PAM (polyacrylamide) granules are widely used in municipal water treatment, industrial wastewater purification, oilfield drilling, papermaking, textile, and coal washing. Because PAM particles can easily absorb moisture and become sticky, their handling requires a well-designed pneumatic conveying system. A reliable PAM particle pneumatic conveying solution moves granular material safely through enclosed pipelines, prevents contamination, reduces dust emissions, and preserves product quality.

PAM, or polyacrylamide, is a high-molecular-weight polymer supplied as white granules or microbeads. It is an essential agent for flocculation, sedimentation, sludge dewatering, enhanced oil recovery, and paper retention. However, PAM granules are hygroscopic, electrostatic, and often formulated with additives that make them cohesive. If handled by open conveyor belts or manual flow, they can absorb moisture, cake, bridge, or degrade. Pneumatic conveying offers a completely enclosed, clean, and flexible method to transfer PAM granules from a bag-emptying station, bulk bag unloader, or silo to process tanks, mixers, and storage equipment.

There are two main pneumatic conveying approaches for PAM granules: dilute phase and dense phase. In dilute phase conveying, air velocity is high, usually 15-30 m/s, and the granules are suspended in an air stream. This method suits short-distance transfer and moderate conveying capacity. Because the velocity is higher, impact and attrition can occur, so the pipeline should be smooth and the components wear-resistant. Dense phase conveying uses lower velocity, often below 10 m/s, and transports pellets as a moving bed or plug flow. This gentle method minimizes particle breakage, reduces dust, and is ideal for fragile PAM granules. Dense phase is often recommended when granules need to remain intact and when the distance is longer.

Positive pressure systems push material from a blower into the pipeline through a rotary valve or screw feeder, while negative pressure systems use a vacuum pump to draw material from one or more pick-up points. For PAM granules, positive pressure dilute or dense phase systems are widely used for single-point, long-distance transfer. Negative pressure systems are convenient for unloading from bags or drums and for multiple feed points. A hybrid system can combine a vacuum receiver with a positive-pressure pressure vessel to deliver PAM granules at controlled rates. The choice depends on conveying distance, capacity, available headroom, and the physical properties of the granules.

A complete PAM particle conveying system consists of several carefully selected components. A rotary airlock valve feeds the granules into the conveying line while preventing air loss. A roots blower or screw compressor provides the conveying air. A filter receiver or cyclone separator is used at the discharge end to separate air and material. A bag filter or cartridge filter cleans the exhaust air and prevents PAM dust from escaping. An automatic control panel monitors pressure, temperature, valve position, and motor current. Optional moisture-proof hoppers, dehumidifiers, pneumatic diverting valves, and level sensors can be added to improve performance.

PAM granule conveying systems must address moisture and caking. The conveying air should be dry and oil-free. A desiccant air dryer or at least a coalescing filter should be installed after the compressor. The pipeline should be free of sharp bends and dead zones where material can accumulate. Long-radius elbows or short-radius elbows with replaceable wear backs are recommended. The interior of the pipeline should be smooth, and flanges should be aligned closely to avoid ledges. The storage hopper should be equipped with a dehumidifier or a lined surface to reduce adhesion. For easy cleaning, quick-open flanges and handholes can be provided at critical locations.