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Effect of additives on the ash element from combustion of palm fiber and shell

2020 , J Nor Ruwaida , M Dewika , S Shahidana , M Rashid , Abd Halim Md Ali , M P Khairunnisa , M R Ammar , Zahiruddin S. , Sara Yasina Yusuf

Palm fibre and shell (F&S) are commonly used in the combustion process to produce steam and electricity in palm oil mills in Malaysia. Unfortunately, the combustion process releases various types of elements that tends to react with each other contributing to operational and environmental issues. Thus, this motivated, a study to evaluate the concentration of the elements such as C, O, Si, K, and Al in the ash with the presence of two combustion additive which are Kaolin and PreKotTM. The study was performed by simulating the industrial combustion in a laboratory-scale fluidised-bed reactor with addition of the additives at 8% ratio from the 40 g total weight of each sample at 800°C with the supply of 50% excess air at 1.24 L/min air flow. The ash residue were investigated for elemental composition on the ash surface. Interestingly, the study showed that the concentration of the element on the ash surface increased with the addition of additives especially at a 50% ratio of Kaolin and PreKotTM. The higher concentration of the element on the ash surface indicates the reduction of fine particulate. Hence, the study revealed that addition of Kaolin & PrekotTM in combustion process has a promising future not only within palm oil industry but also other industry.

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Performance evaluation of a retrofitted multi-cyclone using computational fluid dynamic

2020 , M Dewika , M Rashid , C M Hasrizam , M P Khairunnisa , J Norruwaida , Sara Yasina Yusuf

Multi-cyclone is widely used in industries as air pollution control device due to several advantages over other available separation units such as its low capital, operating, and maintenance cost and as well as its usability under a wide range of operational conditions. However, it is merely a pre-cleaner as it is inefficient in collecting fine particulate especially, particulate matter with size less than 10 µm (PM₁₀) and below. Hence a simple, cost-effective retrofit on a Conventional Multi-cyclone (CMC) with the motivation of increasing its overall performance on fine particulate emission control was carried out. The retrofit was performed by creating higher negative pressure inside the dust hopper of the CMC by extracting 10% and 24% from the total volumetric airflow rate of the unit with the means of an external Induced Draft Fan. The Computational Fluid Dynamics (CFD) with Reynold Stress Model (RSM) turbulence model was performed and validated using experimental data to gain a better understanding in pressure distribution, velocity profile and particulate movement between the CMC and the Retrofitted Multi-cyclone (RMC). The CFD results show deviation between 0% to 8% for pressure at inlet and outlet of cyclone compared to the experimental results. In addition, CFD results depict that the RMC has higher pressure at the inlet and lower pressure inside dust hopper of CMC, which cause the finer particle to be pulled in through suction outlet. Also, the emission of fine particulate is reduced in RMC by 9% to 16%. compared to the CMC. Moreover, the phenomena at the suction duct can be clearly explained with the usage of CFD. The finding suggests that a simple, cost-effective retrofit at the multi-cyclone has increased the overall performance in the fine particulate collection, and the understanding of the phenomena could be enhanced by the CFD.