The invention relates to the field of
formaldehyde preparation, in particular to a
formaldehyde rectifying
tower. The
formaldehyde rectifying
tower comprises a
fixed frame, a heating mechanism, a rectifying mechanism, a feeding mechanism, a condenser
pipe, a cooling mechanism, a connecting mechanism and a collecting mechanism; gas is pre-cooled and liquefied inside the condenser
pipe into a
formaldehyde solution to enter the cooling mechanism; the
formaldehyde solution tortuously moves inside the cooling mechanism, and the re-cooled
formaldehyde solution penetrates through the connecting mechanism to enter the collecting mechanism; at a
room temperature, formaldehyde in the formaldehyde solution inside the collecting mechanism evaporates, and the
gaseous formaldehyde is in contact with low-temperature formaldehyde solution to be liquefied into the low-temperature formaldehyde solution, so that the
evaporation speed of the formaldehyde in the collecting mechanism is reduced; in the rectifying process, part of the low-temperature formaldehyde solution slides inside the connecting mechanism to enter the rectifying mechanism;
reflux fluid inside the rectifying mechanism is at a low temperature, and the
boiling point of the formaldehyde is low, so that the formaldehyde inside the
reflux fluid evaporates into the condenser
pipe, and the content of the
gaseous formaldehyde is increased.