Chemical Engineering

Microwave-assisted extraction (MAE) was employed for production of carbohydrates from corn pericarp which is a waste of corn starch production by using hot compressed water as a solvent. Carbohydrates consist of glucose, xylose, arabinose and hemicellulose, while residues were composed of cellulose. By increasing the heating temperature, the solubilization rate increases and reached the value of 75.2% at 220 °C. In order to increase the carbohydrate yield the four independent variables such as heating temperature, come-up time, heating time and solid to liquid ratio were optimized by using the response surface methodology techniques. It includes fractional factorial design, the path of steepest ascent and central composite design. Subsequently, we have applied 2-step of experimental design including fractional factorial design and central composite design for accurate prediction of the optimum condition of MAE of carbohydrates from corn pericarp. In this paper, the total recycle of the corn pericarp have been done by investigating the detailed effects of microwave irradiation on chemical components in corn pericarp. The maximum yield of carbohydrates is about 70.8 % with predominant production of xylo-oligosaccharides.

This study is focus on the conversion and optimization of cassava peel to bioethanol. Classical optimization technique was employed in studying the process variables effect of temperature, acid concentration, cassava peel concentration and time of hydrolysis of cassava peel to glucose. Optimum glucose yield of 78mg/ml was obtained at the temperature of 100oC, acid concentration of 0.40mole, cassava peel concentration of 2g/L and hydrolysis time of 45 minutes. After which the glucose obtained from hydrolysis of cassava peel was fermented to produce bioethanol using a classical optimization technique for the effects of pH, temperature, yeast concentration, glucose concentration and fermentation time on bioethanol yield. Results obtained revealed that the optimum yield of 45.50% of bioethanol was obtained at the pH of 5, fermentation temperature of 35oC, yeast concentration of 10%, glucose concentration of 100g/L and fermentation time of 6 days. The bioethanol produced from cassava peel was characterized to determine the kinematic viscosity, specific gravity, flash point, refractive index, distillation property, sulphur content, octane number and water content. Results obtained on the properties of the bioethanol produced revealed that that the bioethanol produced shows corresponding fuel properties recommended by ASTM, thus providing a good alternative fuel of clean and renewable resource and establishing the potential for bioethanol commercialisation.

This research was aimed at investigating solid particles settling in drilling fluid - Power law fluid in relation to rheological properties of the fluid. Fluid of various densities and rheologies were prepared in the laboratory. Hydroxyl methyl cellulose (HEC) was used in this proportion 5.0, 2.5, 1.5, and 0.5 g/liter to change the rheology of the fluid with a fluid density range from 1.003 to 1.513 g/cm3. The results show that larger particles diameter enhance the particle settling behaviour and increases settling velocities. Also increased fluid density reduces particle settling velocity and increases fluid viscosity. The largest effect on the particle settling is achieved at high fluid viscosity. Therefore, it is recommended that fluids for cutting removal should be designed with a higher consistency index K in order to increase the fluid viscosity and thereby overcome the settling behaviour.