Continuous emissions monitoring system

Continuous Emissions Monitoring. A key aspect of the new CAAA is the requirement that plants prove their continued compHance to new emissions limits by installing continuous emissions monitoring systems (CEMs). The CAAA imposes new requirements for monitoring NO, SO2, and CO2 levels in a plant s exhaust gas stream. Affected plants typically must gather data from stack monitoring systems, gas analyzers, and the plant s data acquisition system and provide the data in a format approved by the EPA and state regulators. CEM systems must be in place by November 1993 for boilers affected by Phase I of the CAAA, and byjanuary 1995 for plants impacted by Phase II. 

The facility may also choose to use an advanced type of monitoring known as continuous emissions monitoring systems (CEMS). CEMS directly measure the pollutants that are exiting the combustion unit stack at all times. If a facility chooses to use a CEMS, they do not need to comply with the operating parameter that would otherwise apply. 

Evolved gases were monitored continuously for 02, C02, NOx, CO, and total hydrocarbons (THC) by a continuous emission monitoring system (CEMS). Batch samples of the offgases were also taken and analyzed for NH3, HCN, residual energetic materials, volatile organic compounds, and N2. The batch samples were collected over the entire duration of each run, and the single value reported represents the average concentration for the whole run. 

Conrad s Centralia plant has no pollution control equipment except for the outside flare for the excess gas. No continuous emissions monitoring systems are used. No local regulations apply to the facility, although an annual inspection is conducted on site by regulatory agencies. 

Small installations in the US SO2 program are generally exempt from the requirement to install a Continuous Emissions Monitoring System and instead report emissions based on fuel use and engineering calculations. 

Installation of continuous emission monitoring systems (CEMS). 

The EPA allows both simple conservative estimation as well as more precise and advanced approaches to emissions estimation. For example, facilities involved in the manufacture of limited products via a continuous process may obtain emission factors from experimental observation (e.g., stack testing) or via continuous emissions monitoring systems (CEMS). 

SCHEME 23.3 Potential culprits for high continuous emission monitoring system (CEMS) readings in ylide reaction. 

In nearly all industrial combustion systems, the fuel flow rate is measured. In many cases it must be measured in order to calculate emissions according to regulatory requirements. For example, some air permits are based on a given maximum fuel flow rate. For some applications that do not have continuous emissions monitoring systems, an emission factor may be assumed using EPA AP-42 [42]. These factors... 

The EPA Method 10 discusses measuring carbon monoxide emissions from stationary sources from continuous samples extracted from an exhaust stack where the sample is measured with nondispersive infrared (NDIR) analyzer. Possible interferences include water, carbon dioxide, and carbon monoxide. Method lOA tells how to make certified carbon monoxide measurements from continuous emission monitoring systems (CEMS) at petroleum refineries. 

The U.S. EPA has developed a series of performance specifications (PS) for continuous emissions monitoring systems (see Figure 7.55) for measuring a wide range of pollutant emissions [43]. These specifications are listed in Table 7.3. Note that two of the specifications (4 and 4A) have identical titles. PS-4 is for the general measurement of CO emissions while PS-4A is for measuring lower concentrations (< 200 ppmv) of CO emissions. These are to be used in conjunction with the EPA methods discussed above. The performance specifications include discussions of calibration procedures and relative accuracy requirements. The EPA has also developed quality assurance procedures to be used for compliance determination [44]. 

Continuous emission monitoring system. (Courtesy of Horiba Instruments, Inc., Irvine, CA.)... 

EPA Performance Specifications for Continuous Emission Monitoring System (40 CFR 60 Appendix B) Specification Specification Title... 

SO2 and NOx continuous emission monitoring systems for stationary sources... 

There are more techniques available on the market for the combustion exhaust composition measurement. For example, the Fourier transform infrared (FTIR) spectroscopy. Continuous emission monitoring system (CEMS) MultiGas 2030 provides real-time, simultaneous measurement of the concentrations of flue gas components ranging from water vapor, nitrogen oxides, sulfur oxides, ElCl, ammonia, H2SO4, and many other compounds. Many organic species can... 

Determination of carbon monoxide emissions in certifying continuous emission monitoring systems at petroleum... 

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