CEM - Abstract

Abstract Information :

As 70% of all mistakes and errors in CEM System are related to the Sample Handling and Conditioning System the trends and developments have direct impact on the developments of the products – again: Only if the both components (probe sampling and analyser) are harmonized and covering the application specific needs and requirements, lower detection limits and a high availability is possible. In the past, experiences about CEM Systems without an accurate and periodic performance testing in China were by many measures reduced and only very limited to be found today. Today even the threshold limit for SO2 in China is at only 35 mg/m3–which infer to the technical implications and consequences for the entire CEM System so including the sampling system and the analyser. Lower Limits: Chance and Risk at the same time The political judgement of losing the pole position on emission monitoring and subsequently emission reduction developing the right technical solutions for this situation represents a challenge – as most of the countries require a local validation of the system and can in these cases no longer rely on the TÜV / MCERT. From the perspective of a probe sampling equipment manufacturer, the risks and rewards are given for every product category. As we all know the measurement process can only produce reliable and accurate results if the Probe Sampling System and the Analyzer are harmonised. New limits also require updates and improvements on the Sample Handling components: From the Sampling, Transportation and Conditioning. Sampling: Special Requirements for Gas Sample Probes Aggressive process applications and technically demanding Industries such as Cement Plants, Steel Plants or certain sampling points in Coal Fire Power Plants the quality of understanding and the focus on Gas Sampling Probes have not been given adequate attention. Due to the fact of low labor costs in merging market and many industries have overlook the initial investment costs (and not the total costs of ownership including the operating costs) as well as short maintenance interval. Next to the reduction of detection limits also higher avalilibility of the CEM measurement itself is required, which consequences into special material selection and e.g. filter surface layout of the Gas Sampling probe as well as intelligent measures for the cleaning of the filter without the need of human interaction. Transport: Heated Sample Lines Until today the transport of the gas probe from the primary probe sampling point to the conditioning system and the analyser is the most underestimated item. Only experts with a long practical experience in commissioning and operating CEM systems will strongly confirm the relevancy of a high quality heated sample line. As in Europe the standard for the holding temperature of heated sample or analyser lines is 180°C to 200°C, other countries such as China often operate on 120°C - which might already be a problem for the acid dew point. The difference between holding a temperature of 120°C and 180°C is enormous – especially as ambient temperatures between up to -20° have to be taken into calculation. All components within the heated sample line have to be designed for this requirement including the process tube and the insulation – furthermore is a heating cable without any side effects and a high power output another crucial partner in the solution layout. Gas Conditioning: Gas Cooling The probably strongest impact on lower limits of all products in the Probe Sampling chain are represented by the Gas Conditioning systems. As sometimes the new limits can not be reached by so called cold extractive systems, hot wet systems are used which can handle the probe without the need of drying it. As the total cost of ownership for these technologies such as FTIR are still higher than the cold extractive systems there are higher requirements for the Gas Cooler: The washout rate of e.g. SO2 has to be reduced, at the same time the outlet dew point representing the remaining water after the cooling process needs to be stable even under changing parameter such as the inlet dew point or humidity of the Gas.