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US 5,628,872 AGranted
Method for bleaching pulp with hydrogen peroxide recovered from cellulosic spent liquor
AssigneeKanyr AB
InventorsAke Backlund, Lars Stigsson, Ove Wallergard
Life of this patent
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Abstract
The process for producing hydrogen peroxide, used in the bleaching of pulp, uses the hydrogen generated wholly or partly by the gasification or partial combustion of cellulose spent liquors used in digesting cellulose material to produce the hydrogen peroxide.
Claims22
A method of bleaching pulp comprising the steps of:
- bleaching pulp with hydrogen peroxide;
- partially combusting a spent liquor comprising lignin compounds to form a combustion gas comprising hydrogen gas;
- purifying and concentrating the combustion gas to increase hydrogen gas purity and concentration;
- reacting the hydrogen gas with an alkylanthraquinone in the presence of a catalyst to form hydroquinone which is oxidized with oxygen to thereby form hydrogen peroxide;
- and
- using at least a portion of the formed hydrogen peroxide in the hydrogen peroxide bleaching step.
3 more elements
A method of bleaching pulp comprising the steps of:
- bleaching pulp with hydrogen peroxide;
- partially combusting a spent liquor comprising lignin compounds to form a combustion gas comprising hydrogen gas and carbon monoxide;
- shifting the carbon monoxide to form hydrogen gas by reaction with water;
- purifying and concentrating the combustion gas to increase hydrogen gas purity and concentration;
- reacting the hydrogen gas with an alkylanthraquinone in the presence of a catalyst to form hydroquinone which is oxidized with oxygen to thereby form hydrogen peroxide;
- and
- using at least a portion of the formed hydrogen peroxide in the hydrogen peroxide bleaching step.
4 more elements
Dependencies are inferred from the claim text.