Pharmaceutical plants dry a small range of materials under tight conditions. An API intermediate may be sensitive to heat. A calcium carbonate or sodium carbonate cake may be easy to dry but must stay clean. Solvent often leaves with the water, and it has to be handled safely. These conditions shape what a paddle dryer needs to offer.
What pharma duty requires
- Product protection. No contamination from the dryer, no cross-contact between batches.
- Temperature control. Many intermediates degrade above a set temperature.
- Solvent handling. Solvent vapour must be condensed, recovered or scrubbed, and kept away from ignition sources.
- Containment. An enclosed system limits dust and exposure.
- Cleaning. Surfaces must be smooth and accessible so the machine can be cleaned between products.
How a paddle dryer fits
An indirect paddle dryer heats the product through its jacket and hollow shafts, so the heating medium stays separate. Several features matter here:
- Vacuum operation. A vacuum paddle dryer lowers the boiling point, so material dries at a lower temperature. See our vacuum paddle dryer guide.
- Purged, closed design. The machine can be purged and closed, and the vapour sent to a condenser and solvent tank, as AS Engineers describes in its solvent recovery option.
- Materials of construction. SS304, SS316, duplex steel and other alloys, with finishes from buffing to electropolishing.
- Self-cleaning paddles. Intermeshing paddles without metal-to-metal contact reduce build-up and wear.
- Configurations. Standard, dual zone and vacuum dryers, so the machine can be matched to the material.
Materials AS Engineers lists
For pharmaceuticals and healthcare, AS Engineers lists calcium carbonate and sodium carbonate. In its food, pharma and starch group it also lists API intermediates and spent grain. Whether a specific API intermediate suits a paddle dryer depends on its heat sensitivity, hazard class and the quality rules of your plant.
What a project needs to define
| Item | Why |
|---|---|
| Material and hazard data | Sets the safety and containment design |
| Maximum product temperature | Decides vacuum, heating medium and wall temperature |
| Solvent type and quantity | Sets condenser, tank and ventilation |
| Surface finish and documentation needs | Drives material and fabrication choices |
| Batch or continuous operation | Affects size and controls |
| Cleaning method | Affects access and internal design |
Any quality documentation your plant requires should be agreed at the start of the project, not added at the end.
Test on your own material
A trial shows how the material dries, how it behaves in the sticky range and how much solvent comes off. AS Engineers runs pilot trials on a 25 kg/hr paddle dryer, at its works or at your site, for a nominal fee that is waived on order. Request a pilot trial.
Related guides: dual zone paddle dryer, filter cake dryer and paddle dryer selection criteria.
Related reading
- Sludge dryer manufacturer
- Materials we dry
- Paddle Dryer for Textile Sludge and ETP Cake
- Paddle Dryer for Chemical Wet Cake and Sludge
- Sludge Dewatering vs Sludge Drying Guide
- Industries we serve
More from AS Engineers
See the full range on paddle dryers for the chemical industry at theasengineers.com.
For wider sludge background, read the industrial sludge management guide on sludgedryer.in, AS Engineers’ sludge drying resource.
- B.E. Mechanical · GTU (2018)
- PGDBA, Operations · Symbiosis
- With AS Engineers since 2019
- Writes on paddle dryers, sludge drying & blowers
Karan Dargode leads operations and environmental health & safety at AS Engineers, an Ahmedabad-based manufacturer with over 25 years of experience in centrifugal blowers, industrial fans, paddle dryers, sludge dryers, and air pollution control equipment. He joined AS Engineers in July 2019 and has spent over six years building operational systems that support the company's engineering and manufacturing work.
