Experimental and Kinetic Modelling Studies on the Acid-Hydrolysis of Banyan Wood Cellulose to Glucose

Bioconversion of agricultural waste products to produce value-added fuels and chemicals offers potential economical, environmental and strategic advantages over traditional fossil-based products. The kinetics of acid hydrolysis of cellulose isolated from banyan wood sawdust was studied at sulphuric acid concentration of 2 to 5 M (moles/dm3) and temperature ranging between 40 – 80 oC in a stirred conical flask which served as a batch reactor. The results showed that the rate of acid hydrolysis by virtue of glucose yield generally increased with increase in acid concentration and temperature used. The experimental data were fitted to integrated first order rate kinetics and the results obtained suggested a first order rate of glucose formation from banyan wood cellulose. The specific rate constant relatively increased with increase in acid concentration and temperature, respectively. The activation energy estimated from Arrhenius equation was found to be 6.75 kJ/mole. This value suggests the ease with which hydrolysis can occur between the four agricultural wastes cellulose. Keywords: Acid-hydrolysis; Arrhenius equation; First-order kinetics; Glucose; Wood cellulose

Modelling the Kinetics of Biogas Generation from Mesophilic Anaerobic Co-Digestion of Sewage Sludge with Municipal Organic Waste

This work investigated the effect of municipal organic waste as co-substrate in the anaerobic digestion of industrial sewage sludge for efficient and high biogas production. The biogas experiments were carried out in two different 30 L anaerobic digesters D1 and D2 which contained sewage sludge and mixture of sewage and municipal organic waste, respectively and were incubated for 25 days at ambient mesophilic temperatures (28 oC to 32 °C). The results showed that co-digestion of sewage sludge with municipal organic waste as co-substrate reduced start-up time for biogas generation and increased biogas yield by 132% as compared to sewage sludge alone. Peak biogas production was obtained for both digesters at pH of 6.85 and 7.85 as well as temperature of 30 and 31.5oC, respectively. Modelling study revealed that exponential plot simulated better than the linear plot, the biogas production rates in digester D1 (sewage sludge) and D2 (mixture of sewage sludge and municipal organic waste), respectively. Logistic growth model and modified Gompertz plot showed better correlation of cumulative biogas production than exponential rise to maximum plot. These results show that biogas production can be enhanced efficiently through co-digestion process. Keywords: Anaerobic digestion; Biogas; Municipal waste; Sewage sludge; Kinetic model

Removal of Phenol from Paint Wastewater by Adsorption onto Phosphoric Acid Activated Carbon Produced from Coconut Shell: Isothermal and Kinetic Modelling Studies

The feasibility of using phosphoric acid activated carbon produced from coconut shell to remove phenol from paint wastewater under batch mode was investigated. The results showed that adsorption of phenol was contact time, adsorbent particle size and adsorbent dosage dependent. The batch equilibrium adsorption data were analyzed by two-parameter adsorption isotherm models of Langmuir and Freundlich using the linear regression method. Both isotherm models fitted very well to the equilibrium adsorption data, however, the Freundlich isotherm equation provided the best model to describe the adsorption of phenol onto coconut shell activated carbon. Adsorption capacity of 2.01 mg/g and adsorption intensity of 1.07 was obtained for granular coconut shell activated carbon and corresponding 3.63 mg/g and 1.55 for powdered coconut shell activated carbon at 30 oC. The adsorption kinetic data were fitted to three adsorption kinetic models (pseudo first-order, pseudo second-order and intra-particle diffusion) using the linear regression method. The three kinetic models fitted well to the adsorption kinetic data; however, the pseudo second-order kinetic model gave the best fit and the adsorption mechanism was controlled by film diffusion. Thus, phosphoric acid activated carbon produced from coconut shell has the potential for application as an effective adsorbent for phenol removal from wastewater. Keywords: Activated carbon; Adsorption isotherms; Adsorption kinetics; coconut shell; paint wastewaters

Modelling the Kinetics of Biogas Production From Mesophilic Anaerobic Co-Digestion of Cow Dung with Plantain Peels

This work investigated the effect of plantain peels as co-substrate in the anaerobic digestion of cow dung for efficient and high biogas production. The biogas experiments were carried out in two different 5 L anaerobic digesters and incubated for 40 days at ambient mesophilic temperatures (28 oC to 34 °C). The results showed that co-digestion of cow dung with plantain peels as co-substrate reduced start-up time for biogas generation and increased biogas yield by 18% as compared to cow dung alone. Peak biogas production was obtained for both digesters at pH of 6.7 and 6.9 as well as temperature of 29 and 30oC, respectively. Modelling study revealed that exponential plot simulated better in both ascending and descending limb than the linear plot the biogas production rates in biogas production from cow dung co-digested with plantain peels and cow dung alone, respectively. Logistic growth model and modified Gompertz plot showed better correlation of cumulative biogas production than exponential rise to maximum plot. These results show that biogas production can be enhanced efficiently through co-digestion process

AN EVALUATION OF TECHNICAL AND ECONOMIC PERFORMANCE INDICATORS IN A POLYURETHANE FOAM MANUFACTURING INDUSTRY IN NIGERIA

The work is aimed at investigating, analyzing and comparing the business performance before and after a polyurethane foam producing company embarked on Max foam plant, which is a continuous machine for producing foam as a result of technology development. The study was designed to assess the performance of the company using questionnaire, interviews as well as data from secondary sources. The current productivity of the company (1996-to date) was found to be much higher than hitherto (1979-1996) when it employed the older method of polyurethane foam production ( the “box method”). The production rate per month, operating profit per month, operating profit per annum, the profit after tax, all increased tremendously by about 600%. Overall, the company achieved increased production, reduced wastage, high tonnage and reduced process and fugitive emissions. Strategies for maximizing the benefit of using the latest technology of production were therefore recommende

Study of the influence of xylene-based chemical Additive on crude oil flow properties and Paraffin deposition inhibition

Paraffin related problem appears through out the production process of nearly all kinds of crude oils all over the world. It also appears in the dewatering process and the long distance crude oil transportation. In Nigeria, operators spend millions of dollars each year to control the deposition of paraffin and to deal with other sand related problems. Expenditures of this magnitude obviously have a significant impact on profits. This paper introduces the latest research and development of a novel chemical additive for the control of paraffin deposit and the successful application on Nigerian oilfields. Results of cold spot and dynamic flow tests revealed the unique potential of the xylene-based formulation for achieving greater paraffin deposition efficiency, pour point depression and improved transport properties for a wide range of waxy hydrocarbon systems in comparison with other conventional paraffin deposit-control chemicals. The economic benefits and cost effectiveness of using this chemical for inhibiting wax deposition has been demonstrated in a field performance evaluation