This paper presents the energy performances of a pneumatic installation designed to improve the homogenization degree of the mixture consisting in recirculated flue gas and primary air used in pulverized coal combustion. The installation consists in a series arrangement of a centrifugal fan and a side channels blower. The experimental setup is intended to equip the burner of a 2.5 MWh pilot boiler, where the influence of the mixture parameters on the reduction in NOx emissions is studied. The performance curves of the centrifugal fan and those of the side channels blower were obtained experimentally. Based on them, the performance curves of the series arrangement were obtained analytically, in order to assess the variation of pressure depending on the flow rate required by the burner. Of a particular interest was the degree in which the usage of the side channels blower could eliminate the risk of surge typical for centrifugal fans operating at low discharges.
