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Published August 17, 2010, 09:25 AM

ND manufacturer offers ‘100 percent efficient’ biomass drying

BISMARCK, N.D. — Mike Robb can see it all: In the near future, farmers no longer will need to buy expensive propane or natural gas to dry their crops.

By: Mikkel Pates, Agweek

BISMARCK, N.D. — Mike Robb can see it all: In the near future, farmers no longer will need to buy expensive propane or natural gas to dry their crops.

Instead, they’ll retrofit existing grain dryers with one of his biomass-burning combustion systems. Instead of propane, they’ll fire up their grain dryers with a variety of biomass sources they’ll either collect on their own farms or haul back from processors.

In the past five years, Robb and his colleagues have developed and have started patent applications on a furnace prototype that he says can do that. The system offers continuous, automatic feeding, or “stoking,” and is designed to shift seamlessly among different fuels — sunflower hulls, corn stover, bean crop residue — on the go, keeping the furnace at a constant temperature all the while.

The goal is to drastically cut drying costs while producing an ash byproduct that can be added to the soil as a beneficial additive.

The prototype furnace is running in a manufacturing company headquarters that Robb has run for the past 30 years in a Bismarck, N.D., industrial park. He intends to manufacture the combustion units for the system in Bismarck. A Fargo, N.D., company will assemble the heat exchanger, or furnace, and then ship it as a complete unit. A range of furnace models will be labeled by their Btu output and will be marketed from the Fargo-Moorhead area starting late this summer. The marketing company will install it and provide any repair or service support, Robb says.

One of the machines will go to a Minnesota seed farm this fall, and other farmers are considering it. Among other things, the company will have a booth at this year’s Big Iron Sept. 14 to 16 in West Fargo, N.D.

History in heat

Robb has a long history in heat.

He grew up in Bismarck, where his father, a World War II vet, owned an electrical installation company. Mike worked briefly with his father, and graduated from Bismarck High School in 1961. He served as a hitch as an electronics technician in the Navy and then returned home, where he married and started a real estate land development business. He developed two subdivisions in town and still owns a utility company that supplies water and sewer service to them.

In the late 1970s and early 1980s, the development business slowed down with double-digit inflation, so Robb reinvented himself.

He started teaching himself the “combustion business.” In 1980, he started a “coal stoker” furnace and boiler manufacturing business that he called King Coal Furnace Corp. In 1983, the company obtained a patent on a rotating stoker. King Coal built and installed thousands of residential boilers and forced-air furnaces in a five-state area, but sold the residential part of the business in 2000. He kept the commercial and industrial end.

King Coal supplies furnaces for numerous applications. In 2009, the company built a commercial-grade system in the Bismarck Aquatics Center, a $7 million complex that uses urban tree waste from the Bismarck landfill to heat water and the building, saving excess of $100,000 over the cost of natural gas. King Coal’s piece of that project was about $600,000.

“We have been building industrial wood-fired systems for the wood industry — cabinet and hardwood flooring — for several years. They’re used in kiln-drying industry, and they’re all over Minnesota and Wisconsin, and as far south as Kentucky.”

About five years ago, Robb started thinking about applications for the on-farm and agricultural market.

“I figure, we’re near the epicenter of the grain-drying region,” Robb says. “I thought there was an opportunity, with propane prices that can hamstring farmers and kill their bottom line.”

DDGs and beyond

Initially, one of the focus points was to see how the system would work with dried distiller’s grains, or DDGs.

“That, in our estimation, was the most difficult thing to burn, but it turns out it burns beautifully on our stoker,” Robb says.

“We discovered, to our delight, that it burns a lot of other fuels equally as well,” Robb says. “That we find interesting from the perspective of a farmer who has a variety of byproducts that could potentially be burned to displace propane or natural gas as the heat source for grain drying.”

Some of these sources are obvious.

For instance, “North Dakota is the premier volume grower of sunflowers,” Robb says. “You have over a million acres of sunflowers this year. Any farmer who raises sunflowers may not know it, but he has enough screenings in his crop to dry all of his crops.”

Of course, Robb is talking about 2,000 acres or so and who may have corn or something else to dry.

“They can bring the sunflower crop in and screen it out and utilize it for free, instead of buying the screenings,” he says.

Ditto for a variety of other crops — corn, beans and any type of crop they need to dry down. They can burn turkey and chicken litter, providing it’s reasonably dry and friable (not frozen in big chunks).

With corn stover and cob waste, “you can recover a portion, grind it and use it directly in our combustor. Trash that comes out of a field of soybeans would be another excellent source of fuel — baled, ground and burned.”

The system will “burn anything that is 1 inch in diameter or smaller. It has to be ground to a consistent size in a tub grinder. It can burn

‘run-of-mine’ coal, or stoker coal. That’s the stuff the railroad hauls.

No other stoker system can do that unless you have a power plant,” Robb says. “The stoker system, regardless of how much ash is in it, rejects it and it’s augered out automat-

ically when it’s combusted. You don’t have to baby-sit a stoker. All a farmer has to do is make sure it has fuel.”

One feature is an Internet connection, where the farmer can monitor it from his laptop.

Moisture no problem

One key to the system is that moisture content is not an issue.

Lignite coal puts out 7,000 Btus per pound and is about 38 percent water as it is mined.

Sunflower hull screenings — immature smaller-sized seeds, twigs and nonseed biomass — offer 9,000 Btus per pound, which is “way beyond lignite coal, and rivals Wyming coal, Robb says.

“It burns beautifully,” he says.

The screenings usually are dried with the crop.

Corn cobs produce about 7,000 Btus per pound. The cobs and stover have to be ground down to an inch or less in diameter.

“You can take that type of material, put it in this combustor, and you can dry your corn with it. Instead of these guys shelling out hundreds of thousands of dollars over the life of their system, they can put (those funds) in their pocket,” he says. “It depends on the specific drying season, but most people will be able to pay for it in a year. That’s a substantial payback.”

The prototype has a chimney, but that’s only to get rid of excess heat in a boiler system, while a commercial air-to-air system essentially would use all of the heat internally.

Many sizes, many fits

King Coal will sell 1 million- to 10 million-Btu systems for most farm applications, but larger, commercial systems may go to 50 million Btus for commercial elevators.

The prototype burner is 4 feet wide and 6 feet long, but commercial systems likely will be larger. The prototype is inside a building, but the commercial models can be placed outdoors or outside in the weather and connected to a grain dryer with round duct work. Units provide forced-air, indirect heat.

A 2 million-Btu unit would measure 6 feet wide by 12 feet long and be 8 to 10 feet tall. It will be transportable, so it would come as a complete unit, with all the electrical work done. It would be a matter of setting it on the site, skid-mounted, and hooking up duct work from the combustor to the dryer and turning it on.

With a typical farm unit, the heat would be indirect, air-to-air, so that the combustion gases will be contained in a heat exchanger, with air blowing around the heat exchanger.

“There would be no direct flame exposed to the products, so the system would be much safer. The design is a five-pass heat exchanger — very efficient for converting solid fuel into heat,” he says. “The design of the system allows us to take waste heat that normally would go up a chimney and use nearly 100 percent of it in the drying process.”

Because of this, it will reduce the solid fuel needs for similar systems by 30 percent.

Robb underlines the fact that his company isn’t in the fuel business, and it doesn’t make or install grain dryers.

“We’re simply providing the heat source for the grain drying — the combustion and the heat recovery,” he says.

Ag market interest

Robb is very optimistic about agricultural and biomass applications.

“We see this in the tens of millions or hundreds of millions in growth potential,” he says.

Robb says it’s difficult to specify a price for the machines.

“That depends on how much equipment they want to supply — their fuel handling, storage, and conveying,” he says.

A rough rule of thumb might be that farm system will cost $80,000 to $300,000, for the furnace alone.

A Juneau, Alaska, brewery has purchased a 10 million-Btu boiler. The system is under construction now, so that the brewery can use its own distiller’s grains byproduct to generate high-pressure steam for brewing, displacing $2.50-per-gallon diesel fuel.

On the ag side, Anderson Seed of Mentor, Minn., is the first in the region with a contract to put one of the furnaces into place. It’s a 12-month operation and will be used to dry sunflowers. Anderson Seed is installing a 2 million-Btu unit, which is likely to be in place by October or November.

Robb thinks farmers won’t flinch at those prices when they see the advantages.

“You can buy a propane burner for a few thousand dollars, yes, but that isn’t the big item,” he says. “The big item is the $50,000 per year or more they spend on buying propane.”

He works out the equation this way: At a cost of $1.50 per gallon for propane, the cost for fuel for drying is about $16.37 per million Btus.

“Lignite coal in this region is about $4 per million Btus. But you can buy sunflower screenings for $30 a ton for bedding. That works out to about $1.65 per million Btus. So if you have a 6 million-Btu furnace, at $1.65 per million Btus, you’re paying $10 to $12 per hour, vs. hundreds of dollars per hour for propane. That’s why we’re at the point where we can take this to market.”

Installation, operation

The commercial furnace model will be skid-mounted, so it can be picked up and set on the ground.

It’ll hook up the ductwork to their dryer and hook up an electrical feed.

“By the way, it doesn’t matter if they have three-phase on their farm because this will convert single-phase 220 volt to three-phase 220 power,” he says.

Customers will install a hopper bottom bin, much like a grain bin, which would store things like sunflower hulls. These will flow out of an epoxy-lined bin and into a fuel feed auger that will take it into the combustion hopper, where it will be automatically fed and modulated.

“The combustion rate will modulate up and down,” Robb says.

In the fall, when there are wide temperature fluctuations, the system will automatically compensate by stoking more fuel to compensate for the colder air.

“This system redistributes on a continuing basis the products of combustion on an even, flat surface,” he says. “There is an anti-gravity combustion device that distributes and redistributes the fuel automatically as it burns, so the fuel bed remains very thin and receives a proper ratio of air to fuel that nobody has been able to obtain until now.”

The unit automatically removes ash from the combustion zone, or furnace.

There is a proprietary system, which uses air distribution on the edges of the fuel pile, which more completely burns the material above the fire. The system is designed to redistribute the fuel as it’s burned, cutting down on the particulate production, the energy waste and cutting pollution.

The system is computer-controlled to maintain very low emissions. A farmer who installs the unit can monitor the machine, remotely with a dial or a keyboard. The system can be wired through the Internet to his laptop computer in the house or elsewhere, so he can monitor how the dryer is doing.

Robb says the system isn’t a brand new, but it’s a new application.

“We’ve taken something here, that we’ve known about for a very long time and spent a lot of research and development — five years on R&D — to bring this to market as brand new,” he says.

Looking ahead

King Coal is a private company and isn’t obliged to disclose its business volume, but Robb is willing to acknowledge sales are “in the seven-figure column.” He thinks that, if this product takes off, that could grow substantially.

Robb sees enough potential in the business that his family has joined him. His son-in-law, Jon Dockter, who has a degree in engineering and worked for 10 years in the airline industry in Minneapolis, is working with the company.

Among others, Robb has been consulting with longtime friend Jack Johnson of Fargo, who was an early executive of Steiger Tractor Co. Melroe is working with the business as it expands into agriculture.

King Coal is “heading in a direction that I feel, within the next few years, is entering a billion-dollar market,” Robb says.

“God only knows where all of this

is going to go,” he says. “You know things are way out of line in terms of the cost. Farmers don’t have any control over that. They’re behind an eight-ball when it comes to guys who predict what propane and natural gas will cost.”

He doesn’t see anything about biomass prices that will change the prospects for his products, but the price of propane typically just goes up, especially at times when farmers need it most.

“On the farm, these guys who raise sunflower or corn, they’re unknowingly creating a byproduct that can be made into a viable fuel source that can dramatically reduce their operating expenses,” he says.