University of Minnesota Biomass
Hello Casey,
Sorry it has taken me so long to get back to you. I sent your questions around to some of the other researchers I work with. Prof. Vance Morey and Dr. Nalladurai Kaliyan have been doing a lot of work on biomass densification here at the UofMN
Here are some answers to your questions:
what does HHV stand for? I am trying to figure out what is the yearly input in tons of biomass needed to just fuel the heat needs of a plant?
HHV stands for Higher Heating Value which is the amount of heat released during combustion. See this link for more detail: http://en.wikipedia.org/wiki/Heat_of_combustion
You can find a graph showing the amount of biomass fuel needed to supply the heat needs of a 50 million gallon per year dry grind ethanol plant in the ASABE paper I have attached. If you use only corn stover it is about 400 tons (363 metric tonnes) per day
When you all are looking at this study do you envision bales being stored at the field through out the year and a fleet of trucks will delivery them to the ethanol plant at the time they are needed rather than bulk storing at the ethanol plant?
We assumed that the biomass would be densified into pellets or briquettes at a facility separate from the ethanol plant. The ethanol plant would have enough storage to hold about a weeks worth of densified biomass fuel.
Densification, is grinding the way to go with that in order to keep transportation costs lower or can you just delivery bales to the plant where you have a stationary grinder on site?
A response from Prof. Morey:
Grinding is a preliminary step in densification. Grinding probably leads to lower bulk density than bales in the first step. That is something we are working on. I not a big fan of moving a pelleting or briquetting device to the site of the bales to make the pellets or briquettes. I think there is an intermediate stage of grinding followed by compacting the material at the local site, but not forming briquettes, in order to transport to a central facility for making the briquettes. I think this will be operated like a separate business even if it owned by the same people who own the ethanol plant.
He asked the question that a lot of people ask which is if you get the bales delivered to the ethanol plant why do you need to densify. I think we will find that feeding densified material (pellets or briquettes) in to the combustor or gasifier will be important to have predictable performance at the plant. The cost reductions resulting from predictable performance will justify the densification cost. We still need to do the analysis to see if this turns out to be true.
Pellets? Do they add another unnessecary step in this process? Could you turn the biomass to pellets in order to store in a silo on site using the bulk delivery to the site scenario?
Portable pelleting operation, what do you think of a semi trailer with a pelleting system built on it to grind and pellet at the feedstock location and you delivery pellets instead of ground biomass?
This is going to require a lot of trucks and baling equipment, do you see an opportunity for a contract company to provide these services to an ethanol plant. Essentially creating a partnership where a secondary company sources feedstock to the plant and the plant makes the investment in the gasification equipment. Or do you see the ethanol company trying to take on this whole process?
We assume it will be a contracted company, but the ethanol plant will be very closely involved.
Let’s say you are trying to meet the needs of a 50 million gallon facility, what is the radius in miles of the plant that you would need to collect from. I understand this will be based on a % of land you are harvesting off.
This depends on how much biomass farmers are willing to take off their land each year.
Lets say the plant is surrounded by corn fields. The corn yield is 150 bushels/acre, half the above ground weight of the corn plant represents grain, the other half is corn stover. If the farmer is willing to take off 50% of the corn stover each year you would have about 2.1 tons per acre available. The plant needs 132,000 tons per year. So you need about 63,000 acres to draw from. If the area is pure corn ground the radius would be 5.6 miles.
Thanks for taking the time to reply
E85 Conversion Kit
We know that you are visiting here because you want to make a difference and save money on fuel costs. Not only is E85 ethanol motor fuel’s price is cheaper than gasoline, but it is better for the environment. Further, your dollars stay here in the USA since E85 ethanol is American made.
We have purchased other E85 Conversion Kits and tested them in our personal vehicles. As an independent reseller, we have chosen to ONLY sell the FFI Platinum. We will continue independent testing of all brands and should we find one better, we will consider offering that product. We do not accept free test units. We pay for them to keep our testing unbiased.
Your vehicle will have the ability to run on straight gas, straight ethanol, or any combination of the two. The most popular combinations are E85 (85% ethanol and 15% gasoline) or your everyday gas (10% ethanol and 90% gasoline). Please remember that the FFI Platinum will automatically sense the gas to ethanol ratio and make all of the adjustments necessary for a seamless FlexFuel experience
Greenhouse
The primary purpose of the greenhouse facility is to serve as a demonstration greenhouse showcasing new technologies in “real world” conditions for economic development. Designed by the Bioresource Engineering Department of Cook College, Rutgers University and built by the County of Burlington’s Board of Chosen Freeholders, the greenhouse has numerous environmental technologies incorporated into its design. These technologies serve to give the greenhouse a soft footprint on the environment. The greenhouse has been operational since 1996. It is one of the largest research greenhouses in the U.S. with over 46,000 square feet of greenhouse production space and 10,000 square feet of support buildings.
Some of the noteworthy features incorporated into the research facility include:
- Sophisticated computerized environmental controls for 5 separate zones that monitor, control, and record the temperature, light level, humidity and carbon dioxide level for each zone while minimizing energy usage
- Heated floors throughout that serve as a thermal storage device and places the heat where it is needed, in the crop
- High Intensity Lighting to supplement natural sunlight and extend the daylegnth during the lower-light periods of the year (September through April)
- Energy curtains that reduce heat loss, during the night, in winter and reduce the cooling loads, during the day, in summer
- High density polyethylene liners under the greenhouse floors to prevent irrigation water from leaving the greenhouse and going into the ground
- Double-wall acrylic sidewalls to reduce heat loss through the sides of the greenhouse
- High pressure fog cooling system
- Dual-fueled boiler for both landfill gas and natural gas
- Landfill gas fired microturbines and waste heat recovery system
- Automated rolling benches or “Dutch trays” that allow the crop to be brought to the workers in the headhouse and also allow for greater space utilization in the greenhouse
- Recirculating hydroponic irrigation system
- Glass and double layer polyethylene roofing in identical sections to allow for comparison of crop production under both covers
Research at the greenhouse focuses on the economic and crop production impacts of the new technologies. The results are then made available for greenhouse growers (and those considering getting into greenhouse production) to evaluate.
For more photos please visit our online photo gallery.
BioOil
Prepared feedstock (<10% moisture and 1-2 mm particle size) is fed into the bubbling fluid-bed reactor, which is heated to 450–500 °C in the absence of oxygen. This is lower than conventional pyrolysis systems and, therefore, has the benefit of higher overall energy conversion efficiency. The feedstock flashes and vaporizes like throwing droplets of water onto a hot frying pan. The resulting gases pass into a cyclone where solid particles, char, are extracted. The gases enter a quench tower where they are quickly cooled using BioOil already made in the process
The BioOil condenses and falls into the product tank, while non-condensable gases are returned to the reactor to maintain process heating. The entire reaction from injection to quenching takes only two seconds.
100% of the feedstock is utilized in the process to produce BioOil and char. As the non-condensable gases are used as energy to run the process, nothing is wasted and no waste is produced. The uncondensed, flammable gases are re-circulated to fuel approximately 75% of the energy needed by the pyrolysis process.
Three products are produced: BioOil (60-75% by weight), char (15-20% wt.) and non-condensable gases (10-20% wt.). Yields vary depending on the feedstock composition. BioOil and char are commercial products and non-condensable gases are recycled and supply a major part of the energy required by the process. No waste is produced in the Dynamotive process
A fourth product, BioOil Plus, can be produced by adding back the separated char into the BioOil, in a finely ground form of about 8 microns in size.
Fluidized-bed pyrolysis of switchgrass
We have now built a unique pilot-scale reactor that uses a hot sand medium (called a fluidized-bed reactor) to convert perennial grasses to bio-oil and have now tested the reactor on switchgrass. The reactor was able to use switchgrass as a feedstock and produce a quantity of bio-oil that was 60% of the weight of the switchgrass fed into the reactor. We tested the composition and fuel properties of the produced liquid and found that the energy content was about the same as the parent switchgrass but the density was more than 2.5 X greater.
Nebraska Sweet Sorghum
It looks like split-pea soup and tastes like sugar water with a vague vegetative twist. But never mind.
Ishmail Dweikat and John Rajewski don’t have their collective eye on Gatorade as the primary competition for the juice from the 12-foot long, one inch-thick stalks of sweet sorghum they’re harvesting from a University of Nebraska test plot.
Dweikat, leader of sweet sorghum research at UNL, and Rajewski, field manager and plant breeder, are more interested in using these plants rustling in the East Campus breeze as the raw material for future ethanol production.
“If you want a reliable source for ethanol,” Dweikat said, “corn would not be the one.”
Sweet sorghum’s advantages over Nebraska corn are many, he said.
It doesn’t need to be irrigated and goes into dormancy during drought periods. The ratio of energy consumed to energy produced is much higher than corn, and an acre of sweet sorghum can produce as much as 800 gallons of ethanol.
Corn’s ethanol yield is closer to 250 gallons per acre.
Despite what the UNL researchers see as sweet sorghum’s considerable promise, corn growers serving the ethanol market don’t need to leap out of the way just yet.
It will take another year or two to develop the right hybrid, Dweikat said. Harvesting equipment that can crush the juice out of the stalks as it moves through the field is also a work in progress.
“Back in the 1900s, sweet sorghum was used as a source of molasses,” he said.
In a new century, possibilities for what can happen with a plant traceable mostly to Africa are headed in an energy direction.
Can the crop be a major source of renewable fuel?
“It’s very likely it will be if we can get the mechanics worked out for it,” said Rajewski.
Dweikat said Texas and Oklahoma, neither of which is a major producer of corn, are further along in building distilleries to boil the water out of sorghum juice and convert what’s left to motor fuel.
But tall stands of sweet sorghum, which carry seed clusters at the very top, can be grown anywhere corn and grain sorghum can be grown.
In Nebraska, home to gusty winds early and late in the growing season, an adaptation is in the works.
“We’re trying to breed for tall, big stalks without seed,” Dweikat said. “If there’s nothing heavy on the top, it has a much better chance of standing the wind.”
Signs of success at UNL are not exactly taking the ethanol industry by storm. Preliminary checks with the ethanol establishment in other states failed to turn up anybody gushing with enthusiasm.
Brian Jennings, based in Sioux Falls, S.D., with the American Coalition for Ethanol, is among the less than overwhelmed. He sees corn and cellulosic ethanol made from the rest of the corn plant as dominant factors.
“I think corn will remain the centerpiece for years to come,” Jennings said, “and then we will see corn stover and corn fiber and other things like that kick off very soon.”
If sweet sorghum is a better choice, “that would be news to me.”
James Covey, ethanol advocate and state legislator from Custer City, Okla., said his state is moving toward building its first ethanol plant, but will use the same grain supply to make the finished product as plants elsewhere.
Sweet sorghum, said Covey, is “a different breed of pup.”
Dweikat and Rajewski are undeterred and lay out a future in which Nebraska farmers distill their own juice and store it in rubber bladders until it can be picked up by cooperatives and hauled off to make ethanol.
“Of course, economics drives everything,” Rajewski said, “economics and water availability. So we’ll see how that goes.”
The sweet sorghum research is being conducted on dryland plots at UNL’s High Plains Ag Lab near Sidney and at other Nebraska locations. UNL is looking at some alternative ethanol-producing crops for farmers who rely on dryland or limited-irrigation production, according to Drew Lyon, extension dryland crops specialist at the Panhandle Center. Growing dryland corn is risky in the Nebraska Panhandle. Sweet sorghum may be a crop that dryland farmers can grow more consistently and profitably.
In 2007, field studies were conducted at Sidney, North Platte, and Clay Center to determine theoretical ethanol yield from sweet sorghum, corn, and grain sorghum. This work was done by Lyon, in cooperation with other UNL experts, Ismail Dweikat of Lincoln, Charles Wortmann, extension, from Lincoln, and Bob Klein, extension cropping systems specialist at the West Central REC in North Platte.
Preliminary findings indicate that, compared to corn and grain sorghum, sweet sorghum does not produce more ethanol yield per acre, but does produce greater net energy. This results in a net reduction in CO2 emission compared to corn or grain sorghum, and much more energy produced per energy invested. Approximately 250% more energy is produced than invested for sweet sorghum, compared to 50% more produced than invested for corn or grain sorghum. Sweet sorghum produces more net energy because it produces sugar, rather than starch. According to Lyon, less energy is needed to make ethanol from sugar than from starch. Sweet sorghum may require less nitrogen fertilizer input than corn, and may be more water-use efficient than corn.
Some potential problems with sweet sorghum include harvest challenges — for example, what to do with all the biomass and where and how to extract the sugar. The plants are very tall, and seed production is low. Questions also remain about how to feed sugar into a corn ethanol stream.
Sweet Sorgum
Oklahoma State University’s sorghum-related biofuels research is taking a localized approach, with the aim of making possible the effective production of ethanol in the farmer’s own field.
Sweet sorghum can be grown throughout temperate climate zones of the United States, including Oklahoma. It provides high biomass yield with low irrigation and fertilizer requirements. Corn ethanol, in contrast, requires significant amounts of water for growing and processing.
Best of all, producing ethanol from sweet sorghum is relatively easy, said Danielle Bellmer, biosystems engineer with the OSU Division of Agricultural Sciences and Natural Resources’ Robert M. Kerr Food and Agricultural Products Center.
“Just press the juice from the stalk, add yeast, allow fermentation to take place and you have ethanol,” Bellmer said. “Unfortunately, the simple sugars derived from sweet sorghum have to be fermented immediately.”
Throw in the expense of constructing and operating a central processing facility that would only operate the four to five months of the year when sorghum would be available in Oklahoma and the challenge multiplies.
The beginnings of a possible solution presented itself when entrepreneur Lee McClune, president of Sorganol Production Co. Inc., approached FAPC scientists seeking their assistance in testing his newly designed field harvester capable of pressing and collecting juice from sweet sorghum. His proposed Sorganol process involved using the harvester, large storage bladders for fermentation and a mobile distillation unit for ethanol purification.
OSU’s initial involvement in the project was to look at the feasibility of fermenting the juice in the field.
“We’re examining such things as juice extraction efficiency, whether or not pH (acidity) or nutrient adjustment of the juice is needed and various environmental factors,” Bellmer said.
The goal is to make production of ethanol from sweet sorghum economically viable by using an in-field processing system that minimizes transportation costs and capital investment.
Equipment such as the harvester and other technology could be owned individually or cooperatively with a number of producers sharing and possibly helping one another process ethanol from sweet sorghum.
In Oklahoma, the potential processing scenario might look like this: Plant sweet sorghum around mid-April, and then stagger plantings for two to three months. This would provide a harvest window of August through November.
“Ethanol yields in Oklahoma could range from 300 gallons to 600 gallons per acre, depending on biomass yield, sugar content and juice expression efficiency,” said Chad Godsey, biofuels team member and OSU Cooperative Extension cropping systems specialist with the department of plant and soil sciences.
Godsey said the team is working to determine the maximum possible harvest window for sweet sorghum in Oklahoma.
“Obviously, the longer the harvest window, the more ethanol state farmers will be able to produce,” he said.
OSU Biofuels Team researchers also are studying environmental parameters that may affect the feasibility of on-farm fermentation. A producer must be able to ferment the juice in the field during Oklahoma’s harvest season for sweet sorghum, which occurs in the fall when temperature extremes are highly possible.
“Temperature can speed up, slow down or derail the fermentation process,” Godsey said.
Weather data for Oklahoma indicate an average low temperature of about 44 degrees Fahrenheit and an average high temperature of approximately 98 degrees Fahrenheit during the August-through-October period over the past 10 years.
Six test plot sites are maintained at Oklahoma Agricultural Experiment Station facilities across the state, allowing OSU scientists to conduct research on sweet sorghum under local conditions.
“We would like to do with sweet sorghum what the Brazilians have done with sugar cane: In Brazil, sugar cane ethanol provides a large percentage of their fuel needs,” Bellmer said.
The idea of using sweet sorghum for commercial ethanol production is not new. The reason sweet sorghum is not as popular as corn in terms of being a source of ethanol in the United States has been the need to ferment its simple sugars immediately and the high costs associated with a central processing plant that is operated only seasonally.
“By determining a process by which agricultural producers can create ethanol in the field from sweet sorghum, that barrier is removed,” Bellmer said. “Producers will then have a much higher value product to sell.”
USDA Corn Stover study
Determine the amount of crop residues (e.g., corn stover, cover crop) that must remain on the land to maintain soil organic carbon (SOC) and sustain production. Through a series of experiments with factors including tillage and residue removal conducted under several environments, measure biomass production, grain yield, and change in soil organic carbon, and from these measurements estimate the amount of residue needed to maintain soil organic carbon and productivity. Click here to read the study which runs through 2011
ZeaChem
However now a new energy startup called ZeaChem claims to have solved the problem, and that they can now make ethanol at a competitive price.
At its laboratory in Menlo Park, CA, ZeaChem says they have created a new means of developing ethanol from wood chips, switch grass, and several other sources that is more efficient than competing methods. Developed by experts from the Coors brewery, crude oil refining, and other chemical industries, the process involves joining biomass in a fermenter with a naturally occurring microorganism (found in sources such as termites or horse manure) that unlike other methods uses all fractions of the plant, meaning the energy of all fractions of the biomass end up in the product.
According to the company, their process will theoretically produce a maximum 160 gallons of ethanol for every ton of biomass, and a biomass farm with an eight-mile radius could support a refinery producing approximately 300 million gallons of the fuel per year. In addition, ZeaChem says their method is more efficient than others, citing a “net energy ratio” of between 10 and 12, meaning that for every unit of fossil energy used, 10 - 12 units of renewable energy are produced. In contrast, the company claims corn-based ethanol has an approximate net energy ratio of only 1.6.
So what exactly does all this mean for drivers? Well, according to ZeaChem CEO James Imber, the company will be able to produce ethanol at 80 cents per gallon at the plant, which he estimates would equal a price of about $1.50 at the pump. Of course if you were buying E85, the 15 percent gasoline would add additional cost, plus the lower fuel economy would still be a factor. But that price could certainly go a long way toward turning ethanol into a truly viable alternative fuel.
Agricultural lands can provide nearly 1 billion dry tons of sustainably collectable biomass and continue to meet food,
feed and export demands. This estimate includes 446 million dry tons of crop residues, 377 million dry tons of
perennial crops, 87 million dry tons of grains used for biofuels, and 87 million dry tons of animal manures, process
residues, and other residues generated in the consumption food products. The perennial crops are crops dedicated
primarily for bioenergy and biobased products and will likely include a combination of grasses and woody crops.
Providing this level of biomass will require increasing yields of corn, wheat, and other small grains by 50 percent;
doubling residue-to-grain ratios for soybeans; developing much more efficient residue harvesting equipment;
managing active cropland with no-till cultivation; growing perennial crops whose output is primarily dedicated for
bioenergy purposes on 55 million acres of cropland, idle cropland, and cropland pasture; using animal manure in
excess of what can be applied on-farm for soil improvement for bioenergy; and using a larger fraction of other
secondary and tertiary residues for bioenergy.
