EP1569747A1

EP1569747A1 - Device for conditions of chemical technologies and its application

Info

Publication number: EP1569747A1
Application number: EP03717864A
Authority: EP
Inventors: Zuzana Gogov; Vladimir Camaj; Milan Hronec; Frantisek Stancek
Original assignee: Novacke Chemicke Zavody AS
Current assignee: Novacke Chemicke Zavody AS
Priority date: 2002-11-26
Filing date: 2003-04-04
Publication date: 2005-09-07
Also published as: SK16762002A3; SK285692B6; PL375505A1; RU2005120243A; WO2004047980A1; AU2003222562A1

Abstract

This invention describes device that can be used in chemical technologies, is suitable for systems with coexistence of several phases. The device has a shape of two concentric vertical cylinders, inside of which the liquid circulates as a result of difference in density of the fluid at a given time present in the inner and the outer cylinder of the device. In the longitudinal section, the inner cylinder comprises at least one reaction zone (R2, R4), the corresponding number of the related sections and inner part of the separator (D5). The reaction zones ordinarily contain packing loaded in segments on a support grid. The related sections comprise a gas distributor (S1). The bottom section contains a jet nozzle (B) for a liquid reagent introduction, valves (C, E) for third phase discharge, gas distributor (S2) in its upper part and in the space below the distributor, there are circular openings round the body of the inner cylinder. These openings allow the circulating liquid to be sucked in from the outer into the inner cylinder. The device enables reactions of olefin hypochlorites production to be carried out with gaseous chlorine, olefinically unsaturated compound and water in the presence of aqueous solution of the product.

Description

Device for conditions of chemical technologies and its application

Field of the invention

The subject of the present invention comprises a device for conditions of chemical technologies and a way of its application.

Prior art

For the selected reaction types there are known classical stirred reactors, horizontal columns IM with several stirred partitions, tubular reactors 121, and bubble columns /3, 4/ in patents. With respect to the fact that the selectivity of the given reactions and the conversion of starting materials that are continuously fed to the reactor are dependent on strict division of the respective reaction zones, on concentration of the reagents in a particular reaction zone, on the mass transfer rate through the gas/liquid interface, on the interfacial area, and on homogenization of the reaction medium, these sorts of reactors don't meet the demand on the process to be carried out with high selectivity at an economically favourable regime

- A reactor of the airlift type with external loop has been known This device is made of steel with basalt walls The gaseous reagents are dispersed in the liquid bulk by means of plate spargers with circular openings The internal circulation is given by introduction of compressed gas, and it's impossible to either calculate or measure it accurately and alter it in a suitable way, at a need The discharge gas carries along some portion of the reaction products and thus presents an ecological burden to the whole technology The phase balance violation caused by insufficient gas dispersion brings about total conversion of the process, which has to be stopped consequently Such a lapse causes significant economical losses

Several methods of increasing selectivity of the chosen reactions are patented Generally, from the chemical point of view, there is, in most of the cases, pointed out a catalytic activity of (Fe³⁺) ions 151, salts, mainly chlorides, carbonates, sulphates, and hypochlontes of I A and II A metals of the Periodic Table of Elements and amphoteπc metals /6, 7, 8, 9/ The respective processes appea economically disadvantageous, considering that the claimed catalytic activity hasn't been confirmed in some cases, or with regards to the concentration of the catalyst employed, or because of simultaneous catalysis of undesired side reactions, too

Other methods of olefin hypochlontes production, in the effort of restraining the chlorinated by-products formation, employ a tert-alkylhypochoπte as the hypochloration agent /10, 11 , 1 , 12, 13/, similarly /4, 14/ describe the reaction process of hypochlorous acid (HOCI) with olefins in presence of water-saturated organic solvents, e g lower alkylketones, lower alkylesters, acids, etc But these methods are disadvantageous as the tertiary alcohol, which is to extract the HOCI reacts with it, as well, producing the respective alcoholates Therefore the extraction of HOCI in presence of alcohols leads to obtaining a broader scale of the reaction byproducts The process then requires an addition of consecutive separation steps next to the reaction one

The greatest portion of the by-products formed herein represent dichloπdes, formed as a result of inadequate mixing and homogenization of the reaction mixture in the individual reaction steps and subsequently of formation and accumulation of the third phase in the reaction system, where the undesired reactions proceed preferably afterwards. The next by-product is formed in consecutive reactions of alkylenechlorohyrin (ACH) on rising the residence time of the product in the reaction system.

References cited

[I] US 4 008 133 [2] GB 2 029 821 [3] DE 2 022 819 [4] US 3 845 145 [5] DD 298 774 [6] CA 66:46 315 [7] CA 79:54 263 [8] US 4 496 777 [9] JP 45-4042 [10] GB 2 277 085

[I I] GB 2 264 493 [12] US 4 126 526 [13] US 4 443 620 [14] US 3 718 598

Summary of the invention

This invention describes device for chemical technology applications, suitable for systems, where the reaction rate is limited by diffusion, or for systems with coexistence of several phases: gas / liquid (g/l), gas / liquid / liquid (g/l/l), gas / liquid /solid (g/l/s).

The embodiments of this invention comprise a reactor of gaslift type (the only source of energy is the gas expansion, which dissipates in the upward movement of the liquid/gas dispersion in the reactor) with internal circulation of the reaction medium, with continuous feed of the starting materials and discharge of the product, and its use in e.g. process of production of epoxy-compounds via the corresponding chlorohydrins, in particular, it relates to the step of alkylenechlorohydrin (ACH) production in the reaction of gaseous chlorine, water and olefin.

The constructional solution of the reactor enables high yield of the desired product achievement and suppression of by-products formation.

The device has a shape of two concentric vertical cylinders, inside of which the liquid circulates as a result of difference in density of the fluid at a given time present in riser (the inner cylinder, bubble section) and down-comer (the outer cylinder, recycling section) of the reactor.

The material outfit of the reactor components is designed to withstand acidic medium with oxidative properties.

Gaseous substances are continuously fed into the reactor, the reaction takes place in aqueous solution of product which is of chlorinated hydrocarbons origin, wherein the formation of various intermediates occurs in sequence of reaction steps along the corresponding reaction zones. This brings about varying requirements on material and construction resistance of the individual reactor parts. The individual sections and other components of the reactor are therefore made of various materials, such as: glass, titanium, polyvinylidenefluoride, PTFE, etc., wherein the specific component requirements in terms of its chemical and constructional resistance and endurance are taken into account.

Height of the reactor is from 2 to 12 m, ratio of down-comer and riser areas ranges from 0.9 up to 2.9, ratio of the reactor height and width from 3 up to 50. Flanges of the individual riser and down-comer sections are located in the same heights and joined mutually.

The upper part of the reactor is designed and functions as separator. It comprises a section, which is formed by widening the down-comer of 3/5 up to 3/4 of its original diameter, wherein the changeover passage between the original and the widened zone of the down-comer is designed conically. Outlet of the product solution also emerges from this zone. Flanged- gas discharge piping is located on the lid of the reactor. Inner section of the separator is formed by the part of the riser, which extends up to the first half of the height of the widened down-comer section. For purposes of the process effectiveness observing the separator is equipped with two observation holes at the opposite sides of the separator. The height of the down- comer5 section of the reactor is from 1/2 to 3/5 of the riser4 height. The height of the liquid level in the reactor is adjustable and is maintained by a regulation device placed on the separator lid.

In the longitudinal section of the riser there are two distinct reaction zones, where ordinarily is a structured packing of static mixers type loaded in segments. The number of the packing segments, or more generally speaking, the actual packing height, in the individual zones is variable and dictated by the system behaviour. Under each of these sections there usually is a support grid with a gas distributor.

The construction of the riser3 and down-comer3 section enables, with respect to the high demands on its material resistance, changing the type of the distributor used.

To the bottom part of the riserl section a reaction component is introduced through a jet nozzle. In the top part of this section there is a distributor, which usually is, from the material and construction point of view, designed differently from the distributor. In the space below the distributorl , there are circular openings round the body of the riserl . These openings allow the circulating liquid to be sucked in from the down-comer into the riser. The total area of the openings is minimally 90% of the riser cross-sectional area, whereupon the size of the openings rises gradually in the downward direction.

A part of the down-comer is equipped with heating/cooling jacket.

The reaction mixture composition and concentration indication is based on measurement of redox-potential values after each of the reaction zones.

The third phase is withdrawn through the C and E valves at the bottom of the reactor. There's a sampling valve in the riser3 section.

The reaction mixture temperature is checked after each of the reaction zones, in the riser3 section and on the lid of the separator.

The reactor design introduced herein enables to intensify the contact of reaction phases in the corresponding reaction steps, or/and effective separation of the individual phases shortly after their formation. It is also obvious that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts without departing from the spirit of the invention.

Brief description of the drawing D5 separator, part of down-comer (part of the outer cylinder)

D4 section, part of down-comer (part of the outer cylinder)

D3 section, part of down-comer (part of the outer cylinder)

D2 section, part of down-comer (part of the outer cylinder)

D1 section, part of down-comer (part of the outer cylinder)

R5 inner section of separator, part of riser (part of the inner cylinder)

R4 reaction zone, part of riser (part of the inner cylinder)

R3 section, part of riser (part of the inner cylinder)

R2 reaction zone, part of riser (part of the inner cylinder)

R1 section, part of riser (part of the inner cylinder)

P flange

S distributor

O gas discharge piping

K product solution discharge

A gaseous reagent inlet

B liquid reagent inlet

C discharge of third phase from riser (inner cylinder)

E discharge of third phase from down-comer (outer cylinder)

Example

A gaseous olefin - propylene is introduced in the reactor through distributor (S2), gaseous chlorine through distributor (S1 ) and water through the nozzle (B). Hypochlorination of propylene (PR) occurs to produce propylenechlorohydrin (PCH). The reactor operates at loading conditions of the lower, chlorine zone (R2) 324 gCI₂/dm³zone/h and the upper, propylene zone (R4) of 652.5 gPR/dm³zone/h, whereupon the molar ratio of the gases introduced is PR : Cl₂ = 2 : 1 , the water is introduced in the amount that corresponds to the discharge of 4730 g/h 5 % (by mass) of aqueous solution of the product. At a pressure slightly above atmospheric and temperature of 30deg.C, the selectivity reached the steady-state value of above 94% at practically total chlorine conversion.

There are three coexisting phases in the reactor: gas / liquid / liquid (g/l/l).

Industrial use

This device is suitable for systems of chemical technology, where the reaction rate is limited by diffusion, or for systems with coexistence of several phases: gas / liquid (g/l), gas / liquid / liquid (g/l/l), gas / liquid /solid (g/l/s).

Claims

C L A I M S

1. Device that has a shape of two concentric vertical cylinders that can be used in chemical technologies, is suitable for systems with coexistence of several phases: gas / liquid (g/l), gas / liquid / liquid (g/l/l), gas / liquid /solid (g/l/s), where the only source of energy is a gas expansion and which is characterized in that its height is from 2 to 12 m, ratio of the outer (D) and inner (R) cylinder areas range from 0.9 up to 2.9, ratio of height and width of the inner cylinder (R) is from 3 up to 50, wherein the liquid circulates inside as a result of difference in density of the fluid at a given time present in the inner (R) and the outer (D) cylinder of the device, wherein the outer section of separator (D5), which comprises the product outlet (K), observation holes located in the opposite walls and the gas discharge piping (O) on the lid, has a part formed by widening the outer cylinder of 3/5 up to 3/4 of its original diameter, wherein the separator (D5) height is from 1/2 to 3/5 of the (R4) reaction zone height, wherein the inner section of the separator (R5) is formed by the top part of the inner cylinder, which extends up to the first half of the widened part of the outer cylinder height, wherein the longitudinal section of the inner cylinder comprises at least one reaction zone (R2, R4), therewith corresponding number of the related sections (R3, R1 ) and the inner part of the separator (R5), wherein the reaction zones (R2, R4) ordinarily contain a packing loaded in segments on a support grid wherein the related sections (R3, R1 ) comprise a gas distributor (S2, S1 ), wherein the section (R1 ) contains a jet nozzle at the bottom for a liquid reagent introduction, valves (E,C) for the third phase withdrawal and gas distributor (S) in its upper part, wherein below the distributor (S1 ), there are circular openings round the body of the inner cylinder that allow the circulating liquid to be sucked in from the outer (D) into the inner (R1 ) cylinder. wherein the total area of the openings is minimally 90% of the riser cross- sectional area and the size of the openings rises gradually in the downward direction, wherein a part of the outer cylinder (D1) is equipped with heating/cooling jacket, wherein a sampling valve is in the (R3) section, wherein the sections are made of various materials, mainly glass, titanium, PVDF, PTFE.

2. Device of claim 1 which is characterized in that it enables reactions of hypochlorination of olefinically unsaturated compounds introduced in gaseous state with gaseous chlorine and water to be carried out in aqueous solution of the product, wherein the olefinically unsaturated compound is either branched, linear or cyclic olefin, which contains from 2 to 6 carbon atoms, wherein the dissolution and hydrolysis of chlorine take place in the chlorine zone (R2) of the inner cylinder (R) and the reaction of the dissolved chlorine with the olefin introduced in gaseous state occur in olefin zone (R4) of the inner cylinder (R) wherein the amount of water introduced is to guarantee a constant outlet product concentration from 5 to 11 % by mass, wherein the amount of gaseous chlorine is such that its mass fraction at the end of the chlorine zone (R2) is 0,001 as a maximum, wherein the operation pressure is from 1 to 2 atm. above the solution level in the device, wherein the operation temperature is from 20 to 90deg.C.