CASE STUDIES FOR U.S. EPA MERCURY COMPLIANCE FOR POWER & CEMENT PLANTS
Background
In 2012, the EPA estimated that there were approximately 1,350 units affected by MATS in the U.S. The EPA also estimated that the PCA NESHAP rule would affect about 100 Portland cement facilities located in the U.S. and Puerto Rico. The MATS rule created a mercury emission limit of 1.2 lb/TBtu or 0.013 lb/GWh for existing coal fi red units and 4 lb/TBtu for units that burned lignite coal. Cement plants had to meet an even harsher emission limit of 55 pounds per million tons of clinker averaged over 30 days. These plants typically have mercury emissions from both fuel burned and raw materials used to produce the cement clinker. Several years into compliance, 54% of power plants use sorbent traps for mercury compliance monitoring and a little over 40% of cement plants use sorbent traps for NESHAP mercury compliance.
The Clean Air Mercury Rule (CAMR) was fi rst announced by the U.S. Environmental Protection Agency (EPA) in 2005 for
power plants. After much debate, the rule was vacated until the announcement of the Mercury and Air Toxics Standards (MATS) for Coal, Oil, and IGCC power plants as well as the NESHAP
(National Emission Standards for Hazardous Air Pollutants). This was for the Portland Cement Association (PCA) cement kilns under the U.S. Clean Air Act (CAA) of 1990. This case study will focus solely on mercury emissions monitoring because these
regulations place a burden on power plants and cement kilns with stringent emissions monitoring and reporting requirements.
Ohio Lumex Approach
Plants have two options for compliance monitoring with regards to mercury measurement. The fi rst option is the use of a Continuous Emissions Mercury Monitor (CEMM). These analyzers sample continuously and transport stack gas down through a heated umbilical line to the Cold Vapor Atomic Fluorescence (CVAF) or Atomic Absorption analyzer in the instrument shelter. The analyzers measure the mercury concentration in the stack gas in real time. The second option is mercury sorbent trap sampling utilizing EPA reference Method 30B and EPA Performance Specifi cation 12B (PS 12B) for continuous sorbent trap monitoring. Joseph Siperstein, President and CEO of Ohio Lumex, has spent years developing the industry’s most widely used, well respected, and highest quality mercury sorbent traps. These traps are currently used by the majority of power plants, cement plants, and stack testers in the U.S.
Sorbent trap sampling differs from CEMMs in that mercury is absorbed onto a three-section compliance sorbent trap eliminating the transport issues associated with CEMMs. Most in the U.S. have come to realize that the sorbent trap approach yields the most accurate data because it utilizes the EPA reference method. Mercury is collected right in the stack near the end of the probe with no stack gas transport issues.
Case Study 1 Data
The fi rst data set is from an 850 MW coal-fi red power plant burning bituminous coal. This plant uses sorbent traps for mercury compliance monitoring as well as the Ohio Lumex 915J mercury
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