Effect of Exhaust Gas Cooling on PM in a Flue Gas Emitted from Spray Combustion of Sulfur-contained Fuel

( Y. Wu ),( K. Yamamoto ),( H. Wachi ),( T. Furuhata ),( M. Arai ) 한국액체미립화학회 2010 한국액체미립화학회 학술강연회 논문집 Vol.2010 No.-

Heat recovery from flue gas is very effective to economize fossil fuel, and results in the reduction of CO2 emission. However, the temperature of flue gas decreased with increasing the amount of recovery heat. It is thought that the decrease of temperature causes formation of secondary condensed particles in a flue gas. Furthermore, there is a possibility that sulfur in fuel promotes the formation of those particles when sulfur-contained fuel such as heavy fuel oil is burned. In this study, sulfur-contained kerosene (thiophene (C4H4S) added kerosene; mass fraction of sulfur was 1000ppm) was burned using a spray combustion furnace with long stack, and diameter distributions and compositions of particles in a flue gas were measured in order to understand the formation of secondary condensed particle. A water-cooled heat exchanger was used to cool down the flue gas before stack for the simulation of latent heat recovery. Flue gas was sampled from the stack with a thermal dilution sampling to analyze the characteristics of particles. When the flue gas was gradually and slightly cooled down in the stack, it was found that there was a peak between 10nm and 100nm in the diameter distribution. However, the peak disappeared with the thermal dilution sampling at 150°C or 300°C. It seemed that the disappeared particles were condensed ones such as sulfuric acid mist. When the flue gas was quickly cooled down with the heat exchanger, a similar peak was found with the dilution sampling at room temperature, but the peak did not disappeared and shifted to smaller diameters with the thermal dilution sampling at 150°C or 300°C. This result suggested that condense particles which were hard to evaporate or nano-size solid particles were formed in the process of heat recovery.

The effect of flue gas for cultivation of haematococcus pluvialis in outdoor condition

박명우,심상준,장원석 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

Flue gas from industries contains CO₂, NOx, and others which influence growth of microalga. So using flue gas from industries for cultivation microalga, the effect of flue gas was considered. In this study, using Haematococcus pluvialis which has green vegetative stage and red cyst stage. H. pluvialis was cultured in outdoor condition using 25L closed type photo-bioreactor which was maintained at 22~27°C of temperature, 50~400 mol photon/m²s of light intensity. And using flue gas from KDHC which averagely contains 5% CO₂, 11% O₂, 24ppm NOx and 46ppm CO. At each stages, there are some differences of flue gas concentration. The optimum condition of H. pluvialis is using mixed gas which consisted of 50% flue gas and 50% air for two weeks at first green vegetative stage for adaptation to flue gas. After that, red cyst stage, flue gas concentration was increased up to 100%.

열처리된 배연탈황석고를 혼입한 시멘트 모르타르의 물성 연구

정철우 ( Chung Chul-woo ),이용무 ( Lee Yong-mu ),김지현 ( Kim Ji-hyun ),김영수 ( Kim Young-su ) 한국건축시공학회 2016 한국건축시공학회지 Vol.16 No.6

배연탈황석고는 화력발전소에서 연료가 연소되면서 발생된 황산화물을 흡수, 제거하는 공정에서 발생되는 산업 부산물로서 최근 석탄 화력발전소의 배출가스에 관련된 환경규제가 대폭 강화됨에 따라 생산량이 점차 증가하고 있다. 배연탈황석고는 자연에서 얻어지는 형태의 천연석고와 거의 유사한 화학적 특성을 지니기 때문에, 이를 재활용하게 되면, 주로 수입에 의존하는 천연석고의 훌륭한 대체재로서 활용할 수 있다. 본 연구에서는 국내의 보령 화력발전소에서 생산된 배연탈황석고의 화학적 특성을 분석하고, 이를 이용하여 만든 시멘트 페이스트의 물성분석을 통하여, 배연탈황석고의 활용가능성을 평가하고자 하였다. 본 연구의 결과에 따르면, 배연탈황석고는 상당히 높은 순도를 가지며, 천연석고와 물성이 매우 유사한 것으로 나타났다. 또한 이를 적절하게 열처리하게 되면, 압축강도 및 건조수축에서의 개선효과를 얻을 수 있는 것으로 나타났다. Flue gas desulfurization gypsum is produced from emission process of fossil fuel power plant to remove sulfur dioxide (SO₂) from exhaust gas. Production of flue gas desulfurization gypsum in Republic of Korea has been increasing due to the enforced regulations by government agency. Since flue gas desulfurization gypsum has characteristic that is similar to that of natural gypsum, there is a strong possibility for flue gas desulfurization gypsum to replace the role of natural gypsum. However, consumption of such material is still limited, only used for agricultural purposes or to make gypsum boards, it is necessary to expand the use of this material more aggressively. In this research, the chemical and mineralogical properties of flue gas desulfurization gypsum were investigated, and flue gas desulfurization gypsum with heat treatment was used to make cement paste. According to the results, it was found that flue gas desulfurization gypsum used in this experiment was a very high purity gypsum, and shown to have similar property to that of natural gypsum. Heat treating flue gas desulfurization gypsum above 100℃ was shown to bring beneficial effect on both compressive strength and drying shrinkage.

폴리설폰 중공사막을 이용한 연소 배기가스 중 이산화탄소 분리에 관한 연구

김성천(Seong Cheon Kim),전정현(Jeong Hyeon Chun),전영남(Young Nam Chun) 大韓環境工學會 2014 대한환경공학회지 Vol.36 No.2

본 연구에서는 폴리설폰 중공사막을 이용하여 화석연료 연소에서 배출되는 온실가스 중 CO₂의 회수에 관한 연구를 실시하였다. 고농도의 CO₂를 회수하기 위한 막분리 공정에 대한 선행연구이다. 혼합가스 분리거동 관찰을 위하여 이산화탄소가 10% 함유된 배기가스를 사용하였다. 압력, 온도, 주입가스 조성, 다단 막 변화를 주어 스테이지 컷에 따른 분리 성능을 조사하였다. 압력과 온도가 증가 할수록 투과측에 CO₂ 농도와 회수율이 증가하였다. 주입 가스 조성 변화 시 CO₂의 함량이 높을 경우 회수율 및 분리 효율이 높아졌다. 3단 분리막 시스템을 이용시 CO₂ 농도 95% 이상, 회수율 90% 이상 보였으며 1단분리막 보다 분리율이 향상되었다. In this research, polysulfone hollow fiber membrane was used to recover CO₂ which is one of greenhouse gases from flue gas stream being emitted after the combustion of fossil fuels. The prerequisite requirement is to design the membrane process producing high-purity CO₂ from flue gas. For separation of CO₂, a membrane module and flue gas containing 10% carbon dioxide was used. The effects of operating conditions such as pressure, temperature, feed gas composition and multi-stage membrane on separation performance were examined at various stage cuts. Higher operating pressure and temperature increased carbon dioxide concentration and recovery ratio in permeate. Recovery ratio and separation efficiency increased if a higher content of CO₂ injection gas composition. Three-stage membrane system was producing a 95% CO₂ with 90% recovery from flue gas. The separation efficiency of three-stage membrane system was higher than one-stage system.

CH₄ recovery and CO₂ sequestration using flue gas in natural gas hydrates as revealed by a micro-differential scanning calorimeter

Lee, Y.,Kim, Y.,Lee, J.,Lee, H.,Seo, Y. Applied Science Publishers 2015 APPLIED ENERGY Vol.150 No.-

The CH<SUB>4</SUB>-flue gas replacement in naturally occurring gas hydrates has attracted significant attention due to its potential as a method of exploitation of clean energy and sequestration of CO<SUB>2</SUB>. In the replacement process, the thermodynamic and structural properties of the mixed gas hydrates are critical factors to predict the heat flow in the hydrate-bearing sediments and the heat required for hydrate dissociation, and to evaluate the CO<SUB>2</SUB> storage capacity of hydrate reservoirs. In this study, the <SUP>13</SUP>C NMR and gas composition analyses confirmed that the preferential enclathration of N<SUB>2</SUB> molecules in small 5<SUP>12</SUP> cages of structure I hydrates improved the extent of the CH<SUB>4</SUB> recovery. A high pressure micro-differential scanning calorimeter (HP μ-DSC) provided reliable hydrate stability conditions and heat of dissociation values in the porous silica gels after the replacement, which confirmed that CH<SUB>4</SUB> in the hydrates was successfully replaced with flue gas. A heat flow change associated with the dissociation and formation of hydrates was not noticeable during the CH<SUB>4</SUB>-flue gas replacement. Therefore, this study reveals that CH<SUB>4</SUB>-flue gas swapping occurs without structural transitions and significant hydrate dissociations.

다공성 매질에서 가스하이드레이트 치환생산기법 이용 시 배가스 주입유속 효과에 대한 실험적 연구

이동건,이주용,이재형 한국자원공학회 2009 한국자원공학회지 Vol.46 No.1

Previous studies of swapping method on hydrate have been focused on bulk hydrate. But, for realistic production of gas hydrate, it is necessary to investigate fluid flow behaviour in hydrate reservoir and recovery efficiency according to various production techniques. In this study, gas hydrate production has been conducted using swapping method to investigate the effect of flue gas injection rate in unconsolidated artificial sand sample. The recovery of methane gas decreased with increasing the injection rate of flue gas. It showed that rapid injecting velocity of flue gas was able to play an inhibitor for hydrate production. And it's possible that additional methane gas recovery each time the number of soaking is increased. The recovery characteristics with flue gas and soaking process can be applied for feasibility study for gas hydrate development using swapping method. 본 연구에서는 배가스 치환생산 실험시스템을 구축하여 하이드레이트 저류층 공극시스템에서의 치환생산거동을 파악하고 배가스 주입유속이 메탄가스 회수에 미치는 영향을 분석하였다. 배가스 주입실험 결과, 주입유속이 빠를수록 메탄가스의 회수율은 감소하였다. 이는 하이드레이트와 배가스 간에 치환을 일으키는데 필요한 최소반응시간이 줄어들어 일종의 반응 억제제 역할을 하였기 때문이라고 사료된다. 또한 soaking을 할 때마다 메탄가스의 추가적인 회수가 가능하였다. 주입유속이 느릴수록 치환효율이 증가하고 soaking을 할 때 마다 메탄가스가 추가로 생산되는 점을 미루어볼 때, 두 변수는 추가회수기작에 중요한 역할을 한다고 사료된다. 특히 주입유속이 느려질수록 더욱 큰 생산량 증가를 보이는 것은 접촉시간이 증대되어 치환생산량의 향상을 도모 할 수 있음을 의미한다. 하지만 실제 현장 적용 시 막연히 낮은 유속으로만 배가스를 주입하거나 긴 soaking시간에 의존하여 생산정을 운영한다면 생산지연 및 운영비용 증가의 문제를 야기할 수 있다. 이러한 연구결과는 배가스 치환기법을 이용한 가스하이드레이트 저류층 개발 시, 개발타당성 분석 및 생산계획수립을 위한 기초자료로 활용 가능할 것으로 판단된다.

Characterization of Enriched CO₂ Gas from Oxy-fuel Combustion of Waste Sludge and Wood-chip during Flue-gas Recirculation in Circulating Fluidized Bed

( Jin-ho Sung ),( Ha-na Jang ),( Seung-ki Back ),( Bup-mook Jeong ),( Yong-chil Seo ),( Jeong-hun Kim ),( Yun-tak Cho ),( Jong-il Kim ),( Hyun-je Sung ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-

Fossil fuel combustion generates large amount of green house gas, which was mainly considered as a major contributing emission source of global warming. In order to reduce green house gas, renewable energy has been emerged as an alternative energy. Waste and biomass are considered major resource as one of renewable energy, but it has been not utilized sufficiently. In this paper, waste sludge and wood chip fuel were utilized as main fuels in order to develop technology of waste to energy using oxy-fuel combustion in circulating fluidized bed. In oxy-fuel combustion, oxygen injection rate and superficial velocity were determined as 23% and 2.27m/s for fast fluidization, respectively. Fuel feeding rate was calculated as 13kg/hr. For producing high purity carbon dioxide, flue gas recirculation system was operated with oxy-fuel combustion. During flue-gas recirculation, temperature gradient was more homogeneous, and the stable combustion was maintained. Finally, the carbon dioxide in flue-gas was enriched above 90% to apply carbon capture and storage technology.

O₂/CO₂ 혼합조건에 따른 LNG 연소특성해석

김혜숙(Hey Suk Kim),신미수(Mi Soo Shin),장동순(Dong Soon Jang),이대근(Dae Geun Lee) 大韓環境工學會 2007 대한환경공학회지 Vol.29 No.6

본 연구의 목적은 기존의 산업용 보일러에서 이산화탄소 배출저감을 위하여 연소가스 재순환에 의한 고온 순산소 연소기술을 개발하는데 있다. 이를 위해 실험실 규모의 LNG 연소기에서 연소 화염특성을 평가하기 위한 조직적인 수치해석 연구가 일차적으로 수행되었다. 특히 본 연구에서 고려한 중요한 변수는 산소부화환경에서 계산된 연소가스의 재순환 정도이다. 배기가스 재순환이 없는 100% 순산소 연소환경에서 화염은 고온의 길고 가는 층류형상의 화염을 보였다. 이는 산화제 중에서 질소성분이 감소함으로써 약화된 난류혼합효과와 N2 가스에 의한 현열손실의 감소에 기인하는 것으로 판단하였으며 문헌에 발표된 실험과 일치된 결과를 보였다. O₂/CO₂ 혼합가스에서 CO₂ 가스의 재순환율이 증가될수록 산화제의 유량 증가에 따른 강화된 난류혼합으로 인해 최고 화염온도가 버너 근처로 이동한 반면 전반적인 연소가스 온도는 N2에 비해 CO₂의 높은 비열로 인해 낮아지는 현상을 보였다. 결국 80% 이상 CO₂ 가스를 재순환한 경우 연소가스의 온도가 급격하게 떨어지는 화염소멸 현상을 보여주었다. 그러나 30% O₂/70% CO₂의 혼합 연소조건에서는 기존의 공기연소와 유사한 가스온도를 나타내었다. 이외에도 공기연소와 동일한 유량조건에서 난류강도와 열수지 측면에서 화염특성 변화를 평가하기 위한 면밀한 연구가 수행되었다. The ultimate objective of this study is to develop a reliable oxygen-enriched combustion techniques especially for the case of the flue gas recycling in order to reduce the CO₂ emissions from practical industrial boilers. To this end a systematic numerical investigation has been performed, as a first step, for the resolution of the combusting flame characteristics of lab-scale LNG combustor. One of the important parameters considered in this study is the level of flue gas recycling calculated in oxygen enriched environment. As a summary of flame characteristics, for the condition of 100% pure O₂ as oxidizer without any flue gas recycling, the flame appears as long and thin laminar-like shape with relatively high flame temperature. The feature of high peak of flame temperature is explained by the absence of dilution and heat loss effects due to the presence of N2 inert gas. The same reasoning is also applicable to the laminarized thin flame one, which is attributed to the decrease of the turbulent mixing. These results are physically acceptable and consistent and further generally in good agreement with experimental results appeared in open literature. As the level of CO₂ recycling increases in the mixture of O₂/CO₂, the peak flame temperature moves near the burner region due to the enhanced turbulent mixing by the increased amount of flow rate of oxidizer stream. However, as might be expected, the flue gas temperature decreases due to presence of CO₂ gas together with the inherent feature of large specific heat of this gas. If the recycling ratio more than 80%, gas temperatures drop so significantly that a steady combustion flame can no longer sustain within the furnace. However, combustion in the condition of 30% O₂/70% CO₂ can produce similar gas temperature profiles to those of conventional combustion in air oxidizer. An indepth analyses have been made for the change of flame characteristics in the aspect of turbulent intensity and heat balance.

국내 가정용 목재 펠릿 보일러 성능 및 배기 특성 분석

강새별(Sae Byul Kang),김종진(Jong Jin Kim),최규성(Kyu Sung Choi) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-

We conducted performance tests of 23.2 ㎾ (20,000 ㎉/h) class domestic wood pellet boilers. The objectives of this paper are 1) to introduce wood pellet and wood pellet boilers, 2) to show the range of thermal efficiency of domestic wood pellet boilers and 3) to let wood pellet boiler manufacturer know the state of technology level of the other wood pellet boiler manufacturer, such as thermal efficiency and flue gas concentration. We conducted 11 performance tests of wood pellet boiler. Average higher heating value of dry wood pellets used to boiler performance tests is 19.2 MJ/㎏ (4,580 ㎉/㎏) and average water content based on wet base is 8.3 %. The test results show that thermal efficiency of domestic wood pellet boiler is about 80.5 % based on lower heating value which is lower than that of domestic gas boiler of 90.7 %. Flue gas temperature is higher than that of domestic gas boilers. Average flue gas temperature of wood pellet boilers is 201 ℃. As temperature of flue gas goes up, the efficiency of wood pellet boiler decreases. We measured O2, CO and NOx concentration of boiler flue gas. The range of CO concentration is 50 ~ 2,000 ppm and NOx concentration is 60 ~ 120 ppm.

배가스 재순환 공정에서 산소 농도 및 유속에 따른 소결층 내 연소 반응

이영헌(Younghun Lee),최상민(Sangmin Choi),양원(Won Yang),조병국(Byungkook Cho) 한국연소학회 2011 KOSCOSYMPOSIUM논문집 Vol.- No.43

In the iron ore sintering process, operation conditions control the bed temperature and quality of sintered ore. The operation conditions are inlet gas velocity, composition and temperature and bed composition. Applying the flue gas recirculation in sintering process change the oxygen concentration and velocity of inlet gas. To make the evenly heat concentration in the bed, optimized the suction and injection location and quantity of flue gas. In this study, the influence of flue gas recirculation is analysed by previously developed unsteady 1-dimensional model of an iron ore sintering bed. To evaluate the cases, quantitative parameters are applied to the calculation results, and then evaluation results are used to offer the proper operational conditions.