The invention relates to the hydrolytic breakdown of plant biomasses via hydrohalic acids, preferably so-called hydrochloric acid. Ligneous biomasses were preferably hydrolyzed in the past because other types of biomasses, for instance straw, are only able to be filled into the reactors with a very low density and they tend towards compacting in the course of the process. The invention solves this problem with two modifications. First of all, pelletizable biomasses are completely or partially loaded in the form of pellets and a heavily increasing filling density is achieved because of that. Secondly, the hydrolysis reactors are tilted, preferably arranged between 30° and 60°, and compacting is prevented. The economic effectiveness of both modifications is to be determined in practical tests for every pelletizable biomass. It is possible that one of the two modifications can be omitted.
