Effect of moisture quantity on non-distillation oil extraction from SCG using methanol
- Authors: Mojapelo, Nancy , Mollagee, Mansoor , Muzenda, Edison , Mguni, Liberty L
- Date: 2014
- Subjects: Oil extraction , Methanol , Hexane , Spent coffee grounds
- Type: Article
- Identifier: uj:4902 , ISSN 2349-1442 , http://hdl.handle.net/10210/12997
- Description: Oil was extracted from spent coffee grounds using methanol. Methanol is not a popular solvent for oil extraction because of its toxicity but it is ideal for biodiesel production. The SCG was determined to contain 17.1 % wt% oil by extraction using hexane for 16h. The highest oil extraction 8.5 wt% was observed on a dry sample at a separation temperature of 25 ˚C representing only 50% recovery. Oil extraction was observed to depend on separation temperature and SCG water quantity. The extracted oil was characterised by a number of methods. Fourier-transform infrared spectroscopy (FTIR) results showed no difference in functional groups between hexane and methanol extracted oil. The Refractive Index (RI) results also suggested similarity in fatty acid chain length for oils extracted by these solvent. However, it was observed that oil extracted by hexane had higher amounts of FFA compared to methanol extracted oil.
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Methanol amination using natural clinoptilolite
- Authors: Levin, Lance Robin
- Date: 2012-09-10
- Subjects: Catalysis , Methanol , Clinoptilolite
- Type: Thesis
- Identifier: uj:9846 , http://hdl.handle.net/10210/7249
- Description: M.Tech. , Clinoptilolite possesses acid and base properties, and is hydrothermally stable at high temperatures. It can be reactivated by simple oxidation, and is highly selective due to its unique-shape selectivity. It is also not harmful to the environment and it has shown benefits to soil as well (Mumpton,1977). An initial study of the reactions of methanol amination was done using both natural local and synthetic clinoptilolites. Characterization of each was done before and after modification using XRD, TPD and BET analysis. The BET analysis showed an increase in the surface area and pore diameter of both the natural and synthetic types after acid treatment and calcination. Most interesting of all was the large increase in surface area, where the natural type increased from 16 to 36.7 m 2/g after acid treatment and the synthetic type increased almost 13 times, from 2 to 27.7 m2/g after acid treatment. This effect had a strong influence on the selectivity of methylamines by allowing a larger surface area to be in contact with the feed reagents. The XRD of the treated and untreated natural and synthetic clinoptilolite were compared and discussed. The catalytic properties of zeolites depend on the treatment of clinoptilolite, and the characteristic peaks of natural and the acid treated form can be identified in the XRD plots.The TPD analyses showed that there were two acid sites associated with the clinoptilolite; one weak and one strong. The synthetic clinoptilolite weak acid site also showed a much lower ammonia uptake, than the natural clinoptilolite weak acid site. Clinoptilolite was shown to be successful as a catalyst for the production of dimethylamine with high selectivity. This was attributed to a transition state shape selectivity associated with the clinoptilolite channels. The natural clinoptilolite displayed good selectivities at 400°C and a 5:1 ratio of methanol to ammonia, and gave a high conversion of > 90% ammonia to amines. The synthetic clinoptilolite gave better conversions and lower TMA selectivity than the natural clinoptilolite over a large range of feed ratios and temperatures. This included conversions of over 90% for most ratios (at 400 and 450°C). The natural clinoptilolite gave better results than those obtained using the amorphous clinoptilolite, which is currently used in industry. For example, low TMA selectivity was observed when a ratio of 5:1 or greater (methanol to ammonia) was used. The TMA selectivity is still far lower than the thermodynamic equilibrium selectivities obtained without a catalyst (62%). The catalyst lifetime has been shown to deteriorate with time.
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