Enriched Compressed Natural Gas Research Articles

Green Hydrogen-Compressed natural gas (bio-H-CNG) production from food waste: Organic load influence on hydrogen and methane fusion

Biogenic hydrogen (bioH2) enriched compressed natural gas (bio-H-CNG or biohythane) is emerging interest due to its feasibility to use in the existing transportation infrastructure with induced environmental benefits. This study evaluated the production of bioH2and biomethane (bioCH4) towards bio-H-CNG formation at a varying organic load (OL: 30,40,50 g COD/L) of food waste (FW). Acidogenic reactor operated with FW at 40 g COD/L showed the highest cumulative bioH2production while elevated OL (50 g COD/L)showedhigher cumulative bioCH4production (CMP: 11.92 L) from the methanogenic reactor. BioH2 and bioCH4 produced at different time intervals were combined to assess bio-H-CNG. The nature of biocatalyst and OLsignificantly regulated the composition of bio-H-CNG varying between 0.1 and 0.3 of H2/(H2+CH4) ratio accounting for5–12.6 kJ/g COD. Chain elongation, converting short (C2-C4) to medium-chain fatty acids(Caproic acid,1.16 g/L) was specifically observed during the acidogenic process.

Dual fuel engines fueled with three gaseous and biodiesel fuel combinations

ABSTRACTAlternative fuels have numerous advantages over fossil fuels as they are renewable, biodegradable, provide energy security and foreign exchange savings, and help in addressing environmental concerns and socio-economic issues. Renewable fuels such as biodiesel and gaseous fuels can be used for transportation and power generation applications. Honge oil methyl ester (HOME) biodiesel and three gaseous fuels – compressed natural gas (CNG), hydrogen enriched compressed natural gas (HCNG), and producer gas – were used as injected and inducted fuels. This paper presents the performance, combustion and emission characteristics of a single-cylinder, four-stroke direct injection stationary diesel engine operated in dual fuel mode on a combination of HOME and the gaseous fuels CNG, HCNG and producer gas. For a diesel engine operated in dual fuel mode with HOME–gaseous fuel combinations, experimental results showed decreased brake thermal efficiency, smoke and nitric oxide emission levels and increased hydrocarbon and carbon monoxide emission levels when compared with single fuel mode of operation. Compared to CNG and producer gas dual fuel operation, HCNG operation resulted in overall improved performance (with HOME being the common fuel in all dual fuel modes of operation). Enriched CNG with hydrogen (20%) i.e. HCNG improved the dual fuel engine performance with HOME when compared to CNG operation.