Bag/ESP hybrid promises cost-effective particulate control

In February 2002 the US Department of Energy/National Energy Technology Laboratories (DOE/NETL) announced the award of funding to support the first full-scale demonstration of W. L. Gore & Associates' Advanced Hybrid Filtration Technology in a coal-fired utility application.

This new air pollution control technology integrates electrostatic precipitation and GORE-TEX Filtration Products technologies to provide a compact, cost effective system with fewer and more reliable components that are capable of greater than 99.99 per cent capture of fine particulates.

The demonstration unit is part of the DOE's Power Plant Improvement Initiative and will be located at Otter Tail Power Company's Big Stone generating site in South Dakota. It has a scheduled start up date of October 2002.

The technology has been tested over several years of development work in the laboratory and with a field pilot unit.

Moving towards commercialisation

Construction of the full size demonstration unit marks the next step towards commercialisation. To accomplish this, Otter Tail Power Company, a strong supporter of innovative technologies and a believer in advancing the quality of air, has agreed to convert its existing electrostatic precipitators (ESPs) at their Big Stone site to the Advanced Hybrid filter design. Primary funding for this conversion will be provided by the US Department of Energy, Otter Tail Power Company and the two other co-owners of the Big Stone site, NorthWestern Public Service and Montana-Dakota Utilities. W. L. Gore & Associates, Inc will also contribute over $1 million dollars in supporting funds.

The geometry of the Advanced Hybrid filter requires fewer components than other comparable air pollution control technologies, claims Gore, allowing the use of higher performance and very durable components.

One such component is the highly efficient and durable GORE-TEX membrane filter bags, which comprise a key part of the overall system and have a major influence on improved overall system performance.

The net result, according to Gore, is superior particulate control at costs comparable to currently used technologies that are much less efficient. The new system is easily adapted to new installations as well as retrofits of existing ESPs.

Looking for sublicensees

This technology was originally patented by the University of North Dakota's Energy & Environmental Research Center (EERC). Gore has been a technical and financial supporter of the technology from the early stages and has been instrumental in developing the concept to its current commercial form.

Gore now owns the worldwide rights to implement and sublicence the technology for industrial applications.

It is Gore's intention to sublicence the technology to a select group of original equipment manufacturers (OEMs) around the world. ELEX AG, a worldwide air pollution control supplier headquartered in Switzerland, has been granted a sublicence to implement the technology and will provide the complete system for the full-scale demonstration at the Big Stone site.