LSR Technologies and its subcontractors designed and installed a 8,500 m3/hr (5,000 acfm) Advanced ElectroCore system and a dry sulfur scrubber to test it using an exhaust gas slipstream at Alabama Power Company's Gaston Steam Plant. Shakedown is scheduled for August 15, 2001. The exhaust gas will be from Unit #4 of a 270 MWe sub-critical, pulverized coal boiler burning a low-sulfur bituminous coal. The Advanced ElectroCore system will consist of a conventional upstream ESP, a dry SO2 scrubber, a particle precharger and an Advanced ElectroCore separator. Particle concentrations and size distributions will be measured at the ESP inlet, at the dry scrubber outlet and at the ElectroCore outlet. The concentration of 12 common HAPs will be measured at these locations as well. For purposes of project organization and monitoring, the work will be divided into nine (9) tasks described below.

Task 1 - Advanced ElectroCore Electrode Evaluation: In the Advanced ElectroCore, an energized central electrode is added along the vertical centerline. LSR will evaluate the new electrode design using an existing ElectroCore unit and modifying it to accept the central electrode. The purpose of this task is to perfect the design for both supporting and electrifying the electrode. The design will be tested with over a period of weeks to determine if there are any problems with fouling or cleanability.

Task 2 - Advanced ElectroCore System Component Design: The second task will be to design the components of the 8,500 m3/hr (5,000 acfm) Advanced ElectroCore system. Since the ESP is already in place, the dry scrubber, precharger and the Advanced ElectroCore will need to be designed.

• Dry Scrubber - The dry scrubber will be a vertical chamber with the gas flowing vertically downward. The diameter will provide a residence time of about 1 second. The top of the scrubber will contain a feeder for dry solid sorbent feed as well as a water injection system to control gas temperature at the outlet. The chamber will be fitted with insulation and clean-out connections.
• Precharger - The precharger will be designed as a conventional dry precharger with weighted wire discharge electrodes. The precharger length and cross-sectional area and the current density will be selected so that the particles will achieve over 90 percent of their saturation charge. As with the dry scrubber, the precharger will be insulated to reduce heat loss that might cause condensation problems since the gas leaving the dry scrubber may be within 15^oC to 30^oC (25^o to 50^oF) of the dew point.
• The Advanced ElectroCore separator will be designed with a capacity of 8,500 m3/hr (5,000 acfm) at a Specific Separating Area of 20 m2/(m3/s) (100 ft2/kacfm). The unit will contain ten 0.4 meter (16 inch) diameter separators that are about 25 feet in height. It will be fitted with flanges for connection to the precharger, to the clean flow outlet duct and the bleed flow recirculation duct. The unit will be thermally insulated to help prevent condensation as described in the precharger design. The unit will be designed with an upper and lower half that can be disconnected to facilitate transport on a flat bed truck. Together with the precharger, this unit will be designed for easy transport and setup as a mobile unit after the completion of this project.

Task 3 - System Construction: The Advanced ElectroCore construction drawings that are created in Task 1, will be released for bidding to local fabrication shops. LSR will oversee the fabrication of the dry scrubber and the connecting ductwork. The precharger will be manufactured by Merrick Environmental and shipped to the field site directly.

Task 4 - System Transport and Installation: The components will be truck-mounted and shipped to Gaston Station on a flatbed truck. At Gaston station, the components will be off-lifted by crane and placed alongside the Unit #4 ESP. Southern Energy Constructors, a local contractor with union labor and an approval contractor of Alabama Power Company, will perform the installation process. LSR will have representation on site to oversee the assembly process and to insure that the installation is performed properly.

Task 5 - System Shakedown: The shakedown tests will be conducted by LSR to ensure that the gas flow rates are within specification and that the power supplies for the precharger and ElectroCore are operating at proper output. Preliminary traverses called for in EPA Method 5 will be performed at the ESP inlet, the dry scrubber outlet, and at ElectroCore outlet. This will ensure that the Method 5 test planes are properly set up and the ducts can be traversed in both planes. The power supplies and control system will be thoroughly checked out. LSR engineers will be perform the shakedown with assistance from Merrick Environmental and Alabama Power personnel.

Task 6 - Field Testing: Field testing will be divided into three subtasks. In the first subtask, efficiency of the ElectroCore system will be measured as a function of gas flow rate and ESP efficiency. The ESP efficiency will be reduced from its maximum by lowering the voltage to its two electrical sections. Gas flow will be changed by varying the speed of the ID fan with an inverter-type variable speed drive. No sorbents will be introduced into the dry scrubber during these baseline tests. Particle concentration will be measured simultaneously at the ESP inlet, dry scrubber outlet, and ElectroCore outlet using three Method 5 sampling trains and high-volume cascade impactors. Due to the large difference in particle concentration between the ESP inlet and ElectroCore outlet (approximately 10,000:1), tests may require several hours to complete at the ElectroCore outlet. To overcome this problem, a high-volume modified Method 5 Sampler developed in France may be used to reduce sample time.

The purpose of the second subtask is to demonstrate that the ElectroCore system can operate with high collection efficiency when sorbents are injected into flue gas stream. The purpose of this test is not to measure sulfur capture and no sulfur measurements will be made. The test is designed solely to demonstrate the ElectroCore efficiency when using dry sorbent injection. Hydrated lime, activated carbon and pressure-hydrated lime-silica will be used as test sorbents in the dry scrubber. The hydrated lime and pressure-hydrated lime-silica will be injected at a rate to produce a calcium to sulfur mole ratio of between 1 and 2. Water will also be injected into the gas stream to reduce the flue gas temperature to within 56^oC (100^oF) to 11^oC (20^oF) of the dew point. The goal will be to demonstrate 99.99 percent system capture efficiency for all primary particulate.

The final subtask will be the measurement of the removal of hazardous air pollutants (HAPs). The HAPs measurements will be conducted simultaneously at the ESP inlet, at the dry scrubber outlet and at the ElectroCore outlet. The concentration of HAPs will be measured at 4 operating conditions with each point being tested twice for repeatability. Two tests will be conducted without sorbent injection, two will be conducted with hydrated lime injection, two will be conducted with pressure-hydrated lime-silica, and two will be conducted with activated carbon injection.

Task 7 - Data Analysis / Cost Analysis: The field test results will provide data to evaluate performance and determine the size of the ElectroCore needed to achieve 99.99% capture efficiency for a given gas flow rate. This information will be used to update the cost analysis data prepared for the conventional ElectroCore in 1996 by Sargent & Lundy, LLC. The update will involve adding the cost of electrodes and power supplies to the separator section and to adjust the flow capacity of the unit. The goal is to show that capital and O&M costs of an ElectroCore system is competitive with the best currently available retrofit technology.

Task 8 - Dismantle Equipment/Site Restoration: The final work to be done at the Alabama Power Company field site is to remove the ElectroCore equipment and restore the test site to its original condition. This involves dissembling the system components and removing them from the site. Ductwork will be removed, and all electrical, water and other services restored.