DE1593597B2 - Process for alkylating an isoparaffin - Google Patents

Description

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out, and the outflowing acid phase, which contains dialkyl sulfate, the alkylation acid catalyst used is treated for the purpose of separating off the dialkyl of about 90% acidity to the absorber 12 sulfate, which in turn is also conveyed through the lines 21, 21 α and 21 b. The schickoing will be directed to the alkylation zone. When the reaction mixture is from absorber 11, the olefin in the absorption zone in liquid phase 5 is passed through line 24 to the settling vessel 23. If the carbon content is dissolved, part of the dialkyl sulphate phase containing unreacted propylene fate dissolves in it and flows with the hydrocarbon absorption and dipropyl sulphate, which in the settling vessel 23 drains separately to the alkylation zone. Advantageously, the absorption zone is cooled by evaporation through the line 25 to the adsorber 12. The acid and hydrocarbon phases are a part of the olefin hydrocarbon feed 10 in the adsorber 12 by rapid circulation by means of the and the resulting olefin-containing gas is brought into contact with the high-speed stirrer 7, which is passed through the to a gas phase absorption stage. When motor 8 is driven. The temperature of Adsoreiner embodiment of the invention, a gas production about 12 is maintained at -1.1 to +4.4 ⁰ C by Ummiger olefin, the olefin is less than the stoichiometrically running the Alkylierungskohlenwasserstoff-Ummetrische set contains, for the purpose of converting the ge - 15 Settlement mixture through lines 16 and 166, the entire sulfuric acid in dialkyl sulfate with the pressure reduction valve 19 and cooling coil 20 in the sulfuric acid catalyst in a first absorption adsorber 12. The outflows of the cooling coils 17 and zone brought into contact, with practically full 20 , containing vapor-liquid mixtures of Al constant removal of the olefin from the absorber end, kylation products, unused reaction part gas is effected. The effluent from the first absorber and diluent are collected in the tion zone containing both monoalkyl sulfates as lines 18a and 186 and through line also dialkyl sulfates, is then passed to a second absorption zone 18 to the usual compression and distillation apparatus, namely in contact with lines listed as product recovery of a stoichiometric excess of olefin on unit 22.

Basis for complete conversion of mono- 25 The conversion mixture of adsorber 12 is

alkyl sulfates and sulfuric acid in dialkyl sulfates. passed through line 27 to settling vessel 14.

According to the invention, the olefin absorption thus takes place The separated hydrocarbon phase from settling in the sulfuric acid used in a stoichiometric vessel 14, containing unreacted propylene and dimetric excess of olefin, with practically the propyl sulfate, is converted through line 28 to alkyl total sulfuric acid to dialkyl sulfates converted into 30 rungsreaktor31, in which which will propylene and di; the unabsorbed olefin reaches the alkyl propyl sulfate as described below with an isobutane enrichment zone. According to one embodiment of the conversion with the formation of alkylate and driving free, the liquid olefin, with which the deposition of 100% sulfuric acid,
Sorption zone is charged, through the exothermic The acid phase from the settling vessel 23 is evaporated by the heat of the olefin absorption and this 35 line 32 is passed to the countercurrent extractor 33 near its steam through a preceding absorption zone upper part. Isobutane is also fed into the. Extractor 33 through line 34a close to the bottom.

In the drawings shows leads. The isobutane passing through the extractor 33

F i g. 1 the invention with two absorbers, which dissolves dipropyl sulfate from the descending acid phase,

work that a countercurrent contact of 40 The spent acid, containing an acid-oil

Olefin and acid, in combination with a complex of alkylation impurities and water

The alkylation unit using a cooler is removed from the extractor 33 through line 36.

ment of the drain; guided. The hydrocarbon head portion (overhead)

F i g. 2 illustrates the use of gaseous from extractor 33 containing an isobutane extract of

Olefin in a first absorption stage and from liquid dipropyl sulfate, is through line 37 to the acid

according to olefin in a second absorption stage with handler 38 performed. A small stream of used

Self-cooling of the second absorption stage. Alkylating acid is also supplied through line 21 c

Referring to Fig. 1, the acid phase is passed to acid handler 38. The Acid Handler38 Settling vessel 14, containing monopropyl sulfate, di- is a mixer with a paddle stirrer 45, propyl sulfate and sulfuric acid via line 13 for 5 ° propulsion by motor 46. The entire Absorber 11 out. The propane-propylene charge polymers oil and the acid-oil complex, which is in the Kung is through line 10 to the absorber 11 in an extract from the extractor 33 can be present through Amount led that a stoichiometric excess removes the acid in the acid treatment 38. The Uman Propylene is created, which becomes all of the monosetting mixture from the acid handler 38 alkylene sulfate and the remaining sulfuric acid in dipropyl 55 passed through line 40 into the settling vessel 41, sulfate converts. The contents of absorber 11 are The acid-treated head portion from the sediment mixed by agitation by means of the high-speed vessel 41, which is practically free of alkylation contaminants 6, which is driven by the motor 5. and contains isobutane and dipropyl sulfate, The temperature of absorber 11 is raised to about -1.1 through lines 42 and 28 to alkylation bis +4.4 C held by the alkylating carbon 60 reactor 31 led.

hydrogen reaction mixture through the lines alkylation reactor 31 is a common touch

16 and 16a as well as the pressure reduction valve 15 device which is connected to the cooling coil 24 and the

is conducted, whereby evaporation of a part of the high-speed stirrer 3 is provided, which is produced by the motor4

Hydrocarbon and cooling the obtained is driven. Fresh olefin charge that

Vapor-liquid mixture is effected. The ab- 65 contain propylene, butylene and butylene polymers

The cooled vapor-liquid mixture is passed through the can, is in line 29, the isobutane feed

Cooling coil 17 conducted in direct heat exchange in line 30 and the circulating iso-

with the reaction participants in absorber 11. butane in line 34 to the alkylation reactor31

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promoted. Circulating acid catalyst from the settling During the adsorption step, as much acid as possible should be used Vessel 39 is placed in the section 21, and a small amount is reacted with an olefin to form dialkyl sulfate fresh sulfuric acid with a strength of 97.5 to be. Propylene is used as the olefin feed 99.5% is preferred to the low loss from the. The absorption can either be in the System of spent acid from the extractor 33, 5 vapor or liquid phase are executed or which has been added through line 43, in a combination thereof. For example, can same - passed to the alkylation reactor 31. That is the main part of the absorption in the vapor phase Isobutane will be carried through the olefins and alkyl sulfals in and subsequently in the liquid Alkylation reactor 31 alkylates to form a phase for the final part of the absorption step High quality alkylates and release of io for the purpose of high conversion of the acid to 100% dialkyl sulfa Sulfuric acid from the alkyl sulfates. th. Advantageously, a concentrated olefin-Das Reaction mixture from reactor 31 is charged in the liquid phase, e.g. B. from the catalytic through the line 44 is passed into the settling vessel 39. see cleavage, fed to a mixing pump, As mentioned above, some of the separated is used to remove the acid phase from the Hydrocarbon phase from the settling vessel 39 is used 15 vapor phase adsorption to the extractor for the purpose of extraction, to pump the absorbers 11 and 12 by indirect traction of dialkyl sulfate. Desired heat exchange to cool or in them a suitable one, all of the unreacted olefin can be separated off te maintain low temperature. Another or forwarded to the extractor and in the isobutane part is used to extract the alkylation reactor 31 and ultimately for the alkylation cool by passing it through lines 16 and 20 zone.

16c, the pressure reduction valve 48 and the cooling used alkylating acid with a titratable snake 47 heads. The liquid and vapor from acidity of 88 to 93 weight percent is the front Cooling coil 47 containing propane, isobutane and added acid feed material for the Absorp alkylate, is withdrawn through line 18c and step, although in some cases, e.g. with the same mixture in lines 18σ and 25 amylenes are to be alkylated, they have a lower value 186 combines for recovery and distillation can have a concentration of 80 to 85%. Acid off itider product recovery plant 22. In other sources, such as B. fresh acid or acid Layer 22 are common compression and distillation chemical reactions and from acid treatment tion systems used to separate the alkylate from petroleum naphtha or lubricating oil, can also be used which is discharged via line 49, the ISO 30 are turned.

butane, which is recirculated via line 34. If strong acid is used together with Pro, and the propane, which is discharged via line 50, has a temperature of -6.67 to + 15.56 ° C will. satisfactory. If butylenes are used, the above in connection with FIG. 1 described - in particular containing isobutylene or isobutylene In the process, a fresh olefin feed 35 feed materials are fairly low temperatures conveyed to the absorber 11, and temperatures and short times are advantageous. Isobutylene can Ziig that unreacted olefin from the absorber 11 is first advantageously removed by tin Absorber 12 is performed, to which the use of a weak acid of about 60 to turned alkylating acid is passed. This current 70% concentralization.

causes countercurrent contact so- 40 Relatively concentrated olefinic material, e.g. B. probably of the olefin as well as the acid and leads to one from the catalylic cleavage, is preferred, maximum olefin adsorption, since the weaker oil is converted with the stronger acid, although from an economic point of view, lean fin stream. Starting materials, such as lean propylene material, but fresh olefin can also be beneficial in the absorber with little value as a fuel. λ 12 through an olefin feed line (not shown). The absorption step can be carried out in from the technology γ device. In this case, the coal-known contact devices are carried out hydrogen-top portion of the settling vessel 23 in the line, z. B. in mixer settling vessels, centrifugal Be-25, containing isobutane and dialkyl sulfate, from the absorption rührungsvorrichtungen, countercurrent towers, or diverted over 12 and two or more mechanically stirred reactors, the 31 led directly into the alkylation reactor. By supplying the isobutane and di- 50 working with generation of a countercurrent flow, alkyl sulfate from the settling vessel 23 directly to the alky- The contacting in countercurrent is gated and not to the absorber 12 it is possible, preferred, in order to achieve a high conversion of acid ' That a greater percentage of acid is obtained in extractable alkyl sulfate and, in most cases, dialkyl sulfate is converted with a high conversion of the olefin,
lower total acid consumption in the alkylation 55 If the absorbers work in the liquid phase, and also with lower olefin loss than alkyl sulfates, the unreacted hydrocarbon dissolves a significant proportion of the dialkyl sulfate in the acid consumed from extractor 33, e.g. B. about 20% of this olefin to both absorption zones by weight at about -1.1 ° C in propane-propylene. It is carried out under such conditions that practically it is desirable to supply the dipropyl sulfate of the alkyd all of the olefin in the hydrocarbon phase of 60 lation, and yet this is undesirable, one of the touch devices is absorbed if too much propane or η-butane is present, because such can it may be desirable for this portion of the separated diluents to adversely affect the alkylation reaction of the hydrocarbon phase from the alkylation system. Such diluents can de-deflect, and indeed because of the present distance, and at the same time provide cooling for the diluent hydrocarbons. In this case, 65 absorber by letting down the settling vessel on it is advantageous to remove the dissolved dialkyl sulfate from the Koh- head and pass the resulting cooled lenwasserstoff z. B. to gain by evaporation liquid-vapor mixture in indirect heat and supply it to the alkylation. exchange with the absorber. After using

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for cooling, the resulting liquid-vapor guidance good separation of the acid and hydrochloric water mixture is separated off, and the substance phases containing dialkyl sulfate in the settling vessel 23 facilitate this separation-liquid, which in terms of propane or ßutantern are tert by introducing isobutane into the hold has been significantly reduced, then absorption mixture is fed to the alkylation by means of a not shown here. 5 Precautions. For example, isobutane can be used in the dia j It is desirable to introduce practically all of the dialkyl sulphon line 24 which extends from the absorber to the waste in the acid phase from the absorber to the maxi-setting vessel. Advantageously, one can get a painful yield of recovered acid in extra amount up to the full amount that would normally be here. Extraction temperatures are charged below the extraction stage, up to 6 vol. B. ₁₀ parts of dialkyl for each volume or more, or about 4.44 to 15.56 ^J C and short periods of less than 5 volumes per volume of the acid phase to than about 20 min. Are preferred. The extraction mixing the absorber reaction gel. i , cn feed, step can be done in devices known from the art, so that the main part of dialkyl sulphate is extracted, for example in mixer settling vessels, centrifugal loading takes place and a good separation takes place. If this is agitating devices or countercurrent towers, e.g. B. _{15 is} schehen, the hydrocarbon phase is carried out from Abin a disc contact extractor set vessel 23 passed for alkylation, and it remains. less dialkyl sulfate in the acid phase that in the

Isobutane is preferably used for the extraction → the usual extraction stage is to be extracted. as

tion of the dialkyl sulfates from the absorber conversion result can be an extraclion tower of small-

mixed, but normal paraffins such as ₂₀ ren dimensions can also be used.

Propane and η-butane, or olefins can be used. The solubility of dialkyl sulfates in isobutane increases, dialkyl sulfals have a greater relative solubility with temperature. Thus, in general, a higher solvent alkyl acid sulfate is used in hydrocarbon solvents than the lower temperatures. So it is desirable that effective d jsization is needed. To use the equilibrium between alkyl conditions in the extraction stage, so ₂₅ sulfate and the desired dialkyl sulfate, that one not only extracts the dialkyl sulfates, but also the more favored at lower temperatures, and with alkyl acid sulfates. Such conditions also result in less degradation of the acidic material, a high dose of solvent in the ri Is instead. It is seen from these factors advantages order of 6 moles of solvent per mole of zi, -nen, in order to achieve superior results, namely, alkyl sulfate or higher, Raffinate-circulation-loop, ₃₀ ei <e higher yield of extracted dialkyl multi-stage counter-current extraction and optimum Ba m c less solvent. This can be done at the rate of delivery for a given extiac using an inverted temperature vessel. In batches with test facilities wur- tu gradient, a higher temperature that is in the much better results with a ratio of output stages of a multi-stage countercurrent extraction the hydrocarbon solvent containing the GR ₃₅ ο Jer at the bottom of the tower than in the initial stage sentlichen isobutane to Dipropyl sulfate from about 6 heights or in the top of the tower. Relatively warm aims than with a ratio of 3 and slightly better isobutane is fed into the final stage or near the bottom results with a ratio of 16 than with one; s tower so far that mihde,> ttns3 Vo ratio of 6. Under The working conditions are that Iu .iina isobutane per volume of dialkyl sulfate is present, volume ratio of isobutane to dipropyl _{sulfate 4t} > de a temperature of about 15.6 ° C in the tower base about the same as the molar ratio. For dibutyl- yielded. At an earlier stage or on the sulphate, for example, the molar ratio is somewhat higher than the volume half way up the tower that of dibutyl sulfate is 210. The approximately -6.7 to - 1.1 ⁰ C is introduced so that the l'empegenaue required solvent dosage depends in 45 temperature in the upper part of the tower about 7.2 to 10.0 ° C begewissem extent of the other conditions. wearing.

For example, the solubility of dialkyl sulfates increases if the extraction is carried out in the case of extract discharge

with the temperature and a column of given waste temperatures of about 7.2 to 37.8 ° C,

measurements, e.g. B. a rotating extraction tower can remove a large percentage of the dialkyl sulfates from the

Disk, has an optimal throughput. There seems to be 50 solution taken out by cooling

however, that the volume ratio of isobutane to extract to a temperature below about 4.4 ° C,

Dialkyl sulfate always above 3 and preferably or preferably below about - I ₅ I ⁰ C. The so removed

should be above 6. separated dialkyl sulfate is very pure and free from alkyl

The raffinate or the spent acid from the impurities. Hence, it is a preferred extraction stage which contains water, alkyl acid sulfates, 55 feedstock for the alkylation. The ab dialkyl sulfate and the reaction product of acid cooling can be carried out in various ways, and polymeric oil that is formed during the alkylation z. B. formed by evaporation of part of the hydrocarbon absorption and acid treatment steps material or by indirect heat exchange with the has. The extract contains the hydrocarbon-solvent-coolant-circulating isobutane, which is about -6.7 ° C, dialkyl sulfate and a relatively high temperature. This cooling operation can also use a small amount of alkyl acid sulfate. The extraction conditions are applied to the hydrocarbon phase and are usually chosen so that they can be used as an absorber, e.g. B. the head portion from the settlements, if only the acid-oil reaction vessels 14 and 23 are present, especially if the settling product and water in the used acid vessels are operated at about 4.4 ° C or higher, or come close to the acid phase , with all alkyl sulfates 65 The unreacted propane-propylene in the settling vessel is in the extract or in the organic phase. even more above -1.1 ⁰ C. Approximately 50 ",, of

If this problem arises, dipropyl sulfate can be removed from the solution.

will come by cooling the separated Kohlenwasserst off phase to about -6.7 ⁰ C.

The polymeric oil contaminant in the absorber-extractor extract is highly unsaturated and easily reacts with strong sulfuric acid, e.g. B. with freshly prepared for the alkylation acid or with used alkylating acid of about 90% concentration. The strong sulfuric acid also removes all of the acid-oil complex present. Thus, if desired, the absorbent extract can be acid treated prior to being fed to the alkylation and optionally after removing any excess unreacted olefin. Good results are obtained by acid treatment of the polymeric oil in isobutane solution with used alkylating acid of about 90% concentration at a temperature of 29.4 ° C. and for a period of 1 hour. However, a temperature not higher than 4.4 to 15.6 ^C C and a short time on the order of a few minutes or less is preferred. In fact, such a short time seems to be sufficient, which results from mixing by means of a pressure relief port.

In general the conditions are for the alkylation step those known in the art. However, the bulk of the recycled acid is called alkyl sulfates passed from the recovery section to the alkylation, and only a minor proportion of the acid is supplied as a freshly made acid with the usual 98 to 99.5% concentration. As the alkyl sulfates are essentially anhydrous, the system catalyst has a tendency when using the acid recovery process uses to have a lower water content and is generally superior Quality because an alkylate of lower final boiling point and higher octane number is obtained. Of course Less drying of the feed materials can be used if desired, but in such a case the water content of the system catalyst can be as high as the usual one Operation without acid recovery. Usually the water content of the system catalyst is without Acid recovery above 2.5 weight percent or in the range of about 2.5 to 4.5% when fresh gives up acid of 97.5 to 99.5% concentration. Under the same conditions - under Using the present recovery process - the water content is usually below about 2.5% in the range of about 1.0 to 2.5%. The sulfuric acid in the alkylation system is common kept within a range of about 88 to 95% by purifying the acid consumed by the system will. In a system having a plurality of reactors, it is preferred that the acid be the lowest Concentration purified and fed to the acid recovery system.

A large excess of isobutane is used, e.g. B. from 60 to 80 percent by volume of the hydrocarbons in the alkylation reaction mixture. As a result, a large amount of isobutane must be recovered and reused be circulated in the alkylation process. It is also used for the recovery process described available.

In addition to the olefin, which is fed to the alkylation stage in the form of alkyl sulfates, is usually additional fresh olefin fed to the alkylation stage. For example, if propylene and / or Butylenes, but especially propylene, are used for the absorption stage, it is advantageous to use butylenes also to be used in the alkylation stage. If the total acid consumption is reduced, so will the Amount of olefin required for reaction in the acid recovery section, decreased, and is usually in the range of 10 to 25 percent based on the total olefin, although it can be even less can.

example 1

^r

In the following example, the feed materials used in Table I are in one array according to FIG. 1 used.

Table 1

Ethane

Propylene ..
Propane ...
Isobutane.
η-butane ...
Isobutylene
Butylene-1.
Butylene-2.
Penlan

Propane- Butane- 0.4 0.1 Isobutane Propylene Butylene 62.3 2.7 in percent by weight 33.7 34.6 3.6 11.0 15.9 6.9 9.5 91.1 22.9 2.0 3.0

100.0 I 100.0 I 100.0

10 ml of alkylating acid used per minute from the settling vessel 39 with a titer of 91.0% were fed into the absorber 12 at about -3.9 ° C. Fresh propane-propylene feed at a rate of 45.0 ml per minute was added to absorber 11 at about -1.1 ° C. Unconverted propane-propylene from absorber 11, which was separated off in the settling vessel 23, was fed to the absorber 12. The hydrocarbon phase or the unreacted propane-propylene from absorber 12, separated in the settling vessel 14, contained 11.8% dipropyl sulfate. The acid phase from absorber 11, separated in settler 23 and containing 80.6% dipropyl sulfate and 15.3% monopropyl sulfate, was passed at a rate of 24.2 ml per minute to a rotating disk extraction tower near the top . 315 ml per minute of the isobutane feed was fed to the rotating disk extraction tower near its bottom. It was maintained, a temperature gradient in the extractor, wherein the bottom temperature of about 12.8 ⁰ C and the top temperature was about 18.3 ° C. The head portion from the extractor containing 83.8% isobutane, 5.7% and 0.3% dipropyl Monopropylsulfat, was a mechanically ml stirred reactor of 600 ml at about 26.7 ⁰ C together with 0.2 per min. Of used alkylating acid supplied from 91.0% concentration. The acid treated product was sent to a settler where a hydrocarbon phase containing 84.2% isobutane, 5.8% dipropyl sulfate and 0.1% monopropyl sulfate was separated at a rate of 341.2 ml per minute.

105.5 ml per minute of the butane-butylene feed in line 29, 315.4 ml per minute of the isobutane feed in line 30 and 0.181 kg per hour. 97.5% sulfuric acid in line34 were together with

11 12

brought the hydrocarbon phases from the settling vessels 110 into contact with the acid phase in a

14 and 41, the circulating acid in line 21 and the first subdivision, which is

Circulating isobutane is formed in line 34 in a Stratco-alkyl. The acid and hydrocarbon phase

tion reactor supplied, which are agitated with effective Ver by the mixer 161 , the through

mixing was maintained at 4.4 to 7.2 ° C. The reac- 5 motor 162 is driven. The absorption temperature

tion mixture was continuously fed to a sedimentation door is maintained by self-cooling; H.

vessel headed. by evaporation of part of the hydrocarbon

The hydrocarbon phase with a charge from the reaction mixture. The ver

speed of 749 ml per min. was produced, hydrocarbon evaporated from the reaction

was made alkaline and washed with water. 10 partition is withdrawn through line 125

as well as stabilized, to the main amount of butane and and returned to the first absorber 112 . The at

to remove lighter hydrocarbons, with 163 overflowing hydrocarbon-acid phase

about 189 1 per day of the desired alkylate product melts in a central subdivision of the absorber

were manufactured. bers 111, which are located between overflows 163 and 164

Spent acid from the acid handler has been sorted 15, and separates in it into an acid phase, made at a rate of 1.3 ml per withdrawn through line 132 and into one Min. This corresponds to an acid consumption of hydrocarbon phase, which leads to overflow 164 0.081 kg per 3.75 liters of alkylate. A corresponding end subdivision overflows. The hydrocarbon roll test without acid recovery, a phase resulted in unreacted olefin and dissolved alkyl acid consumption of 0.39 kg per 3.79 liters of alkylate. Containing about 20 sulfates is withdrawn through line 128. 90% of the alkylating acid used was converted into di- The acid phase in line 132 becomes alkyl sulpropyl sulphate converted, and about 90% of the formed far separation plant 133 transferred to where the dissolved th Dipropylsulfates were back for alkylation- alkyl sulfates are separated from the acid, z. B. led, in which the sulfuric acid was regenerated. by extraction with isobutane from line 134a. A total of 80% of the alkylation products used were added to the acid in line 142 recovered. together with the hydrocarbon phase in the line

The used acid from the acid treatment 128 is converted through line 134 with isobutane

an analysis of approximately 2.5% water, 10% acid alkylation zone 131 was reported . The from the alkyl sulfate

Polymer Oil Complex, 10% Dipropyl Sulphate and 77.5% Separation Plant 133 Unloading Acid Phase

Monopropyl sulfate. ' ^r 30 withdrawn through line 136.

The test octane value of the total alkoxide. An isobutane-olefin feed in line

from the acid recovery attempt was pure 129 is combined with the isobutane in the line

95.5 and 107.0 with 3.0 ml tetraethyl lead. The streams containing engine 134 and alkyl sulfates from the

octane value was pure 92.6 and 106.8 with 3.0 ml lead tetra lines 128 and 142 and to the alkylation vessel

ethyl. The alkylate from the control experiment carried out without 35 131 . Circulating acid in line 121 and

Acid recovery had an investigation octane-prepared acid in line 143 to be in the alky-

value of 94.7 pure and 105.9 with 3.0 ml lead tracer touch device 131 introduced. the

ethyl. Alkylation touch device 131 is a conventional

With reference to FIG. 2, a lean olefinic container in which the contents with the stirrer 103, feed gas, e.g. B. an absorber tail gas, through which 40 is driven by the motor 104, line 155 is intimately mixed together with the absorber exhaust steam, and the heat of conversion is removed by the gas from the line 125 to the first absorber 112 ge coolant, which leads into the cooling coil 147 . Absorber 112, a countercurrent-touch is introduced through line 116c and the line tower for contacting vapor and liquid-118 c is discharged. Liquid react in the alkylation zone. In absorber 112 , the flowing gas is used in 45 to form the alkyl sulfates and the olefin with isobutane in countercurrent with the sulfuric acid-alkyl formation of the alkylate. The product mixture obtained is brought into contact with the catalyst, which is drawn off through line 144 to separator 139 , top of absorber 112 through line 121 σ, where the hydrocarbon phase is carried by the sulfur. The absorber 112 is equipped with an acid catalyst that is separated off. The sulfuric acid in the middle arranged separator bottom 156 to the 5 ° catalyst is separated by the line 121 in circulation, separation of the downward flowing liquid, which is returned and the separated hydrocarbon withdrawn via line 157 and withdrawn in the intercooler phase via line 116 and cooled to the distil-120 before it transferred to absorber 112 via ion gas treatment plant 122. Is returned in line 158. Coolant for plant 122 is separated propane and through line intercooler 120 is discharged through line 1166 55 and 150 is discharged and the butanes and product are supplied and the coolant effluent is withdrawn separately through line 149 through line 1180. The absorber 112 is working charging. The separated isobutane is passed through the glue with an excess of acid so that essentially a device 134 is withdrawn to recirculate it for complete withdrawal of olefin from the alkylation contact 131 feed gas. Take away the remaining waste,
gas withdrawn through line 160 is
practically free of olefins and can be discharged for fuel purposes. The acid, the monoalkyl- Example 2
and dialkyl sulfates in solution, collects on
Bottom of absorber 112 and is through line 65
113 withdrawn and led to the second absorber 111 . In the following example, the values listed in Table II

In the second absorber 111 , a liquid loading material is shown in the plant

Charge stream rich in olefin through the line according to FIG. 2 applied.

Table II
Mole percent

Gas off Propylene Butylene Isobutane Cleavage Loading Loading Loading system kung kung kung Do not condense sable Components 17.0 Hydrogen .. 21.0 methane 28.0 Ethylene 60 0.5 Ethane 11 5 1 0 Propylene 8.5 51.0 0.1 Propane ...... 63 43 9 2.7 Isobutane Vj-.
0.8 1.9 34.6 6.9 Butylenes 0.4 1.3 48.3 91.1 η-butane 0.4 0.4 11.0 2.0 C5 + 0.1 • All in all ... 100.0 100.0 100.0 100.0

Gas from a cracking plant in an amount corresponding to 44.4 m ³ per day of propylene in line 155 and absorber exhaust gas in line 125, containing an equivalent of 6.8 m ^{3 of} propylene, are at a pressure of about 0.35 kg / cm ^{3 led} to the bottom of the tower 112 . The alkylation catalyst used is introduced through line 121 " near the top of tower 112 at a rate of 43.55 kg per day with a titratable acidity of 90.0% and at a temperature of -1.1 ° C. When the acid flows down through tower 112 , lead! the heat of reaction with the olefin causes a temperature rise. The heat is discharged from the tower in an intercooler 120 by withdrawing a stream downwardly flowing liquid from the Abscheiderboden 156 through line 157 to the radiator 120 and returning the liquid to the entire tower 112 through line 158 C. at about -1.1 ⁰ Practically Propylene and butylene are reacted and retained by the acid, converting 75% of the sulfuric acid to monopropyl sulfate and dipropyl sulfate. Virtually all of the unsaturated hydrocarbons, non-condensables, hydrogen and ethylene are removed from the top of the tower as exhaust gas through line 160 .

The acid phase from the bottom of the absorber 112 is fed to the absorber 111 , which operates in the liquid phase with mechanical stirring under a pressure of 1.05 kg / cm ² and a temperature of 4.4 ° C. The propylene feed shown in Table II is fed to absorber 111 ^{at 46.6 m 3} per day. This feed contains about a 40% excess of olefin based on the original acid to convert all of the sulfuric acid and monopropyl sulfate therein to dipropyl sulfate. By maintaining the pressure of the absorber III at 1.05 kg / cm ² , a portion of the hydrocarbon feed is evaporated while absorbing the exothermic heat of reaction, while maintaining a temperature of about 4.4 ° C. A gas containing about 6.8 m ³ per day equivalent liquid propylene, is developed from the absorber and fed back in circulation to absorber 1 12th The liquid absorption mixture is separated into acid and hydrocarbon phases, each of which contains dissolved dipropyl sulfate.

The acid phase from the second absorber 111, containing about 85 percent by weight dipropyl sulfate, is extracted by countercurrent contact in the liquid phase with 6 parts by volume of the isobutane feed. The dialkyl sulfal extract obtained is separated from a raffinate which contains most of the alkylation impurities contained in the spent alkylation acid catalyst that was fed to the absorption system, as well as all acid-soluble substances that have formed in the two absorbers.

The isobutane extract from absorber 111, corresponding to 580 m ³ per day of the butylene feed shown in Table II, an excess of isobutane feed, 435.5 kg per day of fresh 99.5% sulfuric and circulating acid catalyst are fed to alkylation zone 131 . The reaction products are separated by customary measures with the formation of 595 m ³ per day of the debutanized alkylate. The alkylate product has a pure test octane value of 96.0 and 108.0 with 3.0 ml tetraethyl lead and a motor octane value of 93.0 pure and 107.0 with 3.0 ml tetraethyl lead. The acid consumption is 0.0208 kg per 3.7851 alkylate compared to a consumption rate of about 0.217 kg per 3.7851 that would be expected with normal alkylation. Furthermore, 89.4 m ^{3 of} the product alkylate come from cracked gas which cannot be generated with the usual alkylation devices, which means that gas streams of such a low olefin content, containing non-condensable hydrocarbons and other gases, are unsuitable for direct charging for the alkylation.

For this purpose 2 sheets of drawings

Claims (2)

1 2 procedure is a drastic measure and claims: expensive. The alkylating acid used from the alkylation of isobutane with olefins has one 1. Process for alkylating an isoparafin has titratable acidity of about 90% and is common to many with an olefin in the presence of a sulfuric acid- 5 purposes are still well suited, except, however catalyst made from alkyl sulfates and sulfur - your use as an alkylating acid, which is of interest here the effectiveness of the sulfur catalyst. Acid catalyst through contact bringing about the object of the invention was to provide a at least to develop part of the sulfuric acid catalyst with drive for the alkylation of isoparaffins, an olefin with the formation of alkyl sulfates such as in which by a special combination of steps which is produced, with separation of the formed an advantageous recovery of the sulfuric acid Reached alkyl sulfates from the alkylation impurities catalyst and this in an integrated manner and recycling to the alkylation zone, with the alkylation of isoparaffins with olefins characterized in that the separated using the sulfuric acid catalyst Sulfuric acid catalyst is bound in a 15. For economic reasons it is an emergency absorption zone contacts with an olefinic carbon, at least 80%, preferably a still hydrogen feed, the higher percentage of alkylation used more Olefin contains, as to the complete conversion acid, which is available for the recovery, Development of sulfuric acid to dialkyl sulfate required to recover. It was therefore the aim of the invention is, from the absorption zone also a hydrocarbon, a high recovery of the acid in the form substance phase, consisting of unreacted olefin of dialkyl sulfates to be achieved under practically full and dialkyl sulfate, as well as an acid phase from permanent utilization of the olefin feed. I. alkyl sulfates, monoalkyl sulfates and alkylation - the subject of the invention is a process for alkylation, removes impurities, at least part of the ren of an isoparaffin with an olefin in the presence of ¹ H), hydrocarbon phase in the alkylation zone 25 of a sulfuric acid catalyst, which recirculates from alkyl sulfates, the dialkyl sulfates from the acid phase and sulfuric acid, the effectiveness of the! separated by extraction and at least one sulfuric acid catalyst by contacting \ part thereof leads to the alkylation zone. at least part of the sulfuric acid catalyst 2. The method according to claim 1, characterized as characterized with an olefin with the formation of alkyl sulfates, that the separation of the effluent from 30 is made, with separation of the formed the absorption zone into a hydrocarbon alkyl sulfals from the alkylation impurities and an acid phase by adding paraffin and recycling to the alkylation zone, which is the same Hydrocarbons facilitated. is characterized by the fact that the separated Sulfuric acid catalyst in an absorption zone with 35 of an olefinic hydrocarbon feed to Brings contact that contains more olefin than to completely convert the sulfuric acid to dialkyl sulfate is required from the absorption zone one The invention relates to a process for alkylating hydrocarbon phase consisting of non-mixed Isoparaffin with an olefin in the presence of a 40 set olefin and dialkyl sulfate, as well as an acid ' Sulfuric acid catalyst, which consists of alkyl sulfates and phase from dialkyl sulfates, monoalkyl sulfates and Al-sulfuric acid consists, with the effectiveness of the kylation impurities subtracting, at least one Sulfuric acid catalyst by contacting part of the hydrocarbon phase in the alkylation at least Part of the sulfuric acid catalyst zone recirculates the dialkyl sulfates from the acid ~ with an olefin to form alkyl sulfates such as 45 phase separated by extraction and at least one (j which is produced leads to the alkylation zone with separation of the part formed therefrom. Alkyl sulfates from the alkylation impurities It is well known that acid catalysts can be used in the! and recycling to the alkylation zone. Recover and in situ alkylation reaction zone There are numerous sulfuric acid alkylation regenerate by absorption or conversion of a plants for the production of motor fuels of high 50 olefins with the sulfuric acid catalyst below BiI quality, by means of the reaction of isobutane with the formation of dialkyl sulfates, separation of the dialkyl sulfate olefins Use of a sulfuric acid catalyst, ζ. B. by means of extraction with isobutane, and Alkysators These systems work with the formation of isobutane with the dialkyl sulfates rather high acid catalyst consumption in the use of a sulfuric acid catalyst. In which The order of magnitude of 0.181 to 0.454 kg of acid per 55 alkylation step is practically 100% pure 3.79 1 alkylate and more. The used catalyst regenerates sulfuric acid or from the dialkyl sulfates Somehow they have to be recovered from these facilities. Consider the effect of this measure, It is often used as a source of sulfur in the acid - it means that less of the freshly made acid supplier returned. In any case, the Ge must be introduced into the alkylation zone The total cost of the acid catalyst is an alkyl acid consumption and the overall cost is substantial system decisive for the cost of the alkylate to be reduced. According to the invention, the issue is created. In spite of a corresponding need, it has a separated sulfuric acid catalyst in an absorbent point the recovery of the acid catalytic zone with an olefinic hydrocarbon, tors for a long time no fundamental improvements like propylene, given in stoichiometric excess, In general, the consumed alkyl is brought to 65 stirring with complete conversion of the lating acid worked up by burning to convert sulfuric acid into dialkyl sulfate. The outflowing, uncompromising sulfur as sulfur dioxide and ultimately as a sulfur-containing olefin hydrocarbon phase recover acidic acid. This recovery is used as an olefin feed to the alkylation zone