SU587855A3 - Method of preparing a high-octane fuel component - Google Patents

Description

(54) METHOD OF OBTAINING A HIGH-OCTANE FUEL COMPONENT

The invention relates to a method for producing a high-octane component of a fuel by alkylating isoparafins with olefinic hydrocarbons.

Hydrocarbons Cs-C i o, usually obtained by alkylation and called alkylate, are widely used as a component of the mixture in the production of motor fuel, as well as to improve the total octane number of gasoline, due to the high octane number of rio.

In industrial conditions, isobutane is used as isoparaffinic hydrocarbons, and propylene and / or butylenes are used as olefinic hydrocarbons, and the process is carried out in the presence of a catalyst — hydrofluoric acid, sulfuric acid, and other similar acidic substances.

At the end of the alkylation, the reaction mixture is divided into a hydrocarbon and catalyst phases in a settling tank, the catalyst is recycled, and the hydrocarbon phase is subjected to further processing, for example, it is fractionated.

It is advisable to take isoparaffin hydrocarbons in a large molar excess with respect to olefinic hydrocarbons (10: 1 30: 1).

The use of a large excess of isoparaffin hydrocarbons leads to an improvement in the quality of alkylate.

However, in order to isolate unreacted isoparaffin hydrocarbons and recycle them to the process, it is necessary to use equipment of high productivity, which leads to increased costs (not economically profitable).

Known (1 method of producing high-octane gasoline component by catalytic alkylation of isoparaffins with light and heavy olefins. Isoparaffins together with the same: olefins and a catalyst, preferably 88-92 / o-hydrofluoric acid, are fed to the upper part of the tubular reactor, and the light olefins are in its middle part.

The alkylation temperature in the first stage is 4.4 -18.3 ° C, in the second stage 18.3-32.2 ° C. The acid concentration in both stages is the same.

However, with a long contact time with the catalyst, cracking of the product obtained in the first stage and other side reactions are observed, which leads to a decrease in the yield of alkylate and a deterioration in its quality.

Also known (2) is the method of obtaining the view co-octane component of the fuel by alkylation of isobutane with propylene, to buds. . Alkylation with various olefins Pro: 4 1T in separate devices in the presence of hydrofluoric acid. The temperature of alkyl rinoin is 18.8-35 and 35-51 ° C with alkyl bilobenyl butenes and propylene, respectively. The reaction mixtures from separate devices are divided into one settling tank. The acid phase is recycled to individual units. As a result, the concentration of hydrofluoric acid (88-95 / o) used in the two devices is the same, although the temperature of the alkaline solution in each of the devices is different.

The indicated process, which requires the use of a large molar excess of isoparaffin in the two reactors, is even less economically advantageous than the previous one.

f The purpose of the invention is to simplify the technology of the process - is achieved by the fact that the alkylation of isobutane with propylene and butylene is carried out in two stages, and the alkylation in the first stage is carried out with propylene in the presence of 95-EE / o-hydrofluoric acid at 32-40 ° C the subsequent separation of the catalyst phase from the hydrocarbon phase and the contacting of the latter with butylene, in the second stage at 20-32 ° C in the presence of 75-90 / o-hydrofluoric acid.

The drawing shows a process diagram.

The isobutane entering through conduit I, n-propylene fed via conduit 2, is mixed and introduced via conduit 3 to reactor 4, where the catalyst is located. The temperature of the reaction mixture is about 32 ° C, the pressure is sufficient to maintain the reactants in the reactor in the liquid phase. The reaction catalyst containing catalyst, alkylated hydrocarbons, isobutane and propylene, is removed from the reactor and fed through line 5 to a sump 6. i

The catalyst phase is withdrawn through line 7 and the pump 8 is recycled to reactor 4.

A small part of the catalyst phase is diverted through line 9 to regeneration. Fresh and / or regenerated catalyst containing, for example, 97% hydrofluoric acid, through pipelines 10 and 11 is fed to the reactor 4.

The hydrocarbon phase containing alkylated hydrocarbons, isobutane and possibly some fluoroalkyls is removed from the sump 6 via line 12. j

The butylenes supplied through line 13 in line 12 are displaced with the hydrocarbon phase and introduced through line 14 into the reactor .15, where 90 / oHa hydrofluoric acid is located. The temperature of the liquid phase in reactor 15 is about 32 ° C. At the end of the alkylation, the reaction mixture is withdrawn from reactor 15 and sent via pipeline 16 to the reaction chambers at 17, where it is kept for some time at the temperature and pressure of alkylation. From the reaction chamber, the mixture is withdrawn through conduit 18 and transferred to sump 19.

From the settling tank 19, a heavier phase is discharged by 1U pipeline 20 and pump 21 through conduit 22 is fed to reactor 15. A small part of the catalyst phase is fed (5 conduit 23 is diverted to regeneration. Fresh and / or regenerated catalyst via pipeline 5 24 is fed to pipeline 20.

The hydrocarbon phase, containing alkylate and unreacted isobutane, from clarifier 19 through line 25 is sent to fractionation, for example, to a stripping column, from which isobutane is preferably

0 is returned to the reactor 4, and the alkylate is fed to further separation.

The isoparaffins and olefins used in the process are produced on an industrial scale.

Commodity isobutane may contain some amount of propane and butane.

Of the butylenes, it is best to use pure butene-1, butene-2, isobutylene, or a mixture of two or all butylene isomers. A mixture of butylenes with some amylene or other heavy olefins may be used.

Olefiiy may contain small amounts of hydrocarbons, such as paraffins, isoparaffy, ethylene, propylene.

It is possible to use pure propylene, or propylene containing small amounts of paraffins, isoparaffins, ethylene, butylenes.

Commodity propylene contains propylene and propane. It is best of all that heavy olefia is practically free from the use of light olefin n, in addition to that light olefin is almost free from the heavy olefin used. For example, isoparaffin may contain (in wt.%): 95 isobutane, 1 propane and 4 n-butane, heavy olefin -

40 butnlenes, 45 isobutane and 15 n-butane and light olefin-60 propylene and 40 propane. The catalyst used in the first stage of alkylation contains 95-99% titrated acid, water, and. I-5% hydrocarbon.

The catalyst used in the second stage, alkylated, contains 75-90% titrated acid, 0.1-1% water and 10-25% hydrocarbons.

- Preferably, the alkylation temperature in the first stage is 32-40 ° C, pressure

5 sufficient to maintain the catalyst’s reactants in the liquid phase, contact time 0.1–20 min, molar ratio between isobutane and propylene 20: 1–30: 1, volume ratio between catalyst and hydrocarbons 0 ,.

It is advisable to maintain a temperature of 20-32 ° C, a pressure sufficient to maintain the reactants and catalyst in the liquid phase, and a contact time of 0.1-20 minutes in the second stage of the alkllation.

It is best to submit the hydrocarbon phase from the first stage and heavy olefin containing butylenes to the second stage with a molar ratio between butylenes and hydrocarbon phases of 1: 20-1: 30 and a volume ratio between the catalyst and hydrocarbons of 0.5: 1 -2: one .

In Examples 1-8, the process is carried out in a continuous scheme, after the first reactor (only part of the hydrocarbon phase is mixed with olefin, and the rest is loaded into the second reactor.

Example /. Propylae is mixed with isobutane (molar ratio 1:24) and is fed and the reactor is alkylated (0.5 mol / h of propylene and 12 mol / h of nzobutane). At the same time, the catalyst is charged with (in wt.%): 95 hydrofluoric acid ,

4 organic diluent and I water. The volume ratio between the catalyst and hydrocarbons is 3: 2; the reaction mixture is kept for 10 minutes at a temperature of 40 ° C and a pressure of 5 atm.

The contact time is defined as the quotient of the division of the reactor volume by the total volume of reagents and catalyst loaded for 1 min.

The reaction mixture is withdrawn from the reactor, sent to a sump, kept in it.

5 min, the catalyst phase is separated and returned to the alkylation reactor, and the hydrocarbon phase is withdrawn from the settling tank and separated.

The separated hydrocarbons after mixing with butylenes (0.5 mol / h). {Are loaded into the second alklylation reactor, identical to the first. At the same time, a catalyst containing (in wt. ° / o): 75 hydrofluoric acid, 24 organic diluent and I water is fed to the second reactor. The volume ratio between acid and carbon is 3: 2. The reaction mixture was kept for 10 minutes at a temperature of 32 ° C and a pressure of 15 atm, removed from the reactor and sent to a sump. The catalytic phase is recycled to the alkylation reactor for further use. The hydrocarbon phase is withdrawn from the settling tank and hydrocarbons C are separated, and the more severe ones, which are the target alkylate.

The octane number of alkylate according to the research method is 95.2, according to the motor method 92.5.

Example 2. Butylenes are mixed with isobutane (molar ratio G: 24) and loaded into an alkylation reactor (0.5 mol / h of butylenes and 12 mol / h of isobutane). At the same time, a catalyst containing (in wt.%) 74 hydrofluoric acid, 24 organic diluent and I water is fed into the reactor. The volume ratio between catalyst and hydrocarbons is 3: 2.

The reaction mixture was kept for 10 minutes at a temperature of .32 ° C and a pressure of 15 atm, removed from the reactor, sent to a sump and kept in it for 5 minutes.

The catalyst phase is withdrawn from the settling tank to the reactor.

The hydrocarbon phase is removed from the reactor, hydrocarbons are separated and, after mixing with propylene (0.5 mol / h), are loaded into the second reactor, into which a catalyst containing (in wt.%) At the same time: 95 hydrofluoric acid, 4 organic diluents and I water. The volume ratio between catalyst and hydrocarbons is 3: 2. The reaction mixture was incubated for 10 minutes at a temperature of 40 ° C and a pressure of 15 atm. sent to the sump and kept in it for 5 minutes. Catalyst. the phase is withdrawn from the settler and returned to the reactor. The hydrocarbon phase is removed from the settler and the hydrocarbons Cj and the heavier ones are separated (target alkylate). The octane number is 11 (For research method 94.5, for motor method 92.0.

Some: a) reduction in the octane number of the half-valued alkylate as compared with example I is possibly related to the destruction of the alkylate obtained in the first reactor in the second reactor, where the conditions are more severe.

Changing the order of alkylation has almost no effect on the quality of the alkydum obtained.

Example 3. Propylene is mixed with isobutane (molar ratio 1:24), loaded into the reactor (12 mol / h isobutane, 0.5 mol / h propylene) and a catalyst containing (in wt.%) Is introduced into it : 95% hydrofluoric acid, 4 organic diluents and 1 water. The volume ratio between catalyst and hydrocarbons is 3: 2. The reaction temperature is 32 ° C; the pressure is 5 atm; the contact time is O min. The reaction mixture is removed from the reactor,

incubated for 5 minutes in a settling tank, separating the catalyst phase and returning it to the reactor. The hydrocarbon phase is removed from the settling tank, the hydrocarbons are separated, mixed with butylenes (0.5 mol / h) and fed to the second reactor.

At the same time, a catalyst containing (in 8%.%): 89 hydrofluoric acid, 10 organic diluent and I water is loaded into the reactor. The volume ratio between catalyst and hydrocarbons is 3: 2. Temperature - 32 ° C, pressure 15 atm, contact time

10 min.

The reaction mixture is withdrawn from the reactor, allowed to stand in the sump for 5 minutes, the catalyst phase is withdrawn and returned to the reactor. The hydrocarbon phase is removed from the reactor,

Cs and heavier hydrocarbons are separated and recovered as alkylate. The octane number for the pure research method is 96.2.

Changing the temperature in the first reactor using a more concentrated acid in the second reactor as compared with example I results in a higher quality product.

By adjusting the conditions in the second stage of the process (milder conditions), it is possible to prevent the destruction of the alkylate and to obtain a product with a higher octane number:

Example 4. A mixture of butylenes and isobutAA (molar ratio 1:24) was charged to the reactor (0.5 mol / h of butylene, 12 mol / hour of isobutane) and a catalyst containing (in wt.%): 75 hydrofluoric acid, 24 organic diluent and I water. The volume ratio between the catalyst and hydrocarbons. 3: 2. Temperature 32 ° С, pressure 15 atm, contact time 10 min.

The reaction mixture is removed from the reactor,

incubated in the sump for 5 minutes, the catalyst 1 () oz is returned to the reactor, and the hydrocarbon phase is sent to the second reactor, pre-mixed with propylene (0.5 mol / h). Simultaneously, the q reactor serves 0.5 mol / h of catalyst, containing (in w / v) 95 hydrofluoric acid, 4 organic diluent and I water. The volume ratio between the catalyst and hydrocarbons is 3: 2. Contact time 10 million, temperature 32 ° C, pressure 15 atm.

The reaction mixture is withdrawn from the reactor, kept in the sump for 5 minutes, and the catalyst phase is returned to the reactor, and the hydrocarbon phase is withdrawn from the sump and fractionated. Hydrocarbons C; and the heavier ones are separated from light hydrocarbons and are used as target alkylate. Research octane number 95.

Comparison of examples 1 and 3 with examples 2 and 4 (change in the order of alklylation: isobutane-f propylene h-butylenes or isobutane + butylenes + propylene) confirms the flexibility of the proposed method, which allows to obtain high quality alkylate.

Example 5. A mixture of propylene and isobutane (molar ratio 1: | 2) is loaded into the first reactor, a catalyst is fed into it, containing (in wt.%): 95 fluorophorescentric acid, 4 organic diluents and I water. The volume ratio between catalyst and hydrocarbons is 3: 2. Temperature C, pressure 15 atm, contact time 10 min.

The reaction mixture is withdrawn from the reactor, kept in the sump for 5 minutes, the catalytic phase is returned to the reactor, and the hydrocarbon phase is withdrawn from the sump and separated.

A mixture of butylene and isobutane (molar ratio 1:12) is loaded into the second reactor, identical to the first (6 mol / h of isobutane, 0.5 mO / h of butylenes) and a catalyst containing (in wt.%) Is introduced into it: 90 hydrofluoric acid, 9 organic diluent and I water. The volume ratio between the catalyst and hydrocarbons is 3: 2.

The reaction mixture was kept for 10 minutes at a temperature of 32 ° C and a pressure of 15 atm, removed from the reactor, sent to a sump, left there for 5 minutes, the catalyst phase was returned to the reactor, the hydrocarbon phase was removed from the sump and combined with a hydrocarbon phase withdrawn from the first clarifier. Hydrocarbons Cg and heavier hydrocarbons are separated from lighter hydrocarbons and the desired alkylate is obtained. The octane number of the pure research method is 94.5.

Thus, the alkylate obtained in examples 1 and 3 is superior in quality to the alkylate obtained in example 5.

Example 6 A process with a molar ratio of 24: 1 isobutane and propylene, 24: 1 isobutane and butylene, and 12: 1 isobutane and olefins is carried out. Reagents are loaded into the reactor (12 mol / h of isobutane, 0.5 mol / h of butylenes, 0.5 mol / h of propylene) and at the same time a catalyst containing

(in wt./about): 89 hydrofluoric acid, 10 organic diluent and I water. The volume ratio between catalyst and hydrocarbons is 3: 2. Temperature 32 ° С, pressure 15 atm, contact time 10 min.

The reaction mixture is withdrawn from the reactor, kept in the sump for 5 minutes, the catalyst phase is returned to the reactor, the hydrocarbon phase is withdrawn from the settler and fractionated. Hydrocarbons C; and more severe are isolated as octane alkylate using the net research method of 93.5.

When comparing the quality of the alkylate obtained in examples 1 and 3 with the quality of the alkylate obtained in example 6, it can be seen that the proposed method allows you to get more

high quality when using the same quantities of reagents.

Example 7. The process is carried out analogously to Example 3, and at a temperature in the second reactor of -20 ° C. Hydrocarbons C ,,, hydrocarbons C and lighter are separated from the hydrocarbon phase. For hydrocarbons Cs, the octane number by the research method is 96.2 (ravioceno product of Example 3, which confirms the flexibility of the proposed method).

Example 8. The content of C 9 or more heavy hydrocarbons in the alkylates obtained in examples 2, 3 and 7 is determined. The alkylate obtained in examples 3 and 7 contains only 4% by weight of hydrocarbons C n more heavy, and the alkylate obtained in Example 2 is 6.2 wt. / o hydrocarbons Cj and more heavy only due to a change in the order of alkylation. The alkylates obtained by the known method in examples 5 and 6 contain 5 wt.% O Cj and heavier hydrocarbons. Thus, the proposed method can produce alkylate, in which the end point of the boiling point is significantly lower than that of the alkylates obtained by a known method.

Claims (2)

1. US patent number 3169153, cl. 260-683,1965. 2. US Patent No. 3544651, cl. 260-683.45. 1968.