Table of conversion factors and symbols (used in this manual)
The gasifier will be designed for operation in conjunction with the engine from Annex I.
A. Biomass consumption gasifier
The thermal efficiency of the gasifier is taken at 70 per cent
Thermal power consumption (full load): P_{g}/0.7 = 116.6 kW
Heating value of biomass (14% moisture content): 17000 kJ/kg
Biomass consumption gasifier: 116.6/17000 = 0.0069 kg/s = 24.7 kg/in
So the installation under consideration uses 24.7/18.3 = 1.35 kg biomass to produce 1 kWh electricity.
B. Reactor design
For a double throat gasifier (see Chapter IV) holds:
_{}
_{}
S = surface area "throat" = 68 cm² = 1/4 x (^{d}throat)² x d_{throat} = 9.3
The turn down ratio of this type of gasifier can be estimated at a factor 3 (see Chapter 3).
So at loads below 6.1 kVA, tar production of this installation can be expected.
C. Further gasifies dimensions
Once the throat diameter has been fixed, further important gasifier dimensions can be derived from figures 3.3. and 3.4 (Chapter 3).
1. Height h of the nozzle plane above the smallest crosssection of the throat (d_{throat} = d_{t}).h/dt = 1.15
h = 1.15 x 9.3 = 10.7 cm2. Diameter (d_{r}) of the fire box.
d_{r}/d_{t} = 3.0
d_{r} = 3.1 x 9.3 = 29 cm3. Diameter (d_{rl}) of nozzle top ring
d_{rl}/d_{t} = 2.3
d_{rl} = 2.3 x 9.3 = 21.4 cm4. Nozzle diameter (d_{n})
Assumption: gasifier to be equipped with 5 nozzles
Total nozzle area (An): 5 x 1/4 x p x d_{n}²
_{}
d_{n} = 10.4 mm
Energy Units 
J = Joule 
kJ = 1000 J 
GJ = 1000000000 J 
kWh = 3600000J 
TWh = 3.6 x 10^{15} J 
Power Units 
W = Watt 
kW = 1000 W 
MW = 1000000 W 
HP = Horse Power = 745.7 W 
kVA = kilo VoltAmpere 
Force Units 
N = Newton 
kgf = force kilogram 
t = ton = 1000 kgf 
Pressure Units 
Pa = Pascal = N/m² 
kgf/cm² = 98067 Pa 
mm Wg = 9.8067 Pa 
cm Wg = 98.067 Pa 
atm =1.0133 x 10^{5} Pa 
Length Units 
m = meter 
cm = 0.1 m 
mm = 0.001 m 
km = 1000 m 
m m = 0.000.001 m 
Surface Units 
m²= square meter 
cm = 0.01 m 
Mass Units 
kg = kilogram 
mg = 0.000.001 kg 
g = 0.001 kg 
Time Units 
s = second 
min = minute = 60 s 
h = hour = 3600 s 
yr = year 
Volume Units 
m³ = cubic meter 
dm³ = 0.001 m³ 
mm³ = 0.000000001 m³ 
1 = litre = 1 dm³ 
Temperature Units 
K = Kelvin 
°C = degree Celsius 
1° C = 1 K 
Miscellaneous 
Nm³ = normal cubic metre (at 1 atm and 0°C) 
mol = quantity of matter unit 
gram atom = atomic weight expressed in grams 
gram molecule = molecular weight expressed in grams 
ppm = parts per million 
rpm = revolutions per minute 
° = angular degrees 
personkm = one person transported one km 
tonkm = one ton transported one km 
manyr = one man working one year 
Other Units 
Hz = Hertz (frequency) 
V = Volt 
Currencies 
US$ = U.S.A. dollars 

Hfl = Dutch florin 