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November 2013
Photo 3: A Brazilian sweet sorghum genotype.
120 kg/ha nitrogen, the S120 genotype did the best regarding biomass
yields and syrup production due to its thicker stems. Genotype S868
contained the highest sugar levels (Brix) of 18,75 % at an application rate
of 120 kg/ha (
Photo 2
).
An important quality factor is the sugar content of the syrup, because the
sugars (total soluble solids) are fermented into ethanol. This ethanol can
be used as a blending substance with fossil fuel to produce biofuel. The
main requirement for first generation bio-ethanol production is a Brix of
16% and above.
This value is critical to the correct fermentation processes and the amount
of bio-ethanol to be produced. Results showed Brix levels of 26,79%. The
higher the syrup yield with the correct Brix, the higher the economical
viability and sustainable value of sweet sorghum as an alternative
energy source.
The genotypes which were entered into the nitrogen application rate
trial are not the only sweet sorghum genotypes to be considered for
bio-ethanol production.
Photo 3
for example shows a Brazilian genotype
which was bred for biomass yield and second generation biofuel
production, but was also tested for syrup yield.
The genotypes entered into the ARC’s trial were randomly selected from
22 local genotypes to study the effect of nitrogen levels on the behaviour
of sweet sorghum. Data from other cultivar trials indicated that ten sweet
sorghum genotypes can comply with the requirements (syrup yield and
Brix percentage) for bio-ethanol production.
To conclude
The nitrogen application trial showed promise and can be successfully
incorporated into a bio-ethanol programme. Due to the variance of the
data collected from the two previous seasons, a third season’s data will
be necessary to supply more significant answers. The results can then be
applied to assist producers in South Africa who want to become involved
in the bio-ethanol production industry.
NWU gaan alternatiewe
brandstof verskaf
JOHAN VAN ZYL, KOMMUNIKASIEBEAMPTE, DEPAR-
TEMENT: KOMMUNIKASIE & BEMARKING, NOORD-
WES-UNIVERSITEIT, POTCHEFSTROOMKAMPUS
Daar is na raming drie miljoen huishoudings
in lae-inkomste-gemeenskappe in Suid-Afrika
wat paraffien gebruik vir kosmaak, beligting en
verhitting. Paraffien is egter hoogs vlambaar
en het al in menige informele nedersetting
brande tot gevolg gehad.
Die Noordwes-Universiteit sal binne die vol-
gende twee jaar ‘n bioparaffien-opleidingsen-
trum ter waarde van R2,2 miljoen oprig, met
die uiteindelike doel om lae-inkomste-huishou-
dings van ‘n veiliger alternatief te voorsien.
Hierdie projek sal gedoen word in samewer-
king met die Fakulteit Ingenieurswese en Alen-
sys, ‘n Duitse leier op die gebied van biomassa
en biobrandstofenergie-projekontwikkeling en
-investering. Alensys het wêreldwyd al meer
as 120 biogasaanlegte opgerig en is leiers op
die gebied van kommersiële biobrandstofpro-
duksie.
“As samelewing moet ons die uitdagings van
aardverwarming die hoof bied en terselfder-
tyd die gemeenskappe ophef en ‘n beter
leefruimte vir almal skep. Hierdie projek is ‘n
tree in die rigting van ‘n volhoubare, biogeba-
seerde ekonomie en help om ons mense te leer
hoe om skadelike afval in bruikbare huishoude-
like produkte te omskep,” sê prof Sanette
Marx, projekleier van die bioparaffienaanleg.
Tradisioneel is paraffien ‘n mengsel van kool-
waterstof, soortgelyk aan vliegtuigbrandstof,
wat uit koolstofgebaseerde brandstowwe
geproduseer word en giftige dampe vrystel
wanneer dit verbrand word. In Suid-Afrika is
paraffien verantwoordelik vir 54% van sterftes
in informele nedersettings – weens brande,
respiratoriese siektes en kinders wat per onge-
luk paraffien inkry.
Die opleidingsentrum, toegerus met ‘n oplei-
dingsaanleg, sal afvalkookolie gebruik om
bioparaffien te gebruik wat minder gesond-
heidsgevare inhou. Die doel is volhoubare ken-
nisoordrag deur onderrig van die teoretiese
sowel as die praktiese kant van die kollektering
en verwerking van afvalolie.
Studente sal dus leer hoe om afvalkookolie
te suiwer en op te gradeer tot ‘n uitstekende
alternatiewe kombuisbrandstof (bioparaffien)
en hoe om ‘n verskaffingsketting op te stel vir
die voorsiening van gebruikte olie in Soweto of
soortgelyke geografiese en sosio-ekonomiese
nedersettings.
Ongeveer drie miljoen huishoudings in lae-inkom-
ste-gemeenskappe in Suid-Afrika gebruik paraffien
vir kosmaak.
