Comparative life cycle environmental and cost assessments of renewable natural gas production pathways

Kotagodahetti, Ravihari; Hewage, Kasun; Razi, Faran; Sadiq, Rehan

doi:10.1016/j.enconman.2023.116715

Cited by 8 publications

(1 citation statement)

References 45 publications

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“…Now, RNG has become popular in North America and Europe due to its economic potential [7][8][9]. However, the current resources for RNG are insufficient, and a series of issues about how to establish the viability of integrating RNG into the gaseous fuel industry need to be addressed [10]. Therefore, RNG utilization in localities can be regarded as another solution.…”

Section: Introductionmentioning

confidence: 99%

Study on Hydrogen Direct Injection in RNG Combustion under Various Ignition Timings for Power Generation in a Retrofitted Gas Engine

Yu,

Luo,

Zhou

et al. 2024

Processes

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Renewable natural gas (RNG) is attractive for energy policy goals in the world. Therefore, a regional system is designed to explore RNG combustion for power generation in localities. This study investigates a direct injection (DI) engine fueled with hydrogen (H2) blended into the simulated renewable natural gas, which consists of 50% methane (CH4) and 50% carbon dioxide (CO2) in volume. In order to obtain higher efficiency, comparisons between DI and port fuel injection (PFI) of H2 addition were made. Then, the volume percentage of H2 was changed from 20% to 100% by keeping the volume ratio of CH4 and CO2 at 1:1. Finally, results of power output, brake mean effective pressure (BMEP), brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) were discussed. Results showed that in contrast to PFI, H2 DI injection could increase efficiency by 4%. Additionally, H2 DI could retard the MBT ignition timing at 5 °CA. Compared with CH4/CH4 + CO2 combustion, under stoichiometric combustion, BMEP increases with H2 addition but BTE decreases significantly. However, by enlarging the excess air ratio (λ) to 1.24, both BMEP and BTE increase obviously with H2 addition. Moreover, when λ < 1.3, the MBT ignition timing should be advanced from −10 to 15 °CA top dead center (TDC). But the MBT ignition timing is fixed at −25 °CA TDC when λ is larger than 1.3. Furthermore, if efficiency is the priority, 30% H2 addition with λ at 1.24 (−15 °CA TDC) should be selected. If higher BMEP is preferred, 20% H2 addition with λ at 0.99 (−10 °CA TDC) should be selected.

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