US 5,932,074 A · Method and an apparatus for the desalination of seawater

Abstract

In a method for the desalination of seawater, there is evaporated and condensed the seawater, within a primary system, and a secondary medium, preferentially untreated water, within a compressor-containing, self-contained secondary system spatially separated from the primary system. The seawater is evaporated by heating in the presence of the secondary medium previously heated in the compressor at excess pressure, the latter medium is evaporated in the secondary system through condensation of the seawater vapour and the seawater vapour is led through a cyclone separator. The total seawater flow supplied to the primary system is subdivided into a first component flow and a second component flow of at least approximately equal magnitude, the first component flow, in a first heat transfer unit through which flows the hot water distillate at the output of the primary system, and the second component flow, in a second heat transfer unit through which flows the discharged hot wash-out, being brought to a temperature approaching the boiling temperature in the primary system. A value between greater than 1 and less than 2 is chosen for the ratio of supplied total seawater quantity per unit of time to wash-out quantity per unit of time (concentration factor CF). A method of this kind is suitable for thermal seawater desalination, enabling the production of germ-free water distillate of high quality under simultaneously lesser concentration of the seawater being evaporated and nonetheless saving energy.

Claims19

Dependent claims

A method for the desalination of seawater, using a primary system having a first and second heat transfer means, and a closed secondary system including a compressor which is separated from the primary system, where the seawater is evaporated and condensed within the primary system and a secondary medium, preferentially untreated water, within the compressor-containing, self-contained secondary system, comprising the steps of:

evaporating the seawater by heating in the presence of the secondary medium previously heated in the compressor at excess pressure and evaporated in the secondary system through condensation of the seawater vapour;
passing the seawater vapour through a cyclone separator and through subsequent condensation of the seawater vapour;
evaporating the secondary medium which has relaxed again in the secondary system;
subdividing the total seawater vapour supplied to the primary system into a first component flow and a second component flow of at least approximately equal magnitude;
bringing the first component flow to a temperature approaching the boiling temperature in the primary system, in the first heat transfer means through which hot water distillate flows at the exit of the primary system;
bringing the second component flow to a temperature approaching the boiling temperature in the primary system, in the second heat transfer means through which the discharged hot wash-out flows;
and
choosing a value between 1.3 and 1.4 for the ratio of supplied total seawater quantity per unit of time to wash-out quantity per unit of time, said ratio being denoted as the concentration factor CF.

5 more elements

An apparatus for the desalination of seawater, including:

a primary system for the seawater;
a self-contained, compressor-containing, closed secondary system for the transfer of heat, separate from the primary system, said primary system being coupled to said secondary system through a first heat exchanger for evaporation of the seawater and a second heat exchanger for condensation of the seawater vapour;
a cyclone separator arranged in the vapour chamber between the evaporator and the condenser;
a distributor for subdividing the total seawater flow supplied to the primary system into a first component flow and a second component flow of approximately equal magnitude;
a first heat transfer unit through which flows the hot water distillate at the output of the primary system in which unit the first component flow is brought to a temperature approaching the boiling temperature in the primary system;
and a second heat transfer unit through which flows the discharged hot wash-out, in which unit the second component flow is brought to a temperature approaching the boiling temperature in the primary system, and two upstream throttle members for controlling a concentration factor (CF) being the ratio of a supplied total seawater quantity per unit of time to wash-out quantity per unit of time with a value between 1.3 and 1.4.

3 more elements

Dependencies are inferred from the claim text.

Method and an apparatus for the desalination of seawater

Life of this patent

Method and an apparatus for the desalination of seawater

Life of this patent

Abstract

Claims19