Info box heading Info box text Info box text Info box text Info box text Info box text Info box text Info box text Info box text Info box text Info box text Info box text If


01772 71 4362 Paul.wiggins@environment-agency.gov.uk Charge induction (AC)


Probe electrification Transmissometry Scattered light Notes:


Combination AC & DC Ratiometric opacity Opacity


Scattered light (forward) Scattered light (back)


0.2-2 1-15


2-10 (1) 1-4 (2)


1-4 (1) (2)


(1) Concentration dependant (2) Repeatable flow dependant (3) Application specific


(4) Stack diameter dependant


Table 2: Guide to application suitability for particulate monitoring technologies Measurement technology


you would like further


diameter (m) 0.2-4


Stack on


0.1 1


10 (3) 30 (4)


<0.1 10


informationConcentration (mg/m3) Min


1000 1000 1000 1000


300 (10) 500 (10)


the OMA Max


Filter type scheme Bag, Cyclone


Bag (1), Cyclone, EP, None


EP, None Bag, Cyclone, EP (5) No water droplets


(6) No filter – not advised (7) Model specific


(8) Velocity range 8-20m/sec


The above statements are meant as a guide only and all selections should be made in reconition of the actual application conditions Extractive light scatter and Beta systems are to be used in processes with flue gas below dew point (eg wet collectors)


3 sufficient resolution for the intended application. MCERTS certificates state the certification range in mg/m3 for the instrument which is the lowest dust range at which the instrument will still meet the MCERTS performance standards. The Environment Agency provides guidance on the factor allowed between the instrument certification range and Emission Limit Value (2.5 or 1.5 for low dust applica- tions). The minimum detection level of the instrument should also be considered in relation to the normal operating condition of the plant to ensure a meaningful stable response from the instrument at normal plant conditions which can then be calibrated.


Table 2 above shows the core application areas of the different technologies.


Since instruments are typically used in aggressive stack environ- ments which provide a challenge to an instruments operation and performance, regulators are becoming increasingly focused on ensuring that Quality Assurance (QA) checks are periodically done on instru- ments to ensure they are indeed operating correctly. For particulate monitors it is becoming increasingly common for instruments to have in built mechanisms for self checking so that these checks can be done automatically without the need for direct operator involvement. These Quality Assurance (QA) checks are typically for: n contamination and/ or signal drift at a level equivalent to an elevated dust level (span) n instrument zero stability.


For instruments that are approved under MCERTS these checks must meet the Quality Assurance requirements of the performance standards (e.g. QAL3 for class 1 CEMS, internal reference checks for class 2 and 3 dust and filter leak monitors). These checks not only increase the confidence in emission results from instruments for regulator and plant operator alike but also provide the plant operator confidence that emis- sion levels and incidents are being monitored by a working instrument which is likely to reduce false alarms or incorrect analysis.


Instrument installation


Particulate monitors should always be installed in a location where the measurement volume of the instrument is located in a position which is representative of the particulate in the stack. Since instruments which


please


Bag, Cyclone, Drier, Scrubber (5) None (6)


Certification EU


visit


QAL1 (7) TUV MCERTS


TUV TUV, MCERTS


www.mcerts.net


✓ ✓ ✓ ✓ ✓


QAL1 TUV MCERTS ✓ QAL1 TUV MCERTS ✓


Bag (1), Cyclone, EP QAL1 TUV MCERTS ✓


✗ ✗


Dry Humid Wet or


Hazardous zone Dust


contact Gas


✗ ✓(7) ✗ ✗ ✗


✓ ✗


✓


✗ ✓(9) ✓ ✗


✗ ✓


✓ ✓ ✗


✓ ✓ ✓


(9) Using extractive system with sample heating (10) Must have constant clean air purge supply 24/7


Paul


Velocity dependant


✗ (8) ✓ ✗ ✗


✗ ✗


Wiggins:


Positions to be considered for installation of particulate monitors


report in mg/m3 are calibrated by reference to an isokinetic test and filter leak monitors must just respond to changes in dust, this location does not necessarily exclude locations where the dust concentration is non homogenous across the stack, provided that when the dust concentration levels change in the duct the instrument’s measurement volume is exposed to a proportionate increase in dust.


Both the instrument location and its measurement volume (length and position) should be considered together in a common sense way to ensure representative measurement. Any flue gas homogeneity results from EN-15859 (if performed on the stack) should be considered in relation to the specific needs of the particulate monitor (which are different to gas analysers due to different calibration approaches). Important is to consider if any particle stratification is likely to occur (especially under arrestment plant failure conditions) and ensure that multiple instruments or instruments with longer measurement volumes are used in these cases. In practice the best location for the instrument’s measurement volume of the instrument include: n After the final ID fan where the particles are better mixed in the flue gas


n In areas of straights (4 diameters after bend or disruption and 2 diameters before bend or disruption)


n On the outside of bends (and not in the inside of bends) if plant geometry does not allow for alternative locations


n In the case of Intrusive instruments, not at the same location as the Isokinetic sampling location so as to avoid interference between the sample probes and instruments and visa versa


n In the cases where there is a small measurement volume (e.g. most light scatter instruments and extractive analysers) in a location of fully developed flow


n In the cases where there are multiple feeds to a stack in a position where the instrument will monitor the dust from all sources (i.e. where the flue gas is fully mixed or if this is not possible with a sufficiently large instrument measurement volume, using multiple instruments if necessary)


Instrument calibration/configuration


Ahead of any calibration or instrument configuration it is fundamental measurement practice and increasingly a regulatory requirement that checks are done to ensure the instrument is operating correctly. This


Source Testing Association Annual Guide 2011 11


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44