Carbon dioxide purification from fermentation by cryogenic process and distillation process
Abstract
The aim of the study was to reduce on carbon dioxide emission arising from alcoholic
fermentation processes that impact on human health and environment and also assess the
relationship between temperature and pressure parameters during purification of carbon dioxide.
This work was done at BDF distillery. Multi-stage compression, refrigeration, separation and
distillation is cryogenic separation and distillation method that separated majority of the CO2
from the gas mixture with relatively high purity. Subsequently, the separated crude liquid CO2 is
distilled under high pressure and near ambient temperature conditions so that low energy penalty
purification is achieved.
Initially gaseous mixture is stored in the carbon dioxide sack then initially dehydrated before
they are fed into the system, compressed, and cooled down to near ambient temperature thus
achieving the cryogenic separation and liquefaction processes where most of the water is
condensed and can be extracted out afterwards, while the rest is absorbed by a high-efficiency
adsorbent (molecular sieve). At this point, a part of the CO2 is liquefied from the mixed gases.
Using a gas-liquid separator CO2 product is separated from gaseous mixtures of the purge gases.
The crude liquid CO2 separated from the cryogenic separation subsystem is further purified in
the distillation subsystem at temperatures –20 °C to 20 °C and –10°C to 30 °C, to improve its
purity.
A sample of liquefied carbon dioxide after distillation is taken to laboratory for purity test using
carbon dioxide purity tester.
Its purity range was between (99.2- 99.9) % with impurity (2% to 5 %.) content in the separated
liqui