Solar energy for hydrogen production : experience and application in South Africa

Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.Hydrogen is expected to be a key role player in the future energy market for stationary, mobile and electrical grid balancing applications if produced from renewable energy sources. Hydrogen energy technologies include direct power from fuel cell, storage for intermittent renewable energy, and power-to-gas (P2G) applications. In the last year P2G has been identified as having a large potential with several possibilities in itself: (1) Hydrogen is produced from excess renewable energy and injected directly into natural gas networks. (2) Hydrogen along with a CO2 emitting source employing the Sabatier process produces synthetic natural gas (SNG). (3) Hydrogen in a bioreactor employing a biocatalyst increases the biogas energy content by reducing CO2 content. At HySA Infrastructure research focus is on hydrogen production from renewable energy as the central technology for the enhancement of the different hydrogen energy prospects. This paper will focus on presenting results from the recently upgraded solar-to-hydrogen system at the HySA Infrastructure center at North-West University. The previous small-scale solar-to-hydrogen system is upgraded to South Africa’s first commercial scale renewable hydrogen production plant. The main purpose of the upgrade is to increase the hydrogen production capacity and improve system performance. System performance includes the increase of overall system efficiency and to reduce the cost of hydrogen. The paper includes prospects of renewable hydrogen in South Africa, and how solar-to-hydrogen research falls into the bigger picture of hydrogen in South Africa.dc201

Microheterogeneous polymeric barriers for membrane contactors : study of gas and vapour separations

Dissertation (Ph. D.) -- University of Stellenbosch, 1996.One copy microfiche.Full text to be digitised and attached to bibliographic record

Development of a controller for fuel cell and supercapacitor application

The growing demand for energy in the world causes a lot of pressure to the environment and the resources used to supply the energy. To ensure a continuous, more reliable and environmentally friendly energy supply system alternative technologies were developed including photovoltaic panels, wind turbines and hydrogen fuel cells. The hydrogen fuel cell in combination with batteries is used in electric vehicles to minimize greenhouse gas emissions and the strain on crude oil. There is however no effective control applied on the different energy sources within the electric vehicle system. This project focused on developing a controller that would determine the energy source supplying the power demanded by the load. The energy sources include a hydrogen fuel cell, batteries and supercapacitors. The load for the system was simulated on an electronic load using a scaled profile of the power needed by an electronic motor that could be installed in a vehicle. The results showed that by using a controller in the system the motor can operate for a longer time than without the controller. Using a controller would thus increase both the lifetime and energy supplying time of the energy sources within the syste

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

New possibilities of electroinduced membrane gas and vapor separation

A novel membrane technique to effect electroinduced facilitated transport of neutral molecules in ion-exchange membranes was suggested. Experiments have been carried out with platinum-coated Nafion membranes in Cu2+/Cu1+ form. This may be a potential technique for the separation of olefin/paraffin mixtures. It was shown that by applying an electric current to the membrane the permeability of ethylene increased 6-fold, compared to the permeability of the initial Pt-coated membrane without current.Articl