Conventional air-emission-control systems attack the problem at the smokestack with filters and scrubbers. ClearSign Combustion Corp. aims its emission-control technology at a much earlier point in the process, where those emissions are first created: at the flame.
The Tukwila company is developing two approaches to reducing pollutants by controlling the flame used in industrial boilers, kilns, furnaces and turbines. One is electrodynamic combustion control (ECC), which uses electromagnetic fields to control the shape of a flame in a boiler, kiln, furnace or turbine. ECC technology has shown reductions in visible particulate matter of more than 90 percent.
The more recent ClearSign development is Duplex, in which a ducted ceramic tile — basically a plate with holes in it — is placed above a standard burner, turning a single large and unruly flame into thousands of tiny, more easily controlled flames and helping to reduce the release of pollutants like nitrogen oxide (NOx).
The benefits of this approach, ClearSign says, include increased heating capacity, more thorough mixing of fuel and air (helping to dilute NOx-forming compounds), extended life of equipment and reduced operating costs.
And it’s no longer just a lab technology. In the California oil fields, ClearSign has been testing Duplex on boilers used to produce steam for enhanced recovery of “heavy” or thicker crude. In May, the company announced a commercial order to retrofit an oilfield boiler.
Incorporated in 2008, ClearSign became publicly held in 2012 — somewhat out of the ordinary for an industrial-equipment firm in development stage.
ClearSign sees a major market opportunity in retrofits of existing industrial equipment, especially for oil and chemical refineries. Increasingly strict federal, state and local environmental rules will likely aid those opportunities. The challenge now is converting them into orders and revenue.