Expanded graphite (EG) was prepared using a drying process for application as an oil-adsorbent: the morphology, expansion volume, and oil absorption capacity of the EG were investigated. The expanded volume of the EG increased with an increasing reaction time and heat treatment temperature. The oil adsorption capacity of the EG was 45 g of n-dodecane per 1 g of EG. It is noted that the drying process of EG is a useful technique for a new oil-adsorbent.

This research is a basic researching process for producing solid fuel that mixing paper sludge and Heat Transfer Medium Oil. Under the presence of Heat Transfer Medium Oil, paper sludge is heated and dried with home appliance microwave for comparing drying efficiency and energy efficiency of different types of drying method. As a result, Heat Transfer Medium Oil and paper mixing case of drying method, OMD, is the most efficient way to shorten the time for evaporating moisture in the paper sludge. In addition, heat transfer effect and density is increased with adding Heat Transfer Medium Oil by microwave. Future more, OMD's energy cost for evaporating whole moisture is 78% cheaper than MD. Also, OMD process shows the best energy efficiency with comparing other process. Evaporation rate of paper sludge evaporation process with microwave is 11.66% increased by adding Heat Transfer Medium Oil 150g. Preheating Heat Transfer Medium Oil or improving different ways injecting Heat Transfer Medium Oil is a good way to increase a rate of initiative moisture evaporation process.

The effect of mixed oil on the drying characteristics of sewage sludge in oil vacuum evaporation systems was studied. The experimental results showed that the drying rate with cooking oil was faster than that with refined oil due to the difference of thermal conductivity and composition of mixed oil. However, the heating value of all dried sludge was enhanced and the moisture content was below 1% due to penetration of oil into the microbial cells in sludge during the drying procedure. TGA analysis of sludge mixed with the refined oil, which had a higher volatility, showed the slope of the primary falling period was sharply declined. The result of DTA analysis also showed that the first peak was higher than the second peak and corresponded with the phenomena observed in the TGA analysis. In the DTA analysis, the temperature of the primary peak and the secondary peak of dried sludge were comparatively lower than those of raw sludge. Therefore, mixed oil could decrease the self-ignition temperature in an oil-sludge mixing system. In case of waste cooking oil, the TGA and DTA results showed similar results to those of raw sludge, but the DTA results showed that the secondary peaks of dried sludge were narrower and sharper than those of raw sludge. Overall, mixing oil could be a principal factor in controlling the drying efficiency and thermal properties of sludge-derived fuel in oil vacuum evaporation systems.

This study was performed to evaluate the drying characteristics of food waste in oil vacuum evaporation system withdrying conditions and composition of food waste. The food waste was collected and separated into 4 categories such asvegetables, fruits, grain (rice), meats and others. which composition were 41.9%, 26.7%, 2.8%, 25.5% and 0.4%,respectively. Each food waste separated was dried and compared its characteristics in the same condition of vacuumpressure (−450mmHg), temperature (110oC) and mixing ratio (oil:food waste=1:1) for 90min of drying period. Theexperimental results showed that the moisture contents of dried vegetables, fruits and meats were less than 10%. Howeverthe grain was hard to be dried which moisture content was much high as 24.5%. This high value of the grain was thoughtdue to the viscosity of grain which prohibit oil penetration and water vaporization during drying process. In order tocompare drying characteristics with operating parameters, vacuum pressure, temperature and mixing oil type were changed.The operating temperature and vacuum pressure were major sensitive parameters. As the temperature increase and thepressure lower, the drying rate of food waste was increased and its efficiency was also improved. Especially, the moisturecontent of dried food waste was lower than 5% which was satisfied SRF standard 10% at the temperature over 110oC.Compared the effect of mixing oil type, waste cooking oil was more effective than refined oil in viewpoint of dryingefficiency. However, there is no difference of drying efficiency between fresh and waste cooking oil.

The amount of sewage treatment has been increasing year by year as the small and medium sized cities grow in Korea. Besides, the treatment of sludge has been more significant owing to the total ban on disposal of organic sludge in a landfill since April 2004 and ocean dumping of organic waste since December 2013. In this research, we studied the drying characteristics of sewage sludge by indirect heating device using thermal oil. The indirect heating device operated in a batch for 16 hours according to the variation of drying temperature between 100 and 200oC and the initial input weight of each type of sewage sludge was equally 60 kg. As a result, the moisture content in raw, excess and mixed sludge became lower than 10% under 14 hours at 160oC. The average water loss rate of raw, excess and mixed sludge is 0.436 g-wet/ min, 0.362 g-wet/min and 0.367 g-wet/min respectively at this stage. Therefore, the raw sludge can be dried well, using indirect heating device in sewage treatment plant. Also, it is better to dry raw sludge or excess sludge alone than mixed sludge because each type of sludge does not make synergistic effect but counter effect when they are together.

The drying and fuel technologies for sewage sludge have been developed due to the prohibition of ocean dumping and new renewable portfolio standard. This study was performed to enhance the quality of sludge derived fuel and compare drying characteristics for thickened and digested sewage sludge at different temperature, pressure and mixing oil conditions in oil vacuum evaporation system. In addition to investigate calorific value and characteristic analysis of dried sludge. The thickened and digested sludge used in this study were taken from municipal sewage treatment plant and coagulated using polymer (C-310P) in laboratory. The drying rate was increased with temperature and degree of vacuum and it was 25 mL/kg-sludge·min at 110oC and –450 mmHg. The moisture content of dried sludge products showed very low within 1% in the range of 0.4 ~ 0.8%. The evaporation rate of thickened sludge was lower than digested sludge and the constant evaporation period was also shorter. Compared the effect of waste cooking oil and refined waste petroleum oil on drying efficiency, the waste cooking oil showed more effective than refined oil in evaporation rate and drying time. The carbon and hydrogen contents of dried sludge with refined oil were higher than waste cooking oil. The low heating value of thickened dried sludge was higher than digested dried sludge about 400 kcal/kg and both of dried sludge showed high calorific value more than 4,000 kcal/kg.