Need to clarify sugarcane juice leads to new invention

Linda F. Benedict, Blanchard, Tobie M.

Figure 2, provided by Sterling Sugar Mill, shows how the TRD works in the clarifier design. The exit points of the pipes are supplied with TRDs that cancel momentum of the feed juice, thus eliminating turbulence eddies. For the past several seasons, these new clarifiers have been outperforming the existing design. Chromepion, an engineering company, purchased the exclusive license from the LSU AgCenter to market the invention worldwide.

Figure 1A, left, shows what happens when colored liquid is added to the tank without the turbulence reduction device (TRD). Figure 1B with the TRD shows calmer water.

Figure 1A

A key step in processing sugar is removing solid particles from the sugarcane juice because the juice naturally contains dirt particles and plant residue. The clarifiers that sugarcane mills have used for decades are expensive to operate and are inefficient.

LSU AgCenter chemical engineering professor Vadim Kochergin works with the sugarcane industry and knows how ineffective these clarifiers are at allowing the solids to settle in the liquid.

“When you introduce liquid into a clarifier, it creates a turbulent jet, and this jet mixes it all up and prevents it from settling,” Kochergin said.

In conventional clarifiers, the liquid typically travels horizontally outward. This horizontal movement slows throughput and creates circular motion inside the clarifier. Kochergin said multiple studies have revealed that the inefficiencies of the clarifier are caused by the presence of large-scale eddies caused by horizontal flows.

Kochergin saw the need for reduction or elimination of these flows to optimize the clarification process. So he developed a turbulence reduction device that solves some of the problems of a conventional clarifier.

“The initial idea was not working well, so we took a piece of two-by-four, stuck it in there, and it started working. It took off from there,” he said.

Working with a graduate student, Kochergin created a working model. He said it took a while to tweak the design. He calls the system Louisiana Low Turbulence Clarifiers.

“The new device allows for reduction of the scale of turbulence within a clarification vessel by minimizing the momentum of the liquid jets at the entry into the clarifier,” he said.

Figurers 1A and 1B illustrate the flow patterns when colored water is introduced into the tank through a single pipe or through the same pipe supplied with a turbulence reduction device (TRD). The new device does not allow any significant disturbance in the vessel.

A few sugarcane mills in Louisiana have put the device to commercial use. Figure 2, provided by Sterling Sugar Mill, illustrates how the new invention was incorporated into the complete clarifier design. A simple juice distribution system comprises a number of feed pipes uniformly distributed over the cross-sectional area. The exit points of the pipes are supplied with turbulence reduction devices that virtually cancel momentum of the feed juice, thus eliminating turbulence eddies.

Kochergin said the new design is working well in the sugarcane industry. The factories report that they lose less sucrose in the clarification process. The new model also is about 35 to 40 percent of the cost of traditional clarifiers and is more energy efficient.

The device could also be used in other industries.

“We designed it specifically for sugarcane application, for settling solids and dirt out of the juice, but it can be used anywhere separation of solids is critical, such as wastewater treatment,” Kochergin said.

Chromepion (formerly American Utility Metals), an engineering company involved in sugar industry applications purchased the exclusive license from the LSU AgCenter to market the new invention.

Tobie Blanchard is an associate communications specialist with LSU AgCenter Communications.

(This article was published in the fall 2012 issue of Louisiana Agriculture magazine.)

1/14/2013 9:17:45 PM
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