Laminar flame speed of different syngas compositions for varying thermodynamic conditions

Syngas (for synthetic gas) is a well known gaseous biofuel, also known as producer gas or wood gas. It is composed mainly of N2, CO2, CO, H2 and CH4, with varying shares depending on the gasification process and biomass source. When syngas is used in Internal Combustion engines for stationary electricity generation, the operation modes have to be adapted. The problem is that, for the moment, the combustion parameters of complex syngas compositions are not fully covered by the literature. In this study, the laminar flame speeds and Markstein lengths are measured for three syngas compositions. These compositions were chosen to represent typical production of three types of gasifiers (Updraft, Downdraft and Fluidized Bed). Measurements were made at varying initial temperatures (298-423 K), pressures (1-5 bar) and equivalence ratios (0.6-1.4). The method used was the outwardly propagating spherical method. Higher H2 and CO contents on the Updraft and Downdraft compositions produced flame speeds two times higher than the Fluidbed composition. Results were compared to the data from the only two previous studies but no quantitative agreement was found. The results obtained from kinetic modeling with four kinetic mechanisms provide a global agreement specially those from the CRECK mechanism that only deviated from the experimental results by 5-10%.

Automated summary

Syngas, a gaseous biofuel, requires operation mode adaptation when used for stationary electricity generation in Internal Combustion engines. Research indicates that combustion parameters of different syngas compositions from various gasifiers affect flame speeds, with Updraft and Downdraft compositions showing higher speeds. Kinetic modeling results show good overall agreement with experimental data, with CRECK mechanism deviating by only 5-10%.