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Staying on the right side of the law

Published by , Senior Editor
Hydrocarbon Engineering,

The preservation of the environment is an aim that concerns everyone and industrial companies are, of course, not immune from these concerns. Thus, either from their own free will or due to legal requirements, more and more companies from a range of different sectors are installing Continuous Emissions Monitoring Systems (CEMS) at their productions sites to monitor and control their emissions. What are CEMS devices really for?

As in any field, information is key to deciding the answer to this question in the most intelligent and accurate way. Having reliable and up-to-date information on the pollutants created by an activity makes it possible to face these problems with agile and adapted responses and to prove that legally required limits are being met. These systems measure the components that the client selects; these are typically volatile organic compounds (VOCs), carbon monoxide (CO) – when there is combustion – nitric oxide (NOX), sulfur dioxide (SO2) – in the case of incineration – metals, or acids such as hydrochloric acid (HCL) or hydrogen fluoride (HF).

A CEMS can apply to any instrument that is measuring some of the various constituents of an exhaust gas on a continuous basis. Environmental technology, of which CEMS are an example of, is becoming paramount and common for all sectors. By way of example, according to research carried out by Markets and Markets in 2019, it is estimated that in 2019 environmental technology had a value of almost US$9 billion. It is also estimated that in 2024 it will have more than tripled in size to represent a value of US$30 billion. According to the report, the compound annual growth rate (CAGR) will be almost 30% over the next four years.1 The environmental sector would seem to be the sector with the best future prospects and, despite COVID-19, projections remain positive.

Figure 1. It is increasingly common in the European Union for polluting emissions data to be received by an external server.

On many occasions the implementation of these systems is due to requirements from administrations that are seeking to ensure compliance with environmental regulations. For that matter, it is increasingly common in the European Union (EU) for polluting emissions data to be received by an external server that belongs to the relevant administration, which can be either the ministry concerned with environmental affairs or the environmental departments of the different local or regional administrations. This form of monitoring is increasingly common in Spain, for instance, and in the rest of the EU member states. From the professional perspective of an environmental technology company, it can be said that these systems already work effectively in projects of all kinds, e.g. airports, highways, waste incineration plants, etc.

Unlike other forms of pollution that are obviously visible, such as landfills or wastewater, the fact that air pollution is, for the most part, invisible generates difficulties for public administrators. In addition, the area of pollution can depend on factors as random as weather, wind direction, rainfall, etc. Consequently, it is often the case that the area that receives the harmful effects of pollution is not the emitting area. In this sense, the responsible companies are even more susceptible to potential suspicion from legislators. Thus, the monitoring and control of emissions is a trend that is more than evident today and without doubt will be a legal imperative in the majority of already industrialised countries. Another option, in terms of what legislators can mandate, is for the polluting company to send measurements on a regular basis from, for example, its combustion chambers. With this specific data, an assessment of the pollution is carried out. However, without a CEMS, this data will always be inaccurate and the administration concerned that watches over environmental regulations will be aware that this data can be manipulated.

Likewise, the authorities in charge of ensuring a healthy environment within their countries will always prefer receiving the data constantly over carrying out inspections, since these require professional personnel and only give the required information for a few specific days.

The benefits for an industrial company of installing monitoring systems at their production sites are numerous: control of legal emissions according to regulations; control of variables such as humidity, temperature, pressure, or type of pollutant; evaluation of the operation of the equipment during the production process; quantification of the amount of raw material lost in operational processes and in transportation; adaptation and improvement of the systems, daily verification, preventive maintenance, etc. All those advantages and sources of knowledge allow the company to improve its production processes, protect its systems, and have a cumulative display value of the amount of emissions in order to eliminate polluting particles.

Figure 2. The benefits for an industrial company of installing monitoring systems at their production sites are numerous.

These benefits are in addition to others, such as the anticipation of inevitable legislative changes – which are becoming stricter across the world – as well as good management of corporate social responsibility in an industrial sector still closely associated with bad practices that generate too much pollution.

What type of information must a CEMS provide?

A CEMS usually has rack analysers, a multi-component analysing system, a flow meter, and management software and hardware.

A CEMS should give an immediate alert if there is a failure in the baghouse filter, the dust collector, or if there is an obstruction in the piping of the pneumatic transport system. It should also deliver alerts in the presence of high levels of particle concentration in a work area, as well as provide accurate readings of particle emission directly in mg/Nm3. Finally, a CEMS should be capable of recording readings in various formats: ‘online’ or averaged every 15 minutes, half an hour or other timeframes, depending on requirements.

The information provided by the equipment must be reliable and in real-time, and is even more valuable if the report is issued through software directly to the PC. In addition, the CEMS equipment must be easy to operate and not affected by variables such as humidity, temperature and pressure. It is very important that the software has the ability to send the data to the central administration in the same code and language in order not to interfere with communication.

A successful example of the application of particulate monitoring is in baghouse filter systems. In this type of equipment, particle detectors are ideal for providing information on the operation and performance of the emission retention system itself. This type of monitoring equipment is very important when installed just after the filter system. In this case it is possible to reduce operating costs and minimise emissions into the atmosphere.

In the case of baghouse filter systems, the most common monitoring systems are baghouse burst detectors, which can monitor changes in emissions and provide a valuable tool for minimising process emissions and monitoring plant malfunctions.

In addition to baghouse burst detectors, it should be noted that filter performance monitors are also important. They provide the ability to detect leaks and, as more advanced instruments, have the ability to monitor the dynamic operation of the filter cleaning system and diagnose the location of faulty rows and compartments. In this case, valuable information is provided for those responsible for maintenance and therefore the costs of replacement of the baghouse filters can be reduced.

Likewise, one of the most relevant advantages of having a CEMS is that it also measures the efficiency of key processes. This is applicable, for example, to making a boiler combustion process more efficient, determining safety in electrostatic systems, or to balancing the energy supply of a cogeneration installation.

Other monitoring systems

The acronym PEMS stands for Predictive Emission Monitoring System and designates software analysers able to provide a reliable and real-time estimation of emission properties by means of a model, using process values (temperature, flow, pressure) as input variables.

Another example of control and monitoring is the flame ionisation detector (FID). This detector analyses the total organic carbon (TOC) content online in the stack to verify that it complies with UNE-EN 14181 and UNE-EN 15267 standards for automatic measurement systems.


The management team of an industrial company that generates pollutants during its operation processes, no matter how few, have to control and monitor emissions if they want to be committed and in step with society. A 21st century industrial company must avoid causing suspicion and mistrust of its emission practices at all costs and pursue transparency to become environmentally-friendly and socially responsible.


  1. MarketsandMarkets, ‘Market Leadership - Green Technology and Sustainability Market’,,27.1%25%20during%20the%20forecast%20period

Written by Bernat Sala, Tecam Group, Spain.

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