Reactors of this type are used for various purposes.

For instance, they can be used for cleaning of process gases containing gaseous pollutants, and for cooling/ heating of gases. In these two applications, it seems possible to improve the efficiency of the reactor, i.e.

increase the capacity of the reactor of respectively cleaning and cooling/heating the gases.

The object of the present invention therefore is to provide an open contact reactor, which has an improv- ed efficiency in relation to prior-art reactors.

According to the invention, this object is achieved by an open contact reactor, which is of the type describ- ed by way of introduction and which is characterised in that a gas guiding means, which extends along the cir- cumference of the tank and is adapted to guide the gas flow closest to the wall of the tank towards the interior of the tank essentially perpendicular to the main gas flow direction, is arranged between the levels in at least one pair of juxtaposed nozzle levels, the guiding means extending into the tank to a distance from the wall thereof, which over the major part of the circumference of the wall at each point is 10-90° of the distance between the nozzle positioned closest to the respective point and the wall.

A gas guiding means preferably is arranged between the levels in each pair of juxtaposed nozzle levels.

The invention will now be described in more detail with reference to the accompanying drawing, in which: Fig. 1 is a schematic vertical sectional view and illustrates a portion of an open contact reactor accord- ing to the invention, and Fig. 2 is a schematic cross-sectional view along line Il-Il in Fig. 1.

The open contact reactor shown in the drawing is in the form of an upright, essentially circular-cylindri- cal tank 1, of which merely a portion is illustrated in Fig. 1.

A plurality of spray nozzles 2 for spraying fine- ly divided liquid are arranged in the tank 1. The spray nozzles 2 are arranged on a plurality of vertically spaced-apart levels L1, L2, L3, the nozzles on each level being uniformly distributed over the cross-section of the tank 1, except in the portion positioned closest to the circumference of the tank 1, in which portion there are no spray nozzles and/or parts of spray nozzles that would imply a uniform distribution over the entire cross-sec- tion. Each nozzle 2 has a circumferential, conical spray action, by which is here meant that it sprays liquid essentially uniformly distributed over an intended cone or an intended truncated cone.

In the embodiment shown, the spray action of the nozzles 2 is directed downwards. However, it will be appreciated that their spray action can also be direct- ed upwards or be directed both upwards and downwards.

In the embodiment shown, the reactor is used for cleaning process gases containing gaseous pollutants.

The process gases are conducted essentially vertically through the tank 1 in the direction of the arrows P in order to be contacted with the finely divided liquid.

In other applications, the process gases can be conduct- ed through the tank 1 in the direction opposite to the

direction of arrows P. In this embodiment, the liquid consists of water and an absorbent dissolved or suspend- ed therein, which reacts with the gaseous pollutants in the process gases.

Between the levels in each pair of juxtaposed levels L1, L2, L3 there is arranged a circumferential gas guid- ing means 3, which extends along the circumference of the tank 1. The gas guiding means 3 are adapted to guide the gas flow closest to the wall of the tank 1 towards the centre axis of the tank essentially perpendicular thereto and, thus, essentially perpendicular to the main gas flow direction P.

Each gas guiding means 3 has the form of a simple, circumferential horizontal flange, but, for guiding the gas flow towards the centre axis of the container 1, it may also have another form which is suitable for the purpose. For instance, the gas guiding means 3 can be arcuate in cross-section, but it may also have a more complicated shape and consist of, for instance, a series of bucket-shaped gas guiding elements which are juxtapos- ed along the circumference of the tank 1. The gas guiding means 3 functions to some extent also as liquid guiding means by the gas flow guided towards the centre axis of the tank 1 entraining liquid which is collected on the wall of the tank 1.

In the illustrated embodiment, the gas guiding means 3 extends into the tank 1 to a distance from the wall thereof, which distance over the major part of the cir- cumference of the wall at each point corresponds to about 50% of the distance between the nozzle 2 positioned closest to the respective point and the wall. As shown in the drawing, this means in the embodiment shown that the circumferential horizontal flange has a horizontal width varying along the circumference. Said distance of the gas guiding means 3 may, however, vary between 10 and 90% of said nozzle distance and preferably is between 30 and 65%.

The arrangement of the gas guiding means 3 has been found to increase the efficiency of the reactor in a favourable manner.