Ethanol production from tropical sugar beet juice

Starch and sugar resources have been extensively researched to find a suitable renewable source of energy to supplement the world’s ever increasing demand for energy while also abating global warming by stemming the addition of earthbound carbon dioxide into the atmosphere. Sugar beet has been used as a source for sugar production for some time, but its development as a large scale agricultural crop in South Africa has been limited by the large production of sugarcane in tropical areas. Recent trials in the Eastern Cape region have shown some promise for cultivating sugar beets on a large scale. In this study, the influence of process variables such as initial sugar concentration (dilution), pH, yeast concentration and nitrogen source addition were investigated to assess the influence of these variables on the bioethanol production potential of tropical sugar beet. High ethanol yields were obtained without dilution (approximately 0.47 g.g sugar-1) while a pH of 4 and a concentration of 5 g.L-1 yeast (Saccharomyces cerevisiae) produced the largest amount of ethanol in the shortest fermentation time. The addition of a nitrogen source such as ammonium sulphate significantly  increased the ethanol yield. It was concluded from the results of this research that bioethanol can be produced economically from tropical sugar beet cultivars grown in South Africa.Key words: Tropical sugar beet, fermentation, dilution, pH, bioethanol yield

Reactor technology options for distributed hydrogen generation via ammonia decomposition: A review

Please help populate SUNScholar with the full text of SU research output. Also - should you need this item urgently, please send us the details and we will try to get hold of the full text as quick possible. E-mail to [email protected]. Thank you.Journal Articles (subsidised)IngenieursweseProsesingenieurswes

Application of membrane technology in a base metal refinery

CITATION: Nel, D. W. et al. 2013. Application of membrane technology in a base metal refinery. Journal of The Southern African Institute of Mining and Metallurgy, 113(4):363-347.The original publication is available at https://www.saimm.co.zaNanofiltration (NF) has attracted much attention over the past few years due to the reduced energy consumption compared to reverse osmosis (RO) and better separation performance compared to ultrafiltration (UF). Although research has been done in the area of NF of nickel ions, sodium ions, and acid separation, not much attention has been given to the separation of high nickel concentrations from sulphuric acid streams. The use of NF for the separation of nickel and acid from a spent nickel electrolyte is an innovative process alternative for future industrial application within a base metal refinery. In this study, the separation performance of a composite polyamide NF membrane on a spent nickel electrolyte was investigated by varying the sodium sulphate concentration in the feed (50–150 g/l ), the trans-membrane pressure (35-55 bar), and cross-flow velocity (1.5-3.5 m/s), and measuring quantities such as total permeate flux, acid rejection, nickel rejection, and sodium rejection. The nickel and acid concentration in the feed were kept constant with variations between 40-60 g/l and 25-40 g/l respectively, while the temperature of the experiments was kept constant at 50˚C. The membrane was found to be very selective for nickel ions, with the rejection of nickel ions varying between 54.4% and 98.2%. The rejection of acid ions varied between -5.9% and 21.8%. The rejection of sodium ions varied between 16.6% and 72.4% at a cross-flow velocity of 2.5 m/s and sodium sulphate concentration of 50 g/l in the feed solution. An increase in trans-membrane pressure increased the rejection of nickel, sodium, and acid ions, while an increase in sodium sulphate concentration decreased the rejection of nickel and acid ions. The total permeate flux was found to increase with an increase in trans-membrane pressure and decrease with an increase in sodium sulphate concentration. The cross-flow velocity had an insignificant effect on the total permeate flux and the rejection of nickel, sodium and acid ions.Publisher's versio