Powering shuttle kilns with compressed biomethane gas for the Thai ceramic industry

Abstract

The objective of this research is to substitute compressed biomethane gas (CBG) for liquefied petroleum gas (LPG) for use in industrial ceramic kilns. This is for both environmental and economic reasons. In Thailand, the ceramic industry employs directly and indirectly over 75,000 people mostly in Saraburi and Nakhon Lampang. It generates annual exports in excess of 30,000 million baht (approximately $910 million US). In 2014, it used 577,000tons of LPG a fossil fuel. Thailand has the potential to produce renewable biomethane, from agricultural waste, in quantities to meet this demand.Small-scale ceramic kilns use two types of burners, a rocket type and a shower type. A mixing nozzle injects the fuel into the burner. This creates a natural draft which entrains the combustion air and both air and fuel exit at the burner head where ignition occurs. It is not possible to directly substitute CBG for LPG without making physical changes to these nozzles and adjusting the flow parameters. This research outlines a methodology for adapting the burners for CBG and experimentally verifying the predictions. Flame stability, temperature, emissions, and efficiency were measured and were equivalent to the LPG flames. Finally, the modified burners were tested inside a 0.1m3 shuttle ceramic kiln and used to fire greenware. It is estimated that a cost savings of up to 30% can be obtained using CBG, with a payback period of a little over three and a half years, factoring in the cost of the changeover.