Biomass Catalytic Steam Gasification Thermodynamics Analysis and Reaction Experiments in a CREC Riser Simulator

Abstract

A thermodynamic equilibrium model based on evaluations involving C, H, and O element balances and various product species up to C 6 hydrocarbons is reported in this study. This model establishes the effects of biomass composition, temperature, and steam on the various gas product molar fractions. On this basis, most significant parameters determining the chemical interconversions and distribution of chemical species are identified. On the basis of the proposed equilibrium model and using glucose as a model biomass species [C 6 H 12 O 6 ], an optimum gasification temperature close to 800 °C and a steam/biomass ratio between 0.5 and 0.7 g/g is established. This study has the special value of comparing thermodynamic equilibrium predictions with experimental data obtained in a CREC riser simulator using a fluidizable Ni-Al 2 O 3 catalyst. Results are relevant for scaled-up gasifiers. They show that for reaction times longer than 30 s chemical species are essentially equilibrated and that the proposed model does provide adequate description of various product fractions. Data obtained also demonstrate the shortcomings of equilibrium models for gasifiers with reaction times shorter than 10 s and the need for nonequilibrium models to describe gasifier performance at such conditions.

CO2 biomass fluidized gasification: Thermodynamics and reactivity studies

“…This GC unit contains a thermal conductivity detector (TDC) and a flame ionization detector (FID). TCD calibration curves are used for the quantification of permanent gases and light hydrocarbons …”

“…Data input to the model are based on several sound assumptions: The gasifier operates isothermally under steady state conditions. These are the conditions anticipated in a fluidized bed gasifier. Biomass composition can be divided up into carbon, hydrogen, and oxygen constitutive elements, in accordance with its elemental analyses. Other elements present in biomass, such as sulphur and nitrogen, can be neglected given that they are present in small quantities. The main biomass gasification products are hydrogen, carbon monoxide, carbon dioxide, methane, and water vapour. The produced solid char can be considered as 100 % carbon and does not react or act as a catalyst. The char and tar are accounted for as unconverted carbon. The biomass particle size is assumed to be small enough such that mass and heat transport limitations can be neglected. …”

Haber process and steam‐coal gasification: Two standard thermodynamic problems elucidated using two distinct approaches

“…Table 1 shows the chemical reactions taking place in the steam-coal gasification process [19]. All limitations of the reaction coordinatesequilibrium constants method apply.…”

“…Indeed, there is a plethora of reactions and a solid-phase component is involved in the reaction scheme. Table 1 shows the chemical reactions taking place in the steam-coal gasification process [19].…”

Diffusion and Equilibrium Adsorption Coefficients of Aromatic Hydrocarbon Species in Capillary Columns

“…For instance, The European Tar Protocol by The IEA Bioenergy Gasification Task and The European Commission (DG XVII) suggest the value of the characterization of aromatic tar compounds using analytical systems with a capillary glass tube coated with poly (5%diphenyl/95%dimethylsiloxane) or similar ones [21,22]. This type of capillary columns have been employed by a significant number of authors [23][24][25][26][27].…”