News Release

Testing Completed for Ammonia Continuous Emission Monitors at Power Plants

Release date: 05/04/2004

Contact: Jane Ice (513) 569-7311

FOR IMMEDIATE RELEASE

CINCINNATI (May 4, 2004) – The U.S. EPA’s Environmental Technology Verification (ETV) Program, in cooperation with Battelle, recently completed performance verification tests for two continuous emission monitors (CEMs) for ammonia (NH3).

The ETV test verified the performance of commercial ammonia CEMs by challenging them with ammonia standard gases under normal operating conditions in a full-scale, coal-fired power plant equipped with selective catalytic reduction nitrogen oxide (NOx) control technology. The performance parameters included accuracy, linearity, precision, calibration drift, zero drift, response time, ease of use, and completeness.

CEM technology detects ammonia “slip” emissions at many types of industrial facilities, including power plants. CEMs produced by Opsis, Inc., and Siemens Laser Analytics were tested at the American Electric Power’s Mountaineer Plant in New Haven, WV. The Electric Power Research Institute also contributed to the project.

Ammonia “slip” refers to the amount of unreacted ammonia that may escape into the atmosphere from a NOx reduction catalyst. NH3 is a colorless gas, and is reactive and corrosive. Its pungent odor is noticeable above 50 parts per million. Emissions of ammonia gas can irritate the eyes, nose, and throat in small amounts and can be poisonous if inhaled. Ammonia can also be explosive when mixed with air in certain proportions.

Ammonia gas is emitted into the atmosphere by many types of industries, including coal- and gas-fired plants. Since 1996, environmental agencies in northeastern states have included ammonia emission limits when issuing air pollution permits.

Monitoring devices provide real-time, continuous measurements that can help maintain ammonia slip at acceptable levels while not interrupting high NOx removal efficiencies. Power plants employing process control technologies benefit by saving on material costs.

In addition, CEMs allow remote monitoring of NH3 levels and they avoid the need for labor-intensive stack sampling methods that require post-sampling laboratory analysis. Such analysis typically requires one to three weeks to report results to the plant.

ETV is a public-private partnership that provides quality-assured, peer-reviewed test data about the performance of new environmental technologies. The information is used by purchasers and regulators in their decisions to select innovative environmental technology. More than 260 technologies have been verified across a wide spectrum of environmental science and engineering categories.

EPA also relies on this quality science as the basis for sound policy and decision making.

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