Processes and systems for biomass impregnation to improve conversion to sugars, chemicals, fuels, and materials

A process for impregnating an agricultural residue with a reaction solution, said process comprising:

• (a) providing a biomass feedstock that contains non-condensable gases within biomass pores of said biomass feedstock, wherein said biomass feedstock consists of an agricultural residue;
• (b) introducing a condensable vapor into said biomass pores to remove at least some of said non-condensable gases out of said biomass pores, thereby generating an intermediate biomass material, wherein at least a portion of said condensable vapor remains within said biomass pores;
• (c) exposing said intermediate biomass material to a liquid solution to (i) infiltrate said liquid solution into said biomass pores and (ii) condense at least a portion of said condensable vapor to form a condensed liquid contained within said biomass pores, thereby generating an impregnated biomass material containing a reaction solution comprising said liquid solution and said condensed liquid;
• and
• (d) recovering or further processing said impregnated biomass material,
• wherein step (b) is conducted at a first absolute pressure selected from 0.05 mbar to 5 bar;
• wherein said liquid solution is at a liquid initial temperature prior to said exposing said intermediate biomass material to said liquid solution, and wherein said liquid initial temperature is selected from 20° C. to 210° C.;
• and wherein step (c) is conducted at a second absolute pressure, and wherein said liquid initial temperature is selected such that said liquid initial temperature is about 5° C. to about 20° C. less than the condensation temperature of said condensable vapor calculated at said second absolute pressure.