We applied the thermodynamic model developed in this research to compare the equilibrium and experimental mole fraction of the product gases obtained from different bed materials.
Figure 5 illustrates the evolution of the experimental mole fraction of the product gases for various bed materials. Also, a horizontal line indicates equilibrium mole fractions estimated by the thermodynamic model. It must be pointed out that the estimated equilibrium mole fractions of the product gases are expressed on a dry basis to be able to compare them with the experimental data. The Jiggle Bed Reactor let conduct the tests from short to long reaction times. Except for the silica sand for which experiments were also carried out at a reaction time of 600s, …show more content…
This observation indicates the reduced olivine acted as an active and efficient catalyst that exceedingly speeded up the steam gasification reaction, i.e. Equation 14. Since the iron oxide on the olivine surface had been reduced to metallic iron during the reduction pre-treatment with hydrogen, this result proves that metallic iron was responsible for the olivine catalytic activity.
We observed a similar catalytic activity between the reduced olivine and the nickel-based catalysts tested previously [40], i.e. negligible production of hydrocarbons CH4, C2H4 and C2H6 and maximum production of hydrogen. Whereas their production is tiny even at very short reaction times, results in Figure 5 show that hydrocarbons could be fully cracked provided long enough reaction time was available.
The product gases reached the equilibrium state at much longer reaction times during the tests with a bed of the sand. In other words, a reaction time of 600 s was required to reach equilibrium in opposite to the reaction time of 20s necessary for the bed of the reduced olivine. However, it does not mean that sand had any catalytic activity; as explained in the later section, bio-oil conversion with sand was
Figure 5 illustrates the evolution of the experimental mole fraction of the product gases for various bed materials. Also, a horizontal line indicates equilibrium mole fractions estimated by the thermodynamic model. It must be pointed out that the estimated equilibrium mole fractions of the product gases are expressed on a dry basis to be able to compare them with the experimental data. The Jiggle Bed Reactor let conduct the tests from short to long reaction times. Except for the silica sand for which experiments were also carried out at a reaction time of 600s, …show more content…
This observation indicates the reduced olivine acted as an active and efficient catalyst that exceedingly speeded up the steam gasification reaction, i.e. Equation 14. Since the iron oxide on the olivine surface had been reduced to metallic iron during the reduction pre-treatment with hydrogen, this result proves that metallic iron was responsible for the olivine catalytic activity.
We observed a similar catalytic activity between the reduced olivine and the nickel-based catalysts tested previously [40], i.e. negligible production of hydrocarbons CH4, C2H4 and C2H6 and maximum production of hydrogen. Whereas their production is tiny even at very short reaction times, results in Figure 5 show that hydrocarbons could be fully cracked provided long enough reaction time was available.
The product gases reached the equilibrium state at much longer reaction times during the tests with a bed of the sand. In other words, a reaction time of 600 s was required to reach equilibrium in opposite to the reaction time of 20s necessary for the bed of the reduced olivine. However, it does not mean that sand had any catalytic activity; as explained in the later section, bio-oil conversion with sand was