Patent ID: 10513823

Abstract:
Methods and devices are provided for hydrothermal pretreatment of lignocellulosic biomass. A mechanically simple and inexpensive vertical steam reactor is fed with biomass feedstock from the top, while pretreated material is removed from the bottom in steady-state by operation of moveable upper and lower restrictor means, which project across the reactor cross section when engaged. The vertical column of biomass is supported by the upper restrictor means. This is periodically withdrawn from the reactor cross section, permitting the column of biomass to fall by force of gravity onto the lower restrictor means. The upper restrictor means is then re-inserted, after which the lower restrictor means is withdrawn permitting a “plug” of pretreated material to be removed by force of gravity. Using biomass feedstock that has been compressed in a reciprocating piston press to bulk density of at least 500 kg/m3, which can be fed dry into the reactor using simple, inexpensive sluice systems and then wetted inside the reactor, this system provides comparable biomass throughput at a fraction of the cost of traditional commercial hydrothermal pretreatment systems used in “second generation” biorefining.