Abstract: A self-cleaning liner for high pressure boilers. The self-cleaning liner comprising a tubular liner and a sprayhead assembly. To minimize thermal shock, the sprayhead assembly protrudes into a cavity created by the formation of a bump in the tubular liner, shielding the sprayhead assembly from high temperatures. The sprayhead assembly may also incorporate a thermal sleeve to decrease thermal shock caused by the temperature difference between the sprayhead assembly and the cleaning medium.

Abstract: A steam generating heat exchanger (2) for cooling a high pressure, hot gas laden with molten ash particles comprising an inverted U-shaped pressure containment structure (4,6,8) having various heat exchange means disposed therein. The heat exchanger is formed of a first vertically elongated cylindrical pressure containment vessel (4) housing a radiant cooling chamber (12) therein, a second vertically elongated cylindrical pressure containment vessel (6) housing a convective cooling chamber (30) therein, and a pressure containment pipe (8) connecting the second pressure containment vessel (6) to the first pressure containment vessel (4) and housing therein a water-cooled duct (26) connecting the gas outlet of the radiant cooling chamber (12) disposed within the first pressure containment vessel (4) to the gas inlet of the convective cooling chamber (30) disposed within the second pressure containment vessel (6).