A Short Story on Pellet Plant Innovation

By Anna Simet | April 04, 2014

So a little bit more on the Pellet Supply Chain Summit held a couple of weeks ago in Orlando, in order to fulfill my promise in last week's post.

One presentation that I really enjoyed—though they all were great—was given by Malcom Swanson of Astec Industries Inc. He discussed modular pellet plants, how Astec founds its way into the business, and the company’s method of building these facilities.

Astec began its journey into the industry by constructing a prototype plant at its headquarters in Chattanooga, Tenn., which served as a research and development facility, but was still composed of large pieces of equipment, most of which were manufactured by existing Astec companies. This way, the company could acquire the operating and building experience it needed to construct plants of the size most developers desire today.

A major element of Astec’s plant, and the difference from the typical pellet plant, is that they don’t use traditional air-swept rotary dryers, Swanson explained. Rather, they use hot oil tube dryers. Using this method, chips are dried in a nearly oxygen-free environment. Hot oil runs from a Heatec Convectec—an Astec company—through a rotary dryer to produce heat, so there’s very little risk of fires or explosion.

In addition, offgasses from the drying process are conveyed to the combustion chamber of the hot oil heater where they are destroyed, so large plants can operate without regenerative thermal oxidizers (which destroy  volatile organic compounds with high temperature combustion), Swanson said.

A huge benefit of Astec’s modular plant design is that nearly all components arrive on site assembled and ready to drop into operating position. That is, with the exception of the hot oil tube dryer, Swanson said. The tubes inside are left out and must be placed onsite, because fully assembled, it weighs a whopping 300,000 pounds, and is not highway transportable.

Astec built its first commercial-scale facility Hazelhurst, Ga., for Fram Renewables, a 551,000-metric ton plant. Assembly began in July 2013, according to Swanson, and pellet production was anticipated to begin by the end of March.

 Astec’s story is just one of many industry innovations we heard about at the summit. Lots more to share in coming issues of Biomass Magazine.

I’m looking forward to hearing even more innovation stories at the Northeast Biomass Heating Expo in Portland, Maine, next week. I’m going to kick off the conference by attending the boiler bus tour being offered, which will stop at three schools, a court house, a lumber manufacturing facility and a boiler assembly/pellet redistribution facility, all which use either pellets or wood chips for heat.

Hope to see you there.