Flour Mill By The Bay ... Ardent Mill's Automated Flour Mill Replacement Near Tampa, FL

Travel to flour mills around North America, and you’ll see a variety of innovative approaches to plant management.

But only at Ardent Mills, LLC’s brand new Port Redwing mill in

Gibsonton, FL outside of Tampa, will you see all of the plant production personnel carrying tablet computers giving them complete access to data relating to mill performance from anywhere in the facility.

It’s also the only place in North America where you’ll see oceangoing vessels deliver 1 million bushels of wheat at a time directly to a flour mill. That hasn’t happened yet since Ardent Mill’s Port Redwing mill began production in January 2022, but it will, says Plant Manager Steve Neely.

Prior to his arrival in the Tampa area two years ago, Neely worked at other Ardent Mills locations, and prior to that for Cargill and Horizon Milling, both predecessor companies.

“Before Port Redwing opened, we already had a strong presence in Tampa and a large customer base throughout central Florida,” he says.

Before breaking ground on Port Redwing in October 2019, Ardent Mills operated a 14,400-cwt.-per-day mill just outside of downtown Tampa. It had been acquired by ConAgra Milling – another predecessor to Ardent Mills – in the early 1970s. The old mill contained two production lines, an A mill that ground spring wheat and whole wheat, while the B mill ground winter wheat.

Mandatory Move

In the late-2010s, a developer, SPP Group, acquired land on Water Street, including the flour mill site, for a shopping, dining, and entertainment development.

Under agreement with Ardent Mills and the city, SPP Group assisted the miller in finding a new 10-acre site for a new mill on a peninsula extending out into Tampa Bay in suburban Gibsonton. The peninsula is known as Port Redwing and is part of the Port of Tampa Bay.

Ardent Mills constructed a milling complex including a 4.1-million-bushel slipform concrete grain elevator and a

17,500-cwt.-per-day slipform concrete, six-story flour mill.

This mill also has two units. The 12,500-cwt.-per-day A mill grinds hard red winter and hard red spring wheats and a B mill produces flour from hard, soft, and whole wheat varieties. The 150,000-square-foot mill has enough space to add a C mill as needed.

Ardent Mills decided to install Bühler mills in the structure, and the milling units have almost all Bühler equipment. “We have a strong collaborative relationship with Bühler,” Neely says.

Another previous partner on the project was Younglove Construction, L.L.C., which built the elevator and structure for the mill.

Receiving Elevator

The Port Redwing mill can receive wheat by truck, rail, and ship. Not much wheat is grown in central Florida, so there isn’t a lot of grain truck traffic. Instead, the mill mainly has a ladder-type railyard off the CSX Transportation railroad, with enough space to handle a 110-car unit train out of the Midwest or Plains.

Railcars deposit wheat into a rail receiving pit and deliver grain to the elevator through an AGI Hi Roller 40,000-bph Hi Life enclosed belt conveyor to a Warrior leg and then a set of 40,000-bph BCI top distribution drag conveyors.

The shipping berth can handle vessels one size down from the large Panamax size. Ships will send grain to the elevator via a series of up to five AGI Hi Roller 20,000-bph portable enclosed belt conveyors set up alongside the ship. Each one has a large hopper inlet that can be fed with a clamshell unloader. These conveyors feed three stationary AGI Hi Roller 20,000-bph enclosed belt conveyors running 2,000 feet to the plant.

The storage elevator consists of 12 slipform concrete, 300,000-bushel tanks that are 56 feet in diameter and 160 feet tall. Between rail and ship, the elevator can receive wheat at up to 40,000 bph. The tanks have Sioux Steel Daay paddle sweeps and Safe-Grain bin temperature detection and aeration systems.

The tanks are set up with an automated aeration system with parameters programmed by Interstates for turning fans on and off based on moisture level of the grain and ambient temperature and humidity outside.

The tank hoppers empty onto four AGI Hi Roller 10,000-bph enclosed belt conveyors in above-ground tunnels.

Grain is transported via 10,000-bph conveyors and legs to a set of twelve 42,000 bushel slipform concrete blending bins. They are 22 feet in diameter and 145 feet tall.

Milling Operations

The slipform concrete mill has a total of 150,000 square feet of floor space and stands six stories tall for the two milling units, plus an additional three stories of wheat storage on top.

All cleaning and milling equipment is from Bühler, with a flow designed by Bühler engineers.

Wheat coming into the mill is run through a wheat heater to prevent condensation prior to entering the cleaning house.

The cleaning process starts with a Bühler Grain Classifier Vega unit, which combines aspiration and sizing steps. This is followed by scouring, another aspiration step, and impact separation.

The final step prior to tempering is for wheat to be run through at least one of three Bühler Sortex color sorters. These are outfitted with cameras that can sense red, green, and blue wavelengths of light to be able to pick up even the most subtle variations of color.

Wheat then goes into one of 10 tempering bins. Temper time can vary from a few hours for soft wheat up to more than 24 hours for some hard red spring wheat.

After tempering, wheat goes through another scouring/aspiration step before being sent to first break.

The 12,500-cwt.-per-day A mill

includes 25 Bühler Arrius® integrated grinding systems (rollstands), seven double-high and 18 single-high; six eight-section sifters; eight purifiers; 25 impact detachers; 11 bran dusters; and five bran reducers.

The 5,000-cwt.-per-day B mill includes 11 Bühler Arrius grinding systems, three double-high and eight single-high three sifters, two eight-section and one four-section; three purifiers; 14 impact detachers; six bran dusters; and six bran reducers.

The Arrius MRRA is Bühler’s first fully integrated grinding system. The Arrius features a pre-stressed and backlash-free roll pack. This creates a stable grinding process and optimizes energy transfer into the product – the Arrius reportedly uses up to 10% less energy than conventional roller mills. The belt-free design and integrated control panel allows for fast installation in a form Bühler calls “plug and play.”

Performance Monitoring

The Arrius system also includes an integrated web server that allows the grinding systems’s performance to be monitored by a variety of computer devices, including smartphones, tablets, and personal computers.

This, in turn, opens the door for a much more extensive automation system. Automation at Port Redwing includes some elements of Bühler’s “Mill E3” concept, which the manufacturer has been developing and testing at a Whitworth Bros. Ltd. flour mill in the United Kingdom. (For more on Mill E3, see the First Quarter 2022 issue of Milling Journal.)

The portion of Mill E3 adapted to the Port Redwing mill includes not only the performance monitoring available from the Arrius rollstands but also data from a series of NIR (near-infrared) analyzers placed throughout the mill flow in the two milling units.

These analyzers continuously monitor flour quality factors such as moisture, protein, and ash, which is combined with data from Arrius at every step of the milling process.

Production team members working inside the mill all carry tablet computers, which allow them to see this data in real time wherever they are in the building. The entire building is a Wi-Fi hot spot, enabling them to do this.

“If there’s a problem anywhere in the building, our crew can see it on their tablets and respond to it in real time,” Neely says. “It’s like having all of your tools right where you are.”

Delivery to the Customer

Port Redwing’s output is roughly 75% bulk and 25% bagged.

Bagged flour is loaded into 25- and 50-pound bags on a pair of high-speed Behn+Bates packaging systems at up to 26 bags per minute.

Port Redwing operates two batch-mixing loadout systems for all bulk loads to deliver precision blending and to ensure consistency to the customer. A total of six drop bins with fluidizing bin bottoms and automated drop socks are capable of loading a bulk truck in fewer than five minutes. The mill operates two bulk trucks.

Ed Zdrojewski, senior editor