Multiphase Reacting Flow Analysis of Biomass Pyrolysis

Gas turbines are high tech and a significant sunk cost, thus utility companies would prefer to continue to use them for electric power generation even while concerns about climate change grow increasing horrific. With BAU (Business As Usual)*, operators hope to keep coal-fired power plants going by finding incrementally better ways to burn the fuel, letting profit be their God guide to improved efficiency and, oh, by the way, coincidentally reduced emissions, not that it matters, just because we are such good guys.

* Note: BAU-ers can be identified by there use of the term, “clean coal”, when there is no such thing. BAU-ers fiercely oppose a carbon tax since such policy would create a financial disincentive not only to use cheap coal for power but also to convert cheaper coal, tar sands, waste oil, etc. into liquid fuel.

At Lawrence Berkeley Laboratory, Robert Cheng demonstrates the Low Swirl Injector


“The LSI (Low Swirl Injector) works by imparting a slight spin” [Editor's note: Not to be confused with the Syngas Spin] “to the gaseous fuel and air mixture placed in the gas turbine, causing it to spread out. This helps stabilize the flame used to heat the mixture and, more importantly, allows it to burn at lower temperatures. Since the production of NOx is highly temperature-dependent, the lower flame temperature drastically reduces the level of emissions produced. Natural gas-burning turbines equipped with the LSI emitted 2 ppm of NOx, more than 5 times less the amount emitted by conventional burners.”

The recent dirty energy bill endorsed CTL (Coal To Liquid fuel), which is “Worse than Gasoline1” in the interests of “energy security“,* as if such policy logically could be divorced from survival of life as we know it on the planet. Anyway, one step in the same Fischer-Tropsch process that converts coal to Syngas also also works when converting biomass to Syngas. Or, biomass can be added to the slurry.

*Note: To paraphrase Alan Greenspan, I am saddened that it is politically journalistically inconvenient to acknowledge what everyone knows: the Iraq war the 2008 election is largely about coal.

ConocoPhillips, the third largest integrated energy company in the United States, is supporting research at Iowa State University; and, Terry Meyer, an assistant professor of mechanical engineering, received a $87,000 grant “from the Grow Iowa Values Fund, a state economic development program. This grant is supplemented by a contribution of products and engineering expertise from Goodrich Corporation’s Engine Components unit in West Des Moines, a producer of fuel system components for aircraft engines, auxiliary power units, power-generating turbines and home heating systems.”

Terry Meyers


Credit: Photo by Bob Elbert
“Terry Meyer is building the high-speed laser system in the foreground to analyze the performance of combustion systems.”

Science Daily2 describes the research problem:

Let’s say a fuel derived from biomass produces too much soot when it’s burned in a combustion chamber designed for fossil fuels.

How can an engineer find the source of the problem? It originates, after all, in the flame zone of a highly turbulent combustion chamber. That’s not exactly an easy place for an engineer to take measurements.

“It’s fairly obvious when a combustor is not running well and producing a lot of soot and other pollutants,” said Terry Meyer, an assistant professor of mechanical engineering at Iowa State University. “But then how do you solve that problem?

Like other combustion engineers around the country Meyer turned to laser-based sensors that provide data for computer models of what happens in a flaming mix of fuel and air.

Combustion Research at UC-Davis


It took some pretty fancy research to ascertain that a hydrogen charge increases flame speed and combustion stability.

By selecting lasers of different wavelengths, Meyer’s combustion sensors can record where pollutants such as soot, nitric oxide and carbon monoxide are being formed. The sensors can also look for unburned fuel and capture data about fuel sprays, fuel-air mixing and energy release.

Meyer’s lab is now working on a two-year project to develop and advance laser techniques that are expected to help engineers improve the combustion systems that move vehicles, produce power and heat buildings. An important goal of the project is to analyze and improve the performance of alternative fuels in modern combustion systems.

So, is this just more coal-bashing by a greenie-weenie in Upstate NY in January with the temperature at 65F? Mostly. On the other hand, Richard Heinberg is one writer who has focused on energy security and what we will do in response to peak oil and peak natural gas. The situation is very critical. Without oil and natural gas, we don’t have irrigation, tractors, the ability to move food (it is very heavy), and heating for the homes (half use natural gas and about 40% use oil).

Imagine if you will, Wile E. Coyote looking smugly at the Road Runner because he avoided making a dumb mistake, only to be smashed by a stupider, more devastating mistake that he made.

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