The answer to “Which Flue Gas Analyser is best?” is simple: it depends.
The type of industry, the application of the analyser, the gas(es) to be analysed, the precision required… all these characteristics will have a direct impact on the assessment of the best flue gas analyser.
Whether in the atmosphere, in industrial processes or in confined spaces, gases are present in a variety of environments and their measurement and analysis is important not only for monitoring air quality, but also for other important aspects such as ensuring compliance with regulations and standards, limiting emissions and reducing negative impacts on health and the environment, controlling and optimising production processes or ensuring safety from hazardous gas exposures.
This is done using instruments known as gas analysers, which can be classified according to a wide range of criteria.
What is a gas analyzer and what is it used for?
A gas analyzer is a device used to measure and analyse the composition of gases present in a sample. These instruments measure the concentrations of different gaseous components such as carbon dioxide (CO2), nitrogen oxides (NOx), sulphur dioxide (SO2), ozone (O3), hydrocarbons and other specific gases depending on the application.
Gas analysers are used in a wide range of applications and industries, including monitoring emissions and controlling processes in chemical plants, ensuring combustion efficiency in the power industry, monitoring the quality of natural gas in the oil industry, controlling the atmosphere in the food industry, or measuring and controlling levels of pollutants in the atmosphere in the environmental industry.
Types of gas analysers according to application and environment
Gas analysers can be classified in different ways and according to different criteria: single gas analysers or multi-gas analysers, depending on the number of gas concentrations they can measure simultaneously, or infrared, ultraviolet-visible (UV-Vis), electrochemical… gas analysers, depending on the operating principle.
But in this case we will make a classification depending on whether the final objective is to monitor the concentration of gases in the ambient air (immission) or in the emission processes so that we can find:
Air quality analyzers
These instruments play a key role in air quality monitoring by measuring and quantifying the concentration of various gases in the atmosphere.
Gas analysers used in air quality monitoring can be either continuous analysers or portable analysers and provide real-time measurements that help to identify sources of pollution, assess compliance with air quality standards and take appropriate action to improve and protect the environment and public health.
Some of the most commonly measured air quality gases are:
- Carbon dioxide (CO2), a greenhouse gas that contributes to global warming.
- Carbon monoxide (CO), produced by the incomplete combustion of fossil fuels.
- Nitrogen oxides (NOx), emitted mainly by the combustion of fossil fuels.
- Sulphur dioxide (SO2), whose measurement is important for assessing air quality near industrial areas.
- Ozone (O3), which is measured to determine photochemical pollution in urban areas.
In addition to gases, the concentration of airborne particles (PM 10 and PM 2.5) is also measured.
These emission analyzers are primarily used to measure and monitor emissions of gaseous pollutants and related parameters from stationary sources such as industrial plants, power stations, boilers and stacks.
Their purpose is to ensure compliance with environmental regulations and to assess the impact of emissions on air quality and the environment.
These analyzers are usually installed at the outlet of emission sources, such as stacks or ducts, and due to environmental regulations they usually have a wider measurement range and higher accuracy and are subject to specific regulations and standards that set allowable limits for emissions.
Industrial emission analyzers measure a wide variety of gases, but the most common are:
- Sulphur dioxide (SO2), emitted mainly from the combustion of fossil fuels containing sulphur, such as coal and oil.
- Nitrogen oxides (NOx), which include nitrous oxide (NO) and nitrogen dioxide (NO2).
- Carbon monoxide (CO), which is measured in gas analysers to monitor combustion efficiency and detect unwanted emissions.
- Volatile Organic Compounds (VOCs), which are easily released from industrial processes and evaporate readily at room temperature, causing adverse health effects.
- Opacity, to determine the presence of particulate matter in smoke or flue gases, usually as a result of incomplete combustion processes. The analyzer used in these cases is called an opacimeter.
Process gas analyzers
Process gas analysers are mainly used to measure and control the composition of gases at different stages and in real time in various industrial processes to ensure product quality, process efficiency and compliance with production standards.
These devices are installed at different points in the industrial process, such as pipelines, reactors, tanks or control equipment to measure the gas composition at different stages of the process, their requirements vary according to the specific needs of the industry and product quality and therefore their measurement range is more limited (as they focus on the gas composition in a specific industrial process).
- Oxygen (O2)
- Carbon dioxide (CO2)
- Carbon monoxide (CO)
- Nitrogen oxides (NOx)
- Sulphur dioxide (SO2)
- Hydrocarbons (VOC)
It is important to note that this is an example of classification and that, as mentioned above, there are other classification criteria such as technology used, measurement range, accuracy, sensitivity… but the choice of the appropriate gas analyser will depend on the specific application and measurement requirements.