Heat Energy from Sunflower Residue

Abstract

ABSTRACT THE feasibility of using two forms of densified sunflower biomass as fuel in a commercially available, residential sized boiler unit was studied. Major concerns were efficiency, and fuel and ash handling problems. The heating value of the sunflower stalks was 13.9 (LHV) and for the sunflower hull pellets the value was 16.3 (LHV). Combustion air intake rate was controlled to determine its effect on these parameters. Short term tests using sunflower stalk briquets and hull pellets showed that both fuels would burn at acceptable efficiency levels but several problems were encountered with each. The sunflower stalk briquets burned with an average efficiency of 67%, and produced little smoke. The needed combustion air flow rate and the primary to secondary air ratio were easily provided by the boiler, and there was little difficulty in controlling the combustion rate. Sunflower stalk briquets were slow in igniting and contained a high percentage of ash. The sunflower hull pellets had a higher heat content and greater surface area than the stalk briquets. The main problems with the sunflower hull pellets were the low air intake rate necessary to prevent overheating and difficulty in supplying enough secondary combustion air to prevent smoking. The average combustion efficiency of the pellets was 62%. Ash produced by the pellets was only 3.6% compared to 10.8% from the briquets.