Sustainable syngas and H2 from a zootechnical waste: an investigation on fluidized bed gasification of cattle manure.

Cattle manure (CM) is a zootechnical waste no longer desired for direct land application. Therefore, alternative methods of disposal must be developed, especially in countries with high production of dairy products and meat. Fluidized bed gasification allows for the safe utilization of manure together with the recovery of energy in the form of syngas. In the presented research, CM was subjected to fluidized bed gasification in CO2 and O2 atmospheres at T = 850 °C. Different CO2 levels (YCO2 = 0.10, 0.20, and 0.30) or equivalence ratios for O2 (χ = 0.3, 0.4, and 0.5) were used during gasification tests at laboratory scale. For the CO2 atmosphere, the gas yields of H2, CH4, and CO were the highest at YCO2 = 0.30 with a conversion degree of 73.7 % and maximum cold gas efficiency of 83.1 %. For O2 atmosphere, the conversion degree of 86.4 % and maximum cold gas efficiency of 60.0 % were achieved at lowest equivalence ratio (χ = 0.3). An exploratory test confirmed the advantage of using a catalytic bed material (dolomite) compared to an inert one (quartzite). The presence of dolomite led to increased levels of H2 and CH4. Tar yield and characteristics for CM and reference beech wood (BW) were similar, although a slightly larger amount was appreciated for CM.