Advisory panel tours Luminant power plant units 4 and 5
A mid-May tour of two power plant units allowed Luminant Communit y Adv isor y Panel (LCA P) members and other local residents to see the emission control equipment installed on Luminant’s Power Plant Unit 4 and the circulating fluidized bed (CFB) technology in use at the recently built Unit 5.
The Selective Catalytic Reduction (SCR) device installed over existing emission control equipment in Unit 4 was a very large and noticeable structure whose construction required nearly a third as much steel as that needed to build all of Unit 5. The SCR was still being commissioned at the time of the tour.
Nitrogen oxides (NOx) were being removed before reaching the atmosphere, as intended. Other adjustments to the process were still underway. NOx is the target of reductions because it contributes to ozone formation.
Members heard that the CFB technology originally was designed for use in Scandinavia to burn plentiful but low heat value peat as fuel. CFB keeps the fuel in the system longer and operates at lower temperature, thus reducing emissions. Limestone helps remove emissions coming from the sulfur that is part of coal.
The tour also showed attendees the location of a dry scrubber to remove additional sulfur dioxide and a Selective Non-Catalytic Reduction (SNCR) built into Unit 5. Activated carbon is being used in both units to reduce mercury emissions that come from burning coal. Another obvious feature of Unit 5 was a large cooling tower used to cool process water by evaporation because the lake used for cooling Unit 4 is not large enough to accommodate both units.
In response to questions about the size of the units, attendees heard that the Sandow Station makes enough electricity for about 850,000 homes. Attendees viewed the large power transformer where energy at 138,000 volts is sent into the power grid and made available to retail power providers.
One of the most noticeable aspects of power plant operation was how few employees (6-8) are needed on shift during the off-hours as a result of the highly automated operations. NEXT MEETING
Luminant CAP meets again Monday, Oct. 11. For details, contact the facilitator at 800-484-9212 ext. 4127. Visitors welcome.
Rockdale residents may also contact CAP member John Hughes at 512-947- 3191.