In recent years, burning joss paper in temple furnaces has been noticed to be a significant cause for particulate emissions in Asia, especially in Taiwan. This study investigates feasible options of air pollution control devices (APCD) for joss paper furnaces in temples, and used a 40 kg/hr joss paper furnace for testing. This paper examined particulate removal efficiencies of two options: a bag house (capacity 30 m3/min at 108°C) and a wet scrubber (capacity 40 m3/min at 150°C).
The results indicate that particulate matters (PM) in the diluted flue gas at the bag-house inlet were 76.6 ± 32.7 mg/Nm3 (average ± standard deviation), and those at the outlet of the bag-house could be reduced to as low as 0.55 ± 1.28 mg/Nm3. An average PM removal efficiency of 99.3% could be obtained with a filtration speed of approximately 2.0 m/min evaluated at 108°C. The wet scrubber removed approximately 70% of PM, with scrubbing intensities higher than 4.0 L/m2.s across the scrubber cross-section. For the duration of the experiment, no visual white smoke (water mist) was observed at the exit of the wet scrubber with a combustion rate of 16 kg/hr of joss paper, and the scrubbing water temperature was automatically sustained at lower than 61°C. The study concluded that both bag filtration and wet scrubbing are suitable techniques to control particulate emission from joss paper furnaces in Taiwanese temples. The bag filtration technique, while achieving higher efficiencies than the wet scrubbing technique, requires more space and cost. Examinations of bottom and fly ashes of combusted joss paper with XRD (X-Ray Diffraction) revealed the presence of calcium oxide in the fly ash, while certain metals were found in the bottom ash.