CS212250B2 - Appliance for executing the exothermic and endothermic processes - Google Patents

Abstract

1. Apparatus for admitting heating energy or abstracting reaction heat during the polymerisation of monomers, especially during the suspension polymerization of vinyl chloride, consisting of a cylindrical container provided with baffle plates, with at least one multiple blade mixer and, at its inside wall, with a heat exchanging structural component in the form of a peripheral semitubular coil characterized in that within the cylindrical portion of the container (1) the semitubular coil (4) is formed of adjoining semitubular windings, the semitubular windings being semicircular tubes.

Description

BACKGROUND OF THE INVENTION The present invention relates to an apparatus for carrying out exothermic and eodothermic processes by indirect cooling or heating by means of a cooling or heating medium, comprising a reactor provided with turbulent elements, in which a mill-bladed stirrer is arranged and heat exchange structures are arranged on the inner wall.

Temperature-controlled reactors are used for supplying and dissipating heat and, where appropriate, simultaneously mixing chemically reacting liquids or solid particles, which are particularly advantageous in terms of removal of build-up of deposits. The rectors can be cooled or heated by means of an outer jacket, whereby the heat transfer can be improved several times by scaling the reactor. The reactor jacket may consist of a welded helix of a tube with a semi-krihi profile or of an angular profile - see Ulmanns Enzyklopadie der techoischeo Chemie, 4th ed., Volume 2, 1972, pp. 439 and 440.

In order to carry out polymerizations, for example suspension or block polymerizations in bulk, autoclaves are used, the temperature in the autoclave being kept at an optimum value by dissipating the polymerization heat. The heat is dissipated in this case by means of an autoclave wall which is provided with a double jacket through which the co-charge medium flows - see German patent application 2038363 and German patent application 2032700.

British Patent 1,453,614 discloses a cylindrical reactor suitable for carrying out chemical processes, which is sealed and provided with a cover through which the shaft passes

A heat exchange structure is provided on the inner wall of the reactor, which consists of a series of axially oriented hollow ribs, which are welded to the inner wall of the reactor on small surfaces. The upper and lower ends of the hollow fins are closed to the interior of the reactor, but are connected to the upper and lower annular chambers, which are provided with an inlet and outlet for the inlet and outlet of the heating or cooling medium into the interior of the hollow fins.

German Patent Application 2,326,704 discloses a heat exchanger for heating liquid soap, which consists of a cylindrical sleeve with a funnel-shaped dome and a conical cover, with a plurality of tubes arranged inside the sleeve with an internal combustion chamber therein. The tube assembly consists of a long tube coiled into a solid spiral. The threads and the threads of each other form a wall which, over the entire height, covers the inner wall of the housing and, in addition, part of the doo and hatch. Spacers are arranged between the wall and the inner side of the housing. A central bore for receiving the burner is provided in the housing. At least one smoke pipe is provided in the coiled pipe system, which is connected to the combustion chamber and the exhaust chamber, which is arranged on the outside of the housing, after half the thread of the pipe.

The disadvantage of these solutions is the heating and cooling of the large reactor through its wall, since in this case the ratio of the wall area to the reactor volume is particularly unfavorable, resulting in low specific reactor power by a unit of time and volume. In addition, when increasing the reactors, especially the tic reactors, the strength of the reactor must be increased excessively, which further reduces the specific heat transfer per unit area. The warm surface can be increased by the installation of cooling coils! but these built-in structures, which are generally technically complex, adversely affect the mixing and flow efficiency of the reactor, and the cleaning of a reactor equipped with such built-in structures, which is often required in reactor deposition processes such as polymer. It is usually only possible after these built-in con- trolctions are possible. A further disadvantage is that the built-in constructions always produce flow-free corners, in which deposits are formed very intensively, which cause heat transfer and, in particular in the case of a polymer, the fragments are released which reduce the quality of the product.

The above-mentioned drawbacks are eliminated by an apparatus for carrying out exothermal and end-to-end processes by indirect cooling or heating by means of a cooling or heating medium, consisting of a reactor equipped with turbulent elements in which a multi-blade stirrer is mounted and on which. The inner sheaths are constructed in accordance with the invention in that the heat exchanger structures are formed by radially tightly wound beams which are fixed to the inner wall of the reactor.

Heat exchange structures consist of semi-circular or corrugated tubes. chem, or angular prooils.

The control device is also provided with a control device which allows a continuous adaptation of the pressure of the cooling or heating material in the space between the inner wall of the reactor with the heat exchange structures according to the internal pressure.

A new and higher effect of the invention is that the solution according to the invention achieves an increase in the transfer area between the cooling or heating medium and the reactor contents.

The pressure of the cooling or heating milling in the space between the reactor wall and the heat exchange structure arranged thereon can be continuously adjusted to the pressure at the reactor. The strength of the heat exchanger structure can therefore be in this case even at high pressures inside the reactor, so that a low throughput thermal resistance can be maintained.

The heat transfer surface area of the reactor used in the process of the invention is up to 57% greater than that of a smooth reactor wall. In addition, due to the favorable flow in the reactor, it further improves the heat transfer through the wall and suppresses the formation of solid solids on the wall.

In the device according to the invention, a small wall thickness of the heat exchange structures can be used, since the mechanical strength is ensured by the wall of the reactor. The MalV wall thickness significantly improves the heat transfer. In this ^^ vesces! it should be pointed out that the reactor of mV withstand pressure such as ^1, 7 must have ^the s increasing volume thicker wall thus a volume of ²⁵ m ^3, from ^p ovídV wall thickness of 17 mm, a volume of 100 m ^3, thickness 25 mm and volume of 200 m ³ force 38 there, while the wall thickness of the sealed structure in the device according to the invention is in all cases only 3 min. FIG. 2 shows the dependence of the heat output on the reactor volume. The curve 6 here applies to reactors of the new construction, while the curve a applies to the apparatus according to the invention.

In the device according to the invention, dead corners are used without flow and can be easily removed manually or by means of pressurized water, without prior removal of the heat exchanger structures inside the reactor.

When using the apparatus according to the invention for the polymerization of monomers, the heating time can be considerably reduced at the same heating temperature and the lower heating temperature can be used at the same heating time. In intermittent suspension polymerization, for example in the production of polyvinyl chloride, this can limit the polymerization on the wall and thus increase the quality of the product by reducing the amount of impurities in the product.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is illustrated by way of example with reference to the accompanying drawings, in which: FIG. 1 shows a cross-sectional view of the device according to the invention; and FIG.

In the reactor 6 shown in FIG. 1, turbulence elements 3 are provided on the cylindrical walls of the reactor. A multi-blade stirrer 2 is mounted in the lower part of the reactor 6, the shaft of which passes through the bottom of the reactor. On the cylindrical wall of the reactor 6, the heat exchanger structure 8 is formed by a tightly wound screw from a tube with a cross-section which is welded to the cylindrical wall of the reactor. The heat exchanger structure 6 is provided with an inlet connection 6 and a two-way connection 6 for supplying and discharging heating or cooling

The advantage of the device according to the invention results from the following examples of its use.

EXAMPLE 1 Vertical _ ^p weaned cylindrical reactor with a volume of ^{25 U} rn instructed at a pressure of 1.7 WPA and provided with a stirrer and Sroubcove! from a tube of semicircular cross section welded to its outer wall — see Ullmanns Enzyklopadie der technischen Ctiemie '*, 4th edition, Volume 2, p. 439, Fig. 16D - was charged with 24 m ^J of 20 ° C water. After the stirrer was turned on, hot water at 95 ° C was supplied to the helix. Time oJhábí water in a reactor at 55 ° C was 36 Mnooitví temp ^AP řivád Joint for unity ^of NO ^and dried. was 63 x W ^P kW.

Example 2

The reactor of ^{EXAMPLE 1 b CART} ice yl filled with water ²⁴ m ^{P y} Tepi about ⁵⁵ ° C. ^P to turn on the stirrer ^would la helically feeding ^of water at 20 ° C and was fed a saturated · steam at 120 ° C mnoitví 1400 kg / h, the artery and vein, the water in the reactor is constantly maintained at the ^heat-I 55 ° C . Mnn ttfí ^t ^ ep ^ ^l and áděného per unit time amounted to ^0, 9 ⁶² x 10 ^W · ^P k

Example ^{3, the} vein dently pos ^Al sunflower seed reactor of 5 m ^{2 P} designed for a pressure of 1.7 MPa and a stirrer and Sroubooicí from the tube in a semicircular cross section with a wall thickness of 3 mm welded to its Větrná :! ^te nu ^b yl charged ²⁴ m ^P in the ^{soil T} e ^^ about ^I 20 ° C. ^p stirrer was switched on to ^longitude duplexes fed with hot water at 95 ° C. The water heating time in the reactor at 55 ° C was 20 minutes. Mnnoití t ^ep la ^{p n Ri} ADE ého for j ^e dmstk ^at time ^u amounted to 2.97 ^{P χ} 10 kW, i.e. 182% mnoitví heat supplied in the known device of Example 1.

Example foedctor of ^EXAMPLE 3 ^CART ice ^b yl charged ²⁴ m ^{P y} of water at 55 ° C. ^p o zapiutí míchiadla la helically ^would be fed with water at 20 ° C and the reactor was fed with saturated steam at 120 ° C in mnoitví 2480 kg / h water CIMI reactor was constantly maintained at 55 ° C. The heat dissipation per unit time was 1.7 ° x 10 ^P kW ^, i.e. 177% of the heat dissipated by the known apparatus of Example 2.

Example 5

The Rector of Example 1 was filled with the following substances after the agitator was switched on:

partially water-soluble polyvinylacetate hydro-xylurylmyll eluate sodium ionate salt

800 kg

3J

2.6 kg kg

After air evacuation, 8,300 kg of ln-l-lhloride and 5 kg of bitodium (2-ethylhexyl) peroxydicarbonate with a 65% loading were added. By passing hot water at 95 ° C, the reactor content was allowed to reach 55 ° C in 29 minutes. Deň: 32 ° C. When the reaction temperature was reached, 20 ° C water was added to keep the reaction temperature constant.

After completion of the pollierization, the reactor pressure was reduced, the slurry was freed of the residual voyl chloride by tapping with water vapor, and the slurry was centrifuged from the slurry. Each hour, 995 kg of psilvimilchride was obtained.

The following tests were carried out to determine the quality of the polyvinyl chloride produced:

a) Determination of K value (according to DIN 53 726, published June 1961), result K = 70.

^(b) Determination of bulk density: ^{470 g} / dm ³

(c) Impurity test. A 0.2 mm thick film was made by rolling at a temperature of 40 ° C for 15 million. ⁵ were examined ^four film samples of the surface of ¹⁰⁰ cm ^2, the average ^{number p} of impurities,

of these five mixtures, 12 impurities per 100 cm.

The reactor was finally cleaned with 25 mPa.s water. the purification water was filtered and approximately 0.5 kg of solid waste resulting from the deposition on the reactor walls was detected.

Example 6

In the reactor of Example 3, all four of the compounds of Example 5 were introduced with constant stirring. peroxodicarbonate with a kenceeitoation of ⁶⁵ %. The reactor contents were passed through water at 95 ° ^C or oleate at ¹⁴ ° ^C for ¹⁴ minutes at a reaction temperature of ⁵⁵ ° C. ^p o ^u tte ⁱ en: ^reaction temperatures being in Dreams in oubooi.cí ^ ^u ^ te OTE and ²⁰ b ^y the reaction ^'to maintain the temperature onstahtní.

After completion of the polymerization, the procedure of Example 5 was continued. Every hour, 1,250 kg of polyvinyl chloride, i.e. 126% of the weight produced by the known paddle apparatus of Example 5, was recovered. deposit on the reactor walls.

To verify the quality of the polyvinyl chloride produced, the same tests as in Example 5 were performed, with the following results:

a) the value of K = 70, ^{b) y} PNA hmstoost 475 g / d and ^ ^{3 c)} 5 to ¹⁰⁰ cm nečtotot ^{2 f} olie.

Claims (5)

OBJECT OF THE INVENTION An apparatus for carrying out exothermic and endothermic processes by indirect cooling or heating by means of a cooling or heating medium consisting of a turbulent element reactor, in which a stirrer stirrer is arranged and on whose inner wall heat exchange structures are arranged , ^wherein the znnlující TiN tepossměnné that the structure (4) are formed by radial tightly wound because that welds are attached to the inner wall of the reactor (1). _k . 2. Apparatus according to claim 1, characterized in that the heat exchange structures (4) consist of tubes of semicircular cross section. 3. Apparatus according to claim 1, characterized in that the heat exchange structures (4) consist of corrugated sheet. 4. Device according to claim 1, characterized in that the heat exchange structures (4) are formed by angular profiles. Apparatus according to claim 1, characterized in that it is provided with a control device which permits a continuous adaptation of the pressure of the cooling or heating medium in the space between the inner wall of the reactor (1) and the heat exchange structures (4) according to the pressure inside the reactor (1).