Gasification of Wood Char in Single and Mixed Atmospheres of H₂O and CO₂

Abstract

In gasification processes, char-H 2 O and char-CO 2 are the main heterogenous reactions that are responsible for carbon conversion into H 2 and CO. These two reactions are generally looked at independently without considering interactions between them. The objective of this work was to compare kinetics of each reaction alone to kinetics of each reaction in a mixed atmosphere of H 2 O and CO 2. A char particle was gasified in a macro thermo gravimetry reactor at 900 ı C successively in H 2 O/N 2 , CO 2 /N 2 , and H 2 O/CO 2 /N 2 atmospheres.

Investigation on gasification of coffee husk inCO2,H2O, and mixed atmospheres

“…Thus, the CO2 gasification rate was nearly twice slower than that of steam gasification at 900 o C. This result is similar to the literature results for wood char, showing that gasification with CO2 was 2 to 5 times slower than with H2O under the same conditions. [25] Therefore, coffee husk could be a potential feedstock for replacing wood chips in gasification systems. The char reactivity in different atmospheres was presented in the conversion range between 10 and 90 % (figure 4b).…”

Steam Gasification of Bagasse: Effect of Heating Rate

“…In addition, a number of operating parameters can affect the gasification of biomass, such as gasifying temperature, partial pressure of the reacting gas, and heating rate [8]. Among them, the heating rate is particularly important.…”

The effects of textural modifications on beech wood-char gasification rate under alternate atmospheres of CO 2 and H 2 O

“…Owing to these findings, there may be synergistic effects between the two gasses and enhanced internal diffusivity as proposed previously for mixed atmosphere gasification in H 2 O and CO 2 [15][16][17]. In this work, the main purpose is to study the mutual influences of H 2 O and CO 2 on the char gasification reactivity, and to evaluate the impact of a prior gasification with CO 2 on the char reactivity to H 2 O and vice versa.…”

“…Recent investigations showed that the char reactivity in a mixed atmosphere of H 2 O and CO 2 is higher than the sum of the individual reactivities [15][16][17]. These authors mentioned that there is synergy between the two gasses resulting from the creation of a wider porosity by CO 2 facilitating the access of H 2 O to the active sites:…”

“…For instance, some authors think that CO 2 would create a wider porous network that facilitates the access of H 2 O to the carbon active sites and would therefore enhance the gasification reaction [15][16][17].…”