Patent ID: 7566383

Claim:
A method for transferring heat from a first hot biomass to a cold biomass, comprising the steps of: (a) providing a heat recovery system, comprising: a flash cooler; and a direct contact condenser; (b) providing a first hot biomass stream characterized by a first temperature and a first pressure, and having a liquid with a first saturation water vapor pressure at the first temperature; (c) introducing the first hot biomass stream into the flash cooler, the flash cooler having a second pressure, where the second pressure is less than the first saturation water vapor pressure and the second pressure is less than the first pressure; (d) flashing a liquid portion of the first hot biomass to form a first hot biomass vapor and an unflashed first hot biomass component, the first hot biomass vapor having a second temperature that is less than the first temperature; (e) removing the first hot biomass vapor from the flash cooler; (f) transferring the first hot biomass vapor into the direct contact condenser; (g) introducing a cold biomass into the direct contact condenser, the cold biomass having a third temperature, where the third temperature is less than the second temperature of the first hot biomass vapor; and (h) contacting the first hot biomass vapor with the cold biomass for a time sufficient to transfer heat from the first hot biomass vapor to the cold biomass, wherein the first hot biomass vapor condenses onto the cold biomass, wherein the transfer of heat to the cold biomass increases the temperature of the cold biomass to form a heated cold biomass having a fourth temperature, where the fourth temperature is greater than the third temperature.