Joint International Conference on Long-term Experiments ...

The main technological and energetical tasks of a thin juice concentration installation
are the following:
• concentration of thin juice up to the limit of avoiding the danger of accidental or
uncontrolled crystallization of saccharose before vacuum apparatus. Generally, in
the conditions of Romania, the thick juice can concentrate up to 69,5-70,00 o Brix
• recovering the evaporated water from the thin juice and ensuring the requierement
of secondary steam necessary for technological purposes specific to the plant
• condensation of the steam received from the vortex wheel under the shape of
condensate, that returns to the Thermoelectric Power Plant of the plant.
The correct operation of the thin juice concentration station is ensured by the operating
way of the main users of secondary steam produced as an effect of juice concentration.
Among the main users, the preheaters of juices and syrups have an important place.
In tables 3, 4 and 5 are present the total coefficients of thermal transfer, in
W/(m 2 .grade), of diffusion juice, clear juice I, thin juice and thick juice or syrups.
Table 3.Total coefficients of thermal transfer, in W/(m 2 .grade) at diffusion juice
preheaters
Temperature of heating Total coefficients of thermal transfer at circulation
agent, speed of juice, in m/s of:
o C
0,1 0,2 0,3 0,4 0,5
Under 100 375 655 836 1017 1220
Over 100 466 815 1045 1275 1513
Table 4. Total coefficients of thermal transfer, in W/(m 2 .grade) at diffusion juice,
clear juice I and thin juice preheaters
Circulation speed
of juice through the
preheaters pipes
Temperature difference, Δt, o C
m/s 10 15 20 40 50
I. For diffusion juice (raw juice)
1,0 710 676 648 627 606 578
1,5 941 901 857 815 780 731
2,0 1163 1164 1101 1045 976 920
12,3 1303 1234 1164 1101 1045 976
2. For clear juice I and thin juice
1,0 2071 1931 1833 1743 1659 1589
1,5 2231 2126 2022 1917 1645 1722
2,0 2440 2280 2182 2043 1952 1645
2,5 2580 2931 2301 2182 2022 1882
404