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Development of a time/temperature logging device to characterise the burning characteristics of biofuelsSmit, Hendrik Christiaan 03 1900 (has links)
Thesis (MScFor (Forest and Wood Science))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: A lab scale combustion unit was designed, in order to characterise the performance of
various woody and wood-based biofuels commonly used for energy production, cooking
and heating. The unit was constructed in a way that it could be repeatedly reused and
provide similar testing conditions, such as airflow for all samples. The requirements
were that it was big enough to contain a fire large enough to yield good
time/temperature profiles and at the same time easy to handle, operate and clean. It
also had to allow the insertion of the thermocouples and flue gas probe.
Time / temperature profiles were obtained and O2, CO2 and CO levels in the flue gas
determined for each biofuel. The samples consisted of the five most commonly used
fuel wood species in the Western Cape, namely Rooikrans, Camelthorn, Bluegum,
Black wattle and vine stumps and five processed products, namely wood pellets, wood
briquettes, commercial charcoal, commercial briquettes and handmade briquettes.
Combustion time/temperature profiles were obtained for all samples and characteristic
values, such as the maximum temperature and coal temperature compared. This
allowed an indication of which product performed better than others in the different
combustion phases and is more suitable for different requirements, such as industrial
heating, or domestic cooking. Even though Bluegum and Camelthorn performed best
overall they were not necessarily suited, for example, for large scale industrial use. It
was found that wood pellets and charcoal were the best biofuel for industrial purposes,
whereas Rooikrans was found to be the best option for small scale use. / AFRIKAANSE OPSOMMING: ‘n Laboratoriumskaal verbrandingseenheid was ontwerp vir die toets en karakterisering
van verskeie houtgebaseerde biomassa soorte algemeen in gebruik vir energie
opwekking, kook en verhitting. Daar was besluit om ‘n eenheid te bou vir herhaalde
gebruik wat die omstandinghede vir elke toets konstant kan hou, bv. ‘n damper om
lugvloei deur die sisteem the beheer. Die eenheid moet groot genoeg wees om veilig ‘n
groot genoeg vuur the bevat waarmee ‘n goeie tyd/temperatuur profiel verkry kan word,
maar terselfdetyd klein genoeg wees om te hanteer, operateer en skoon te maak. Die
eenheid moes ook voorsiening maak vir die insteek van die termostate en gas peilstif.
Tyd/temperatuur profiele is verkry en O2, CO2 en CO vlakke in die uitlaatgas is bepaal
vir elke bio-brandstof. Die monsters was saamgestel uit vyf van die mees algemeen
gebruikte brandhout spesies in die Wes Kaap, naamlik Rooikrans, Kameeldoring,
Bloekom, Swartwattel en wingerdstompies, asook vyf geprosesseerde produkte naamlik
houtpille, houtbrikette, kommersiële steenkool, kommersiële brikette and handgemaakte
brikette.
Verbranding tyd/temperatuur profiele is verkry vir al die monsters en verteenwoord
waardes is daarvan afgelees, bv. die maksimum temperatuur wat bereik is of die
temperatuur waar die vlamme uitgesterf het en slegs koolhitte gemeet word. Hierdie
profiele het dit moontlik gemaak om te identifiseer watter produk het beter gevaar as
ander gedurende die verskillende verbrandingsfases en is beter gepas vir verskillende
gebruike, bv. huishoudelike kook en verhitting. Resultate het gedui dat die Bloekom en
Kameeldoring die beste gevaar het oor all die toetse heen, maar was nie noodwendig
ideaal vir elke spesifieke doel nie. Dit was bevind dat die steenkool en houtpille die
beste gepas is vir industriele gebruik en dat die Rooikrans beter geskik is vir
huishoudelike en kleinskaalse gebruik.
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