Modelling of a small scale palm fruit biomass-fired boiler

Abstract

This study developed a mathematical model for the operation of a small scale palm fruit biomass-fired autoclave boiler and validated the model  developed. These were with a view to providing an insight into the theoretical prediction of the boiler performance under different operating conditions  and to also serve as reference point for scaling up. Models were developed using fundamental equations that apply conservation laws and were validated  by comparing predicted results from theoretical combinations of the operating conditions with the experimental results obtained. The amount  of air required per kg of shell, fiber and EFB as calculated were 6.66, 5.98 and 6.27 kg, respectively. Therefore, 20% of the optimum air required were  introduced for all fuel combinations as excess air in order to achieve a better combustion process. Some of the values for predicted / experimental results  for steam temperature profile include: 154 / 156 °C; 158 / 150 °C; 166 / 159 °C; 149/ 161°C after 60 minutes firing time while some of the  predicted / experimental results for furnace core temperature profile after 60 minutes firing time include: 704 / 605 °C; 678 / 611°C; 595 / 613 °C; 650 /  640 °C; 637 / 640 °C etc. The predicted result obtained were in line with the experimental result as the result of the model validation showed that the  predicted and experimental values of average steam temperature and furnace core temperature compared well with overall deviation value of about 0.12  and 1.68%.