FR2583652A1 - IMPROVEMENT TO THE COOLING TOWERS OF DUSTING GASES - Google Patents

Abstract

DUST-LOADED GAS COOLING TOWER EQUIPPED WITH A SUPPLY DUCT 16 FOR THE SUPPLY OF THE GAS TO BE TREATED CONNECTED TO THE TOP OF THE TOWER BY A TRUNCONIC DIFFUSER 12 AND WITH WATER SPRAYING NOZZLES PLACED IN THE UPPER PART OF THE TOWER TOWER. TO IMPROVE THE GAS DISTRIBUTION IN A STRAIGHT SECTION OF THE TOWER, A REVOLUTION BODY 20 THE DIAMETER OF WHICH IS GRADUALLY GROWING IN THE DIRECTION OF THE GAS FLOW IS PLACED IN THE DIFFUSER 12, PREFERABLY IN ITS UPPER PART, TO SHAPE WITH THE WALL OF THIS LAST A PASSAGE WITH DIVERGENT ANNULAR SECTION.

Description

The present invention relates to cooling towers for cooling

  dust-laden gases, in particular

  fumes, which consist of a vertical chamber

  wedge, A circular section, and are provided with a supply duct for the supply of gases To be treated At a

  end of the tower, spray nozzles

  at the same end of the tower to inject a

  liquid, usually water, in finely divided form

  seized in the gas stream and an exhaust duct

  for the gases treated at the other end of the tower.

  These towers are used, in particular, for

  treat fumes before they are

  to bring their temperature and / or their

  moisture content at values that allow

optimum performance of the dust collector.

  One of the problems that must be solved in the design and operation of these towers is that of the uniform distribution of water droplets in the gases. This problem is largely due to the fact that the speed of the gases is not constant throughout

  section of the tower, at the level of the spray nozzles.

  The uneven distribution of speeds is essen-

  the fact that the supply duct has a section much smaller than that of the tower and makes

  an angle generally close to 90 with the axis of the tower.

  To remedy the first defect, the duct is connected to the tower by a frustoconical diffuser, but this solution is imperfect and the gas velocity along the walls of the tower always remains lower than the speed in the tower.

  the axis of the tower. The change of direction which is impor-

  When flowing from the supply duct into the tower or into the diffuser, the effect of the gases is to create an asymmetric distribution of the velocities which have been sought

  To correct by placing in the elbow connecting the con-

  tower a series of curved deflectors dividing the gas into several elemental veins. This solution has not proved very effective either. In addition, the detachments that occur along the wall with the appearance of return currents promote the projection of the droplets on the wall with the risk of corrosion of the latter. The object of the present invention is to improve the distribution of gases in a straight section of the tower, in particular by increasing the speed of the gases along the

walls of the tower.

  The cooling tower which is the subject of the present invention is characterized in that it comprises, in a manner known per se, a frustoconical diffuser placed at one end of the tower, coaxially with it and in that a body of revolution of which the diameter increases in the direction of gas flow is placed in the diffuser, in the axis thereof and preferably

  in its narrowed part, so as to form with the

  king of the diffuser a diverging passage with annular straight section. This body may be closed at its upstream end and constituted, for example, by a cone. It can also be hollow and open at both ends. In

  the latter case, several bodies of revolution with diameters

  progressively increasing in the flow direction of the gas can be arranged concentrically in the upper part of the diffuser; we can, for example,

  provide several concentric cone trunks.

  The body of revolution may be supported by several radial vanes fixed to the wall of the diffuser; these blades are preferably profiled and arranged vertically or slightly inclined relative to the vertical.

  The following description refers to the drawings

  which show, by way of nonlimiting example, two embodiments of the invention and in which: FIG. 1 is a view, in elevation and in section, of the upper part of a cooling tower -3- carried out according to the invention; and FIG. 2 is a partial view, in elevation and

  in section, of another embodiment of the invention.

  In Figure 1 there is shown the upper part of a cooling tower 10 which is connected by a frustoconical diffuser 12 and a bend 14 to a gas supply line to be treated 16. The vertical portion of the bend is slightly convergent of so that it forms with the diffuser-12 a venturi whose neck is located in their connection plane 18. A cone 20 is placed in the upper part of the diffuser, below the plane 18. This cone which is sheet metal can to be closed or open at its base. It is supported by radial vanes 22 fixed to the cone and the diffuser. These vanes have, in cross-section, a streamlined shape in the direction of flow

  gases and their median plane is either vertical or

  tilted to communicate a slight movement of

rotation to the gas stream.

  Curved deflectors 26 are placed in the bend 14 and spray nozzles 28 are arranged in

the lower part of the diffuser.

  In the embodiment of Figure 2, the apex angle of the diffuser 12 is much larger than

  that of the diffuser of FIG. 1 and the cone 20 is replaced by

  placed by two concentric conical frustums 20 'and 20 "arranged coaxially in the diffuser, these two truncated cones forming, with the wall of the diffuser two passages

  concentric, annular section, and a central passage.

  The central cone frustum 20 "could be replaced by a cone, the spray nozzles 28 'are arranged in the upper part of the tower 10'.

  more than two concentric truncated cones may be provided.

  Although the above description refers to a

  tower with admission of gases to be treated from the top and

  evacuation of the gases treated from below, the invention is

  It also applies to the towers in which the gases are admitted at the bottom of the tower and discharged at its top, the spray nozzles being in this case in the

bottom of the tower.

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Claims (7)

R E V E N D I C A T I 0 N S   1. Tower cooling gas charged with dust,   including smoke, consisting of a vertical chamber   wedge, circular section and provided with a feed duct for supplying gases to be treated at one end of the tower and water spray nozzles placed   at the same end of the tower, the   tation is connected to the tower by a truncated diffuser   placed at the same end of the tower, coaxially with it, characterized in that a revolution body (20, 20 ', 20 ") whose diameter increases progressively   in the direction of gas flow is placed in the   (12, 12 ') in the axis of the latter and preferably in its narrowed portion, so as to form with the wall   of the diffuser a passage with annular section divergent.   Cooling tower according to claim 1, characterized in that said body of revolution (20) is closed at its upstream end.   Cooling tower according to claim 2, characterized in that said body is constituted by   a cone (20) whose tip is directed upstream.   4. Cooling tower according to claim 1, characterized in that said body of revolution (20th)   is open at both ends.   Cooling tower according to claim 4,   characterized in that said body (20 ') is truncated   than. Cooling tower according to claim 4 or 5, characterized in that several bodies of revolution   (20 ', 20 ") are concentrically placed in the diffuser.   - 6 - 7. Cooling tower according to any one of   preceding claims, characterized in that said   body of revolution is supported by fixed vanes (22)   the wall of the diffuser and the median plane of which is   tilted from the vertical.