The biomass pre-treatment pilot consists of a reactor and an expansion tank. The reactor has a volume of 40 litres and withstands a pressure of more than 30 bar, a temperature of 230 °C and a wide pH range. Various types of biomass can be treated in the reactor with high pressure direct steam. The reactor draining creates a steam explosion which opens up the biomass structure and makes the biomass polymers more accessible for subsequent processes.