Environmental monitoring: Joined up power plants
1 Nov 2011
The appetite for the development of new waste-to-energy and biomass incineration plants is increasing. At any one time, there can be upwards of 200 such projects at various stages of planning, construction or commission across the UK and it is a number set to increase as waste-related issues continue to dominate future environmental and energy concerns.
The owner/operators of such proposed sites have to comply with a number of tough legislative requirements. In particular, the control, pollutant monitoring and reporting systems employed at the plants must satisfy bodies charged with overseeing the operational and environmental impact of the sector.
Any business generating power from fossil fuels or the incineration of waste is mandated to monitor the gas emissions being produced, as well as to prove to organisations, such as the Environment Agency, that emissions do not exceed the accepted thresholds set down in law.
Currently, plants must meet the specific requirements dependent on the process of three significant pieces of pan-European Union legislation the Waste Incineration Directive, the Large Combustion Plant Directive and the Integrated Pollution Prevention and Control (IPPC) Directive.
Moreover, operators need to meet both their operational and legal objectives on a continual basis, or they will simply not be allowed to go about their daily business.
Disparate structure
Many plant owner/operators, today, require a much more ’joined-up’ approach to their key systems that simplifies the existing disparate structure of control, monitoring and reporting procedures.
This will then help to minimise the business risk of non-compliance in emissions and reporting objectives, and support other areas, such as streamlined and predictive plant-maintenance programmes.
However, the traditional structure adopted by the industry to date has been to utilise three separate systems in an approach to plant control, gas emissions monitoring and legislative reporting.
First, plant-wide distributed process control systems oversee the operation of the plant. Secondly, the continuous emissions monitoring system (CEMS), based upon gas analyser technology, measures the polluting gases produced by the plant. It is configured to satisfy specific European legislation, according to the types of gases produced.
Finally, the reporting system endeavours to take the information from the CEMS system and turn operational data into meaningful reporting for bodies such as the Environment Agency.
These three systems each have their own software platforms, operational issues and maintenance requirements, but lack any capability to communicate with each other in a collective, holistic manner.
Such structures have been widely adopted due to the lack of a single platform to accommodate the disparate nature of each individual system. However, technology has advanced to a point where it is now possible for a single hardware platform to run an overall process control operation linked to CEMS, which is linked to the final reporting requirements.
Risk reduction
Operators will, thereby, have a single system instead of three, which in turn offers increased operational efficiency through easier maintenance strategies and a greater visibility for operators across their plant operations.
This, by association, delivers business-risk reduction in the key areas of emissions monitoring and reporting, so that all legislative obligations can be better met.
Owners/operators of waste-to-energy and biomass plants already have to employ MCERTS-compliant gas analyser technology, as part of the monitoring process. MCERTS-approved reporting, while not yet compulsory under law, could well become so in the future.
Such legislation would significantly increase the importance of employing a single hardware and software system that, as well as providing overall plant control, also delivers both monitoring and reporting functionality to meet current and future MCERTS requirements.
With incineration of waste or biomass comes major responsibilities in terms of effective pollutant-gas monitoring and reporting of activities activities that have to be conducted under an increasingly searching legislative spotlight.
An integrated technology approach can bind together the different systems that currently co-exist on site. This offers an opportunity for plant designers and operators to minimise the risks and challenges presented by increasing regulatory pressures in the area of emissions management.
Bob Lane is business manager, sensors & communication at Siemens Industry Automation & Drive Technologies
GHG analysis out in the cold
PhD researcher Martin Brummell from the University of Saskatchewan has employed FTIR analysis technology to monitor greenhouse gases (GHGs) in the High Arctic of Canada.
Huge quantities of these gases exist within Arctic ice and frozen soils, so understanding the relationship between GHGs in the atmosphere and in the ice/soil. This is seen as vital because melting of permafrost could cause a climate-change tipping point.
For a study on Ellesmere Island in the Canada’s Baffin Region, Brummell employed an FTIR device a Gasmet DX4015 from Quantitech to monitor the production, consumption and atmospheric exchange of CO2, methane and nitrous oxide (N2O) gases which are released and up-taken by soil microbes in the Arctic.
“The real-time nature of the Gasmet FTIR, allowed me to see results within minutes of setting up in the field. This permited me to make changes to the experimental design and further investigate unexpected results whilst in the field,” said Brummell.
FTIR contrasts with traditional methods of soil gas analysis, which employ lab-based gas chromatography systems and collection of samples ’blind’ in the field’, the researcher noted.
The FTIR device was used to examine both the flux of gases from the soil surface and the concentration profiles of gases in the soil’s active layer above the permafrost: the unit providing raw data consisting of gas concentrations in parts-per-million.
Surprisingly, the work revealed areas of strong CO2 and CH4 production immediately above the permafrost. Brummell believed this was the result of the relative disparity in carbon distribution in Arctic soils in comparison with warmer climes.
Carbon accumulates far lower in Arctic soils due to the constant mixing and burying of organic matter, which fuels microbial activity at a deeper level. Comparing the surface flux and the soil profile for each of the GHGs was therefore a key part of Brummell’s work.
Interestingly, Brummell observed a negative surface flux for NO2, but no significant regions of consumption were identified. The location of the NO2 sink is not yet clear, nor the organisms and biogeochemical processes responsible.
