RU2357948C2 - Method of alkene(s) and higher-boiling reagent reaction - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention refers to method of reaction of alkene(s) contained in hydrocarbon stream, and in a reaction-rectifying system provided with rectifying sections and in between reaction zones with subnatant catalyst. The fluid is poured from the top of each overlying zone to the bottom of underlying zone. It is followed with partial disperse passing of vapour flow from underlying zone through each reaction zone. Thus residual vapour flow from each underlying zone is backflow to the top of overlying reaction zone through overflow space to poured fluid. As a rule, higher-boiling reagent is nontertiary alcohol, carboxylic acid or benzene, while essential reaction product is ether, ester or alkylbenzene.

EFFECT: improved method.

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Description

The invention relates to the field of chemical interaction of alkenes and higher boiling substances in the presence of sulfocationic catalysts.

Known methods / S.Yu. Pavlov and others. Chemical industry, 1995, No. 5-6, p.9-15 / chemical interaction of alkenes supplied in the hydrocarbon mixture, and a higher boiling substance, in particular alcohol, in the reaction-distillation a system including distillation zones and a reaction zone located between them with a sulfocationite catalyst, in which counter-current movement of liquid and steam flows. The disadvantage of the methods is the need for a very large cross section of such a reaction zone and the difficulty of uniformly distributing the liquid stream over its cross section, especially in high-power productions.

The known method / Pat. RU-2063956, 07.20.96 / chemical interaction of alkene (s) and a higher boiling substance (alcohol) in a reaction-distillation apparatus having between the distillation zones several reaction zones with a catalyst partially or completely immersed in a liquid equipped with steam distribution devices in the lower part and overflow devices, through which liquid from each overlying reaction zone enters the lower part of the underlying reaction zone.

The disadvantage of this method is the high steam load of the reaction zones and the need for their large cross section, significantly exceeding the cross section of the reaction zones.

Also known method / Pat. RU-2064919, 08/10/96 / chemical interaction of alkene (s) and a higher boiling substance (alcohol) in an apparatus with separate distillation zones and several reaction zones, in each of which there is a layer of sulfonic ion catalyst immersed in a liquid through which part ( 5-70%) of the steam flow coming from the underlying zone, and the remaining part is passed into the upper part of the upstream zone through separate hollow vertical channels.

The disadvantage of this method is the absence of mass transfer contact between the vapor and the liquid in the indicated vertical hollow channels or overflows and the need to install mass transfer plates between the reaction zones for transferring part of the alkene (s) from the steam stream to the downward flowing liquid stream. At the same time, the space of the reaction zone is cluttered with transfer and vapor transmission channels, or there is a need for the location of these vapor transmission channels outside the apparatus.

We found a method that does not have these disadvantages.

We declare:

A method for reacting an alkene (s) containing (them) in a hydrocarbon stream and a higher boiling agent in the presence of a sulfoionite catalyst in a reaction-distillation system having distillation zones and reaction zones located between them with a catalyst immersed in liquid, overflowing liquid from the upper part of each overlying zone to the lower part of the underlying zone and dispersed transmission of part of the steam stream from the underlying zone through each reaction zone, characterized in that steel part of the vapor flow from each zone underlying passed into the upper portion overlying the reaction zone through the overflow space countercurrently to the liquid transfused.

As a complement to the specified method, we also declare methods, characterized in that:

- the steam stream passing through the specified overflow space is dispersed, preferably evenly, over the cross-section of the overflow space;

- alkene (s) containing the hydrocarbon stream is fed at least below the lower reaction zone, and the indicated higher boiling point reagent is supplied at least to the upper reaction zone or the distillation zone located above it;

- alkene (s) containing the hydrocarbon stream is distributed into several streams and part of them is fed into the intermediate reaction zones and / or between them;

- a stream of a higher boiling reagent is distributed into several streams and part of them is fed into the intermediate reaction zones and / or between them;

- said higher boiling point reagent is non-tertiary alcohol or carboxylic acid or benzene and the main reaction product is ether or ester or alkyl benzene;

- when alkene (s) reacts with a higher boiling agent, di- and / or trimers of alkenes are also formed, and the resulting substances are removed from the exhaustive distillation zone.

In the proposed method, the combined countercurrent movement of liquid and steam flows in the system as a whole with their direct-flow or direct-flow-cross movement in each reaction zone is combined. Due to this, a high conversion of the reacting substances is achieved with a relatively small cross section of the reaction zones, the absence of local overheating in the reaction zones and the removal of high molecular weight impurities from the catalyst with a liquid stream.

The combination of countercurrent fluid flow and the transmission of part of the vapor stream in a single transfer space simplifies the design and provides the necessary mass transfer between the liquid stream and the steam stream richer in alkene (s).

The number of reaction zones may vary depending on the requirements for complete conversion and other circumstances. Preferably, the number of reaction zones is from 3 to 10.

The possibility of additional placement of mass transfer devices between the reaction zones is not excluded, however, their number is reduced, or they are not installed at all.

Unreacted (e) hydrocarbon (s) (possibly with an admixture of a higher boiling point reagent), at least for the most part, are removed from the top of the strengthening distillation zone. The products of chemical interaction are removed mainly from the bottom of the exhaustive distillation zone.

The placement of these reaction and distillation zones in one column apparatus is optional. It is possible to place them in different devices connected by countercurrent liquid and steam streams in accordance with claim 1.

The possibility of combining the proposed reaction-distillation system with the previous direct-flow reaction zone, in which a partial chemical interaction of the reactants is carried out, is not ruled out.

If necessary, the distilled hydrocarbon mixture and / or the mixture of reaction products is subjected to separation using known methods (distillation, aqueous extraction, heterozeotropic drying, etc.).

The application of the invention is illustrated in figures 1-3 and examples. Specified in figures 1-3 and in the examples does not exclude the possibility of using other technical methods, subject to the signs specified in claim 1 of the claims.

In Figs. 1 and 2, the legend is: RT - distillation plate, RU - dispensers for steam streams, PO - through holes for steam, W - liquid streams, V - steam streams. Shaded (crossed out) catalyst beds.

The liquid flow W from each overlying zone enters the lower part of the underlying reaction zone or, accordingly, into the mass transfer (distillation) zone.

The vapor stream V on top of each zone located below the reaction zone partially passes through the switchgear RU into the overlying reaction zone and partially through the through holes of PO (Fig. 1) enters the overflow space, sparges through the overflowing liquid and enters the upper part of the overlying reaction zone .

The variant depicted in FIG. 2 differs from FIG. 1 in that the steam flow directed from the top of the reaction zone into the overflow space is dispersed in this space using a switchgear RU, which contributes to better mass transfer between the rising steam and the flowing liquid.

Figure 3 shows a diagram of the reaction-distillation system as a whole. The notation is: RZ - reaction zones with a catalyst, URZ and IRZ - strengthening and exhaustive distillation zones, BP - a higher boiling point reagent, KP - bottoms stream (product).

The initial (e) hydrocarbon (s) arrives (ly) through line 1 (then, possibly along lines 1a, 1b, 1c, 1g, 1d), BP - through line 2 (further possible along lines 2a, 2b, 2c). The product (s) of reaction (s) and the unreacted portion of BP are discharged via line 3, unreacted (e) hydrocarbon (s) via line 4 (possibly via line 4a). Perhaps part of the product (s) and BP are withdrawn along line 5.

Five reaction zones are conditionally selected. Their number can be from 2 to 50, more realistic - from 3 to 10. The reaction and both distillation zones do not have to be located in one column. Perhaps their location in two or more devices connected by liquid and gas streams and forming a single reaction-distillation system in compliance with the signs specified in paragraph 1 of the claims. The upper (strengthening) distillation zone does not have to have a reflux condenser. It is possible to supply a high-boiling reagent to its upper part to dissolve part of the vapor stream and create internal reflux for rectification.

In the examples, the concentrations are given in% mass.

Legend: MTBE - methyl tert-butyl ether, ETBE - ethyl tert-butyl ether, VBA - sec-butyl acetate, IPB - isopropylbenzene, UK - acetic acid, BIF - butane-isobutene fraction, BBP - butane-n-butene fraction, PPF - propene-propane fraction, RP - reaction zone (s), URZ-strengthening distillation zone, IRZ - exhaustive distillation zone, D - distillate, KP - bottoms product, R - reflux ratio, SOE - static exchange the catalyst capacity in mEq / g · cat, V ₁ / V and V ₂ / V - respectively, the fraction of the vapor stream V from the top of the reaction th zone passed (V ₁ ) through the overlying reaction zone and directed (V ₂ ) through the overflow space.

An example of the prototype RU-2064919.

Get MTBE from BIF and methanol. In the middle part of the distillation column there are 3 reaction zones with a catalyst, between which there are three distillation plates. A sulfonated ion catalyst KIF (SOE = 3.6) is used.

The prototype does not indicate the dimensions of the cross sections (or diameters) of the reaction zones. Further comparison is carried out using the loads of the reaction zones in the vapor stream passed through the catalyst.

10.9 t / h of BIF (45% isobutene) and 2.74 t / h of methanol are fed, which corresponds to an isobutene conversion of ~ 99% and a selectivity of ~ 99% to obtain 7.4 t / h of MTBE (99.1% of the basic substance ) The output of distillate (isobutane with 3.2% methanol and 0.75% isobutene) is 6.3 t / h, R = 3.

In URZ, the steam load is 25.2 t / h. The share of the vapor stream V ₁ / V in the upper, middle and lower RE is 0.05, 0.4 and 0.7, respectively. The steam load in the RE is from 1.3 (in the upper RE) to 8.4 t / h. MTBE production per unit volume of the catalyst is 0.92 kg / l cat · h.

Other examples illustrate the invention.

Example 1

According to figures 1 and 3, MTBE is obtained from BIF (45% isobutene) and methanol (T _bale = 64 ° C). In the middle part, 5 reaction zones are used (~ 1 m catalyst layer in each). The KIF-T catalyst is used (cylinders with a diameter of 6 mm and a length of 6-8 mm, SOE = 3.6). The temperature in the reaction zones is 60-70 ° C, R = 2.3. 11.0 t / h of BIF and 2.7 t / h of methanol are fed.

The steam load in the URZ is 20.5 t / h. V ₁ / V in the reaction zones (from upper to lower) 0.08-0.15.

The vapor load in the RE with the catalyst is from 1.6 (in the upper RE) to 2.0 t / h (in the lower RE), respectively. At the indicated loads, taking into account the 25-30% porosity (fraction of free cross-section) of the catalyst, the required diameter of the reaction zones does not exceed the diameters of the distillation zones, which makes it possible to place the reaction and distillation zones in a single column with a diameter that does not change in height.

Output: 7.6 t / h KP (99.4% MTBE, 0.3% methanol and 0.3% isobutene dimers) and 6.2 t / h isobutane distillate containing 0.4% isobutene and 2.8% methanol.

Compared with the prototype, a higher MTBE purity and isobutene extraction degree are achieved, a 1.3 times smaller R and four times smaller cross-section is required (based on the load in the lower RE).

Example 2

ETBE is obtained from BIF (45% isobutene) and ethanol (T _bp = 78.3 ° C). The processing is carried out according to figure 2 and 3. The catalyst plant, similar to example 1. In the system 4, reaction zone with a catalyst height of 1.1 m each. The temperature in the reaction zones is 55-65 ° C, R = 2.0.

11.0 t / h of BIF and 4.3 t / h of ethanol are fed.

The steam load in the URZ is 18 t / h. V ₁ / V in the reaction zones, increasing from upper to lower RE, 0.15-0.3. The vapor load in the reaction zones is from 2.7 t / h in the upper zone to 3.3 t / h in the lower zone.

When the porosity of the catalyst is 25-30%, the required diameter of the reaction zones does not exceed the required diameter of the distillation zones.

9.3 t / h KP (97.6% ETBE, 2.2% ethanol and 0.2% isobutene dimers) and 6 t / h isobutane distillate (0.3% isobutene, 0.1% ethanol) are withdrawn.

Example 3

Get BWA from acetic acid (AC) and BBP (in it 50% n-butenes) according to figures 2 and 3.

Use a coarse-grained sulfonate catalyst with spherical granules with a diameter of 4-5 mm and SOE = 2.7. There are 4 reaction zones in system 4. The temperature in them is 90-100 ° C, R = 1.7.

Serve 100 kg / h BBF and 65 kg / h UK. The steam load in the URZ is 137.7 kg / h. The ratios V ₁ / V in the reaction zones are almost the same and amount to 0.25. The steam load in the RE is from 34.4 kg / h in the upper RE to 30.0 in the lower RE.

When the porosity of the catalyst is 25%, the required diameters of the reaction and distillation zones are almost the same.

51.0 kg / h of butane distillate (2% n-butenes in it) and 114 kg / h KP (85.7% of VBA, 14.0% of AC and 0.3% of n-butenes dimers) are removed. After distillation from the UK, 98 kg / h of a stream with 99.7% VBA and 0.3% n-butenes dimers is obtained.

For comparison: in a similar process with countercurrent vapor-liquid reaction zones, the cross section of the reaction zones and the loading of the catalyst are 3.0-3.5 times greater than in the proposed method.

Example 4

Get IPB from benzene and PPF (75% propene in it) according to figures 1 and 3.

Use 5 reaction zones with a coarse-grained sulfocationic catalyst similar to Example 3. The temperature in the reaction zones is 70-80 ° C.

A high boiling point reagent, benzene, is fed to the upper part of the strengthening distillation zone, where it absorbs part of the C ₃ hydrocarbon (s) and creates internal reflux. The internal reflux number, defined as the ratio of the sum of C ₃ hydrocarbons flowing down to the output vapor stream (mainly propane), R _int = 4.5-5.0.

Serve 100 kg / h PPF and 520 kg / h of benzene. The steam load in the URZ is 178.2 kg / h. The ratio V ₁ / V in the reaction zones: in the upper RE - 0.2, in the lower RE - 0.3 (in the other RE - intermediate values). The steam load in the upper RE - 35.6 kg / h, in the lower RE - 36 kg / h.

When the porosity of the catalyst is 25%, the required diameters of the reaction and distillation zones are almost the same.

Output: 589 kg / h KP (67.4% benzene, 30.7% IPB, 1.7% diisopropylbenzene, 0.2% di- and trimers of propene) and 31 kg / h of propane distillation via line 4a (96.8 % propane and 3.2% propene).

Example 5

Get tert.butylphenol (TBP) from BIF (in it 45% of isobutene) and phenol (T _bale = 182.2 ° C).

In the middle part, 2 reaction zones are used (~ 0.9 m each of a catalyst layer — sulfonated “crosslinked” polystyrene on macroporous silica gel (sphere diameter 4 mm, СОЕ = 2.1). The temperature in the reaction zones is 80-95 ° С), R = 1.8. 1.87 t / h of BIF and 1.5 t / h of phenol, 1.0 t / h of cyclohexane are fed. The ratio V ₁ / V in the reaction zones: in the upper RE - 0.1, in the lower RE - 0.14.

Withdraw: 1.05 t / h of isobutane distillate (~ 2% of isobutene in it) and 3.32 t / h of cubic product containing 66.6% of TBP, 30.1% of cyclohexane, 2.0% of phenol, 1.3 % isobutene dimers. After distillation (and return to the reaction), cyclohexane fractions give 2.2 t / h of TBP.

Claims (7)

1. A method of reacting alkene (s) containing (them) in a hydrocarbon stream and a higher boiling point reagent in the presence of a sulfoionite catalyst in a reaction-distillation system having distillation zones and reaction zones located between them with a catalyst immersed in a liquid and liquid overflows from the upper part of each overlying zone to the lower part of the lower zone and dispersed transmission of part of the steam stream from the lower zone through each reaction zone, characterized in that the rest of the vapor flow from each zone underlying passed into the upper portion overlying the reaction zone through the overflow space countercurrently to the liquid transfused. 2. The method according to claim 1, characterized in that the steam stream passing through the specified overflow space is preferably dispersed uniformly over the cross section of the overflow space. 3. The method according to claim 1, characterized in that the alkene (s) containing the hydrocarbon stream is fed at least below the lower reaction zone, and the higher boiling point reagent is fed at least to the upper reaction zone or the distillation zone located above it. 4. The method according to claim 1, characterized in that the alkene (s) containing the hydrocarbon stream is distributed into several streams and part of them is fed into or between intermediate reaction zones. 5. The method according to claim 1, characterized in that the stream of a higher boiling reagent is distributed into several streams and part of them is fed into the intermediate reaction zones and / or between them. 6. The method according to claim 1, characterized in that said higher boiling point reagent is non-tertiary alcohol or carboxylic acid or benzene, and the main reaction product is ether or ester or alkyl benzene. 7. The method according to claim 1, characterized in that during the interaction of the alkene (s) with a higher boiling agent, di- and / or trimers of alkenes are also formed, and the resulting substances are removed from the exhaustive distillation zone.

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