Recent advances in sustainable drying of agricultural produce: A review

Investigation into SI engine performance characteristics and emissions fuelled with ethanol/butanol-gasoline blends

Italy is one of the leading nations in the biogas sector. Agricultural, landfill, sewage and manure substrates are converted into biogas using anaerobic digestion and, then, into electricity and heat by means of properly arranged internal combustion engines. In this study, after an overview of the European context, the authors present the Italian biogas sector status in terms of development trends and factors that favour/block biogas spread. Despite the fact that biogas is a renewable fuel and a consolidate technology, it is mandatory to examine its real costs, biogas composition and engine combustion products. For this purpose, in the present work, the authors selected six in-operation biogas plants fed by different substrates, investigate plants construction and operation costs and measure both biogas and engine emissions compositions. Biogas status analysis shows a high growth rate until the end of 2012 due to generous Government subsidies while, after supports reduction, a continuous depletion of biogas installations is observed. Alongside the development, established supports overlook also the plant size as well as the cost. In fact, the most widespread plant nameplate electric power is 1 MW while its construction cost ranges between 4.2–4.8 millions of Euros. Real on-site measurements show variable biogas composition while engine emissions are comparable with the natural gas ones.

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Italian Biogas Plants: Trend, Subsidies, Cost, Biogas Composition and Engine Emissions

Combustion and emission characteristics of isoamyl alcohol-gasoline blends in spark ignition engine

Experimental investigation on the potential of biogas/ethanol dual-fuel spark-ignition engine for power generation: Combustion, performance and pollutant emission analysis

Comparative assessment of a spark ignition engine fueled with gasoline and raw biogas

Ignition timing and compression ratio as effective means for the improvement in the operating characteristics of a biogas fueled spark ignition engine

In the current investigation, raw biogas obtained from rural sectors was used as the alternative to gasoline fuel in the spark ignition (SI) engine. The performance and efficiency are mainly depend...

Ignition advancement study for optimized characteristics of a raw biogas operated spark ignition engine

The usage of biogas as a potential fuel in a spark ignition (SI) engine is the theme for the present study. The exhaust gas recirculation (EGR) is a significant technique for improving the performance of the SI engine. Thus, the novelty of the experimental investigations lies in implementing the EGR technique for emission control of the biogas-fueled engine. The raw biogas (52% methane and 47% carbon dioxide), obtained from a biogas digester (using cow dung as the source), was the engine fuel for a four stroke, water cooled, variable compression ratio SI engine set-up. Here, the engine performance and emission related parameters were measured. When operated in the raw biogas mode at an optimum spark timing of 45 °CA before the top dead center, the engine produced maximum torques of 11 N m, 14 N m, and 16 N m for compression ratios 8, 9, and 10, respectively. The effect of different EGR rates on the emission control was also investigated. The net heat release rate without EGR was found to be 22.623J/°CA at 368 °CA, which further reduced to 14.233 J/°CA at 386 °CA for EGR10. Moreover, it was clearly evident that low EGR rates (below 10%) were effective in reducing NOX significantly, with minor compromise in power and brake specific fuel consumption. But the emissions of hydrocarbon and carbon monoxide were found to be higher with the increase in EGR. The operation of the engine with medium or heavy EGR rates resulted in issues related to intense pressure fluctuations and large cycle-to-cycle variation in performance. Thus, the present investigations recommend the use of low EGR (below 10%) in a biogas-based engine for lower NOX emission and better fuel efficiency.

Santosh Kumar Hotta

Papers

Comparative assessment of a spark ignition engine fueled with gasoline and raw biogas

Ignition timing and compression ratio as effective means for the improvement in the operating characteristics of a biogas fueled spark ignition engine

Ignition advancement study for optimized characteristics of a raw biogas operated spark ignition engine

Combined impact of compression ratio and re-circulated exhaust gas on the performance of a biogas fueled spark ignition engine

Effect of Waste Heat Recovery on Drying Characteristics of Sliced Ginger in a Natural Convection Dryer