at least one reaction section which is in communication with the feed inlet means and via collec-tion means with the product outlet means, which collection means are arranged relative to the reaction section(s) such that a substantially radial flcw pattern can be maintained in said section(s).
The apparatus can furthermo~e contain catalyst supply- and removal means ccmmunicating with the reaction section(s). The product outlet means are suitably in communication with gas/liquid separation means a~r~nged in the botto~ section of the housing below the reaction section(s), which separation means are in communication with the collection means. The upper section of the housing (above the reacticn section(s)) is sui-tably provided with a steam drum which is in ccmmunication with the outlets of cooling tubes which are preerably arranged inside the reaction section(s) as discussed hereinbefore. The other previously discussed preferred :
~ .P ~J~36~.~ '3 features of the process according to the invention are also appli-cable to said apparatus.
A preferred embodiment of the apparatus according to the invention is shown schematically in Figures 1 and 2 in which reference numerals relating to corresponding parts are the same.
In Figure 1 a longitudinal section of the present apparatus as shown.
Figure 2 represents a cross section at AA of the apparatus as depicted in Figure 1.
The appæ atus as schematically shc~n in Figures 1 and 2 ccmprises a housing (1) having gaseous feed inlet means (2) (depicted as a ring-shaped manifold provided with a plurality of nozzles (3) for optimal feed distri~ution) and product outlet means (4~ connected to a perforated central collection tube (S) which is closed at its upper end (6). Reaction section (7) is laterally enclosed by a cylindrical wall section (8) provided with openings for the passage of gaseous feed therethrough. Reaction section (7) can be filled with catalyst via catalyst supply means (9) in the form of a frusto-conical section arranged in the upper section (10) of housing (1). The bottom section (11) of reaction section (7) is frusto-conically shaped for easy catalyst withdrawal and connected to tubular catalyst withdrawal means (12) which are prcvided with a (e~g. rotary) catalyst valve (13). Section (7) is furthermore provided with a plurality of heat exchange (cooling) tubes (14) 2S which are arranged in concentric rings, each ring of tubes being connected to separate inlet means (15, 16) and outlet means (17, 18) for optimal temperature regulation inside reaction section (7).
Heat exchange tubes (14) may have been manufactured fr~m straight tubes as indicated in the drawing. In a preferred embodiment these heat exchangers are in the form of a helical wound tube or tube bundle.
. ;
:~:
AT LE~ST PARTLY LIQUID PRODUCT
The invention relates to a process for converting a gaseous feed into an at least partly liquid product.
In known processes wherein (partly) liquid products are prepared at the conditions prevailing in the reaction zone, in most cases gravity flQw of the liquid products tcwards the bottom of said zone is employed to collect and remove said products.
A problem associated with such processes is that the pressure drGp over the reaction zo~e is usually relatively large, especially when the reaction zone is filled with particulate (catalyst) material, which makes it unattractive to apply relatively high space velocities in said zone~ Morecver, temperature control in case of exothermic reactions is sc~etimes difficult, unless special measures are taken to prevent this; one of such measures comprises carrying out the process in a plurality (sometimes even more than l000) of tubular reaction zones.
Surprisingly, it has now been fsund that the afore-mentioned problems can be overccme by applying a radial flow regime inside the preferably substantially cylindrical xeaction zone of a normally substantially vertically extending reactor, ~ notwithstanding the presence of liquid product therein, and remc~ing liquid- and gaseous product (including unconverted gaseous feed) toge*her frc~ the reaction zone.
The invention therefore relates to a process for converting a gaseous feed into an at least partly liquid product which ccmprises ; 25 ~ introducing the;gaseous feed into at least one reaGtion zone which is nadntained at conversion conditions, allowing said feed to flow substantially radially towards a product collection zone, and removing liquid- and gaseous product tcgether frcm the reaction Qne through the collection zone.
Processes~and apparatuses in which a radial flow is maintained in the reaction zone are known fQr gas phase reactions such as the : ~ , preparation of methanol or low-boiling hydrocarbons from synthesis gas.
A major advantage of the process according to the invention is that the temperature inside the reaction zone can be optimally controlled by passing the gaseous feed with a relatively high velocity through said æone, which now becomes attractive because the pressure drop over the reaction zone is relatively ~ow. Conse-quently, recycling of liquid produ~t thro~1gh the reaction zone(s3 as sometimes applied in order to maintain te~perature stability therein, in particular when the process is highly exothermic, is not necessary.
Furthermore, it now becomes feasible to operate a process in which liquid product is formed in stacked reaction zones without incurring excessive pressure drop over the zones, due to the fact that the length of the flcw paths through the reaction zones remains substantially equal independent of the number of said zones.
Preferably, the process according to the invention is carried out in such a r~anner that the gaseous feed flows inwardly tcwards the product collection zone arranged substantially centrally inside tha reaction zone(s); this set-up is preferred because the volume of gas flowing towards the collective zone diminishes with the gradual formation of li~uid products resulting in a decrease in space velocity, which decrease is at least partly compensated by the decreasing area through which the gas flows tcwards the central collection zone.
Alternatively, the process according to the invention is carried out with radial outward flow of gaseous feed i~troduced into the reaction zone(s) via feed inlet means arranged centrally in said zone(s~, employing e.g. an annular collection zone which laterally surrounds the reaction zone(s). It is also poss~ble to apply at least one reaction zone with inward flcw in ccmbination with at least one reaction zone with outward flcw.
The radial flow velocity of the ccmbined gaseous feed and -product stream is preferably maintained at a value sufficient to 3~ 3 allow at least a major part (i.e. more than 50% by weight, and most preferably substantially all) of the liquid product to be removed frcm the reaction zone(s) by said stream ln order to avoid non-radial flcw therein.
The present process is particularly suited for catalytic (especially exothermic) conversions, in which case the reaction zone(s) contain(s) at least one catalyst bed. It is also possible to carry out the process in a plurality of stacked catalyst beds which may contain the same or different catalysts. Moreover, each catalyst bed may contain at least two (e.g. annular) zones comprising the same or diferent catalysts.
Heat produced in the catalyst bed(s) can be rem~ved in some cases simply by mainta~ning in the reaction zone(s) an adequate space velocity of the gaseous feed. ~cwever, in many cases it will lS be highly desirable to incorporate at least one heat exchange zone in the reaction zone(s), preferably in the form of heat exchange tubes through which a cooling fluid (e.g. water and/or steam) is led.
The radial flow pattern in the reaction zone(s) results in excellent heat transfer to the heat exchange zones e~en at relative-ly low gas velocities, in particular when heat exchange tubes are arranged in the reaction zone(s) substantially parallel to a central, preferably perforated, collection tube, more particular when the heat exchange zones are arranged in concentric rings.
It is particularly preferred to use one or more heat exchange means situated in a concentric ring or a numb.er of concentric rings around the central supply or collection tube in the form of helical wound tubes or tube bundles, each tube bundle comprising two or more helical wound tubes of substantially the same dimensions.
mus, the cooling medium flows via one or more helical patternssituated concentrically æound the central supply or collection tube, each pattern containing one or more helixes. When two or more concentrical tubes or tube bundles are used, the screw-direction of the helixes of two adjacent tubes or tube bundles is preferably opposite to each other. When two or more tu`be bundles are used it is preferred to use an increasing number of helical wound tubes in 1~361 2,3 bundles situated at a larger distance Ercm the central tube, and to maintain substantially the same length for each tube.
1'he helical flowing pattern of the cooling medium enables the ratio heat-e~changer surface/reactor volume to be varied over a large range. me tube di~neter mav be varied as well as the dis-tance between two layers of tubing in both the axial and the radial direc~ion. The diameter of the cooling tubes is suitably chosen between 4 and 55 mm, especially between 10 and 35 mm. The distance between two adjacent rings of tubes or tube bundles (distance in the radial direction) is suitably chosen between 10 and 50 mm, especially between 15 and 25 mm, and the distance between two adjacent coils ly~lg in a concentric ring tdistance in the axial direction) is suitably chosen between 10 and 200 mm, especially between 10 and 50 mm. The helical wound tube bundles make it possible to use hemispheric tube sheet designs, thus avoiding the less suitable flat tube sheets.
Heat transfer in the reaction zone(s) can be further i~proved by arranging screens of (e.g. wire mesh) around a group of heat exchange tubes, which are preferably arranged in at least one concentric ring around the collection tube, in order to keep the space between adiacent tubes free frcm catalyst particles; as a result tube spacing can be much closer than without the application of screens. Of course, the openings in said screens should be small enough to prevent catal~st particles or other particulate contact material present in the reaction zone(s) frsm passing through a screen.
In a~dition, or as alternative, to the afore-mentioned screens the heat exchange tubes can be provided with fins (e.g. extendi~ng radially, tangentially or spirally from their outer surface) in order to improve heat transfer from the reaction zone to the - cooling fluid.
As a result of improved heat transfer, in the present process the num~er of heat exchange tubes can be Xept relatively small, thus allowing a relatively large amount of catalyst to be pacXed in a given volume of the reaction zone(s).
.~
The heat exchange tubes are preferably spaced in such a m3nner in the reaction zone(s) that an optimal temperature profile for a particular reaction is attained therein in radial direction.
~oreover, each group (e.g. concentric ring) of heat exch~nge tubes is preferably in ccmmunication with separate ccDli~g 1uid in- and outlet means which can be operated independently of other groups of heat eYchange tubes in order to attain optimal control over the temperature profile in the reaction zone(s).
Water is usually used as cooling medium. Preferably the ~7ater evaporates at least partially in the tubes. This enables the hea~
of reaction to be removed from the reaction zone by producing steam. Other cooling media as organic compounds, for instance biphenyl thermal oils, or liquid metals may also be used.
me process according to the invention is particularly suitable lS for converting a synthesis gas feed (at least partly) into ~ydro-carbons, preferably having at least 10 carbon atoms per molecule;
most preferably paraffinic hydrocar~ons having at least 20 carbon atc~s per m~lecule are thus prepared.
The synthesis gas feed referred to hereinabcve contains as major ccmponents hydrogen and carbon monoxide; in addition said $eed may contain carbon dioxide, water, nitrogen, argon and minor amounts of ccmFounds having 1-4 carbon atoms per molecule such as methane, methanol or ethene.
e synthesis gas feed can be prepared in any manner known in the art e.g. by means of steam/axygen gasification of a hydrocar-bonaceous ~aterlal such as brown coal, anthracite, coke, crude mineral oil and fractions thereof, and oil recovered from tar sand and bituminous shale. Alternatively, steam methane reformong and/or catalytic partial oxidation of a hydrocarbonaceous material with an oxygen-containing gas can be applied to produce synthesis gas excellently suitable for use in the process according to ~he invention.
Ihe present process is preferably carried out at a temperature frcm 100-50~ C, a total pressure from 1-200 bar abs. and a space 35 velocity from 200-20,000 m3 (S.T.P.) gaseous feedJm3 reaction :
g6~ ~3 zone/hour. Particularly preferred process conditions for the preparation of hydrocarbons include a temperature fram 150-300 C, a pressure from 5-100 bar abs. and a space velocity from 500-5000 m3 (S.T.P.) gaseous feed/m3 reaction zone/hour. The expression "S.T.P." as re~erred to hereinbefore means Standard Temperature (of 0 C) and Pressure (1 bar abs.). In case synthesis gas is employed as gaseous feed, the H2/CO molar ratio therein is preferably from 0.4-4 and most preferably fram 0.8-2.5.
Suitable catalysts for the preparation of (paraffinic) hydro-carbons from synthesis gas contain at least a metal (compound) fromGroup 8 of the Periodic Table of the Elements, preferably a non-noble metal, in particular cobalt, optionally in cc~bination wlth a noble metal e.g. ruthenium, on a refractory oxide carr1er such as silica, alum~na or silica-alum1na, in particular silica. Furthermore, the catalysts preferably contain at least one other metal (ccmpoundj ~rom Group 4b and/or 6b, most preferably chosen frcm the group consisting of zirconium, titanium and chrcmium. The catalysts preferably contain fram 3-60 parts by weight of cobalt, opt1onally 0.05-0.5 parts by weight of ruthenium, and from 0.1-100 parts by weight of other metal(s) per 100 parts by we1ght of cærier.
The metals may be incorporated into the catalyst by means of any method kncwn therefor in the art, such as (gas)impregnation (e.g. in the form of chlorides or carbonyls), ion-exchange, kneading or precipitation. Kneading and impregnation are preferred methods, the latter in particular ~or the incorporation of cobalt. m e resulting catalyst composition is preferably calcined at temperatures frcm 3~0-700 C after each impregnation or kneading step.
The catalysts are preferably employed in the present process in the form of spherical, cylindrical or lobed particles with a diame~er from 0.1-15 mm, and in particular from 0.5-5 m~. The catalyst particles can be prepared by means of any method known in the art, such as pressing or extruding of pcwdry catalyst material, if desired together with a binder material. Catalyst spheres, in particular silica-containing spheres, are suitably prepared b~
means of the l'oil-drop" meth~d whereby said spheres are formed as -~ ~36~
drops of a silica gel which are solidified while falling in an oil bath.
The catalyst present in the reaction zone(s) may be kept in contact with liquid product in case relatively heavy paraffins (with more than 20 carbon atcms per molecule) are synthesized with the present process in order to avoid the formation of carbonaceous deposits on the catalysts. Liquid redistribution means (e.g. in the form of trays or layers of material having a relatively lcw permea-bility for liquid and/or gas) can be arranged mside the reaction zone(s) in order to promote substantially horizontal radial flcw patterns in the particulate catalyst mass and the desired optimal contact with liquid product. Furthermore, an oriented packing of non-spherical catalyst can be employed to promote radial flow in the reaction zone.
Furthermore, the invention relates to liquid products whenever prepared by a process as described hereinbefore.
In addition, the invention relates to an apparatus whenever used ~or carrying out the process as described hereinbefore which apparatus comprises a housing ha~ing gaseous feed inlet means and product outlet means and enclosing at least one reaction section which is in communication with the feed inlet means and via collec-tion means with the product outlet means, which collection means are arranged relative to the reaction section(s) such that a substantially radial flcw pattern can be maintained in said section(s).
The apparatus can furthermo~e contain catalyst supply- and removal means ccmmunicating with the reaction section(s). The product outlet means are suitably in communication with gas/liquid separation means a~r~nged in the botto~ section of the housing below the reaction section(s), which separation means are in communication with the collection means. The upper section of the housing (above the reacticn section(s)) is sui-tably provided with a steam drum which is in ccmmunication with the outlets of cooling tubes which are preerably arranged inside the reaction section(s) as discussed hereinbefore. The other previously discussed preferred :
~ .P ~J~36~.~ '3 features of the process according to the invention are also appli-cable to said apparatus.
A preferred embodiment of the apparatus according to the invention is shown schematically in Figures 1 and 2 in which reference numerals relating to corresponding parts are the same.
In Figure 1 a longitudinal section of the present apparatus as shown.
Figure 2 represents a cross section at AA of the apparatus as depicted in Figure 1.
The appæ atus as schematically shc~n in Figures 1 and 2 ccmprises a housing (1) having gaseous feed inlet means (2) (depicted as a ring-shaped manifold provided with a plurality of nozzles (3) for optimal feed distri~ution) and product outlet means (4~ connected to a perforated central collection tube (S) which is closed at its upper end (6). Reaction section (7) is laterally enclosed by a cylindrical wall section (8) provided with openings for the passage of gaseous feed therethrough. Reaction section (7) can be filled with catalyst via catalyst supply means (9) in the form of a frusto-conical section arranged in the upper section (10) of housing (1). The bottom section (11) of reaction section (7) is frusto-conically shaped for easy catalyst withdrawal and connected to tubular catalyst withdrawal means (12) which are prcvided with a (e~g. rotary) catalyst valve (13). Section (7) is furthermore provided with a plurality of heat exchange (cooling) tubes (14) 2S which are arranged in concentric rings, each ring of tubes being connected to separate inlet means (15, 16) and outlet means (17, 18) for optimal temperature regulation inside reaction section (7).
Heat exchange tubes (14) may have been manufactured fr~m straight tubes as indicated in the drawing. In a preferred embodiment these heat exchangers are in the form of a helical wound tube or tube bundle.
. ;
:~:
Claims (15)
1. Process for converting a gaseous feed into an at least partly liquid product which comprises introducing the gaseous feed into at least one reaction zone which is maintained at con-version conditions, allowing said feed to flow substantially radial-ly towards a product collection zone, and removing liquid- and gaseous product together from the reaction zone through the collection zone.
2. Process according to claim 1 wherein the gaseous feed flows inwardly towards the product collection zone arranged substantially centrally inside the reaction zone(s).
3. Process according to claim 1 or 2 wherein the reaction zone(s) contain(s) at least one catalyst bed.
4. Process according to claim 1, wherein the reaction zone(s) contain(s) a heat exchange zone.
5. Process according to claim 4, wherein heat is removed from the reaction zone by a cooling medium which flows via one or more helical patterns situated concentrically around the central supply or collection tube, each pattern containing one or more helixes.
6. Process according to claim 5, wherein the cooling medium flows via two or more concentrical helical patterns wherein the screw-directions of adjacent helical patterns are opposite to each other.
7. Process according to claim 5 or 6, wherein the cooling medium flows via two or more concentrical helical patterns wherein an increasing number of helixes is used in the helical patterns which are situated at a larger distance from the central tube, and which helixes have substantially the same length.
8. Process according to claim 1 or 2 wherein the radial flow velocity of the combined gaseous feed and -product stream is maintained at a value sufficient to allow at least a major part of the liquid product to be removed from the reaction zone(s) by said stream.
9. Process according to claim 1 or 2 wherein a synthesis gas feed is converted into hydrocarbons, preferably having at least
10 carbon atoms per molecule.
10. Process according to claim 1 or 2 which is carried out at a temperature from 100-500°C, a total pressure from 1-200 bar abs. and a space velocity from 200-20,000 m3 (S.T.P.) gaseous feed/m3 reaction zone/hour.
10. Process according to claim 1 or 2 which is carried out at a temperature from 100-500°C, a total pressure from 1-200 bar abs. and a space velocity from 200-20,000 m3 (S.T.P.) gaseous feed/m3 reaction zone/hour.
11. Liquid products whenever prepared by a process according to claim 1 or 2.
12. Apparatus whenever used for carrying out the process according to claim 1 which comprises a housing having gaseous feed inlet means and product outlet means and enclosing at least one reaction section which is in communication with the feed inlet means and via collection means with the product outlet means, which collection means are arranged relative to the reaction section(s) such that a substantially radial flow pattern can be maintained in said section(s).
13. Apparatus according to claim 12, wherein the reaction section(s) contain(s) one or more heat exchange means situated in a concentric ring or a number of concentric rings around a central supply or collection tube in the form of helical wound tubes or tube bundles, each tube bundle comprising two or more helical wound tubes of substantially the same dimensions.
14. Apparatus according to claim 13, comprising two or more concentrical tubes or tube bundles wherein the screw-direction of the helixes of two adjacent tubes or tube bundles is opposite to each other.
15. Apparatus according to claim 13 or 14, comprising two or more concentrical tube bundles wherein an increasing number of helical wound tubes is used in bundles situated at a larger dis-tance from the central tube.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8618110 | 1986-07-24 | ||
| GB868618110A GB8618110D0 (en) | 1986-07-24 | 1986-07-24 | Converting gaseous feed into liquid product |
| GB8713483 | 1987-06-09 | ||
| GB878713483A GB8713483D0 (en) | 1987-06-09 | 1987-06-09 | Converting gaseous feed into liquid product |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1296023C true CA1296023C (en) | 1992-02-18 |
Family
ID=26291085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000542731A Expired - Fee Related CA1296023C (en) | 1986-07-24 | 1987-07-22 | Process for converting a gaseous feed into an at least partly liquidproduct |
Country Status (7)
| Country | Link |
|---|---|
| AU (1) | AU589287B2 (en) |
| CA (1) | CA1296023C (en) |
| GB (1) | GB2193444B (en) |
| MY (1) | MY102345A (en) |
| NO (1) | NO177665C (en) |
| NZ (1) | NZ221159A (en) |
| SG (1) | SG4091G (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9301723D0 (en) * | 1993-01-28 | 1993-03-17 | Norske Stats Oljeselskap | Solid/liquid treatment apparatus and catalytic multi-phase reactor |
| GB2281224B (en) * | 1993-08-24 | 1998-02-11 | Norske Stats Oljeselskap | Solid/liquid slurry treatment apparatus and catalytic multi-phase reactor |
| US6864293B2 (en) | 2001-12-20 | 2005-03-08 | Sasol Technology (Proprietary) Limited | Production of liquid and, optionally, gaseous products from gaseous reactants |
| US8888872B2 (en) | 2010-07-06 | 2014-11-18 | General Electric Company | Gasifier cooling system |
| EP2933016A1 (en) * | 2014-04-18 | 2015-10-21 | Casale Sa | Isothermal tubular catalytic reactor |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4033727A (en) * | 1976-07-06 | 1977-07-05 | Phillips Petroleum Company | Separator ring in fixed bed radial flow catalytic reactor |
| JPS5839572B2 (en) * | 1979-04-03 | 1983-08-31 | 東洋エンジニアリング株式会社 | Reactor and its use |
| US4341737A (en) * | 1979-05-22 | 1982-07-27 | The Lummus Company | Apparatus for carrying out catalytic exothermic and endothermic high-pressure gas reactions |
| CH666198A5 (en) * | 1985-09-13 | 1988-07-15 | Ammonia Casale Sa | REACTOR FOR CATALYTIC SYNTHESIS OF AMMONIA, METHANOL AND HIGHER ALCOHOLS. |
-
1987
- 1987-07-22 GB GB8717271A patent/GB2193444B/en not_active Expired - Fee Related
- 1987-07-22 MY MYPI87001081A patent/MY102345A/en unknown
- 1987-07-22 NZ NZ221159A patent/NZ221159A/en unknown
- 1987-07-22 AU AU76001/87A patent/AU589287B2/en not_active Ceased
- 1987-07-22 CA CA000542731A patent/CA1296023C/en not_active Expired - Fee Related
- 1987-07-23 NO NO873092A patent/NO177665C/en not_active IP Right Cessation
-
1991
- 1991-01-28 SG SG40/91A patent/SG4091G/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| AU589287B2 (en) | 1989-10-05 |
| MY102345A (en) | 1992-06-17 |
| GB2193444B (en) | 1990-10-31 |
| NO177665B (en) | 1995-07-24 |
| SG4091G (en) | 1991-04-05 |
| NO873092D0 (en) | 1987-07-23 |
| NZ221159A (en) | 1989-01-27 |
| NO177665C (en) | 1995-11-01 |
| GB2193444A (en) | 1988-02-10 |
| AU7600187A (en) | 1988-01-28 |
| NO873092L (en) | 1988-01-25 |
| GB8717271D0 (en) | 1987-08-26 |
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