DE1187587B - Device for heat and mass transfer - Google Patents

Description

Device for heat and mass transfer The invention relates to a Device for heat and mass transfer between liquids and gases or vapors using a heating or circulating in a heatable or coolable housing Cooling drum, which is immersed in a liquid sump located in the housing and is covered with a thin layer of liquid as it rotates.

In the known devices of this type, evaporation takes place of fluids from a stagnant swamp. The evaporation process of the Drum surface is entrained liquid film with a single rotation the drum finished; the residue or the dried layer is removed from the drum scraped off.

It has now been found that a gradual enrichment of the liquid as well as the steam at defined sufficient. long exchange time can be achieved, if the housing according to the invention on both end faces with inlets and outlets for the liquid sump flowing continuously in the axial direction over the housing base and above the sump with inlets and outlets for also in the axial direction the space formed between the film-bearing drum surface and the housing wall in Co-current or counter-current sweeping gases or vapors is provided.

There is an axial flow direction of the liquids to the rotating drum and gases are forced, changes in concentration result over the length of the rotating drum the liquid and the gases or vapors, whereby the respective partial concentrations of the film carried along on the drum surface in the direction of flow of the sump steadily increase. So there is a summation of in the axial flow direction local partial concentrations of the film taking place. The speed the drum is arbitrary, but the length of the drum must be in relation to the throughput can be adjusted to the desired level of concentration.

The locally small changes in concentration in the circumferential direction the drum have the advantage of skinning and thermal overload the liquid to be treated is avoided with certainty. In addition, you can by means of the device as a result of the defined guidance of liquid and steam realize several theoretical separation stages in evaporation processes. To enlarge the liquid content and thus to increase the residence time of the liquid the housing is widened in the shape of a channel along the bottom.

In order to increase the area of the liquid film exposed to the treatment than doubling the size, the housing is rotatable in the opposite direction to the drum arranged. This also makes the mixing effect in the liquid flow perpendicular to whose direction of flow is significantly increased. It can be useful for certain substances be the boundary surfaces of the drum and housing that support the liquid film to roughen up.

The device is for degassing, deodorizing, or vaporizing Condensation, for carrying out reactions in liquid gas form and also as pressure low-loss rectification column useful. For reactions with strong warming can reduce the heat of reaction as a result of extensive distribution of the liquid in thinner Layer are supplied or removed with great advantage.

Exemplary embodiments of the subject matter of the invention are shown in the drawing shown schematically.

From b. 1 shows a longitudinal section through a device according to FIG Invention in which only the roller rotates and the outer tube is fixed; From b. 2 is a cross section through this apparatus; A b b. 3 illustrates a cross section by means of a device in which the pipe and roller form the boundary surfaces of the annular gap form, rotate in opposite directions to each other, both through a liquid film be wetted; Fig. 4 shows the cross section through an apparatus in which on the A channel-shaped extension is provided on the underside of the outer tube.

According to Section 1, an embodiment of the device consists of an elongated horizontal Right lying pipe 1. At one end of the pipe 1, the liquid to be treated is fed through the nozzle 2. In the tube 1 only so much liquid is accumulated that only the lower part of the pipe is filled with liquid. The liquid can be at the other end of the Run off the pipe 1 through the nozzle 4. Depending on the viscosity and the desired throughput the liquid can be the tube 1 z. B. in the m7mkelR inclined to the horizontal be.

Inside the tube 1, a roller 5 is rotatable in the bearings 6 and 7 arranged. The roller 5 can be heated or cooled and is set in slow rotation. It dips alongside in the liquid flow 3 and increases as it rotates a thin liquid film 8, the thickness of which depends, among other things, on the circumferential speed the roller and the viscosity of the liquid. The flow of liquid 3 is mixed in direction 16 by the movement of the roller. Above the Liquid flow 3 is located between the inner wall of the tube and the with the liquid film 8 covered roller 5 a gap 9 through which gases or vapors be guided in cocurrent or countercurrent to the liquid flow 3. The in and Outlet nozzles for the gases or vapors are denoted by 10 and 11. The pipe 1 is provided with a jacket 12 with inlets and outlets 13, 14 for heating or Coolant is equipped. Since the liquid in the form of a sticking on the roller 5 Film transported through the space 9 traversed by the gases or vapors there is no mixing of the liquid with the gases or vapors, so that even liquids that tend to foam can be treated completely foam-free permit.

Another advantage of the apparatus is that the residence time of the liquid with constant liquid content of the apparatus with the throughput arbitrarily - in borderline cases with zero passage, possibly infinitely - set can be without affecting the thin layer distribution of the liquid. In the case of a finite passage, the liquid becomes depending on the circumferential speed of the roller constantly circulated by a multiple of the throughput in a thin layer and the desired one Treatment gest; Because the movement of the roller is perpendicular to the direction of flow of the liquid trough takes place in the tube, there is practically no mixing in the axial direction, so that there is a very good residence time spectrum.

The arrangement can therefore be combined with a large number of Ideally mixed stirred tank with a large specific liquid surface (order of magnitude 1 m² / l).

By rotating the tube in the opposite direction at the same time becomes a rotating roller, as in A b b. 3 shown the liquid not just on it the roller, but also on the inner surface of the pipe in a thin layer 15 distributed, whereby the liquid surface exposed to the treatment to more than is magnified twice. At the same time, there is the mixing effect in the liquid flow perpendicular to the direction of flow, (see arrow 16) significantly reinforced. To guarantee In order to ensure good wetting, it is advisable to roughen the roller and the inner surface of the pipe (e.g. by sandblasting).

Furthermore, the tube has to increase the liquid content 1, as Fig. 4 shows, a channel-shaped extension 17 on the underside.

Claims (3)

Claims: 1. Device for heat or mass transfer between Liquids and gases resp. Steam using one in a horizontal or to the horizontal inclined heatable or coolable housing revolving heatable or coolable drum, which is immersed in a liquid sump located in the housing and during its rotation is covered with a thin layer of liquid, which means that it is not displayed e t that the housing on both ends with inlets and outlets for the continuous in the axial direction flowing through liquid sump and above the sump with Inlets and outlets for the film-bearing drum surface, also in an axial direction and housing wall formed space in cocurrent or countercurrent flow through gases or fumes are present. 2. Apparatus according to claim 1, characterized in that the housing is widened channel-shaped along the bottom. 3. Apparatus according to claim 1, characterized in that the housing is rotatable in the opposite direction to the drum. Considered publications: German Patent Specifications No. 207 152, 219 259, 612 756; British Patent No. 163,793.