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Date Submitted: 11/05/2013 04:14 AM
© Whitewater Limited 2012
Engineering Design Considerations
Richard Hill
Whitewater Limited
Consulting Engineers & Scientists
Aims and Objectives
• • •
To be able to calculate resin volumes and vessel sizes To appreciate hydraulic effects To understand regeneration sequence
– counter flow regeneration systems – stratified bed operation – mixed beds
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© Whitewater Limited 2012
To be familiar with vessels and internals To understand EDI
Process Design Parameters
regeneration level (eq/l)
•
Regeneration Ratio = exchange capacity (eq/l) flow rate (m3/h)
•
Hydraulic loading (BV/h) = resin volume (m3) 1
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© Whitewater Limited 2012
EBCT (h) = hydraulic loading
•
Turndown ratio
Maximum flow rate (m3/h) Minimum flow rate (m3/h)
Process Design Parameters
•
The volume of treated water produced per cycle (Q m3) by V litres of resin with capacity Ceq/l treating water with ion exchange load L meq/l is :
Q = (F x T) = (V x C)/L
•
© Whitewater Limited 2012
The resin volume is given by:
V = (F x T x L)/C
where the treatment plant operates for T hours between regenerations at F m3/h
Hydraulic Design
•
For a resin of capacity C eq/l treating a water with ionic concentration L meq/l at a flow of Q m3/h the run time, T h, is:
T
V C Q L
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© Whitewater Limited 2012
where V is the resin volume in litres. Now if the maximum hydraulic loading is W BV/h then:
W
Q 1000 V
and
T
C 1000 Wc
Hydraulic Design
•
So for a typical minimum run of 8h on an anion resin of capacity 0.6 eq/l at 30 BV/h: L 2.5 meq/l
•
© Whitewater Limited 2012
If the anion concentration is greater than 2.5 meq/l the run time will be shorter than the minimum 8 h. If the concentration is less than 2.5 meq/l, the resin volume will be determined by the maximum hydraulic loading and this will set the run time.
•
Hydraulic Design
•
Head loss through resin,
h =...