A double-input-multi-output linearized system is developed using the state-space method for dynamic analysis of methanation process of coke oven gas. The stability of reactor alone and reactor with feed-effluent heat exchanger is compared through the dominant poles of the systemtransfer functions.With single or double disturbance of temperature and COconcentration at the reactor inlet

typical dynamic behavior in the reactor

including fast concentration response

slow temperature response and inverse response

is revealed for further understanding of the counteraction and synergy effects caused by simultaneous variation of concentration and temperature. Analysis results showthat the stability of the reactor loop ismore sensitive than that of reactor alone due to the positive heat feedback. Remarkably

with the decrease of heat exchange efficiency

the reactor system may display limit cycle behavior for a pair of complex conjugate poles across the imaginary axis.