Refuse-derived fuel (RDF) produced using municipal solid waste was pyrolyzed to produce RDF char. For the first time, the RDF char was used to remove aqueous copper, a representative heavy metal water pollutant. Activation of the RDF char using steam and KOH treatments was performed to change the specific surface area, pore volume, and the metal cation quantity of the char. N2 sorption, Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and Fourier transform infrared spectroscopy were used to characterize the char. The optimum pH for copper removal was shown to be 5.5, and the steam-treated char displayed the best copper removal capability. Ion exchange between copper ions and alkali/alkaline metal cations was the most important mechanism of copper removal by RDF char, followed by adsorption on functional groups existing on the char surface. The copper adsorption behavior was represented well by a pseudo-second-order kinetics model and the Langmuir isotherm. The maximum copper removal capacity was determined to be 38.17 mg/g, which is larger than those of other low-cost char adsorbents reported previously.

Quality design methodologies have received constituent attention from a number of researchers and practitioners for more than twenty years. Specially, the quality design for drug products must be carefully considered because of the hazards involved in the

세계의 모든 나라가 화석연료를 대체하는 태양광, 풍력 등의 그린에너지 기술개발에 주력하고 있으며, 한편으로는 에너지의 효율제고 및 재생을 위하여 폐기물로부터의 자원순환을 이룩하는 폐기에너지 회수에도 많은 노력을 기울이고 있다. 그 하나의 방편이 버려지는 쓰레기에서 에너지를 회수하는 고형재생연료인 RDF(생활폐기물 고형연료 제품, Refuse Derived Fuel) 생산이다. 우리나라에서는 유일하게 강원도 원주시에서 하루 80톤을 생산하고 있으며 아직은 기술도입 초기단계에 있는 가연성폐기물의 연료화 기술이다. RDF의 특성은 불연성 성분이 제거된 일반 가연물을 분쇄하여 압출성형 가공한 펠릿형상의 고체연료로서의 열적 특성이 우수하나 화재안전 측면에서는 제조 및 취급공정에서의 일반적인 가연물 화재위험성을 가지고 있고, 저장과정에서는 축열발열에 의한 자연발화 위험성이 상존하며, 저장형태, 특히 사이로의 경우 구조특성으로 인하여 화재진압도 쉽지않다. 본 논문에서는 일본의 RDF 화재사례를 중심으로 그 화재 위험 특성과 안전대책을 고찰하고자 한다.

매립지에서 발생하는 매립가스는 악취를 발생시켜 주변지역 대기환경을 저해하고 있다. 매립가스의 주성분은 온실가스인 이산화탄소(CO2)와 메탄가스(CH4)로 구성되어 있어, 바이오에너지와 같은 대체에너지 생산 기술 등의 연구에 활용되고 있다. 본 연구에서는 가스화 공정에서 발생하는 RDF char를 이용하여 CO2/CH4 개질 반응을 통해 생성되는 합성가스의 주성분인 CO, H2의 생성 특성에 대해 연구하였다. 1023∼1173K의 온도에서 CH4/CO2 ratio는 1.3으로 고정하여 혼합된 CO2와 CH4를 RDF char와 반응시켜 생성되는 H2와 CO의 변화를 측정하였다. 실험 결과에는 반응 온도가 1123K일 때 SUS bed의 CO2 전환율은 3.2%로 나타났으며, 반면 RDF char에서의 CO2 전환율은 81.7%로 나타났다. 이러한 실험결과로 RDF char는 CO2 개질반응에 촉매 역할을 하는 것으로 판단된다. 반응 후 RDF char 성분 분석 결과에 따라 함량이 높은 CaO는 반응전과 후 비슷한 결과를 나타났고 CO2 전환에 영향을 주지 않아 촉매 역할을 하는 Fe2O3나 TiO2에 의한 것으로 판단된다. 산소가 없는 경우에 RDF char에 의한 CO2와 CH4 개질 반응은 온도 증가에 따라 CO2 전환율은 45.3%(1023K)에서 83.16%(1173K)로 증가하였고 CH4 전환율은 10.2%(1023K)에서 27.0%(1173K)로 증가하였다. 또한 산소가 있는 경우는 산소 없는 경우보다 CH4 전환율은 1173K에서 27.0%에서 41.1%로 증가하고 발생가스의 H2 비율은 15.8%에서 22.3%로 증가한 것으로 나타났다. 이는 RDF char에 의해 메탄과 이산화탄소 개질 반응에 Reforming reaction과 Reverse WG shift reaction, Boudouard reaction, Reverse WG shift reaction에 의한 영향을 받는 것으로 판단된다.

The objective of this study was to evaluate the microwave drying characteristics of mixtures of chemical wastewater sludge (70~90%) and anthracite coal (10~30%) with respect to physical and economic factors such as mass, volume reduction, moisture content, drying rate and heating value when the wastes were dried at different weight mixing ratio and for different microwave irradiation time. The drying process were carried out in a microwave oven, the combined drying process with a 2,450 MHz frequency and 1 kW of power. Maximum dry rates per unit area on the microwave drying of mixtures with chemical wastewater sludge and anthracite coal were 35.5 kg H2O/m2·hr for Cs90-Ac10; 40.1 kg H2O/m2·hr for Cs80-Ac20 and 35.0 kg H2O/m2·hr for Cs70-Ac30. The result clearly indicated that moisture can be effectively and inexpensively removed from the wastes through use of the microwave drying process.

After analyzing of heating value of four kinds of RDF, the RDF-D has the highest heating value, was chosen to be mixed with carbonized sludge by different ratio. The 85%：15% ratio, which has the highest efficiency, was analyzed with thermogravimetric and pyrolysis kinetics. Applying of Kissinger method, activation energy was obtained from slope which is calculated from relation of ln(β/T2 m) and 1/Tm. The kinetic parameters obtained from Kissinger method were 46.06 kJ/mol of RDF, 55.99 kJ/mol of carbonized sludge and 40.68 kJ/mol of mixture of RDF and carbonized sludge. The mixture of RDF and carbonized sludge has the lowest activation energy and frequency factor, during thermal decomposition reaction it has the slowest reaction rate and needs the lowest energy. Although activation energy with pyrolysis of RDF was irregularly scattered, it showed that activation energy was stabilized by co-pyrolysis of RDF and additives(Carbonized Sludge).

폐기물 고형연료(RDF : Refuse-Derived Fuel) 또는 고형연료제품(SRF : Solid Refuse Fuel)은 가연성 고체폐기물을 분쇄한 후에 선별 및 건조 과정을 거쳐서 제조되는 성형 또는 비성형 고체연료로서 회석연료의 대체에너지로 이용이 가능하고, 일반적인 소각 방법에 비하여 수송성, 저장성, 연소 안정성이 우수하여 소각시설의 열이용에 따르는 많은 문제점을 해소할 수 있는 장점을 가지고 있다. 본 연구에서는 RDF에 대한 연소 특성을 파악하기 위한 목적으로 실험실 규모의 연속식 및 회분식 연소 장치를 이용하여, RDF의 조성과 연소 조건에 따른 비교실험이 수행되었다. RDF 연소 특성실험에 사용되는 RDF 시료는 모두 6 종류의 원료와 실험실 규모의 압착 기구를 이용하여 3종류 형태(Powder, Chip, Plate)로 제조되었으며, RDF 연소 특성 비교 실험은 100 ~ 300 g-RDF/시간의 처리 용량을 가진 연속식의 실험실 규모 연소 장치와 길이가 600 mm인 연소로에 장착된 내경 70 mm의 석영 튜브를 이용하는 회분식의 RDF 연소 장치를 이용하여 수행하였다. 주요한 실험 결과를 살펴보면 우선 2 ~ 6 g/개 범위의 무게를 가진 RDF 시료는 대부분이 5 분 정도의 시간내에서 연소가 종료되었으며, CO는 100 ~ 300 ppm (12% O₂), NO는 200 ppm (12% O₂) 이하의 배출 농도를 나타냈다. RDF 제조용 원료로 사용된 PE 및 PP의 함량이 높아질수록 CO 배출 농도는 급격히 증가하며, O₂ 농도는 PE 및 PP의 함량이 증가할수록 감소하는 경향을 보인다. 또한 NO 및 CO₂의 경우는 PE 및 PP의 함량에 따른 배출농도의 변화가 상대적으로 작게 나타났으며, RDF 시료중의 염소 성분 함량이 일정한 조건에서는 흡수제로 사용되는 Ca(OH)₂의 투입량이 많아질수록 바닥회재 중의 염소 함량이 증가하였다.

Over the past few decades, many scientists and environmental activists emphasized the importance of sustainable society and warned the global warming. As one of efforts to achieve the sustainable society and maintain no more of global warming, the RDF (Refuse Derived Fuel) production from domestic solid is taken into account seriously in Daejeon, Korea. Currently, the pay per throw system is active from 1995 and is quite stabilized. Recyclable wastes such as metal scraps, glass, papers, and fibers like clothes should be discarded separately and not be mixed with other types of waste being disposed of eventually. To assess the potential for the conversion of domestic solid waste into a heat source, i.e., RDF, the proximate analysis, the classification into 10 components, and the calculation of heat value based on the result of the elemental analysis were performed. Based on the preceding analysis, the domestic solid waste produced daily in Daejeon, Korea has a potential for conversion into an alternative energy source, RDF in technical aspect. Proper blending of combustibles, however, is necessary to enhance the heating value of RDF being produced and to be more viable in economic aspect.

The refuse derived fuel (RDF) is available for renewable energy which can use alternative fuel to utilize recycling municipal solid waste (MSW). The RDF plant where can produce 100 ton/month of RDF, the largest manufacturing plant in Korea so far, were investigated in this study. The actual operated RDF yield showed 21.7% that was lower than expected yield; originally designed value was 25.0% in this plant. The cause of these results was that difference between physicochemical properties of MSW applied this plant originally and actual incoming it. The MSW affected to make separation efficiency of MBT process decreasing. It led to reduce amount of combustible material which needed for RDF after separating process. The each element of facilities was modified; decreasing width of the blade of a shadder from 110 mm to 63 mm, reducing the size hool of trommel screen to possible separating under 40 mm of MSW, increasing heat capacity of dryer from 2,000 Gcal/hr to 2,500 Gcal/hr, and conveyor type changed to prevent path MSW away during moving into each process and so on. After modifying facilities, got more combustible materials which were once lost and RDF yield increased to 30.9%. Whereas, low heating value of RDF was 4,725 kcal/kg, 0.8% of chlorine on average and other parameters were satisfied with domestic standard of RDF regardless of modifying MBT facilities.

The waste treatment cost and energy production benefit of Wonju city RDF plant, the first RDF manufacturing plant in Korea, were investigated in this study. All plant operation data, like total weight of received wastes, produced RDF and separated rejects in processes have been fully recorded for mass balance calculation of the plant. Also all consumed oil and electricity have been recorded for energy balance calculation. The results showed that the waste treatment cost not included the RDF sales price of 25,000 won/ton-RDF was 139,316 won/ton-MSW and it went down to 128,640 won when included the RDF price in 2011. Produced RDF was 42.7% of total received waste in weight. Three components analysis by mass balance calculation of total received waste showed that Wonju city's MSW was 34.0% of combustible, 35.0% of water and 31% of incombustible respectively. Energy effect was found that total amount of produced energy was about 4 times more than that of consumed energy. Analysis data for 5 years since 2007 were summarized and shown in this study.