Chemistry Reference
In-Depth Information
15
70%PS, 30%PKO
60%PS, 40%PKO
10
50%PS, 50%PKO
5
0
5
15
25
35
45
-5
-10
Temperature (°C)
-15
Fig. 15.2
Trend diagram for change in SFC for different blends of palm stearin and palm kernel oil
before and after EIE.
The enzyme is filled into columns arranged in a series configuration and oil is pumped
through the enzyme bed, with four to six columns in one line being the optimum arrangement
(Fig. 15.4). In normal operation, the oil blend enters through the top of reactor no. 1 and
passes down through the enzyme bed before exiting the reactor and transferring to reactor
no. 2. Each reactor has an insulted water jacket to keep the internal temperature at 70
◦
C and
the enzyme itself sits on a sieve plate at the base of the reactor. This acts as a support for the
enzyme particles and as a filter to prevent that the enzymes are washed through the reactors in
this down flow configuration. The non-compressibility of the particles results in low pressure
drop across the reactor (
0.5 bar/reactor) and an average flow of 1.5-2.0 kg oil/kg enzyme/h.
In steady state operation, each reactor contributes to the conversion of the fat, so that it
leaves the reactor chain fully interesterified. Enzyme activity is gradually lost from reactor no.
1 due to the presence in the oils of low levels of oxidation compounds and acids. Eventually,
the enzyme activity is depleted and the spent product is removed from reactor no. 1 and it is
recharged with fresh enzyme. At this point the valves are altered so that the oil now flows
first to reactor no. 2 and then finally exits via reactor no. 1 containing the fresh enzyme
<
Enzymatic - preferential exchange
A
D
E
B
C
F
Fat A
Fat B
Fig. 15.3
Preferential exchange of fatty acids during EIE with Lipozyme TL IM.
