Ekono Oy

Per H Ostman

Process for causticizing of an aqueous solution containing alkali

A method for the production of cellulose by the batch cooking process, wherein the digester is filled with chips and cooking liquor, and the batch is cooked at elevated temperature and pressure in order to obtain a delignified cellulose pulp in the digester. For the impregnation stage a cooking liquor is used which contains a substantially higher amount of active chemicals than is required for the cooking of the batch, and before the actual delignification stage the active-chemical batch for the cooking is adjusted and the excess amount of active chemicals is removed by replacing it by part of the hot spent cooking liquor recovered from a previous cooking.

Method for the impregnation and cooking of lignocellulosic material by a

A process for continuous digestion of wood chips which are passed through a heating zone, a digesting zone and a cooling zone in contact with cooking liquor is disclosed. In this process the wood chips are fed into and the liquid phase removed from the input end of the heating zone in such relative quantities that their heat-capacity flows are of approximately the same order of magnitude.

Process for continuous digestion of finely-divided material with heat

The invention relates to a method for evaporation of a solution in a recompression evaporation plant. The solution is evaporated first in known manner by indirect transfer of heat from the recompressed vapor through condensation of said vapor in one or more evaporation units. After pre-evaporation in this fashion the solution is finally evaporated by direct transfer of heat from the overheated vapor which is obtained by recompression of the vapor formed in evaporation. According to the invention this final evaporation is achieved by mixing the solution in finely-divided form with the overheated vapor and then after thermodynamic equilibrium between the vapor and liquid phases has been substantially attained separating the solution from the vapor. The solution thereby obtained can be further evaporated without the addition of heat but with a reduction of pressure by means of conducting it to an expansion vessel which is connected by a vapor line to the suction line of the compressor.

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Jorvas, Finland

Per H Ostman