193
7.3.2 Effect of Gas Space Velocity per Gram of Catalyst
(GSVC)
Effect of velocity of inlet gas per gram of catalyst used has not been widely studied,
and only few literatures are focusing on this parameter. Mohd Arif et al. (2018) have
studied the effect of gas hourly specific velocity (GHSV) over Re/Ni − CaO at
800 °C with ratio CO 2 -to-glycerol of 3. They observed that an increase of GHSV
favors the conversion of glycerol as well as carbon monoxide and hydrogen yield. It
is mainly due to lower residence time that limits the reactant and catalyst active sites
to react. From their finding, the highest glycerol conversion (61%) and yield of
hydrogen (56%) over Re/Ni − CaO were found at GHSV of 3.6 x 10
4
ml g
−1 cat s
−1
.
Reaction of GDR operating at more than 3.6 × 10
4
ml g
−1 cat s
−1
would give a negative
effect towards the reforming process (X glycerol = 28%, Y H2 = 16%, Y CO = 37%). In
addition, it will contribute more on coke formation (Mohd Arif et al. 2018).
Harun et al. (2019) recently studied the effect of gas space velocity which is
represented in weight hourly space velocity (WHSV) in the range of 14.4 × 10 L g
−1 cat
h
−1
to 72 L g
−1 cat h
−1
over Al 2 O 3 -based catalyst for GDR. It was found that the glycerol conversion increased with the increase of WHSV up to 72 L g
−1 cat h
−1
with
41.09% of glycerol conversion. Further increase in WHSV led to decline of glycerol
conversion due to the limitation of active sites as less catalyst weight was introduced. Moreover, the lowest WHSV would reduce the glycerol conversion and
hydrogen yield as more metal active sites were exposed to the intermediate species
of reaction which would favor the carbon formation and led to deterioration of catalyst (Harun et al. 2019; Pairojpiriyakul et al. 2014).
7.3.3 Effect of Molar Ratio of Carbon Dioxide-to-Glycerol
GDR is a reaction between one mole of glycerol with one mole of CO 2 to produce
syngas consists of CO and H 2 and water as shown in Eq. (7.2). From the overall
main reaction of GDR, CO 2 -to-glycerol of 1 is an ideal thermodynamic conditions
to achieve high yield of syngas. Wang et al. (2009) reported that at 727 °C of operating temperature with CO 2 -to-glycerol ratio of 1 was found as the optimum condition
to reach maximum yield of hydrogen. However, many researchers have been investigated the effect of CO 2 -to-glycerol towards the product yield (Tavanarad et al.
2018; Bulutoglu et al. 2018; Harun et al. 2019).
Bulutoglu et al. (2018) have studied the influence of CO 2 -to-glycerol ratio within
0–4 over Rh − ZrO 2 and Rh − CeO 2 catalysts at 750 °C towards the syngas product
yield. From their observation, ~96% of glycerol conversion was achieved with
presence of glycerol only with no CO 2 inlet was introduced (CO 2 -to-glycerol = 0).
Meanwhile, the glycerol conversion decreases around 30% along with the increasing CO 2 -to-glycerol ratio from 0 to 4 at constant reaction temperature (Bulutoglu
7 A Short Review on Production of Syngas via Glycerol Dry Reforming
7.3.2 Effect of Gas Space Velocity per Gram of Catalyst
(GSVC)
Effect of velocity of inlet gas per gram of catalyst used has not been widely studied,
and only few literatures are focusing on this parameter. Mohd Arif et al. (2018) have
studied the effect of gas hourly specific velocity (GHSV) over Re/Ni − CaO at
800 °C with ratio CO 2 -to-glycerol of 3. They observed that an increase of GHSV
favors the conversion of glycerol as well as carbon monoxide and hydrogen yield. It
is mainly due to lower residence time that limits the reactant and catalyst active sites
to react. From their finding, the highest glycerol conversion (61%) and yield of
hydrogen (56%) over Re/Ni − CaO were found at GHSV of 3.6 x 10
4
ml g
−1 cat s
−1
.
Reaction of GDR operating at more than 3.6 × 10
4
ml g
−1 cat s
−1
would give a negative
effect towards the reforming process (X glycerol = 28%, Y H2 = 16%, Y CO = 37%). In
addition, it will contribute more on coke formation (Mohd Arif et al. 2018).
Harun et al. (2019) recently studied the effect of gas space velocity which is
represented in weight hourly space velocity (WHSV) in the range of 14.4 × 10 L g
−1 cat
h
−1
to 72 L g
−1 cat h
−1
over Al 2 O 3 -based catalyst for GDR. It was found that the glycerol conversion increased with the increase of WHSV up to 72 L g
−1 cat h
−1
with
41.09% of glycerol conversion. Further increase in WHSV led to decline of glycerol
conversion due to the limitation of active sites as less catalyst weight was introduced. Moreover, the lowest WHSV would reduce the glycerol conversion and
hydrogen yield as more metal active sites were exposed to the intermediate species
of reaction which would favor the carbon formation and led to deterioration of catalyst (Harun et al. 2019; Pairojpiriyakul et al. 2014).
7.3.3 Effect of Molar Ratio of Carbon Dioxide-to-Glycerol
GDR is a reaction between one mole of glycerol with one mole of CO 2 to produce
syngas consists of CO and H 2 and water as shown in Eq. (7.2). From the overall
main reaction of GDR, CO 2 -to-glycerol of 1 is an ideal thermodynamic conditions
to achieve high yield of syngas. Wang et al. (2009) reported that at 727 °C of operating temperature with CO 2 -to-glycerol ratio of 1 was found as the optimum condition
to reach maximum yield of hydrogen. However, many researchers have been investigated the effect of CO 2 -to-glycerol towards the product yield (Tavanarad et al.
2018; Bulutoglu et al. 2018; Harun et al. 2019).
Bulutoglu et al. (2018) have studied the influence of CO 2 -to-glycerol ratio within
0–4 over Rh − ZrO 2 and Rh − CeO 2 catalysts at 750 °C towards the syngas product
yield. From their observation, ~96% of glycerol conversion was achieved with
presence of glycerol only with no CO 2 inlet was introduced (CO 2 -to-glycerol = 0).
Meanwhile, the glycerol conversion decreases around 30% along with the increasing CO 2 -to-glycerol ratio from 0 to 4 at constant reaction temperature (Bulutoglu
7 A Short Review on Production of Syngas via Glycerol Dry Reforming