Environmental Engineering Reference
In-Depth Information
Gas Phase
CH 4 + H 2 O
CH 4 + H 2 O = CO + 3H 2
CO + H 2 O = CO 2 + H 2
Fuel Cell Grade
Admixture of CO 2
Chemisorbent + SMR Catalyst
Gas Phase
CO 2
Super Heated
H 2 O + CO 2
Admixture of CO 2
Chemisorbent + SMR Catalyst
Basic Principles of TSSER - SMR Concept
FIGURE 2.1 Schematic of the thermal swing sorption-enhanced reaction (TSSER)-steam-methane
reforming (SMR) concept. Source : Reproduced with permission of Beaver et al. [2].
In a recent study, a new concept based on sorption-enhanced reaction
(SER) for steam-methane reforming (SMR) was demonstrated to directly
produce fuel-cell grade H 2 (∼10 ppm CO) with very high CH 4 to H 2 conver-
sion efficiency (>99%) using an admixture of a commercial SMR catalyst
and a CO 2 chemisorbent, K 2 CO 3 promoted hydrotalcite [2]. The reaction was
carried out at a much lower temperature (520-590°C) than the conventional
reaction temperature of 700-900°C without sacrificing the reactor perfor-
mance. It also eliminates the subsequent H 2 purification step by a conven-
tional PSA process. Figure 2.1 shows a schematic of the thermal swing
sorption-enhanced reaction (TSSER)-steaming methane reforming (SMR)
concept. The overall outcomes are attributed to four related factors: (a) favor-
able thermodynamic equilibrium of the highly endothermic SMR reaction at
the higher reaction temperature, (b) faster kinetics of SMR reaction at higher
temperatures, (c) favorable removal of CO 2 from the reaction zone at lower
temperatures, and (d) higher cyclic working capacity for CO 2 chemisorption
at higher temperature.
Search WWH ::

Custom Search