Polygonal heat exchange chamber including a tapered portion lined with water tube panels and method of lining a tapered portion of a polygonal heat exchange chamber with such panels

A vertical polygonal heat exchange chamber, comprising:

• an upper opening;
• a lower opening;
• and
• an enclosure formed between the upper and lower openings, the enclosure including (i) a first portion having a number of vertically-extending sides equal to two times N, where N is an integer greater than two, and (ii) a tapered second portion, contiguous with the first portion, that narrows in a direction leading away from the first portion, the second portion being lined with N first water tube panels arranged adjacent to and alternately with N second water tube panels, each of the first and second water tube panels being angled inwardly from the widest part of the second portion toward the interior of the enclosure, wherein each of the first water tube panels is angled inwardly to a greater degree than each of the second water tube panels.