360° Kascade discharge removes bottleneck in screening of liquid biological fertilizer
PRINCETON, IL—AgriEnergy Resources boosted throughput of a circular vibratory separator 250-300 percent by employing a 360° discharge Kascade deck that eliminated a restrictive build-up of rope-like sludge around the screen circumference.
In one hour, the 60 in. (1525 mm) diameter separator now processes 9000 gallons (34,000 liters) of liquid biological fertilizer versus 3000 to 4500 gallons (11,350 to 17,000 liters) previously. AgriEnergy saves nine worker-hours of downtime per week by minimizing the need to stop the separator, remove the screen deck, wash off sludge build-up, replace the screen and re-start the process. Labor reductions and productivity increases paid for the added equipment in less than one year.
To increase production by 30 percent, the company installed a circular vibratory separator (its second) fed by a 3000 gal (11,350 l) and a new 6000 gal (22,700 l) mixing tank, but the rope-like build-up of sludge restricted screener capacity by 20 to 30 percent.
Preventing Sludge Buildup
The conventional discharge spout of the company's 60 in. (1525 mm) diameter screener exposed only a fraction of the screen's periphery through which sludge could exit, creating a rope-like build-up of sludge riding around the screen circumference.
AgriEnergy added hollow plastic anti-blinding rings intended to dislodge sand and large particles from screen apertures but with unsatisfactory results.
AgriEnergy had considered adding another 48 in. (1225 mm) diameter circular vibratory separator, but Kason representative, Bob Steiner of Windum Process Equipment, Saint Charles, IL, recommended the less costly Kascade deck after successfully screening samples in Kason's laboratory.
The Kascade deck discharges material 360° around the screen's periphery, reclaiming 100% of the screen surface area and reducing screen wear. Merlin Nussbaum, fertilizer production manager, says, "The Kascade deck knocks off the ring of material right away."
Processing Liquid Biological Fertilizer
Compost suspended in water, stored in 3000 and 6000 gallon (11,350 and 22,700 l) agitated tanks, is pumped at 200 gpm (750 l/min) to the circular vibratory screener that separates it using a 120 mesh screen. Sludge exiting the discharge port at the side of the Kascade deck falls into a dumpster, while the liquid extract containing clay and other particles smaller than 120 mesh, flows from a discharge spout to a liquid holding tank. It is then pumped to one of thirteen 3000 gallon (11,350 l) storage tanks in which the particles settle out for five days.
For the first of two product applications, liquid extract containing the 120-mesh product is pumped directly to tanker trucks that deliver it to farms where it is applied by tractor-pulled sprayers or custom floater spreaders.
For applications requiring 200-mesh particle sizes, 120-mesh extract drawn from the tanks runs through the 60 in. (1525 mm) diameter, 200 mesh screener, and is used for drip tape irrigation.
Adding a Screener Proved Cost-Efficient
Previously, the company processed both the 120 mesh and 200 mesh products with the original 48 in. (1225 mm) diameter circular separator, which had a 50 mesh screen on the top deck and a 120 mesh screen below. Operators changed the bottom screen between 120 and 200 mesh sizes and rearranged hoses between the settling tanks and separator, incurring nine additional hours of downtime weekly, and limiting production to 3000 gal/day (11,350 l/day).
Adding the second mixer and second circular vibratory separator with Kascade deck enabled the company to process 9000 gallons (34,000 l) per day.
"First we tried filters; they didn't work. Then we tried circular vibratory screeners; they worked well. Then we added the Kascade deck, which works better yet.
"The deck easily handles the increased production in less time," says Nussbaum. "If anyone's removing solids from liquid, this is the way to do it."
ScreenTips Vol 16 Num 1