Clean Nozzles Optimise Production by Reducing Spray Dryer Hazards

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GEA Process Engineering A/S

The use of spray dryers has increased significantly over the last ten years in the food industry, especially in the dairy sector. But spray dryers present explosion and fire hazards, especially in 24/7 operations. The risk of explosion is mainly caused by formation of deposits on the spray nozzles in the spray dryer; when exposed to continuous levels of heat in the system, they are prone to ignition. Once ignition occurs, the propagation of the flame through the suspended powder dust can cause a rapid rise in pressure; the result can be a fire or a dust explosion.

At the same time, feed lines require throughout daily cleaning to prevent undesired bacterial growth and the risk of producing off-spec products. This requires a cleaning system that can efficiently purge and atomise the product remaining in the feed lines into the spray dryer to prevent loss of valuable concentrated feed product.

Risk of remaining feed products diminished
When cleaning the feed system, GEA’s patented Clean Purge system ensures that any remaining feed product is pushed out through the spray nozzles and atomised just as efficiently as under normal production, and that the spray nozzles are completely empty after cleaning. This can significantly reduce the well-known cause of fires and explosions in food and dairy spray dryers. By purging any feed residue from nozzles before they are removed for cleaning, GEA Clean Purge prevents droplets of feed from falling into the dryer where they can catch fire.

Significant operational savings
GEA Clean Purge is the only fully patented solution that significantly reduces safety risks, representing an important step forward for food and dairy powder production. Besides addressing the primary cause of fire and explosions in food and dairy spray dryers, the Clean Purge system from GEA offers significant and valuable product and operational savings.

The savings will be obtained by reduced cleaning frequency, reduced water, energy and chemical consumption, lower costs for wastewater disposal and higher overall equipment efficiency. Simply by eliminating feed remaining in the system before cleaning cycles, a typical plant that operates with a 24/7 concept and produces 5-7 tons of powder per hour, would be able to increase the annual yield by approximately 40-60 tons at daily operations.