Periodic Reporting for period 1 - GREEN RAY (New GeneRation marinE ENgines and Retrofit solutions to Achieve methane abatement flexibilitY)
Berichtszeitraum: 2022-06-01 bis 2023-11-30
Liquid natural gas (LNG) utilization in shipping is increasing and has direct effects, namely benefits on air quality and human health when comparing to oil-based marine fuels. Moreover, CO2 emission is lower with gas use compared to diesel fuels. The low-pressure dual fuel concept is the most popular LNG engine technology, which, however, is often associated with elevated levels of methane slip. Therefore, development of methane slip reduction technologies for these low-pressure dual fuel cases is the focus of this project.
There are two main objectives for the project. First, to assess the methane emissions from shipping. To achieve this, the GREEN RAY project will combine existing data collection with onboard measurements to address existing vessels and new builds, normal operation and varying loads, and further utilize these results in a model development to achieve LNG fleet level assessment. Moreover, these results are utilized in preventing the methane slip formation, which is the second main objective of the project.
To reduce methane slip, the GREEN RAY project will develop two on-engine technologies for low pressure dual fuel engines and an aftertreatment technology for the existing vessels as well as newbuilds. First, the four-stroke engine technology is developed further to enable methane slip reduction at all engine loads and to be applicable to the largest engines in the market involving cruise, ferry, and gas carriers. Second, the two-stroke engine development, around a patented LNG injection system, will aim to significantly reduce methane slip from e.g. tankers and container ships. Third, a unique approach of a sulphur resistant catalyst system is aiming to significant methane oxidation while also ensuring that the activity remains high over time. The achievements of these three technologies' development will be demonstrated onboard one new build and two retrofits to existing vessels, all of them targeting TRL 7.
Adapting the technologies developed in GREEN RAY makes it possible to achieve up to over 20% GHG benefit for LNG engines compared to oil-based engines. This is possible since the successful demonstration of technologies is expected to result in 40-90% methane slip reduction. Furthermore, all technologies are also developed to be capable of being utilized with bio- or synthetic gas instead of fossil LNG, maximizing the benefits for climate.
There are two main objectives for the project. First, to assess the methane emissions from shipping. To achieve this, the GREEN RAY project will combine existing data collection with onboard measurements to address existing vessels and new builds, normal operation and varying loads, and further utilize these results in a model development to achieve LNG fleet level assessment. Moreover, these results are utilized in preventing the methane slip formation, which is the second main objective of the project.
To reduce methane slip, the GREEN RAY project will develop two on-engine technologies for low pressure dual fuel engines and an aftertreatment technology for the existing vessels as well as newbuilds. First, the four-stroke engine technology is developed further to enable methane slip reduction at all engine loads and to be applicable to the largest engines in the market involving cruise, ferry, and gas carriers. Second, the two-stroke engine development, around a patented LNG injection system, will aim to significantly reduce methane slip from e.g. tankers and container ships. Third, a unique approach of a sulphur resistant catalyst system is aiming to significant methane oxidation while also ensuring that the activity remains high over time. The achievements of these three technologies' development will be demonstrated onboard one new build and two retrofits to existing vessels, all of them targeting TRL 7.
Adapting the technologies developed in GREEN RAY makes it possible to achieve up to over 20% GHG benefit for LNG engines compared to oil-based engines. This is possible since the successful demonstration of technologies is expected to result in 40-90% methane slip reduction. Furthermore, all technologies are also developed to be capable of being utilized with bio- or synthetic gas instead of fossil LNG, maximizing the benefits for climate.
During the first reporting period, we have extensively reviewed previous literature presenting emissions from LNG engines and vessels, and as a result, have provided an overview of the methane slip emission factors together with other emissions reported.
We have done two extensive experimental campaigns and studied emissions onboard two newbuild LNG-powered vessels. Measurement data from the first campaign are analyzed, while the data from the second campaign we are still processing.
The emission values collected from the literature and as measured onboard are being used as input values in updating the Ship Traffic Emission Assessment Model (STEAM) to consider especially the methane emissions from LNG vessels. The model revision work has started during the reporting period.
The 2S engine development is centered around the development of a first-of-a-kind system for injecting cryogenic (below 0°C) LNG fuel into 2S marine engines. The targeted technology will replace the existing gas admission valves and rail on operating DF engines with a new cryogenic gas valve and LNG rail. Therefore, a fuel supply and pumping system suitable to feed LNG to the engine was developed and installed in laboratory. To have a reference base of the performance, a first test was carried out with an LNG medium pressure injection system testing a stratified lean-charge pre-mixed “otto” combustion and a diffusive “diesel-like” combustion.
The success story of the recently released Wärtsilä 31DF engine performance upgrade will be continued also for the largest four-stroke engines by applying a similar novel combustion concept. In the first stage of the GREEN RAY project, different performance concepts have been simulated, analyzed, and also evaluated as a part of a whole vessel performance simulation of a field pilot candidate cruise ship. As a result of the collaborative effort in GREEN RAY, the direction for hardware implementation, testing and evaluation is defined. Next up is the rebuild of a full-size laboratory engine for testing and demonstration of the novel combustion technology.
During the first reporting period, significant improvements have also been made to the methane oxidation catalyst (MOC). Ageing experiments with the MOC have been conducted on a test unit where engine conditions are mimicked using a mixture of synthetic gases. Upstream of the MOC, a sulphur guard bed (SGB) catalyst is developed to achieve an overall sulphur resistant catalyst system. Optimization of the SGB has been done, following by experiments at accelerated conditions i.e. higher gas flows and higher SO2 concentrations than expected in practical applications. Further optimization of the MOC and SGB are still ongoing. The catalyst scale-up has also started and preparations for the engine lab tests are ongoing.
Planning of the technologies demonstration onboard has also started within the reporting period. One new generation four-stroke engine will equip a new build cruise vessel which will be delivered in 2026. The two-stroke engine technology development is planned to be installed on an existing engine in a container vessel during its dry dock planned in 2025. The methane oxidation catalyst system will be added at the outlet of a four-stroke engine in an existing LNG carrier in 2024.
We have done two extensive experimental campaigns and studied emissions onboard two newbuild LNG-powered vessels. Measurement data from the first campaign are analyzed, while the data from the second campaign we are still processing.
The emission values collected from the literature and as measured onboard are being used as input values in updating the Ship Traffic Emission Assessment Model (STEAM) to consider especially the methane emissions from LNG vessels. The model revision work has started during the reporting period.
The 2S engine development is centered around the development of a first-of-a-kind system for injecting cryogenic (below 0°C) LNG fuel into 2S marine engines. The targeted technology will replace the existing gas admission valves and rail on operating DF engines with a new cryogenic gas valve and LNG rail. Therefore, a fuel supply and pumping system suitable to feed LNG to the engine was developed and installed in laboratory. To have a reference base of the performance, a first test was carried out with an LNG medium pressure injection system testing a stratified lean-charge pre-mixed “otto” combustion and a diffusive “diesel-like” combustion.
The success story of the recently released Wärtsilä 31DF engine performance upgrade will be continued also for the largest four-stroke engines by applying a similar novel combustion concept. In the first stage of the GREEN RAY project, different performance concepts have been simulated, analyzed, and also evaluated as a part of a whole vessel performance simulation of a field pilot candidate cruise ship. As a result of the collaborative effort in GREEN RAY, the direction for hardware implementation, testing and evaluation is defined. Next up is the rebuild of a full-size laboratory engine for testing and demonstration of the novel combustion technology.
During the first reporting period, significant improvements have also been made to the methane oxidation catalyst (MOC). Ageing experiments with the MOC have been conducted on a test unit where engine conditions are mimicked using a mixture of synthetic gases. Upstream of the MOC, a sulphur guard bed (SGB) catalyst is developed to achieve an overall sulphur resistant catalyst system. Optimization of the SGB has been done, following by experiments at accelerated conditions i.e. higher gas flows and higher SO2 concentrations than expected in practical applications. Further optimization of the MOC and SGB are still ongoing. The catalyst scale-up has also started and preparations for the engine lab tests are ongoing.
Planning of the technologies demonstration onboard has also started within the reporting period. One new generation four-stroke engine will equip a new build cruise vessel which will be delivered in 2026. The two-stroke engine technology development is planned to be installed on an existing engine in a container vessel during its dry dock planned in 2025. The methane oxidation catalyst system will be added at the outlet of a four-stroke engine in an existing LNG carrier in 2024.
Altogether, based on the done review, the methane slip of LNG-powered vessels was found to vary roughly from 1 to 100 g/kWh, depending greatly e.g. on engine loading, engine type and model, with the highest values recorded at lowest engine loads.
Results from the first onboard experiments show that the methane emissions from a newbuild vessel are lower or equal to the lowest levels of the methane results collected from the previous studies. This already gives an indication that the engine technology development is on the right track in addressing the methane slip emissions while the GREEN RAY project is expected to significantly improve this addressing also e.g. the lower load conditions.
Results from the first test on 2S engine with cryogenic injection show a reduction of methane slip using cryogenic injection. The 4S development continues on the path proven with smaller engine bores, which together with simulation results give confidence also for large bore engines.
Results from the ageing experiments with the MOC showed good thermal stability for 16000 hours of operation while keeping the methane reduction at 75%. Moreover, the SGB studied in accelerated conditions, showed performance indicating operation time of approx. 16000 hours as well. These results allowed to start with the catalyst scale-up in preparation of the engine lab tests at the Wärtsilä facilities in Vaasa.
Results from the first onboard experiments show that the methane emissions from a newbuild vessel are lower or equal to the lowest levels of the methane results collected from the previous studies. This already gives an indication that the engine technology development is on the right track in addressing the methane slip emissions while the GREEN RAY project is expected to significantly improve this addressing also e.g. the lower load conditions.
Results from the first test on 2S engine with cryogenic injection show a reduction of methane slip using cryogenic injection. The 4S development continues on the path proven with smaller engine bores, which together with simulation results give confidence also for large bore engines.
Results from the ageing experiments with the MOC showed good thermal stability for 16000 hours of operation while keeping the methane reduction at 75%. Moreover, the SGB studied in accelerated conditions, showed performance indicating operation time of approx. 16000 hours as well. These results allowed to start with the catalyst scale-up in preparation of the engine lab tests at the Wärtsilä facilities in Vaasa.