A Solid Approach to MSW Fuel

The concept of solidifying preprocessed municipal solid waste into fuel pellets or briquettes is not new, but the market has been slow to mature. 

Fuel Familiarity 
WastAway began processing MSW in 2003, at its commercial facility in Warren County, Tennessee, using a patented process to create a product called Fluff. According to Terry Moore, chief business development officer with WastAway, the material that comes out of the process is basically free of metals and most of the inert materials, including ash from glass, rocks and dirt. Trash is first shredded, then the metals and inert material extracted, leaving the organic portion of the MSW. “Those things are shredded again, and they go through the hydrolyzer, which is a continuous-flow autoclave that runs at a higher temperature and pressure than an autoclave for sterilizing surgical instruments,” Moore says. “The reason we do that is to kill anything that is in the waste, any kind of pathogen.”

Around 2009, the company fired up its commercial facility in Morrison to pelletize its Fluff product, after the idea was suggested by WastAway shareholder Battelle Institute, an applied science and technology development company. Densifying aided with gasification, but the genesis of the move was for easier and cheaper shipping and handling. “It has the same Btu value whether it is pelletized or not, it is just a matter of whether the plant is close enough,” Moore says. “If you have to ship it a long distance, Fluff is maybe 15 pounds per cubic foot, and pellets are 35 or 40 pounds per cubic foot, so you get more pellets on a truck, and you still pay the same amount for freight.”

Since then, the company has tested the product with engineering companies and labs. According to Moore, the product is “amazingly consistent,” usually about 8,700 Btu per pound, varying between 8,500 and 8,900 Btu per pound. The material has been tested to the European CEN/TS standard. According to Moore, the scaling system is rated one to five in three different categories—Btu value, chlorine content and heavy metals. The poorest score being all fives, Moore says WastAway’s fuel generally qualifies as two-two-one. 

 Last year, WastAway completed testing in Canada, the purpose of which was for Canadian power companies to determine whether the fuel behaved similarly to coal. “They found that it does, that the ash that’s generated from combusting this material is a little bit improved from the ash that you would get from coal,” Moore says. “They were also shown that it completely combusts in the firing zone—there are not any residual, noncombusted parts—and that it pulverizes just like coal will pulverize for a pulverized coal boiler.” 

The testing results sparked interest in some Canadian provinces where CO2 emissions are very stringent, Moore adds. “If they burn 5 to 10 percent blend of our material with coal, they could get enough carbon credits to lower below the emission levels so they can continue to operate these large, electrical facilities,” he says. 

Depending upon the location of a community or company, WastAway pellets may qualify for carbon credits, greenhouse gas (GHG) credits, renewable energy credits, recycling credits, landfill diversion credits and renewable portfolio standards certificates. Other sources of revenue can include tipping fees, ferrous and nonferrous metal sales, glass and inert sales and Fluff or WastAway pellet sales. “We look at all of the garbage that comes out of the back of the garbage truck as having value—we want to get all but the oink out of the pig—so we are looking at recovering everything there is,” Moore says.

Besides cement kilns and pulverized coal boilers, gasification is another outlet the company is marketing to, for creation of power, biofuel or chemicals. 

Moore says companies that operate on coal usually value Wast-Away pellets on a relative Btu basis with coal. “If you had 11,000 Btu of coal selling at $60 a ton, you would probably see our pellets selling at $40 or $45 a ton,” Moore says. “It just depends on the value of the coal and the price they’re paying for that coal, as to what the customer will be willing to pay for the pellet.”

Although WastAway has been actively marketing the process to sell the equipment and license the technology, the company has just two commercial operations—the one in Warren County and one on the island of Aruba. “We don’t have any other plants at this time, but I can tell you if we talk this time next year, there will probably be five to 10 sales that we have completed,” Moore says. “We’re always looking for places that can support the process, both from a raw material standpoint and as a user for the output.”

One example is a project at Drayton Valley’s municipal landfill in Alberta, Canada, where testing will resume. According to Moore, the project was held up when a power company suspended testing the pellets in a pulverized coal boiler due to economic issues, particularly what the carbon credits would be valued at.

All in all, emerging projects demonstrate RDF potential, and those involved believe it can compete with other fuels in the market. NBWS and WastAway claim their products have a better shelf life than wood pellets. “The pellets that we make, because there is no active microorganisms in them, have a shelf life that is infinite,” Moore says.

These companies also say their products are odor free, and are on par with the consistency of coal or wood pellets.

For now, however, the market is much narrower for RDF. Players in the space agree RDF use will expand, but only commercially—not on the residential side. “Inherent in garbage are some things that you would need a more sophisticated emission control system for than what you would find in a household stove,” Moore says. “When you burn wood you just get CO2 and water for the most part, maybe some VOCs, but with burning garbage you get lots of stuff.”

Moore adds, “I think it will be a game changer, but the first rule of a manager is to maximize shareholder wealth, so the idea here is we want to make some money so our investors are repaid for their patience and the risk they’ve taken.”

Read the full article here.

By Katie Fletcher | Originally published by Biomass Magazine.