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        검색결과 62

        41.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        This paper was conducted experimental work to energy recovery and syngas production using a pilot scale fixed bed gasification process of solid waste. The temperature of gasifier bottom section was the highest at about 522 ~ 808oC. The syngas composition was contained CO 10.0 ~ 11.4%, H2 8.4 ~ 11.3%, CH4 3.7 ~ 3.9%, CnHm 3.3 ~ 4.3% with lower heating value 1,500 kcal/Nm3. About 68.8% of the waste and the air energy is converted to syngas. Approximately 8.4% is lost in heat of heat exchanger and cleaning process and about 0.8% of the heat energy is recycled into the gasifier in the form of preheated air. The electric power output rate was found to range 10.5 to 12.5 kW.
        42.
        2015.07 KCI 등재 서비스 종료(열람 제한)
        Waste electrical and electronic equipment (WEEE) has been received much attention recently due to rapid changes in materials and shorter replacement of consumer products. Most of WEEEs are collected and recycled at the designated recycling centers in Korea, and final residues after recycling, sorting and shredding them to separate valuable and recyclable parts in series are left as forms of shredded plastic mixtures, which would be a problem to be resolved. By further plastics separation the polyurethane foams are mostly remained and becomes waste to be treated by appropriate methods. Gasification to produce syngas and incineration to recover energy for such polyurethane foam waste could be utilized instead landfill presently treated. In this study the experiment was conducted to evaluate such performance characteristics of thermal processes. Pelletized solid refuse fuel (SRF) was fabricated to feed into the test furnace even though it was light with low density. Thermogravimetric analysis, proximate analysis and higher heating value were made. During gasification and incineration, gas composition with gaseous pollutants were measured. Due to nitrogen content in polyurethane, nitrogen containing gaseous substances such as NH3 and HCN were observed with varying equivalent air ratios (ERs). The assessment of polyurethane waste foam to energy using incineration and gasification was made with finding out the optimal condition of air injection to emit less pollutants in both operations. Produced syngas could be utilized as energy fuels by lowering pollutants emission.
        43.
        2015.07 KCI 등재 서비스 종료(열람 제한)
        Nitrogen oxide (NOx) is one of air pollutants generated from the combustion of fuels, causing serious environmental problems. A novel externally oscillated staged combustion for RPF syngas was proposed in this work. The staged combustion could reduce NOx by the fuel-rich state combustion, while the external oscillation could achieve complete burn-out by stabilizing the flame. It also improved combustibility with an acceleration of the mass and heat momentum transfer. Parametric studies were achieved for the NOx reduction characteristics on the air staging and fuel staging in each case of with or without external oscillation. For the case of without oscillation, NOx reduction rate for the fuel staging had higher value as 75% than air staging as 67%. However, an application of external oscillation for both cases gives higher NOx reduction rate of 79%. The optimal condition for the oscillated fuel staging was that the air ratio in main burning zone, reburning zone and burnout zone were 1.1, 0.6 and 1.15, respectively, having 200 Hz of external oscillation.
        44.
        2015.05 서비스 종료(열람 제한)
        We carried out to investigate of CO2 reaction mechanism in oxy gasification reaction field. Capacity of gasification system is 0.5ton/day and that consists of feeder, gasification reactor assembled ash melting function, multi cyclone, wet scrubber, combustion chamber, heat exchanger, bag filter, ID fan and noncatalyst (steam reformer)/catalyst reformer. Gasification temperature was about 1,400~1,450℃ and RPF was used as a input material. We confirmed to possibility of Boudouard Reaction at the oxy gasification system. Boudouard Reaction is a reaction between carbon(soot) and carbon monoxide in the reaction field. We can find that the more Boudouard Reaction, the more residence time. For optimal reforming conditions such as temperature, amount of steam and residential time were investigated. It can be acquired that conditions of 45% H2 concentration and 3.0 H2/CO ratio in non-catalyst syngas reforming test and conditions of 60% H2 and 35% CO2 concentration in catalyst syngas reforming test.
        45.
        2015.01 KCI 등재 서비스 종료(열람 제한)
        Recently, the energy supply uses mostly fossil fuels such as coal, petroleum, natural gas etc... however, they are limited and they present an issue for the environment. Biomass derived energy is considered promising for reducing the emissions of CO2, the significant contributor to global warming. Also it can be converted to various forms of energy through thermochemical conversion processes. In this study, a screw gasifier has been engineered for wood biomass gasification. Waste wood chip was used as biomass and the producer gas, tar; char were then achieved by gasification in the presence of CO2. The results showed that with the increase of the gasification temperature, the producer gas increased and the tar decreased. Also, due to thermal cracking, the light tar increased by the decomposition of the gravimetric tar. And a development of char pore structure was confirmed by SEM. The gasification of biomass in the presence of CO2 at 800oC produced an increase in the concentration of carbon monoxide according to the Boudoudard reaction and an increase in the char pore surface as well as its adsorption capacity. Thus the biomass gasification in the presence of CO2 was confirmed to be effective for the production of CO and the development of char.
        46.
        2014.06 KCI 등재 서비스 종료(열람 제한)
        The present research examined the technological trends in optimizing the gasification of waste. Generally, when the percentage of impurities in waste is high, the energy density is low. High-temperature and high-pressure steam is difficult to obtain during energy recovery in incineration. Therefore, the energy recovery rate is low. However, if reaction conditions were optimized in gasification technology, it would be possible to produce synthetic gas with a high percentage of CO and H2. With regard to synthetic gas, there are many different types of energy recovery (steam turbines, gas turbines, gas engines) other than incineration, and it is possible to improve the recovery ratio through gas cleaning. Technologies that have the potential to optimize gasification in each phase were studied. With regard to domestic industry, optimization technology should be applied when planning and operating waste gasification.
        47.
        2014.04 KCI 등재 서비스 종료(열람 제한)
        In this study, the waste gasification gas was co-fired with LNG and water electrolysis gas (or stoichiometrically well-mixed hydrogen oxygen gas) in order to see the change of flame characteristics compared to the standard case of wellknown LNG flame. In detail, a numerical study was made to figure out the fundamental combustion characteristics ofthe waste produced gas blended LNG or hydrogen-oxygen mixture gas flame in an existing industrial LNG combustor.As a preliminary study, the mixture of 70% synthetic gas blended with 30% LNG or hydrogen-oxygen mixture gas wascompared with pure LNG fuel with maintaining the same total input of heating value. Especially, the reason to includethe hydrogen-oxygen mixture gas, that is, the mixture of H2 and 1/2 O2, as a fuel is following:the hydrogen-oxygenmixture gas has a rather high heating value since it does not need air as oxidizer, which consists of 79% N2 as inertmaterial. The result shows that the case of mixture fuel with LNG exhibits more broadening flame shape than the 100%LNG flame. Further, it is observed that there is a phenomenon like a disappearance of CTRZ (Central ToroidalRecirculation Zone) and flame extinction showing partial lift-off of flame around strong swirl flow near burner. This kindof observation appeared in the case of blended fuel mixture is considered probably due to the increased effect of velocityand turbulence stress caused by the mass increase by the addition of low calorific fuel. However, the case of mixturefuel with hydrogen-oxygen mixture gas and water vapor does not show any flame instability phenomenon due to increasedflow rate as in LNG case.
        48.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        This research performed physico-chemical analysis of MSW(municipal solid waste) for design and operation ofgasification generation system. The MSW sample was analyzed by proximate, ultimate, heat value method and sampledeach residential type classified apartment, house, urban and rural in by seasonal generation According to statistics of 2010MSW generation in Korea, On average, Namwon generated about 101.4 ton of trash and recycled almost 57.5 ton ofthis material per day, equivalent to a 56.7 percent recycling rate. It was recycled 0.73 kilograms out of individual wastegeneration of 1.29 kilograms per person per day. In 2011, On average, Namwon generated about 46.7 ton without recycledmaterial per day, and individual generation was 0.60 kilograms. It was virtually identical with statistics data in 2010. Inthe physico-chemical analysis results, it was composed of 84.1 percent of combustible and 15.9 percent of Non-combustible. On average, heat value was 2,529kcal per kilogram in condition of LHV and wet. The MSW sample wasincluded 32.0 percent of moisture, 21.9 percent of ash, 26.8 percent of carbon, 14.4 percent of oxygen, 3.7 percent ofhydrogen and 1.3 percent of others. Estimate of technical potential energy of MSW was 1,278 toe per year, equivalentto a 33.3 percent of total potential energy.
        49.
        2014.01 KCI 등재 서비스 종료(열람 제한)
        There have been a lot of efforts to increase recycling rate by more utilization of end of life vehicles (ELVs) in Korea.The target of recycling rate was set to 85% until 2014 and 95% after 2015 with including up to 10% of energy recovery,according to the law of “regulation about resource recycling of electrical and electronic products and automobiles”.Therefore, to achieve 95% of recycling rate by the year of 2015, the automobile and recycling industries should developan innovative technology to treat automobile shredder residues (ASRs) by efficient means of reduction or conversion toenergy, which were generated as final left-over after recovering all the valuables from ELVs. As one of the options toconvert to energy forms, the gasification of them was proposed. In this study the gasification experiment was performedusing ASRs at fixed-bed reactor with a capacity of 1kg/hr, at different temperatures of 800, 1,000 and 1,200oC, and atequivalence air ratios ranging from 0.1 to 0.5. The syngas (H2+CO) yield from ASR gasification experiment was obtainedup to 86% in maximum and about 40% in minimum in the experimental conditions given. There was a trend that theamount of syngas increased with elevated temperatures and the calorific value also showed similar trend with syngasproduction.
        50.
        2013.04 KCI 등재 서비스 종료(열람 제한)
        We investigated the effect of temperature and pressure in breakthrough performance of various sorbents for dechlorination and desulfurization. Based on the results obtained during the desulfurization (Fe2O3, Fe3O4, ZnO) and the dechlorination (Na2CO3, NaHCO3, trona) screening tests, ZnO and trona were selected as preferred optimum sorbents. H2S breakthrough time corresponds to an effective capacity of approximately 11 g H2S/100 g of sorbent. Also, HCl breakthrough time corresponds to an effective capacity of approximately 5 g HCl/100 g of sorbent. ZnO and trona at high temperature of around 550oC display high sorption performance and removal efficiency for synthsis gas from waste gasification. Although there is an issue of CO2 recovery in hot gas cleanup technology for desulfurization, we have obtained an interesting new alternative hot gas cleanup system with heat budget merit.
        51.
        2013.03 KCI 등재 서비스 종료(열람 제한)
        Gasification, one of the thermo-chemical conversion technologies, has been known and researched for the conversion of low graded solid feedstock to gaseous form of fuel. Gasification for obtaining high-valued combustible gas such as hydrogen and carbon monoxide has been focused again due to high oil price with needs of alternative energy. And the gaseous product, known as synthesis gas (syngas) can be effectively utilized in a variety of ways ranging from electricity production to chemical industry. Gasification and melting processes are also operated at high temperatures with the destruction of hazardous components and production of gases, mainly CO and H2, which can be utilized as fuel gas or raw chemicals after cleaning. In this study, sawdust was experimented on in a lab-scale gasification process in order to characterize the gaseous products. At isothermal conditions at a fixed temperatures (800, 1000, 1200oC), the concentrations of CO, H2 and CH4 increased but CO2 and N2 decreased with lower equivalent ratio (ER). C2H6 concentration was varying and not depending upon ER. Carbon conversion efficiency, gas and tar yields increased with increasing ERs. Tar yield was related to carbon conversion efficiency and gas yield.
        52.
        2012.09 KCI 등재 서비스 종료(열람 제한)
        In this study, fixed bed type CO2 gasification reactor was tested to enhance the production of synthetic gas (CO + H2) from low grade carbon source such as sewage sludge, wood chip, municipal waste, and low calofic valued coal. Various parameter effects on the 0.1 ton/day fixed bed gasifier operation were investigated. The parameters are reaction temperature, CO2/Air ratio, and total flow rate. Temperature was measured at the inlet and outlet of the reactor as well as at 18 positions along the reactor height and radius. The CO2 inlet concentration was tested between 0% and 30%. Total flow rate was varied from 40 L/min to 80 L/min at 20% CO2 inlet and 8 kg activated carbon packing. In the fixed bed CO2 gasification, CO2 took more parts in the gasification than combustion. But CO2 concentration higher than 40% made the two reactions unstable and the one between 20% and 40% did not give so much influence on the reaction time. The reaction time was shortened according to the total flow rate increase, and changed its slope gently above 50 L/min, illustarting CO2 gasification reaction is superior to combustion reaction in the low total flow rate condition.
        53.
        2012.09 KCI 등재 서비스 종료(열람 제한)
        In this study, C-CO2 reaction was investigated to achieve a simultaneous effect reducing green house gas and enhancing synthetic gas production. Carbon dioxide and oxygen were used as gasification agents in various concentrations. The Boudouard reaction in which CO2 reacts with carbon was expected for the enhancement of CO production. The reaction CO2 + C 2 CO was confirmed through thermo-gravimetric analysis (TGA) experiment. The weight of activated carbon used as a carbon source did not changed above 750oC in nitrogen condition, while sharply decreased in CO2 condition, illustrating the presence of Boudouard reaction. The weight of activated carbon and concentrations of H, H2, CH2, CH4, H2O, CO, O2, CO2 evolved from gasification reaction were continuously analysed in different gasification agent varying CO2 and O2 ratio. Weight loss rate increased according to the increase of oxygen ratio. The window on which CO peak evolved shifted to higher temperature according to CO2 concentration in gasification agent. It is proposed that varying CO2/O2 mole ratio can control the reaction ratio of combustion and gasification and shift concentration peak temperature.
        58.
        2010.09 KCI 등재 서비스 종료(열람 제한)
        석탄가스화는 청정석탄이용기술의 한 분야로 최근 국제 유가의 급격한 변동과 더불어 매우 각광을 받고 있는 기술이다. 본 연구에서는 중국 내몽고 지역의 저급석탄을 출발물질로 가스화를 위한 광학적 특성, X선 분광특성, X선 회절특성, 광물학적 특성, 건조특성 등을 분석하였다. 분석결과 석탄의 등급은 slagging성과 fouling성이 매우 낮으며 착화온도가 250℃ 정도인 brown coal인 것으로 조사되었고, 석영, 능철석, 점토광물 등이 주요 불순물로 혼재하는 것을 알 수 있었다. 또한 초기 수분이 28%로 매우 높기 때문에 이를 쉽게 건조하기 위한 방법으로 열풍건조와 마이크로웨이브 건조기술을 적용하여 비교한 결과, 마이크로웨이브를 이용한 건조가 좀 더 효과적인 것을 알 수 있었다.
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