US 5,139,620 A · Dimple plate horizontal evaporator effects and method of use

Abstract

Evaporation of saline water in a desalinization process, or evaporation of other types of liquid such as black liquor from paper pulp processing, is accomplished utilizing a multiple effect evaporator. Each effect includes one or more (e.g. first and second) sets of horizontally elongated dimpled plate evaporator elements. Horizontally flowing heating fluid, such as steam, is introduced to the internal passage of at least the second set in all the effects, and a head of circulation liquid is provided to cause liquid being evaporated to flow downwardly from the head over the external surfaces of the sets of dimpled plates in a thin film. The vapor evaporated is drawn through a demistor and is used as the heating fluid for the next effect. Recirculating liquid that has not evaporated and liquid separated by the demisting process are recirculated to the head associated with each effect. Clean condensate--such as distilled water--is withdrawn from the last effect. The liquid to be evaporated may be preheated by passing it through the first sets of dimpled plates countercurrent to the flow of vapor. A vapor compressor may be used to raise the temperature of the vapor withdrawn from the last effect and return it to the heating fluid inlet of the first effect.

Claims30

Dependent claims

A method of evaporating an evaporable liquid using a multiple effect evaporator having at least one set of horizontally elongated dimpled plate evaporator elements disposed in each effect, each set having an internal passage and an external surface, the effects connected in series and including a first, highest temperature, effect and a last, lowest temperature, effect;

comprising the steps of:
(a) introducing horizontally flowing heating fluid into the internal passage of horizontally elongated dimple plate evaporator elements of the first effect, and into the internal passage of horizontally elongated dimple plate evaporator elements in all subsequent effects;
(b) providing a head of circulation liquid to be evaporated at the top of a set of each effect;
(c) causing the liquid to flow downwardly from the head over the external surfaces of the elements of each effect to the bottom of each effect;
(d) withdrawing the vapor of evaporated circulation liquid from each effect while demisting it to separate liquid from the vapor;
(e) recirculating circulation liquid that has not evaporated from the bottom of each effect to the head associated with that effect;
(f) horizontally feeding the withdrawn vapor from each effect to the next effect as the fluid provided in step (a) thereof, except for the last effect;
(g) effecting condensation of vapor fed as the fluid provided in step (a) for the last effect to product clean condensate;
and
(h) withdrawing clean condensate from the last effect.

7 more elements

A multi-stage evaporator having a plurality of effects which are interconnected into a series of effects from a first, highest temperature, to a last, lowest temperature, effect, each effect in the series comprising:

a horizontally elongated vessel, having a top, bottom, first end, and second end;
a first set of elongated in a dimension of elongation dimpled plate evaporator elements, defining an interior passage, and having an exterior surface;
a second set of elongated in a dimension of elongation dimpled plate evaporator elements, defining an interior passage, and having an exterior surface;
means for introducing heating fluid into the interior passage of at least said second set of dimpled plate evaporator elements;
means for mounting said first and second sets of dimpled plate evaporator elements so that they are disposed in said vessel with their dimension of elongation horizontal, with said first set above said second set;
means for introducing circulation liquid to be evaporated adjacent the top of said vessel so that it falls over the exterior surfaces of said first and second sets of elements in a falling film, to cause some of said circulation liquid to be evaporated;
a demistor mounted within said vessel;
means for withdrawing evaporated circulation liquid from said vessel through said demistor;
means for causing circulation liquid not evaporated, and liquid separated by said demistor, to collect at the bottom of said vessel;
and
a circulation liquid outlet from the bottom of said vessel;
and wherein
for each effect except said first effect, said means for introducing heating fluid being connected to said means for withdrawing evaporated circulation liquid from the previous effect.

10 more elements

Dependencies are inferred from the claim text.

Dimple plate horizontal evaporator effects and method of use

Life of this patent

Dimple plate horizontal evaporator effects and method of use

Life of this patent

Abstract

Claims30