Analytical Instrumentation Use of UVF Detectors with a Micro Plasma Optimiser (MPO)
When using UVF detectors, the already mentioned cross-sensitivity to NO can lead to distorted results. The fluorescence of NO tends to only have an intensity of 0.6 – 2% compared to the fluorescence intensity of SO2
, but in very nitrogen-rich samples with very low sulphur content this can
cause problems. For example: 200 ppm nitrogen lead to a total sulphur result of 1 – 4 ppm. With the very low limit values for fuels the limit value may thus quickly be exceeded as a false positive result.
However, especially in modern fuels, nitrogen compounds are added to improve the combustion properties. Substances, such as amyl nitrate, cyclohexyl nitrite or tri-ethylene glycol nitrite make up up to 5 %-wt, depending on the fuel. These so-called cetane improvers modify the ignitability and octane rating of petrol and diesel positively, but due to the increased nitrogen content ways must be found during the sulphur analysis using UVF detectors to eliminate this irrelevant content. This can be achieved by processing the analytes, e.g. by dilution with pure fuel. Or these expensive procedures are dispensed with and an interference-free detection method is used.
To measure samples with high nitrogen content, a UVF detector with the patented MPO technology was used. The MPO creates plasma in the gas flow that selectively oxidises NO to NO2
, so that
the combustion products of the nitrogen compounds no longer display a specific fluorescence. This allows for the real sulphur content to be detected even if there is a large mass percentage of nitrogen in the sample, without the need for additional processing steps.
Table 3 shows the sulphur content of different fuels dependent on the activity of an MPO. The detected mass percentage of nitrogen for the respective sample is also stated. This was measured using a chemiluminescence detector (CDL) located after the UVF detector in an additional detector module within the measuring gas flow. The software permits the easy change-over from single element mode with the MPO enabled for sulphur to multiple element mode with the MPO disabled. It becomes apparent that at higher nitrogen concentrations the use of the MPO is useful to derive the true sulphur content.
Table 3: Sulphur content with and without MPO enabled and corresponding nitrogen concentrations Sample
Diesel C Diesel D
Gasoline C Gasoline D
Summary The examples above demonstrate that the multi EA® 5000 is ideally suited as a versatile sulphur
analyser for the quick and simple monitoring of intermediate and end products. With its high measuring range and the flexibility of sample supply it permits the analysis of various matrices from highly viscous or solid to highly volatile material mixes. The use of an MPO further offers the option to perform reliable and specific analyses with the UVF detector used even where nitrogen content is high. The change-over from multiple element mode to single element mode is easily possible at any time, allowing the end user to adjust individually to the analytical problem faced.
The use of these methods is not only limited to fuels and their manufacture. There are many applications where a non-negligible amount of nitrogen is present in addition to sulphur in the analysis of organic matrices, such as polymers, grease, lubricants and oils for different uses as well as gases.
Sources [1]
http://www.ifqc.org/Spotlight.aspx?Id=135 accessed 2014-05-13 [2] a)
http://europa.eu/legislation_summaries/other/l21050_de.htm accessed 2014-05-13
[2] b)
http://www.imo.org/OurWork/Environment/PollutionPrevention/AirPollution/Pages/Sulphur- oxides-(SOx)
-%E2%80%93-Regulation-14.aspx accessed 2014-05-13
MPO on TS ± SD [ppm] MPO off TS ± SD TN ± SD 6.4 ± 0.07 9.8 ± 0.12 7.5 ± 0.07 11.9 ± 0.08
6.7 ± 0.14 10.5 ± 0.02 7.5 ± 0.03 11.9 ± 0.07
25.0 ± 0.01 73 ± 0.09 5.3 ± 0.07 3.0 ± 0.04
17
New Partnership Challenges Traditional Sensing with Innovative Technologies for HP Processes
Servomex (USA), provider of continuous gas analysis solutions for the Hydrocarbon Processing (HP) and Natural Gas (NG) industries, has joined forces with H2scan, provider of accurate, tolerant and affordable hydrogen leak detection and process gas monitoring solutions, to provide complete light hydrocarbon measurement and analytical solutions to its HP and NG customers.
The new partnership completes Servomex’s end-to-end offering for the innovative, multi component light hydrocarbon analyser and GC alternative the SERVOTOUGH SpectraScan by providing a more robust and reliable measurement of hydrogen in hydrocarbon gases, using a unique alternative technology to traditional thermal conductivity sensors. H2scan’s hydrogen-specific sensing system is uniquely able to detect hydrogen against virtually any background gases without false readings or expensive support equipment required.
Rhys Jenkins, Market Sector Manager at Servomex, explains: “Unlike thermal conductivity sensors, the H2scan does not require significant application development for each mix of hydrocarbon gases, yet it exceeds industry standards. The combination of the two new and innovative technologies in the H2scan and SpectraScan is a head on challenge to traditional GC industry options for hydrocarbon sensing. The result is superior, yet simpler detection for HP and NG applications at considerably lower implementation and product lifetime costs for our customers.”
The H2scan patented “Chip on a flex” technology provides a far more robust and reliable direct measurement of hydrogen than any thermal conductivity sensor, making it a natural collaborative partner for the SpectraScan “Tunable Filter Spectroscopy” optical sensor. As an out-of-the box solution, the H2scan is easily configurable alongside the SpectraScan and comes with customer support that matches Servomex’s own customer-centric ethos.
Michael Nofal, Vice President Sales & Business Development at H2scan said: “Our hydrogen specific sensing systems based on a patented “Chip on a flex” technology have the ability to operate in real-time. This is important for the SERVOTOUGH SpectraScan which also operates in real time, unlike GC technologies which have a time lag. We also bring a host of benefits in terms of the lowest total cost of ownership, low maintenance and longer calibration intervals, simple system integration and installation and tolerance to harsh background contaminants.”
For More Info, email: email:
For More Info, email: email:
30862pr@reply-direct.com
Mercury in Oil and Gas - Consult Those in the Know
Founded in 1983, P S Analytical (PSA) (UK) has been at the forefront of trace mercury (Hg) determination for over 30 years. Understanding the fate of Hg in all aspects of oil and gas exploration, refining and production is vitally important, and a great deal of effort is spent on Hg removal technology. Mercury is known to cause failure of aluminium heat exchangers and poisoning of hydrogenation catalysts. The replacement of equipment, plant downtime and health and safety issues are of real concern to plant operators. PSA partners with many companies to monitor and help manage this Hg removal process. These partnerships, beginning at research bench, continue through to production, with PSA taking a pivotal role in ensuring successful removal technologies are deployed in the real world.
The range of PSA analysers covers all aspects of the monitoring and analysis of Hg, including laboratory instruments, on-line analysers for gases and liquids and
solutions for speciation (fractionation) analysis and waste water systems associated with petrochemical processes.
Utilising Atomic Fluorescence as a means of detection PSA analysers provide excellent detection performance. With literally thousands of systems in the field today, and support networks in Europe, USA and SE Asia, PSA offers the ideal package of performance, reliability and support.
For More Info, email: email:
For More Info, email:
30943pr@reply-direct.com
For More Info, email: email:
AUGUST / SEPTEMBER •
WWW.PETRO-ONLINE.COM
For More Info, email: email:
3255ad@reply-direct.com
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
