초록 ▼

The present invention relates to a method for producing pulp cooked under alkaline conditions, in which method cellulose-containing material is brought into contact, in a digester, with an alkaline cooking liquor containing dissolved potassium and sodium compounds, with used spent cooking liquor bei

The present invention relates to a method for producing pulp cooked under alkaline conditions, in which method cellulose-containing material is brought into contact, in a digester, with an alkaline cooking liquor containing dissolved potassium and sodium compounds, with used spent cooking liquor being separated off from the cellulose-containing material and withdrawn for the recovery of energy and chemicals, wherein:

대표청구항 ▼

[ We claim:] [1.] A method for producing pulp cooked under alkaline conditions in a digester and recovery of energy and chemicals produced from the spent cooking liquor generated in the digester, the method comprising the steps of:treating a cellulose-containing material in the digester with an alka

[ We claim:] [1.] A method for producing pulp cooked under alkaline conditions in a digester and recovery of energy and chemicals produced from the spent cooking liquor generated in the digester, the method comprising the steps of:treating a cellulose-containing material in the digester with an alkaline cooking liquor containing dissolved potassium and sodium compounds under conditions to produce pulp and spent cooking liquor;separating out said spent cooking liquor from the pulp by withdrawing said spent cooking liquor from the digester, wherein the spent cooking liquor has a molar ratio between potassium and sodium of greater than 0.25 calculated as (moles potassium) divided by (sum of moles of potassium and moles of sodium);concentrating said withdrawn spent cooking liquor with respect to its content of solid material;subjecting said concentrated spent cooking liquor to partial oxidation in a gasifying reactor, resulting in the formation of a combustible gas which contains entrained solid and/or liquid alkali metal compounds;supplying an effective amount of oxygen-containing gas to the reactor to support the partial oxidation;adjusting an operating temperature in the reactor to between 400.degree. and 900.degree. C., whereby said solid and/or liquid alkali metal compounds have a molar ratio between potassium sulfide and sodium sulfide of greater than 0.4. calculated as (moles of potassium sulfide) divided by (sum moles of potassium sulfide and moles of sodium sulfide);withdrawing said combustible gas containing said alkali metal compounds from the reactor;separating said alkali metal compounds from said combustible gas by bringing said combustible gas into direct contact with a cooling liquid, in which cooling liquid the alkali metal compounds are soluble to form a liquid containing said alkali metal compounds;using said liquid containing alkali metal compounds either wholly or in part for preparing said alkaline cooking liquor; andusing said combustible gas for the production of useful energy.