음식물류폐기물의 에너지 잠재량은 2,206 천TOE 임에도 대부분 사료화와 퇴비화로 약 85.5%가 재활용 되고 있으며, 해당 시설에서 생산된 제품 중 사료화는 72%, 퇴비화는 61%가 무상판매 되고 있다. 이에 본 연구는 음식물류폐기물을 반탄화 반응을 이용하여 연료화하고자 한다. 하지만 음식 물류폐기물만 단독으로 연료화 할 경우 연료적 가치가 낮아짐을 예방하고자 하수슬러지를 일정 비율로 혼합하여 진행하였다. 음식물류폐기물과 하수슬러지의 혼합비율은 10:0, 8:2, 6:4, 5:5로 하였다. 실험 결과 혼합 비율에 상관없이 반응온도 240℃이상에서 함수율 10% 이하로 감소하는 것을 확인 할 수 있 었다. 고정탄소의 경우 반응온도가 높아질수록, 하수슬러지의 비율이 높아질수록 증가하였으며, 초기 1.1%에서 최대 약 36% 로(혼합비율 6:4, 반응온도 270℃) 측정 되었으며, 발열량의 경우 반응온도 24 0℃부터 고형연료제품기준인 3,000Kcal/Kg 이상에 만족하는 발열량을 나타내었으며, 초기시료보다 약 6 배 정도 증가한 발열량을 얻을 수 있었다. Van krevelen Diagram이 Lignite 범위까지 이동하였으며, 슬 러지 혼합비율이 높아질수록 높은 연료비와 5,500Kcal/kg 이하의 연소성지수를 얻을 수 있었다. 하수슬 러지 혼합 비율이 높아질수록 발열량은 감소하지만, 고정탄소 함량 증가, 연료비 개선 등으로 음식물류 폐기물만 단독 고형연료화 한 것 보다 연료로써의 품질이 좋아지는 것을 확인 할 수 있었다.

Dry Process(natural drying, hot-air drying, oil fry drying), optimized mixture ratio and the condition of carbonization was carried out in order to improve the product durability develop eco-friendly solid fuel mixing food waste and paper sludge. As a result of the experiment, oil fry drying process was the fastest method for drying food waste and paper sludge mixture that contains 80% water inside, and the optimized mixture ratio to minimize the generating concentration of chlorine gas against caloric value of mixture ratio was 7:3. Additionally proper temperature of product carbonization was about 200℃ and shown increasing product durability through the carbonization. Therefore, the pelletized solid fuel be shaped diameter around 0.5cm, length 2cm under which was pulverized and molded using 7:3 mixture of food waste, and paper sludge was the eco-friendly solid fuel possible to be industrialized which is consist of chlorine concentration of below 2.0wt% and the lowest caloric value of over 5,000kcal/kg. In conclusion, this developing manufacturing process of the solid fuel can be interpreted to contribute alternative energy development in accordance with low carbon and green growth era.

In this study, a lab-scale experiment was conducted to derive the optimal torrefaction conditions for upscaling food waste torrefaction to generate solid fuel. Basic characteristic analyses (a proximate analysis, elemental analysis, calorific value and thermogravimetric analysis) were conducted and further used to develop experimental conditions during upscaling. Based on the characteristics analysis, the experiments were conducted by varying the heating rates by 5, 10 and 15oC/min, varying the torrefaction temperature from 200 to 550oC at an interval of 50oC and varying the torrefaction residence time from 0 to 50 minutes at an interval of 10 minutes. The heating rates were varied and only carried out for the combustion experiments of the torrefied product at a temperature range of 50 to 800oC. The results show that the optimal torrefaction temperature and residence time of food waste torrefaction were 250 ~ 350oC and 30 ~ 40 minutes, respectively.