Pentanol blending as an effective strategy to improve performance and reduce cenosphere emissions from heavy fuel oil combustion

Transitional sustainability with improved combustion and reduced emissions from heavy fuel oil (HFO) utilization in boilers, furnaces and marine engines can be achieved by blending methanol/ethanol. However, it leads to emulsions which pose techno-economic challenges regarding its production, surfactant cost, storage stability and uneven blend ratios. To address this challenge, this work proposes, for the first time, 1-pentanol as a blending agent to HFO. Results show that pentanol produces fully miscible mixtures up to 30% by wt. without co-solvent as well as greatly reduces HFO viscosity. Isolated droplet evaporation and combustion experiments at flame-like conditions are carried out considering three mixtures of pentanol in HFO: 5, 10 and 25%wt. (P5, P10 and P25, respectively). Novel and detailed results describing the effect of blending are obtained across the entire consumption history of HFO, namely, liquid evaporation, cenosphere morphology using SEM-EDX and its subsequent combustion. Under both reducing and oxidizing conditions, a major amount of pentanol preferentially evaporates during the heat-up period, inducing violent micro-explosions. This phenomenon causes a major reduction in the liquid lifetime of HFO (~10–18% with P10), reducing also the ignition delay time (~15–20% with P10). The remaining amount of pentanol affects the pyrolysis+polymerization stage, thereby generating cenospheres which are smaller in size (~31.3% reduction with P10 in 0% O 2 ) and have similar external structures but with thinner and more porous walls, and hence their burning times are also reduced (~6.3–24.7% with P10). These positive impacts suggest that blending HFO with 10% pentanol, which has promising potential as next generation bio-alcohol, may constitute an alternative strategy until the HFO sector is decarbonized.