WO1992008771A1 - Procede d'hydrodesulfuration - Google Patents

Procede d'hydrodesulfuration Download PDF

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Publication number
WO1992008771A1
WO1992008771A1 PCT/GB1990/001705 GB9001705W WO9208771A1 WO 1992008771 A1 WO1992008771 A1 WO 1992008771A1 GB 9001705 W GB9001705 W GB 9001705W WO 9208771 A1 WO9208771 A1 WO 9208771A1
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WO
WIPO (PCT)
Prior art keywords
tray
liquid
hydrodesulphurisation
catalyst
reaction
Prior art date
Application number
PCT/GB1990/001705
Other languages
English (en)
Inventor
George Edwin Harrison
Donald Hugh Mckinley
Alan James Dennis
Original Assignee
Davy Mckee (London) Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from GB898910712A external-priority patent/GB8910712D0/en
Application filed by Davy Mckee (London) Limited filed Critical Davy Mckee (London) Limited
Priority to RU9093005231A priority Critical patent/RU2066339C1/ru
Priority to AU66364/90A priority patent/AU658130B2/en
Priority to PCT/GB1990/001705 priority patent/WO1992008771A1/fr
Priority to KR1019930701364A priority patent/KR930702471A/ko
Publication of WO1992008771A1 publication Critical patent/WO1992008771A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
    • C10G65/02—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only
    • C10G65/04—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including only refining steps
    • 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
    • B01J8/20—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with liquid as a fluidising medium
    • B01J8/22—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles with liquid as a fluidising medium gas being introduced into the liquid
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/02—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing
    • C10G45/14—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing with moving solid particles
    • C10G45/16—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing with moving solid particles suspended in the oil, e.g. slurries
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
    • C10G2400/14—White oil, eating oil

Definitions

  • This invention relates to a process for hydrodesulphurisation of a hydrocarbon feedstock.
  • sulphur in varying amounts, depending upon the source of the crude oil and any subsequent treatment that it may have undergone.
  • numerous sulphur compounds have been identified in crude oil including hydrogen sulphide (H 2 S), C 1 to C 5 primary alkyl mercaptans, C 3 to C 8 secondary alkyl mercaptans, C 4 to C 6 tertiary alkyl mercaptans, cyclic mercaptans (such as cyclopentane thiol, cyclohexane thiol and cis-2-methylcyclopentane thiol), open chain sulphides of the formula R-S-R' where R and R' represent C 1 to C 4 alkyl groups, mono-, bi- and tri-cyclic sulphides, thiophene, alkyl substituted thiophenes, condensed thiophenes (such as benzo(b)thiophene, isothi
  • low API gravity crude oils usually contain more sulphur than high API gravity crude oils, although there are some exceptions.
  • distribution of sulphur compounds in the different fractions of petroleum varies mainly with the boiling range of the fractions.
  • lighter fractions such as naphtha contain fewer sulphur compounds, whilst the content of sulphur compounds also increases as the boiling point or API density or molecular weight of the fraction increases.
  • hydrodesulphurisation In such a process the hydrocarbon fraction is admixed with hydrogen and passed over a
  • hydrodesulphurisation catalyst under appropriate temperature and pressure conditions.
  • the aim is to rupture the carbon-sulphur bonds present in the feedstock and to saturate with hydrogen the resulting free valencies or olefinic double bonds formed in such a cleavage step.
  • the aim is to convert as much as possible of the organic sulphur content to hydrocarbons and to H 2 S.
  • cyclic sulphur-containing compounds are harder to hydrogenate than the open chain compounds and, within the class of cyclic sulphur-containing compounds, the greater the number of rings that are present the greater is the difficulty in cleaving the carbon-sulphur bonds.
  • combustion gases typically include aromatic hydrocarbons, which may be present because of incomplete combustion, and carbonaceous particulate matter often containing polycyclic aromatic hydrocarbons, metal compounds, oxygenated organic materials, and other potentially toxic materials.
  • hydrotreating is often used as a more general term to embrace not only the hydrodesulphurisation reactions but also the other reactions that occur, including
  • hydrotreating is further explained in an article "Here is a nomenclature-system proposed for hydroprocessing", The Oil and Gas Journal, October 7, 1968, pages 174 to 175.
  • HDS hydrodesulphurisation
  • HDN hydrodenitrogenation
  • HDO hydrodeoxygenation
  • HDM hydrodemetallation
  • hydrotreating reactions are molybdenum disulphide, tungsten sulphide, sulphided nickel-molybdate catalysts (NiMoS x ), and cobalt-molybdenum alumina sulphide (Co-Mo/alumina).
  • the recycle hydrogen is passed through an H 2 S scrubber.
  • H 2 S scrubber In the "HYVAHL Process" a once-through operation for the liquid feed is also used. Again, amine scrubbing is used to remove H 2 S from the recycle hydrogen.
  • the Unionfining Process also utilises a once-through basis for the liquid feed. Co-current hydrogen and liquid flow is envisaged. Unreacted hydrogen is recycled.
  • gas recycle means that inert gases tend to accumulate in the circulating gas which in turn means that, in order to maintain the desired
  • the overall operating pressure must be raised to accommodate the circulating inert gases and that the size and cost of the gas recycle compressor must be increased and increased operating costs must be tolerated.
  • Figure 1 of this article illustrates a reactor with four catalyst beds with introduction of a mixture of hot gas and gas oil at the inlet end of the first bed and use of cold shots of gas oil between subsequent beds.
  • the catalyst activity is lowest at the exit end from the bed which is where the highest activity is really needed if the least tractable polycyclic organic sulphurous compounds are to undergo hydrodesulphurisation.
  • the catalysts used for hydrodesulphurisation are usually also capable of effecting hydrogenation of aromatic compounds, provided that the sulphur level is low.
  • the conditions required for carrying out hydrogenation of aromatic compounds are usually also capable of effecting hydrogenation of aromatic compounds, provided that the sulphur level is low.
  • aromatic compounds are generally similar to those required for hydrodesulphurisation. However, as the reaction is an equilibrium that is not favoured by use of high
  • Removal of H 2 S from a hydrodesulphurisation plant with a gas recycle system is normally effected by scrubbing the recycle gas with an amine.
  • the scrubber section has to be sufficiently large to cope with the highest levels of sulphurous impurities likely to be present in the feedstocks to be treated, the scrubber equipment has to be designed with an appropriate capacity, even though the plant will often be operated with low sulphur feedstocks. The capital cost of such scrubber equipment is significant.
  • the invention accordingly seeks to provide a process in which hydrodesulphurisation can be conducted more efficiently than in a conventional hydrodesulphurisation process. It also seeks to provide a hydrodesulphurisation process in which the activity of the catalyst is controlled favourably throughout the reactor to enable improved levels of hydrodesulphurisation of the feedstock to be achieved. It further seeks to provide a hydrodesulphurisation process which enables also a significant reduction in the aromatics content of the feedstock to be effected simultaneously with hydrodesulphurisation.
  • each tray defining a respective reaction stage adapted to hold a predetermined liquid volume and a charge of a sulphided solid
  • liquid downcomer means associated with each reaction tray adapted to allow liquid to pass down the column reactor from that tray but to retain solid catalyst thereon, and gas upcomer means
  • each reaction tray adapted to allow gas to enter that tray from below and to agitate the mixture of liquid and catalyst on that tray;
  • the gas entering the uppermost tray contains sufficient H 2 S and/or the liquid feedstock contains sufficient sulphur-containing material selected from H 2 S and active sulphur-containing materials to maintain the catalyst charge thereon in sulphided form.
  • active sulphur-containing materials there is meant materials which very rapidly form H 2 S under hydrodesulphurisation conditions in the presence of a hydrodesulphurisation catalyst.
  • examples of such materials include, for example, CS 2 , COS, alkyl mercaptans, dialkyl sulphides, and dialkyl disulphides.
  • the solid sulphided catalyst used in the process of the present invention is preferably selected from
  • molybdenum disulphide molybdenum disulphide, tungsten sulphide, cobalt sulphide, nickel/tungsten sulphide, cobalt/tungsten sulphide,
  • NiMoS x nickel-molybdate catalysts
  • CoO-MoO 3 /gamma-Al 2 O 3 catalyst sulphided nickel-molybdate catalysts
  • Typical hydrodesulphurisation conditions include use of a pressure in the range of from about 20 bar to about 150 bar and of a temperature in the range of from about 240°C to about 400°C.
  • Preferred conditions include use of a pressure of from about 25 bar to about 100 bar and of a temperature of from about 250°C to about 370°C.
  • the liquid sulphur-containing hydrocarbon feedstock may comprise a mixture of saturated hydrocarbons, such as n-paraffins, iso-paraffins, and naphthenes, in varying proportions. It may further comprise one or more aromatic hydrocarbons in amounts of, for example, from about 1 volume % up to about 30 volume % or more. If the
  • feedstock has a low content of aromatic hydrocarbons, then hydrodesulphurisation will be the predominant reaction occurring. However, if the feedstock has an appreciable content of aromatic hydrocarbons, then at least some
  • the stoichiometric hydrogen demand may thus be a function not only of the sulphur content of the feedstock but also of the aromatics content thereof.
  • the actual hydrogen consumption will be a function of the severity of the reaction conditions chosen, that is to say the operating temperature and pressure chosen.
  • the operating temperature and pressure chosen.
  • a high operating pressure a high operating temperature, or a combination of both.
  • concentration achievable does not depend solely upon the nature of the feedstock but also upon the severity of the reaction conditions used.
  • the reaction conditions used in the process of the invention will typically be chosen to reduce the residual sulphur content to about 0.5 wt % S or less, e.g. about 0.3 wt % S or less, even down to about
  • the process conditions will be selected with a view to reducing the sulphur content to very low levels and the aromatics content as far as possible.
  • the aim will be to reduce the aromatics content sufficiently, to provide a white oil which is a colourless, essentially non aromatic, mixture of paraffin and naphthenic oils which conform to the following specification:
  • the aim is to produce a product with a maximum uv absorption per centimetre at 260-350nm of 0.1, measured on a
  • feedstock must be hydrogenated.
  • the rate of supply of hydrogen-containing gas typically corresponds to an
  • H 2 feedstock molar feed ratio of from about 2:1 to about 20:1; preferably this ratio is from about 3:1 to about 7:1.
  • the hydrogen-containing gas may be obtained in known manner, for example by steam reforming or partial oxidation of a hydrocarbon feedstock, such as natural gas, followed by conventional steps such as the water gas shift reaction, CO 2 removal, and pressure swing adsorption.
  • the temperature on the uppermost reaction tray, which forms a first hydrodesulphurisation zone may be lower than on the next lower tray, which in turn may be lower than the
  • the temperature may be increased from tray to tray from the uppermost tray to an intermediate lower tray, but then the temperature is reduced from tray to tray on the succeeding lower trays.
  • the temperature increases tray by tray from the uppermost tray to the intermediate tray, but then decreases from tray to tray as the liquid passes down through the column reactor.
  • the feedstock will encounter progressively hotter conditions under essentially the same pressure, and progressively lower H 2 S partial pressures in passing down through successive reaction trays. Since the H 2 S partial pressure is lower on the second tray and on the lower trays than on the uppermost tray, the catalyst is effectively less sulphided and hence more active on the lower trays than on the uppermost tray. In this way the efficiency of
  • hydrodesulphurisation is enhanced, since the conditions on the lower trays are more favourable for reaction of the remaining sulphur-containing compounds, which will tend to be the least reactive compounds, such as polycyclic
  • the hydrogen-containing gas flowing to the uppermost tray comes from the next lower tray it will normally contain a proportion of H 2 S. Since the make-up gas is supplied below the lowermost tray, the concentration of H 2 S in the gas is at its highest in the gas feed to the uppermost tray. The level of organic sulphur-containing compounds is lowest in the liquid feed to the lowermost tray, but these compounds are the least reactive. Whilst a sufficient H 2 S partial pressure should be maintained on the lowermost tray in order to keep the catalyst on that tray in a sufficiently sulphided form to obviate the danger of hydrocracking on that tray, the catalyst activity will tend to be highest on this tray so that the conditions on this tray are favourable not only for effecting
  • hydrocarbon content of the feedstock can be effected, while at the same time achieving efficient removal of the less readily removed sulphur-containing materials, such as cyclic and polycyclic organic sulphur compounds.
  • catalysts can be used on different trays in the process of the invention.
  • a catalyst favouring hydrodesulphurisation, rather than hydrogenation of aromatic compounds can be used on the uppermost tray or on the uppermost few trays, whilst a catalyst that has greater activity for hydrogenation of aromatic compounds is used on the lower trays.
  • Means may be provided for withdrawing a mixture of catalyst and liquid from one or more trays. By providing suitable valves and pumps the same withdrawal means can also be used to charge fresh catalyst to each tray, either in order to vary the quantity of catalyst in response to changes in feedstock or operating conditions or in order to replenish the catalyst charge.
  • the sulphur contents of the gas and liquid feeds to the uppermost tray are monitored to ensure that there is sufficient H 2 S present to maintain the catalyst in sulphided form. More often than not the
  • feedstock will contain sufficient active sulphur-containing material or the hydrogen-containing gas fed thereto will contain sufficient H 2 S, or both, to maintain the catalyst in sufficiently sulphided form.
  • H 2 S or active sulphur-containing material on the uppermost tray, then a sufficient additional amount of H 2 S or of an active sulphur compound, such as CS 2 , COS, an alkyl mercaptan, a dialkyl sulphide, or a dialkyl disulphide, is added to the feedstock supplied to the uppermost tray to restore a safe level of sulphur on that tray.
  • a sulphur concentration in the form of H 2 S or of an active sulphur material, of from about 1 ppm, and preferably at least about 5 ppm up to about 1000 ppm.
  • the sulphur concentration may range from about 10 ppm upwards, e.g. from about 40 ppm up to about 100 ppm.
  • sulphur concentration on at least one lower tray, for example the lowermost tray, and possibly on each lower tray below the uppermost tray, and to bleed into the feed to that tray, if necessary, sufficient H 2 S or sufficient additional active sulphur-containing material, such as CS 2 , COS, or an alkyl mercaptan, a dialkyl sulphide, or a dialkyl disulphide, to maintain the sulphur concentration within the range of from about 1 ppm to about 1000 ppm, for example from about 5 ppm to about 100 ppm.
  • the liquid hydrocarbon feedstock may be, for example, selected from naphthas, kerosenes, middle
  • distillates vacuum gas oils, lube oil brightstocks, diesel fuels, atmospheric gas oils, light cycle oils, light fuel oils, and the like.
  • the reaction trays include a floor which slopes at an angle equal to or greater than the angle of repose of the catalyst particles under the liquid.
  • the reaction trays may each have a floor of frusto-conical shape whose slope is equal to or greater than the angle of repose of the catalyst particles under the liquid present on the tray.
  • the reaction trays may each have a floor and a surrounding wall, the floor including an inner floor portion which slopes
  • reaction tray may comprise one or more bubble caps of conventional design.
  • bubble caps of conventional design.
  • each such bubble cap is associated with a relatively tall riser tube, the height of which is
  • This relatively tall riser tube is covered by a corresponding inverted, relatively tall bubble cap.
  • a non-return valve may also be fitted in such a riser tube. If in the course of a single passage through the column reactor the desired degree of desulphurisation or dearomatisation is not achieved, then the treated material can be re-treated in a subsequent column reactor or other form of hydrodesulphurisation reactor, possibly under more severe conditions.
  • Figure 1 is a flow diagram of a
  • hydrodesulphurisation plant designed to operate using the process of the present invention
  • Figure 2 is a vertical section through a tray of the column reactor of the hydrodesulphurisation plant of Figure 1;
  • Figure 3 is a similar vertical section through a tray of a modified design of column reactor
  • Figure 4 is a flow diagram of an experimental apparatus
  • Figure 5 is a diagram of a reaction tray of the apparatus of Figure 4.
  • Figure 6 is a diagram showing the relationship between the aromatics content of the product and temperature of operation.
  • a hydrodesulphurisation plant includes a column reactor vessel 1 provided with a plurality of reaction trays 2 each holding a charge of a particulate sulphided hydrodesulphurisation catalyst and a predetermined volume of liquid.
  • a hydrogen-containing gas is admitted to the reactor vessel 1 in line 3.
  • Spargers 4 mounted in each tray 2 permit upward flow of gas through the liquid on each tray 2.
  • a sulphur-containing hydrocarbon feedstock to be treated is supplied to the plant in line 5 and is admixed with recycled liquid in line 6 to form a mixed feed in line 7 which feeds the topmost tray 2 of reactor vessel 1.
  • Downcomers 8 allow liquid to pass
  • Each tray 2 is provided with a corresponding heat exchanger coil 10.
  • a temperature controller 11 is provided for each tray 2 and controls the action of a corresponding control valve 12, which controls the flow to the respective heat exchange coil 10 of a heat exchange medium supplied in line 13 to an inlet manifold 14.
  • Reference numeral 15 indicates the return flow manifold, and reference numeral 16 the return flow line for the heat exchange medium. This arrangement enables the temperature on each tray 2 to be individually controlled.
  • Off-gas is recovered from the top of column reactor vessel 1 in line 17. This contains vapours of the liquid feedstock, gaseous products of the
  • hydrodesulphurisation reaction including H 2 S, and inert gases contained in the feed gas in line 3.
  • Condensate is withdrawn from separator 20 by way of lines 22 and 23 by pump 24 and is recirculated to
  • separator 20 in lines 25 and 26 through flow constrictor 27 which thus creates a pressure in lines 25 and 26 that is greater than that in separator 20.
  • Part of the liquid flowing in line 25 is returned to column reactor 1 by way of lines 28, 29 and 6 under the control of valve 30 which is in turn controlled by level controller 31 fitted to separator 20.
  • a selected flow of liquid is diverted from line 28 via line 32 and through valve 33 and flow sensor 34 to a
  • Flow through valve 33 is controlled by a flow controller 35 which is connected to flow sensor 34.
  • This liquid supply via line 32 to a lower part of column reactor 1 provides a route by which reactive sulphur
  • Gas from separator 20 is purged from the plant in line 36 and passes through pressure let-down valve 37 to lines 38 and 39 by means of which it exits the plant.
  • This off-gas contains H 2 S produced as a result of the
  • hydrodesulphurisation treatment and can be subjected to further treatment (e.g. H 2 S removal and subsequent
  • the liquid accumulating in sump 9 is recovered in line 40 and passes through flow control valve 41 to cooler 42.
  • Flow controller 43 controls valve 41.
  • the cooled liquid passes, together with desorbed hydrogen (which is less soluble in cold liquid hydrocarbons than in hot liquid hydrocarbons), by way of line 44 to gas/liquid separator 45.
  • This is fitted with a droplet de-entrainer 46 and a gas return line 47 which leads back to the bottom of column reactor 1.
  • the liquid collecting in separator 45 flows in line 48 through valve 49, which is under the control of level controller 50, to gas-liquid separator 51.
  • This has a droplet de-entrainer 52 and a gas purge line 53 as well as a product recovery line 54.
  • Reference numeral 55 indicates a line by means of which a controlled amount of H 2 S or of an active sulphur-containing material, such as CS 2 , COS, an alkyl mercaptan of formula RSH, an alkyl sulphide of formula RSR, or a dialkyl disulphide of formula RS-SR, in which R is an alkyl group such as n-butyl, can be supplied, conveniently in the form of a solution in a hydrocarbon solvent, as necessary to the hydrodesulphurisation plant as will be described further below.
  • an active sulphur-containing material such as CS 2 , COS, an alkyl mercaptan of formula RSH, an alkyl sulphide of formula RSR, or a dialkyl disulphide of formula RS-SR, in which R is an alkyl group such as n-butyl
  • the liquid feedstock supplied in line 5 passes through the reactor 1 and finally exits the plant in line 53.
  • the organic sulphur compounds are largely converted to H 2 S some of which exits the plant in line 53 dissolved in the liquid product. Separation of H2S from the liquid product can be effected in known manner, e.g. by stripping in a downstream processing unit (not shown) .
  • a suitable amount of a sulphur- containing material preferably H 2 S, CS 2 , COS, or an active organic sulphur-containing material such as an alkyl
  • mercaptan e.g. n-butyl mercaptan
  • dialkyl sulphide such as di-n-butyl sulphide
  • dialkyl disulphide e./g.
  • di-n-butyl disulphide is supplied, conveniently as a solution in a hydrocarbon solvent, in line 54 in order to boost the sulphur content of the feed to the respective tray 2.
  • CS 2 COS, alkyl mercaptans, dialkyl sulphides and dialkyl disulphides are readily and rapidly converted to H 2 S, it can be ensured that the catalyst charge on each tray 2 of reactor 1 remains adequately sulphided so as to remove essentially all risk of hydrocracking occurring in reactor 1.
  • Figure 2 illustrates a design of tray 2 suitable for use in a relatively small scale reactor 1.
  • a frusto-conical partition or diaphragm 70 extends within wall 71 of reactor 1 and closes off the cross section of reactor 1 completely except for a downcomer 72 for liquid and a gas upcomer 73.
  • the slope of frusto-conical diaphragm 70 is equal to or greater than the angle of repose of the solid particulate hydrodesulphurisation catalyst under the liquid present on tray 2.
  • Gas upcomer 73 includes an axial tube 74 which is open at its upper end and which is covered by a bubble cap 75.
  • An annular member of mesh 76 prevents catalyst
  • a cylindrical baffle 77 surrounds bubble cap 75
  • a screen 79 is fitted to the top of downcomer 72 to return catalyst particles on tray 2.
  • Reference numeral 80 indicates the downcomer from the next higher tray 2 (not illustrated).
  • Baffle 77 promotes agitation of the
  • baffle 77 is not critical but should generally be between one third and three quarters of the vertical height between diaphragm 70 and liquid surface 78. It is preferred that baffle 77 should be placed in a
  • the liquid flow is generally upward whilst outside baffle 77 the general direction of liquid flow is downward.
  • thearea of the zone inside baffle 77 approximately equals the sum of the area outside baffle 77.
  • An anti-suckback valve 81 is fitted to gas upcomer 73.
  • the temperature of the liquid and catalyst on tray 2 can be controlled by means of heat exchanger coil 82.
  • FIG. 3 illustrates an alternative construction of tray 2 of reactor 1 of the plant of Figure 1.
  • horizontal diaphragm or partition 100 extends within wall 101 of reactor 1 and closes off the cross section of reactor 1 completely except for a downcomer 102 for liquid and a gas upcomer 103.
  • Partition 100 has an axial frusto-conical part
  • Tray 2 can thus retain a volume of liquid whose surface is indicated at 106 and whose volume is determined by the height of the overflow level of downcomer 102 above the partition 100.
  • Each tray 2 also supports a charge of a solid sulphided hydrodesulphurisation catalyst whose particles are indicated diagrammatically ait 107. Such particles 107 are kept in suspension in the liquid on tray 2 as a result of agitation caused by the upcoming gas as will be described below.
  • the top of downcomer 102 is provided with a screen 108.
  • 105 is equal to or greater than the angle of repose of the solid particulate catalyst under the liquid on tray 2.
  • Gas upcomer 103 conducts upcoming gas to a
  • Annular draught shrouds or baffles 112 and 113 are positioned within the body of liquid on tray 2, one inside and one outside circular sparger 109 to promote agitation of the liquid/catalyst suspension by the upcoming gas.
  • the vertical extent of shrouds 112 and 113 is not critical but should generally be between one third and three quarters of the vertical height between diaphragm 100 and liquid surface 106. It is preferred that shrouds 112 and 113 should be placed in a symmetrical or near symmetrical vertical
  • the area of the annular zone between shrouds 112 and 113 approximately equals the sum of the areas inside shroud 112 and outside shroud 113.
  • Reference numeral 114 indicates a downcomer from the next tray above the one illustrated in Figure 3.
  • the liquid level in downcomer 114 is indicated at 115, the height H of this liquid level above liquid level 116 on tray 2 being fixed by the liquid level on the tray which feeds downcomer 114 (i.e. the tray above the illustrated tray 2) plus the pressure drop through the sparger 109 on that tray (i.e. the one above the illustrated tray 2) and the
  • the temperature on tray 2 of Figure 3 can be controlled by means of a heat exchanger coil 117.
  • heat exchanger 117 is omitted but an external heat exchanger is connected to the column reactor through which liquid drawn from tray 2 can be pumped for temperature control purposes.
  • the invention is further illustrated in the following Example.
  • the liquid feedstock consists of a solution of dibenzothiophene (DBT) in normal hexadecane (114 grams of DBT per litre of solution) which is stored in a feed tank 201.
  • the feed tank 201 is charged with previously prepared solution via line 202 and then purged with dry nitrogen via lines 202 and 203.
  • the feed tank 201, delivery line 204, metering pump 205 and transfer line 206 are located in a circulating hot air chamber (not shown) thermostated at 50°C +/- 5°C to avoid any risk of solid formation (since the melting point of n-hexadecane is about 20°C).
  • the flow of liquid to a column reactor 207 is effected by metering pump 205 and checked from time to time by a burette in the hot air chamber (also not shown).
  • the transfer line 206 is wound with an electrical resistance heater 208 so that the feed liquid can be preheated before entering the upper part of column reactor 207.
  • Column reactor 207 consists of a vertical metal cylinder 2.0 metres high and 7.5 cm in internal diameter containing eight reaction tray sections 209 to 216. (The construction of one of trays 209 to 216 is shown in more detail in Figure 5 and is further described below). Hydrogen gas is supplied in line 212 to the lower part of reactor 207 (above the liquid level in its sump 218) and the desired hydrogen flow is obtained by adjustment of a mass flow controller 219.
  • reactor 207 The whole of reactor 207 is enclosed in an
  • Liquid proceeds downwards from the uppermost reaction tray 209 to lowermost reaction tray 216 by
  • Liquid collects in sump 218 at the base of reactor 207, is discharged from the system by line 220, and is cooled by cooler 221, through which water at approximately 45°C is passed, under the control of valve 222 operated by level controller 223. Samples of the liquid are collected for analysis from line 224.
  • a gas phase leaves reactor 207 by line 225 and is cooled by condenser 226 which is supplied with water at 40°C and the cooled gas and condensate pass via line 227 to drum 228.
  • the gas phase then passes through line 229 and
  • upstream pressure control valve 230 which sets the overall system operating pressure.
  • the gas passes on to analytical flow measurement equipment and a flare (all not shown).
  • the liquid collecting in drum 228 can be returned to tray 209 by line 231 under the control of valve 232 operated by a level sensor 233 on drum 228 or a sample can be withdrawn via line 234 and hand operated valve 235.
  • FIG. 5 An example of a design for one of the reaction trays 209 to 216 is shown in Figure 5.
  • the vertical walls of the reactor column axe shown by the numerals 240.
  • the tray is also fitted with a charge/discharge tube 241 which is fitted with a block valve 242 used for the
  • reactor column 207 is closed by a frusto-conical diaphragm represented in vertical cross section by the numerals 243 and 244.
  • the sloping part of the diaphragm 243 makes an angle of 30° to the horizontal.
  • the horizontal part of the diaphragm 244 is 4 cm in diameter and is pierced by vertical tubes of 4mm internal diameter at two locations.
  • Tube 245 passes through the diaphragm on the vertical axis of the reactor and projects upward into bubble cap 246 for a distance of 22 cm.
  • the projection of tube 243 below the lower surface of horizontal portion 244 is small and can be zero.
  • Bubble cap 246 is 20 mm in external diameter; a 2 mm gap between the lower edge of bubble cap 246 and the upper surface of horizontal portion 244 is closed by screen material 247 consisting of fine stainless steel mesh to prevent catalyst particles entering the inner part of bubble cap 246.
  • Tube 248 starts at a level 9 cm above horizontal portion 244 and proceeds downward to finish in the space below portion 244. It is capped by mesh 249 in order to prevent ingress of catalyst particles.
  • the level of the top of tube 248 determines the level of liquid 250 on the tray.
  • the lower end of tube 248 is below the liquid level on the tray beneath (or in the case of tray 216 the lower end of tube 248 is below the liquid surface in the sump 218 of the reactor 207).
  • the tray i.e. one of the trays 209 to 216 receives liquid from the tray above by a tube 248 as described above (or in the case of tray 209 from the liquid feed line 206); liquid overflows through catalyst screen material 249 and passes down to the next tray below. Gas passes through tube 245, the inner part of bubble cap 246, screen 247 and bubbles through the liquid on the tray; the agitation created by the bubbles maintains catalyst
  • vent line 229 is opened to the atmosphere by opening a bypass line around valve 230 (not shown).
  • each tray 209 to 216 is charged with catalyst slurry through line 241. In this way there is charged to each of the trays 209 to 216 35 cm 3 of 0.1 to 0.5 mm size range catalyst in 290 cm 3 of n-hexadecane.
  • the catalyst is sulphided CoO-MoO 3 / ⁇ amma-alumina which has been previously reduced in hydrogen, cooled and immersed in n-hexadecane. 45 cm of n-hexadecane are used to wash any catalyst in line 241 into the tray.
  • Valve 242 is then closed. A flow of nitrogen is established through line 217 and allowed to pass up column 207 and to vent to atmosphere via line 229. The nitrogen flow is changed to hydrogen and the apparatus is slowly pressurised to 35 bar (absolute), the column heater being used to increase the temperature from 30oC to 325°C over 4 hours.
  • the product liquid in line 224 is sampled from time to time and analysed for dibenzothiophene by gas liquid chromatography. After twelve hours of steady operation the analysis shows that 99.1% of the dibenzothiophene has been converted to sulphur free products and only non-quantifiable traces of the tetrahydro- and hexahydro-derivatives of dibenzothiophene can be seen on the chromatographic
  • dibenzothiophene conversion progressively increases to 99.5% and stabilises.
  • Figure 6 is a graph indicating diagrammatically the effect of these various factors upon an aromatics hydrogenation reaction.
  • Figure 6 there is plotted percentage aromatics in the product versus temperature for a given hydrogen partial pressure.
  • Line A-A' in Figure 6 indicates the variation with temperature, at a fixed
  • Line B-B' represents the equilibrium limited aromatics content in the product from the same reaction system as a function of temperature.
  • the line XY (or X'Y') represents the excess aromatics content of the product and hence provides a measure of the driving force required by the catalyst.
  • the point 0 represents the lowest aromatics content obtainable from the given system and is obtainable only by selecting a combination of the most favourable kinetics and the less favourable equilibrium as the temperature increases.
  • the activity of the catalyst can be enhanced in some way, e.g. by controlling the degree of sulphiding thereof, then a new curve, such as C-C, can be obtained, with a new lower optimum aromatics level (point 0')

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  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Abstract

Un procédé d'hydrodésulfuration servant à effectuer l'hydrodésulfuration en continu d'une charge d'hydrocarbure liquide contenant du soufre consiste à : a) ménager une zone d'hydrodésulfuration maintenue dans des conditions d'hydrodésulfuration et comprenant un réacteur à colonne pourvu d'une multiplicité de plateaux de réaction montés les uns au-dessus des autres, chaque plateau formant un étage de réaction respectif conçu pour contenir un volume de liquide prédéterminé et une charge d'un catalyseur d'hydrodésulfuration solide et contenant du sulfure, des éléments d'écoulement de liquide associés à chaque plateau de réaction et conçus pour permettre au liquide de descendre le long du réacteur à colonne à partir de ce plateau mais pour y retenir le catalysdeur solide, et des éléments de montée de gas associés à chaque plateau de réaction et conçus pour permettre au gaz d'entrer dans le plateau d'en bas et pour agiter le mélange de liquide et de catalyseur sur ce plateau; b) alimenter le plateau supérieur de ladite multiplicité de plateaux de réaction en une charge d'hydrocarbure liquide contenant de l'hydrogène; c) fournir du gaz contenant de l'hydrogène au-dessous du plateau inférieur de ladite multiplicité de plateaux de réaction; d) permettre au liquide de s'écouler vers le bas, de plateau en plateau, à travers le réacteur à colonne; e) permettre au gaz contenant de l'hydrogène de s'élever de plateau en plateau à travers le réacteur à colonne; f) récupérer un effluent gazeux contenant du H2S produit par hydrodésulfuration du plateau supérieur de ladite multiplicité de plateaux de réaction; et g) récupérer un produit d'hydrocarbure liquide de ladite multiplicité de plateaux de réaction.
PCT/GB1990/001705 1989-05-10 1990-11-07 Procede d'hydrodesulfuration WO1992008771A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
RU9093005231A RU2066339C1 (ru) 1990-11-07 1990-11-07 Способ непрерывной гидродесульфурации
AU66364/90A AU658130B2 (en) 1990-11-07 1990-11-07 Hydrodesulphurization process
PCT/GB1990/001705 WO1992008771A1 (fr) 1989-05-10 1990-11-07 Procede d'hydrodesulfuration
KR1019930701364A KR930702471A (ko) 1990-11-07 1990-11-07 수소화 탈황법

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB898910712A GB8910712D0 (en) 1989-05-10 1989-05-10 Process
PCT/GB1990/001705 WO1992008771A1 (fr) 1989-05-10 1990-11-07 Procede d'hydrodesulfuration

Publications (1)

Publication Number Publication Date
WO1992008771A1 true WO1992008771A1 (fr) 1992-05-29

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PCT/GB1990/001705 WO1992008771A1 (fr) 1989-05-10 1990-11-07 Procede d'hydrodesulfuration

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WO (1) WO1992008771A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103347602A (zh) * 2011-09-22 2013-10-09 戴维加工技术有限公司 设备和方法
WO2022155611A1 (fr) * 2021-01-16 2022-07-21 Alternative Petroleum Technologies, Inc. Système et procédé de désulfuration de combustibles hydrocarbonés

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3425810A (en) * 1965-05-03 1969-02-04 Chevron Res Hydrotreating apparatus
GB2005151A (en) * 1977-10-07 1979-04-19 Shell Int Research Apparatus for the catalytic treatment of hydrocarbons
WO1990013612A1 (fr) * 1989-05-10 1990-11-15 Davy Mckee (London) Limited Procede d'hydrodesoufrage en plusieurs etapes

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3425810A (en) * 1965-05-03 1969-02-04 Chevron Res Hydrotreating apparatus
GB2005151A (en) * 1977-10-07 1979-04-19 Shell Int Research Apparatus for the catalytic treatment of hydrocarbons
WO1990013612A1 (fr) * 1989-05-10 1990-11-15 Davy Mckee (London) Limited Procede d'hydrodesoufrage en plusieurs etapes

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103347602A (zh) * 2011-09-22 2013-10-09 戴维加工技术有限公司 设备和方法
WO2022155611A1 (fr) * 2021-01-16 2022-07-21 Alternative Petroleum Technologies, Inc. Système et procédé de désulfuration de combustibles hydrocarbonés
US11912944B2 (en) 2021-01-16 2024-02-27 Alternative Environmental Technologies Sulfex Corp. System and method for desulfurization of hydrocarbon fuels

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