This study was performed to investigate the possibility of utilizing sewage sludge as a fuel. The drying characteristics of sewage sludge were examined by using vacuum evaporation and fry-drying technology in a batch-type rotary evaporator. In addition, the optimal drying conditions of sludge in the vacuum evaporator were investigated in terms of the vacuum pressure, temperature, and oil dosage ratio, etc. Experimental results showed that the moisture content in the sludge decreased with increases in oil/sewage sludge ratio and temperature. Dried sludge fuel (SDF) product could be obtained with on average less than 5% moisture content and a lower heating value of more than 4000 kcal/kg. Considering energy effi ciency, we suggest that the optimal operating condition for drying sludge is −450 mmHg of vacuum, a temperature of 100°C, a drying time of 90 min, and a sludge/oil ratio of 1:1. The SDF product was shaped as granules and fl uff-type particles. Evaluated from the perspective of the energy balance and economic considerations, this sludge drying system with vacuum fry drying could be used for effective sludge treatment and the production of SDF.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.