Evaluation of Process Monitors and Mercury Mitigation Technologies to Reduce Mercury Stack Emissions

Geosyntec evaluated portable, real-time flue gas mercury monitoring options, and then integrated a complete monitoring package into the plant. Geosyntec evaluated portable, real-time flue gas mercury monitoring options, and then integrated a complete monitoring package into the plant.

In preparation for compliance with the US EPA Mercury and Air Toxics Standards (MATS), our utility client needed a robust portable mercury analyzer to accurately quantify elemental and oxidized mercury concentrations in flue gas at multiple locations between the selective catalytic reduction (SCR) unit outlet and the stack. The client wanted the ability to monitor flue gas mercury concentration and speciation to understand how it changed during operating conditions.

In addition, the client wanted to test a number of different mercury mitigation technologies to lower mercury emissions and needed assistance developing, running, and analyzing data from various testing campaigns. To meet these closely related but varied goals, they retained Geosyntec to help them procure the right process monitors for their particular needs and oversee their installation.

Geosyntec’s Scope of Services

Geosyntec’s engineers have direct experience developing, building, and using mercury measurement instruments for power plant applications. Therefore, we were able to efficiently identify and vet third party technologies that were most likely to perform under the particular conditions at our client’s plant. We were also able to modify the equipment by adding the capability to transmit the data wirelessly and the ability to calibrate the equipment remotely. We also showed the client how to use a traditionally permanently-installed monitor as a portable system to test at various locations throughout the flue gas train as needed, rather than buying multiple monitors.

Geosyntec also has experience in testing different mercury mitigation technologies and understands the pros and cons of each. After establishing baseline mercury concentrations at various locations, we helped the client evaluate options including powdered activated carbon (PAC) and non-carbon sorbents, scrubber additives, advanced SCR catalysts to oxidize mercury, and direct chemical addition of halide salts to the coal and boiler to determine the appropriateness of each for their specific needs. We then coordinated trials of selected options, collected gas, liquid and solid samples, and compiled and analyzed the resulting data to help the plant finalize their approach to MATS compliance.

Notable Accomplishments

Geosyntec successfully modified and installed a commercial monitoring system to meet the client’s needs. We also provide ongoing data analysis and monitor support service. We helped the client select the appropriate mercury mitigation technology after accounting for effectiveness, cost, and system reliability. Perhaps most importantly, we helped the client understand the effects that plant operations have on flue gas mercury concentration and speciation and identified opportunities to decrease stack mercury emissions through operational changes. This improved understanding of their plant ultimately reduces the need for additional expensive mitigation additives (PAC, etc.) to meet MATS compliance.

Project Overview

  • Location: Midwest USA
  • Client: Confidential
  • Project Practice Areas: Contaminated Sites, Environmental Management, Air Quality
  • Type of Facility: Coal-Fired Power Plant
  • Services Provided: Mercury Monitor Technology Selection, Stack Testing and Oversight, Engineering Test Program Development and Analysis, Process Optimization for Mercury Mitigation
  • Type of Work: Mercury Mitigation
  • Company: Geosyntec Consultants
  • Governing Regulation: MATS
Geosyntec Consultants
Geosyntec is a consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural resources, and civil infrastructure.

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