Coal gasification apparatus wherein a combustible mixture is formed and burned, comprising a combustion supporting gas such as oxygen, and a coal slurry. The hot products of combustion which issue from the burner, are directed into the reaction chamber of a synthesis gas generator. To avoid deposition of slag and ash particles along the hot, exposed face of the burner, a dynamic fluid blanket or barrier is directed transversely of the burner face. The reaction chamber includes an elongated port in which the burner is registered. To shield the burner, a manifold depends from the reaction chamber wall adjacent to the burner face and projects a stream of coolant fluid transversely of the face.