Gasification of Oil-Palm Fiber Using Pure Oxygen, Pure Steam, and Oxygen-Steam Mixtures as Oxidizing Agent Available to Purchase

The increasing concern for greenhouse emissions from fossil fuel combustion processes has encouraged the research on technologies that use alternative fuels. A feasible option is the use of biomass feedstock to produce gaseous and liquid fuels via thermal gasification. This is promising since biomass has net zero carbon footprint. Colombian oil-palm agroindustry produces a great amount of fiber wastes (mesocarp of the oil palm fruit), which, in many cases, can pollute natural sources (including global warming by way of potent greenhouse emissions such as CH₄) due to the fact that waste handling systems, storage, and treatment structures are frequently not appropriate. Nevertheless, the concentration of this fiber in oil factories makes this resource a viable feedstock for local thermal gasification facilities. The current paper deals with oil-palm fiber (fruit mesocarp) thermal gasification (including pyrolysis) using oxygen, steam, and oxygen-steam mixtures for partial oxidation. The Chemical Equilibrium with Applications program (CEA), developed by NASA, was used to estimate the compositions of the gaseous fuels produced from pyrolysis, steam reforming and oxygen-steam adiabatic gasification. Based on gas composition, the energy densities of gaseous fuels produced along with the energy recoveries for all gasification process were also calculated. Operating parameters such equivalence ratio (Φ) and steam to fuel ratio (SF) were studied for adiabatic oxygen-steam gasification while temperature (T) and pressure were studied for non-adiabatic gasification (steam reforming (Φ = 0), and pyrolysis (Φ= 0 and SF = 0)). The effect of SF on pure steam gasification was also studied. In order to estimate the pyrolysis activation energy, thermogravimetric analyses (TGA) were carried out using N₂ as carrier gas and under different heating rates (β: 10, 20, and 30 °C/min). Results from oxygen-steam gasification showed that at Φ < 3, increased Φ (less oxygen supplied) increases the production of H₂ and CO but decreases the production of CO₂. At Φ >3, increased Φ produces mixtures rich in H₂ and CO₂ but poor in CO. The productions of CO and H₂ from pyrolysis and steam reforming are only possible at T between 700 K and 1100 K. At T > 1100 K, the effect of temperature on H₂ and CO productions is negligible; however, under those operating conditions (T > 1100 K), increased SF results in mixtures composed basically of H₂, CO, and low traces of CO₂. The average value of the activation energy was 233 kJ/kmol.