Abstract: An emission control apparatus which can be used on an outdoor wood-fired boiler. Ambient air, which has a much higher concentration of available oxygen in relation to exhaust gases, is caused to be heated before being passed through catalyst-coated media along with exhaust gases, thereby improving the performance of the catalytic reaction.

Abstract: A multitube reactor for exothermic or endothermic reactions carried out in a multiplicity of tubes, which are surrounded by a liquid, at least part of which is circulated by a circulating pump, which is disposed outside the reactor structure, to flow through heating and cooling means and is the recycled to the reactor structure. The tubes and the surrounding liquid are disposed between a cylindrical inner wall and an outer wall which surrounds and is coaxial to the inner wall. The circulating pump is disposed in the liquid-free space that is surrounded by the inner wall.