Hydrogen production from biomass and plastic mixtures by pyrolysis-gasification

Abstract

The addition of plastics to the steam pyrolysis/gasification of wood sawdust with and without a Ni/Al 2 O 3 catalyst was investigated in order to increase the production of hydrogen in the gaseous stream. To study the influence of the biomass/plastic ratio in the initial feedstock, 5, 10 and 20 wt. % of polypropylene was introduced with the wood in the pyrolysis reactor. To investigate the effect of plastic type, a blend of 80 wt. % of biomass and 20 wt. % of either polypropylene, high density polyethylene, polystyrene or a mixture of real world plastics was fed into the reactor. The results showed that a higher gas yield (56.9 wt.%) and a higher hydrogen concentration and production (36.1 vol.% and 10.98 mmol. H 2 g -1 sample, respectively) were obtained in the gaseous fraction when 20 wt. % of polypropylene was mixed with the biomass. This significant improvement in gas and hydrogen yield was attributed to synergetic effects between intermediate species generated via co-pyrolysis. TheNi/Al 2 O 3 catalyst dramatically improved the gas yield as well as the hydrogen concentration and production due to the enhancement of water-gas-shift and steam reforming reactions.Very low amounts of coke (less than 1 wt. % in all cases) were formed on the catalyst during reaction, with the deposited carbonaceous material being of the filamentous type. The Ni/Al 2 O 3 catalyst was shown to be effective one hydrogen production in the copyrolysis/gasification process of wood sawdust and plastics.

Carbon nanotubes and hydrogen production from the pyrolysis catalysis or catalytic-steam reforming of waste tyres

“…Reduction of the catalyst occurred in-situ by the generated process gases, particularly hydrogen and carbon monoxide [27].…”

Raw and steam exploded pine wood: Possible enhanced reactivity with gasification hydrogen

“…Steam reforming of coal and biomass can be used for the production of hydrogen and if the CO is converted to CO2 and the total CO2 solvent extracted and captured, then low carbon hydrogen can be generated from coal or biomass [3][4][5]. In the combustion of rich mixtures of biomass, as studied in this work, the equilibrium products are essentially those of a gasification process with high CO and H2 [6].…”

Effect of Ni/Al2O3-SiO2and Ni/Al2O3-SiO2with K2O Promoter Catalysts on H2, CO and CH4Concentration by CO2Gasification ofRosa MultifloraBiomass

“…Hence, it can be concluded that Ni/ Generally, the process of gasification is favored by the high temperature which amplifies the secondary hydro cracking and shifts the reactions to conversion of hydrocarbons (C n H 2n ). This particular fact might be because of the contribution of the reforming reactions which are favored and occurred at high temperature, hence becoming prevailing at temperatures which are higher than 800°C [43][44][45][46][47][48][49][50]. The finite gas composition is a function of the common reactions that at the same time come off by increasing the synthesis gas yields connected with the conversion of tar into synthesis gas.…”