Poplar (Populus nigra) flash pyrolysis has been performed at the IK4-Ikerlan 25 kg h(-1) pilot plant equipped with a conical spouted bed reactor. Gas, bio-oil and char yields and properties have been studied in the 425-525 degrees C range. This reactor has been proven to be especially suitable for this process as high bio-oil yields have been obtained, with the maximum being 69 wt.% at 455 degrees C. The bio-oil has been collected in two fractions: the lighter one, which accounts for 85 wt.% of the bio-oil, has a high water content and is composed mainly of acids and ketones, whereas the heavier fraction has a lower water content and is rich in phenols. These fractions are miscible, obtaining a bio-oil with a water content lower than 25 wt.% and a higher heating value in the 16-18 Mj kg(-1) range. (C) 2015 Elsevier B.V. All rights reserved.