Paraformaldehyde (Spray Dryer Process) Plant

The PF process is that formaldehyde concentration is improved to 85% via level two condensation, then pumped into spray dryer. The high concentrated formaldehyde is sprayed via nozzle, condensed to grainy formaldehyde solid, then dried through fluidized bed dryer, finally 92% paraformaldehyde comes out. This process is with continuity and short prilling time for high concentrated formaldehyde, which forms into short linear formaldehyde molecular chain, thus with good product solubility.

Paraformaldehyde, produced via spray drying, utilizes high-temperature air to rapidly evaporate moisture, yielding uniformly granular powder ideal for large-scale industrial applications. Key uses include synthetic resins (e.g., urea-formaldehyde resins), pesticide granules (glyphosate carriers), construction additives (gypsum board enhancers), industrial cleaners (slow-release formaldehyde biocides), and foundry sand binders, balancing efficient production with easy dispersion.

Key Applications:

Pesticide Granules: Spray-dried paraformaldehyde powder serves as a carrier for herbicides (e.g., glyphosate), ensuring uniform granule distribution and field dispersion.
Gypsum Board Enhancers: Added to gypsum boards to improve moisture resistance and mechanical strength via slow formaldehyde release.
Industrial Cleaners: Powdered slow-release biocides for microbial control in pipeline or equipment cleaning.
Foundry Sand Binders: Acts as a thermosetting binder for rapid molding and high-temperature stability of casting sand.
Synthetic Resin Feedstock: Uniform powder enables continuous urea-formaldehyde resin production with enhanced reaction efficiency.
Rubber Vulcanization Accelerators: Provides controlled formaldehyde release to aid sulfur crosslinking in rubber processing.

Introduction

Too high temperature will make formaldehyde having Connie’s reaction. So normal formaldehyde condensation adopts vacuum dehydrating.

Dilute formaldehyde recycling process: adopting the lates SL-TECH technology on methylal reactive distillation.

Drying system: adopting insert gas circulating drying and negative pressure control, dealing the problem of bad environment in workshop and system safety risks.

Technical Features

The spraying prilling process can control the formaldehyde content between 92~96%, loose and good solubility, short depolymerization time. The new type PF plant brought out by SL-TECH is very popular, the features are as follows:

The advanced concentration and dryer process is adopted, with good quality and low expense, mature and reliable technology. The plant is completely nationally made, it can compare with the biggest PF producer in the world.

In the technology, formaldehyde condensation system research, the spraying tower design, the nozzle design and catalyst choosing are attached high importance to.

The dilute formaldehyde recycling of paraformaldehyde condensation system makes methylal, further becomes methylal solution with more additional value, the continuous and circular usage is the biggest characteristic of the plant energy saving, At the same time, it requires low consumption, comparing to the same career at home, the product is with low cost and competitiveness in the market.

Process Characteristics

High-Temperature Rapid Drying
- Hot Air Flow: Uses 100–200°C hot air to rapidly evaporate moisture from atomized droplets, achieving short drying times (seconds-level), suitable for thermally stable materials.
- Continuous Production: Features continuous atomization, drying, and collection, ideal for large-scale industrial processes.
Particle Size Control via Atomization
- High-Pressure Nozzle/Centrifugal Atomization: Liquid feedstock is dispersed into micron-sized droplets using atomizers, directly determining the particle size and uniformity of the final powder (e.g., 80–200 mesh).
Single-Step Formation
- Integrated Drying and Granulation: Converts liquid feedstock directly into dry powder, eliminating the need for additional crushing steps.
High Adaptability
- Capable of handling high-concentration, high-viscosity formaldehyde solutions, though temperature control is critical for heat-sensitive materials.

Core Advantages

High Production Efficiency
- Continuous operation enables high throughput, ideal for mass production of industrial-grade paraformaldehyde.
Excellent Powder Flowability
- Uniform, spherical particles ensure easy dispersion and downstream processing (e.g., mixing, tableting).
Process Flexibility
- Adjustable atomization parameters (pressure, speed) and air temperature allow customization of particle size and moisture content (≤2%).
Energy-Saving Potential
- Heat recovery systems reuse residual heat from exhaust air, reducing energy consumption (compared to vacuum drying).
Broad Application Compatibility
- Products are suitable for scenarios requiring rapid dissolution or uniform dispersion (e.g., pesticide granules, industrial cleaners).

Typical Application Scenarios

Industrial-Grade Paraformaldehyde: Fields requiring moderate purity but large-scale supply (e.g., synthetic resins, construction materials).
Carrier-Based Products: Scenarios needing uniform loading of active ingredients (e.g., pesticide granules, slow-release biocides).
Rapid Processing Demands: Direct use of powder in continuous reactions (e.g., urea-formaldehyde resin production).

Paraformaldehyde specification

S/N	Item	Process index	Note
1	PF content	92% w/w	Normally 92%
2	Formic acid	＜0.03%
3	Melting range	120~170℃
4	Ash content	＜100 ppm
5	Appearance	White powder
6	Methanol content	＜1 wt%
7	Free water	＜8 wt%
8	Iron content	＜2 ppm