Biomedical Engineering Reference
In-Depth Information
Similarly, the oxygen from the air flow to the gasifier is:
0
:
232
2
:
76
0
:
640 kg
=
kg feed
3
5
The steam supplied per kilogram of fuel is 0.117 kg, so the oxygen associated
with the steam supply is:
0
:
117
3
ð
8
=
9
Þ
5
0
:
104 kg
=
kg feed
Oxygen also enters through the 7.3% moisture in the fuel and the 1% mois-
ture in the air feed. The total oxygen from moisture is:
0
:
073
3
ð
8
=
9
Þ
1
0
:
01
2
:
76
3
ð
8
=
9
Þ
5
0
:
065
0
:
0245
3
1
5
0
:
0895 kg
=
kg feed
The total oxygen flow to the gasifier, including the 7% that comes with the
fuel, is:
0
:
640
0
:
104
0
:
0895
0
:
07
0
:
9035 kg O
2
=
kg feed
1
1
1
5
Hydrogen Balance
The total hydrogen inflow to the gasifier with fuel, steam, and moisture in the
fuel and moisture in the air is:
0
:
055
0
:
117
=
9
0
:
073
=
9
0
:
0276
=
9
0
:
0792 kg
=
kg feed
1
1
1
5
The hydrogen leaving with H
2
and CH
4
in dry gas, noting that 1 mol of CH
4
contributes 2 mol of H
2
, is:
ð
0
:
15
2
0
:
025
Þ
3
0
:
145
0
:
029 kmol
=
kg feed
0
:
029
2
1
3
5
5
3
kg feed
To find the moisture in the product gas, we deduct the hydrogen in the dry
gas from the total hydrogen inflow obtained earlier, using the hydrogen balance:
5
0
:
058 kg hydrogen
=
Hydrogen inflow
hydrogen out through dry product gas
0
:
0792
0
:
058
2
5
2
0
:
0212 kg
=
kg feed
5
The steam or moisture associated with this hydrogen in the gas is:
0
:
0212
3
ð
18
=
2
Þ
5
0
:
1908 kg
=
kg feed
Carbon Balance
The carbon-bearing gases—CO, CO
2
, and CH
4
in the dry gas each contains
1 mol of carbon. So the total carbon in 0.145 kmol/kg of fuel product gas is:
ð
0
:
275
0
:
035
0
:
025
Þ
3
0
:
145
0
:
0485 kg mol
=
kg feed
0
:
0485
12
1
1
5
5
3
kg feed
The carbon input, as found from the composition of the feed, is 0.665 kg/kg
feed. The carbon conversion efficiency is found by dividing the carbon in the
product gas by that in the fuel is equal to:
0
:
583 kg
=
5
ð
0
:
583
=
0
:
665
Þ
3
100
5
87
:
6%
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