An object of the present invention is to overcome the disadvantages of the prior art by directly contacting a non condensible gas as {HEAD ~ a feed gas} with {TAIL ~ heated water}, thereby humidifying the feed gas, while utilizing the heat possessed by the formaldehyde product gas as a heat source for heating the water 
with
An object of the present invention is to overcome the disadvantages of the prior art by directly contacting a non condensible gas as { HEAD ~ a feed gas } with { TAIL ~ heated water } , thereby humidifying the feed gas , while utilizing the heat possessed by the formaldehyde product gas as a heat source for heating the water
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH