• Title/Summary/Keyword: Cold Gas Efficiency

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Coal Gasification using Catalyst in a Fluidized Bed Reactor (유동층 반응기에서 촉매를 이용한 석탄 가스화반응 특성)

  • 이운재;김상돈
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 1995.05a
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    • pp.129-132
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    • 1995
  • 상압의 유동층반응기 (0.1 m-i.d x 1.6 m-high) 에서 호주탄을 수증기와 공기를 사용하여 가스화 하였다. 또한 반응기에서 촉매효과를 고찰하기 위해 $K_2$SO$_4$+Ni(NO$_3$)$_2$ 촉매를 호주탄에 담지하여 가스화반응을 수행하였다. 생성가스조성, 생성가스량, 탄소전환율, cold gas efficiency 및 발열량 등에 대한 유동화속도 (2~5U$_{mf}$), 반응온도 (750~90$0^{\circ}C$), 공기/석탄 비 (1.6~3.2), 수증기/석탄 비 (0.63~l.26)의 영향을 조사하였다. 탄소전환율, 생성 가스량, 생성가스 발열량 및 cold gas efficiency 는 유동화속도와 반응온도의 증가에 따라 증가하였다. 공기/석탄 비가 증가함에 따라 탄소전환율과 생성가스량 및 cold gas efficiency 는 증가하지만 생성가스 발열량은 감소하였다. 수증기/석탄 비의 증가에 따라 발열량, cold gas efficiency 및 생성가스량은 증가하였으며, 탄소 전환율은 거의 일정하였다. 촉매 가스화반응에서 유동화속도, 반응온도, 공기/석탄 비 및 수증기/석탄 비의 증가에 따라 탄소 전환 율, 생성가스량, 생성가스 발열량 및 cold gas efficiency 는 크게 향상됨을 알 수 있었다.

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Comparative studies of gasification potential of agro-waste with wood and their characterization

  • Tripathi, Amarmani;Shukla, S.K.
    • Advances in Energy Research
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    • v.3 no.3
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    • pp.181-194
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    • 2015
  • In this work, an experimental study of the gasification on wood was carried out in downdraft type fixed bed Gasifier attached with 10 kW duel fuel diesel engine. The main objective of the study was to use wood as the biomass fuel for downdraft Gasifier and to evaluate the operating parameter of gasifier unit to predict its performance in terms of gas yield and cold gas efficiency. The influence of different biomass on fuel consumption rate, gas yield and cold gas efficiency was studied. Composition of producer gas was also detected for measuring the lower heating value of producer gas to select the feed stock so that optimum performance in the existing gasifier unit can be achieved. Under the experimental conditions, Lower heating value, of producer gas, cold gas efficiency and gas yields, using wood as a feed stock, are $4.85MJ/m^3$, 46.57% and $0.519m^3/kg$.

Design and Exergy Analysis for a Combined Cycle of Liquid/Solid $CO_2$ Production and Gas Turbine using LNG Cold/Hot Energy

  • Lee, Geun-Sik
    • International Journal of Air-Conditioning and Refrigeration
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    • v.15 no.1
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    • pp.34-45
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    • 2007
  • In order to reduce the compression power and to use the overall energy contained in LNG effectively, a combined cycle is devised and simulated. The combined cycle is composed of two cycles; one is an open cycle of liquid/solid carbon dioxide production cycle utilizing LNG cold energy in $CO_2$ condenser and the other is a closed cycle gas turbine which supplies power to the $CO_2$ cycle, utilizes LNG cold energy for lowering the compressor inlet temperature, and uses the heating value of LNG at the burner. The power consumed for the $CO_2$ cycle is investigated in terms of a solid $CO_2$ production ratio. The present study shows that much reduction in both $CO_2$ compression power (only 35% of the power used in conventional dry ice production cycle) and $CO_2$ condenser pressure could be achieved by utilizing LNG cold energy and that high cycle efficiency (55.3% at maximum power condition) in the gas turbine could be accomplished with the adoption of compressor inlet cooling and regenerator. Exergy analysis shows that irreversibility in the combined cycle increases linearly as a solid $CO_2$ production ratio increases and most of the irreversibility occurs in the condenser and the heat exchanger for compressor inlet cooling. Hence, incoming LNG cold energy to the above components should be used more effectively.

Gasification of Coal and Torrefied Biomass Mixture (석탄과 반탄화 바이오매스 혼합연료의 가스화)

  • OH, GUNUNG;JANG, JIN YOUNG;RA, HO WON;SEO, MYUNG WON;MUN, TAE YOUNG;LEE, JAE-GOO;YOON, SANG JUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.2
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    • pp.190-199
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    • 2017
  • Air-blown Gasification of coal and torrefied biomass mixture is conducted on fixed-bed gasifier. The various ratio (9:1, 8:2, 7:3) of coal and torrefied biomass mixture are used. The contents of $H_2$, CO in the syngas were increased with gasification temperature. Carbon conversion tend to increase with temperature and equivalence ratio (ER). However, cold gas efficiency showed maximum point in ER range of 0.26-0.36. The torrefied biomass showed highest cold gas efficiency of 67.5% at $934^{\circ}C$, ER 0.36. Gasification of 8:2 mixture showed the highest carbon conversion and cold gas efficiency and synergy effect.

Pressurized Drop Tube Furnace Tests of Global Gasification Characteristics of Coal (PDTF를 이용한 석탄가스화 특성 실험)

  • 신용승;최상민;안달홍
    • Journal of Energy Engineering
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    • v.8 no.4
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    • pp.560-566
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    • 1999
  • PDTF (Pressurized drop tube furnace) experiments using variations of temperature, oxygen/coal ratio, steam/coal and pressure with Roto coal (Sub A) were performed in order to investigate the effects of these experimental parameters on global gasification characteristics at elevated pressure. The results shows that the gasification at elevated pressure is more profitable than that at atmospheric pressure considering the carbon conversion and cold gas efficiency. The oxygen/coal ratio at which maximum cold gas efficiency was appeared ranged from 0.5 to 0.7 g/g. only when the temperature is sufficiently high enough, the raise of steam/coal ratio brings improvement of cold gas efficiency. As the pressure increased, the volume of carbon conversion by heterogeneous reaction increased but the volume of carbon conversion by pyrolysis decreased relatively.

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Pressurized drop tube furnace tests of global gasification characteristics of coal (PDTF를 이용한 석탄가스화 특성 실험)

  • 신용승;최상민;안달홍
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 1999.05a
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    • pp.23-31
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    • 1999
  • PDTF(Pressurized drop tube furnace) experiments using varied temperature, oxygen/coal ratio, steam/coal ratio and pressure with Roto coal(Sub A) were performed in order to investigate the effects of these experimental parameters on global gasification characteristics at elevated pressure. The results shows that the gasification at elevated pressure is more profitable than that at atmospheric pressure considering the carbon conversion and cold gas efficiency. The oxygen/coal ratio at which maximum cold gas efficiency was appeared ranged from 0.5 to 0.7g/g. Only when the temperature is sufficiently high enough, the raise of steam/coal ratio brings improvement of cold gas efficiency. As the pressure increased, the volume of carbon conversion by heterogeneous reaction increased but the volume of carbon conversion by pyrolysis decreased relatively.

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Effects of Different Coal Type on Gasification Characteristics (Pilot 규모 석탄 가스화기에서의 탄종별 가스화성능 특성)

  • Park, Se-Ik;Lee, Joon-Won;Seo, Hea-Kyung
    • Transactions of the Korean hydrogen and new energy society
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    • v.21 no.5
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    • pp.470-477
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    • 2010
  • The IGCC (Integrated gasification combined cycle) is known for one of the highest efficiency and the lowest emitting coal fueled power generating technologies. As the core technology of this system is the gasifier to make the efficiency and the continuous operation time increase, the research about different coal's gasification has been conducted. Our research group had set-up the coal gasifier for the pilot test to study the effect of different coals-Shenhua and Adaro coal- on gasification characteristics. Gasification conditions like temperature and pressure were controlled at a fixed condition and coal feed rate was also controlled 30 kg/h to retain the constant experimental condition. Through this study we found effects of coal composition and $O_2$/coal ratio on the cold gas efficiency, carbon conversion rate. The compounds of coal like carbon and ash make the performance of gasifier change. And carbon conversion rate was decreased with reduced $O_2$/coal ratio. The optical $O_2$/coal ratio is 0.8 for the highest cold gas efficiency approximately. At those operating conditions, the higher coal has the C/H ratio, the lower syn-gas has the $H_2$/CO ratio.

A Numerical Analysis of Flow Field in the Silt Nozzle During Cold Spray Coating Process (저온분사 코팅공정에서 초음속 슬릿노즐 사용시 유동장 해석)

  • Park, Hye-Young;Park, Jong-In;Jung, Hun-Je;Jang, Kyoung-Soo;Baek, Ui-Hyun;Han, Jeong-Whan;Kim, Hyung-Jun
    • Korean Journal of Metals and Materials
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    • v.49 no.3
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    • pp.221-230
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    • 2011
  • The cold spray process is an emerging technology that utilizes high velocity metallic particles for surface coating. Metallic powder particles are injected into a converging-diverging de Laval nozzle and accelerated to a high velocity by a supersonic gas flow. The cold spray process normally uses a circular nozzle that has a rather narrow spraying range. To overcome this fault, a slit nozzle was considered in this study. The slit nozzle is anticipated to reduce the coating process time because it has a wider coating width than the circular nozzle. However, the slit nozzle can reduce the coating efficiency because it does not allow as much gas and particle velocity as the circular nozzle. To improve the coating efficiency of a slit nozzle, the shape of the slit nozzle was modified. And the results of gas flow and particle behaviour according to the nozzlers shape were compared by the a numerical analysis. As a results, as Expansion Ratio(ER) of 7.5 was found to be the most optimal condition for enhancing the spraying efficiency when the ER was changed by the variation of nozzle neck and exit size.

Design and Analysis of Hydrogen Production and Liquefaction Process by Using Liquefied Natural Gas (액화천연가스(LNG)를 사용한 수소 생산 및 액화 공정 개발)

  • Noh, Wonjun;Park, Sihwan;Lee, Inkyu
    • Korean Chemical Engineering Research
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    • v.59 no.2
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    • pp.200-208
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    • 2021
  • Compare to the gaseous hydrogen, liquid hydrogen has various advantages: easy to transport, high energy density, and low risk of explosion. However, the hydrogen liquefaction process is highly energy intensive because it requires lots of energy for refrigeration. On the other hand, the cold energy of the liquefied natural gas (LNG) is wasted during the regasification. It means there are opportunities to improve the energy efficiency of the hydrogen liquefaction process by recovering wasted LNG cold energy. In addition, hydrogen production by natural gas reforming is one of the most economical ways, thus LNG can be used as a raw material for hydrogen production. In this study, a novel hydrogen production and liquefaction process is proposed by using LNG as a raw material as well as a cold source. To develop this process, the hydrogen liquefaction process using hydrocarbon mixed refrigerant and the helium-neon refrigerant is selected as a base case design. The proposed design is developed by applying LNG as a cold source for the hydrogen precooling. The performance of the proposed process is analyzed in terms of energy consumption and exergy efficiency, and it is compared with the base case design. As the result, the proposed design shows 17.9% of energy reduction and 11.2% of exergy efficiency improvement compare to the base case design.

The Design Conditions and the Initial Operation Results of 1 Ton/Day Class Dry Feeding Coal-Gasification System (건식 석탄공급형 1 Ton/Day급 가스화시스템 설계조건 및 시운전결과)

  • Seo, Hai-Kyung;Chung, Jae-Hwa;Ju, Ji-Sun
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.4
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    • pp.352-359
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    • 2009
  • KEPRI is developing a Korean type coal-gasification system and the scale is 20 ton/day. Prior to this pilot plant, a 1 ton/day class gasification system will be used for pre-testing of several coal types. This paper introduces the configuration and design conditions of this 1 ton/day class system, presenting the gas/coal ratio, oxygen/coal ratio, cold gas efficiency, CFD analysis of gasifier, and others. The existing combustion furnace for residual oil was retrofitted as a coal gasifier and a vertical and down-flow type burner was manufactured. Ash removal is carried out through a water quencher and a scrubber following the quencher, and the sulfur is removed by adsorption in the activated carbon tower. The gas produced from the gasifier is burned at the flare stack. In this paper, the results of design conditions and initial operation conditions of I ton/day gasification system are compared together.