Calcined waste seashell powder from cockles and mussels was used as the pretreatment materials for kraft lignin (KL), and their impacts on the pyrolysis behavior of KL were examined using a laboratory-scale fixed bed reactor and thermogravimetric analysis. The highest intensity of the CaO peak was observed on the XRD patterns of the seashell obtained from the calcination of mussel shells at 800 degrees C (M8). Char foaming was not detected when the water treated KL/seashell were pyrolyzed at 500 degrees C. In contrast, severe char foaming and agglomeration were observed when KL alone and a physical mixture of M8 and KL (KL/M8-mix) were pyrolyzed at the same temperature. The pyrolysis of water-treated KL/M8 (KL/M8/water) also produced much higher quality oil than those of KL alone or the KL/M8 mixture, showing higher selectivity to light phenols and aromatics. The decomposition temperature of KL was also decreased using M8 with water due to the catalytic effect of calcium oxide. (C) 2018 Elsevier Ltd. All rights reserved.