Q. How is Max-9® Electrostatic Fabric Filter different from other devices on the market with discharge electrodes mixed with fabric filters?

A. There are other systems that use some sort of discharge electrode intermingled with filters. But the Max-9® Electrostatic Fabric Filter is completely different, and is patented by the EPA. Unlike the Max-9 Electrostatic Fabric Filter, other systems use a form of collecting electrode to capture particulate. This leads to shortcomings:

• The larger particles are collected electrostatically, leaving the small particles to blind or penetrate the filter media.
• Dust loses its charge before it hits the fabric filters, resulting in an agglomerated dustcake and high pressure drop.

The Max-9 Electrostatic Fabric Filter avoids these problems because the charged particles never contact the grounded collecting surfaces, and retain their charge for a much longer period. Therefore, the pressure drop remains low, the particulate is easily removed, and the filters are not blinded or penetrated by fine particulate.

Q. What kinds of filter materials are used?

A. Filter media choice is dependent upon the application. Variables such as temperature, moisture content, and dust chemistry will determine which fabric is best for your particular application. Each Max-9 Electrostatic Fabric Filter installation is site-specific and designed to provide the best possible results and reliability.

Q. Won't sparks from the electrodes catch the filters on fire?

A. No. The Max-9 Electrostatic Fabric Filter operates at very low current densities; power levels are too low to generate sparks, even in heavy dust concentrations. Grounded surfaces are kept far away from the discharge electrodes, while ensuring a very evenly dispersed electrical field. The Max-9 can actually operate without a voltage control, although you'll probably want one or more for data acquisition.

Q. How does the Max-9 Electrostatic Fabric Filter fit in with multi-pollutant strategies?

A. Currently many plants are operating under a certain degree of regulatory uncertainty. However, the Max-9 Electrostatic Fabric Filter fits in well with most combinations of compliance technologies. GE believes that the most likely approach for coal-fired utilities will include SCR or SNCR for NOx control. The existing baghouse or precipitator will be retained for primary particulate removal. There will likely be activated carbon or other agent injected after the precipitator for mercury abatement, probably in conjunction with a wet or semi-dry scrubber for SOx control. The fine particulate created in the scrubber and mercury control module will be collected in the Max-9 Electrostatic Fabric Filter unit, which can also be used to supplement the existing baghouse or precipitator right now, since the efficiency is so much higher. Regardless of what regulations are adopted, Max-9 Electrostatic Fabric Filter provides an extremely high degree of efficiency that will help meet PM 1.0 regulations.

Q. There's no real estate left between my precipitator and the stack. How can I install Max-9 Electrostatic Fabric Filter?

A. The efficiency is so high, and the footprint so small, that almost any plant has room for the Max-9 Electrostatic Fabric Filter modular collectors, especially in a slip-stream configuration. If the goal is to reduce particulate, Max-9 Electrostatic Fabric Filter collectors can be installed in slip-stream, potentially to treat 25% to 40% of the total gas volume. The resultant collectors would take up very little space. For mercury and SOx emissions, a bank of small semi-dry scrubbers can be installed, followed by Max-9 Electrostatic Fabric Filter collectors to treat a portion of the gas stream. They don't have to treat the total gas volume to be effective. GE will assist with plant design analysis to find room for this collector.

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