Reprinted from the December Cedar Valley Business Monthly magazine
GRUNDY CENTER — In 2007, when a fire at the Environmental Lubricants Manufacturing plant in Plainfield damaged the facility, a search began for a new way to process grease and lubricants. University of Northern Iowa professor Lou Honary, who founded the National Agriculture-Based Lubricants Center (UNI-NABL), was an owner of ELM and began searching for alternative methods of heating oils.
Of all the unique processes researched, they chose microwaves as the best alternative.
After proof of concept in the laboratory, Honary and his associate, Wesley James, connected with Cedar Rapids based AMTeck Microwave Technology to test commercial-scale microwave systems for heating industrial products. In 2010, ELM began manufacturing soybean oil-based grease and lubricants commercially using microwaves in a facility in Grundy Center.
“There is a general misconception that you cannot put metal objects in a microwave; and that’s why no one had thought about using microwaves on metal vessels for cooking or heating for reaction,” Honary said.
Instead, for years the industry has relied on steam or hot oil heat transfer technologies. Both are inefficient and dangerous. The fire that destroyed the ELM plant started when the heat transfer oil system burst a pipe and caused smoke, which eventually led to fire. Steam systems are known for their hazards because they are under high pressure.
Honary said microwaves are much safer and easier to use, but people don’t understand them. He explained how heating milk on a stove requires stirring or the milk will burn at the bottom of the pan where it is in contact with the fire or heating element. But putting a cup of milk in the microwave heats the milk quickly and does not require mixing or stirring. This is because microwaves excite the milk’s molecules, creating frictional heat. The cup may not even get hot unless it is made of materials that absorb microwaves.
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ELM has been using 500- to 800-gallon metal vessels hooked to 75-kilowatt microwave generators. The microwave generators produce radio waves that are sent through specially designed duct-like passages called waveguides and enter the metal vessels and heat the products. The waves can actually penetrate the product and cook from the top.
A pump is used to circulate the colder products from the bottom of the tank to the top to expose them to the waves.
Honary said manufacturing ketchup is an example of a product that conventionally requires a jacketed or double-layer vessel. Steam is pumped into the jacket of the vessel to heat up the walls of the vessel to heat the water, tomato, sugar, etc. in the inside of the vessel. Since the walls are hot, large mixing arms are needed to scrape the hot walls inside of the vessel and prevent the product from sticking or burning. This, in turn, requires expensive gear boxes to be placed on top of the vessels with electric motors to drive them.
A microwave vessel can be single wall and there is no need for scraping the inside walls of the vessel. The equipment cost could be a tenth or less, and the process efficiency is much higher than steam-operated systems, Honory said.
During the last nine years, Honary has presented the now-patented technology at various national and international conferences. Advances have since been made to the technology so that it can be used to process other products, including food and pharmaceutical products. Honary is enthusiastic about this technology because he believes “it goes far beyond grease processing and far beyond Iowa. It has the potential to reduce the worldwide processing energy consumption by more than 50%.”
ELM has now licensed the technology from UNI and has started a subsidiary company called WAVEtek Process System to commercialize the concept. Honary compares the use of microwaves in processing products to the transformation from current gas engines to electric vehicles.
“Ten to 15 years from now it is likely that most of our cars will be electric that will be more efficient and cleaner. It is also likely that microwaves will be one of the primary methods of heating for processing industrial, pharmaceutical and food products,” he said. “The process will save energy and reduce emissions to address environmental concerns. Perhaps once again technology developed in Cedar Valley will become known and used worldwide.”