Timber iQ February - March 2020 // Issue: 48 | Page 43

FEATURES
are their high sulphur content. Sulphur dioxide (SO₂) is emitted
when sulphur-containing fuels are burnt in the presence of
oxygen. See Table 1.
Table 1: Sulphur content of fuels
application is more cost effective. Refer to Table 3. When
accounting for the environmental costs related to SO₂ emissions
and the high volumes of ash to be disposed to certified landfill
sites, or certified end-users, wood chips are a logical choice.
ZOOMING IN ON BROILER HOUSE HEATING
Fuel Sulphur content Heavy Furnace Oil [HFO] 3.25% Low Sulphur HFO [LSO] 1.7% Low Sulphur HFO [LSO] 0.5 - 0.7% A Grade Coal 1.0 - 1.3% CONCLUSIONS
B Grade Coal 0.00 - 0.08% Biomass 0% Methane Rich Gas 0% Biomass chips is a viable alternative to coal, especially in the
poultry industry for decentralised heating of broiler houses, as
well as for central hot water boilers for hatcheries and broiler
houses with central heating systems. It competes with coal
economically and outperforms coal in all environmental aspects.
Physical trials by ABC & CSE on broiler house heating
conclusively proves that the efficiency of the modern wood-fired
systems outperformed the traditional coal-fired heaters by far, as
illustrated in Table 3.
THERMAL ENERGY COST COMPARISON
BETWEEN WOOD CHIPS AND LIGNITE COAL
Table 2 compares the thermal energy cost of biomass chips
supplied by Africa Biomass Company with lignite coal in the
Western Cape and the North West Provinces:
From Table 2, wood chip energy is marginally more expensive
than its coal-fired equivalent in North West, but more than 26%
cheaper in the Western Cape. However, when burner and heat
exchanger efficiencies are considered, the wood-fired
Biomass can give the broiler farmers of the Western Cape a
competitive edge and will contribute millions of cubic meters of
additional runoff into the Breede, Zonderend and Berg river
systems due to the harvesting of invasive alien trees from the
riparian zones of these rivers.
The environmental benefits of using a renewable biofuel are so
overwhelming, that coal will most likely be phased out over the
next couple of years in the poultry industry.
Table 2: Energy cost comparison (Jan 2020)
Fuel Properties
Western Cape
North West Province
Wood chips
by ABC Lignite coal Wood chips
by ABC Lignite coal
Average bulk price (VAT and carbon tax excluded)
delivered to site [R] 940 1 840 940 1 280
Carbon Tax implication [R] Nil 180 Nil 130
Total fuel costs [R] 940 2 020 940 1 410
Average Calorific Value [GJ/t] @ 15% moisture content 15.5 24.5 15.5 24.5
Energy cost [R/GJ] 60.65 82.45 60.65 57.55
Percentage saving Nil 26.44% Nil 5.11%
Average ash content 1.6% 20 – 24% 1.6% 20 – 24%
Table 3: Comparison of decentralised coal heating with an equivalent wood-chip-fired application
Fuel data Coal-fired
Coal-fired
heater
heater
(Western Cape) (North West) Wood-fired
heater
Typical decentralised heating system for a 100 m long x 28 000
chicken broiler house over a typical production cycle in Spring [kg] 10 360
(measured) 10 600
(measured) 13 918
(measured)
Average fuel cost delivered to site; VAT excluded [R/kg] 1.84 1.28 0.94
Carbon Tax effect on price [R/kg] 0.18 0.13 Nil
Total fuel cost [R/kg] 2.02 1.14 0.94
Total fuel cost per house for measured Spring cycle [R] 20 927 14 946 13 083
Fuel cost comparison percentage 160% 114% 100%
Ash generated [kg] 2 280 2 332 209
SO 2 emissions generated [kg] 104 106 5
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// FEBRUARY / MARCH 2020
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