# Seperation prcoesses fundamentals module

1. May 5, 2009

### christo7

Hi im curently doing my degree in chemical engineering and I'm finding the seperation processes module a bit rough, mainly because of interuption to lectures and the lecturer not being there most of the time.

Anyway I've got an exam coming very soon and need some help, getting desperate! A question below is a sample one which I'm truly stuck with.

1 Batches of 12,000 kg of crushed sugar cane containing 15 wt% sucrose, 20 wt%
fibre and 65 wt% water is to be leached with water in a two-stage cascade
leaching system where equal amounts of fresh water are added to each stage.
Assume that all sucrose is extracted into solution. If 3 kg of solution is entrained
with every kg of fibre:
(a) How much sucrose is extracted into the combined overflows if 8000 kg of
water is used in each stage? [8]
(b) How much water is required in each stage to extract 90 wt% of the sucrose
into the combined overflows [9]
(c) Describe how the leaching system could be improved to extract 95 wt% of
the sucrose. [3]

Can anone help me out?
Thanks
Kristian