Abstract: A Microwave heating system includes an elongated cylindrical metal cavity intended for heating a voluminous elongated load. The system includes microwave feeding means arranged to generate a single mode of the circular type TEm;n;p (a so-called whispering gallery mode) inside the cavity in order to heat the elongated load, wherein the circumferential index m is at least 4, the radial index n=1 and the axial index p being >0. The heating system is preferably adapted for wood processing.

Abstract: Microwave heating system comprising an elongated cylindrical metal cavity intended for heating a voluminous elongated load.

Abstract: This invention relates to a process for the acetylation of lignocellulosic materials (LM) by (a) bringing the LM into the intimate contact with an acetylating agent comprising acetic anhydride at a temperature from 70.degree.-140.degree. C. and (b) bringing the acetylated LM from step (a) into contact with a superheated chemical agent comprising acetic acid and/or anhydride at a temperature above 140.degree. C. so as to reduce the acetic acid or acetic anhydride content of the acetylated LM to below 10% by weight. LM's treated in this manner have excellent dimensional stability.

Abstract: A method for the manufacture of products containing fibers of lignocellulosic material which involves the disintegration of a lignocellulosic material into fibers and forming and pressing of the fiber web into the product in question, which is preferably in the form of fiberboard (board products). The material that forms the fibers is impregnated with lignin in conjunction with water and at a pH which does not substantially exceed 12.5. When the lignin has been absorbed by the material it is fixed against leaching by water through the modification of said lignin into an essentially water-insoluble form.

Abstract: Chemimechanical pulp is produced from lignocellulosic material in a process in which the material is impregnated in two stages. The material is treated in the first stage with alkaline and, subsequent to passing an intermediate draining and reaction step, in the second stage with a solution that contains peroxide. The quantities of alkali and peroxide charged are fully optional and are independent of one another. The material is then optionally subjected to a further drainage and reaction step, and thereafter pre-heated at a temperature of between 50.degree. C. and 100.degree. C., whereafter the material is refined in one or two stages.The optimal brightness of the processed pulp for a given peroxide consumption is achieved by a balanced division of the peroxide charge between chip impregnation and bleaching.

Abstract: A method for the manufacture of products containing compressed and adhesive-bonded wood chippings, preferably of different sizes. Before the chippings are combined together by glueing to form a product of high dimensional stability, they are impregnated with lignin in conjunction with water and at a pH which essentially does not exceed 12.5. Once the lignin has been absorbed by the wood chippings it is fixed against leaching by the water by the modification of same into an essentially water-insoluble form by impregnating the chips with a weakly acid aqueous solution of a metal salt.

Abstract: Reaction of lignocellulosic material with uncatalyzed acetic anhydride in the absence of any cosolvent is disclosed. The process improves dimensional stability and resistance to biological attack of the lignocellulosic material. Lignocellulosic material is treated by exposure to liquid acetic anhydride for at least a short period of time, after which it is then heated to acetylate the material. The excess anhydride and byproduct acetic acid can be removed by vacuum.

Abstract: In accordance with the invention a chemimechanical pulp is produced from lignocellulosic material, for example wood chips, by subjecting the material to a process in which it is steamed, impregnated with alkali and peroxide, drained, pre-heated, refined and bleached. The material is impregnated in a single stage with a solution containing alkali and peroxide. Subsequent to passing an intermediate drainage and reaction stage, the material is pre-heated to a temperature of from about 50.degree. C., but not above 100.degree. C. The material is then refined in one or two stages. The material can be impregnated by immersing the same in the impregnating solution for a period of up to 20 minutes at a temperature of 15.degree.-60.degree. C., or by compressing the material in a screw press and permitting the compressed material to expand in the impregnating solution.

Abstract: A method for the impregnation of wood to prevent attack by harmful agents such as decay fungi or mould fungi and bacteria by the application of an aqueous solution of an alkali lignin modified into a water-soluble form. Impregnation takes place in two stages, these being an initial stage in which the aqueous solution containing the lignin still in its water-soluble form and with a pH not exceeding 10 is applied to the timber, and a second stage in which the lignin is fixed as a water-insoluble form by the application to the timber of a weakly acidic aqueous solution containing metal ions by the addition of metal salt.