Experimental study of homogeneous charge compression ignition engine operation fuelled by emulated solid oxide fuel cell anode off-gas

Choi, WooJhon; Kim, Jae Hyun; Kim, Yongtae; Kim, Seonyeob; Oh, Sechul; Song, Han Ho

doi:10.1016/j.apenergy.2018.07.086

Cited by 40 publications

(17 citation statements)

References 30 publications

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“…Compared to previous experimental studies presented by Choi et al 19 the use of SI instead of HCCI combustion mode has several advantages. The direct control of initiating combustion through a spark discharge allows for precise and predictable combustion phasing control.…”

Section: Resultsmentioning

confidence: 97%

“…Choi et al 19 demonstrated that SOFC anode off-gas can be used as fuel in an ICE engine operating in homogeneous charge compression ignition (HCCI) mode, with a minimal amount of nitrogen oxide (NO x ) and total hydrocarbon (THC) emissions. Another SOFC-HCCI hybrid system for power generation was modeled by Zhu et al 20 who predicted an energy conversion efficiency of 65.7%.…”

Section: Introductionmentioning

confidence: 99%

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Investigating anode off-gas under spark-ignition combustion for SOFC-ICE hybrid systems

Ran

Longtin

Assanis

2021

International Journal of Engine Research

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Solid oxide fuel cell – internal combustion engine (SOFC-ICE) hybrid systems are an attractive solution for electricity generation. The system can achieve up to 70% theoretical electric power conversion efficiency through energy cascading enabled by utilizing the anode off-gas from the SOFC as the fuel source for the ICE. Experimental investigations were conducted with a single cylinder Cooperative Fuel Research (CFR) engine by altering fuel-air equivalence ratio (ϕ), and compression ratio (CR) to study the engine load, combustion characteristics, and emissions levels of dry SOFC anode off-gas consisting of 33.9% H2, 15.6% CO, and 50.5% CO2. The combustion efficiency of the anode off-gas was directly evaluated by measuring the engine-out CO emissions. The highest net-indicated fuel conversion efficiency of 31.3% occurred at ϕ = 0.90 and CR = 13:1. These results demonstrate that the anode off-gas can be successfully oxidized using a spark ignition combustion mode. The fuel conversion efficiency of the anode tail gas is expected to further increase in a more modern engine architecture that can achieve increased burn rates in comparison to the CFR engine. NOx emissions from the combustion of anode off-gas were minimal as the cylinder peak temperatures never exceeded 1800 K. This experimental study ultimately demonstrates the viability of an ICE to operate using an anode off-gas, thus creating a complementary role for an ICE to be paired with a SOFC in a hybrid power generation plant.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Investigating anode off-gas under spark-ignition combustion for SOFC-ICE hybrid systems

Ran

Longtin

Assanis

2021

International Journal of Engine Research

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“…All identified research articles classified under different modes of combustion (MoCs) involving SI, SAI, HCCI, and RCCI, as adapted from. 13,18,22,25,26,[31][32][33][34][35][36][37][38][39] intermittency issues, linked to popular renewable energy (RE) technologies, such as wind turbines (WTs) and photovoltaic (PV) panels, are being dealt with hybridization with SOFC subsystems. Therefore, the particular type of systems should probably be favored over aforementioned stand-alone RE practices, at least in terms of stable and uninterrupted operation.…”

Section: Introductionmentioning

confidence: 99%

“…The increased cost of the particular technology nevertheless should be considered, 20 even when expensive catalysts, frequently associated to its operation, were not deployed in the majority of cases. 31 In terms of the ICE subsystems being integrated in the studied hybrid layouts, piston engines were implemented and rigorously examined in both computational and experimental frameworks. In detail, multiple modes of combustion were considered, enhancing system flexibility in operation, among which the most dominant was identified in homogeneous charge compression ignition (HCCI).…”

Section: Introductionmentioning

confidence: 99%

“…In detail, multiple modes of combustion were considered, enhancing system flexibility in operation, among which the most dominant was identified in homogeneous charge compression ignition (HCCI). 13,18,22,25,26,[31][32][33][34][35] Other modes involved all spark ignition (SI), [36][37][38][39] spark-assisted ignition (SAI), 18 as well as reactivity-controlled compression ignition (RCCI). 13 Evidently, low temperature combustion (LTC) was extensively assessed, with the majority of researchers investigating leaner mixtures, 22,25 as illustrated in Figure 1 and in certain cases across multiple compression ratios (CRs).…”

Section: Introductionmentioning

confidence: 99%

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Investigating realistic anode off-gas combustion in SOFC/ICE hybrid systems: mini review and experimental evaluation

Nikiforakis

Ran

Sprengel³

et al. 2021

International Journal of Engine Research

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Solid oxide fuel cells (SOFCs) have been deployed in hybrid decentralized energy systems, in which they are directly coupled to internal combustion engines (ICEs). Prior research indicated that the anode tailgas exiting the SOFC stack should be additionally exploited due to its high energy value, with typical ICE operation favoring hybridization due to matching thermodynamic conditions during operation. Consequently, extensive research has been performed, in which engines are positioned downstream the SOFC subsystem, operating in several modes of combustion, with the most prevalent being homogeneous compression ignition (HCCI) and spark ignition (SI). Experiments were performed in a 3-cylinder ICE operating in the latter modus operandi, where the anode tailgas was assimilated by mixing syngas (H2: 33.9%, CO: 15.6%, CO2: 50.5%) with three different water vapor flowrates in the engine’s intake. While increased vapor content significantly undermined engine performance, brake thermal efficiency (BTE) surpassed 34% in the best case scenario, which outperformed the majority of engines operating under similar operating conditions, as determined from the conducted literature review. Nevertheless, the best performing application was identified operating under HCCI, in which diesel reformates assimilating SOFC anode tailgas, fueled a heavy duty ICE (17:1), and gross indicated thermal efficiency ([Formula: see text]) of 48.8% was achieved, with the same engine exhibiting identical performance when operating in reactivity-controlled compression ignition (RCCI). Overall, emissions in terms of NOx and CO were minimal, especially in SI engines, while unburned hydrocarbons (UHC) were non-existent due to the absence of hydrocarbons in the assessed reformates.

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Solid oxide fuel cell and advanced combustion engine combined cycle: A pathway to 70% electrical efficiency

Chuahy

Kokjohn

2019

Applied Energy

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Experimental study of homogeneous charge compression ignition engine operation fuelled by emulated solid oxide fuel cell anode off-gas

Cited by 40 publications

References 30 publications

Investigating anode off-gas under spark-ignition combustion for SOFC-ICE hybrid systems

Investigating anode off-gas under spark-ignition combustion for SOFC-ICE hybrid systems

Investigating realistic anode off-gas combustion in SOFC/ICE hybrid systems: mini review and experimental evaluation

Solid oxide fuel cell and advanced combustion engine combined cycle: A pathway to 70% electrical efficiency

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