Comminution and densification of biomass particles

A process for the conversion of a modified biomass material, said process comprising:

• (a) mixing a solid biomass material with an inorganic material, thereby to produce a solid biomass material mixture;
• (b) exposing the solid biomass material mixture to a toasting temperature in the range of from 105° C. to 140° C. during an exposure time of from 1 minute to 12 hours and under conditions wherein biomass conversion is avoided, thereby to produce a modified biomass material having reduced resistance to mechanical disintegration;
• and
• (c) subjecting the modified biomass material to a conversion reaction,
• wherein prior to or following step (b), the solid biomass material mixture or modified solid biomass material is exposed to a pressure swing explosion by:
• (i) exposing, at a high pressure, said solid biomass material mixture or modified biomass material to a compound selected from the group consisting of steam, ammonia and CO2;
• and
• (ii) allowing the pressure to be reduced to a low pressure;
• wherein the pressure and temperature of said compound in step (i) are such that at least a portion of said compound is liquefied;
• and wherein said low pressure in step (ii) is below said high pressure of step (i) and sufficiently low such that substantially all of said compound is in the form of a gas.