HTI installs biomass-powered turbine at Michigan feed mill

By Anna Austin
Heat Transfer International has nearly completed the installation of a biomass energy plant at a feed mill in Howard City, Mich., that will become the state's first gasification plant and the world's first hot air turbine powered by biomass, according to Pat Dickinson, HTI business developer.

The plant will convert turkey litter at Sietsema Farm Feeds into a syngas that will be used to provide the heat and electricity needed to produce turkey feed.

HTI is a designer and manufacturer of starved-air/low-temperature (SALT) biomass gasification systems, Dickinson said. "We have a technology that converts biomass, through a thermal process, into synthesis gas," he said. "The syngas is sent to a chamber where it is combusted-much like natural gas or propane-and is then used to make heat, which can be converted into steam, power or hot water; any commodity that is desired."

Dickinson said the unique aspect of the soon-to-be commissioned system at Sietsema Farm is that the air turbine will produce power from poultry litter without the use of steam or an internal combustion engine. "We don't have to worry about trying to clean the gas to run it through a reciprocating engine," he said. "The heat we produce off the gasification process is sent through our patented high-temperature ceramic heat exchanger technology, which sends clean, hot air to the turbine. So many times people are looking for-especially for smaller power systems-a half megawatt or a megawatt of power. If they want to make power, they have to make high-pressure steam and use a steam turbine. We don't have to go through that process, or have a high-pressure boiler to make power."

The system at Sietsema Farm is capable of handling 35 tons, of turkey litter per day, although this type of system uses a fixed-bed gasifier and can handle nearly any type of biomass, as long as size and moisture content are previously configured. "It isn't limited to dry biomass," Dickinson said. "The type of gasifier that we're building right now can handle anywhere from zero to 50 percent moisture, so it has flexibility. We make three or four different styles of gasifiers so we can cater to the particular kind of biomass that will be used."

As for quantifying its biomass processing capabilities, HTI's systems are modular designs, so the number isn't definitive or restricted. "This particular system (Sietsema Farm) is handling 35 tons per day, and it's a 23 million Btu per hour system. If you need 50 million Btus per hour or 70 tons per day, we'd build a larger system or two systems."

The system installation at Sietsema Farm may be HTI's debut, but Dickinson said the company's technology is based on decades of experience. "We purchased the assets, patents and technology from our senior application engineer Robert Graham, who has been doing this for over 50 years-designing gasification systems-so he brings previous experience, knowledge and all of his work on previous jobs," he said.

Design work on the Sietsema Farm system began in the spring of 2008. Dickinson said winter weather delayed the schedule, but construction resumed at the beginning of April; installation began early June. Now more than 90 percent complete, the companies expect to officially open the facility at the end of October.

When calculating the return on investment (ROI), Dickinson said it's difficult and may vary considerably depending on the size of the plant, feedstock costs and other variables. "It's hard to compute," he said. "Typically, a small plant may have a longer ROI because there are more capital costs versus building a larger plant where you're spreading the costs over a lot more power and a lot more steam. What's your feedstock? Is it free or are you paying for it? Are you getting a tipping fee for it? Do you need power or steam? Are you going to sell your power as green power in certain states and get very high revenue for it and buy back your power at your lower retail rates? Are you going to apply for investment tax credits through the government? Are you going to use treasury grants to build the plant?"

Dickinson pointed out that HTI's systems are utility-grade power plants designed to last 25-plus years, and aren't necessarily built for a quick ROI but for long-term money savings, or protection against fluctuating electricity and natural gas prices. "At Sietsema, [David Prouty] owns a turkey farm, he's a pig producer, and he has a feed mill where he manufactures all of his own grain for his pig and turkey operations," he said. "This energy center isn't at the poultry facility but at the feed mill where he needs power and steam. He's doing it for the long term, and will be able to control his own expenses at the feed mill without having to worry about the fluctuation and prices of electricity and natural gas."