HUE030396T2 - Eljárás dízel vagy kerozin részpárlat elõállítására fõleg 4- és 6. szénatomos olefin alapanyagból, két oligomerizációs egység alkalmazásával - Google Patents

Description

Kijárás dízel vagy kerozin részpáriat eibáliítésára főleg 4~ és 6,szénatomos olefin alapanyagtól, két oligömerhációs egység alkalmazásával

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The present Invention is In the field1 of refining processes which make It possible to convert an oiefink: cut having mainly 4 to 6 carhopatoms into a so-called middle distillate cut having mainly from; TO to 20 carbon atoms.

That: middle distillate cut pay be # kerosene cut or a diesel cut.

The present invention involves using a flint purification step for eliminating the nitrogenous compounds contained in the feed followed by two separate oligomerisation steps: -- a first oligomerisation step which makes it possible to essentially react the olefins and which leads to a petrol cut composed of isooiefins having mainiy from 8 to 10 carbon atoms, with an excellent octane number, which can be separated and put to valuable use as such, and * a second oligomerisation step which makes It possible to react the normal olefins with the remaining isooiefins {from the feed) and the Isooiefins formed (unseparated) which will be mainly disposed in the range of olefins with more than 8 carbon atoms.

The prior art in the field of the production of kerosene cuts is fairly wide but reference can be made to EP 1 396 532 describing a process for putting to valuable use a liquid feed of hydrocarbons comprising the following steps: a) separation from said feed of hydrocarbons of a fraction (Qi) essentially comprising compounds containing 5 carbon atoms of which at least 2% by weight is pentenes, b| bringing said fraction (01) Into contact with a hydrocarbons cut (02) compr!sin:| at least in part hydrocarbons having a number of carbon atoms of between 6 and 10 of which 2% by weight is olefins in The presence of at least one catalyst for promoting the dimérisation and alkylation reactions of the species present in the mixture resulting from said contacting operation., and c) separation of the effluents from the step h) into at least two cuts comprising : 119516" L4II7Ä: IT EP2f0246281

··« ® petrol cut (m) whose llgher distiilatfeo point is lower than MChC anil comprising the majority of the unreacted reactaA " a kerosene cut (iß) with a distillation point of between 180¾ and 300¾ comprising the majority of the products from the alkylation and dimérisation reactions»

That patent does not describe any pre-treatméot step, in particuiar for purification of the starting feed (öl). FR 2 887 555 describes a process for the preparation of a diesel cut from a €2 €12 oiefinic cut comprising the following steps; 1} oligomerisation of an oiefinic C2-C12, preferably C3-C7 and more preferably still C3 -C5 hydrocarbons cut, 2) separation of the mixture of products obtained in step I) Into three cuts of which an intermediate cut has a final hoi!in§ point of between 200 and 220°C, and 3} oligomerisation of the Intermediate eat performed In the presence of a cut of C4 aml/or C5 oiefinic hydrocarbons.

That process therefore uses as the feed a very broad- oiefinic cut and implements two separate oilfdmerisatiön operations» It does not refer to the possibility of p re •^treatment of said feed. In particuiar purification in regard; to possible nitrogenous compounds contained in that feed. FR 2 871 167 and FR 2 871. 168 describe processes for the production of gas oil cut from petrol cuts comprising a first step for separation of the normal and isooleflns, the oligomerisation step relatlrii spiiiy the normal olefins.

The process according to the present invention does not necessitate any preliminary separation of the normal and isodieflhs.

Finally the patent application lodged under the Mo 10/03,559 describes a complex process invoiving an oiefinic €4 QÖ cut to which there is added an IPG cut and a BTX cut (abbreviation for benzene, toluene and xylenes) making it possible to perform a reaction for alkylation of the olefins in the BTX cut. US 2007/0213575 describes a process for the production of a distillate cut from an oiefinic C4-C5 feed comprising a step for purification of the feed, one or mere oilidmerisation steps, a separation step and a hydrogenation step.

The process according to the present invention does not require any alkylation step and therefore does not need any cut of type BTX.

Figur® í shows a diagrammatic: view of the process according to the InvihiOh using two separate oligomerisation unis preceded by a step tor petiheahoh of the feed: oyer a capture mass, iiiiir dëctîptm of the invention

The process according to the invention uses two separate oligomerisation units operating on different catalysts and under different operating conditions.

The process according to the invention can he defined as a process for the production of a middle distillate cot having mainly from 12 to 25 carbon atoms from an olefinic feed having mainly between 4 and 6 carbon atoms,, comprising the sequence of steps recited In claim 1.

In the process according to the Invention the starting olefins cut must comprise a minimum of branched chain olefins, referred to as isooieflns, which minimum can be fixedat 10%by weight and pretorahiy 20% by weight., with respect to the whole of the oledhs of the feed.

When extracting a petrol cut it the issue from the first oligomerisation step (OLG!) it Is appropriate nonetheless to maintain a proportion of said petrol cut in the effluents from the; :fri|t0if|pmihiatlon step feeding the second oligomerisation step (OLG2).. That minimum: proportion can be fixed at 10% and priferabiy 20% of said petrol cut,

DETAILED DESCRIPTION OF THE INVENTION

The feed is formed by a cut of olefinic hydrocarbons containing from 3 to 8 carbon atoms, preferably from 4 to 6 carbon atoms. It contains from 20% to 100% of olefins, preferably from 20% to 80% of olefins, and still more preferably from 40% to 60% of oiefins.

If may come from a fluidised bed catalytic cracking unit or a naphtha steam cracking unit or an alcohol déhydration unit or a FischemTropsch synthesis unit or again other sources availabie from refining or petrochemical units.

The description of the process Is set forth with reference to Figure 1.

The feed to be treated (1) is passed into a purification unit (PUR) involving the use of a moiecuiar sieve based on eeolite of faujasite type (for example of typeÄlk or Na¥| operating under the following operating conditions; - temperature of between 2Cf€ and 50°C, “ pressure of 5 to 30 bar% * HSV of between 0,5 andM h*X,

Ah' example Is zeolite U$% fér example^ that marketed by the company Axons under the name SBE Î3X.

That purification uni (PUR) is primarily Intended to eliminate the nitrogenous compounds contained in the feed and which constitute poisons in relation to the cataiysts used in the downstream~disposed oligomerisation units. The effluent (2) from the purification uni (PUR): Is passed Into a first oligomerisation step (OLG!) operating at a temperature of lower than 120°C on a catalyst: of silica-alumina type*

The oligomerisation catalyst fór the first oligomerisation step (OLG:!.) is an amorphous siifeeuiummatrtased catalyst, preferably selected from silica-aluminas and sliicated aluminas and preferably siilcated: aluminas.

The ratio by mass SI02/ÄI203 Is between 0,05 and 10 and preferably between 0,2 and 1, A preferred catalyst Is for example that marketed by the company ÄXENS under the name IP 811,

The effluent (3) from the first oligomerisation step (OLG 1): is passed Into a separation unit (PliTX) for extraction of a petrol cut (S') with a good octane number and which can he returned to the petrol pool (POOL), A part of that petrol (3!) Is directed towards the oligomerisation unit (OLG2),

The effluent (4) from the separation step (DISTT) is passed Into a second oligomerisation step fGL02) operating at a temperature higher than i20°C on a catalyst of zeolite type such as for example a catalyst containing a zeolite ZSM~ S.

The zeoiite-dsased catalyst used In the second oligomerisation step (OLG2) preferably comprises at least ene zeolite selected from the group formed by zeolites of aluminosiilcate type with an overall Si/AI atomic ratio of higher than 10 and with a pore structure of 8., 10 or 12MB,

That zeolite is still more preferably selected from the group formed by the zeolites: ferrierite, chabazite.. zeolites Y and US-Y, ZSM-5, 2SM*12, NU-86, merdenlte, ZSM-22, NU-10, 2BM~30, ZSM-H, ZSM-57, 2SM-35, Í2M-2, ITQ-6 and SAPO, taken alone eras u mixture* %ry preferably said zeolite Is selected from the group formed by the zeolites ferrlerieí líiH-S, mordenlls and 2SM--22 taken alone or as a mixture, ifill mort: preferably the zeolite used is ZSM-S.

The effluents (5) from the second oligomerisation step (OU32) are then separated in a separationsonlf (DIST2) from which at least 4 outs are extracted; «:a head! eut (8), referred to as the raffinate* corresponding to: an tP3 m% - an intermediate cut (?) corresponding to a petrol with a number of carbon atoms between S and 10, « a bottoms cut (8) referred to as a middle distillate with a number Of carbon atoms between IQ and 22 which is passed to the total hydrogenation unit (NT) to constitute the kerosene or gas oil complying with the commercial specifications, and * a so-called residual cut (S3) with an initial boiling point of higher than 28CfC if the final cut being sought Is kerosene or higher than .360°C If the final cut being sought is gas oil, which rejoins the fuel pool of the refinery.

EXAMPLES

Following examples ,1 and 2 do not illustrate the invention.

These two examples are obtained from laboratory experiments, 200 grams of molecular sieve NaX activate# by heating in a how of dry air at 350°€ for 16h are disposed in a first fixed bed for implementing the purification step, 125 grams of eataiyst IP 811 are disposed in a second fixed bed for implementing the first oligomerisation step (OLG1). 75 grams of catalyst IP 811 are disposed in a third fixed bed for implementing the second oligomerisation step (OLG2)

The various beds are arranged in series.

The feed used is a CSAfB cut referred to as light petrol which comes from an FCC unit, under the name LGN (light cut naphtha).

It is composed in percent by mass of: 1,9% of butanes and butenes (0,4 and 1,5% respectively); 25% of iso-pan ten es; 24% of mpentenes; 28% of pentanes; 1.1% of hexenes and 7.0% of hexanes.

The density of the feed is 9,5548,

Il further contains organic nitrogenous; compounds totaling a content of Ii,6 ppm by weight expressed as elementary nitrogen and; IS ppm by weight as elementary sulphur.

It is inie^ed into the first bed (for performing the first purification step) in an upward direction at a rate of 36 g/h, the pressure being maintained at an effective Paine of 50 bars at the ambient temperature.

Analysis of the elementary nitrogen issuing from that purification step shows a value lower than 8,5 ppm by weight, the effluent from the first bed is Integrally passed into the second bed for the first oligomerisation step (OLGi) in which the temperature Is gradually increased between 68¾ and 120^0 in order to keep constant the conversion of the Cf isooiefins at between i0% and 85%, à mean increase of 3¾ every IGOh Is necessary to attain that objective. Under those conditions the conversion of the C5 n-olefins is between 10% and 20%,

The effluent of the second bed is integrally passed Into the third bed for the second oligomerisation step (QLG2) In which the temperature Is gradually Increased between 158¾ and 238¾ In order to keep constant the conversion of the CS olefins at between 25% and 80%, Ä mean Increase Of f%/i00h is necessary to attain that objective.

The effluent from the third step Is separated by distillation into four cuts: - a C4 cut (4% by weight},. - a cut iS%-148%, (44% by weight) constituting the fight petrol cut whose resear dr octane number is 15,5, * a cut 540-280%, (42% by weight) which Is then hydrogenated to provide a kerosene cut Whose characteristics are as follows:

Smoke point, 38 mm; flash point: 45°C; crystallisation point: o65°C; density ; 0.770, Hydrogenafien is effected with a nickel catalyst at 180% under 50 bars of hydrogen with an HSV of 0,5 and a hydrogen flow rata of 50 NL/h and a feed rate of 48 g/h, and - a residue 280-f (18% by weight).

Ixamole 2: G4 feed ex FCC -f C5-C6 f LCIMI

The arrangement of the various hasis corresponding to the three steps for purification, first oligomerisation anti second oligometisati^ is the same as in Example 1,

The catalysts used in the steps OLGi and OLG2 and the capture mass used in the step PUR are the same as lolxampie L

The feed used is a C4 feed from the catalytic cracking unit (FCC) to which there has been added a €5~Ci cut referred to as light petrol which comes from an FCC unit under the name L€I4 (light cut naphtha).

It is injected into the first bed for the purification step (PUR) upwardly at a rate of 36 grams/hour.

Thei;pressureci:scmai:hite|:Ped at an effective pressure of 50 bars at ambient temperature.

Analysis of the elementary nitrogen at the exit from that section shows a value of lower than 0,5 ppm by weight.

The effluent from the first bed is integrally passed into the second bed for the first oligomerisation step (OLGi) in which the temperature is gradually increased between 5(}°C and i'KfC to keep constant the conversion of the CS isooiefins at between 80% and 85%.

Under those conditions the conversion of Isobutene is higher than 95%* Ä mean increase of Äevery iOOh if necessary to attain that objective.

Under those conditions the conversion of the €4 and C5 normal olefins is between 10 and 20%,

The effluent from the second bed is passed Integrally into the third bed for the second oiigomerisation step (OLG2) in which the temperature is gradually increased between ISCfC and 230°C in order to keep constant the conversion of the C5 olefins between -7¾% and 80%.

The cnnversidn of the C4 olefins is higher than 80%, A meahi increase of i°C/100h Is necessary to attain that objective.

The effluent from the third step is separated by distillation Into four cuts; ·· a cut €4-(1655 by weight), - a cut IS'TMdCfC, (42% by weight) constituting the light petrol cut whose research octane number (ROM) Is §5.5, - a cut £4Q8C“28Öc€, (32% by weight) which Is then hydrogenated' (conditions identical to those described in Example 1) to provide a: kerosene cut whose characteristics are as follows:

Smoke point; 38öCp flash point· 48°Q crystaHisatlon point: <-0S°€; density: 0,778., » a residue 280-1- (10% by weight).

Claims (3)

1. Eljárás dízel vagy kerozin részpárlat előállítására főleg 4·· és ö.szénatomos olefin aiapsnyagho!, két óligomorWelós egfsig alkalmazásával Szabadalmi igénypontok X, Eljárás Illeg 10-22 szénatomszámu kizéppérlot elöáliÉására főleg 4-6 szénatomos olefin alapanyagból, amely legalább 10 tÖmeg% elágazó láncú olefineket tartalmaz, amely eljárás magában foglalja a kővetkező lépesek sorozatát: X) az alapanyagbél tisztítási lépése |ΡΧΜ) feujasit típusé zeolit-aiapú molekulaszitán, amely a nitrogén-tartalmú vegy öleteknek az alapanyagból történő eltávolítására szolgád és öőö£2nái alacsonyabb hőmérsékleten működik, 2} a tisztítási lépésből kijövő effiuens első oligornerizáclós lépése ('Öidél), amely X 2D ó€*nál alacsonyabb hőmérsékleten van végrehajtva amorf sziliko-alumlnát típusú amorf katalizátoron, amelyben az SI02/ÄI203 tömegaránya 0,05 és 10 közötti, és előnyösen 0,2 és X közötti, amely első oligomertzácíós lépésből 8-12 szénatomos benzinpárlat van extrahálva, miközben a benzinpárlat minimum 10 %~a van fenntartva az első ollgomerízádős lépés efíluenséhen, S) az első olifömerizáclós lépésből kijövő effiuens második oligomerízáeíés lépése, amely I20°C-nál magasabb hőmérsékleten van végrehajtva zeolit katalizátoron, 4) a misodik ollgomerlzados lépésből kijövő effiuens elválasztási lépése legalább két részpárlatra, maximum 12 szénatomos henzinpáiiatrá és 12-25 szénatomos kizéppárlatra (amit kerozin’· vagy clíxeipárlátnak neveznek), és 5} á középpáriát teljes bldrogénezésl lépése, ami lehetővé teszi a piaci előírásoknak megfeleli kerozin vagy dízel nyerését,
2. 2. Az 1, igénypont szerinti eljárás főleg 10-22 szénatomszámú középpárlat előállítására főleg 4-6 szénatomos olefin alapanyagből, amely legalább 10 tömeg% elágazó láncú olefint tartalmaz, ahol a második oligomerízáeíés: lépés (OLD2) a következők által alkotott csoportból kiválasztott zegil"iiipú katalizátoron van végrehajtva; ferfierlt, ZSH*5> "f m~M>f mordenlt, 2SN-22, NU.40, 2SM~30, ZSN-ll, 15H-S7, ZSM-35, tZM^r 1TQ-6 és IN-5.
3. 3. Az l, igénypont szerinti eljárás főleg íÖ-22 szénatomszámú középpárlat: nllllftisira főleg 4-6 szénatomos olefin alapanyagból,, amely legalább iö tőmeg% elágazó láncú olefint tartalmaz, ahol a második oHgomenzáeios lépés (OLG2) zeolít-aiapu katalizátoron van végrehajtva, és az alkal mazott zen i if 25P ~S,