Sugar as a material is sweet to the taste, but unless the proper precautions are taken when handling this ingredient, those tasked with conveying it may feel bitter about the results. With its crystalline structure and hygroscopic nature, the challenges that sugar handlers face boil down to a simple credo: “keep it dry and keep it moving.”
Sugar is an extremely common ingredient in multiple ingredient-handling industries, so many may already understand how to maintain its crystalline form effectively for their processes. Still, it’s not always taken into account that an entirely different set of requirements is needed for handling sugar in a powdered form and, more importantly, that sugar possesses explosivity characteristics to always be vigilant about.
Providing the necessary equipment to handle a hygroscopic material is arguably the biggest critical consideration for handling sugar. This material will absorb moisture with ease, so leaving it in a silo for an extended period of time will result in it becoming extremely resistant to flow. Pickaxes and physical labor may be required in this unfortunate circumstance.
Downstream, specialized equipment such as delumpers aid sugar that has clumped after being exposed to elevated temperatures or humidity. It is critical to keep sugar in a dry-air or air-conditioned state and environment for optimal flow results.
Sugar is heavier in bulk density than other materials such as flour. Each particle of sugar will weigh more than a powder and, in less space, there will be a greater quantity of it. Like salt, as sugar is placed on someone’s finger, they can physically feel the material more than when holding powders like flour. When handling sugar, this should absolutely be taken into account. Certain equipment and greater levels of energy are often required to convey heavier materials with greater bulk densities.
At AZO, we have found, unfortunately, that there are many who still don’t realize the explosive threat that sugar poses. For example, a Domino Sugar mill in South Baltimore experienced an explosion in 2007 caused by a failed bearing and ignited sugar powder that sent a "high-pressure combustion wave" through the plant's ductwork. Domino was fined by the Maryland Occupational Safety and Health Administration (MOSHA) and OSHA, and NFPA regulations were altered afterward as a result.
Broken equipment inside a steel conveyor belt caused the first explosion (that then triggered other dust-related explosions). OSHA and the U.S. Chemical Safety Board both launched investigations that found company officials knew about potential hazards for years but chose not to correct them. While strict rules about hardhats and other safety gear were enforced, employees received minimal training on how to avoid dust explosions. The very next year national headlines covered explosions in Port Wentworth, GA. Knee-high piles of highly combustible sugar dust fueled explosions at the Imperial Sugar refinery. Imperial reached a $6 million settlement with OSHA and civil cases for damages followed.
Making sure a conveying system is outfitted with explosion protection goes hand in hand with ensuring any required extra space for this protection. Extra measures often need to be taken in a facility to ensure that necessary protection can fit in the plant real estate available, such as ensuring that a vent can be ducted to the outdoors through a wall.
If you aren’t careful when handling granular sugar, your material could quickly become powdered sugar. For those actively and intentionally handling powdered sugar, specific processes and requirements are necessary to properly enable material flow. Powdered sugar should not be stored in large quantities and, if it is put into a receiver or small indoor silo, it must be kept agitated mechanically.
Even a live vibratory bottom will not be sufficient in enabling the flow of powdered sugar. AZO actually makes a specialized agitating hopper specifically for powdered sugar as an ingredient. Powdered sugar is also very difficult to filter. Powdered sugar’s fine particles find their way through normal filter media and can also accumulate and clog these filters.
A partner like AZO is made up of employees driven to discover solutions for our clients. We know these solutions influence what we can find on our own grocery store shelves. AZO provides sophisticated systems that can effectively handle sugar and help a facility:
AZO solutions are individually fit to our customer’s requirements and optimized for the most economical and flexible results. We designed our systems for handling bulk sugar to include blanketing a silo with dry air. We use both dry air and cooled-air to convey sugar. AZO can also include “VB”s (Vibratory Bin Bottoms) to silos in order to promote material flow.
To promote mass flow and to overcome bridging in the silo, we condition the airspace in the silo to help avoid or minimize the effects of moisture on sugar (caking and sticking to the silo sidewalls). In addition to the VB on the bottom of a hopper, AZO also recommends an AZO Delumper for any sugar lumps that form. Our centrifugal screeners take care of any unwanted foreign material in your process, and our TW650 Screeners do this while silos are filled from trucks or rail cars.