Method for multi-flash evaporation to obtain fresh water from aqueous solution

Claim 1

THE SYSTEM OF FLASH EVAPORATION OF AN ORIGINAL AQUEOUS SOLUTION TO PRODUCE FRESH WATER, SUBSTANTIALLY FREE OF SOLUTE, WHICH COMPRISES THE FOLLOWING STEPS: (A) HEATING THE SAID ORIGINAL SOLUTION TO THE HIGHEST TEMPERATURE IT ENCOUNTERS IN THE SYSTEM, IN A COUNTERCURRENT LIQUID HEAT EXCHANGER WITH A STREAM OF FRESH WATER WHICH IS AT A HIGHER TEMPERATURE DURING THIS STEP AND IS BEING COOLED THEREBY, THE SAID ORIGINAL SOLUTION BEING AT A TEMPERATURE BELOW THE BOILING POINT OF THE SOLUTION AT THE PRESSURE; (B) PASSING THE SAID ORIGINAL SOLUTION DIRECTLY AFTER SAID HEATING INTO PLURAL STAGES AT SUCCESSIVELY LOWER PRESSURES AND TEMPERATURES, REDUCED FROM THAT AT THE DISCHARGE OF SAID LIQUID HEAT EXCHANGER, TO VAPORIZE A PART OF THE WATER IN THE SOLUTION AND TO OBTAIN FRESH WATER VAPOR IN THE RESPECTIVE PLURAL STAGES; (C) DIRECTING THE SAID WATER VAPOR FORMED IN THE RESPECTIVE STAGES TO RESPECTIVE CONDENSING ZONES OF SAID STAGES; (D) PASSING FRESH WATER AT A RELATIVELY LOWER TEMPERATURE THROUGH THE RESPECTIVE CONDENSING ZONES IN COUNTERFLOW RELATIONSHIP TO THE FLOW OF SOLUTION PASSING THROUGH THE STAGES, THE SAID FRESH WATER BEING MAINTAINED AT TEMPERATURES BELOW ITS BOILING POINTS AT THE PRESSURES PREVAILING IN THE RESPECTIVE CONDENSING ZONES; (E) DIRECTLY CONTACTING THE WATER VAPOR WITH THE FRESH WATER TO CONDENSE THE VAPOR AND TO FORM A COMBINED STREAM OF FRESH WATER; (F) REMOVING THE COMBINED STREAM OF FRESH WATER FROM THE LAST CONDENSING ZONE, WHICH IS AT THE HIGHEST TEMPERATURE, AND PASSING THE COMBINED STREAM THROUGH PRIME HEATER WHERE HEAT IS SUPPLIED FROM AN EXTERNAL SOURCE AT THE HIGHER TEMPERATURE IN THE SYSTEM OF FLASH EVAPORATION, THE SAID EXTERNAL HEAT BEING THE ONLY EXTERNAL HEAT SUPPLIED TO THE SYSTEM; (G) PASSING THE HEATED, COMBINED STREAM OF FRESH WATER TO THE SAID COUNTERCURRENT LIQUID HEAT EXCHANGER; AND (H) WITHDRAWING FROM THE SYSTEM A PORTION OF THE COMBINED STREAM OF WATER, WHICH AMOUNT IS APPROXIMATELY EQUAL TO THE TOTAL AMOUNT OF THE VAPORS FORMED IN THE SAID VAPORIZATIONS OF ALL STAGES.

Claim 2

THE SYSTEM OF FLASH EVAPORATION OF AN ORIGINAL AQUEOUS SOLUTION TO PRODUCE FRESH WATER, SUBSTANTIALLY FREE OF SOLUTE, WHICH COMPRISES THE FOLLOWING STEPS: (A) HEATING THE SAID ORIGINAL SOLUTION TO THE HIGHEST TEMPERATURE IT ENCOUNTERS IN THE SYSTEM, IN A COUNTERCURRENT LIQUID HEAT EXCHANGER WITH A STREAM OF FRESH WATER WHICH IS AT A HIGHER TEMPERATURE DURING THIS STEP AND IS BEING COOLED THEREBY, THE SAID ORIGINAL SOLUTION BEING AT A TEMPERATURE BELOW THE BOILING POINT OF THE SOLUTION AT THE PRESSURE; (B) PASSING THE SAID ORIGINAL SOLUTION DIRECTLY AFTER SAID HEATING INTO PLURAL STAGES AT SUCCESSIVELY LOWER PRESSURES AND TEMPERATURES, REDUCED FROM THAT AT THE DISCHARGE OF SAID LIQUID HEAT EXCHANGER, TO VAPORIZE A PART OF THE WATER IN THE SOLUTION AND TO OBTAIN FRESH WATER VAPOR IN THE RESPECTIVE PLURAL STAGES; (C) DIRECTING THE SAID WATER VAPOR FORMED IN THE RESPECTIVE STAGES TO RESPECTIVE CONDENSING ZONES OF SAID STAGES; (D) PASSING FRESH WATER AT A RELATIVELY LOWER TEMPERATURE THROUGH THE RESPECTIVE CONDENSING ZONES IN COUNTERFLOW RELATIONSHIP TO THE FLOW OF SOLUTION PASSING THROUGH THE STAGES, THE SAID FRESH WATER BEING MAINTAINED AT TEMPERATURES BELOW ITS BOILING POINTS AT THE PRESSURES PREVAILING IN THE RESPECTIVE CONDENSING ZONES; (E) DIRECTLY CONTACTING THE WATER VAPOR WITH THE FRESH WATER TO CONDENSE THE VAPOR AND TO FORM A COMBINED STREAM OF FRESH WATER; (F) REMOVING THE COMBINED STREAM OF FRESH WATER FROM THE LAST CONDENSING ZONE, WHICH IS AT THE HIGHEST TEMPERATURE, AND PASSING THE COMBINED STREAM THROUGH PRIME HEATER WHERE HEAT IS SUPPLIED FROM AN EXTERNAL SOURCE AT THE HIGHER TEMPERATURE IN THE SYSTEM OF FLASH EVAPORATION, THE SAID EXTERNAL HEAT BEING THE ONLY EXTERNAL HEAT SUPPLIED TO THE SYSTEM; (G) PASSING THE HEATED, COMBINED STREAM OF FRESH WATER TO THE SAID COUNTERCURRENT LIQUID HEAT EXCHANGER; AND (H) WITHDRAWING FROM THE SYSTEM A PORTION OF THE COMBINED STREAM OF WATER, WHICH AMOUNT IS APPROXIMATELY EQUAL TO THE TOTAL AMOUNT OF THE VAPORS FORMED IN THE SAID VAPORIZATIONS OF ALL STAGES.