Department: Agricultural And Bio-resources Engineering
Ogbuagu, N. J;
Ndirika, V. I. O
This study modelled and optimized the performance parameters of hydraulic press briquetting machine for production of briquettes from biomass waste. This technique is a profitable approach for curbing the environmental degradation constituted by these wastes due to indiscriminate disposal. Converting these wastes into briquettes is an age long technology that has ensured the use of processed biomass wastes in energy application systems. Hydraulic press briquetting machine being one of the most adopted machine for briquette production has not been fully explored in terms of its performance. The intention of the research work is therefore to develop mathematical models for predicting the performance parameters of hydraulic briquetting operation for biomass wastes through selection of various performance parameters and also optimize the process variables for production of high quality briquette.
The mathematical models were developed using dimensional analysis (Buckingham pi theorem) and the relevant parameters for the production of good quality briquettes were optimized using multiple regression analysis at three factor interaction of the process variables to obtain variables for optimum (maximum) briquette quality. The formulated models were verified and validated with established experimental data obtained from 5ton C-frame hydraulic briquetting machine. For the model validation and other experimental analysis, five biomass waste namely Stool wood sawdust, Gmelina sawdust, Mahogany sawdust, Oil bean wood sawdust and Rice husk were utilized. The performance parameters of the machine considered were; output capacity, quantity of damaged briquettes, production efficiency and bulk density of the briquettes. Further analysis on the effect of pressure and particle size on the physical properties of the briquettes were also investigated.
The theoretically predicted results and those obtained experimentally were compared and found to have coefficient of correlation (R) value of 0.99, 0.96 and 0.92 for output capacity, damaged briquettes and production efficiency models respectively. Bulk density model for each of the material used also showed high R value of 0.99, 0.99, 0.96, 0.98 and 0.98 for stool wood, Gmelina, Mahogany, oil bean wood and Rice husk respectively. The result obtained from the optimization revealed briquette density of 0.8050 g/cm3 was obtained at 6% binder, 315μm particle size and at 22bar. At this density, ash content, volatile matter, fixed carbon and calorific values of the briquettes are 1.05%, 81.84%, 0.31% and 23559kJ respectively. Fourier transform infrared spectroscopic analysis on the optimized briquette samples of oil bean sawdust and rice husk show the biomass materials belong to carboxylic functional group. Comparison of the calorific values of the optimized briquettes of oil bean wood sawdust and rice husk with that of the raw material also showed 3.5% and 54% increase respectively. The research also found out that effect of particle size on bulk density has significant at <1% probability for all the materials except Oil bean wood sawdust. The levels of pressure studied also has significant at probability level of <5% for the materials except Stool wood sawdust. This research is an advancement in briquette production and research findings can help in energy policy on the environment.