Abstract: The invention proposes an installation (10) in which the impregnation and fractionation of the raw material (MP) are conducted at atmospheric pressure, characterized in that it comprises means (18, 20) for transferring the raw material (MP) successively to a first treatment station (PT1) and a second treatment station (PT2), each comprising means (G1, G2) for temporarily combining, at the first station (PT1), the raw material (MP) with a quantity of a first mixture of organic acids and, at the second station (PT2), for temporarily combining the raw material (MP) with a quantity of a second mixture; and means, after impregnation, for at least partially recovering the quantity of second mixture after impregnation and for recycling at least a portion of the second recovered mixture to form at least partially said first impregnation mixture used at the first station (PT1).

Abstract: The invention proposes an installation (10) in which the impregnation and fractionation of the raw material (MP) are conducted at atmospheric pressure, characterized in that it comprises means (18, 20) for transferring the raw material (MP) successively to a first treatment station (PT1) and a second treatment station (PT2), each comprising means (G1, G2) for temporarily combining, at the first station (PT1), the raw material (MP) with a quantity of a first mixture of organic acids and, at the second station (PT2), for temporarily combining the raw material (MP) with a quantity of a second mixture; and means, after impregnation, for at least partially recovering the quantity of second mixture after impregnation and for recycling at least a portion of the second recovered mixture to form at least partially said first impregnation mixture used at the first station (PT1).

Abstract: A method for producing paper pulp from a lignocellulosie vegetable raw material. The method includes contacting the raw material with a mixture of formic acid and acetic acid (in an amount more than 5 wt. % of the mixture) at a temperature and for a suitable reaction time, the whole being performed at room temperature. The paper pulp is separated from the organic phase and optionally bleached with ozone. The organic phase is treated to enable the recycling of the formic and acetic acids and the extraction of lignins, sugars and excess acetic acid.

Abstract: The invention concerns a method for bleaching different types of paper pulp in two steps at atmospheric pressure and at a temperature not higher than 100 DEG C. The first step consists in contacting the unbleached paste with a mixture of paracetic acid and performic acid. The second step consists in treating the bleached pulp derived from the first step, with a solution of soda and hydrogen peroxide. The resulting pulps exhibit a high index of whiteness and a degree of polymerisation close to unbleached pulps. The method is environmentally safe and non-polluting.

Abstract: Various types of paper pulp are bleached in two steps at atmospheric pressure and at a temperature of less than or equal to 100° C. The first step is carried out by bringing the raw pulp into contact with a mixture of peracetic acid and performic acid. The second step is carried out by treating the bleached pulp obtained from the first step, with a solution of sodium hydroxide and hydrogen peroxide. The pulps obtained have a high brightness value and a degree of polymerization close to the raw pulps. The method is ecological and nonpolluting.

Abstract: A process for the thermal and chemical treatment of lignocellulose-containing biomass and for the production of furfural and cellulose-containing fiber masses. In order to ensure a high yield of furfural:lignocellulose-containing biomass is continuously fed into a cooker containing a cooking liquor and, upon heating of the biomass in a heating zone and guidance of the heated biomass through a consecutive retention zone, cellulose or pretreated biomass is continuously withdrawn from the cooker,cooking liquor is continuously withdrawn from the cooker,the cooking liquor withdrawn is continuously fed to a furfural production plant, andthe cooking liquor at least largely freed from pentoses and furfural is continuously returned to the cooker, wherein heating may be effected by direct steam or via the cooking liquor.

Abstract: In a combined process for the thermal and chemical treatment of lignocellulose-containing biomass and for the production of furfural, biomass is supplied to a cooker in batches, is heated in the cooker under the addition of cooking liquor, and cellulose or pre-treated biomass is withdrawn from the cooker in batches. In order to guarantee a high yield of furfural, cooking liquor is withdrawn from the cooker during the heating phase and is fed to a furfural production plant, and the cooking liquor at least largely freed from pentoses and furfural is returned to the cooker.