Low-Cost feedstock conversion to biodiesel via ultrasound technology

Biodiesel has attracted increasing interest and has proved to be a good substitute for fossil-based fuels due to its environmental advantages and availability from renewable resources such as refined and waste vegetable oils. Several studies have shown that biodiesel is a better fuel than the fossil-derived diesel in terms of engine performance, emissions reduction, lubricity and environmental benefits. The increasing popularity of biodiesel has generated great demand for its commercial production methods, which in turn calls for the development of technically and economically sound process technologies. This paper explores the applicability of ultrasound in the optimization of low-cost feedstock – in this case waste cooking oil – in the transesterification conversion to biodiesel. It was found that the conversion efficiency of the waste oil using ultrasound was higher than with the mechanical stirring method. The optimized variables of 6:1 methanol/oil ratio at a reaction temperature of 30 °C and a reaction time of 30 min and 0.75% KOH (wt/wt) catalyst concentration was obtained for the transesterification of the waste oil via the use of ultrasound.Web of Scienc

Processing cost analysis of the African biofuels industry with special reference to capital cost estimation techniques

Includes abstract.Includes bibliographical references.Access to energy, in the form of electricity and fuels, is a necessary condition for development. There are several reasons for biofuels to be considered important in many African countries. They include energy security, environmental concerns, foreign exchange savings and socio-economic opportunities for the rural population. Biofuels such as biogas, biodiesel and bioethanol may be easier to commercialise than other alternatives to crude-oil derived fuels, considering performance, infrastructure and other factors. Biofuels are in use in a number of developing countries (including some African ones for example, Mauritius, South Africa, Kenya), and have been commercialised in several OECD countries, as well as Brazil and China. A good understanding of the production cost of biofuels, and the availability of robust and indigenous cost estimation models is essential to their eventual commercialization. However, available process engineering cost estimation relationships and factors are based on plant costs from developed countries, and thus have limited applicability and unknown accuracy when applied to African installations. The need to develop indigenous cost prediction relationships, which is central to economic feasibility studies, is driven not only by the limitations in terms of current data bases and methodologies for the generation of such. There is also a requirement for a more systematic presentation of cost data in equation forms, which will ensure easier and more rapid use of the data in numerical and economic models, and in preliminary design and plant optimisation in a time and cost effective manner, providing decision-makers with key information in the early design stages of a project. It is these shortcomings and challenges that this dissertation attempts to address, through an analysis of the economic input factors, and the development of more robust, indigenous cost estimation relationships for both capital and operating costs for the biofuels process industry in Africa. The conceptual approach developed within this thesis addresses the current data gaps and deficiencies through analyses of establishment and operating costs of existing biofuels plants both on the continent and elsewhere. It aims to determine which factors most influence the production cost, and then proceed to modify known cost estimation tools for both capital and operating costs specifically for African biomass-to-biofuel conversion plants as a function of plant size, feedstock, location, exchange rates, and other site-specific variables. Shortcomings in the use of existing cost estimation models are addressed with the aid of a literature study, supported by the analysis of African biofuels plant establishment (biogas and bio-ethanol) and operating (bio-ethanol) costs‡. Plant establishment costs are analysed at two different levels of detail, corresponding to the concept development and pre-feasibility phases in the project planning cycle

Adsorption study of utilizing calabash Crescentia cujete) seed in the removal of heavy metals from industrial wastewater

This work was carried out to assess the physicochemical parameters and removal of heavy metals from industrial wastewater by activated carbon prepared from calabash seed. Some physicochemical parameters of the wastewater that assessed are pH, temperature, and turbidity, BOD, COD, TS, TDS and TSS. Adsorption studies on the effects of contact time, pH and adsorbent doses on the removal of heavy metals were investigated. The pH and temperature of granite industrial wastewater were 7.5 and 32.5 respectively which are within the permissible limit of WHO (7-8.5 and 32 oC). The wastewater sample shows extremely high turbidity of 2.5 mg/l, biochemical oxygen demand (BOD) of 430 mg/l, chemical oxygen demand (COD) of 283 mg/l, total solid (TS) of 45 mg/l, total dissolved solid (TDS) of 655 mg/l and total suspended solid (TSS) of 965 which are above permissible limit of WHO. The maximum adsorption capacity of Zn (99%) and Fe (88%) were observed at pH 8 and 12 respectively. The pseudo-fist order and pseudo-second order kinetic models were used to fit the kinetic data of the adsorption process, and the result obtained showed that pseudo-second order kinetic model was able to fit the generated adsorption data from the heavy metals considered in this research work due to the regression coefficient R2 of 0.997 value obtained. The study reveals that granite industrial wastewater effluent is one of the industries responsible for polluting the surrounding aquatic environment.Key words: Kinetic study, calabash seed, adsorption, heavy metals, wastewate

Use of coal fly ash as a catalyst in the production of biodiesel

South Africa is largely dependent on the combustion of coal for electricity production; Eskom’s coalfired power stations consume approximately 109 million tons of coal per annum, producing around 25 million tons of ash, to supply the bulk (93%) of South Africa’s electricity. The management of this fly ash has been a concern with various approaches for its beneficial use being investigated. This work presents the results of transesterification reaction using sunflower oil as feedstock with methanol and class F fly ash catalyst derived from a coal fly ash dump in South Africa to produce methyl esters (biodiesel). The fly ash based catalyst was prepared using the wet impregnation procedure with different loadings of potassium. This was characterized by powder X-ray diffraction (XRD), FTIR spectroscopy. The XRD patterns obtained indicated that the structure of the support gradually deformed with an increase in the loading and the extent of decomposition of KNO3 varied with the amount of loading. The influence of various reactions parameters such as loading amount of active components, methanol: oil ratio, reaction time, temperature and catalyst deactivation was investigated. The fly ash based catalyst loaded with 5% wt KNO3 at a reaction temperature of 160ºC exhibited maximum oil conversion (86.13%). The biodiesel synthesized was tested and important fuel properties of the methyl esters (Biodiesel) compared well with ASTM biodiesel standar

Cellulase Production by Aspergillus flavus Linn Isolate NSPR 101 fermented in sawdust, bagasse and corncob

Bagasse, corncob and sawdust were used as lignocellulosic substrates for the production of cellulase enzyme using Aspergillus flavus after ballmilling and pretreatment with caustic soda.  From the fermentation studies, sawdust gave the best result with an enzyme activity value of 0.0743IU/ml while bagasse and corncob gave 0.0573IU/ml and 0.0502IU/ml respectively. The three lignocellulosics gave their maximum enzyme activities at about the twelfth hour of cultivation, suggesting that the 12th hour is the optimum time when the enzyme may be harvested. (African Journal of Biotechnology: 2003 2(6): 150-152

Integration of Seismic and Well Log Data Using Acoustic Impedance for Lithology and Hydrocarbon Evaluation of “Ovi” Field, Niger Delta

This research work is aimed at using acoustic impedance as means of predicting lithology and hydrocarbon away from well control of “Ovi” Field hence providing a detailed evaluation of the hydrocarbon potential of the area. The methodology used involves identification of hydrocarbon bearing reservoirs from well logs using Gamma ray and resistivity logs, wells correlation, petrophysical analysis, well to seismic tie, horizon and fault mapping, generation of structural maps, acoustic impedance crossplot analysis and seismic inversion using model based approach. Three reservoir sand were mapped within the Agbada Formation. From the crossplot of acoustic impedance against gamma ray, porosity and water saturation, the acoustic impedance ranges from 24500-27500 (ft/s)*(g/cc) for shale and 17500-24500 (ft/s)*(g/cc) for sand based on the saturating fluids, the results also shows that acoustic impedance have a linear relationship with water saturation, while porosity have an inverse relationship with acoustic impedance for the study area. Average acoustic impedance maps for reservoir tops generated from the inverted seismic data indicated areas of low acoustic impedance corresponding to hydrocarbon bearing zones that were not detected on the time maps. The result provided detailed information about the subsurface lithology and hydrocarbon saturation away from well control of the study area

A system dynamics approach to technology sustainability assessment : the case of biodiesel developments in South Africa

This paper suggests that a system dynamics approach is best suited to assess the sustainability of technologies, with a specific emphasis on policy interventions for renewable energy in the African context. A bioenergy technology sustainability assessment (BIOTSA) model is subsequently demonstrated by analysing the outcomes of a proposed biodiesel production development on selected sustainability indicators for the Eastern Cape Province of South Africa. In addition, some scenarios are tested to compare how they may improve the selected indicators. The BIOTSA model results are useful to compare dynamic consequences that may result from the proposed biodiesel production development and the respective policies and decisions that may arise from such a development. Nevertheless, recommendations are made to improve the usefulness and practicability of this type of model for technology assessment purposes.http://www.elsevier.com/locate/technovationhb201

Water for small-scale biogas digesters in sub-Saharan Africa

Acknowledgements This work was part-funded by the UK Natural Environment Research Council funded ESPA project, NE/K010441/1 ‘ALTER – Alternative Carbon Investments in Ecosystems for Poverty Alleviation’. We are also grateful to the AUC for funding part of this work under the Afri-Flame project on ‘Adapta- tion of small-scale biogas digesters for use in rural households in sub-Saharan AfricaPeer reviewedPublisher PD

Reducing Carbon Emissions from Forest Conversion for Oil Palm Agriculture in Gabon

Growing demand for palm oil is driving its expansion into the African tropics, potentially leading to significant carbon emissions if tropical forest is converted to palm monoculture. In this first study of a Central African oil palm concession (31,800 ha), we predict that the conversion of 11,500 ha of logged forest to a palm plantation in Gabon will release 1.50 Tg C (95% CI = [1.29, 1.76]). These emissions could be completely offset over 25 years through sequestration in planned forest set-asides given a 2.6:1 ratio of logged to converted forest. Using an agricultural suitability model, we find that careful national land-use planning could largely avoid high carbon emissions while meeting goals for palm oil production. We recommend that Gabon adopts a national carbon threshold for land conversion and requires concession-level set-aside ratios that meet no-net emissions criteria as mechanisms for steering plantations away from high carbon forests