Paddle Dryer for Food, Starch and Agro Residue Drying

Karan Dargode — Mon, 26 Dec 2022 06:48:42 +0000

Food and agro processors produce wet by-products every day: spent grain, starch cake, rice bran, fish meal and distillery residue. They spoil quickly, smell and cost money to move. Drying turns them into stable products that can be stored, sold or used as feed.

What the food and feed industry asks of a dryer

Temperature control. Proteins, starch and fats can be damaged by too much heat.
Hygiene. Surfaces that touch the product must be easy to clean, and the material of construction matters.
Odour. Fish meal and spent grain smell strongly while drying. The vapour must be captured, not vented.
Even drying. Uneven moisture inside a batch invites mould in storage.
Sticky feed. Many of these materials turn tacky in the middle of drying.

How a paddle dryer addresses them

Heat reaches the product through jacket and shaft surfaces, so the heating medium, which may be steam, thermic fluid or hot water, never touches the food. Hot water or low-pressure steam can keep surface temperatures moderate. The machine is enclosed, so vapour goes to a condenser or scrubber and not into the plant. Slowly turning, self-cleaning paddles mix the product continuously, and a plug flow design keeps material moving from inlet to outlet without back-mixing, which helps evenness.

For food duty, AS Engineers offers stainless steel in SS304 and SS316, with surface finish options up to electropolishing, and can build vacuum versions where lower temperatures are needed.

Materials AS Engineers lists

In agriculture and animal feed: DDGS (dried distillers grains with solubles), rice bran and fish meal. In food and beverage: starch. Spent grain also appears in its food, pharma and starch group. Which of these suits a given installation depends on moisture, fat content and the quality target, so each project is checked on the actual material.

Things to settle early

Question	Why it matters
Final moisture target	Decides storage life and how far to dry
Maximum product temperature	Protects quality and nutrition
Fat or oil content	Affects stickiness and fire safety
Hygiene standard	Sets the finish, seals and documentation
Where the vapour goes	Decides the condenser and scrubber design
Throughput and operating hours	Sets the size

What a food line looks like

A typical line has a feed hopper and screw feeder, the paddle dryer, a condenser or scrubber for the vapour, a conveyor to take the dried product away, and optional bagging. A heat source such as a steam boiler, thermic fluid heater or hot water generator supplies the heating medium.

Test before you buy

Food products are sensitive to how they are dried, so a trial pays for itself. 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.

More from AS Engineers

See the full range on paddle dryers for the food industry at theasengineers.com.

For wider sludge background, read the industrial sludge management guide on sludgedryer.in, AS Engineers’ sludge drying resource.

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Paddle Dryer for the Food Processing Industry | AS Engineers