Combustion and emission characteristics of a reprocessed used lubricating oil as a renewable fuel for boiler cold start-up operation.

This paper investigated the combustion and emission characteristics of a reprocessed used lubricating oil (RULO) with a pilot combustion test furnace to assess the possibility for using it as a fuel for boiler cold start-up operation. Results were compared with those of a by-product fuel oil (BFO) presently used in the power plant. Fuel analysis and testing showed that both oils had similar fuel properties, but RULO represented less reactivity and larger sprayed particle diameter than BFO. The cold start-up combustion tests revealed that RULO was ignited later and furnace exit temperatures was higher in RULO combustion, compared to those in BFO combustion. NOx emission in RULO combustion was about 10 ppm higher due to the higher fuel-N, and particulate emissions, thought to be agglomerated unburned carbonaceous particles, were severer in RULO combustion test than BFO combustion test. The relative comparisons between two fuel oils would provide a basic information for substituting an existing fuel oil to a renewable fuel oil during the start-up operation of the coal-fired power plant. • Fuel characteristics of a reprocessed used lubricating oil (RULO) was investigated. • Combustion characteristics of RULO were compared to those of by-product fuel oil (BFO). • RULO exhibited a reasonable combustion performance, compared to BFO. • Particulate emissions were severe during the RULO cold combustion test. [ABSTRACT FROM AUTHOR]