The HyMethShip project (Hydrogen-Methanol Ship Propulsion Using On-board Pre-combustion Carbon Capture) is a cooperative R&D project funded by the European Union’s Horizon 2020 research and innovation programme. The project aims to drastically reduce emissions while improving the efficiency of waterborne transport. The HyMethShip system will achieve a reduction in CO2 of more than 97% and practically eliminate SOx and PM emissions. NOx emissions will fall by over 80%. below the IMO Tier III limit. The energy efficiency of the HyMethShip system is expected to be more than 45% greater than the best available technology (renewable methanol as the fuel coupled with conventional post-combustion carbon capturing). The HyMethShip system innovatively combines a membrane reactor, a CO2 capture system, a storage system for CO2 and methanol as well as a hydrogen-fueled combustion engine into one system. Methanol is reformed to hydrogen, which is then burned in a conventional reciprocating engine that has been upgraded to burn multiple fuel types and specially optimized for hydrogen use. The basic engine type is the same as the one currently used on the majority of ships. This project will develop this system further and integrate it into shipboard installations. The system will be developed, validated, and demonstrated on-shore on an engine in the range of 1 to 2 MW. The project started in 2018 and will run for 3 years. The work is structured into 11 work packages that deal with the pre-combustion carbon capture system and the internal combustion engine as well as assess safety, economic and environmental factors and system integration. The consortium consists of 13 partners including a globally operating shipping company, a major shipyard, a ship classification society, research institutes and universities and equipment manufacturers. The publication will present the structure of the work and preliminary results of the project.
The majority of modern large bore gas engines are operated using a lean combustion concept to comply with existing NOx emission limits without exhaust aftertreatment. Prospective emission regulations call for significantly lower NOx emissions. Engine internal measures to achieve this goal include further enleanment of the cylinder charge and high EGR ratios. Exhaust gas aftertreatment increases the size of the engine system; greater power output compensates for the demand for more space. High specific engine power, very lean mixtures or high EGR ratios pose high demands to the ignition of the mixture. This paper compares the potentials of three different ignition concepts (spark ignition, laser ignition and diesel pilot ignition) applied to large engines. First, the basics of the ignition concepts are compared by theoretical considerations with respect to available ignition energy and temperature, introduced turbulence and stochastic influences. Measurements from the single cylinder research engine are used to evaluate the influence of the ignition source based on the achievable efficiency and emissions values. Furthermore, the impact on cycle-to-cycle variations is assessed. When the ignition systems are compared, the boundary conditions of the cases under investigation are set to identical values whenever possible. Finally, the measurement results are further analyzed based on 3D CFD simulation. Highly sophisticated simulation models already validated in prior research are applied in order to simulate the processes relevant to ignition, flame kernel development and combustion. For the modeling of spark ignition, a spherical ignition model is used providing a defined initial flame kernel at the spark plug over the duration of energy deposit by the ignition system. Laser ignition is considered by an ignition model that generates an infant flame kernel represented by a sphere inside the combustion chamber. The size of the sphere is provided by a detailed plasma model for the blast wave resulting from the instantaneous energy release by the focused laser beam. Finally, for diesel pilot ignition a detailed reaction mechanism is used to obtain the relevant ignition delay values. The models are used in connection with 3D CFD simulation, which also provides the required turbulence values. The effect of each ignition concept on the induced energy to the cylinder charge as well as on the evolution of the initial flame front is investigated. Powered by TCPDF (www.tcpdf.org) CIMAC Congress 2019, Vancouver Paper No. 314 Page 3
