A method of direct heat removal resulting from the phase change of n-tetradecane was used to intensify the heat transfer during hydrate formation. The growth rates of methane hydrate in aqueous slurries containing 25-45 wt % of solid n-tetradecane were investigated at pressures between 4.70 and 6.46 MPa (gauge) and near the fusion point of solid n-tetradecane. Methane hydrate growth started at a practically constant rate, which became variable after a sudden increase. Two rate laws were established to correlate with the experimental data for the constant and variable rate stages. The methane hydrate growth rates achieved with solid n-tetradecane were significantly enhanced compared with those obtained under indirect heat removal. (c) 2015 American Institute of Chemical Engineers AIChE J, 61: 3441-3450, 2015