The utilisation of apricot kernels and shells

Simple item page
dc.contributor.advisorNieuwoudt, I.en_ZA
dc.contributor.authorBotha, Karienen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering.en_ZA
dc.date.accessioned2012-08-27T11:37:21Zen_ZA
dc.date.available2012-08-27T11:37:21Zen_ZA
dc.date.issued1998-01en_ZA
dc.descriptionThesis (MEng)--University of Stellenbosch, 1998.en_ZA
dc.description.abstractENGLISH ABSTRACY: Apricot stones are a waste product that originates in the agricultural industry. In this study the utilisations of this waste pr due by extraction of the kernel oil with supercritical and near-critical fluids and the production of activated carbon from the shell were investigated. The total oil content of three varieties of apricot kernels was determined by soxhlet extractions with hexane and ranged from 25 2 to 42 4%. A pilot plant with a design pressure of 320 bar was designed and constructed to carry out the high-pressure extractions The solvents used for the supercritical and near-critical extractions were carbon dioxide (c -= 31 °C Pc = 73 e bar) and propane (Tc= 97 °c, Pc = 42 5 bar). The carbon dioxide extractions were carried out at the following conditions 100 bar and 28 •c 200 bar and 40 °C. The liquid propane extractions were carried out at 50, 60 and 70 °C, while the supercritical propane extractions were carried out at a temperature of 100 °C and pressures of 55, 93 and 118 bar. At 200 bar and 40 °C the solubility of the oil in the carbon dioxide was only 0 3 weight %. The oil extracted with carbon dioxide retained the natural fragrance of the apricot kernels. The solubility of the oil proved to be higher in the propane with up to 80 % of the 011 extracted at a solvent to kernel ratio of 12 kg/kg. Although the highest extraction rates were achieved with supercritical propane, the high extraction temperature caused roasting of the kernels. Th oil consequently had a burnt odour. The free fatty acid content of the hexane propane and carbon dioxide extracted oil sample were all below O 8 % The major triglyceride groups present in the oil were C .54.78 weight %) and C52 (22 weight%) triglyceride. The carbon dioxide extracted oil contained a slightly higher amount of C52 triglycerides than the hexane and propane extracted oils. The fatty acid distribution of the oil extracted with the various solvents and at various extraction conditions did not vary significantly Linoleic acid (32 3 - 43 4 %) and oleic acid (48 3 - 55 , %) were found to be the major fatty acids present in apricot oil. The apricot kernel oil was found to contain less saturated fatty acids than almost all commercially available seed oils. For the production of activated carbon. the shells were pyrolysed in nitrogen in a tube furnace at 350 °c for 30 min. Activation was carried out in a steam atmosphere various combinations of activation temperatures and times were used and the activated carbons produced were characterised by iodine number. The activated carbon with the highest iodine number 882 mg/g was produced at an activated-on temperature of 850 °C and an activation and time of 2 hours. Gold adsorption experiments were earned out on the activated carbon with the highest iodine number and the results were compared to experiments conducted with a commercial coconut shell activated carbon. The apricot shell activated carbon was found to have a lower gold loading than the coconut shell but displayed a faster gold adsorption rate than the coconut shell carbon This was attributed to a higher percentage of mesopores present in the apricot shell activated carbon. It is concluded that apricot oil and the activated carbon prepared from apricot shells show promising properties which justifies further development.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Appelkoosstene is 'n afvalproduk wat in die landboubedryf ontstaan. In hierdie studie is die benutting van hierdie afval as gevolg van onttrekking van die pitolie met superkritiese en byna-kritiese vloeistowwe en die produksie van geaktiveerde koolstof uit die dop ondersoek. Die totale olie-inhoud van drie variëteite appelkoospitte is deur soxhlet-ekstraksies met heksaan bepaal en het gewissel van 25 2 tot 42 4%. 'n Loodsaanleg met 'n ontwerpdruk van 320 bar is ontwerp en gebou om die hoëdrukekstraksies uit te voer. Die oplosmiddels wat vir die superkritiese en byna-kritiese ekstraksies gebruik is, was koolstofdioksied (c -= 31 °C Pc = 73 e bar) en propaan (Tc= 97 °c, Pc = 42 5 bar). Die koolstofdioksied ekstraksies is uitgevoer by die volgende toestande 100 bar en 28 °C 200 bar en 40 °C. Die vloeibare propaan ekstraksies is uitgevoer by 50, 60 en 70 °C, terwyl die superkritiese propaan ekstraksies by 'n temperatuur van 100 °C en drukke van 55, 93 en 118 bar uitgevoer is. By 200 bar en 40 °C was die oplosbaarheid van die olie in die koolstofdioksied slegs 0 3 gewigs%. Die olie wat met koolstofdioksied onttrek is, het die natuurlike geur van die appelkoospitte behou. Die oplosbaarheid van die olie het geblyk hoër te wees in die propaan met tot 80 % van die 011 wat teen 'n oplosmiddel tot pit verhouding van 12 kg/kg onttrek is. Alhoewel die hoogste ekstraksietempo met superkritiese propaan behaal is, het die hoë ekstraksietemperatuur rooster van die pitte veroorsaak. Die olie het gevolglik 'n verbrande reuk gehad. Die vrye vetsuurinhoud van die heksaanpropaan- en koolstofdioksied-onttrekte oliemonster was almal onder O 8 %. Die belangrikste trigliseriedgroepe teenwoordig in die olie was C .54.78 gewig %) en C52 (22 gewig %) trigliseried. Die koolstofdioksied-onttrekolie het 'n effens hoër hoeveelheid C52-trigliseriede as die heksaan- en propaan-onttrekolies bevat. Die vetsuurverspreiding van die olie wat met die verskillende oplosmiddels onttrek is en by verskillende ekstraksietoestande het nie betekenisvol gevarieer nie Linoleïensuur (32 3 - 43 4 %) en oleïensuur (48 3 - 55 , %) is die belangrikste vetsure teenwoordig in appelkoosolie. Daar is gevind dat die appelkoospitolie minder versadigde vetsure bevat as byna alle kommersieel beskikbare saadolies. Vir die produksie van geaktiveerde koolstof. die doppe is in stikstof in 'n buisoond by 350 °c vir 30 min. Aktivering is in 'n stoomatmosfeer uitgevoer, verskillende kombinasies van aktiveringstemperature en -tye is gebruik en die geaktiveerde koolstowwe wat geproduseer is, is deur jodiumgetal gekenmerk. Die geaktiveerde koolstof met die hoogste jodiumgetal 882 mg/g is geproduseer by 'n geaktiveerde-aan temperatuur van 850 °C en 'n aktivering en tyd van 2 uur. Goudadsorpsie-eksperimente is verdien op die geaktiveerde koolstof met die hoogste jodiumgetal en die resultate is vergelyk met eksperimente wat uitgevoer is met 'n kommersiële klapperdop geaktiveerde koolstof. Daar is gevind dat die appelkoosdop-geaktiveerde koolstof 'n laer goudlading as die klapperskulp het, maar het 'n vinniger goudadsorpsietempo vertoon as die klapperdopkoolstof. Dit is toegeskryf aan 'n hoër persentasie mesopore teenwoordig in die appelkoosdop-geaktiveerde koolstof. Daar word tot die gevolgtrekking gekom dat appelkoosolie en die geaktiveerde koolstof wat uit appelkoosdoppe voorberei is belowende eiendomme wat verdere ontwikkeling regverdig.af_ZA
dc.description.versionMastersen_ZA
dc.format.extent169 pages : illustrationsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/56034en_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshApricot -- Utilizationen_ZA
dc.subject.lcshTriglyceridesen_ZA
dc.subject.lcshCarbon, Activateden_ZA
dc.subject.lcshWaste productsen_ZA
dc.subject.lcshUCTDen_ZA
dc.titleThe utilisation of apricot kernels and shellsen_ZA
dc.typeThesis
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
botha_utilisation_1998.pdf
Size:
68.37 MB
Format:
Adobe Portable Document Format
Description:
Download thesis
Download
Collections
Masters Degrees (Chemical Engineering)