| Abstrakt: |
The beehive kiln type is widely used for firing bricks and ceramics because it can process a large number of products in one firing process. However, some locations in the kiln have unstable temperatures causing the ineffective firing of bricks. The emissions released from this kiln have never been reported. This study aims to clarify these issues by monitoring and analyzing various parameters, e.g., temperature variations at different locations, firewood feeding times, and flue gas properties for a run over 16 days. Different firewood types are filled to increase the temperature from 50 to 150 °C in the drying stage, 150–650 °C in the pre-heating stage, and 650–1,000 °C in the firing stage, respectively. Finally, firewood feeding ceases to allow the cooldown of the kiln. Results show that in any stage, the main temperature fluctuations are caused by firewood feeding, leading to excessive use of firewood. This kiln achieves the emission standard for the flue gas analysis, except for the CO in the drying process since this stage needs low temperature to maintain the brick quality, resulting in incomplete combustion. However, in the pre-heating and firing phases, the CO decreases substantially, reaching the standard restriction. The maximum value of CO2, CO, NOX and SO2 is 16.45%, 2496 ppm, 30.2 ppm and 4.0 ppm, respectively. The firewood feeding must be strictly controlled during the drying stage for complete combustion. Overall, this investigation is beneficial for improving the economy and environmental friendliness of operating this kiln. [ABSTRACT FROM AUTHOR] |
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