Internacional

Prediction and measurement of the critical compression ratio and methane number for blends of biogas with methane, propane and hydrogen

Methane number (MN) and the critical compression ratio (CCR) measurements for twelve blends of biogas with methane or propane and hydrogen additions were taken in a Cooperative Fuel Research (CFR) F2 model engine according to the standard. In addition, CHEMKIN simulations of MN and the CCR were performed on these blends at similar conditions to the CFR F2 engine operation. Eight chemical kinetics mechanisms were used; it was concluded that the best mechanism to simulate the CCR is USCII, and the best mechanism to simulate MN is San Diego.

Direct emissions of nitrous oxide from combustion of gaseous fuels

International Journal of Hydrogen Energy

After molecular nitrogen, nitrous oxide (N2O) is the second most abundant nitrogen compound in the atmosphere and its concentration is rising at rate of 0.26% yr−1 (0.7 ppb yr−1). In the troposphere N2O is a relatively stable compound, however it is reactive in the stratosphere, where it is destroyed by photolysis with ultraviolet radiation. While photolysis in the stratosphere removes this potent greenhouse gas from the atmosphere, subsequent reactions also destroy protective ozone.

Numerical and experimental analysis of the effect of adding water electrolysis products on the laminar burning velocity and stability of lean premixed methane/air flames at sub-atmospheric pressures

This paper presents a study of CH4/Air/H2/O2 premixed laminar flames using a ratio of H2/O2 equal to 2/1. This gas mixture represents the products of the electrolysis of water. To date, only numerical analysis has been carried out on these kinds of blends and using H2/O2 percentages of only up to 10% by volume. Furthermore, there have been no reports of experimental analysis or possible flame instabilities associated with the enrichment of the mix with H2/O2.

Theoretical, experimental and numerical study of infrared radiation heat transfer in a drying furnace

This paper aims at the study of thermal radiation heat transfer in a drying furnace considering: heating surfaces, reflector shield and load material for three power levels: 27 kW, 41 kW and 55 kW. An algorithm was developed to calculate the energy rate transferred to the load by radiation, the heat losses, and the radiation efficiency. The algorithm was validated with an experimental setup.

Experimental study of spark ignition engine performance and emissions in a high compression ratio engine using biogas and methane mixtures without knock occurrence

With the purpose to use biogas in an internal combustion engine with high compression ratio and in order to get a high output thermal efficiency, this investigation used a diesel engine with a maximum output power 8.5 kW, which was converted to spark ignition mode to use it with gaseous fuels. Three fuels were used: Simulated biogas, biogas enriched with 25% and 50% methane by volume. After conversion, the output power of the engine decreased by 17.64% when using only biogas, where 7 kW was the new maximum output power of the engine.

Performance study of an induced air porous radiant burner for household applications at high altitude

Porous radiant burners are presented as an alternative technology for improving the thermal efficiency of conventional burners. A performance study of an induced air porous radiant burner (IAPRB) with submerged combustion using natural gas was performed at high altitude to assess the feasibility of employing a porous burner operated with induced air in household applications. The experiments were performed in two-layer porous media. The preheating and combustion zones consisted of 400 ppi alumina honeycomb and 90% porosity silicon carbide foam, respectively.

Combustion analysis of an equimolar mixture of methane and syngas in a surface-stabilized combustion burner for household appliances

The primary objective of this work is to study the combustion of an equimolar mixture of methane and syngas (CH4–SG) in a ceramic surface-stabilized combustion burner. We examine the effects of the fuel composition, the air-to-fuel ratio and the thermal input on the flame stability, the radiation efficiency and the pollutant emissions (CO and NOx). In this study, we evaluate a syngas with a high hydrogen content that is similar to those obtained by coal gasification (50–60% H2) using Sasol/Lurgi gasification technology and biomass gasification, for example.

Numerical and experimental methodology to measure the thermal efficiency of pots on electrical stoves

In this paper, we present a methodology for calculating the thermal efficiency of a pot on an electric stove using numerical simulations in ANSYS FLUENT®. The system domain was divided into three subsystems: electrical resistors, the air volume inside the resistors, and the pot. It was determined that the heat transfer to the pot was mainly caused by conduction between the heating element and the pot surface, representing 85.7% of the total energy going into the system. Heat transfer by convection and radiation represented 13% and 1.3% of the total incoming energy, respectively.

Numerical and experimental study on laminar burning velocity of syngas produced from biomass gasification in sub-atmospheric pressures

The laminar burning velocity of syngas mixtures has been studied by various researches. However, most of these studies have been conducted in atmospheric conditions at sea level. In the present study, the effect of sub atmospheric pressure was evaluated on the laminar burning velocity for a mixture of H2, CO and N2 (20:20:60 vol%) in real sub atmospheric condition.

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