R&D on Hydrogen Production by Autothermal Reforming

3.4 Investigation of Hydrocarbon Constituents in Fuel and of Autothermal Reforming
Characteristics
3.4.1 Experiment Method
A fixed-bed, flow-type micro reactor was used for reactions. The hydrocarbon compounds
shown in Table 3.4.1 were used as raw material, together with standard ATR catalyst A. So as
to compare the autothermal reforming reaction characteristics among each hydrocarbon, the
most ideal reaction temperature was one at which side reactions such as combustion or
decomposition could be suppressed as much as possible. Representative of each hydrocarbon,
deep desulfurized kerosene and normal hexane were taken as raw materials. Reaction was
initiated under the same conditions as for autothermal reforming reaction, using a micro-reactor
without catalyst, and the presence of side reactions in the reactor was confirmed. As shown in
Figure 3.4.1, because the C2-C4 hydrocarbon selection rate is zero at 600°C or below, it was
confirmed that no side reactions take place inside the reactor. Consequently, autothermal
reforming reaction was implemented at 600°C, where there would be no side reactions. Taking
the carbon mol flow volume included in the raw material hydrocarbons as standard, the rate was
0.71 mol/hr-C. O2/C and S/C were determined in accordance with Section 3.1.2. Reforming
reactivity was evaluated using a virtual speed constant k (CO + CO2) covering CO + CO2
production, determined on the assumption of a primary reaction and CO + CO2 selection rate
that correlates with the hydrogen selection rate targeted.
Table 3.4.1: Model Hydrocarbon Compounds Equivalent to Naphtha -
Kerosene Fractions Used
Hydrocarbon
count
n-P i-P O N A
LN 6 n-hexane 2,2
dimethylbutane
1-hexane cyclohexane benzene
HN 8 n-octane 2,2,4-trimethylp 1-octane ethylcyclohexane m-xylene
entane
ethylbenzene
KERO 10 n-decane n-butylcyclohexane diethylbenzene
Other n-dodecane,
n-hexadecane
C2-C4 selection rate (%)
10
Desulfurized kerosene
Reaction temperature (°C)
(Reaction conditions: O2/C = 0.45, S/C heat balance conditions, LHSV = 1.0 to 1.6)
Figure 3.4.1: Temperature Dependency vs Side Reaction in Reactor
1,2,4-trimethylbenzene