Continuous emission measurement | Hydrocarbon engineering
Hot / humid measurement involves analyzing the stack gas sample as is and maintaining sample integrity from extraction to analysis. The main purposes of hot / humid measurement are to prevent condensation of acid mist or water vapor and to keep the compound compositions water soluble. The sample is usually analyzed at a temperature different from the process temperature – this may be warmer or cooler – but the composition of the sample is never changed. It is not necessary to adjust the concentrations reported by the analyzer to account for the water that has been removed when a chiller or chiller is in use.
Let’s focus on a specific metric commonly found in refineries, natural gas processing plants, and steel mills. Measurement of sulfur dioxide (SO2), hydrogen sulfide (H2S), nitrogen dioxide (NO2) and other gases are often reportable gas emissions from Sulfur Recovery Units (SRUs) located at these types of production facilities. Hot / wet analysis is well suited to measuring these gases for the following reasons:
- In dry gas systems, when the water is removed, the components can sometimes be removed selectively. For example, if a sample containing a finite amount of SO2 is cooled below the dew point of water, SO2 dissolves in the aqueous phase reducing SO2 measured in vapor phase. The net result is incorrect measurements.
- The measurement of the sample as is is compatible with the measurement of mass emissions (kg / h of SO2). If the stack gas velocity is measured on an inclusive water basis, the component of interest should also be measured in this manner. The AMETEK 909 and 910 analyzers have the ability to measure mass.
- A Claus SRU incinerator can generate significant amounts of sulfur trioxide (SO3) at high temperatures during disturbance conditions (sulfur entrainment, out of gear, etc.). THEREFORE3 is very corrosive and can damage sample handling systems if the sample is too cooled to the point where SO3 condenses.
- In a hot / humid system, the sample is extracted and aspirated through the analyzer with an air ejector. There is no mechanical pump to maintain.
AMETEK SO2 Analyzers can handle a wide variety of process and sample conditions. AMETEK analyzers have been successfully installed in thousands of sampling locations, for performing measurements in SRUs and other processing units.
To learn more about AMETEK Process Instruments, simply click here.
Read the article online at: https://www.hydrocarbonengineering.com/special-reports/06072021/continuous-emission-measurement/