Abstract:

In order to solve the problem of low denitrification efficiency caused by the uneven mixing of ammonia and flue gas with an F-class gas turbine horizontal arranged waste heat boiler denitrification system, numerical simulations, lab-scale model experiments and engineering tests were carried out to study the effects of the approach of ammonia injection optimization. The numerical simulation results show that with adding a guide plate, the flue gas velocity gradient at the inlet plane of the ammonia injection decreases significantly, and the flue gas velocity distribution at the inlet plane of catalyst-bed is nearly uniform. The model experiment results show that the standard deviation of flue gas velocity at the catalyst-bed inlet plane decreases to 10.7%, and the standard deviation of ammonia concentration decreases to 6.06%. It indicates that the flue gas and ammonia are mixed well, and the flue gas velocity field is uniform. The engineering test results show that with the addition of the guide plate, the NO_x concentration in the outlet plane of the catalyst-bed is uniformly distributed, all the measured NO_x concentrations are less than 30mg/Nm³, and the NO_x concentration deviation is less than 15%, indicating that this method could effectively improve the denitrification system.

Key words: gas turbine, denitrification, selective catalytic reduction(SCR), spraying ammonia grille, guide plate