Curriculum reform is a key topic in the engineering education literature, but much of this discussion proceeds with little engagement with the impact of the local context in which the programme resides. This article thus seeks to understand the influence of local contextual dynamics on curriculum reform in engineering education. The empirical study is a comparative analysis of the context for curriculum reform in three different chemical engineering departments on the African continent, located in Kenya, Tanzania and South Africa. All three departments are currently engaged in processes of curriculum reform, but the analysis shows how the different contexts in which these efforts are taking place exert strong shaping effects on the processes and outcomes for that reform.

Alcohol distilleries produce effluents which are strongly acidic, have high Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD), contain strong odour and are dark brown in colour. They cause detrimental environmental effects if they are freely disposed off to the environment. Adopted anaerobic treatment techniques with associated biogas generation have not proved to be very efficient on high strength distillery effluents as substrates. The improvement on mean product yield, effluent stabilization and sterile air tolerance was explored through microbial immobilization on activated natural zeolite and calcium alginate supports. Three experimental set-ups were performed with the first acting as a control and having no support material whereas the second and third having microbial system immobilized unto activated natural zeolite and calcium alginate supports respectively. At the marginal organic loading of 75 kg/m3 (corresponding to undiluted waste water), the unsupported system showed a low yield of 2.1 X 10-3 m3/kg CODt in biogas, whereas the calcium alginate system registered the highest yield of 84.5 X 10-3 m3/kg CODt . Activated natural zeolite system on the other hand showed a yield of 43.6 X 10-3 m3/kg CODt. Based on the effluent stabilization over the same initial marginal organic loading, activated natural zeolite system demonstrated the highest degree in effluent stabilization of 44.0 % as opposed to the unsupported and the calcium alginate system that registered 24.0 % and 41.3 % respectively. Finally, activated natural zeolite supported system showed the longest tolerance to sterile air exposures of 90 minutes. The unsupported system registered a tolerance of 30 minutes whereas the calcium alginate system demonstrated 60 minutes of oxygen tolerance.

Use of microwaves as an alternate heat source to replace conventional heating has been studied in organic synthesis. Microwave irradiation results in faster reaction rates, cleaner production, thereby reducing energy consumption. This also leads to better environmental impacts and is considered green chemistry. This Paper reviews application of microwave irradiation in transesterification reactions for production of biodiesels. Transesterification of Croton Megalocarpus oil using homogeneous sodium hydroxide catalyst was carried out using conventional heating in a water bath, and in a microwave oven. Synthesis of fatty acid methyl ester (FAME) was studied for the reaction variables catalyst concentration, methanol to oil molar feed ratio and reaction time. Results indicated that reaction time was reduced to about 2% for a similar yield when microwave irradiation was employed instead of convective heating. During convectional heating, a FAME yield of 96% corresponded to a methanol-to-oil molar ratio of 6:1, catalyst of 1 %, temperature of 70oC, and reaction time of 60 minute. During microwave irradiation, a yield of 92% was obtained when methanol-to-oil molar ratio was 9:1, catalyst concentration 0.5 %, and reaction time 1 minute. FAME was analyzed through gas chromatography.

Biodiesel is currently mostly produced by homogeneous catalysis. Recently, however, heterogeneous catalysis is being considered as a cheaper alternative to the homogeneous process. Heterogeneous transesterification is considered a green process. The process requires neither catalyst recovery nor aqueous treatment steps and very high yields of ethyl esters can be obtained, close to the theoretical value. However, heterogeneously catalyzed transesterification generally requires more severe operating conditions, and the performance of heterogeneous catalysts is generally lower than that of the commonly used homogeneous catalysts. This study seeks to address this problem by studying the production of biodiesel using eggshells as heterogeneous catalysts. Heterogeneous catalysts can make biodiesel production more energy efficient, and therefore less expensive, by eliminating the need for expensive purification processes that separates the catalyst from reaction products typical in the use of homogeneous catalysts. Matlab was employed for the experimental design, statistical analysis and process modeling. Fatty acid ethyl ester was produced by transesterification of sunflower oil and ethanol using calcined eggshells as a heterogeneous catalyst. To optimize the process, some important variables such as reaction temperature, molar ratio of ethanol to oil and mass weight of catalyst were selected and studied. At the following conditions: 343K of reaction temperature, ethanol to sunflower oil ratio of 9: 1 and 1 mass wt% of catalyst, an optimum fatty acid ethyl ester yield of 92% was obtained, indicating that eggshells have the potential of …

Increased gas emissions from the production and use of petroleum products have negative impact on the environment and more specifically on the flora and fauna. This has necessitated the development of alternative cleaner petroleum substitutes such as biodiesel. In this work, an investigation was carried on a pilot scale batch distillation unit to determine operating parameters that influence the quality of a biodiesel. The parameters studied include reaction temperature, amount of catalyst and alcohol, rate of agitation and reaction time. The biodiesel was produced using the method of transesterification of methanol and sunflower oil with sodium hydroxide as a catalyst. Comparative engine tests on both petrodiesel and biodiesel were performed with a view to ascertain the comparative performance of the two fuels. Over the temperatures considered, the results showed that the transesterification of sunflower oil produced a marked decrease in viscosity and density to a level comparable to those of the petrodiesel. This gave an indication that the biodiesel could be as good as petroleum diesel. Tested on hurricane lumps and pressure stove, it was shown that the biodiesel burned for longer time compared to kerosene and this can be attributed to its low volatility and high calorific value. On blending with kerosene, its capillarity action improved substantially and, on burning, emissions were unnoticed. From the analysis carried out on biodiesel production from sunflower oilseeds, there are indications that the project looks economically viable because the major raw material is readily available at an affordable cost.

Transesterification of oils to produce FAME has traditionally been carried out using homogeneous catalysts. However, the use of homogeneous catalysts without proper downstream processing can have serious environmental implications and attempts are being made to identify a suitable heterogeneous catalyst. Alkaline earth metal oxides have been studied as an alternative, and CaO is found to be the most suitable because of it is readily available and easy to handle. Study was made to see the effectiveness of CaO as a catalyst for FAME. It was found that CaO and NanoCaO contain a significant amount of hydroxide and carbonate leading to very poor activity. CaO was calcined to eliminate the hydroxide and carbonate. Calcination of CaO was carried out at 500, 700, 800 and 900oC, and the resulting samples analyzed through XRD. Results indicated that amounts of hydroxide and carbonate decreased as the calcination temperature was increased, and at calcination temperatures above 800oC sample consisted mostly of calcium oxide. Re-oxidized catalyst was obtained by hydrating CaO with water and thereafter calcining the calcium hydroxide to reconvert into oxide form. CaO, NanoCaO and Re-oxidized CaO were characterized through BET surface area, XRD, TEM, and basicity by Hammett indicator method. Transesterification of Croton Megalocarpus oil was carried out with methanol using a 9:1 methanol to oil molar ratio at 60oC for 3 hours using 2% catalyst. Product was analyzed for FAME by GC. Uncalcined catalyst gave a very low yield of 3 %. Yields for calcined catalysts ranged from 28 to 35%. Results indicate that pretreatment of CaO through calcination and re-oxidation increase the catalytic activity. It also shows that basicity of catalyst is a better indicator of activity as compared to BET surface area. Re-oxidized CaO catalyst with a lower BET surface area had a higher basicity, and a higher activity. 

Tea, produced from the evergreen plant, Camellia Sinensis, is the most widely consumed beverage in the world after water. Although tea processing has now diversified into various speciality end products such as instant, white, oolong, iced, flavoured, and various blends, the most abundantly produced tea product in the world is fermented black tea. Black tea production is essentially a “dry” process, as no water is used at any of the production process steps. However liquid waste is generated due to the use of water for cleaning process equipment and factory premises. The waste exits the factory as coloured liquid effluent that must be treated before being discharged into rivers, lakes and other fresh water bodies. This paper presents findings of a study carried out to evaluate the performance of a combined adsorption and advanced oxidation process in removing colour from tea industry wastewater. The variables explored were the effects of sorbent mass, oxidant dosage, solution pH, agitation rate and temperature, on the decolouration of tea industry effluent. The results indicate that the combined adsorption and advanced oxidation is most effective at pH 3 wherein the effluent colour was reduced from 478 Pt-Co colour units to 8 Pt-Co colour units. The latter meets the NEMA recommended limit for discharge of colored effluents.

Biodiesels are biofuels made from renewable sources such as vegetable oils originating from plants and animal fats. Transesterification reaction is carried out by reacting triglycerides in oil/fat with an alcohol in presence of a catalyst. Important process variables are reaction temperature, time, reactant concentration and the catalyst. Catalysts can be homogeneous or heterogeneous. Homogeneous catalysts are liquid phase ionic acid and base, enzymes, and non-ionic organic base compounds. Heterogeneous catalysts are acid and base type. Examples of acid heterogeneous catalysts are ion-exchange resins, tungstated and sulphated zirconia, metal complexes and zeolite. Base heterogeneous catalysts consist of metal oxides in pure form or over support, zeolites, clays and nonoxides. Paper gives a brief introduction of catalytic transesterification process and a detailed review of solid basic catalysts. It is found that these catalysts are selective to feed and preparation method. Acid solid catalysts are suitable for high free fatty acid feed. Basic solid catalyst give a better yield compared to acid solid catalysts but lead to soap formation if feed has high free fatty acid.

Most industrial processes like fermentation, hydrogenation, oxidation, water treatment, petrochemical, nuclear and aerospace involve intimate contact between continuous phase and dispersed phase. Bubble columns and external loop airlifts are commonly used in these operations. Although these reactors are widely used, and extensive research has been carried out there exists no perfect model to characterize the local hydrodynamics and mass transfer. Computational fluid dynamics has also evolved recently trying to model the flow and transfer within these reactors but a lot of results are conflicting. Besides, there is a need to validate these results with experimental work. This work is dedicated to the experimental methods of measuring the local parameters such as the gas hold-up, the bubble velocities, the liquid velocity, bubble sizes. Two intrusive methods are used in this study, hot film anemometry for measurements of liquid phase and bi-optic probe for the gas phase. Although intrusive methods may interfere with fluid flow, presently they are the most adapted for real industrial processes with opaque equipment walls and high gas hold-ups compared to non-intrusive methods such as imagery. In this study, an external loop airlift of 16.5 l capacity is used. Local variables are measured in the riser of an external loop airlift reactor in air/water medium. The results are presented in the form of the radial profiles of void fraction, bubble diameter, liquid velocities at superficial gas velocities ranging from 0.03 to 0.11 m/s. The axial variations of the same parameters are also investigated. The results suggest that the bi-optical probe and hot film anemometer can reliably predict flow characteristics in high gas hold up contactors.