Page 291 - Biosystems Engineering

268 Cha pte r Ei g h t

the malt process) or by acid hydrolysis. Then, conversion of sugar to
alcohol is completed with yeast:

Starch C H O + C H O
I2 22 11 6 12 6
(Maltose) (Dextrose)

Tapioca Material Tapioca is available in plentiful supply in Asia, the
United States, Middle Europe, and Africa. Its production can be
increased through modern cultivation techniques. The process con-
sists in converting the tapioca flour into fermentation sugars with
enzymes prior to fermentation with yeast.
Modern technology uses α-amyl glycosidase, one of the two
enzymes required in the process and then saccharifies the material
into alcohol by yeast.

Cellulose Material
1. From wood: Cellulose wood is hydrolyzed into simple sugars
by means of diluted acid at high temperatures or by concen-
trated acid at low temperatures. Similarly, cellulosic agricul-
tural waste and straws can be used in place of wood.
2. Sulphite waste liquor from paper manufacture: Waste liquor con-
tains 2 to 3.5 percent of sugar, out of which 65 percent is fer-
mentable into alcohol. Before fermentation, all acids in the
liquor are removed by adding calcium. Then, sugar fermenta-
tion is carried out using yeast. Generally, 1 percent of liquor
is converted into alcohol.

Hydrocarbon Gases

1. Hydration of ethylene: Conversion of ethylene to ethyl alcohol
can be carried out in high yield by first treating ethylene with
H SO , forming ethyl sulphuric acid and diethyl sulphate as
2 4
given by following reactions:
C H + H SO = C H HSO
2 4 2 4 2 5 4
C H H. SO = (C H ) SO
2 5 4 2 5 2. 4
When treated with water, ethylsulfuric acid and diethyl sul-
fate become ethanol per the following reactions:

C H . HSO + H O = C H OH + H SO
2 5 4 2 2 5 2 4
(C H ) SO + 2 H O = 2 C H OH + H SO
2 5 2 4 2 2 5 2 4