FI71067C - ENLIGTI PRINCIPEN FALLANDE FILM FUNGERANDE AVDUNSTNINGSENHET I ORM AV ETT LAONGT ROER OCH FOERFARANDE FOER INDUSTNING AV VETSKOR MEDELST NAEMNDA AVDUNSTNINGSENHET - Google Patents

Description

1 71067

A falling tube long tube evaporator unit and a method for evaporating liquids with this evaporator unit.

5 Long tube evaporation has been used for many years on the principle of a so-called blowing film. The structure according to Figure 1 is known from the product brochure APPAREILS et EVAPORATEURS KESTNER Lille 1976. and the structure according to Figure 2 from the same publication the product brochure APPAREILS et EVAPORATEURS KESTNER Lille 1976. In these known constructions, the liquid to be evaporated 102, 202 enters a separate liquid space 106, 206, where the liquid is distributed as evenly as possible by means of various known systems, usually perforated plates, the heat exchanger tube 1.1a 101, 201. The liquid flows as a falling film 15 along the inner wall of the tubes into the liquid / vapor space 104, 105, 204. The vapor generated by the boiling in the tubes 101 and the flowing liquid are separated in a separate separator section 1.05 or 204.

The difficulty of the known devices has been to evaporate liquids containing substances which "burn" or scorch on the surface of the pipe. In this case, the surface of the pipe becomes dirty and the pipe loses its ability to evaporate.

In addition, the pressure fluctuations p2 in the separator section during evaporation affect the liquid state 102, 202 via the tubes 25 101, 201. In this case, the pressure fluctuations prevent the liquid from flowing continuously from the liquid space to the separator space.

Too thin or discontinuous liquid film dries ("burns") to the inner surface of the tube, forming scum. Among other things, the concentration of black liquor from sulphate pulp mills with a dry matter level of 65% to 30 or 70% has not been successful in known equipment with a falling film.

The object of the present invention was to eliminate the above drawbacks.

The drop tube 35 long tube evaporator unit 2,71067 having a liquid space, heat exchanger tubes and a separator part according to the present invention is characterized in that the separator part is arranged at the top of the evaporator, the separator part and the liquid space being in the same space with the same pressure 5 connecting pipe or pipes, in which case the pressures in the separator rooms are also practically the same. The method according to the present invention for evaporating liquids using a long-film evaporator operating on the principle of a falling film is characterized in that the steam generated by evaporating the liquid is passed from the liquid space at the bottom

Figure 3 illustrates an evaporator unit according to the present invention, in which the liquid space 6 and the upper separator space 5 are the same space in which the same pressure is applied. A connecting pipe 3 is arranged between the upper separator space 5 and the lower separator space 4, whereby the pressures of the separator spaces 5 and 4 are practically the same.

Advantages of the device and method according to the invention are that only a very small vapor flow resistance generated in the connecting pipe 3 causes a pressure difference. In this case, no equalization of pressure fluctuations takes place through the pipes, which would interfere with the flow of liquid in the pipe 1.

By placing the separator part 5 in the upper part of the evaporator and conducting the generated steam from the space 4 to the space 5 by the connecting pipe 3, the pumping height in the evaporator where the liquid is recirculated from the space 4 to the liquid space 6 is minimized.

In addition, the structure according to the invention has the advantage with respect to the distribution of the liquid in the liquid space 6, e.g. b) the distance of the inner holes of the perforated plate with respect to the liquid 35 coming from the circumference is smaller than if there were no connecting pipe 3.

The structure and method according to the invention provide efficient droplet separation in the separator space 4. (Separation of liquid from 3 71067 vapors).

The liquid portion of the steam / liquid mixture ejecting out of the tubes, heavier, tends to continue to move towards the liquid surface, while the steam makes a 180 ° turn, exiting the connection 5 through the pipe 3 to the separator part 5.

In the separator section 5, the droplets still separate from the steam.

In summary, in a vertical tube evaporator 10 according to the invention operating on a falling film, the pressure between the upper and lower ends of the tubes can be practically equalized by means of a connecting tube or tubes, whereby the falling film remains uniform in each tube along the entire length of the tubes. put-15 on the surface.

Claims (2)

71067 A falling tube long-pipe evaporator unit with a liquid space heat exchanger tubes and a separator part, characterized in that the separator part (5) is arranged on the upper part of the evaporator, the separator part (5) and the liquid space (6) being in the same space, the same pressure is applied that a core pipe or pipes (3) are arranged between the separator parts (4) and (5), whereby the pressures of the separator spaces (4) and (5) are also practically the same. 2. A method for evaporating liquids using a long-film evaporator operating on the principle of a falling film, comprising a liquid space, heat exchanger tubes and a separator space, characterized in that the vapor generated by liquid evaporation is or by means of pipes (3) and that the liquid is circulated from the difference-20 stem (4) to the liquid space (6) by pumping.