| 1. |
- Alföldy, B., et al.
(författare)
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Measurements of air pollution emission factors for marine transportation in SECA
- 2013
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 6:7, s. 1777-1791
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Tidskriftsartikel (refereegranskat)abstract
- The chemical composition of the plumes of seagoing ships was measured during a two week long measurement campaign in the port of Rotterdam, Hoek van Holland The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg(-1) fuel) was provided. The concerned main atmospheric components were SO2, NO2, NOx and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was determined. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 vs. 30 g kg(-1) fuel), and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factors. The intercept of the regression line, 4.8 x 10(15) (kg fuel)(-1), gives the average number of particles formed during the burning of 1 kg zero sulphur content fuel, while the slope, 2 x 10(18), provides the average number of particles formed with 1 kg sulphur burnt with the fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that similar to 144 g of particulate sulphate was emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was similar to 42 nm.
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| 2. |
- Berg, Niklas, 1980
(författare)
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Remote Measurements of Ship Emissions
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The combustion of sulphur-containing fossil fuels gives rise to emissions of sulphurdioxide. Nitrogen oxides are also emitted when fuels are burned. The InternationalMaritime Organization (IMO) has ratified regulations regarding Sulphur Fuel Content(SFC) and NOx emissions from the shipping sector. There is economic incentive to ignorelegislation and run with cheaper residual fuel that contains high concentrations of sulphur.In open waters, there is no effective method of controlling whether ships are running onlow or high sulphur fuel.A surveillance system, denoted Identification of Gross Polluting Ships (IGPS), has beendeveloped and used with the objective of enforcing the use of low sulphur fuel and NOxabatement equipment according to the new conventions within the IMO.The system is foremost an airborne system consisting of an optical remote measuringsystem for total emission measurements of SO2 or NO2 from ships. When the emissionvalues reach a certain threshold, an aircraft flies into the ship’s exhaust and takes in situmeasurements, denoted the sniffer system, from which SFC and NOx g/kg fuelmeasurements are obtained.The uncertainty for the optical measurements is estimated to be approximately 45% withoptical and wind as the largest uncertainty sources. Estimates of the overall uncertaintyfor the sniffer measurements, derived during a campaign in Rotterdam, corresponds to14% for SO2 (S%) and 33% for NO (g/kg fuel). For the emission factors of NOx versusaxial power, g/kWh, the uncertainty is 37%. It should be noted that the NO uncertaintywas unusually high due to instrument problems.Measurement campaigns have been carried out in the Baltic and North Seas using aCASA-212 aeroplane and a Dauphin helicopter. Optical measurements show thepossibility to detect SO2 and NO2 emission from ships. Many of the ocean going shipshad a total emission of 60 kg/h SO2. The sniffer measurements showed good agreementwith the current IMO regulations for the majority of ships. When the strictest IMOregulation of 0.1% SFC is introduced, ships using fuels with 0.5-4.5% SFC will be easilydetected with the current uncertainties.
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| 3. |
- Berg, Niklas, 1980, et al.
(författare)
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Ship emissions of SO2 and NO2: DOAS measurements from airborne platforms
- 2012
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 5:5, s. 1085-1098
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Tidskriftsartikel (refereegranskat)abstract
- A unique methodology to measure gas fluxes of SO2 and NO2 from ships using optical remote sensing is described and demonstrated in a feasibility study. The measurement system is based on Differential Optical Absorption Spectroscopy using reflected skylight from the water surface as light source. A grating spectrometer records spectra around 311 nm and 440 nm, respectively, with the telescope pointed downward at a 30A degrees angle from the horizon. The mass column values of SO2 and NO2 are retrieved from each spectrum and integrated across the plume. A simple geometric approximation is used to calculate the optical path. To obtain the total emission in kg h(-1) the resulting total mass across the plume is multiplied with the apparent wind, i.e. a dilution factor corresponding to the vector between the wind and the ship speed. The system was tested in two feasibility studies in the Baltic Sea and Kattegat, from a CASA-212 airplane in 2008 and in the North Sea outside Rotterdam from a Dauphin helicopter in an EU campaign in 2009. In the Baltic Sea the average SO2 emission out of 22 ships was (54 +/- 13) kg h(-1), and the average NO2 emission was (33 +/- 8) kg h(-1), out of 13 ships. In the North Sea the average SO2 emission out of 21 ships was (42 +/- 11) kg h(-1), NO2 was not measured here. The detection limit of the system made it possible to detect SO2 in the ship plumes in 60% of the measurements when the described method was used. A comparison exercise was carried out by conducting airborne optical measurements on a passenger ferry in parallel with onboard measurements. The comparison shows agreement of (-30 +/- 14)% and (-41 +/- 11)%, respectively, for two days, with equal measurement precision of about 20%. This gives an idea of the measurement uncertainty caused by errors in the simple geometric approximation for the optical light path neglecting scattering of the light in ocean waves and direct and multiple scattering in the exhaust plume under various conditions. A tentative error budget indicates uncertainties within 30-45% but for a reliable error analysis the optical light path needs to be modelled. A ship emission model, FMI-STEAM, has been compared to the optical measurements showing an 18% overestimation and a correlation coefficient (R-2) of 0.6. It is shown that a combination of the optical method with modelled power consumption can estimate the sulphur fuel content within 40%, which would be sufficient to detect the difference between ships running at 1% and at 0.1%, limits applicable within the IMO regulated areas.
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| 4. |
- Loov, J. M. B., et al.
(författare)
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Field test of available methods to measure remotely SOx and NOx emissions from ships
- 2014
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:8, s. 2597-2613
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Tidskriftsartikel (refereegranskat)abstract
- Methods for the determination of ship fuel sulphur content and NOx emission factors based on remote measurements have been compared in the harbour of Rotterdam and compared to direct stack emission measurements on the ferry Stena Hollandica. The methods were selected based on a review of the available literature on ship emission measurements. They were either optical (LIDAR, Differential Optical Absorption Spectroscopy (DOAS), UV camera), combined with model-based estimates of fuel consumption, or based on the so called "sniffer" principle, where SO2 or NOx emission factors are determined from simultaneous measurement of the increase of CO2 and SO2 or NOx concentrations in the plume of the ship compared to the background. The measurements were performed from stations at land, from a boat and from a helicopter. Mobile measurement platforms were found to have important advantages compared to the land-based ones because they allow optimizing the sampling conditions and sampling from ships on the open sea. Although optical methods can provide reliable results it was found that at the state of the art level, the "sniffer" approach is the most convenient technique for determining both SO2 and NOx emission factors remotely. The average random error on the determination of SO2 emission factors comparing two identical instrumental set-ups was 6 %. However, it was found that apparently minor differences in the instrumental characteristics, such as response time, could cause significant differences between the emission factors determined. Direct stack measurements showed that about 14% of the fuel sulphur content was not emitted as SO2. This was supported by the remote measurements and is in agreement with the results of other field studies. S, 1984, Notes on Heavy Fuel Oil
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| 5. |
- Mellqvist, Johan, 1965, et al.
(författare)
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IDENTIFICATION OF GROSS POLLUTING SHIPS
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The aim in this project is to develop and test techniques for the surveillance of gas emissions of SO2 and NOx from ships, to enforce new low sulfur regulation within the International Maritime Organization (IMO). The regulation puts a cap on the sulfur fuel content of 1.5% for ships traveling on the Baltic Sea, North Sea and the English Channel. It is driven by the fact that the emissions of sulfur and NOx in Europe are projected to exceed the land based emissions by 2020. Low sulfur fuel is expensive and since surveillance methods for ship emissions are missing it is questionable whether the new legislation will be respected. This project has been funded by Vinnova, the provincial government of Västra Götaland and the Swedish Maritime Organization.Two types of instrument systems have been employed: The optical system which measures SO2 and NO2 in the flue gases of the ships remotely, by spectral analysis of direct or reflected solar light. From this it is possible to derive the emission rate in mass per time unit. The other system, denoted the sniffer system, is based on the extraction of flue gases through a sonde into the instruments located either in the airplane or in the stationary measurement location. The concentration ratio of SO2 to CO2 is measured and this value is directly proportional to the sulfur fuel content in the ship plume. The system also measures the NOx to CO2 ratio from which the emission in mass per fuel unit is obtained and emission per kWh as given in legislation. The sniffer measurement requires direct contact with the ship plume. The optical system is unique although a similar technique is applied for global satellite monitoring. Similar systems to the sniffer one have been employed by other research groups for airborne measurements of ship emissions. However, their work has been limited to measurements of a few ships, as part of air pollution campaigns, with no focus on surveillance and legal enforcement. The sniffer system, when operated in this project, had an estimated measurement uncertainty of 15% for the sulfur content, with a negative bias of 4%, and a 21% uncertainty for the measurements of NOx emission versus axial power (g NOx/kWh). For the optical system the uncertainty is difficult to assess but roughly it corresponds to 30-50%. If one considers the overall uncertainty for SO2, then the sniffer measurement has to measure above 1.8% sulfur fuel content, to detect a non complying ship regarding the IMO limit. For the NOx emissions it is uncertain whether the measurement accuracy of the IGPS system is sufficient to check compliance with the coming regulation requiring 20% reduction (Tier II), but whenever it is decided to introduce environmental control areas for NOx with 80% required NOx reduction (Tier III) then this will be rather easy to control.In May and June 2007, stationary measurements with the Sniffer and optical system were carried out at Nya Älvsborgs fästning, an old fortress, on the north side of the ship channel into Göteborg. From these measurements, 220 ship plumes corresponding to 80 individual ships, were identified and analyzed. A large fraction of the ship plumes (50 out of 220) corresponded to plumes from ferry boats, predominately from Stena line. The measured data was compared to certain ships for which the sulfur fuel content was known. All in all, a good agreement was obtained when comparing the results to ships with known sulfur fuel values of 0.1%, 0.5% and 1.1%, respectively. This has to be further studied. Three ships out of the eighty were above the IMO limit of 1.5% in the harbor study.In August 2007 and 2008, respectively, the IGPS (Identification of Gross Polluting Ships) measurement system was installed in the CASA-212 airplane KBV-583 of the Swedish coastguard and 20 test flights with a duration of 2 hours were conducted in the Baltic sea, east of the Island of Gotland, and between Denmark and Sweden. A total of 343 measurements were done with the sniffer instrument corresponding to 95 individual ships. The measurements were shared about equal between SO2 and NOx, being able to measure only these species one at a time in the experimental setup. On average the ships had a sulfur content of 1.28% and only 3 ships were with certainty above the IMO SECA limit of 1.5%, when considering the measurement uncertainty. The ships, on average, emitted 13 gNOx/kWh (66 g NOx/kg fuel) and the ships seemed in general to comply with the Tier I IMO standard, considering the uncertainties. A thorough investigation of emission versus crankshaft speed has not been done, however. The optical instrument was able to obtain fluxes in 66% of the ship measurements; 70 flux measurements [kg/h] of SO2 or NO2 were conducted on 35 individual ships. On average the SO2 and NO2 emission were 54 kg/h and 33 kg/h, respectively.
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