The one
of the main factor that provides high quality of ethanol food grade is
distillation columns. Nowadays before the producers are strict market
conditions on qualitative of ethanol, and reduced specific energy costs per
unit of output. Nowadays manufacturers have strict conditions on the
quantitative and organoleptic indicators of alcohol quality. At once market
conditions dictate reduced specific energy costs per unit of output. This
problem can be solved only by constantly improving technology of removing impurities
by increasing the efficiency of mass transfer. Application of cyclic modes is
one of the methods to increase the efficiency of interaction phases in
distillation column, which essentially boils down to a circular motion phases
in the contact zone. Mass transfer occurs on a tray in the absence of fluid
flow. This allows you to achieve hydrodynamic regime that close to the ideal
displacement as in a liquid, and a pair in real conditions. There is observed
especially significant difference between standard and cyclic processes at high
reflux. This scheme of contact phase makes it possible to get number of structural and technological
advantages : reduce the number of trays in the column 2 ... 2.5 times; reduce
square of trays in 1.5 ... 2 times; reduce steam consumption is 1.5 .... 2, 5
times; increase the load on the liquid 1.5 ... 2 times; improve quality and
increase the additional output of ethanol.
Let
demonstrate the benefits of the transfer distillation column in cyclic mode on
the example of the column final purification and column of concentration of
impurities.
The Column
of the final purification of ethanol, operating in the hydroselection mode:
reduces the content of methanol in 1.3 ... 2 times, reduces the aldehydes
content of 0.2 mg / liter; increases oxidation ethanol per 1 ... 2 min;
improves organoleptic properties of ethanol. This specific steam consumption in
the cyclic mode is 0.3 ... 0.4 kg / liter (for bubble column in standard mode
is 0.6 ... 0.8 kg / liter).
The Column
of impurities concentration performs the function of additional hydroselection
column for the purification of contaminated flows. Release of additional
ethanol for 3 ... 4 % is possible due to the higher concentration of impurities
main character (esters and aldehydes) namely of 0.6 ... 0.7 % of plant capacity
and specific consumption of steam 0.07 ... 0.08 kg / liter (for bubble column
in standard mode is 0.3 ... 0.4 kg / liter).
Distillation
column in a cyclic mode allow to reduce capital costs for the construction of
new and reconstruction of existing ethanol plant, while reducing the cost and
improving the quality of the final product.
