A process and apparatus for modification of lignocellulosic materials and products of modified lignocellulosic materials obtained by the process

摘要

A process and apparatus for the preparation of a modified lignocellulosic material by - treating the lignocellulosic material in a first activator zone having an atmosphere of one or more acid anhydrides in vapour form in a gas at a gauge pressure of 0 50 kPag and a temperature of 100 160 °C, and then - treating the lignocellulosic material in a second reactor zone having an atmosphere of a gas at a gauge pressure of 0 50 kPag and a temperature of 120 190 °C, thereafter - stripping the lignocellulosic material with steam or water in a stripper zone, and - optionally further processing. The process is more efficient as compared with the prior art processes by providing a better access of the acid anhydrides to the sites of the reactive lignocellulosic hydroxyl groups (-OH), which are located on the internal surfaces of pores and capillary channels in the lignocellulose. Furthermore, the apparatus is relatively simple. This makes the inventive process and apparatus suitable for a cost-efficient preparation of modified lignocellulosic fibre in industrial scale.