Extended monitoring requirements for all combustion processes

The stricter monitoring requirements being imposed on European Large Combustion Plants (LCPs), is symptomatic of environmental initiatives affecting a wide variety of industrial sectors. Dr Andrew Dixon from Gasmet Technologies UK (formerly Quantitech) explains how instrumentation companies are responding to these new challenges, using mercury as an example.

The combustion of waste and fuels produces a wide variety of pollutants and greenhouse gases, so regulators are increasingly imposing stricter emissions limits and monitoring requirements to improve air quality and fight climate change.

In general, emission limit values are being lowered, the number of parameters being monitored is increasing, and the requirement for continuous monitoring is growing. Operators are therefore employing multiparameter technologies such as FTIR, or purchasing a number of analysers. However, one of the pollutants of major concern, mercury, necessitates a specific monitoring technology, and since the emissions limits are so low, it is necessary for this technology to have performance certification at these levels.

In Europe, member states have the opportunity to set specific limits and monitoring requirements that fit within the framework established by the Industrial Emissions Directive (IED). So, individual states may set stricter limits, or individual plants may implement more rigorous monitoring and abatement technology in order to demonstrate good environmental performance - as part of a corporate responsibility strategy; in response to demands from stakeholders, or in anticipation of tighter future regulatory requirements.

Mercury is considered by the World Health Organisation to be one of the ten chemicals of major public health concern, so there are global initiatives to lower emissions – particularly from power plants, waste combustion and cement plants.

New environmental standards for LCPs strengthen the requirements of the IED for both reduction and monitoring requirements. These stem from a review of the Best Available Techniques (BAT) Reference Document, the LCP BREF. This includes new BAT-associated emission levels (BAT-AELs) and sets new monitoring requirements for sulphur dioxide, nitrogen oxides, mercury, and particulate matter.

The LCP BREF applies to combustion plants with a total rated thermal input exceeding 50 MW. However, it also applies to smaller units where they are directly related to a combustion plant.

The BAT-AELs for mercury emissions to air from coal and lignite burning power plants are extremely low. For example, a new coal-fired power plant with ≥ 300 MWth has a BAT-AEL of <1-2 μg/Nm³ mercury (yearly average), and an existing lignite-fired power station with a thermal input under 300MW has a BAT-AEL of <1-10 μg/Nm³ mercury.

Monitoring equipment must be MCERTS certified to perform within the requirements of a permit, which is why the possibility of continuous monitoring should be considered, and both current and future requirements for certified monitoring ranges and levels of uncertainty should be addressed. The recent certification of Gasmet’s Continuous Mercury Monitor (CMM) is therefore of particular significance. The Gasmet CMM has successfully completed EN15267-3 testing using CVAF (Cold Vapour Atomic Fluorescence) to provide the world’s lowest EN15267 certified range for measurements of Mercury. The CMM is certified for operation across a number of different ranges up to 1000 µg/m³, but considering the latest regulatory requirements, the CMM’s certified range of 0 to 5 µg/m³ will be of particular relevance to the operators of combustion processes.

In summary, when defining a monitoring strategy it is vitally important to take future requirements into account (from both regulators and stakeholders) when choosing appropriately certified technology.