Valorization of cotton stalks by fast pyrolysis and fixed bed air gasification for syngas production as precursor of second generation biofuels and sustainable agriculture

In the present study, the potential of cotton stalks utilization for H2 and syngas production with respect to CO2 mitigation, by means of thermochemical conversion (pyrolysis and gasification) was investigated. Pyrolysis was conducted at temperature range of 400–760 °C and the main parametric study concerned the effect of temperature on pyrolysis product distribution. Atmospheric pressure, air gasification at 750–950 °C for various λ (0.02–0.07) was also studied. Experimental results showed that high temperature favors gas production in both processes; while low λ gasification gave high gas yield. Syngas (CO and H2) was increased with temperature, while CO2 followed an opposite trend. By pyrolysis, higher H2 concentration in the produced gas (∼39% v/v) was achieved and at the same time lower amounts of CO2 produced, compared to air gasification.