US 8,691,050 B2 · Methods and devices for continuous transfer of particulate and/or fibrous material between two zones with different temperatures and pressures

Abstract

Continuous transfer of particulate material into pressurized steam reactors is provided by “flow feeder” methods and devices. Material such as lignocellulosic biomass feedstocks are compacted into a “low density” plug, <700 kg/m3, which provides a dynamic seal against pressurized steam through exploitation of a steam condensation zone. The rate at which the steam condensation zone moves into the “low density” plug is offset by the rate at which compacted material is fed into the pressurized reactor. Preferred devices compact material within a flow feeder chamber by use of a loading device that works against counter-pressure provided by an unloading device. Compacted material is actively disintegrated and fed into the reactor by the unloading device. In preferred embodiments, compacted material is fed in a steady-state operation in which the interface between the steam condensation zone and the low pressure inlet zone remains stationary within the flow feeder chamber.

Claims30

Dependent claims

A method for transferring particulate and/or fibrous feedstock from a zone 1 with lower temperature T1 and a lower pressure P1 into a zone 2 having a higher temperature T2 and a higher pressure P2, wherein P2 mainly derives from vapour which will condense at T1, comprising

compaction of said feedstock in a flow feeder chamber to form a moving plug having a density at which vapour from P2 can penetrate said moving plug, forming a condensation front that moves at a controllable velocity towards P1 into said plug, counter-current to the motion of said plug which is from P1 towards P2, and
avoiding leakage of vapour from P2 to P1 by adjusting the velocity at which said condensation front moves towards P1 into said plug relative to the velocity at which said plug moves from P1 to P2.

An apparatus for transferring particulate and/or fibrous feedstock from a zone 1 with a lower temperature T1 and a lower pressure P1 into a zone 2 having a higher temperature T2 and a higher pressure P2, wherein P2 derives primarily from vapour which will condense at T1, adapted to conduct the transfer by forming a continuous flow of compacted feedstock moving from zone 1 to zone 2, said apparatus comprising

a cylindrical flow feeder chamber defined by a wall and having an inlet opening for loading said feedstock from zone 1, and an outlet at an open unloading end connected to zone 2
a loading device being a screw or a piston screw, that is situated so as to be loaded with said feedstock through the inlet opening, for loading said feedstock into the flow feeder chamber, said screw having a length and receiving the feedstock close to a shaft end thereof and delivering it at an opposite free end thereof, the distance between a last screw blade of the loading device and the outlet of the flow feeder chamber being longer than the length of the screw of said loading device,
an axially movable unloading device situated at the unloading end of the flow feeder chamber,
several sensors placed along the wall of the flow feeder chamber for monitoring pressure and/or temperature and
a discharge chamber, which can be sealed in a pressure tight connection between the flow feeder chamber and zone 2.

2 more elements

Dependencies are inferred from the claim text.

Methods and devices for continuous transfer of particulate and/or fibrous material between two zones with different temperatures and pressures

Life of this patent

Methods and devices for continuous transfer of particulate and/or fibrous material between two zones with different temperatures and pressures

Life of this patent

Abstract

Claims30