• Title, Summary, Keyword: $CO_2$ Gasification

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Characteristics of Various Ranks of Coal Gasification with $CO_2$ by Gas Analysis (가스분석을 이용한 석탄 종류별 $CO_2$ 가스화 반응특성 연구)

  • Kim, Yong-Tack;Seo, Dong-Kyun;Hwang, Jung-Ho
    • Journal of the Korean Society of Combustion
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    • v.15 no.2
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    • pp.41-49
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    • 2010
  • Various coals from many countries around the world have been used for pulverized coal boiler in power plants in Korea. In this study, the gasification reactivities of various coal chars with $CO_2$ were investigated. Carbon conversion was measured using a real time gas analyzer with NDIR CO/$CO_2$ sensor. In a lab scale furnace, each coal sample was devolatilized at $950^{\circ}C$ in nitrogen atmosphere and became coal char and then further heated up to reach to a desired temperature. Each char was then gasified with $CO_2$ under isothermal conditions. The reactivities of coal chars were investigated at different temperatures. The shrinking core model (SCM) and volume reaction model(VRM) were used to interpret the experiment data. It was found that the SCM and VRM could describe well the experimental results within the carbon conversion of 0-0.98. The gasification rates for various coals were very different. The gasification rate for any coal increased as the volatile matter content increased.

Characteristics of $H_2$/CO ratio control of syngas by waste gasification (폐기물 가스화 합성가스의 $H_2$/CO 생산비 제어 특성)

  • Gu, Jae-Hoi;Kim, Su-Hyun;Kim, Mun-Hyun;Choi, Jong-Hyea;Heo, Su-Jung;Yoon, Ki-Soo;Kim, Soung-Hyoun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.475-478
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    • 2008
  • The 3 ton/day-scale pilot plant consists of waste press, feed channel, fixed bed type gasification & melting furnace, quench scrubber, syngas refinery facility and flare stack. $H_2$/CO ratio of gasification syngas using the solid waste and sludge in the 3 ton/day gasifier showed about 1. Gasification melting furnace was operated $1,300{\sim}1,600^{\circ}C$. $H_2$/CO ration control system was obtained $H_2$/CO ratio 2 and 3.

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Synthesis of Methane-rich Gases(Alternative Energy) by Thermochemical Gasification from Waste Municipal and Lignocellulosic Materials (목질 폐재와 가정용 쓰레기의 열-화학적 분해에 의한 고수율 메탄가스(대체연료)의 합성)

  • Lee, Byung-Guen;Lee, Sun-Haing
    • Journal of the Korean Wood Science and Technology
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    • v.17 no.2
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    • pp.13-19
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    • 1989
  • Two different quartz types of gasification reactor were used for pyrolysis and gasification of sawdust, ricestraw, ricehusk and municipal wastes which contain only cellulosics., operating at 1 atmospheric and vacuum pressure respectively. Also a stainless steel autoclave gasification reactor was used which is possible to use up to 100 atmospheric pressures and $800^{\circ}C$ of reaction temperature to complete pyrolysis and gasification reaction. The catalysts used in this reaction w- ere $K_2CO_3$, $Na_2CO_3$, Ni and Ni-$K_2CO_3$ as CO-Catalyst. The product gas mixtures were identified to be CO, $CO_2$, $C_3H_3$, $CH_4$ and $CH_3CHO$ etc. by Gas Chromatography and Mass Spectrometry. The pressurized gasification reaction shows significant increase in terms of methane composition and yield of product gases, comparing with those from unpressurized gasification reactions. The total volume of product gas mixtures amounts to 1600-1800ml per1gof waste of waste lignocellulosics or municipal waste, and the metane content of the gas mixtures reached to 40%, when $800^{\circ}C$ of reaction temperature and 100 atmospheric pressures with Ni-$K_2CO_3$ as CO-catalyst in the pressurized gasification reaction were used. This results show that the product gas mixtures containing 40% of methane call be used for alternative enegy source.

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Kinetic Studies of CO2 Gasification by Non-isothermal Method on Fly Ash Char (비등온법에 의한 비산재 촤의 CO2 가스화 특성)

  • Kang, Suk-Hwan;Ryu, Jae-Hong;Lee, Jin-Wook;Yun, Yongseung;Kim, Gyoo Tae;Kim, Yongjeon
    • Korean Chemical Engineering Research
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    • v.51 no.4
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    • pp.493-499
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    • 2013
  • For the purpose of utilizing fly ash from gasification of low rank coal, we performed the series of experiments such as pyrolysis and char-$CO_2$ gasification on fly ash by using the thermogravimetric analyzer (TGA) at non-isothermal heating conditions (10, 20 and $30^{\circ}C/min$). Pyrolysis rate has been analyzed by Kissinger method as a first order, the reliability of the model was lower because of the low content of volatile matter contained in the fly ash. The experimental results for the fly ash char-$CO_2$ gasification were analyzed by the shrinking core model, homogeneous model and random pore model and then were compared with them for the coal char-$CO_2$ gasification. The fly ash char (LG coal) with low-carbon has been successfully simulated by the homogeneous model as an activation energy of 200.8 kJ/mol. In particular, the fly ash char of KPU coal with high-carbon has been successfully described by the random pore model with the activation energy of 198.3 kJ/mol and was similar to the behavior for the $CO_2$ gasification of the coal char. As a result, the activation energy for the $CO_2$ gasification of two fly ash chars don't show a large difference, but we can confirm that the models for their $CO_2$ gasification depend on the amount of fixed carbon.

Premixed Combustion Characteristics of Coal Gasification Fuel in Constant Volume Combustion Chamber (석탄가스화 연료의 정적 예혼합 연소특성)

  • Kim Tae-Kwon;Jang Jun-Young
    • Journal of Environmental Science International
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    • v.15 no.6
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    • pp.601-606
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    • 2006
  • The coal gasification fuel is important to replace petroleum fuel. Also they have many benefits for reducing the air pollution. Measurements on the combustion characteristics of synthetic gas from coal gasification have been conducted as compared with LPG in constant volume combustion chamber. The fuel is low caloric synthetic gas containing carbon monoxide 30%, hydrogen 20%, carbon dioxide 5%, and nitrogen 45%. To elucidate the combustion characteristics of the coal gasification fuel, the combustion pressures, combustion durations, and pollutants(NOx, $CO_2$, CO) are measured with equivalence ratios($\phi$), and initial pressures of fuel-air mixture in constant volume chamber. In the case of the coal gasification fuel, maximum combustion pressure and NOx concentration are lower rather than LPG fuel. However CO and $CO_2$ emission concentration are similar to that of LPG fuel.

Experimental Study on CO2 Reaction Mechanism in Oxy Gasification Reaction Field (순산소 가스화 반응장에서 CO2 전환 메커니즘 연구)

  • Roh, Seon Ah;Yun, Jin Han;Keel, Sang In;Lee, Jung Kyu;Min, Tai Jin
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.4
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    • pp.285-290
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    • 2015
  • Oxy gasification was performed for the production of high quality syngas from the waste. $CO_2$ was used as reactant with $O_2$ for $CO_2$ gasification and greenhouse gas reduction. Therefore, gasification was performed at high temperature of $1000-1400^{\circ}C$. RPF was gasified in the thermobalance and 0.5 ton/day pilot plant gasifier. Weight variation with temperature and CO production by Boudouard reaction were studied for $CO_2$ gasification of RPF in thermobalance reactor. Syngas of high $H_2$ concentration was produced from oxy gasification in 0.5 ton/day pilot system, which showed appropriate $H_2$/CO ratio for the production of transport fuel and chemical products.

Comparative Studies on K2CO3-based Catalytic Gasification of Samhwa Raw Coal and Its Ash-free Coal (삼화 원탄과 무회분탄의 촉매(K2CO3) 가스화 반응성 비교 연구)

  • Kong, Yongjin;Lim, Junghwan;Rhim, Youngjoon;Chun, Donghyuk;Lee, Sihyun;Yoo, Jiho;Rhee, Young-Woo
    • Clean Technology
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    • v.20 no.3
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    • pp.218-225
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    • 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.

The characteristics of gasification for combustible waste

  • Na, Jae-Ik;Park, So-Jin;Kim, Yong-Koo;Lee, Jae-Goo;Kim, Jae-Ho
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • pp.227-234
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    • 2002
  • With the increasing environmental consideration and stricter regulations, gasification of waste is considered to be more attractive technology than conventional incineration for energy recovery as well as material recycling. The experiment for combustible waste mixed with plastic and cellulosic materials was performed in the fixed bed gasifier to investigate the gasification behavior with the operating conditions. Waste pelletized with a diameter of 2~3cm and 5cm of length was gasified at the temperature range of 1100~145$0^{\circ}C$. It was shown that the composition of H$_2$ was in the range of 30~40% and CO 15~30% depending upon oxygen/waste ratio. Casification of waste due to thermoplastic property from mixed plastic melting and thermal cracking shows a prominent difference from that of coal or coke. It was desirable to maintain the top temperature up to foot to ensure the mass transfer and uniform reaction through the packed bed. As the bed height was increased, the formation of H$_2$ and CO was increased whilst $CO_2$ decreased by the char-$CO_2$ reaction and plastic cracking. From the experimental results, the cold gas efficiency was around 61% and heating values of product gases were in the range of 2800~3200㎉/Nm3.

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A study on the direct catalytic steam gasification of coal for the bench-scale system

  • Kang, Tae-Jin;Park, HyeJung;Namkung, Hueon;Xu, Li-Hua;Park, Jung-Hyun;Heo, Iljeong;Chang, Tae-Sun;Kim, Beom Sik;Kim, Hyung-Taek
    • Korean Journal of Chemical Engineering
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    • v.34 no.10
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    • pp.2597-2609
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    • 2017
  • Various techniques have been developed to increase the efficiency of coal gasification. The use of a catalyst in the catalytic-steam gasification process lowers the activation energy required for the coal gasification reaction. Catalytic-steam gasification uses steam rather than oxygen as the oxidant and can lead to an increased $H_2/CO$ ratio. The purpose of this study was to evaluate the composition of syngas produced under various reaction conditions and the effects of these conditions on the catalyst performance in the gasification reaction. Simultaneous evaluation of the kinetic parameters was undertaken through a lab-scale experiment using Indonesian low rank coals and a bench-scale catalytic-steam gasifier design. The composition of the syngas and the reaction characteristics obtained in the lab- and bench-scale experiments employing the catalytic gasification reactor were compared. The optimal conditions for syngas production were empirically derived using lab-scale catalytic-steam gasification. Scale-up of a bench-scale catalytic-steam gasifier was based on the lab-scale results based on the similarities between the two systems. The results indicated that when the catalytic-steam gasification reaction was optimized by applying the $K_2CO_3$ catalyst to low rank coal, a higher hydrogen yield could be produced compared to the conventional gasification process, even at low temperature.

Characterization of CO2 Gasification of 17 Coals With Regard to Coal Rank (다양한 등급의 17종 석탄의 CO2 가스화 반응특성 연구)

  • Kim, Soohyun;Yoo, Jiho;Chun, Donghyuk;Lee, Sihyun;Rhee, Young Woo
    • Clean Technology
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    • v.19 no.3
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    • pp.333-341
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    • 2013
  • This paper presents results on $CO_2$ gasification of 17 raw coals containing a wide range of volatile matter (21-57 wt%). The gasification is performed using a TGA under $CO_2$ and also under $N_2$ atmosphere. An amount of weight loss with increasing temperature is proportional to that of volatile matter in a coal under $N_2$ atmosphere. Reactivity of $CO_2$ gasification also increases with a content of volatile matter. However, the correlation is a little scattered. Oxygenated functional groups in a coal are generally reactive and therefore, an increase in O/C ratio leads to enhanced reactivity. However, $CO_2$ reactivity is affected by neither H/C ratio nor a content of ashes that possibly activate the gasification reaction. These findings are also applicable to steam coal gasification and the reactivity series are confirmed in the test at a fixed bed reactor.