OXYGEN-ALKALINE PULPlNG OF RICE STRAW
Aml Eskander Mikhaiel;
Abstract
Inthe present study alkali pretreatment of rice straw was applied in order to up grade it (by lowering its silica content
before entering the digester) such that the black liquor formed would be of acceptable silica content (maximum l-2o/o Si02 with respect to BL total solids) to be suitable for chemical recovery. Such chemical recovery is not technically feasible at present in case of pulping of rice straw by conventional pulping method since the BL formed contains high silica content (10.7% Si02 with respect to BL TS). Different factors affecting silica reduction during the alkali pretreatment of rice straw were studied such as: % NaOH added (from 1% to 8%), L/G ratio (19:1, 28:1), temperature (70°C and 90°C), time (30-90 min.), and also the effect of washing on silica reduction of NaOH
pretreated rice straw. From the results it can be concluded that:
* NaOH pretreatment of rice straw with 5% NaOH (with
respect to O.D. straw), L/G 19:1, 70°C for 60 min. with continuous stirring in a hydra pulper, followed. by pressing without washing gave about 50% reduction in rice straw silica content (from 12.9% to 6.5%) with actual reduction of
60.8% of Si02input. A further decrease of% Si02 to 3.68%
is possible, but uneconomical- with increase of% NaOH to
8%.
before entering the digester) such that the black liquor formed would be of acceptable silica content (maximum l-2o/o Si02 with respect to BL total solids) to be suitable for chemical recovery. Such chemical recovery is not technically feasible at present in case of pulping of rice straw by conventional pulping method since the BL formed contains high silica content (10.7% Si02 with respect to BL TS). Different factors affecting silica reduction during the alkali pretreatment of rice straw were studied such as: % NaOH added (from 1% to 8%), L/G ratio (19:1, 28:1), temperature (70°C and 90°C), time (30-90 min.), and also the effect of washing on silica reduction of NaOH
pretreated rice straw. From the results it can be concluded that:
* NaOH pretreatment of rice straw with 5% NaOH (with
respect to O.D. straw), L/G 19:1, 70°C for 60 min. with continuous stirring in a hydra pulper, followed. by pressing without washing gave about 50% reduction in rice straw silica content (from 12.9% to 6.5%) with actual reduction of
60.8% of Si02input. A further decrease of% Si02 to 3.68%
is possible, but uneconomical- with increase of% NaOH to
8%.
Other data
| Title | OXYGEN-ALKALINE PULPlNG OF RICE STRAW | Other Titles | هضم قش الأرز بطريقة الأكسجين القلوية | Authors | Aml Eskander Mikhaiel | Issue Date | 1995 |
Recommend this item
Similar Items from Core Recommender Database
Items in Ain Shams Scholar are protected by copyright, with all rights reserved, unless otherwise indicated.