United States Patent c19J
`Renard
`
`I IIIII IIIIIIII Ill lllll lllll lllll lllll lllll lllll lllll lllll 111111111111111111
`US005417846A
`5,417,846
`[11) Patent Number:
`May 23, 1995
`[45) Date of Patent:
`
`[75)
`
`[54) HYDROTREATMENT MEIBOD FOR A
`PETROLEUM RESIDUE OR HEAVY OIL
`WITH A VIEW TO REFINING THEM AND
`CONVERTING THEM TO LIGHTER
`FRACTIONS
`Inventor: Pierre Renard, Saint Nom La
`Breteche, France
`lnstitut Francais du Petrole,
`Rueil-Malmaison, France
`[21) Appl. No.: 46,506
`Apr. 14, 1993
`[22) Filed:
`
`[73) Assignee:
`
`Related U.S. Application Data
`[63) Continuation of Ser. No. 677,179, Mar. 29, 1991, aban(cid:173)
`doned.
`Foreign Application Priority Data
`[30)
`France ................................ 90 04153
`Mar. 29, 1990 [FR]
`Int. Cl.6 .............................................. Cl0G 23/02
`[51)
`[52) U.S. Cl . ............................... 208/210; 208/251 H;
`208/211; 208/212
`[58) Field of Search ................. 208/210, 211, 89, 212,
`208/251 H
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`3,716,479 2/1973 Weisy et al ......................... 208/210
`3,809,644 5/1974 Johnson et al ...................... 208/210
`3,900,390 8/1975 Adams et al ........................ 208/210
`3,901,792 8/1975 Walk et al ........................... 208/210
`3,968,026 7/1976 Frayer et al ........................ 208/210
`4,053,391 10/1977 Paraskos et al ..................... 208/210
`
`4,054,508 10/1977 Milslun ................................ 208/210
`4,118,310 10/1978 Frayer et al ........................ 208/210
`4,925,554 5/1990 Sato et al ............................ 208/210
`FOREIGN PATENT DOCUMENTS
`0113297 7/1984 European Pat. Off ..
`2124252 7/1983 United Kingdom .
`Primary Examiner-Helane Myers
`Attorney, Agent, or Firm-Millen, White, Zelano, &
`Branigan
`
`ABSTRACT
`[57)
`The invention concerns a hydro treatment method in at
`least two stages, for a heavy hydrocarbon fraction con(cid:173)
`taining asphaltenes, sulphur impurities and metallic
`impurities, wherein:
`a) in at least one first stage described as hy(cid:173)
`drodemetallization, the hydrocarbon charge and
`hydrogen are passed over a hydrodemetallization
`catalyst,
`b) in at least one subsequent stage described as hy(cid:173)
`drodesulphurization, the product of stage a) and
`hydrogen are passed over a hydrodesulphurization
`catalyst.
`The invention, in which the hydrodemetallization stage
`comprises one or more zones each containing hy(cid:173)
`drodemetallization catalyst operating in a fixed bed, is
`characterised in that this zone or these zones are pre(cid:173)
`ceded by two protective zones arranged in parallel,
`each containing a fixed bed of a hydrodemetallization
`catalyst, the two protective zones operating alternately.
`
`16 Claims, 2 Drawing Sheets
`
`1 of 8
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`REFINED TECHNOLOGIES, INC.
`EXHIBIT 2006
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`U.S. Patent
`
`May 23, 1995
`
`Sheet 1 of 2
`
`5,417,846
`
`FIG.1
`
`28
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`29
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`FIG.2
`__ 21
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`26
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`__ 28
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`29
`
`FIG.3
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`- 52 -
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`- 53 -
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`2 of 8
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`U.S. Patent
`
`May 23, 1995
`
`Sheet 2 of 2
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`5,417,846
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`1
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`5,417,846
`
`HYDROTREATMENT METHOD FOR A
`PETROLEUM RESIDUE OR HEAVY OIL WITH A
`VIEW TO REFINING THEM AND CONVERTING
`THEM TO LIGHfER FRACTIONS
`
`2
`a) FIXED BED METHODS
`This method is an improvement to the methods with
`fixed beds of catalyst. In such methods (see FIG. 1), the
`5 charge arriving along line 1 circulates through a plural(cid:173)
`ity of fixed bed reactors arranged in series, the first
`reactor or reactors 26 or 27 being used chiefly for hy(cid:173)
`This is a continuation of U.S. Ser. No. 07/677,179,
`drodemetallization of the charge (so-called HDM stage)
`filed Mar. 29, 1991, now abandoned.
`and a hydrodesulphurization part, the last reactor or
`BACKGROUND OF THE INVENTION
`10 reactors 28 or 29 being used for deep refining and par(cid:173)
`ticularly hydrodesulphurization of the charge (so-called
`The invention concerns refining and conversion of
`HDS stage). The effluents are drawn off from the last
`heavy liquid hydrocarbon fractions containing inter alia
`HDS reactor 29 through the pipe 21.
`asphaltenes and sulphur and metallic impurities, such as
`Such methods most frequently use specific catalysts
`atmospheric residues, vacuum residues, deasphalted
`15 adapted to each stage, under mean operating conditions
`oils, pitches, asphalts mixed with an aromatic distillate,
`of about 150 to 200 bars pressure and about 370° to 420°
`coal hydrogenates or heavy oils from any source and
`particularly from asphaltic sands or oil shales.
`C. temperature.
`For the HDM stage the ideal catalyst must be capable
`These charges which can be treated according to the
`of treating charges rich in asphaltenes, while at the same
`invention generally contain at least 100 ppm by weight
`time having a high demetallizing power associated with
`of metals (nickel and/or vanadium), at least 1 % by 20
`a high capacity for retaining metals and great resistance
`weight of sulphur and at least 2% by weight of asphal(cid:173)
`to coking. Such a catalyst has been developed on a
`tenes.
`particular macroporous carrier (with a "sea urchin"
`The object of the catalytic hydrotreatment of these
`structure) which gives it the precise properties required
`charges is both to refine, i.e. substantially reduce, their
`at this stage (Patents EP-B-113297 and EP-B-113284):
`content of asphaltenes, metals, sulphur and other impu- 25
`Demetallization rate of at least 80 to 90% at the
`rities, while at the same time improving the hydrogen to
`HDM stage;
`carbon ratio (H/C) and converting them more or less
`Metal retaining capacity of over 60% relative to the
`partially to lighter cuts. The various effluents thus ob(cid:173)
`weight of new catalyst, enabling longer operating
`tained can act as bases for the production of high quality
`cycles to be obtained;
`fuel, gas oil and petrol, or charges for other units such 30
`Great resistance to coking even at temperatures over
`as residue cracking.
`· 400° C., thus helping to lengthen the cycle, which
`The problem posed by the catalytic hydrotreatment
`is often limited by an increase in the pressure drop
`of these charges stems from the fact that the impurities
`and loss of activity due to coke production, and
`are deposited bit by bit on the catalyst in the form of
`enabling the essential part of the heat conversion to
`metals and coke, and tend to deactivate and rapidly clog 35
`be obtained at this stage.
`the catalytic system, necessitating a stoppage for its
`For the HDS stage the ideal catalyst must have
`replacement.
`strong hydrogenating power so as to carry out deep
`Methods of hydrotreatment for this type of charge
`refining of the products: desulphurization, continued
`must therefore be designed to allow the longest possible
`demetallization, lowering of the Conradson carbon and
`operating cycle without stopping the unit. The objec- 40
`the asphaltene content. Applicants have developed such
`tive is to achieve a one year operating cycle at the mini(cid:173)
`a catalyst (Patents EP-B-113297 and EP-B-113284)
`mum, or a minimum of eleven months' continuous oper(cid:173)
`which is particularly well adapted to treating this type
`ation plus a maximum of one month's stoppage to re(cid:173)
`of charge.
`place the whole catalytic system.
`The disadvantage of this type of catalyst with high
`PRESENT STATE OF THE ART
`hydrogenating power is that it is deactivated rapidly in
`the presence of metals or coke. Therefore if an appro-
`There are various existing treatments for this type of
`priate HDM catalyst, capable of functioning at rela-
`charge. They have so far been carried out:
`tively high temperature to carry out the essential part of
`either in methods with fixed beds of catalyst, for
`example, the HYV AHL-E process oflnstitut Fran- 50 the conversion and demetallization, is associated with
`an appropriate HDS catalyst-which, being protected
`cais du Petrole;
`from metals and other impurities by the HDM catalyst,
`or in methods comprising at least one reactor allow-
`can be operated at a relatively low temperature, thereby
`ing for quasi continuous replacement of catalyst,
`encouraging deep hydrogenation and limitation of
`such as the HYV AHL-M fluidized bed method of
`55 coking-the global refining performance finally ob-
`IFP.
`tained is better than that obtained with a single catalytic
`BRIEF DESCRIPTION OF THE DRAWINGS
`system and better than that obtained with a similar
`HDM/HDS arrangement using an increasing tempera-
`Various other objects, features, and attendant advan(cid:173)
`ture profile, which leads to rapid coking of the HDS
`tages of the present invention will be more fully appre(cid:173)
`catalyst.
`ciated as the same becomes better understood when 60
`The importance of fixed bed methods is that a good
`considered in conjunction with the accompanying
`refining performance is obtained due to the great cata(cid:173)
`drawings, in which like reference characters designate
`lytic effectiveness of fixed beds. On the other hand,
`the same or similar parts throughout the several views
`when the charge has more than a certain metal content
`and wherein:
`(e.g. 100 to 150 ppm), in spite of using the best catalytic
`FIGS. 1-4 are flowsheets or prior art systems for 65
`systems, the performance and above all the operating
`hydrotreating the above-described charges, and
`time of the process is found to become inadequate: the
`FIG. 5 is a flowsheet illustrating a preferred compre(cid:173)
`reactors (particularly the first HDM reactor) rapidly
`hensive embodiment of the present invention.
`
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`3
`become charged with metals and thus deactivated.
`Temperatures are increased to compensate for the deac(cid:173)
`tivation, thus encouraging coke formation and an in(cid:173)
`crease in the pressure drop. Moreover the first catalytic
`bed is known to be liable to clog fairly rapidly due to 5
`the asphaltenes and sediments contained in the charge
`or as a result of operating trouble.
`Consequently the unit has to be stopped every 3 to 6
`months at the minimum to replace the first catalytic
`beds which are deactivated or clogged. This operation 10
`may take up to 3 weeks, with a corresponding reduction
`in the operating factor of the unit.
`
`15
`
`30
`
`b) FLUIDIZED BED OR BOILING BED
`METHODS
`Attempts have been made to deal with these disad(cid:173)
`vantages of fixed bed arrangements in different ways.
`Thus one idea has been to install one or more 24-A
`fluidized bed reactors at the head of the HOM stage (see
`e.g. FIG. 2) (Patents U.S. Pat. No. 3,910,834 or GB-B- 20
`2124252A). The fluidized beds may operate co-cur(cid:173)
`rently (e.g. SHELL's HYCON process) or counter-cur(cid:173)
`rently (e.g. HYV AHL-M process). In this way fixed
`bed reactors are protected, while carrying out part of
`2
`the demetallization and filtering the particles contained 5
`in the charge which may lead to clogging. In addition
`the quasi continuous replacement of catalyst in the flu(cid:173)
`idized bed reactor or reactors (with spent catalyst
`drawn off through pipe 61 and fresh catalyst introduced
`through pipe 60) avoids stopping the unit every 3 to 6
`months.
`The disadvantage of these fluidized bed technologies
`is finally that their performance and effectiveness are
`rather lower than those of fixed beds of the same size, 35
`that they cause wear on the circulating catalyst which
`may lead to blockage of downstream fixed beds, and
`that-particularly under
`the operating conditions
`used-the dangers of coking and thus of the formation
`of conglomerates of catalyst is far from negligible in 40
`these heavy charges, particularly if there is operating
`trouble; this may prevent circulation of the catalyst
`either in the reactor or in the lines for tapping spent
`catalyst, and finally lead to stoppage of the unit to clean
`the reactor and tapping lines.
`Another idea has been to use one or more boiling or
`"bubbling" beds arranged in series (the H-OIL process
`of the Hydrocarbon Research Institute or the LC-FIN(cid:173)
`ING process) of Ste Lymmus, U.S. Pat. No. 3,809,644.
`The carrying out of this technology has now been mas- 50
`tered and, particularly to a certain degree, the forma(cid:173)
`tion of aggregates due to coking does no harm since the
`grains of catalyst are always in motion. The catalyst is
`replaced quasi continuously without stopping the unit.
`On the other hand, the movement of catalyst causes 55
`serious wear, which makes it impossible to have any
`fixed bed reactor downstream of the boiling bed. Above
`all, the mixing of fresh and spent catalyst and the mixing
`of effluents with charge make the performance substan(cid:173)
`tially worse than that of the fixed bed (quality of prod- 60
`ucts), and make the catalyst ineffective (high catalyst
`consumption). FIG. 3 illustrates 3 reactors 51, 52, 53 in
`series, the arrival of fresh charge through the pipe 1 at
`the bottom of the first reactor 51 through which the
`charge passes, the discharge of effluent drawn off at the 65
`top of the last reactor 53 through which the charge
`passes, and the respective catalyst inlets 54, 55 and 56
`and outlets 57, 58 and 59 in the 3 reactors in the figure.
`
`45
`
`5,417,846
`
`4
`c) EXISTING IMPROVEMENTS IN FIXED BED
`METHODS
`In order to preserve the excellent performance of
`fixed beds while maintaining an acceptable operating
`factor, a fixed bed protective reactor (reacteur de
`garde) (space velocity VVH=2 to 4) has been added
`before the HOM reactors U.S. Pat. Nos. 4,118,310 and
`3,968,026). The protective reactor 24 can most fre-
`quently be short-circuited, particularly by using a valve
`31 (see FIG. 4). This gives the main reactors temporary
`protection from clogging. When the protective reactor
`is clogged it is short-circuited, but the next main reactor
`(26) may then become clogged in turn and lead to stop(cid:173)
`page of the unit. In addition the small size of the protec(cid:173)
`tive reactor (24) does not produce good demetallisation
`of the charge, so the main HOM reactors (reactors 26
`and 27) are ill-protected from metal deposits in the case
`of charges rich in metals (over 150 to 200 ppm). There
`is consequent accelerated deactivation of the reactors,
`leading to over-rapid stoppages of the unit, and hence
`the operating factors are still inadequate.
`
`SUMMARY OF THE INVENTION
`In the present invention it has finally been discovered
`that, in order to associate the high performance of the
`fixed bed with a high operating factor for treating
`charges with a high metal content (100 to 400 ppm but
`preferably 100 to 300 ppm) an excellent method consists
`of:
`using a fixed bed arrangement comprising an HDM
`stage then an HOS stage, the HOM stage being made
`up of one or more fixed bed HOM zones, preceded by
`two protective HOM zones, also fixed bed but arranged
`in parallel so that they can be used alternately; a single
`protective zone being in operation and gradually be(cid:173)
`coming charged with metals, coke, sediments and .vari(cid:173)
`ous other impurities, while the other protective zone is
`disconnected from the unit and standing by, filled with
`fresh HDM catalyst;
`exchanging the protective zones when the first is
`completely saturated with metals and various impuri(cid:173)
`ties, that is to say, putting the protective zone contain(cid:173)
`ing the fresh catalyst into operation while disconnecting
`the protective zone previously in operation, containing
`the spent catalyst saturated with metals and various
`impurities;
`preferably using a special processing section enabling
`the protective zones to be exchanged while in opera(cid:173)
`tion, that is to say, without stopping the unit: firstly a
`system operating at moderate pressure (from 10 to 50
`bars but preferably from 15 to 25 bars) enables the fol(cid:173)
`lowing operations to be carried out on the disconnected
`protective reactor: washing, stripping, cooling before
`the spent catalyst is discharged, then heating and sultur(cid:173)
`ization when the fresh catalyst has been charged; next
`another pressurizing/depressurizing, valve/tap system
`with the appropriate technology effectively enables the
`protective zones to be exchanged without stopping the
`unit, that is to say, without affecting the operating fac(cid:173)
`tor, since all the operations of washing, stripping, dis(cid:173)
`charging the spent catalyst, recharging the fresh cata(cid:173)
`lyst, heating and sulphurization take place in the discon(cid:173)
`nected protective reactor or zone;
`preferably also using the following space velocities
`per hour (VVH):
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`VVH (h-1)
`0.2-0.5
`
`0.2-0.5
`0.10-0.25
`
`Preferably
`0.3-0.4
`
`0.3-0.4
`0.15-0.20
`
`10
`
`35
`
`5
`
`5,417,846
`
`Total HDM stage:
`(including protective reactor)
`Total HDS stage:
`Globally (HDM + HOS):
`
`6
`drodemetallization reactor 5 with a fixed bed 25 of
`catalyst. The effiuent is discharged through a pipe 27,
`valve 8 and lines 9 and 13 to a main hydrodemetalliza(cid:173)
`tion reactor 14 containing a fixed bed 26 of catalyst. The
`5 effiuent from the reactor 14 is drawn off through a pipe
`15 then passed into another hydrodemetallization reac(cid:173)
`tor 16 where it travels through a fixed bed 27 of cata-
`lyst. The effiuent from the reactor 16 is drawn off
`The preferred feature of the invention here comprises
`through a pipe 17 and enters the first hydrodesulphuri-
`operating the working protective zone or reactor at a
`zation reactor 18 where it travels through a fixed bed 28
`relatively low VVH (0.5 to 1.5 and preferably 0.8 to
`of catalyst. The effiuent from the first hydrodesulphuri-
`1.2), contrary to other methods using smaller protective
`zation reactor 18 goes through a pipe 19 to the second
`reactors, particularly that described in U.S. Pat. No.
`hydrodesulphurization reactor 20 where it passes
`3,968,026 where the protective reactors used (a) are
`through a fixed bed 29 of catalyst. The final effiuent is
`smaller and (b) operate simultaneously and not alter-
`nately. The VVH value (0.8 to 1.2) has been selected to 15 drawn off through a pipe 21.
`When the working protective reactor 5 is no longer
`obtain the maximum HOM while controlling the reac-
`operating, the charge in the pipe 1 is then passed
`tion temperature (limiting exothermicity).
`through a pipe 23, valve 31 and pipe 4 into the other
`It has been found that the following results can be
`protective hydrodemetallization reactor 6 containing a
`obtained by using the appropriate HDM/HDS cata-
`lysts, preferably those produced by Patents EP-B~ 20 fixed bed 24 of catalyst. The effluent from the protec-
`tive reactor 6 passes through a pipe 10, valve 11 and
`113297 and EP-B-113284, and the features of the inven-
`pipes 12 and 13 to the hydrodemetallization reactor 14,
`tion described above:
`and the effiuent from the reactor 6 then continues to
`Over 50% of HOM in the charge in the protective
`circulate as explained above.
`zone or reactor (more specifically from 50 to 60% of
`HOM) owing to the low VVH selected and the effec- 25 A section 30 is equipped with appropriate circulating,
`heating, cooling and separating means which operate
`tiveness of the HDM catalyst, in contrast with prior art
`independently of the reaction section. By means of pipes
`methods which did not allow more than about 35% of
`41 32 and 33 valves 34 and 35 valves 36 and 37 and
`HOM in the protective reactor. Moreover owing to the
`pi;es 38 39 ~d 40 the section 30 makes it possible to
`high metal retaining capacity of the catalyst (over 60%
`of metals deposite?- relative to the weight of n~w cata- 30 carry o~t the operations for preparing the fresh catalyst
`contained in the protective reactor 6 just before it is
`lyst), each protective zone 0 ~ reactor can function from
`connected, with the unit working, to replace the protec-
`2 to 6 months and ~ore particularly from 3 to 4 months
`tive reactor 5, namely: preheating the protective reactor
`before the pro_tective zones or reactors ~ave to be ~x-
`changed, that is to sa~, ?efore the operatmg ~rot7ctive
`6, sulphurizing the catalyst 24 and putting it under the
`pressure and temperature conditions required for the
`zone or reactor contaming the spent cataly~t is discon-
`_
`th
`·
`f O of exch
`the
`Whe
`exch
`nected and replaced by the other protective reactor
`e pro
`angmg
`ol?era i _n
`n
`. ange.
`containing fresh catalyst.
`tective reactors 5 and 6 1S earned out by means of the set
`.
`.
`An operating cycle of at l~t 11 months for the mam
`of the valves 2 31 8 and 11 the section 30 this time
`.
`'
`'
`. '
`.
`HOM and HOS reactors, owmg to the excellent protec-
`tion which the protective reactor gives them against 40 ~akes it possible to carry o~t the_operations of_process-
`metals (over 50% of HOM) and against problems of mg th~ spen~ catalyst co~tamed m th: protective reac-
`tor 5 ~ediate~y after it has bee~ disconne~te~ from
`clogging with sediments, coke and other impurities.
`the reaction section, namely: was~g and s~ppmg the
`At the end of the cycle of at least 11 months, obtained
`spen~ ca~yst 25 under t~e requrred cond~tions, th7n
`even with charges rich in metals (lOO to 400 ppm, pref-
`erably 150 to 300 ppm), the unit has to be stopped for 45 coo~g it before proceedmg to the o~era~10~ of dis-
`chargmg the spent catalyst and replacmg it with fresh
`total replacement of the catalyst contained in the main
`catalySt-
`.
`.
`reactors. Since this operation can conveniently be car-
`The catalysts m !he protective reacto~s ar~ preferably
`ried out in less than a month, it is found that by operat-
`the same as those m the hydrodemetallization reactors
`ing in accordance with the invention an operating fac-
`tor of at least 0.91 (i.e. 11 months out of 12), is obtained; 50 14 ~d 16.
`I_t is ~so preferable for the catalysts to ~e those ~e-
`this is substantially better than the working factor for
`scnbed m Patent EP-B-987~. They con~ a carn:r
`prior art fixed bed processes and at least equivalent to
`and from 0.1 to 30% by weight, counted m metallic
`processes using one or more fluidized beds. In addition
`oxides, of at least one metal or metal compound from at
`the presence of a standby protective reactor full of fresh
`catalyst and always ready to be connected avoids trou- 55 least one of groups V, VI or VIII of the Periodic Table.
`These are in the form of a plurality of juxtaposed con-
`ble which may drastically affect the working protective
`glomerates, each formed by a plurality of acicular tips,
`reactor (e.g. coking as a result of trouble with reactor
`the tips of each conglomerate being directed generally
`control, or clogging as a result of accidental entrain-
`radially of one another and radially of the center of the
`ment of salts or sediments by the charge) and thus helps
`60 conglomerate.
`to maintain a high operating factor.
`This invention more particularly concerns the treat-
`Maintenance of a high refining and conversion per-
`ment of heavy petroleums or heavy petroleum fractions
`formance right through the cycle while the products
`with a high asphaltene content, for the purpose of con-
`are kept stable:
`verting them to less heavy fractions which can more
`over 90% global HOS;
`65 easily be transported or treated by normal refining pro-
`from 90 to 95% global HOM.
`cesses. Coal hydrogenation oils may also be treated.
`FIG. 5 explains the invention briefly by way of illus-
`More particularly, the invention solves the problem
`tration. The charge is passed through line 1 and line 22
`of converting a heavy, viscous oil which is immobile
`to a valve 2 and pipe 3 and into a protective hy-
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`5,417,846
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`8
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`7
`(non transportable) and rich in metal, sulphur and as(cid:173)
`phaltenes and which contains over 50% of constituents
`with a normal boiling point above 520° C., to a stable,
`easily moving (transportable) hydrocarbon product
`with a low content of metals, sulphur and asphaltenes 5
`and only a reduced content, e.g. less than 20% by
`weight, of constituents with a normal boiling point
`above 520° C.
`In an improvement of the present invention the
`charge is mixed with hydrogen and subjected to hy(cid:173)
`droviscoreduction conditions before being passed to the
`protective reactors.
`
`10
`
`Comparison of Methods (at equivalent global VVH):
`Method I
`Method II
`
`90%
`95%
`40%
`
`Global mean HDS
`Global mean HDM
`Mean comversion
`(to 540-)
`VVH protective reactor
`HDM protective reactor
`Continuous operating cycle
`5 months
`Stoppage to replace catalyst
`1 month max.
`Operating factor
`0.83
`((•) protective reactor exchanged every 4 months)
`
`90%
`95%
`40%
`
`1.0(*)
`50%
`II months
`1 month max.
`0.92
`
`Thus it will be seen that in Method II according to
`the invention longer operating cycles and a higher oper-
`ating factor are obtained than if a traditional fixed bed
`method is used; this advantage is all the more marked
`when charges richer in metals are treated. Beyond a
`metal content of 250 ppm, for example, it is not even
`realistic to envisage traditional fixed bed treatment,
`whereas a method according to the invention will en(cid:173)
`able long operating cycles and high operating factors to
`be maintained.
`
`EXAMPLE2
`We have also studied treatment according to the
`invention of existing charges (petroleum residues)
`where the metal content ranges from 130 ppm to 328
`ppm and where there are various difficulties in the treat(cid:173)
`ment. The results obtained are given in the table below:
`
`2
`
`3
`
`4
`
`5.28
`214
`90
`95
`1.0
`50
`
`3.55
`269
`90
`95
`1.0
`55
`
`7.75
`328
`90
`95
`0.8
`65
`
`4.3
`130
`90
`95
`1.2
`50
`
`II
`
`11
`
`II
`
`11
`
`(6)
`
`(4)
`
`(3)
`
`(3)
`
`Charge, case number:
`
`Sulphur content (% by weight)
`Metal content (ppm)
`Global HDS (% by weight)
`Global HDM (% by weight)
`VVH protective reactor
`HDM protective reactor
`(% by weight)
`Continuous operating
`cycle (months)
`Stoppage to replace
`catalyst (months, max.)
`(Protective reactor cycle
`in months)
`Charges:
`Case I: Residue ARABIAN LIGHT
`2: Residue SAFANIYAH
`3: Residue IRANIAN LIGHT
`4: Residue ROSPO MARE
`
`15
`
`45
`
`EXAMPLE 1
`As an example a heavy fraction of the residue type, as
`in Example 1 of European Patent EP-B-113297, is
`treated using catalyst A with a "sea urchin" structure in
`the HDM reactors and catalyst B in the HDS reactors.
`To compare the advantages provided by the inven- 20
`tion, treatment of the charge will be described using the
`following two types of method:
`Method I: traditional fixed bed method comprising a
`first HDM stage followed by a second HDS stage;
`Method II: the method according to the invention, 25
`that is to say, also including a fixed bed HDM stage
`followed by a fixed bed HDS stage, but with the
`HDM stage taking place in at least one fixed bed
`HDM reactor, itself preceded by two protective
`HDM reactors arranged in parallel and used alter- 30
`nately, with one reactor operating and the other
`standing by, disconnected from the unit.
`When the catalyst in the working protective reactor
`has lost its activity and/or is sufficiently blocked with 35
`coke or sediments to be no longer usable, the two pro(cid:173)
`tective reactors are exchanged. The standby reactor is
`connected to the unit while the other, previously work(cid:173)
`ing reactor, is disconnected from it; the exchange takes
`place without stopping the unit, that is to say, without 40
`affecting its operating factor. Also according to the
`invention, a relatively low VVH is selected in each of
`the protective reactors, so as to give the other reactors
`optimum protection from metals and thus maximize
`their operating cycles:
`VVH protective reactors-0.6 to 1.5 and preferably
`0.8 to 1.2
`Global VVH of all reactors (HDM+HDS): 0.10 to
`0.25 and preferably 0.15 to 0.20.
`The low VVH of the protective reactors results in a 50
`volume substantially of the same order of magnitude as
`the other main HDM or HDS reactors; this is in con(cid:173)
`trast with other fixed bed methods using protective
`reactors of smaller volume.
`Charge Treated
`
`"SAFANIYA" vacuum residue
`
`TBP cut:
`Density at 1s· C.:
`Sulphur:
`Conradson carbon:
`C7 asphaltenes:
`Metals (Ni + V):
`
`540+° C.
`1.035
`S.28% by weight
`25% by weight
`11.9% by weight
`214ppm
`
`Operating Conditions are fixed so as to obtain maximum
`conversion compatible with the stability of the prod(cid:173)
`ucts, and a mean HDM of 95%.
`
`I claim:
`1. In a method of hydrotreatment in at least two
`stages, of a heavy hydrocarbon fraction containing
`asphaltenes, sulfur impurities and metallic impurities,
`55 wherein:
`(a) in at least one first hydrodemetallization stage, the
`hydrocarbon charge and hydrogen are passed over
`a hydrodemetallization
`catalyst
`in
`a
`hy(cid:173)
`drodemetallization zone or zones, and
`(b) in at least one subsequent hydrodesulfurization
`stage, the product of stage (a) and hydrogen are
`passed over a hydrodesulfurization catalyst,
`the improvement wherein the hydrodemetallization
`zone or zones is or are preceded by two protective
`65 zones in parallel, each containing a fixed bed of a hy(cid:173)
`drodemetallization catalyst, the two protective zones
`operating only alternately, one off-stream and one on(cid:173)
`stream, and wherein the volume of each protective zone
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`5,417,846
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`9
`has sufficient demetallization capacity to provide suffi(cid:173)
`cient time to permit the off-stream protective zone to be
`treated and placed on-stream, so as to permit the ex(cid:173)
`changing of the protective zones without stopping the
`unit or decreasing the capacity of the unit.
`2. The method of claim 1, wherein each of said pro(cid:173)
`tective zones has substantially the same volume as a
`hydrodemetallization zone.
`3. The method of claim 1, wherein the volume of feed 10
`per volume of catalyst per hour in the working protec(cid:173)
`tive zone is from 0.5 to 1.5.
`4. The method of claim 3, wherein the volume of feed
`per volume of catalyst per hour is from 0.8 to 1.2.
`5. The method of claim 1, wherein the catalyst used in
`the protective zones contains a carrier and from 0.1 to
`30% by weight, counted in metallic oxides, of at least
`one metal or metal compound from at least one of
`groups V, VI or VIII of the Periodic Table, in the form 20
`of a plurality of juxtaposed conglomerates each formed
`by a plurality of acicular tips, the tips of each conglom(cid:173)
`erate being directed generally radially of one another
`and radially of the center of the conglomerate.
`6. The method of claim 1, wherein a processing sec- 25
`tion is associated with the protective zones and enables
`them to be exchanged while in operation, without stop(cid:173)
`ping the unit, said section being regulated so as to pro(cid:173)
`cess the catalyst contained in the off-stream protective 30
`zone at a pressure of 10 to 50 bars.
`
`15
`
`10
`7. The method of claim 6, wherein said pressure is
`from 15 to 25 bars.
`8. The method of claim 1, for treating a charge com(cid:173)
`prising a heavy oil or a heavy oil fraction containing
`5 asphaltenes, wherein the charge is first subjected to
`hydroviscoreduction conditions, mixed with hydrogen,
`before being passed into the protective zones.
`9. The method of claim 1, wherein the charge has a
`metal content of 100-400 ppm.
`10. The method of claim 9, wherein the charge has a
`metal content of more than 250 ppm.
`11. The method of claim 6, wherein the charge has a
`metal content of 100-400 ppm.
`U. The method of claim 11, wherein the charge has
`a metal content of more than 250 ppm.
`13. A method according to claim 1, comprising an
`upstream hydrodemetallization and at least one down(cid:173)
`stream hydrodemetallization zone operating continu-
`ously in series, wherein each hydrodemetallization zone
`is conducted in a separate reactor, the upstream zone
`being preceded by said two protective zones conducted
`in separate reactors.
`14. The method of claim 13, wherein the charge has
`a metal content of 100-400 ppm.
`15. The method of claim 13, wherein the charge has
`a metal content of more than 250 ppm.
`16. A process according to claim 1, wherein the hy(cid:173)
`drodemetallization stage operates at a continuous 100%
`capacity until the hydrodesulfurization stage is shut
`down.
`
`* * * * *
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