The metals industry is a core focus for PCME’s business, with extensive experience in integrated steel mills, foundries, aluminium smelters and steel mini mills driving the continuous development of monitoring solutions to best meet the demands of industry. Experience gained from over 5,000 applications in the metals industry alone gives PCME a comprehensive understanding of the potential issues facing particulate monitoring for steel mini mills, in particular:
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High temperature flue gases and high ambient temperatures create demanding conditions for both sensors and baghouses, increasing the need for responsive and predictive bagfilter monitoring capability due to environmental stress on bagfilter media
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Harsh and dusty environments require dependable and rugged sensor operation, where reduced sensor maintenance requirements, reduced sensitivity to sensor contamination, and a range of durable sensor options for challenging stack conditions are of significant benefit to plant operators.
PCME offer approved (TUV & MCERTS) systems for particulate measurement, filter leak monitoring and filter performance monitoring, depending on the plant specific requirements which are specified in close consultation between plant operators and PCME. Steel Mini Mill plant typically demands monitoring on multiple emission points across furnace, casting and rolling mill operations, which can be addressed with a networked multichannel system. By offering a range of measurement technologies in reliable and rugged instruments, PCME are able to offer a full range of solutions to meet and often exceed legislative compliance, and significantly improve the operation of filter plant including a reduction in filter maintenance requirements.
As knowledge and awareness increase in the environmental and health concerns associated with metallic particulates, regulators are increasingly focusing on operators of metals plant to enforce lower emissions limits and more strict compliance programs. With a history of establishing, developing and maintaining strong partnerships within the metals industry, PCME bring extensive experience for assisting plant operators to both minimise emissions and improve the operation of filter plant.
Furnace and Casting Shop
Electric arc furnace particulate emissions are produced during charging, melting, refining and tapping, and predominately consist of fine particles of iron oxide, calcium oxide, and other metallic oxides. A variety of emissions capture systems are in use, including forth hole / direct shell evacuation, side draft hood, canopy hood and furnace doghouse enclosures for fugitive emissions. In all systems, exhaust gases containing carbon monoxide are mixed with air and combusted in the exhaust ducting upstream of the filtration plant, resulting in high levels of environmental stress on filter media from aggressive elevated temperatures. This increased wear on filter media increases the probability of filter failure, and therefore the ability to monitor filter performance in real time and predict filter failure before it occurs is of significant benefit to plant operators for reducing costly process interventions and enabling scheduled filter plant maintenance.
Typically these emissions are abated using large multi-compartment bagfilters, and occasionally electrostatic precipitators or wet scrubbers for older plant. PCME offer a range of technologies to maximise performance in the differing conditions found in a variety of abatement plant, and to address the challenging flue gas and ambient conditions found in Steel Mini Mills.
Rolling and Finishing Mill
Oxygen scarfing, rolling and shot blasting operations also produce particulate emissions, although usually at lower concentrations, which must also be controlled. Emissions from scarfing machines are often controlled via electrostatic precipitators or water spray chambers, whereas the particularly abrasive dusts produced during finishing are usually abated with multi-compartment bagfilters. PCME’s range of monitoring systems combined with a consultative approach ensures that the correct technology is applied to the differing process conditions found in Steel Mini Mills.
Sufficient minimum detection level for highly abated emissions:
PCME’s ElectroDynamic™ Probe Electrification technology has a minimum detection level (0.1mg/m3) suitable for highly abated emissions, such as those found after bagfilter plant in Steel Mini Mills, including QAL1 approved instruments with certification range 0-15mg/m3 for Emission Limit Values as low as 10mg/m3. ProScatter™ Forward Scatter instruments such as PCME QAL 181 are suitable for lower concentrations of <0.1mg/m3, and are also certified to the most demanding European (MCERTS and TUV) and US EPA (PS-11) standards. For monitoring emissions after electrostatic precipitators, PCME’s range of DynamicOpacity™ Ratiometric Opacity instruments are also available with TUV performance approvals.
Contamination Detection and Tolerance:
Short Circuit and Contamination Detection
With traditional Probe Electrification type instruments, performance can be compromised by contamination of the sensor probe insulator by conductive particulate matter. Over time, this build up can allow short circuit of the sensor probe via ‘bridging’ of the insulator, which is of particular concern in Steel Mini Mill applications where conductive particulate matter is prevalent. PCME’s ElectroDynamic™ range of instruments includes a patented probe rod contamination check feature, which provides operators with a pre-warning check of possible probe rod short circuit, enabling predictive sensor maintenance scheduling, lower down times and confidence in signal quality (see PCME STACK 990).
Tolerance to Contamination
PCME’s unique and patented ElectroDynamic™ Probe Electrification technology allows sensors to operate normally with significant contamination build-up on the sensor rod, avoiding the signal drift issues associated with traditional probe electrification type instruments and offering greatly reduced maintenance requirements. Additionally, PCME’s patented insulated sensor rod option offers unrivalled performance in high humidity (non-condensing) applications.
DynamicOpacity™ Ratiometric Opacity instruments are often used to replace standard Opacity instruments which require extensive maintenance and servicing time, as they offer the significant advantage of the ratiometric measurement being unaffected by lens contamination. The instruments can provide calibrated measurement with lens contamination exceeding 90%, and are therefore highly reliable with extended maintenance intervals (see PCME STACK 602).
High Temperature Operation:
PCME instruments include medium and high temperature options up to 800°C, to handle the harsh, aggressive temperatures found in Steel Mini Mill applications, particularly after exhaust gas combustion. High grade ceramics combined with heat shields and heat sinks allow the sensors to operate normally and reliably under temperatures far in excess of standard type sensors.
Variable Speed Fans & Flue Gases:
As variable speed fans are common in ducting as part of emissions exhaust systems in Steel Mini Mills, PCME’s ElectroDynamic™ instruments with reduced sensitivity to variations in flue gas velocity provide a significant performance advantage over standard probe electrification type instruments. PCME’s ProScatter™ Light Scatter instruments have no velocity dependence so offer a further option depending on the application conditions.
Network Integration:
Steel Mini Mills typically require instrumentation across several emissions sources. PCME sensors can be networked into one central control unit, integrated with existing plant DCS/SCADA systems, and provide Ethernet connectivity for plant-wide LAN integration.
Quality Assurance:
Stricter compliance programs and more rigidly enforced emission limits within the metals industry mean that operators require an increased level of quality assurance, and confidence in their emissions monitoring systems to operate correctly and also minimise emission limit excursion events. PCME offer systems approved to the latest MCERTS & TUV standards, with manual or automated zero and span / reference drift checks for ongoing quality assurance, and other system self-checks such as short circuit and probe contamination checks to provide confidence in data integrity and to facilitate predictive maintenance scheduling.
