Angewandte Chemie International Edition
10.1002/anie.201903000
COMMUNICATION
temperature can tune the lighter C
2
or heavier aromatic selectiv it y,
(Tables S5 and S6). These results, in combination w ith the lo w
for the targeted processesand reactor operation. On the basis of
our reactor configuration and coke formation rate, the time
costs of CH
4
feedstock and reactor material, as w ell as simple
reactor manufacturing process, demonstrate that DNMC in a
required to fill up the reactor by coking is estimated to vary from catalytic w all reactor is an economically feasible and
9
8 hours to infinite amount of time (Table S2), which is potentially
transformative technology forshifting the petrochemicalsector to
naturalgas feedstockin industry.
compatible w ith the industrialpractice.
In summary, a catalytic w all reactor made of a quartz tube
and Fe/SiO catalyst was created for the first time for DNMC. The
2
performance of the catalytic w all reactor w as studied under a
range of temperatures in combination in combination w it h
different feed gas flow rates. The obtained performance resu lt s
CH4 conversion (%)
0
10
20
30
40
50
60
35
1
1
1
40
20
00
30
25
20
15
10
5
formbasis for optimizing reaction conditions tow ardslighter C
2
or
heavier aromatic products fromCH feedstock. The integration of
4
catalyst onto reactor w all eliminates catalyst packing and
discharging steps that occur in the fixed-bed reactor. Coke was
formed in the catalytic w all reactor, and its yield varied w ith the
operating conditions, but did not deteriorate the DNMC. The coke
formation could enable an autothermal operation of DNMC. The
process simulation demonstrates a six-fold reduction in supplied
energy costs from the autothermal process w ith integrated
endothermic DNMC and exothermic coke combustion on oppos it e
sides of reactor, relative to a conventional system. The high
carbon and thermal efficiencies, low cost in reactor materials and
simple reactor manufacturing process are concurrently realized,
indicating the great technoeconomic process viability of the
DNMC technology.
8
6
4
2
0
0
0
0
0
Autothermal
operation
0
60
0
10
20
30
40
50
-
1
Heat supplied for DNMC (kJ mol
Fig. 4. Energy input for DNMC and outputby coke combustion atcorrespond in g
CH conversion and coke yield. The dashed line represents the energy input
and output balanced from both reactions. The shaded circle indicates the
feasible operation windowof DNMC autothermally in the reactor.
)
4
ExperimentalSection
The catalytic wall reactor was fabricated by heating a quartz tube
packed with the Fe/SiO catalyst to ~ 1973 K to fuse catalyst onto reactor
2
wall. After discharging the non-fused catalyst, the reactor with a flow
We carried out the energy balance analysis (Fig. 4), based
on standard heat of reaction from DNMC and coke combustion,
respectively, to explore the techno feasibility of autothermal
catalytic w all reactor. When CH conversion is < 20%, the coke
4
yield is < 3%. The heat supply for enabling DNMC reaction is
higher than heat release from combustion of coke formed in
channel and catalyst on reactor wall was prepared. The catalyst was
[
12]
synthesized following our previous report . The materials and methods,
DNMC reaction tests, DNMC reaction result analysis, energy balance
analysis and process simulation of the catalytic wall reactor were
described in details in the Supporting Information.
4
DNMC. Oppositely, w hen CH conversion is >40% and the coke
yield is > 15%, the heat release from coke combustion is higher
than heat supply for DNMC. The energy balance betw een two
Acknowledgements
reactions can be achieved w hen DNMC is run at ~33.9% CH
conversion with 25.4% C2+ yield. A recent agreement framework
4
This research is supported by the United States National Science
Foundation (NSF-CBET 1642405 and 1351384). The authors
thank for the Energy Innovation Seed Grant from the Maryland
[
11]
analysis for DNMC by Maravelias et al.
suggests that the
economically feasible DNMC is achievable at >25% CH
4
conversion, <20% coke formation and low catalyst cost. The
DNMC in our catalytic w allreactor sufficientlymeet these targets.
The process simulation using Aspen Plus too ls was
performed to evaluate the practical implications of the catalytic
w allreactor. Fig. S8(a) presents the flowsheet forDNMC. A heat
exchanger w as incorporated to utilize heat released from coke
combustion to raise the feed stream to reaction temperature,
mimicking the autothermalprocess. The reactorconfiguration and
operation are demonstrated conceptually in Fig. S8(b). The
Aspen Plus Utilities Object Manager and Economic Solver
provided estimates for externally-supplied heating and cooling
duties and costs (Tables S3 and S4). These calculations
demonstrate a six-fold reduction in supplied energy costs fromthe
autothermal process relative to a conventional system. The
DNMC reaction produces multiple industrially-valuable chemicals
and fuels – hydrogen, ethylene, benzene and naphthalene –
w hose production rates are converted into retrievable prices
2
Energy Innovation Institute (MEI ).
Keywords:non-oxidativemethane conversion • catalytic wall
reactor • iron/silica catalyst • naturalgas • process simulation
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