RU2168490C1 - Method of preparing high-octane gasoline additives - Google Patents

Abstract

FIELD: gasoline production. SUBSTANCE: isobutene-containing hydrocarbon mixture(s) and ethanol are brought into contact with acidic ionite catalyst(s) in two or several straight-flow reaction zones and unreacted C4-hydrocarbons are separated in rectification zone. At last one of reaction zones is followed by rectification zone and at least one of reaction zones is connected with rectification zone so that the latter receives side stream tapped off at point above that where reaction mixture from precedent reaction zone is fed and, possibly, additional amount of ethanol. Reaction mixture from that rectification zone is returned into rectification zone below the side stream withdrawal point. Total amount of ethanol is superior to summary molar amount of isobutene in initial hydrocarbon mixture and ethanol in distilled off stream of unreacted hydrocarbons. High-octane mixture containing 50 to 97 wt % of ethyl tert-butyl ether and 3 to 50 wt % of ethanol. EFFECT: decreased formation of by-products resulting in reduced activity of catalyst. 3 cl, 2 dwg, 6 ex

Description

 The invention relates to the field of production of high-octane gasoline components.

 More specifically, the invention relates to the field of production of high octane mixtures; containing ethyl tert-butyl ether (ETBE).

 The known method [Pat. RU N 1815954, Bull. fig. N 14, 05/20/95) obtaining alkyl tert-alkyl esters, in particular ETBE, by reacting alcohol with isoalkene (s) contained in a hydrocarbon mixture in the presence of an acidic ionic catalyst in a reaction-distillation unit including a reaction apparatus and external ( external) reaction zones filled with catalyst, into each of which feed alcohol and feed isoalkene and / or a stream containing predominantly unreacted hydrocarbons, taken from a 15-60 theoretical plate in the vapor or liquid phase, and the floor are fed ennuyu a remote area, the reaction mixture was fed into the apparatus at 3-10 trays below the sampling point.

 As an option in the said patent, it is recommended that the initial hydrocarbon mixture and a part of the alcohol be fed first to a direct-flow reactor, and then the reaction mixture and another part of the alcohol should be fed into a reaction-distillation unit with external reaction zones.

 The specified method is effective in obtaining methyl tert-butyl ether (MTBE) from methanol and isobutene-containing mixtures. However, in relation to the production of ETBE, the method has significant drawbacks, mainly due to the fact that the reaction of ethanol with tert-alkene reactions (in contrast to the interaction of methanol) has an unfavorable chemical equilibrium (lower equilibrium conversion of isobutene and ethanol), as well as a lower relative the adsorption of ethanol by sulfoionite catalysts (compared with methanol), which requires a high concentration of ethanol in the reaction mixture to suppress undesired oligomerization of isobutene, leading to a decrease in the activity of the catalyst.

 The method practically does not allow, upon receipt of ETBE, to use a combination of the initial once-through reactor and the subsequent reaction-distillation unit with remote zones, since the amount of alcohol supplied has to be distributed between the initial once-through reactor and the remote zone (s) of the reaction-distillation unit and in the initial once-through reactor and / or remote zone (s) the ethanol concentration is insufficient to suppress isobutene oligomerization, as well as achieve high conversion of reagents.

 The high efficiency of high-octane additives of mixtures of ETBE and ethanol has been established, which allows us to propose a method that reduces the above disadvantages.

We propose a method for producing high-octane gasoline additives by contacting isobutene-containing hydrocarbon mixtures and ethanol with acidic (s) ionite (s) catalyst (s) in two or more direct-flow reaction zones and separating unreacted C ₄ hydrocarbons in the distillation zone from these reaction zones as at least one precedes the distillation zone and at least one is connected to the distillation zone as an additional reaction zone, into which a side stream is discharged above the feed of the reaction the mass of the preceding reaction zone, and possibly an additional amount of ethanol, and from which the reaction mixture is returned to the distillation zone below the side sampling point, namely, the total molar amount of the starting and possibly recovered ethanol exceeding the total molar is fed into the process the amount of isobutene in the initial hydrocarbon mixture and ethanol in the stripping stream of unreacted hydrocarbons, and a high-octane mixture with a relative content of iem ethyl tert-butyl ether from 50 to 97 wt.% ethanol and from 3 to 50 wt.% of ethanol based on their sum.

 As one of the options, a method is proposed in which ethanol is fed into the first reaction zone in an amount that provides at the entrance to it an ethanol: isobutene molar ratio of at least 0.8: 1, preferably at least 1: 1, and in an additional ( s) the reaction (s) zone (s) - in an amount providing a molar ratio of ethanol: isobutene at the inlet of at least 1.5: 1, preferably more than 2: 1.

Alternatively, a method is proposed that consists in supplying C ₅ hydrocarbons, including tert-pentenes, and, possibly, hydrocarbons with, as a raw material in the isobutene-containing hydrocarbon mixture or in addition to it, in the reaction zone (s) a large number of carbon atoms and from the bottom of the distillation zone remove a product containing ethyl tert-butyl ether, ethyl tert-pentyl ether, ethanol and C ₅ + hydrocarbons
As direct-flow zones, various types of reactors can be used with different methods of removing reaction heat: adiabatic (at a low concentration of at least one of the reactants), with heat removal through the walls of the tubes, by intermediate cooling of the reaction mass, by recycling to the reactor (s) part cooled reaction mass, by partial evaporation of the reaction mass in the reactor and, possibly, condensation of the evaporated part and recirculation of the condensate into the reactor.

 Application of the method is illustrated in FIG. 1 and 2 and examples. The drawings and examples do not exhaust all possible technological options and other technical solutions are possible while observing the essence of the invention set forth in the claims.

According to FIG. 1, the initial isobutene-containing hydrocarbon mixture F is fed through line 1 and sent completely or mainly to the direct-flow reactor R-1. In P-1, a stream F '(line 1a) may also be supplied containing C ₅ hydrocarbons and possibly hydrocarbons with a large number of carbon atoms.

 The initial ethanol-containing (E) stream 2 is divided into two parts, one of which is sent to P-1 through line 2a and the other to P-2 direct-flow reactor connected via line 2b to the K-1 distillation column as a “side” reaction zone .

 The reaction mixture from P-1, output via line 3, is sent via line 3a to the distillation column K-1. As a possible option, part of stream 3 (stream 3b) is cooled and returned to the inlet to P-1 (shown by a dotted line), and / or, as another possible option, part of the reaction mixture is evaporated in P-1 and at least a part of the outgoing steam stream is condensed and return to the entrance of R-1.

 Above the feed stream 3 from the distillation column output stream 4, which is fed to P-2.

 The reaction mixture from P-2 is returned by stream 5 to K-1 below the outlet point of stream 4.

As a distillate, stream 6 is removed from K-1, containing predominantly unreacted hydrocarbons and an admixture of ethanol, which, if necessary, can be further removed or recovered by any known method (using a water master, sorption by zeolites, etc.)
Bottom K-1 output stream 7 target product containing mainly a mixture of ETBE and ethanol, or a mixture of them with hydrocarbons C ₅ +
According to FIG. 2, in contrast to FIG. 1, rectification in column 1 is preceded by two consecutive once-through zones (reactors P-1 and P-2), at least the first of which is equipped with a system for removing reaction heat (the dotted line shows a variant of removing reaction heat by cooling and recycling to the inlet to P- 1 part of the resulting reaction mass stream 3b). The reaction mass (with the exception of the stream recycled to the reactor, if one is used) by stream 3a enters the reaction column P-2, from where the reaction mass by stream 4 enters the distillation column K-1.

 Above the input of stream 4, a side stream 5 is withdrawn from column K-1, which is sent to reactor P-3. The reaction mixture from P-3 is returned by stream 6 to K-1 below the outlet point of stream 5.

Top K-1 output stream 7 containing predominantly unreacted hydrocarbons C ₄ . Bottom K-1 display a product containing a mixture of ETBE and ethanol or a mixture of them with hydrocarbons C ₅ +
EXAMPLES

 The following catalysts were used in the examples.

Amberlist-15 sulfocationionite with a particle size of 0.3-1.2 mm and a static exchange capacity (SOE) of 4.7 mg • equiv H ⁺ / g dry weight of the catalyst, KU-23 catalyst with a particle size of 0.4-1.4 mm and SOE = 4.1, Amberlist-35 catalyst with a particle size of 0.3-1.2 mm, SOE = 5.2, a molded sulfate ionite catalyst KIF with a cylindrical particle size of 6 (length) - 5 (diameter) mm.

 Further in the examples, the concentrations are given in wt.%.

 EXAMPLE 1

 Processing is carried out according to FIG. 1.

 An initial hydrocarbon mixture F containing 45% isobutene and 55% isobutane is used.

 In the reactors R-1 and R-2 loaded sulphocationite Amberlist-15. The total number of feed streams of ethanol (E) and the initial hydrocarbon mixture F corresponds to a molar ratio (MO) of ethanol: isobutene 1.6: 1.

 The ratio of ethanol flows 2a and 2b = 4.6: 1.

In the R-1 reactor, MO ethanol is supported: isobutene at an inlet of 1.3: 1, outlet temperature is 63 ^° C, a load of 2.6 l / l cat.h, while the conversion of isobutene is 81%.

In the R-2 MO reactor, ethanol: isobutene at the inlet is 1.75: 1, the outlet temperature is 60 ^° C, the load is 2.6 l / l cat.h, the isobutene conversion is 88%.

 Both direct-flow reactors R-1 and R-2 are tubular devices with heat removal due to a thermostatically controlled jacket through which refrigerant circulates.

 As a distillate of the K-1 column, a hydrocarbon stream containing isobutene 5.0%, ethanol 0.5% is selected in an amount of 0.58 kg / kg of feedstock.

 From the cube of the K-1 column, 0.91 kg / kg F of product is selected in the amount of 83.6% of ETFE and 16.0% of ethanol. The octane number of the product determined by the research method (RON) is 118.

 EXAMPLE 2

 Processing is carried out according to FIG. 1.

 An initial hydrocarbon mixture F containing 40% isobutene, 45% n-butenes and 15% butanes is used.

 The reactors R-1 and P-2 are loaded with sulfonic cation exchanger KU-23. The total amount of flows of E and F supplied to the system corresponds to MO ethanol: isobutene 3.2: 1. In this case, the ethanol supply is distributed between streams 2a and 2b in a ratio of 4.6: 1.

 The R-1 reactor is a shell-and-tube reactor with a heat due to the supply of refrigerant to the annulus: the R-2 reactor is an adiabatic type apparatus.

In the R-1 reactor, MO ethanol is supported: isobutene at an inlet of 4.0: 1, outlet temperature is 65 ^° C, a load of 2.0 l / l cat.h, isobutene conversion is 92%.

In the R-2 MO reactor, ethanol: isobutene at the inlet is 10.0: 1, the outlet temperature is 64 ^° C, the load is 3.0 l / l cat.h, the isobutene conversion is 92%.

 As a distillate of the K-1 column, a hydrocarbon stream containing isobutene 1.1% and ethanol 0.7% is selected in an amount of 0.62 kg / kg F.

 1.44 kg / kg F of product including ~ 50% ETBE and ~ 50% ethanol are taken from the bottom of the K-1 column. The product has RON = 119.

 EXAMPLE 3

 Processing is carried out according to FIG. 2.

 A hydrocarbon mixture F containing 45% isobutene and 55% isobutane is used.

 The molded ion-exchange catalyst KIF is loaded into the reactors R-1 and R-2, and the Amberlist-35 cation exchanger is loaded into the reactor R-3.

 The total number of supplied streams E and F corresponds to MO zanol: isobutene 1.35: 1, The ratio of ethanol flows 2a and 2b is 3.3: 1.

The heat removal in the tubular reactor R-1 is carried out by heating the reaction mass from a temperature of 50 ^° C at the inlet to 73 ^° C at the outlet of the apparatus, and also by circulating a portion of the reaction mixture cooled to 50 ^° C to the reactor inlet.

 In reactor R-1, MO ethanol is supported: isobutene at the inlet of 0.8: 1, a load of 2.0 l / l cat.h, while the conversion of isobutene is 69%.

In the reactor R-2, the outlet temperature is 48 ^o C, the load is 1.5 l / l cat.h, the total conversion of isobutene in the reactors R-1 and R-2 is 77.0%.

In the additional reaction zone R-3. MO ethanol: isobutene inlet 1.5: 1, outlet temperature 65 ^o C, load 2.0 l / l cat.h, isobutene conversion in P-3 - 83%.

 The hydrocarbon stream selected as a distillate of the K-1 column in an amount of 0.86 kg / kg F contains mainly isobutane, 5.9% isobutene, and 0.5% ethanol.

 From the bottom of the K-1 column, 0.58 kg / kg F of product is selected, including 89.0% ETBE and 10.7% ethanol, as well as 0.2% isobutene dimers. The product has RON = 118.

 EXAMPLE 4

 Processing is carried out according to FIG. 2. Use an initial hydrocarbon mixture F containing 45% isobutene and 55% isobutane.

 In the reactors R-1, R-2 and R-3 loaded sulfocationic catalyst Amberlist-35.

 The total amount of E and F flows supplied to the system corresponds to MO ethanol: isobutene 1.05: 1. The ratio of ethanol flows 2a and 2b is 14.8: 1.

Heat removal in the tubular reactor R-1 is carried out by heating the reaction mass from a temperature of 45 ^° C at the inlet to 62 ^° C at the outlet of the apparatus, as well as by circulating a portion of the reaction mixture cooled to 45 ^° C to the reactor inlet.

 In the R-1 reactor, MO ethanol is supported: isobutene at the inlet of 0.97: 1, a load of 2.0 l / l cat.h, while the conversion of isobutene is 87%.

 In the R-2 reactor, conditions close to isothermal are maintained due to the circulation of the coolant through a thermostatic jacket of the reactor.

In the reactor R-2, the outlet temperature is 45 ^o C, the load is 1.0 l / l cat.h, the total conversion of isobutene in the reactors R-1 and R-2 is 94.0%.

In the additional reaction zone of R-3 MO ethanol: isobutene at the inlet 1.5: 1, outlet temperature - 61 ^o C, load 1.1 l / l cat.h, the conversion of isobutene to R-3 - 90 ^o C.

 Selected as a distillate of the K-1 column in an amount of 0.83 kg / kg F, the hydrocarbon stream contains mainly isobutane, 1.3% isobutene, as well as 0.5% ethanol.

 0.56 kg / kg F of product including 96.8% ETBE and 3.0% ethanol is taken from the bottom of the K-1 column. The product has RON = 117.

 EXAMPLE 5

 Processing is carried out according to FIG. 2.

A hydrocarbon mixture F containing 10% isobutene, 40% butanes and n-butenes, 10% tert-pentenes, 35% pentanes and n-pentenes and 5% C ₆ hydrocarbons is used.

 In the reactor R-1, R-2 and R-3 placed Bayer sulfonate catalyst K-2631.

 The total number of supplied streams of E and F corresponds to E: tert-alkenes = 1.3: 1.

 The ratio of ethanol flows 2a and 2b is 5.1: 1.

 In the R-1 reactor, heat removal is carried out due to a thermostatically controlled jacket, the R-2 and R-3 reactors operate in adiabatic mode.

The ethanol is supported in the R-1 reactor: ethanol at the inlet is 1.05: 1, the outlet temperature is 70 ^o C, the load is 3.0 l / l cat.h, while the conversion of isobutene to R-1 is 72% , the conversion of tert-pentenes is 57%.

In the reactor R-2, the outlet temperature is 53 ^o C, the load is 2.0 l / l cat.ch. The total conversion of isobutene to P-1 and P-2 is 80%, tert-pentenes - 65%.

In the additional reactor R-3 MO ethanol: isobutene at the inlet 1.5: 1, outlet temperature - 65 ^o C, load 2.0 l / l cat.h, isobutene conversion 83%.

Selected as a distillate of the K-1 column in an amount of 0.41 kg / kg F, the hydrocarbon stream contains 95.9% butanes and n-butenes, 2.1% isobutene, 1% C ₅ hydrocarbons, and 1.0% ethanol.

The bottoms product of the K-1 column, taken in an amount of 0.76 kg / kg F, contains 21.9% ETBE, 14.8% ethyl tert-pentyl ether, 6.7% ethanol, and 56.6% C hydrocarbons ₅ -C ₆ . The product has a RON = 85.

 EXAMPLE 6

 Processing is carried out according to FIG. 2.

A mixture containing 20% isobutene, 35% n-butenes and 35% butanes (mainly isobutane) and a mixture F 'containing 20% tert-pentenes, 60% pentanes and n-pentenes and 20% C hydrocarbons are used as hydrocarbon feedstocks. ₆
Mixtures F and F 'are fed to reactor 1 in a weight ratio of 1: 1.

 The processing mode is supported analogously to example 5.

As a distillate of the K-1 column, a hydrocarbon stream containing 95.8% butanes and n-butenes, 2.3% isobutene, 0.9% C ₅ hydrocarbons, and 1% ethanol is withdrawn in an amount of 0.41 kg / kg F .

From the cube of the K-1 column in an amount of 0.76 kg per 1 kg of hydrocarbon feed (F + F '), a product is selected containing 21.8% ETBE, 14.8% ethyl tert-pentyl ether, 6.8% ethanol, 55.6% C ₅ -C ₆ hydrocarbons, as well as an admixture of ethyl tert-hexyl ether. The product has a RON = 86.

Claims (3)

1. A method of producing high-octane gasoline additives by contacting isobutene-containing hydrocarbon mixtures and ethanol with acidic (s) ionite (s) catalyst (s) in two or more direct-flow reaction zones and separating unreacted C ₄ hydrocarbons in the distillation zone from said reaction zones as at least one precedes the distillation zone and at least one is connected to the distillation zone as an additional reaction zone into which a side stream is discharged above the feed of the reaction s of the preceding reaction zone, and possibly an additional amount of ethanol, and from which the reaction mixture is returned to the distillation zone below the side sampling point, characterized in that the total molar amount of the initial and possibly recovered ethanol is fed to the process, exceeding the total molar amount of isobutene in the initial hydrocarbon mixture and ethanol in the distillation stream of unreacted hydrocarbons, and a high-octane mixture with a relative ethyl tert-b content is removed from the bottom of the distillation zone Tilova ester of from 50 to 97 wt.% ethanol and from 3 to 50 wt.% based on the sum of them.  2. The method according to claim 1, characterized in that ethanol is fed into the first reaction zone in an amount providing at the entrance to it a molar ratio of ethanol: isobutene of at least 0.8: 1, preferably at least 1: 1, and in an additional ( s) the reaction (s) zone (s) - in an amount providing a molar ratio of ethanol: isobutene at the inlet of at least 1.5: 1, preferably more than 2: 1. 3. The method according to claims 1 and 2, characterized in that, as a raw material in the composition of the isobutene-containing hydrocarbon mixture or in addition to it, C ₅ hydrocarbons, including tert-pentenes and, possibly, are fed into the reaction zone (s) hydrocarbons with a large number of hydrocarbon atoms and from the bottom of the distillation zone remove a product containing ethyl tert-butyl ether, ethyl tert-pentyl ether, ethanol and C ₅₊ hydrocarbons.

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