Calculating formulae after Sasse, 1984
1. Vg = Cs • G
2. ha = design-dependent
3. Vg= r • p • h
4. rg = Vg / (π ⋅ h)
5. rd = r + 0.03
6. Vd1 = p • d2 • p • h
7. Vd2 = R3 • p • 2/3
8. R = 3 Vd2 / (π ⋅ 2 / 3)
9. Vd3 = R2 • p • H/3
10. H = R/5
11. Vd3 = R3 • p • 1/15
12. Vd2 : Vd3 = 10 : 1
13. Vd(2+3) = 1.1 Vd2
14. Vd(2+3) = Vd - Vd1
15. hd = hg
16. hdk = hd + structurally dependent free board (0.1 . . . 0.2 m)
<<I>> p127.png Fig. 10.1: Conceptual drawing of a floating-drum biogas plant
Vd = Vdl +Vd2 +Vd3
= digester volume
Vg = gasholder volume
Index g = gas holder
Index d = digester
Sample calculation
1. Vg = 0.6 • 2.5
hg = (specified)
4. r =
5. r = 0.85 (chosen)
6. Vdl = 0.852 •3.14 • 0.7
14. Vd (2+3) = 8.45 - 1.58
8+ 14. R =
Results
= 1.5 m³
= 0.7 m
= 0.82 m
= 1.58 m³
= 6.87 m³
= 1.45 m
Fig. 10.2: Constructional drawing of a
floating-drum plant. Vd = 6.4 m³, Vg =
1.8 m³. Material requirements:
Excavation 16.0 m³, Foundation 1.6
m³, Masonry 1.1 m³, Rendered area
18.0 m², Sheet steel 5.7 m². (Source:
OEKOTOP, Sasse)
113