Continuous Opacity Monitoring System (COMS): The new focus on environmental protection


Continuous Opacity Monitoring System (COMS): The new focus on environmental protection

Although the switch to alternative energy is clearly in evidence, coal is still used in steel production, power generation, and a myriad of other industries, and it is likely to remain the main source for these applications in the foreseeable future. With a public perception of environmental abuse and the misuse of fossil fuels it’s important to note that US plants are legally obliged to measure and report the performance of their stationary sources and prove that their stack emissions are within EPA mandated permit limits. One way to do this is with the use of an opacity monitoring system.

Opacity monitor as a reliable emission measurement instrument

One measure of poor combustion is excess smoke emanating from a smokestack.  A well-tuned combustion process (the perfect mixture of fuel and air) emits a clean clear smoke that cannot be seen by the human eye.  Using instruments that can measure the presence of smoke allows for sources as well as regulatory agencies to monitor the concentration of particulate matters (which makes up smoke) in the stack and determine if plants are operating within their prescribed limits.  Opacity is the measure of the obfuscation of light.  A pure black smoke that approaches 100% opacity, a clear transparent smoke is closer to 0% opacity (the human eye cannot ascertain opacity below 3-4%).

COMS (Continuous Opacity Monitoring Systems) uses light to determine opacity levels.  A light shone across a stack bounces off a mirror on the other side and returns to be measured.  How much light went out versus how much came back is used to calculate the % opacity value.

Using this system a plant can calculate the accurate opacity percentage and make sure all EPA regulations are met (a typical opacity limit is no greater than 20%).

Continuous opacity monitors are typically used by facilities which rely on waste materials, oil, coal, wood or other fossil fuels for combustion. Natural gas combustion sources don’t measure opacity as the burning of natural gas does not produce smoke.

EPA requirements for opacity monitor measurements

  • The opacity of stack gases must be monitored and measured in percentage. Keep in mind that transparent emissions are recorded as having 0% in opacity while those which block light completely are 100% opaque.
  • Continuous opacity monitoring systems must be operated at all times (except for maintenance periods, checks, and other activities related to quality assurance).
  • Any monitoring system must be adequately calibrated to meet site-specific requirements and make sure readings will be obtained accurately.
  • Emission measurement equipment is to be regularly checked for calibration errors, fault indicators, poor performance, displacement of optical components, response difference, and other failures affecting the accuracy of data acquisition.
  • Plant operators are required to provide performance reports and emission opacity results on a quarterly basis.

Other reasons to install an opacity monitoring system?

Besides monitoring opacity for compliance, opacity monitoring it can also serve many other purposes, including:

  • Process monitoring and performance indicator of other equipment installed on your site;
  • Tuning tool for combustion equipment
  • Public relations tool to show your deep concern for the environment.

You can have it all with our continuous opacity monitors

Monitoring Solutions offers a wide range of opacity monitoring systems to help customers meet regulatory compliance and/or process control requirements.  We have supplied 100’s of systems across the United States and offer a complete array of services including application engineering, start-up and installation assistance, certification services, and ongoing maintenance and testing.

Our line-up includes:

  • CODEL EnergyTech 101/102. Perfectly suited for those mon-compliant applications.
  • DURAG D-R 290. One of the most reliable, easy to use, and simple to maintain opacity systems on the market today.  Perfect for all compliance applications.  The D-R 290 features no-drift technology and never requires zero or span calibration.
  • COMDAS Evolution. Complete your package with a Data Acquisition System designed specifically to meet the recording and reporting requirements of an opacity monitoring system.

At Monitoring Solutions, we have the next-generation opacity and data acquisition equipment you need to insure your plant meets and exceeds its monitoring requirements.




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