• Clean Technology
• /
• v.20 no.3
• /
• pp.218-225
• /
• 2014

Catalytic gasification of raw coals at mild condition is not realized yet mainly due to deactivation of catalysts via their irreversible interaction with mineral matters in coal. In this work, the gasification behavior of ash-free coal (AFC) was compared with that of the parent raw coal. In order to modify the gasification conditions, the raw coal gasified with fixed variables (water supply, space velocity, temperature, catalysts) in a fixed bed reactor. When catalysts are added by physical mixing method with coal, $K_2CO_3$ was the most effective additives for steam gasification of coal. However, the activity of ash-free coal (AFC) was much less reactive than raw coal due to high temperature extraction in a 1-methylnaphthalene under 30bar at $370^{\circ}C$ for 1 h, almost removed oxygen functional groups, and increased carbonization. The addition of $K_2CO_3$ in AFC achieved higher conversion rate at low temperature ($700^{\circ}C$). At that time, the molar ratio of gases ($H_2/CO$ and $CO_2/CO$) was increased because of water-gas shift reaction (WGSR) by addition of catalysts. This shows that catalytic steam gasification of AFCs is achievable for economic improvement of gasification process at mild temperature.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1998.05a
• /
• pp.79-84
• /
• 1998

고압 분류층 가스화기는 탄소전환율을 높이기 위해 고온, 즉 Ash Slagging 조건보다 높은 온도에서 운전된다. 따라서 분류층 가스화기에서 생산되어 배출되는 Raw Syngas는 고온의 현열을 보유하고 있다. 고온의 반응과정으로 인하여 타르나 기타 중탄화수소가 생성되지 않으므로 발생열을 회수하기가 용이하며 가스정제 및 불순물 제거과정도 단순해진다. (중략)

• Plant Journal
• /
• v.17 no.1
• /
• pp.58-66
• /
• 2021

The government has recently come up with a policy to tighten regulations on air pollutant emissions due to public concerns over the emission of pollutants such as fine dust. The coal-fired power plant is speeding up the improvement of the performance of environmental facilities, and this paper deals with the cases of performance improvement by adding a catalyst to the 500 MW standard coal-fired power DeNox system, and examines the change in the performance factors according to the addition of catalysts and the efficiency of NOx removal. The DeNOx efficiency before and after improvement increased from 80% to 88%, and the conversion rate of SO2/SO3, ammonia slip which are performance factors satisfied the design assurance value, but exceeded the design assurance value for differential pressure. At the same time, the ammonia slip concentration and differential pressure items increased as the NOx removal efficiency increased, resulting in the need for management and improvement.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.130.2-130.2
• /
• 2010

2020년까지 대형 CCS (Carbon Capture and Storage) Demo Plant 시장 (100MW 이상) 이 형성될 전망이다. 발전 부문에서 대규모 CCS 실증 프로젝트는 총 44개이며 연소전(41%), 연소후(28%), 순산소(3%) 프로젝트가 계획되어 있다. 순산소 연소 기술은 실증진입단계, 연소후(USC) 기술은 상용화 추진단계, 연소전 (IGCC) 기술은 실증완료 이후 상용화 진입 단계이다. IGCC 발전의 석탄가스화 기술은 타 산업분야에 서 상용화 되어있어 기술신뢰성이 높다. IGCC 단위설비 기술 개발을 통한 성능개선 및 비용절감에 대한 잠재력을 가지고 있기 때문에 미래의 석탄발전기술로 고려되고 있다. IGCC 기술은 가장 상용화에 앞서있지만 아직까지 IGCC+CCS 대형 설비가 운전된 사례가 전 세계적으로 없으며 미국 EPRI 등에서 Feasibility Study 단계이다. 현재 국책과제로 수행중인 300MW급 태안 IGCC 플랜트를 대상으로 향후 CCS 설비를 적용했을 경우에 대해 기술 타당성 검증을 목적으로 IGCC+CCS 모델링을 수행하였다. 모델링은 스크러버 후단의 합성 가스를 대상으로 하였다. Water Gas Shift Reaction (WGSR) 공정 및 Selexol 공정을 구성하여 최종 단에서 수소 연료를 생산할 수 있도록 하였다. WGSR 공정은 Co/Mo 촉매반응기로 구성되었다. WGSR 모델링을 통하여 주입되는 스팀량 (1~2 mol-steam/mol-CO) 및 온도 변화 ($220-550^{\circ}C$)에 따른 CO가스의 전환율을 분석하여 경제적인 설계조건을 선정하였다. Selexol 공정은 $H_2S$ Absorber, $H_2S$ Stripper, $CO_2$ Absorber, $CO_2$ Flash Drum으로 구성된다. Selexol 공정의 $CO_2$와 $H_2S$ 선택도를 분석 하였으며 단위 설비별 설계 조건을 예측하였다. 모델링 결과 59kg/s의 합성가스($137^{\circ}C$, 41bar, 가스 조성은 $CO_2$ 1.2%, CO 57.2%, $H_2$ 23.2%, $H_2S$ 0.02%)가 WGSR Process를 통해 98% CO가 $CO_2$ 로 전환되었다. Selexol 공정을 통해 $H_2S$ 제거율은 99.9%, $CO_2$제거율은 96.4%이었고 14.9kg/s의 $H_2$(86.9%) 연료를 얻었다. 모델링 결과는 신뢰성 검증을 통해 IGCC+CCS 전체 플랜트의 성능예측과 Feasibility Study를 위한 자료로 활용될 예정이다.

• Korean Chemical Engineering Research
• /
• v.44 no.4
• /
• pp.356-362
• /
• 2006

The $SO_2$ reduction using CO and $H_2$ over Sn-Zr based catalysts was performed in this study. Sn-Zr based catalysts with Sn/Zr molar ratio (0/1, 1/4, 1/1, 2/1, 3/1, 1/0) were prepared by the precipitation and co-precipitation method. The effect of the temperature on the reaction characteristics of the $SO_2$ reduction with a reducing agent such as $H_2$ and CO was investigated under the conditions of space velocity of $10,000ml/g_{-cat.}h$, $([CO(or\;H_2)]/[SO_2])$ of 2.0. As a result, the activity of Sn-Zr based catalysts were higher than $SnO_2$ and $ZrO_2$. The reactivity for the $SO_2$ reduction with CO was higher than that with $H_2$, and sulfur yield in the $SO_2$ reduction by $H_2$ was higher than that by CO. The reactivity for the $SO_2$ reduction with $H_2$ was increased with the reaction temperature regardless of Sn-Zr based catalyst with a Sn/Zr molar ratio. $SnO_2-ZrO_2$ (Sn/Zr=1/4) had highest activity at $550^{\circ}C$, in the $SO_2$ reduction with $H_2$ and $SO_2$ conversion of 94.4％ and sulfur yield of 66.4％ were obtained at $550^{\circ}C$. On the other hand, in the $SO_2$ reduction by CO, the reactivity was decreased with the increase over $325^{\circ}C$. At the optimal temperature of $325^{\circ}C$, $SO_2$ conversion and sulfur yield were about 100％ and 99.5％, respectively, in the $SO_2$ reduction over $SnO_2-ZrO_2$ (Sn/Zr=3/1). Also, the $SO_2$ reduction using syngas with $CO/H_2$ ratio over $SnO_2-ZrO_2$ (Sn/Zr=2/1) was performed in order to investigate the application possibility of the simulated coal gas as the reductant in DSRP. As a result, the reactivity of the $SO_2$ reduction using syngas with $CO/H_2$ ratio was increased with increasing the CO content of syngas. Therefore, it could be known that DSRP using the simulated coal gas over Sn-Zr based catalyst is possible to be realized in IGCC system

• Applied Chemistry for Engineering
• /
• v.22 no.3
• /
• pp.312-318
• /
• 2011

We have investigated the kinetics and catalytic activity of $CO_2$-lignite gasification with various metal precursors as catalysts. $K_2CO_3$, $Mn(NO_3)_2$, and $Ce(NO_3)_3$ were used and impregnated on a coal using an evaporator. The gasification experiments were carried out with the low rank coal loaded with 5 wt% catalyst at the temperature range from $700{\sim}900^{\circ}C$ and atmospheric pressure with the $N_2-CO_2$ reactant gas mixture. The catalytic effect on the gasification rate of the low rank coal with $CO_2$ was determined by the thermogravimetric analyzer. It was observed that the low rank coal reached the complete carbon conversion regardless of the kinds of catalysts at $900^{\circ}C$ from the results of TGA. The catalytic activity was ranked as 5 wt% $K_2CO_3$ > 5 wt% $Mn(NO_3)_2$ > 5 wt% $Ce(NO_3)_3$ > Non-catalyst at $900^{\circ}C$. The gasification rate increased with increasing the temperature. The activation energy of the catalytic gasification with 5 wt% $K_2CO_3$ was 119.0 kJ/mol, which was the lowest among all catalysts.

• Clean Technology
• /
• v.21 no.1
• /
• pp.53-61
• /
• 2015

In this study, we have investigated the kinetics on the char-CO₂ catalytic gasification reaction. Thermogravimetric analysis (TGA) experiments were carried out for char-CO₂ catalytic gasification of an Indonesian Kideco sub-bituminous. Na₂CO₃ and K₂CO₃ were selected as catalysts which were physically mixed with coal. The char-CO₂ catalytic gasification reaction showed a rapid increase of carbon conversion rate at 850 ℃, 60 vol% CO₂, and 7 wt% Na₂CO₃. At the isothermal conditions ranging from 750 ℃ to 900 ℃, the carbon conversion rates increased as the temperature increased. Four kinetic models for gas-solid reaction including the shrinking core model (SCM), random pore model (RPM), volumetric reaction model (VRM), and modified volumetric reaction model (MVRM) were applied to the experimental data against the measured kinetic data. The gasification kinetics were suitably described by the MVRM for the Kideco sub-bituminous. The activation energies for each char mixed with Na₂CO₃ and K₂CO₃ were found 55-71 kJ/mol and 69-87 kJ/mol.

• Membrane Journal
• /
• v.5 no.3
• /
• pp.97-108
• /
• 1995

화학산업의 급속한 성장으로 인해 많은 혜택을 얻고 있지만 반대급부적으로 배출되는 오염물질로 인한 환경오염과 석유 및 석탄과 같은 한정된 화석연료 자원의 과다한 사용이 큰 문제가 되고 있다. 그에 따라 최근에는 효율적인 에너지 활용과 함께 오염물질의 배출을 최대로 억제할 수 있는 경제적이고 션택적인 화학공정을 필요로 하고 있다. 현재 세계적인 기술의 흐름은 대기오염의 억제와 소량 배출되는 오염물질의 제거를 위해 촉매 및 흡착제를 사용하여 다량의 오염물질 또는 기체를 처리할 수 있는 공정의 개발 및 변형에 많은 노력을 기울이고 있다. 그러나 보다 바람직하게는 높은 전환율과 선택적인 화학공정의 도입으로 에너지 효율을 증대시켜 에너지를 절약하고 부산물이 적은 보다 청결한 화학공정으로의 전화을 필요로 하고 있다. 이러한 목적을 위해 무리막의 분리능력과 촉매의 활성을 결합하여 촉매반응과 반응물 및 생성물의 분리기능을 동시에 수행할 수 있는 무기막 촉매기술이 최근들어 광범위하게 연구되고 있다. 또한 최근에는 무기막 및 무기막 촉매의 환경분야에의 이용이 크게 확산되어 가고 있는 추세이기 때문에 막 및 막 촉매 기술은 중요성이 매우 높은 분야이다. 따라서 본 고찰에서는 최근에 연구가 활발히 진행되고 있는 무기막 촉매기술의 특성과 연구 현황 및 방향에 관해 살펴보고 향후 연구방향의 기초자료로서 활용하고자 한다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.11a
• /
• pp.73.2-73.2
• /
• 2011

합성천연가스(SNG: Synthetic Natural Gas)를 얻기 위해, 석탄 가스화로부터 얻은 합성가스는 일반적으로 수소와 일산화탄소의 비가 3.0($H_2$/CO)이 되도록 수성가스전환(WGS)반응을 거친 후 메탄화반응기로 유입되며, 가능하면 낮은 온도에서 메탄 전환율이 높은 메탄화 반응의 특성상 강한 발열반응이 수반되므로 이를 낮추는 것이 중요하다. 또한, 최종생성물내의 메탄 농도를 높이기 위해 WGS 이후 탈황과 동시에 이산화탄소를 제거하기 위한 공정이 요구된다. 본 연구에서는 정제된 합성가스의 WGS와 이산화탄소 제거가 생략된 공정을 개발하기 위해, 상업용 촉매에 대하여 수소의 농도가 낮은 합성가스를 이용하여 스팀과 이산화탄소에 대한 메탄화반응 특성을 평가하였다. 또한, 이산화탄소의 존재여부에 따라 스팀으로 메탄화반응과 WGS가 동시에 일어날 수 있는 최적의 운전조건을 얻고자 하였다.

• Korean Chemical Engineering Research
• /
• v.50 no.3
• /
• pp.511-515
• /
• 2012

In this study, we used a commercial simulator to investigate the gasification characteristics of Roto coal in the partitioned fluidized-bed gasifier, which consists of 4 parts such as coal pyrolysis, char gasification, tar/oil gasification and char combustion. The heating medium was exchanged between the combustion part and the gasification part in order to supply the energy needed for pyrolysis and gasification. The correlation model from experimental data in relation to the reaction temperatures, the reaction gases and the coal feed rates was derived for the coal pyrolysis. The equilibrium model was used for the gasification and the combustion model for the char combustion. In order to compare the reaction behavior of the partitioned fluidized-bed gasifier, the single-bed gasifier was also simulated. The cold gas efficiency of both partitioned fluidized-bed gasifier and single-bed gasifier was almost the same. The $H_2$ and $CH_4$ contents of the syngas in the partitioned fluidized-bed gasifier slightly increased and the CO and $CO_2$ contents slightly decreased, compared with the singlebed gasifier. In order to verify the model, ten cases of the single-bed gasification experiment have been simulated. The contents of CO, $CO_2$, $CH_4$ in the syngas from the simulation corresponded with the experimental data while those of $H_2$ was slightly higher than experimental data, but the tendency of $H_2$ content in the syngas was similar to the experiments. In the coal conversion, the simulation results were higher than the experiments since equilibrium model was used for the gasification so that the residence time and contact time in the model is different from the experiments.