FR2471203A1 - MULTI-STAGE EVAPORATION METHOD AND DEVICE - Google Patents

Abstract

A. THE PROCESS AND THE DEVICE ARE INTENDED TO OBTAIN MIXED CONDENSATION IN MULTI-STAGE INSTALLATIONS FOR CONCENTRATING RADIOACTIVE CONTAMINATED SOLUTIONS OR SUSPENSIONS. B. WE USE TO ENSURE CONDENSATION, FROM THE SECOND STAGE OF AN INJECTOR OR A JET PUMP 10. C. THIS PROCESS ALLOWS TO CONSIDERABLY REDUCE THE DIMENSION OF THE EQUIPMENT NECESSARY FOR THE CONDENSATION.

Description

-2471203

  1. The invention relates to a method and a device for condensation in a mixture in installations

  multi-stage evaporation, for the concentration of -

  solutions containing salts and / or suspensions of solids, in particular for the decontamination of solutions and sus-

  pensions to radioactive contamination.

  In multi-stage evaporation plants, the hot vapors of the previous evaporation stage can be liquefied by up-stage cocondensation.

  following evaporation. The heat transferred during the co-

  condensation is exploited by reducing the pressure

  above the liquid being in forced circulation, for a

new evaporation.

  According to German Offenlegungsschrift No. 2,418,045, hot vapors are introduced into the liquid through perforated or other surfaces. The disadvantage here is that the mixing condensers of this type are of a cost-effective design, that the perforated surfaces are easily clogged, cause water hammers and require extensive monitoring. When dealing with contaminated radioactive suspension solutions

  these disadvantages can cause particular difficulties.

  A method described in DE-OS 2,632,910 employs indirect heat exchangers for each stage. This procedure is technically expensive,

  expensive, and has particular surveillance problems.

  adverse effects of radioactive wastewater.

  Accordingly, it is an object of the invention to provide a method and apparatus for condensation in a multi-stage evaporation plant for the concentration of solutions containing salts and / or suspensions of solids, particular for the decontamination of solutions and suspensions with radioactive contamination, as well as a device for the implementation of this method, which is above all easy to monitor, does not present too much

  technical requirements, and does not tend to clog.

  For this purpose the invention proposes that one implements for cocondensation, starting from the second

  floor, jet pumps or injectors.

  The invention will be better understood with the aid of the accompanying drawings showing an exemplary embodiment or 2.- - Figure I gives a particularly advantageous embodiment of the device according to the invention, Figure II is a representation.

detailed of an injector.

  The liquid to be evaporated is introduced by means of a tubular pipe 1 via a preheater

  3, in an evaporation tank 2 of the first stage of the evaporation

  tor. A recirculation pump 4 brings back the liquid again

  passing through the heat exchanger 5 and a choke screen

  6 Part of the liquid evaporates during the expansion of the circulating concentrate in the throttle diaphragm 6. The amount of heating vapor

  supplied to the heat exchanger 5 by a feed pipe

  tion 7, is decisive for the flow of the

  poration. In the evaporator vessel 2, the hot vapors are separated from the circulating concentrated liquid. The heat released from the condensation of the heating vapors flowing through a pipe 8, warms up in the preheater 3 the liquid that leads the pipe 1. The hot vapors of the first stage

  evaporation by a pipe 9, in a conden-

  mix 10, which is on the recirculation line

  11 of a second stage of evaporation. All gouttele-

  trained here by the vapors of the first stage of

  are injected into the concentrate circuit of the second:

  evaporation stage, and are incorporated into it, and thus the taste

  first floor let's not soil the distillate

  of the next stage, for example by radioactive contamination.

  This injection is effected by means of an injector 10 represented

  feeling a mixer condenser. Jet pumps, as small compact elements, are particularly suitable for

  incorporated, according to the invention, as melting condensers

  because they are practically a part of the

recirculation line.

  The volume of known bulky condensers known up to now, which amounted, for example, to an evaporation capacity of 6.5 t / h, to 7 m 7, is reduced in the embodiment of the invention. for the same flow, at 0.1 m3, the weight of the equipment being reduced to about 10% of the previous apparatuses. The condensation-and mixture according to the invention is carried out, in the example chosen,

3-2,447,203

  in an injector, having a theoretical dimension of about 300 mm

  and a length of about 1.5 m. We thus obtain a condensation

  complete steaming. The process according to the invention has also proved particularly advantageous with regard to

  ease of assembly, and ease of decontamination.

  nation, in the case of evaporation and decontamination of radioactive wastewater. Unlike known mixing condensers, multi-stage evaporator installations according to the invention can be started without water hammers detrimental to the apparatus. As a result, one can

  also give up the indirect heat exchangers-nec-

  until now ,. The jet injector 10 operating as a mixer condenser is mountable and dismountable and can be connected with the recirculation line 11 and the throttle diaphragm 17 of the second evaporation stage, as well as with

  the pipe 9 of the supply of vapors, by means of flanges 12.

  Between the injector 10 and the pipe 9, bringing the hot vapors

  A stop valve 13 is inserted. It is advantageous

  To provide other stop devices between the injector 10 and the detrangement diaphragm 17 adapted to the circuit, and the flow line 11. Thus the injector 10 can be exchanged quickly and safely. Due to the smallness of the outer surface it is advantageous to note only low heat losses. By the integration of the injector 10, representing the mixing capacitor in the circuit 11, the construction is simplified from the point view of thermal expansion. The second and optionally the other stages of evaporation, provided according to the invention each of a

  injector 10 functioning as a mixing capacitor, working

  slow according to the same principle as the first stage of evaporation, that is to say that the liquid returns, in forced circulation, the evaporation vessel 14, by means of the recirculation pump, to the injector 10. The vapors are heated by steam pipes 16, as the case may be, to the next stage, or

  has a subsequent reprocessing in the known manner.

  Concentrate of the first stage of evaporation

  is evacuated by line 18. The decantation of the second

  floor and the following is done by the pipes 19.

4.-

Claims (3)

  1. Process for condensation in a mixture in multistage evaporation plants for the concentration of solutions containing salts and / or   suspensions of solids, in particular for the decontamination of   nation of solutions and suspensions with radio-   active process, characterized in that for the condensation mixture, is implemented, from the second stage, injectors or jet pumps (.10).   2. A device for carrying out the process according to claim 1, constituted by a first evaporation stage comprising a preheater (3), evaporation vessel,   recirculation pump (4)., heat exchanger (5), a diaphragm   throttling (6), and one or more other stages of evapo-   with evaporation tank, recirculation pumps, throttle orifice, mixing lines and condensers,   characterized in that in the other stages of   poration, the mixing capacitors are constituted by injectors (10).   3.- Device according to claim 2, characterized in that the injector (10) communicates with the pipe (9) of hot vapors via a valve stop (13). : we