Kinetics of the water-gas shift reaction in supercritical water

A series of experiments for the measurement of non-catalytic water-gas shift reaction (CO + H2O --> CO2 + H-2) rate was conducted in supercritical water at temperatures of 380 to 440 degrees C and pressures of 10 to 30 MPa using a flow-type apparatus. At 380 degrees C, the reaction rate first gradually decreases to a minimum at around the critical point, and then increas with increasing water density. The results at 400 degrees C, however, indicate that the reaction rate order is zero with respect to water density. The rate constant for the water-gas shift reaction is correlated with a global reaction model, that can reproduce the experimental data of CO conversion at 380 similar to 440 degrees C and 10 similar to 30 MPa.