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Show UMESTONE PULVERIZER Figure 3. A possible L E B S configuration in the subsystem down-selection, the potential Impact of the candidate concepts on all other plant subsystems was addressed. Subsystem integration includes issues such as plant efficiency, standardization and modularization, and minimizing cost By investigating the optimum integration of the power plant subsystems prior to the design and construction of the plant, a power plant that is mutually beneficial to all of the major plant subsystems can be developed. The remainder of this paper will cover some examples of the integration issues that were addressed in the B & W L E B S project. SOx/PARTICULATES CONTROL SUBSYSTEM The SOx/Partlculates Subsystem consists of the S 0 2 and particulate matter emissions control systems for the LEBS plant. Candidate S 0 2 control processes considered included pre-combustion coal cleaning processes, various types of sorbent injection processes, and various types of dry and wet scrubbing processes. Other considerations to be addressed were control of hazardous air pollutant emissions (commonly called air toxics) and solid byproduct disposal and/or utilization. The specific emissions goals for the S02/Particu-lates Subsystem were previously stated. Secondary objectives of the S02/Particulates Subsystem are to ensure that: • Any processes selected for application in the LEBS plant have the potential to comply with potential emissions control regulations for targeted air toxics • At a minimum, the selected processes produce an environmentally benign solid by-product for disposal, or recycle in the process (regeneration) or elsewhere (by-product utilization) • The selected processes integrate with other plant subsystems to yield optimal overall performance of the L E B S plant Limestone Injection With Dry Scrubbing (LIDS) The Limestone Injection With Dry Scrubbing (LIDS) process comprises the cost-effective integration of three commercially-proven flue gas clean-up technologies: Furnace limestone injection, dry scrubbing, and fabric filtration. Sulfur dioxide removal occurs in the boiler furnace and convection pass, in the dry scrubber, and in the fabric filter. B&W's LIDS S 0 2 removal technology, shown in Figure 3, begins with the injection of dry. pulverized limestone into the upper furnace cavity. In the furnace, limestone decomposes (calcines) to lime which subsequently reacts with the S 0 2 in the flue gas. Unreacted lime continues through the system and is collected with the fly ash and spent sorbent In a baghouse. A portion of this solid by-product is then recycled to a slaking device where it is mixed with 4 Paper No. 11-13 |