Air Monitoring 41


Metrology Programme for Innovation and Research (EMPIR) project ‘Sulf-Norm’ is aimed at addressing some of the issues. Work is being undertaken in this project to better understand the


performance of different conditioning technologies at low SO2 levels applicable to a range of different industrial processes. As a starting point for the project a survey was carried out to exploit the experience the community has to date with conditioned (portable instruments) and unconditioned (SRM) sampling in order to gauge current perception of capability. Here we summarise the results of this survey and discuss the reported experiences, providing trends where possible.


Survey Respondents


This survey was made available online and hosted through the Source Testing Association (STA) servers, with the aim of being available to a range of organisations and relevant parties across Europe. A link was circulated to the STA membership and also by Sulf-Norm project partners to members of the emissions monitoring community within their respective nations, and in some cases beyond. A total of 57 questionnaires were completed online with the highest numbers of participation from Germany, Italy and the UK (Figure 1).


Figure 3: Method Offered by Country (% Respondents)


Much of this divide might be explained by the approaches of the national regulators in each country. For example, in the UK, Finland and other Scandinavian countries, alternative methods (AMs), such as those based on portable instrumental techniques, tend to be accepted by the national regulators whereas this generally is not the case in Germany and Italy where only the use of the SRM is permitted for regulatory purposes.


To gain an insight into the methods being used in the field, survey participants were asked to list the types of process plants on which they sample SO2


, and the types of testing they commonly


undertake in these circumstances (i.e. compliance and QAL2 calibrations). These EN 14181 QAL2 calibrations are carried out after the installation of an AMS, taking parallel measurements and testing the range of validity of the calibration functions in order to ensure continued suitable operation. Under the Medium Combustion Plant Directive periodic measurement is required on small to medium combustion plants at least every three years (1MW-20MW thermal input), or every year (>20MW), but certain member states may require continuous measurement by means of AMSs4


A broad range of institutions took part, with full-time staff numbers ranging from 10s to 1000s. The breakdown in Figure 2 shows that the majority of organisations who responded were independent test houses (65%). National regulators and in- company test houses also responded in high numbers, with other participants ranging from instrument manufacturers to energy producers.


Figure 5: Large Combustion Plant SO2 Monitoring (Number of respondents) E: EN 14791, P: Portable Techniques, B: Both


Respondents were asked which monitoring methods they would rather use if they had a free choice in the absence of any regulatory requirements. 59% of respondents selected portable techniques, with 24% preferring the SRM and 17% with no opinion. It was postulated that perhaps those without an in- house capability for analysing collected sulphate samples would inevitably have a preference for portable (in many member states the same organisation is not required to carry out both sampling and analysis under EN 14791). However, the data showed that, of those who had a preference for portable, sixteen (46%) had an in-house analytical capability whilst out of those who had a preference for EN 14791 only one (7%) used external analysis.


. The feedback below would suggest that AMSs are indeed in use on many medium combustion plants, with QAL2s being undertaken on these sites.


For medium combustion plants, as listed in Figure 4, portable instrumentation is most used when compliance testing, but less so for QAL2 testing. EN 14791 is used least at medium combustion plants, but it can also be seen that there are a high number of participants using both methods for compliance. EN 14791 is the most popular method for all types of medium combustion plant testing under QAL2, being used most commonly at single fuel waste incineration plants.


Trends in portable instrumentation varied across participants, the two most popular type of analyser were the Horiba NDIR (67% of respondents) and the Gasmet FTIR (44% of respondents). There were few notable trends by country, but every company from Italy who responded included the Horiba PG250/PG350 in their equipment list, with these models also proving popular in Finland. Germany, and the UK.


General Comments Returned


Respondents were asked for general comments on the application of both the SRM and portable techniques.


Asked what their preference would be in the absence of any regulator or national constraints it was found that 79% of Italian respondents and 66% of UK respondents preferred portable whilst 73% of German respondents preferred EN 14791. Interestingly, although all Swedish companies responded in favour of portable methods, the tests they reported offering are mainly in the use of both methods or EN 14791 alone (Figure 3).


It terms of commenting on the issues associated with each approach the most common responses were as follows. For EN 14791 44% reported issues in terms of handling glassware on-site listing contamination, quality of solutions, and space and logistics of setting up the sample train. 22% complained that data were not available in real-time and of sample train uncertainties in terms of frequency of user error in leak testing. Also, issues over freezing sample lines and solutions were listed, as might be expected from respondents residing in the cooler climates in the north of Europe.


Figure 4: Medium Plant SO2 Trends Observed


Of the organisations surveyed it is seen that 24% offered only testing to EN 14791, 21% offered only portable instrumentation techniques and the remaining 55% offered both. In Figure 3 the results are broken down by country: Belgium, Denmark, Estonia and France are excluded as there were too few respondents from these countries to draw any meaningful national comparisons. Of those remaining Finland had a high proportion of organisations offering only portable methods, Germany and Italy showed a high proportion of organisations offering only EN 14791, and Sweden and the UK showed a high proportion of organisations who offer both. None of the respondents from Germany or Sweden offered only portable. Of course, not every organisation in each nation is included in the survey, however, these trends are likely to be representative.


When considering large combustion plants in Figure 5 it is seen that portable instrumentation is used more often than EN 14791 in most cases. These numbers are significantly higher for coal and lignite, peat, and co-fired biomass combustion plants. Biomass and liquefied gas combustion plants have results which are much closer in number, but it must also be noted that many participants recorded using both methods for compliance testing.


The number using both methods is significantly lower for QAL2 testing, and in contrast to medium plants, portable instrumentation appears to be used more commonly than EN 14791. Two notably higher examples of portable instrumentation testing are on liquefied gas plants and co-fired biomass combustion plants. Alternatively, for biomass combustion the use of EN 14791 is significantly more popular.


Monitoring (Number of respondents)


With respect to portable methods, concerns due to bias caused by cross-interference from other species was mentioned by 44% of respondents, whilst 33% mentioned issues regarding losses in conditioning systems. Logistical issues of using gas cylinders on- site and permits to transport on the road were listed by 22% of respondents, whilst a small number complained about the time it takes to condition sampling systems on-site.


Conclusions


Respondents from 9 nations have highlighted a variety of issues from their experiences in using EN 14791 and portable instrumental techniques. With respect to the former, concerns expressed revolved mainly around contamination, quality of solutions and space / logistical requirements for setting up sampling trains on-site. With respect to the latter concerns were raised over cross-interference, losses in sampling systems and logistic issues with use / transport of gas cylinders. In terms of application we have seen that portable techniques are more commonly used for compliance measurements than QAL2, this perhaps being rationalised by differing regulatory approaches that in some member states would preclude the use of portable techniques, particularly for the latter.


www.envirotech-online.com IET November / December 2018


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  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108