Pyrolysis and Combustion Behavior of Pinewood after the Addition of Flame Retardants

To investigate the effects of flame retardants on pinewood combustion, a comprehensive analytical method has been devised based on a full description of the pyrolysis process. With the addition of ammonium polyphosphate (APP), ammonium dihydrogen phosphate (NH4H2PO4), and boric acid (H3BO3), the total amount of cellulose/hemicellulose decomposition products increased by 27.9, 63.1, and 14.2 %, respectively, and the yield of lignin-derived products decreased by 22.8, 57.7, and 13.2 %, respectively. Because of the easiest release of phosphoric acid, NH4H2PO4 had the most obvious impact on destruction of the char structure by volatiles released in the pyrolysis process, resulting in the highest peak heat release rate of 273.46 kW/m(2) at a heat flux of 50 kW/m(2). The addition of APP induced similar changes in the pyrolysis products, but it showed the best fire-resistance properties because of its lower surface temperature and less destruction of the char layer by volatiles. The effect of H3BO3 was weakest.