Methods and systems for direct-contact evaporation and condensation, and desalination methods and systems employing the same

A method for producing fresh water, comprising:

• (a) contacting a first stream of a carrier gas and a first stream of a brine to cause transfer of heat and water from the first stream of the brine to the first stream of the carrier gas to form a second stream of the carrier gas and a second stream of the brine, wherein the first stream of the brine has a brine set point temperature;
• (b) contacting the second stream of the carrier gas and a first stream of a condensate to cause transfer of heat and water from the second stream of the carrier gas to the first stream of the condensate to form a third stream of the carrier gas and a second stream of the condensate, wherein the first stream of the condensate has a condensate set point temperature;
• (c) discharging a portion of the second stream of the brine to form a third stream of the brine;
• (d) combining the third stream of the brine with a stream of makeup brine to form a fourth stream of the brine;
• (e) discharging a portion of the second stream of the carrier gas to form a third stream of the carrier gas;
• (f) combining the third stream of the carrier gas with a makeup carrier gas stream to form the first stream of the carrier gas for recycle to step (a);
• (g) discharging a portion of the second stream of the condensate as a product water stream to thereby form a third stream of the condensate;
• (h) exchanging heat from the third stream of the condensate to the fourth stream of the brine to form a fifth stream of the brine and a fourth stream of the condensate;
• (i) heating the fifth stream of the brine to the brine set point temperature to thereby form the first stream of the brine for recycle to step (a);
• and
• (j) cooling the fourth stream of the condensate to the condensate set point temperature to thereby form the first stream of the condensate for recycle to step (b).

A stacked cassette tower (SCT) useful as a direct-contact condenser and/or a direct-contact evaporator, comprising:

• N interconnected cassettes arranged in a vertical stack, where Nis an integer greater than or equal to two, each cassette having a circular or nearly circular cross-section and comprising:
• a lower chamber, comprising a substantially fluid-impermeable floor;
• an upper chamber;
• a vertical wall, disposed about a circumference of the cassette and defining an outermost extent of the cassette, comprising a plurality of orifices in a portion of the vertical wall associated with the upper chamber;
• a barrier layer, lying between the lower chamber and the upper chamber and comprising a perforation array, the perforation array comprising a plurality of perforations extending through an entirety of a thickness of the barrier layer and permitting flow of a carrier gas from the lower chamber into the upper chamber;
• and
• a downpipe, in fluid communication with the upper chamber and extending downwardly from the upper chamber through an entirety of a height of the lower chamber;
• an outer cylinder, having a circular or nearly circular cross-section and comprising:
• a base;
• at least one carrier gas inlet, in fluid communication with both a source of the carrier gas and the lower chamber of at least one cassette and configured to convey the carrier gas from the source of the carrier gas into the lower chamber of the at least one cassette;
• and
• at least one liquid inlet, in fluid communication with both a source of a liquid and the upper chamber of at least one cassette and configured to convey the liquid from the source of the liquid into the upper chamber of the at least one cassette;
• and
• a lid, comprising a carrier gas outlet,
• wherein an outer diameter of each of the cassettes is less than an inner diameter of the outer cylinder such that an annular space exists within the outer cylinder between the stack of cassettes and the outer cylinder,
• wherein the plurality of orifices in the vertical wall of each cassette is in fluid communication with the annular space and permits flow of the carrier gas from the upper chamber of each cassette into the annular space,
• wherein a lower end of the downpipe of each cassette other than the bottom-most cassette in the stack penetrates through the floor of the lower chamber and thereafter terminates in, and is in fluid communication with, an upper end of the downpipe of the immediately below cassette, and
• wherein a lower end of the downpipe of the bottom-most cassette in the stack is in fluid communication with, and configured to dispense a stream of the liquid into, a reservoir contained within the base of the outer cylinder.