Ademola Rabiu

Parametric analysis of a high temperature pem fuel cell based microcogeneration system

This study focuses on performance analysis of a 1 microcogeneration system based on a high temperature proton exchange membrane (HT-PEM) fuel cell by means of parametric investigation. A mathematical model for a system consisting of a fuel processor (steam reforming reactor and water-gas shift reactor), a HT-PEM fuel cell stack, and the balance-of-plant components was developed. Firstly, the fuel processor performance at different fuel ratios and equivalence ratio was examined. It is shown that high fuel ratios of 0.9–0.95 and equivalence ratios of less than 0.56 are suitable for acceptable carbon monoxide content in the synthetic gas produced. Secondly, a parametric study of the system performance at different fuel and equivalence ratios using key system operating parameters was conducted. Steam-to-carbon ratio, stack operating temperature, and anode stoichiometry were varied to observe the changes in the microcogeneration system. The analysis shows that the system can reach electrical and cogeneration efficiencies of 30% and 84%, respectively.

Process Simulation of Municipal Solid Waste Derived Pellet Gasification for Fuel Production

This investigation proposes a model of syngas creation from Refuse Derived Fuel (RDF) Pellet gasification with air in fixed bed reactor. The model (utilizing Aspen Plus process simulation software) is utilized to model the anticipated results of RDF gasification and to give some processes fundamentals concerning syngas generation from RDF gasification. The fixed bed reactors is an updraft fixed bed reactor which can be divided into 3 sections n (devolatilization, partial oxidation, and steam reforming). The model is based on a combination of modules that the Aspen Plus simulator provides, representing the three stages of gasification. Thermodynamics package used in the simulation comprised the Non- Random Two-Liquid (NRTL) model. The model works on the principle of Gibbs free energy minimization and was validated with experimental data of MSW gasification found in literature. The RYield module was combined with the RGibbs module to describe pyrolysis section, while the RGibbs module was used for the gasification section individually. Proximate and ultimate analysis of RDF pellets and operating conditions used in the model are discussed. The sensitivity analysis module of Aspen Plus was used to research the effect of air equivalence ratio ER and temperature value on the syngas composition, and carbon conversion The results indicate that higher temperature improves gasification as the composition of H2 and CO increase, as well as carbon conversion, until a temperature of 900°C, and higher air equivalence ratio increases the carbon conversion while decreasing syngas quality as there is an increase in CO2 and H. Results obtained are in good agreement of experimentally measured data in literature.

Asphaltene Extraction Capacity of Different Solvents

The ability of paraffinic solvents to reduce the asphaltene content of crude oil was investigated. The solvent n-pentane is added to the crude oil and the asphaltene precipitate was filtered and dried at room temperature. The crude and the precipitate were analysed with GC/MS to further investigate the metallic and non-metallic contents. This experimental procedure was then repeated with n-hexane and n-heptane. Another set of experiments were conducted using a mixture of two solvents at ratios 1:1 and 3:1. For single solvent extraction, the results showed that n-pentane extracted more asphaltenes content of 23.2 g/mL compared to hexane 22.3 g/mL and heptane 22.2 g/mL. Whereas for mixed solvent extraction, the best solvent was that of a hexane-pentane solution of ratio 3:1 with asphaltenes content of 25.2 g/mL followed by that of Pentane-Heptane at ratio 3:1 with asphaltenes content of 25.09 g/mL.

Environmental Emissions Assessment of Coal and Refuse Derived Fuel Incineration Processes by Simulation

Coal has been the predominant source of energy for electricity production in South Africa. Coal combustion process for energy recovery is regarded as heavy pollutant emissions process. Waste derived alternative fuels are widely used for substituting the thermal energy requirement from fossil fuels and reducing the pollutant emission. This paper is a comparison between the burning of coal and RDF as far as fuel qualities and emissions. The ignition of fuel derived from MSW is a promising low-cost retrofitting procedure for coal power plants, having the additional advantage of lessening the volume of waste transfer in landfills. Moreover, co-burning of RDF and coal, as opposed to changing to RDF ignition alone straight from the onset of devoted power plants, permits plant administrators to be adaptable to varieties in the RDF supply.