Paraformaldehyde

1. Material Overview

Paraformaldehyde is a polymer of formaldehyde, typically with a structural length of eight to one hundred units. Long-chain Paraformaldehyde is commonly used to produce heat-resistant plastics, also known as polyoxymethylene plastic (POE, DuPont's Derlin).

Paraformaldehyde is mainly used in the production and use of herbicides, and also in the manufacture of synthetic resins (such as artificial horn products or artificial ivory) and adhesives. It is also used in the pharmaceutical industry (as the active ingredient in contraceptive creams) and for disinfection in pharmacies, clothing, and bedding. Paraformaldehyde can also be used as a fumigant, disinfectant, and insecticide.

2. Process Introduction

The drying system adopts closed-loop circulation process with gas protection. The paraformaldehyde (PA) liquid from the upstream section first is fed into spray dryer for preliminary drying to produce PA particles, and then it is fed into fluid bed dryer (FBD). During the drying process, the gas entering the FBD is effectively controlled, thus maintaining the stable fluidization state of the feedstock inside the FBD. The dried product is discharged at the overflow port of the FBD through the discharge valve.

3. Technical Advantages

1) The system adopts two-stage combined process of spray drying tower for pre-drying and closed-loop fluid bed dryer for deep drying, resulting in reasonable heat and mass transfer. matching and significantly superior drying efficiency and endpoint control accuracy compared to single-stage drying equipment.

2) The process gas achieves closed-loop circulation between the two stages, operating in an inertial, sealed environment throughout. Gas and waste heat are recycled and reused without external discharge, greatly improving nitrogen utilization and overall thermal efficiency.

3) The two stages operate continuously and in conjunction, allowing for independent segmented control of temperature, airflow, and residence time. This provides strong process adaptability, stable system operation, and a high level of automation control.

4.Technical Benefit

1) More stable product quality

Due to the two-stage precision drying process combined with a fully enclosed environment, materials are free from oxidation and overheating, resulting in high moisture uniformity and significantly improved finished product purity and yield.

2) Lower overall operating costs

Closed-loop recycling and efficient waste heat utilization significantly reduce energy and nitrogen consumption; the equipment has a simple structure and low failure rate, reducing daily maintenance and media usage costs simultaneously.

3) Environmental friendly protection

Fully enclosed operation eliminates waste gas and dust emissions, requiring no additional exhaust gas treatment equipment;

Continuous and stable operation can ensure large-scale production, reaching environmental standard without additional rectification risks.