Patent · US Expired

Two stage process for drying of raw wood material

US6357144B1 · kind B1 · utility

3Cited by

3References

18Claims

0Family size

Assignee

Valmet Fibertech AB · SE

Inventors

Lars-Gunnar Nilsson · Köping, SE
Stefan Backa · Visby, SE
Ulf Persson · Uppsala, SE

Key dates

Filing date	Feb 8, 2000
Grant date	Mar 19, 2002
Priority date	—
Expiry date	Feb 8, 2020

Classification

Technology area (CPC F)Mechanical Engineering; Lighting; Heating
CPC primaryF26B2210/16
WIPO fieldChemical engineering
WIPO sectorChemistry

Abstract

Method for drying wood raw material (10) by means of hot gases (20) supplied to the drying process, in which VOC, apart from water, evaporate from the wood raw material into the gases. The drying process is divided and carried out in at least two sub-steps (I, II), from which process gas (22, 33) is removed separately, and the drying process is thus controlled that VOC evaporate during one of the sub-steps, and the VOC are concentrated to this sub-step. The temperature of the gas containing VOC is increased to a temperature exceeding 180° C. before VOC are oxidized catalytically at said elevated temperature, in order to reduce the discharge of VOC from the drying process.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.