Fuel quality measurements at small-scale LBG refuelling stations Anders Karlsson, SP LNG Workshop , NPL, London, UK

Transcription

1 Fuel quality measurements at small-scale LBG refuelling stations Anders Karlsson, SP LNG Workshop , NPL, London, UK

2 LNG / LBG in Sweden

3 LNG / LBG in Sweden

4 LNG / LBG in Sweden Since 2010 the station located in Gothenburg, Sweden delivers liquefied biomethane to heavy and medium duty trucks. But in rare occasions, the tank may be filled with LNG. The LNG/LBG is delivered from a biogas plant by a trailer BOG CNG LNG

5 Gas quality variation The truck engines are based on different technologies Depending on the technology the engine is more or less sensitive to different fuel qualities or specific parameters The engine technologies have different critical design criteria and can be optimized for a larger or smaller window. Typically, dual fuel technology is more sensitive to varying gas qualities compared to spark ignited engines in terms of knocking. However, spark ignited engines are optimized based on specific gas properties.

6 LNG Blue Corridor Jönköping is one of the stations of the LNG blue corridor

7 LNG Blue corridor, gas quality discussion Aspects to be considered, related to gas quality, which affect the engine and gas infrastructure: Hydrogen: Risk of embrittlement for the metallic materials Water: Risk of corrosion and driveability problems. Hydrogen sulfide: Corrosive in the presence of water, could affect after-treatment devices, combustion products could cause problems by sticking to the engine valves.

8 LNG Blue corridor, gas quality discussion Key parameters discussed regarding LNG and EURO 6 engines are: Methane Number: The higher MN the better possibility to optimize engine Wobbe Index: Narrow interval helps to fulfil EURO 6 in terms of specified power and torque. Temperature/Pressure: Technology road path indicates need of two pressure intervals: Spark ignited: minimum ~10 bars HPDI and similar technologies: As cold as possible Siloxanes: Limit needed to secure engine durability (risk of abrasion and increased probability for knocking)

9 Task 2.4. Ageing effects at LNG/LBG storage and filling stations Boiling temperature ( C) Nitrogen Methane Ethane Propane n-butane i-butane Neo-Pentane 9.50 i-pentane n-pentane Carbon dioxide proceedings/storage-4-angel_benito.pdf

10 Task 2.5. Particulate measurements of LNG Stakeholder comments Westport Innovations Inc. (Westport), engineering the world's most advanced natural gas engines and vehicles, is making progress with its Westport High Pressure Direct Injection (Westport HPDI) second generation or "HPDI 2.0" development program. The Westport HPDI technology is particularly adapted for heavy duty LNG trucks. In October 2015, Westport announced it has entered into new agreements with Volvo Group governing the development, commercial launch and supply of Westport HPDI 2.0 technology in its heavy-duty trucks over the next several years. One specific feature of the HPDI system is its high pressure LNG pump located in the LNG tank, which does have a low tolerance to particles. To achieve customer expectations for product cost and LNG pump maintenance intervals at launch, the LNG needs to be delivered clean. Solid particles would otherwise grind the seals and the coating of the pump, leading gradually to material loss from the seals, resulting in turn in LNG pump performance falling below the required fuel delivery rate. Contaminations have been observed by measuring the rate of seal wear at stations equipped with an appropriate fuel filter compared to stations without a fuel filter, showing that the rate of seal wear significantly increases at the latter ones. Measuring the currently available LNG quality with regards to particles is necessary to evaluate the LNG fuel cleanliness and must be done following the same process at all tested sites in order to provide comparable results. These results are needed to develop future onboard filtration solutions and to define filter maintenance intervals. The LNG sampling equipment and particles measurement process will also be a useful diagnostic tool to resolve operational issues.

11 LNG / LBG in Sweden: Sampling conditions Task 2.2. Improved Sampling Techniques Space a limiting factor

12 LNG / LBG in Sweden: Sampling conditions Task 2.2. Improved Sampling Techniques Space a limiting factor Insulation required to avoid prevaporization

13 LNG / LBG in Sweden: Sampling conditions Task 2.2. Improved Sampling Techniques Space a limiting factor Insulation required to avoid prevaporization Sampler: Mobile Time for sampling limited -> needs to be quickly stabilized (temperatures/flow) A heated and insulated coil of 6m ¼ -SS tubing -> high linear velocity 5 measurement ports (temperature)

14 LNG / LBG in Sweden: Sampling conditions Effects of heating and flow rate Unit With warming Without warming With warming T1 C -140 ± ± 5-100± 5 T2 C -80 ± 5 T3 C -20 ± 5 T4 C 0 ± 5 T5 C 35 ± ± 5 40 ± 5 Gas flow l/min stable at 60 ± 5 l/min* Unstable (up to 115 but often about 60 ± 5 30 ± 5 l/min* P bar Liquid LBG visible at the end of the sampler

15 LNG / LBG in Sweden: Sampling conditions Effects of heating and flow rate Theoretical values Measurements Vol-% 60 l/min 30 l/min Methane ± Ethane ± ± 0.01 propane ± ± 0.01 Isobutane <0.001 Butane <0.001 <0.001 <0.001 Oxygen ± ± 0.05 Nitrogen Carbon dioxide <0.1 <0.1 Isopentane <0.001

16 Thank you for your attention!