In the present study, the improvement of the CO2 methanation catalytic reactor in terms of energy consumption and CO2 conversion is done. In this respect, for the first time, modelling of the annular reactor is done with the goal of integrating reaction heat to preheat the feed through the inner pipe of this reactor. In the next stage the optimization problem for both reactors is defined with the goal of maximizing conversion of CO2 by optimizing the coolant and the reactor inlet temperatures. In the annular reactor in comparison with tubular reactor, conversion rate is about 5 % higher for constant cooling temperature case at Fischer operating conditions and about 26 % higher for constant cooling temperature case at optimal conditions. Compared to the tubular reactor, the annular reactor produces 8.9 % less overall heat with wider operating conditions (around 5 %). The annular reactor uses less energy and lower inlet fresh feed temperature than the tubular reactor because of the integration of reaction heat. It outperforms the conventional reactor.

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