Method for heat recovery from pre-treated biomass

A method for heat recovery from pre-treated biomass comprising:

• transporting a first liquid having a first temperature into a pre-treatment reactor containing biomass, the first liquid elevating the temperature of the biomass to a second temperature;
• removing the first liquid from the pre-treatment reactor;
• transporting a second liquid having a third temperature into the pre-treatment reactor, the second liquid elevating the temperature of the biomass to a fourth temperature greater than about 75° C., and the fourth temperature is higher than the second temperature;
• allowing the biomass in the pre-treatment reactor to undergo a chemical agent-based pre-treatment reaction process at a temperature of at least the fourth temperature, the chemical agent-based pre-treatment reaction process yielding pre-treated biomass and soluble components;
• transporting a third liquid into the pre-treatment reactor at some point after the chemical agent-based pre-treatment reaction process begins, the pre-treated biomass elevating the temperature of the third liquid to a fifth temperature;
• and
• extracting at least some of the soluble components from the pre-treatment reactor.