Dynamic analysis on methanation reactor using a double-input–multi-output linearized model

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 system transfer functions. With single or double disturbance of temperature and CO concentration 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 show that the stability of the reactor loop is more 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.

The stability of the methanation reactor with feed-effluent heat exchanger is more sensitive than that of reactor alone. Remarkably, with the decrease of the heat exchange efficiency, temperature and concentration oscillations have been confirmed because of the presence of inverse temperature response through the reactor combined with the positive feedback caused by the feed-effluent heat exchanger.Figure optionsDownload as PowerPoint slide