Paraformaldehyde Plant

Paraformaldehyde is a product of the dehydration polycondensation reaction of formaldehyde solution, also called dimethoxymethane. There are mainly two types: low polymerization degree paraformaldehyde (degree of polymerization is 2-8), and paraformaldehyde (degree of polymerization is 8-100).

Helipont provides the necessary technologies for both paraformaldehyde solutions, including the processing plan, special equipment and catalyst.

Production Process

Firstly, increase the formaldehyde concentration from 37% to 65% through concentrated dehydration, then put it into rake dryers for further dehydration, until when the paraformaldehyde become a solid powder. The entire dehydration process is operated under negative pressure. The evaporating condensate containing 10-15% formaldehyde will return to the formaldehyde section and can be used to produce methylal, urotropine or mixed to 37% formaldehyde for sale. It is a batch form operation. Each batch feed for rake dryers is around 4-5m³, drying time is 4-6 hours. The production cycle is long, while the production capacity is low, and the product is in the form of powder mixed block.

Formaldehyde concentration is increased to 80% after second-efficiency condensation under vacuum, and then pumped into the spraying cooling tower. The concentrated formaldehyde solution is sprayed through the nozzle and condensed into a granular paraformaldehyde solid. This process is consequent, the time needed is short, and the product has good solubility because of shorter formed formaldehyde chain.

The production capacity of vacuum drying process and spray drying process is similar, while vacuum drying process needs less investment and spray drying process can produce paraformaldehyde with higher quality.