Pulp and Paper Mills Process Facilities 3rd year
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The process used in pulp and paper mills may be?
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Mechanical or Chemical
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Of all the methods employed to reduce wood products into usable fibres, the most widely used process?
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the Kraft process
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The word Kraft orginated from what country and means?
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a German word meaning strength
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Wood is comprised of approximately what?
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50% cellulose, 30% lignin, and 20% hemi-cellulose
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What is lignin?
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lignin is the binder found between the cellulose fibres and must be removed prior to pulp production
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Which type of pulping process uses grinding wheels to shred the wood into sawdust?
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the mechanical pulping process
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Which pulping process is considered to be the least expensive method of preparing wood for paper making?
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the mechanical pulping process
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Mechanical pulping is often used for the manufacture of?
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newsprint
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Cooking is carried out in a vessel called?
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the digester
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Which pulping method accounts for more than 60% of chemical processing?
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the sulphate pulping process
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In the sulphate process, the alkaline fed into the digester is properly referred to as?
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white liquor
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In the sulphate process, the liquor leaving the digester is properly referred to as?
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black liquor
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The liquor that leaves the digester is sent to?
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the recovery boiler
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What purpose do the evaporators present?
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they allow the water to boil from the black liquor
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Lime and heat are added to the green liquor and, after clarification, the green liquor turns into?
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white liquor
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When pulp leaves the pulp washers en route to the paper mill, it is properly referred to as?
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Brown stock
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Waste water from the older bleaching operation contains an environmentally hazardous compound known as?
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dioxins
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Instead of chlorine, newer bleach plants use?
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chlorine dioxide
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What do environmentally-friendly bleaching processes use as their bleaching agents?
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1) oxygen 2) ozone 3)hydrogen peroxide
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Machine drying of the pulp is accomplished by a continuous web or sheet of pulp formed on an endless wire screen called?
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a fourdrinier
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Ideally, the chips fed into the digester are approximately what size?
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1\" by 1\"
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In the recovery boiler, smelt is discharged into a tank of water where it is dissolved to form a solution known as?
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green liquor
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What liquors is burned in the recovery boiler?
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black liquor
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When the pulp leaves the pulp washer en route to the paper mill, it is known as?
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brown stock
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Which type of paper mill uses chemicals such as chlorine, caustic soda, sulphur dioxide, and sulphuric acid?
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older pulp mills
