Biogas upgrade through exhaust gas reforming process for use in CI engines

Lau, Chia Sheng (2012). Biogas upgrade through exhaust gas reforming process for use in CI engines. University of Birmingham. Ph.D.

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Abstract

Biogas is not ideal for combustion in diesel engines mainly due to its low energy content. The upgrading of biogas into high quality syngas through catalytic reforming reactions was investigated. Studies on the effect of temperature, space velocity and O\(_2\)/CH\(_4\) molar ratio on various basic biogas reforming processes were done. The dry reforming of biogas was found to be active at high reactor temperatures with syngas production and reduction of carbon dioxide. The promotion of simultaneous dry and oxidative reforming by adding oxygen improves syngas production at conditions of low temperature and high space velocity. Subsequently, the biogas exhaust fuel reforming process was done by feeding real engine exhaust together with biogas into the reforming reactor. Reforming process efficiency of 95% (ratio of energy content of reformate to biogas) was achieved at high space velocity and high content of steam in exhaust at medium engine load (300°C exhaust temperature). Further improvement was observed when reformed exhaust gas recirculation (REGR) was applied due to increased exhaust steam content in the engine – reactor system which promoted the endothermic steam reforming reaction. Moreover, improved engine thermal efficiency and lower emissions were found during reformate gas-diesel operation compared to biogas-diesel operation.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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