D-Mill Open for Business

King Milling’s latest milling unit processes hard wheat at 8,000 cwts. per day

“State-of-the-Art” D-mill

Jim Doyle has been very pleased with the performance of the new mill since it began operating in late 2023. “It’s actually exceeded our expectations a bit.”

The mill, which Doyle calls “state-of-the-art,” uses Rockwell’s IntelliCENTER smart MCC supplied by Kice Automation. (King Milling already uses Kice for its B- and C-mills.)

Screens in the D-mill control room display the statuses of all equipment and subsystems involved in the milling process. Kice Automation’s SmartMills web-based platform was implemented to facilitate recipe management and enable operators to create and monitor production jobs effectively.

“We don’t run the D-mill as a lights-out facility,” he adds, “but we certainly could with this technology.”

Another innovative feature of the mill is its air make-up system. Outgoing process heat passes through a heat exchanger before being exhausted, explains Doyle. The captured heat reduced the boiler requirement of the D-mill by half.

Mill Flow

Wheat deliveries for the D-mill come by rail from producers in hard-wheat-growing states such as North Dakota, South Dakota, Nebraska, and Kansas.

Wheat to be milled is transferred from storage to eight raw wheat bins with three center bin spaces and six temper bins. All cleaning and milling equipment is from Bühler.

Wheat coming into the mill is run through a Bühler Rois flow balancer that doses a specific stream/weight of wheat. Next, wheat is weighed and sent through a drum sieve.

A wheat heater is used to prevent condensation prior to cleaning. Moisture can be troublesome in Michigan’s humid climate, says Doyle, so Todd & Sargent applied a Dryvit exterior insulative concrete coating to help control the climate inside the mill.

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, destoning, and impact separation.

Prior to tempering, wheat is run through a Bühler Sortex H7 color sorter that is outfitted with cameras to sense colored wavelengths of light to discern subtle variations in the wheat.

Wheat then goes into tempering bins for an average of 24 hours. After tempering, wheat is sent through Bühler Antares MDDR rollstands, sifters, purifiers, impact detachers, bran dusters, and a vibro-duster. The Antares MDDR rollstands are designed with entirely stainless steel interiors for sanitation purposes. Insulation and integrated ventilation ensure no condensation occurs when warm wheat enters the machine.

The D-mill’s finished product, primarily bread flour, is shipped via truck (about 90% bulk, 10% bagged). Drop bins with fluidized bottoms can load trucks in fewer than five minutes.

Tucker Scharfenberg,
senior managing editor