In case of domestic pyrolysis dry distillation gassification technology, it stays at the stage of its early introduction and development. Moreover, the companies possessed of this technology are limited to Japan and some countries in Europe, and domestic operative performance of this system is nominal, so there exist a lot of difficulties in securing its basic data. In addition, considering its operation and management, there happens a corrosion of metals by the production of corrosive gases in time of combustion of waste, and there arise a problem of occurrence of low temperature corrosion on exterior casing or gas ducts of a combustion chamber due to the high temperature corrosion around the burner of an incinerator, lowering the durability of an incinerator. Therefore, this study looked at the problems arising in time of incineration by understanding the characteristics of the pyrolysis dry distillation gassification incinerating facility, and did research on the improvement plan for durability of an incinerator for more economic, efficient waste incineration.
1996년부터 환경부에서 시행된 전국폐기물통계조사는 매 5년을 주기로 조사를 실시하며 폐기물의 종류별 발생 및 처리현황 파악 및 폐기물 발생원에 따른 발생원단위를 산정한다. 사업장 폐기물의 경우 올바로 시스템에 매년 실적보고를 하며 전국폐기물통계조사는 실적보고 자료와 별도의 추가 설문조사를 통해 사업장의 경제데이터를 확보한다. 제 5차 전국폐기물통계조사에서는 객관성 높은 통계 자료를 얻기 위해 모든 폐기물에 동일한 방법론을 적용했던 기존의 조사・분석 방법에서 사업장에 특성에 따른 조사를 실시하였고 SAS프로그램을 이용한 무응답 조정 가중치 산출, 캘리브레이션 가중치 산출, 변동계수 산출 등 통계적 기법을 추가하였다. 사업장 일반폐기물은 대기, 수질, 소음진동 등에서 규정하는 사업장에서 배출되는 배출시설계 폐기물과 배출시설계 외 1일 300 kg이상 배출하는 사업장 생활계폐기물(공사 및 작업관련 폐기물 5톤이상 포함)로 규정하고 있다. 본 연구에서는 배출시설계 폐기물과 사업장생활계폐기물이 포함된 사업장 일반폐기물 간의 발생원단위를 비교하였다. 향후 조사에서는 환경영향평가 등에 활용 가능하도록 배출시설계 폐기물의 경우 사업체 규모에 따라 나누어 발생원단위 산정을 하는 것이 필요하다고 사료된다. 또한 현재 경제데이터 조사방식인 임의조사의 한계를 보완하기 위해 추가 표본조사 실시를 권장하며, 장기적으로는 법 개정을 통해 올바로시스템 전수조사 방법을 제안한다.
The objective of this research was to estimate the greenhouse gas (GHG) emission factors for food, paper, and wood wastes through methane (CH4) flow analysis. The GHG emissions from a given amount of landfill waste depend on the carbon (C) flows in the waste: (1) carbon storage in landfills, (2) C in carbon dioxide (CO2) and CH4 generated in anaerobic waste decomposition, (3) C in CO2 and CH4 emitted to the atmosphere through vertical gas wells, (4) C in CO2 from CH4 oxidation through cover soils, and (5) C in CH4 emitted to the atmosphere through cover soils. This study reviews the literature on the ranges for DOCf (the fraction of degradable organic carbon that can decompose) and OX (oxidation factor) values of food, paper, and wood, with a particular focus on the role of lignin. There is an inverse relationship between lignin and the DOCf of paper and wood wastes. In this respect, the lignin content could be used as an abatement indicator for the DOCf of paper and wood. The literature review shows that the average DOCf values for food, paper, and wood were 0.72, 0.61, and 0.12, respectively. The country-specific DOCf value for wood (0.44) is significantly higher than the ranges reported in the literature, which implies that the country-specific DOCf for wood can overestimate GHG emissions compared to the DOCf obtained from the literature. The estimated GHG emissions factors were 1,055 kg-CO2e/ ton-wet waste for food, 1,367 kg-CO2e/ton-wet waste for paper, and 276 kg-CO2e/ton-wet waste for wood. Sensitivity analysis results showed that the most influential parameters were MCF (CH4 correction factor), DOCf, and OX. In order to reduce GHG emissions from landfill in Korea, landfill sites currently in operation should be converted from anaerobic to semi-aerobic.
Characteristics of the exhaust gas of a commercial scale (7.2 ton/day) municipal wastes incinerator with recirculation of its high temperature combustion gas were investigated. High temperature combustion gas made by incineration was entrained by an air jet and re-used for incineration. Air was preheated to 384-512oC and diluted to have an oxygen concentration of 16-17%. Incineration of municipal wastes with the preheated and diluted air made extremely uniform and stable flames. Concentrations of nitric oxide (NOx), carbon monoxide (CO), oxygen (O2), and carbon dioxide (CO2) in flue gas were measured at the boiler exit and the stack, simultaneously. Averaged concentrations of NOx and CO were reduced to 54.2 ppm and 3.1 ppm at the boiler exit and to 49.8 ppm and 6.0 ppm at the stack, respectively, at a reference oxygen concentration of 12% without any post treatment of NOx and when the averaged outlet temperature of the combustion chamber was 904oC. The measured NOx emission was only 29% of that of a conventional municipal incinerator. Simultaneous reduction of NOx and CO is significant. Averaged concentrations of O2 and CO2 were 9.7% and 8.6% at the boiler exit and 14.6% and 4.9% at the stack, respectively.
It is known that lowering of peak temperature of flame reduces NOx emission in combustion process. Low oxygenconcentration of diluted combustion air reduces peak flame temperature, but makes flame unstable. So increasing oftemperature of reactants is needed to enhance flame stability. Mixing of high temperature combustion gas with combustionair makes low oxygen concentration and increases air temperature simultaneously. Low oxygen concentration ofcombustion air reduces peak temperature of flame and increased air temperature makes flame stable by enhancement ofcombustion reaction. Special apparatus for recirculation of high temperature combustion gas should be needed, becausegeneral blower cannot be used to return the gas of almost 1,000oC. Air jet type recirculation apparatus has been developedand installed in a commercial scale of 7.2ton/day incinerator and estimated. Oxygen concentration and temperature ofair mixed with inhaled high temperature combustion gas by the apparatus are 16.24~17.78%, 384~512oC, respectively,in a steady state of incineration.
This study was conducted to provide the basic information to know reasonable method for the removal and treatment of municipal solid wastes(MSWs). MSWs four different sources(apartment, residence, commerce, office/industry) in Daegu city were collected, and bulk density, physical composition, moisture, combustible, ash, elements and heating values were investigated.
The values of bulk density were at range of 0.30~0.41ton/m3.
The percentages of foods, papers, vinyls/plastics, textiles, rubbers/leathers, metals and glasses/ceramics of wet muncipal solid wastes from three sources except office/industry were at range of 27.3~46.4%, 21.2~38.4%, 10.3~11.9%, 3.8~5.2%, 0.5~1.7%, 6.9~8.7% and 1.9~2.6% respectively. The percentages of papers, foods, vinyls/plastics, textiles, rubbers/leathers, metals and glasses/ceramics of dry muncipal solid wastes from three sources except office/industry were at range of 21.1~40.4%, 14.2~30.1%, 15.2~17.8%, 4.0~6.0%, 0.9~2.8%, 12.2~14.1% and 3.1~3.7% respectively.
The moisture contents of foods, woods, textiles and papers in wastes were at range of 65.7~76.2%, 34.6~50.0%, 22.2~44.8 and 30.6~44.4% respectively. The carbon contents of vinyls/plastics, rubbers/leathers, textiles, woods, papers and foods in wastes were at range of 75.88~79.87%, 58.24~70.74%, 45.23~51.63%, 42.29~45.58%, 40.19~48.4% and 25.86~36.25% respectively.
The low heating values of foods, papers, woods, textiles, rubbers/leathers and vinyls/plastics by Dulong's law were at range of 178~1,353kcal/kg, 770~1,660kcal/kg, 995~1,629kcal/kg, 2,133~2,432kcal/kg, 4,200~7,275 kcal/kg and 6,384~8,722kcal/kg respectively, and the high heating values of them were at range of 782~2,056 kcal/kg, 2,459~3,314kcal/kg, 3,056~3,592kcal/kg, 4,381~5,087kcal/kg, 5,005~8,066kcal/kg and 10,032~10,739 kcal/kg respectively.