Biomedical Engineering Reference
In-Depth Information
So,
HHV f;ar
HHV f;db
ð
1
M
Þ
5
2
19
:
88
3 ð
1
0
:
35
Þ
5
2
kg
Using Eq. (3.30) again noting that H was given on “dry” basis:
H ar
12
:
92 MJ
=
5
6
:
25
3 ð
1
0
:
35
Þ 5
4
:
06
5
2
0
@
1
A
9
3
06
100
4
:
35
100
LHV f;ar 5
12
;
922
2241
:
7
2
2
11
;
317 kJ
=
kg
5
kg
c. Similarly, values of HHV and LHV on dry ash free basis are found using
Eq. (3.31), which gives:
11
:
31 MJ
=
5
Q
Q
M f
1
1
HHV daf 5
M ash Þ 5
Þ 5
HHV daf
ð
M f 2
M w
ð
1
M
ASH
ð
1
M
ASH
Þ
2
2
2
2
2
1
19
:
88
HHV f;daf 5
HHV db
20
:
52 MJ
=
kg
Þ 5
Þ 5
ð
1
ASH
ð
1
0
:
0313
2
2
1
HHV db
HHV ar
5
ð
1
M
Þ
2
LHV f;db
LHV f;daf
5
1
ASH db
2
kg
where M and ASH are moisture and ash fraction in raw biomass,
respectively.
The biomass contains 3.13% ash on dry basis.
18
:
51
0
:
0313
19
:
09 MJ
=
5
2
5
So ash percentage on ''as-received or wet basis''
ð
ASH
Þ 5
ASH db 3 ð
1
2
M
Þ
3
:
13
3 ð
1
0
:
35
Þ
5
2
03%
Using Eq. (3.31), we can find ASH of the feed on “daf” basis from that
on “as-received” basis as follows;
2
:
5
ASH ar
3
:
13
ASH daf
4
:
83%
5
Þ 5
Þ 5
ð
1
M
ASH
ð
1
035
0
:
00203
2
2
2
2
2. Mass yield
The wood loses 20% of its dry mass during torrefaction. So, the mass yield
on “db” (MY db )
1
dry mass loss
100
(1
0.2)
80%
5
2
5
3
2
5
From Eq. (4.11) :
Mass yield wet basis
ð
MY ar
Þ 5
MY db
3 ð
1
M
Þ
2
80
3 ð
1
0
:
35
Þ
5
5
52%
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