The day that hog manure can be transformed into petroleum will happen ‘when pigs fly.’
The pig-flying reference is commonly used as a sarcastic quip to emphasize the sheer foolishness of an idea or plan. But don't tell that to a small group of chemical and mechanical engineers engaged in a pilot project to convert swine manure to petroleum-based products.
At the root of the project is an engineering company called Innoventor. The company, with the help of grants from the Environmental Protection Agency, the Missouri Pork Producers Association and the Missouri Department of Agriculture, has been tending the manure-to-energy prototype adjoining a 600-head finishing barn on the home farm of Rick Rehmeier near Augusta, MO.
Innoventor promises approaching zero emissions at the property line, retained nutrients for crops and a positive return on investment.
If you think that's too good to be true, then you probably haven't heard about thermo-chemical conversion (TCC). TCC uses intense heat and pressure to break down the molecular structure of manure to a raw, basic form of petroleum that resembles tar pitch, commonly used in roofing and road repair.
The process, first heralded by University of Illinois researchers in 2004, caught the attention of Innoventor, a multi-disciplinary engineering company headquartered in St. Louis, MO.
Project engineer Gary Winkler explains the process begins by pumping liquid manure from one of four chambers of the barn's under-slat storage pit.
Next, the product is pumped at high pressure through a pair of heat exchangers and into the reactors.
Currently, two reactors are being tested side-by-side to see which is best. “We basically control the pressure, temperature and time the slurry spends in the reactor. As it comes out of the reactor at a high temperature, we run it through the heat exchangers to heat up the slurry going in,” Winkler notes.
“Going in we have manure (solids) and water. Coming out, we have a thick, tarry product which can be burned to generate electricity to be used on-site or sold to an electricity provider; or we can make an asphalt binder, the application we are most excited about,” he continues.
“Our tests have shown the product has really good properties for being an asphalt binder. If we heat it up 15-20 degrees, it will flow like roofing pitch — with a consistency like molten taffy. It will bind with almost anything it touches,” he adds.
For road surfaces, the product would be combined with an aggregate to form a hot mix that would be cheaper than the asphalt currently used.
“Having options is good because pricing it is a little unpredictable. So, if refinery capacity shifts over to making asphalt binder and the prices go down, then I think the other applications are more advantageous,” Winkler notes.
The cost structure for the business model is based on different uses of the product, explains Rick Lux, applied technology manager at Innoventor.
“The value of the TCC product is based on one of several options with which we've run different models to establish the value for each option. The pork producer would get a percentage of that.
One option is electricity. The refined product would drive a generator to produce electricity for the farm, with excess sold to the electrical grid supplier. The asphalt binder has many different uses — crack sealant, roofing, road paving, a specialty coating and even clay pigeons. “We're going to lay 500 ft. of road this fall in Missouri using a mixture of this binder to compare with regular asphalt binder to see how it holds up,” Lux says.
The prototype at Rehmeier's farm is sized for a 1,000-head finishing unit. “In terms of the dimensions of a unit, we can get everything we need on a trailer. It will be a lot more compact (than the prototype),” Winkler notes.
Operating around the clock and at full potential, a 1,000-head finishing barn could produce about 70-100 gallons of final product per day. The prototype uses electricity as the primary energy source. By reclaiming heat and routing it through the heat exchangers, Winkler estimates the energy efficiency ratio at 3 or 4 to 1. “It will take one unit of energy — say Btu's per hour — going into the system, and what is stored in the product will be about 3-4 times that,” he explains.
Innoventor's goal is to develop a system that can be easily transported to a site and installed, preferably permanently.
Lux says their modeling efforts show the most cost-effective model would handle manure from 5,000-10,000 head on a single site.
“We couldn't have one unit servicing sites that are a mile apart, for example. You wouldn't want to run that much piping and it would be impractical to truck it to one site. In our business model, once we really get to know how to build a system effectively, instead of buying the parts, we will manufacture them, cutting costs further,” he explains.
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In calculating the payback potential, Lux says a gallon of manure slurry yields 5% oil and 95% “black water.” A large portion of the nitrogen, phosphorus and potassium in the slurry remains and can be used as crop nutrients. “What comes out is basically the same (nutrient value), minus the manure particles,” Lux says.
In addition to the potential for producing a petroleum derivative, the company's intent is to help alleviate concerns about odor and water quality.
“We have a technology that can approach zero emissions at the property line,” explains Lux. “We'll get rid of your lagoon, we'll clean up the air coming out of the buildings and we'll turn the waste product into a revenue stream.”
“There are two primary sources of odor in a confinement hog operation — the lagoon (manure storage unit) and confinement exhaust,” Winkler agrees. “We essentially convert the lagoon to a freshwater pond. All of the solids will be removed and the water coming out of the reactor will be cleaned up, as well as kill any disease organisms, but it will leave nutrients in the water.”
Odor reduction is accomplished through air scrubber technology, on which Innoventor also holds a patent.
The water-based air scrubbers, fitted to exhaust fans, draw air across a cascading waterfall that captures about 80% of the animal dander and dust — the primary source of odor — and expels the scrubbed air into the atmosphere, Lux explains. The “dirty” water is returned to the pit.
“There's still a fair amount of N in that water. Some of it goes into the oil, but if we continue looking at the different possibilities, we may squeeze some more N into the water and not into the oil,” he says.
“We have a business plan that has been presented to industry-leading experts, and we are actively pursuing investors to get this out there on a number of farms, targeting the main hog-producing states,” explains Kent Schien, CEO of Innoventor.
Innoventor is registered in several states for federal stimulus funds. They have a staff of 60-70 engineers in several disciplines — mechanical, chemical, civil, stress and aerospace — who have successfully completed innovative projects across many key industries.
“A lot of what we see for the future is growth in three sectors — aerospace/defense, medical and renewable power/energy,” Schien says.
Additional information about Innoventor can be found at: www.innoventor.net.