Converting Waste to Diesel Takes Guts, Tires, Plastic…
Changing World Technologies Inc. commercialized a process that mimics the way nature creates fuels through extreme pressure and heat without hazardous emissions. The company is currently selling renewable diesel produced from turkey processing scraps, and soon plans to deploy its municipal solid waste process technology.
The concept of turning wasted material into useful products is what makes the biomass world revolve. The obvious benefits and opportunities have inspired thousands of ideas and theories on how to turn various wastes into energy, including electricity, natural gas, steam, fuel cells and fuel. Yet few of these technologies have actually resulted in the building of a pilot facility, much less a commercial demonstration plant.
"There's a big difference between a pilot plant and a commercial demonstration facility," says Brian Appel, chairman and CEO of New York-based Changing World Technologies Inc. (CWT). CWT has developed one of the few waste-to-energy technologies to reach the commercial level, but commercialization is just one of many factors that distinguish this company. The company was named to Scientific American's 50 in 2003 in the energy category for its work to devise a method of turning solid waste into oil.
CWT's process sets the company apart from the rest of the pack. Many waste-to-energy technologies successfully produce electricity and methane by using a form of combustion. CWT's thermal conversion process (TCP), patented in 1993, is unique because it successfully recaptures the hydrocarbons and converts it into a renewable fuel without producing emissions.
"There's a big difference between a pilot plant and a commercial demonstration facility," says Brian Appel, chairman and CEO of New York-based Changing World Technologies Inc. (CWT). CWT has developed one of the few waste-to-energy technologies to reach the commercial level, but commercialization is just one of many factors that distinguish this company. The company was named to Scientific American's 50 in 2003 in the energy category for its work to devise a method of turning solid waste into oil.
CWT's process sets the company apart from the rest of the pack. Many waste-to-energy technologies successfully produce electricity and methane by using a form of combustion. CWT's thermal conversion process (TCP), patented in 1993, is unique because it successfully recaptures the hydrocarbons and converts it into a renewable fuel without producing emissions.
In the process, organic waste material is converted into renewable diesel, solids and specialty chemicals. The renewable diesel is different from biodiesel because it doesn't contain alcohol. The process applies indirect heat and high pressure to emulate the Earth's geothermal process of converting organic matter into fuel. Thus, instead of changing the chemical composition through incineration, it simplifies the existing complex polymers into their smallest units, which can then be converted into new fuels.
Here's how the TCP works. The feedstock is first prepared with water and ground into slurry. The slurry is preheated to reaction temperature using high-pressure steam energy. Appel says the use of pressure makes the process efficient, with a net energy balance greater than seven. The heat comes from a boiler, which is powered by renewable diesel produced at the plant. The boiler heats water, which is contained in large pressure vessels.
The process is efficient because the water isn't allowed to vaporize. "It doesn't take a lot of energy to heat water up to the boiling point," Appel says. "It takes all the energy to cross that threshold from the liquid to the vapor phase, where you're constantly losing that energy to that vapor phase when you make steam. Instead of spending all that energy evaporating the water, we use it as part of the process."
Keeping the water under pressure enables the boiler to heat the water up to 500 degrees Fahrenheit, which creates 600 to 700 pounds of pressure. "Once you're done cooking the material—when you let that pressure down—you get all of that energy released in the form of steam, which is used to preheat the incoming material," Appel says. "So not only are you not wasting energy evaporating off water that's in everything, but you're also then using that high-value steam as an energy source."
From the preheating treatment, the slurry is placed into a depolymerization reactor, where high pressure and heat separate out the bulk of the inorganic material. That organic material is then subjected to even higher temperatures and pressures in the hydrolysis reactor. Here, the water acts as a hydrogen donor to further break down complex molecules into shorter, useful and similar hydrocarbon molecules.
Finally, the molecules are separated into gases, renewable diesel, water and remaining solids. "After you go through the hydrolysis reactor, you then go through a series of polishing steps that are filters, dehydrators and normal steps that would be at a typical refinery to meet final product specification," Appel says.
Because the TCP doesn't incinerate or combust the waste, it doesn't produce harmful emissions. "Whatever is in the material is going to come out in its elemental form as a hydrocarbon," Appel says. "The typical bad actors we associate emissions regulatory policy around usually are from incineration- or combustion-type technologies." Chlorine, for example, isn't bad in itself, but when it's exposed to an open flame, toxic complex chlorine compounds are formed. Because nothing hits an open flame in the TCP, no such emissions are created.
The process is currently being used at CWT's commercial demonstration facility, Renewable Environmental Solutions LLC (RES) in Carthage, Mo. The facility, developed in partnership with ConAgra Foods and commissioned in 2004, processes agricultural waste—mostly turkey fat, bones and feathers. It has a nameplate capacity of 8 MMgy but is currently producing at approximately 70 percent capacity.
Though Appel says the fuel has performed well in blendability tests, the company isn't selling to the blend market at this time. RES diesel is used unblended in commercial industrial boilers within 100 miles of the facility. "We don't need a lot of customers because these are large boilers," Appel says. A customer with a 1,500-horsepower boiler uses more than 2 million gallons of fuel per year to make steam.
Here's how the TCP works. The feedstock is first prepared with water and ground into slurry. The slurry is preheated to reaction temperature using high-pressure steam energy. Appel says the use of pressure makes the process efficient, with a net energy balance greater than seven. The heat comes from a boiler, which is powered by renewable diesel produced at the plant. The boiler heats water, which is contained in large pressure vessels.
The process is efficient because the water isn't allowed to vaporize. "It doesn't take a lot of energy to heat water up to the boiling point," Appel says. "It takes all the energy to cross that threshold from the liquid to the vapor phase, where you're constantly losing that energy to that vapor phase when you make steam. Instead of spending all that energy evaporating the water, we use it as part of the process."
Keeping the water under pressure enables the boiler to heat the water up to 500 degrees Fahrenheit, which creates 600 to 700 pounds of pressure. "Once you're done cooking the material—when you let that pressure down—you get all of that energy released in the form of steam, which is used to preheat the incoming material," Appel says. "So not only are you not wasting energy evaporating off water that's in everything, but you're also then using that high-value steam as an energy source."
From the preheating treatment, the slurry is placed into a depolymerization reactor, where high pressure and heat separate out the bulk of the inorganic material. That organic material is then subjected to even higher temperatures and pressures in the hydrolysis reactor. Here, the water acts as a hydrogen donor to further break down complex molecules into shorter, useful and similar hydrocarbon molecules.
Finally, the molecules are separated into gases, renewable diesel, water and remaining solids. "After you go through the hydrolysis reactor, you then go through a series of polishing steps that are filters, dehydrators and normal steps that would be at a typical refinery to meet final product specification," Appel says.
Because the TCP doesn't incinerate or combust the waste, it doesn't produce harmful emissions. "Whatever is in the material is going to come out in its elemental form as a hydrocarbon," Appel says. "The typical bad actors we associate emissions regulatory policy around usually are from incineration- or combustion-type technologies." Chlorine, for example, isn't bad in itself, but when it's exposed to an open flame, toxic complex chlorine compounds are formed. Because nothing hits an open flame in the TCP, no such emissions are created.
The process is currently being used at CWT's commercial demonstration facility, Renewable Environmental Solutions LLC (RES) in Carthage, Mo. The facility, developed in partnership with ConAgra Foods and commissioned in 2004, processes agricultural waste—mostly turkey fat, bones and feathers. It has a nameplate capacity of 8 MMgy but is currently producing at approximately 70 percent capacity.
Though Appel says the fuel has performed well in blendability tests, the company isn't selling to the blend market at this time. RES diesel is used unblended in commercial industrial boilers within 100 miles of the facility. "We don't need a lot of customers because these are large boilers," Appel says. A customer with a 1,500-horsepower boiler uses more than 2 million gallons of fuel per year to make steam.
The industrial boiler market has been a good fit for the company. Local distribution has freed RES from high-distribution infrastructure costs. Additionally, boilers typically can accept less-refined fuels, giving the company more flexibility to refine its technology. The only downfall of marketing to fixed-engine markets is that the fuel sells for less than it would in the transportation market. To make up for the lower revenue, CWT produces a fertilizer coproduct from animal and agricultural waste that is registered for use in Missouri, Kansas and Oklahoma.
The TCP technology was first developed in CWT's research and development, and engineering support facility in Philadelphia. The test facility was opened at its site in the Philadelphia Naval Yard in December 1999 and served as a pilot facility for the thermo-depolymerization process technology (later renamed thermal conversion process). Today, testing at this facility is focused on adapting the technology for new feedstocks, such as mixed agricultural wastes, municipal solid wastes, mixed plastics and tires. Specifically, it involves working with shredded residue waste, which is the plastic and rubber left over from shredded automobiles and appliances.
This mixed waste has a low value, and needs to be separated and prepared. "Those products are going to be a bit different than what you have from animal and agricultural waste," Appel says, describing the challenges associated with this new feedstock. "You're starting with different material and there's a lot more material that doesn't have the value of fertilizer."
The TCP technology was first developed in CWT's research and development, and engineering support facility in Philadelphia. The test facility was opened at its site in the Philadelphia Naval Yard in December 1999 and served as a pilot facility for the thermo-depolymerization process technology (later renamed thermal conversion process). Today, testing at this facility is focused on adapting the technology for new feedstocks, such as mixed agricultural wastes, municipal solid wastes, mixed plastics and tires. Specifically, it involves working with shredded residue waste, which is the plastic and rubber left over from shredded automobiles and appliances.
This mixed waste has a low value, and needs to be separated and prepared. "Those products are going to be a bit different than what you have from animal and agricultural waste," Appel says, describing the challenges associated with this new feedstock. "You're starting with different material and there's a lot more material that doesn't have the value of fertilizer."
When processing municipal solid waste, the leftover material is metal, both ferrous (containing iron) and nonferrous, which go to local metal recyclers. These metals leave the process in the form of oxides, and Appel says they would pass leeching tests to calculate levels of groundwater contaminants. "Nothing is hitting an open flame, and nothing is really going to any extreme temperatures and pressures—nothing that could melt any metals," Appel says. "The only solids that actually break down in the reactor at those temperatures are proteins."
CWT hopes to complete the pilot work by this summer and proceed into design for a commercial demonstration facility that would process up to 200 tons per day. "We're hoping to complete the design for the commercial demonstration plant by next summer and then have that plant operational two years from now," Appel says.
He says the company is working with the county of Los Angeles to site a commercial demonstration facility there. "I would also suspect that there certainly would be interest in putting one in Michigan, due to the presence of the Vehicle Recycling Partnership, which has been cofunding us on the development of the technology for the application of the shredded residue," Appel says. The Vehicle Recycling Partnership involves automobile manufacturers DaimlerChrysler, Ford Motor Co. and General Motors, and is under the United States Council for Automotive Research. It conducts and funds research into recycling various automotive components.
CWT was founded in 1997 to determine a cost-effective way to eliminate waste, with energy production as the secondary goal. "Interestingly enough, the secondary became the primary," Appel says, as the nation became increasingly focused on domestic energy production and decreasing carbon emissions. During this time, Appel says they've "learned an awful lot."
"We still have work to do," he says. "This was a lot more difficult than I thought it was going to be because of all the different factors that come into play, but we've gotten over a lot of different hurdles." One of the highest hurdles to overcome was that virtually everything about this process was new. Early on, adjustments had to be made to fuel delivery systems and other customer requirements. The company also found that it was difficult to train and hire personnel. "We didn't have any analogous-type industry, where we could pull resources from," Appel says. "The training had a lot longer lead time because this all was new."
The biggest issue that the company still has to contend with is waste management. It takes a lot of material to create one barrel of oil. The company estimates that only 10 percent of agricultural waste can be fully converted to oil. With that in mind, the company requires very cheap feedstocks, a lot of storage space and a coproduct that is either valuable or can be disposed of affordably.
Additionally, Appel says the characterization of waste continually changes as recycling technologies and policies change what gets thrown away. "You get surges and spikes of these different shapes, sizes and density of materials, and it becomes an operational issue," he notes. "We had to build in much more flexibility than we had envisioned."
CWT hopes to complete the pilot work by this summer and proceed into design for a commercial demonstration facility that would process up to 200 tons per day. "We're hoping to complete the design for the commercial demonstration plant by next summer and then have that plant operational two years from now," Appel says.
He says the company is working with the county of Los Angeles to site a commercial demonstration facility there. "I would also suspect that there certainly would be interest in putting one in Michigan, due to the presence of the Vehicle Recycling Partnership, which has been cofunding us on the development of the technology for the application of the shredded residue," Appel says. The Vehicle Recycling Partnership involves automobile manufacturers DaimlerChrysler, Ford Motor Co. and General Motors, and is under the United States Council for Automotive Research. It conducts and funds research into recycling various automotive components.
CWT was founded in 1997 to determine a cost-effective way to eliminate waste, with energy production as the secondary goal. "Interestingly enough, the secondary became the primary," Appel says, as the nation became increasingly focused on domestic energy production and decreasing carbon emissions. During this time, Appel says they've "learned an awful lot."
"We still have work to do," he says. "This was a lot more difficult than I thought it was going to be because of all the different factors that come into play, but we've gotten over a lot of different hurdles." One of the highest hurdles to overcome was that virtually everything about this process was new. Early on, adjustments had to be made to fuel delivery systems and other customer requirements. The company also found that it was difficult to train and hire personnel. "We didn't have any analogous-type industry, where we could pull resources from," Appel says. "The training had a lot longer lead time because this all was new."
The biggest issue that the company still has to contend with is waste management. It takes a lot of material to create one barrel of oil. The company estimates that only 10 percent of agricultural waste can be fully converted to oil. With that in mind, the company requires very cheap feedstocks, a lot of storage space and a coproduct that is either valuable or can be disposed of affordably.
Additionally, Appel says the characterization of waste continually changes as recycling technologies and policies change what gets thrown away. "You get surges and spikes of these different shapes, sizes and density of materials, and it becomes an operational issue," he notes. "We had to build in much more flexibility than we had envisioned."
These are problems common throughout the biomass industry. Despite some of the difficulties, Appel is optimistic about the future for his company and confident in the value of his product. Recently, CWT got a boost from legislation that broadened the definition of renewable diesel eligible for tax credits. The legislation also included uses other than transportation. "At the end of the day, it's displacing fossil fuels," he says. "It doesn't matter if it's moving across the road or sits in the basement."
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