Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Numerical analysis on performances and emission characteristics of HCCI engine fueled with hydrogen added biogas

반응 메커니즘 기반의 수소 첨가 바이오가스 HCCI 엔진 성능 및 배출가스에 대한 수치 해석적 연구

  • Park, Jungsoo (Department of Mechanical Engineering, Chosun University)
  • 박정수 (조선대학교 기계공학과)
  • Received : 2018.10.01
  • Accepted : 2018.12.07
  • Published : 2018.12.31
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Abstract

In this research, numerical analysis was performed to determine the effects of hydrogen on biogas combustion for homogeneous charged compression ignition (HCCI) engines. The target engine specifications were a 2300cc displacement volume, 13:1 compression ratio, 15kW of electricity, and 1.2 bar boost pressure. The engine speed was fixed to 1800rpm. By varying the excess air ratio and hydrogen contents, the cylinder pressure, nitric oxide, and carbon dioxide were measured as a function of the hydrogen contents. According to preliminary studies related to the reaction mechanism for methane combustion and oxidation, a GRI 3.0 mechanism as the base mechanism was selected for HCCI combustion calculations describing the detailed reaction mechanism. By adding hydrogen, NO was increased while $CO_2$ was decreased. The cylinder pressure was also increased, having advanced timing for the maximum cylinder pressure and pressure rise region. Furthermore, lean operation limits were extended by adding hydrogen to the HCCI engine.

본 연구에서는 바이오가스 기반 예혼합 압축착화(Homogeneous charged compression ignition, HCCI) 엔진에 수소를 첨가하였을 때, 연소실 내부 압력, 온도 배출가스에 미치는 영향에 대해 살펴보았다. 자세히는 수소 첨가량과 과다공기량(${\lambda}$) 변화에 따른 연소실 압력 온도, 그리고 생성물로서의 NO, $CO_2$ 배출 특성을 화학 반응 해석 프로그램을 사용하여 고찰하였다. 대상의 엔진은 2300cc 바이오가스 엔진 발전기로서 압축비 13:1, 발전량 15kW 급이다. 과급압은 1.2bar 고정 조건이며, rpm은 1800rpm의 정속 조건이다. 엔진 연소 방식은 예혼합 압축 착화를 모사하였다. 본 연구를 진행하기에 앞서 바이오가스의 주요 조성인 메탄의 연소 및 산화 메커니즘에 대한 선행 연구에 대한 고찰을 통하여 연소반응 메커니즘을 규명하기 위한 반응 메커니즘 연구 기술의 경향을 살펴보고, 본 연구에 적용 가능한 반응 메커니즘을 선정하여 해석을 진행하였다. 수소를 첨가할 때 NO는 증가하는 반면, $CO_2$등의 배출량은 감소하였고 실린더 내부 압력이 상승하며, 상승 구간이 진각 됨을 알 수 있었다. 또한, 희박영역에서 수소 첨가가 가연 한계를 증가시켰다.

Keywords

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Fig. 1. Calculation process of CHEMKIN

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Fig. 2. Comparison of maximum pressure between experimental and numerical results [6]

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Fig. 3. Fundamental effect of hydrogen addition on cylinder temperature

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Fig. 4. Fundamental effect of hydrogen addition on cylinder pressure

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Fig. 5. Fundamental effect of hydrogen addition on NO mole fraction

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Fig. 6. Fundamental effect of hydrogen addition on CO2 mole fraction

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Fig. 7. NO and CO2 trend as a function of maximum cylinder temperature

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Fig. 8. Maximum pressure changes with various H2 addition and excess air ratio

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Fig. 9. Maximum temperature changes with various H2 addition and excess air ratio

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Fig. 10. NO changes with various H2 addition and excess air ratio

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Fig. 11. Similar trend of NOx emission for varying biogas-hydrogen blends as a function of excess air ratio[6]

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Fig. 12. CO2 changes with various H2 addition and excess air ratio

Table 1. Engine generator specifications

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Table 2. General features of different mechanisms

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Table 3. Variable ranges

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References

  1. R.J. Crookes, "Comparative bio-fuel performance in internal combustion engines", Biomass & Bioenergy, vol, 30, no. 5 pp. 461-468, May, 2006. DOI: https://doi.org/10.1016/j.biombioe.2005.11.022
  2. Z.L. Wei, C.W. Leung, C.S. Cheung, Z.H. Huang,"Effects of equivalence ratio, $H_2$ and $CO_2$ addition on the heat release characteristics of premixed laminar biogas-hydrogen flame", International Journal of Hydrogen Energy, vol, 41, no. 15 pp. 6567-6580, April, 2014. DOI: https://doi.org/10.1016/j.ijhydene.2016.01.170
  3. J. Yue,"Effect of hydrogen addition on performance of low heat value engine", International Journal of Hydrogen Energy, vol, 41, no. 35 pp. 15800-15804, September, 2016. DOI: https://doi.org/10.1016/j.ijhydene.2016.03.172
  4. J. Park, J. Choi, "A numerical investigation of lean operation characteristics of spark ignition gas engine fueled with biogas and added hydrogen under various boost pressures", Applied Thermal Engineering, vol. 117, no.5 pp. 225-234, May, 2017. DOI: https://doi.org/10.1016/j.applthermaleng.2017.01.115
  5. K. Sudheesh, J. M. Mallikarjunaj, "Diethyl ether as an ignition improver for biogas homogeneous charge compression ignition (HCCI) operation - An experimental investigation", Energy, vol. 35, no. 9 pp.3614-3622, September, 2010. DOI: https://doi.org/10.1016/j.energy.2010.04.052
  6. K.T. Lee, T. Kim, S. Song, K.M. Chun,". Generating efficiency and NOX emissions of a gas engine generator fueled with a biogas-hydrogen blend and using an exhaust gas recirculation system", International Journal of Hydrogen Energy, vol. 35, no. 11pp. 5723-5730, June, 2010. DOI: https://doi.org/10.1016/j.ijhydene.2010.03.076