Process for quenching product gas of slagging coal gasifier

A process for quenching of the partial combustion product gas of a slagging coal gasifier containing suspended molten, sticky slag particles to a temperature at which the slag particles are no longer sticky which comprises:

• a. passing the hot partial combustion product gas into a tubular quench zone;
• b. introducing into said quench zone a cooling gas which is injected radially to effect admixture with, and direct quenching of, the hot product gas and
• c. introducing circumferentially into said quench zone, at its inlet end, a particle-free shielding gas thereby forming an annular layer between the product gas and the quench zone walls, said annular layer being maintained for a sufficient distance along the axis of the quench zone to prevent contact between the quench zone walls and the hot product gas prior to quenching.