化工原理 第三章-萃取小结

1、Summary: ExtractionNew knowledge Triangle phase equilibrium diagram cross flow process mass balance in triangle diagramOld method theoretical stage model differential contact model minimum solvent/feed ratio engineering considerations Exercise 1 of week 9 Exercise of this weekWhen to use extraction?

2、 Distillation is preferential. When distillation is difficult (azeotropic or relative volatility is close to 1) When distillation is inefficient (eg 1% HAc water) When the component is heat sensitive (eg bioproduct, penicillin)Limitation of extraction AB should be miscible; B and S should be immisci

3、ble or partially miscible; Solvent should be regenerated either through distillation or other methodsApparatus for extraction Performance of commercial extraction equipmenttype Liquid capacity combined streams, ft3/ft2-h HTU /ft plate or stage efficiency (%) spacing between plates or stages, in. typ

4、ical applications mixer-settler 75-100 Duo-Sol lube-oil process spray column 50-250 10-20 ammonia extraction of salt from caustic soda packed column 20-150 5-20 phenol recovery perforated-plate column 10-200 1-20 6-24 30-70 furfural lube-oil process agitated tower 50-100 1-2 80-100 12-24 pharmaceuti

5、cals and organic chemicals Leaching When AB is a solid mixture Solid extraction or leachingEquilibrium is different from liquid extraction How? Without chemical reaction With chemical reactionEquipment is different from liquid extraction How and why? stationary solid beds moving-bed leaching dispersed solid leachingstationary solid beds similar to the cleaning of filtration cakemoving-bed leaching similar to the countercurrent extraction in spray column How is the solid moving?dis