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Sunds Defibrator Ab

Karl N Cederquist

Stig Daniel Selander

The wet method of combusting organic material dispersed in a liquid comprising waste liquor from wood pulping processes in which the organic material is oxidized by contact with air or other oxygenating gases at a temperature ranging between 180.degree. C. and 340.degree. C. and a correspondingly superatmospheric pressure. The combustion of oxygenation is carried out in two steps: namely, a first step in which the organic material is partially oxidized so that the major portion of the organic substances is converted into carbon dioxide and water, and a minor portion is converted to water-soluble low-molecular fatty acids resistant to oxidation; in a second oxidizing step, the residual oxygen-resistant fatty acids are combusted in the presence of a substantial excess of oxygen-enriched air or other molecular-oxygenating gas so as to liberate the total heat of combustion of the organic material and to impart to the resultant gaseous mixture of effluents a molecular oxygen content sufficient to achieve the partial oxidation in the first step.

Method for wet combustion of organic material

A method of making fiberboard using a substantially closed white water system. One or more layers of separately prepared surface pulp is applied to a layer of base pulp at the wet sheet forming stage. Lignocellulose chips in a pressure-sealed defibrating zone under generation of steam. The steam is separated at the discharge end of the defibrating zone under atmospheric pressure. The atmospheric steam is utilized to presteam the raw chips. The presteamed chips are thereafter dewatered to a moisture content coordinated to the energy demand of the defibrating treatment and the desired generation of steam prior to entering the defibrating zone. The water removed at the dewatering stage is collected for use in preparing the surface layer pulp suspension. A small portion of the base pulp to be used for the surface layer pulp is diverted to a refiner and diluted with water. The major portion of the base pulp is diluted with white water drained off and recycled from the base layer wet sheet forming stage to form a base layer suspension, which suspension is then transported by the white water to the wet sheet forming stage, where the white water and recycled to the base layer suspension stage to form a new base layer suspension. The diverted portion of the base pulp is further diluted with white water recycled from the surface layer forming stage to form a surface layer suspension. A portion of the white water recycled from the wet sheet forming stage to the base layer suspension stage is heated by a portion of the steam separated at the discharge end of the defibrating zone to drive off surplus white water to maintain a constant volume of white water.

Wet method of preparing fiberboard products in a substantially closed

Lignocellulose fiber containing chips, preheated with steam liberated from a previous chip defibration, are dewatered and then defibrated in an atmosphere of saturated steam and in the presence of backwater and suspended in backwater to form a pulp suspension whereafter wet sheets are formed from the pulp suspension, water is mechanically removed from the wet sheets and recycled as backwater to be supplied simultaneously, with dewatered chips, to the defibration step and to form a new pulp suspension and said wet sheets are dried.

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Stockholm, Sweden

Karl N Cederquist