The Experts below are selected from a list of 6123 Experts worldwide ranked by ideXlab platform

Thomas Joseph Condra - One of the best experts on this subject based on the ideXlab platform.

  • modeling and optimization of integrated exhaust gas recirculation and multi stage waste heat recovery in Marine Engines
    Energy Conversion and Management, 2017
    Co-Authors: Fotis Kyriakidis, Kim Sorensen, Shobhana Singh, Thomas Joseph Condra
    Abstract:

    Abstract Waste heat recovery combined with exhaust gas recirculation is a promising technology that can address both the issue of NO x (nitrogen oxides) reduction and fuel savings by including a pressurized boiler. In the present study, a theoretical optimization of the performance of two different configurations of steam Rankine cycles, with integrated exhaust gas recirculation for a Marine diesel engine, is presented. The first configuration employs two pressure levels and the second is configured with three-pressure levels. The models are developed in MATLAB based on the typical data of a large two-stroke Marine diesel engine. A turbocharger model together with a blower, a pre-scrubber and a cooler for the exhaust gas recirculation line, are included. The steam turbine, depending on the configuration, is modeled as either a dual or triple pressure level turbine. The condensation and pre-heating process is optimized to utilize the maximum waste heat recovery. The Genetic algorithm and fmincon active-set algorithm are used to optimize the design and operation parameters for the two steam cycles. The optimization aims to find the theoretically optimal combination of the pressure levels and pinch-point temperatures to maximize the power production. Results show that the two-pressure level steam cycle produces 1577 kW of net power; whereas the three-pressure level cycle produces 1641 kW at full load operation. The optimum pressure levels for the two-pressure level configuration are found to be 33.4/4.7 bar a . For the three-pressure level configuration, the optimum pressure levels are found to be 33.5/10.5/4.7 bar a . The amount of waste heat recovery from the pressurized boiler is significantly higher than from the main boiler for both cycles. It is, therefore, concluded that the three-pressure level steam cycle (configuration 2) is more efficient than the two pressure level cycle (configuration 1). At the same time, the engine equipped with waste heat recovery with a three-pressure level steam cycle is simpler to operate in Tier II operation. However, the two-pressure level steam cycle is a simpler configuration.

Hilkka Timonen - One of the best experts on this subject based on the ideXlab platform.

  • particulate mass and nonvolatile particle number emissions from Marine Engines using low sulfur fuels natural gas or scrubbers
    Environmental Science & Technology, 2019
    Co-Authors: Kati Lehtoranta, Paivi Aakkosaksa, Timo Murtonen, Hannu Vesala, Leonidas Ntziachristos, Topi Ronkko, Panu Karjalainen, Niina Kuittinen, Hilkka Timonen
    Abstract:

    In order to meet stringent fuel sulfur limits, ships are increasingly utilizing new fuels or, alternatively, scrubbers to reduce sulfur emissions from the combustion of sulfur-rich heavy fuel oil. The effects of these methods on particle emissions are important, because particle emissions from shipping traffic are known to have both climatic and health effects. In this study, the effects of lower sulfur level liquid fuels, natural gas (NG), and exhaust scrubbers on particulate mass (PM) and nonvolatile particle number (PN greater than 23 nm) emissions were studied by measurements in laboratory tests and in use. The fuel change to lower sulfur level fuels or to NG and the use of scrubbers significantly decreased the PM emissions. However, this was not directly linked with nonvolatile PN emission reduction, which should be taken into consideration when discussing the health effects of emitted particles. The lowest PM and PN emissions were measured when utilizing NG as fuel, indicating that the use of NG cou...

  • Particulate Mass and Nonvolatile Particle Number Emissions from Marine Engines Using Low-Sulfur Fuels, Natural Gas, or Scrubbers
    2019
    Co-Authors: Kati Lehtoranta, Timo Murtonen, Hannu Vesala, Leonidas Ntziachristos, Panu Karjalainen, Niina Kuittinen, Päivi Aakko-saksa, Topi Rönkkö, Hilkka Timonen
    Abstract:

    In order to meet stringent fuel sulfur limits, ships are increasingly utilizing new fuels or, alternatively, scrubbers to reduce sulfur emissions from the combustion of sulfur-rich heavy fuel oil. The effects of these methods on particle emissions are important, because particle emissions from shipping traffic are known to have both climatic and health effects. In this study, the effects of lower sulfur level liquid fuels, natural gas (NG), and exhaust scrubbers on particulate mass (PM) and nonvolatile particle number (PN greater than 23 nm) emissions were studied by measurements in laboratory tests and in use. The fuel change to lower sulfur level fuels or to NG and the use of scrubbers significantly decreased the PM emissions. However, this was not directly linked with nonvolatile PN emission reduction, which should be taken into consideration when discussing the health effects of emitted particles. The lowest PM and PN emissions were measured when utilizing NG as fuel, indicating that the use of NG could be one way to comply with up-coming regulations for inland waterway vessels. Low PN levels were associated with low elemental carbon. However, a simultaneously observed methane slip should be taken into consideration when evaluating the climatic impacts of NG-fueled Engines

Jerzy Kowalski - One of the best experts on this subject based on the ideXlab platform.

  • fault diagnosis of Marine 4 stroke diesel Engines using a one vs one extreme learning ensemble
    Engineering Applications of Artificial Intelligence, 2017
    Co-Authors: Jerzy Kowalski, Bartosz Krawczyk, Michal Woźniak
    Abstract:

    This paper proposes a novel approach for intelligent fault diagnosis for stroke Diesel Marine Engines, which are commonly used in on-road and Marine transportation. The safety and reliability of a ship's work rely strongly on the performance of such an engine; therefore, early detection of any type of failure that affects the engine is of crucial importance. Automatic diagnostic systems are of special importance because they can operate continuously in real time, thereby providing efficient monitoring of the engine's performance. We introduce a fully automatic machine learning-based system for engine fault detection. For this purpose, we monitor various signals that are emitted by the engine, and we use them as an input for a pattern classification algorithm. This action is realized by an ensemble of Extreme Learning Machines that work in a decomposition mode. Because we address 14 different faults and a correct operation mode, we must handle a 15-class problem. We tackle this task by binarization in one-vs-one mode, where each Extreme Learning Machine is trained on a pair of classes. Next, Error-Correcting Output Codes are used to reconstruct the original multi-class task. The results from experiments that were conducted on a real-life dataset demonstrate that the proposed approach delivers superior classification accuracy and a low response time in comparison with a number of state-of-the-art methods and thus is a suitable choice for a real-life implementation on board a ship.

  • concept of the multidimensional diagnostic tool based on exhaust gas composition for Marine Engines
    Applied Energy, 2015
    Co-Authors: Jerzy Kowalski
    Abstract:

    Abstract This paper presents the concept of a multi-dimensional Marine engine diagnostic tool. The dimensions of the tool are diagnostic signals, which form a vector in affine space. The distance of the resulting vector from reference vectors for considered technical states of the engine is the result of diagnosis. Moreover, diagnostic signals, derived from the composition of the exhaust gas, are also considered. The chosen diagnostic signals are the nitric oxide, carbon oxide, carbon dioxide and oxygen contents in the exhaust gas and the temperatures behind all engine cylinders of the Marine engine. Analyses were based on laboratory tests of a 4-stroke Marine engine. The operation of the proposed diagnostic tool has been partly verified by a passive experiment under sea operation conditions of a main propulsion Marine engine.

Katarzyna Gawdzińska - One of the best experts on this subject based on the ideXlab platform.

  • An overview of systems supplying water into the combustion chamber of diesel Engines to decrease the amount of nitrogen oxides in exhaust gas
    Journal of Marine Science and Technology, 2015
    Co-Authors: Leszek Chybowski, Rafał Laskowski, Katarzyna Gawdzińska
    Abstract:

    The paper analyses legal requirements for the composition of exhaust gas emitted by ships, Marine Engines including. The background for this paper is the increasingly stricter limits set for the emission of the toxic exhaust gas components by Marine Engines. Legal requirements force designers to search for new constructions of Marine propulsion systems and constantly improve the existing ones. One of the solutions is supplying water into the combustion chambers of diesel Engines—the solution widely known for many years n ow wins favour and, according to the authors, has a chance to gain competitive advantage over alternative constructions. A special attention has been paid to the allowed amount of nitrogen oxides and sulphur oxides in exhaust gas resulting from the International Convention for the Prevention of Pollution from Ships. So far, one, global evaluation of brand new and retrofitted Marine propulsion system designs presenting this issue thoroughly has not been done. The authors’ interest in the issue derives from this fact and has been confirmed by many papers. We showed the mechanism of decreasing nitrogen oxides in exhaust gas by means of water supply into the combustion chambers of diesel Engines. We presented an overview of designs which might be used to retrofit vessels already in operation or introduced at the stage of vessel construction in the shipyard. The paper also contains an evaluation of the described designs. The following systems have been discussed: continuous water injection into the scavenging air, humid air motor, direct water injection with the use of combined nozzles, water-cooled residual gas system and fuel–water emulsion supply system using emulsifiers or devices of high-pressure water injection into fuel. We have made a comparison of the effectiveness of different methods used to reduce the emission of nitrogen oxides. Advantages and disadvantages of supplying water into the combustion chambers of diesel Engines have been shown together with the comparison of the range of changes in their construction. The authors have indicated potential opportunities derived from injecting Brown’s gas into the combustion chamber in order to change the composition of the exhaust gas. As a consequence, it will also affect the natural environment where vessels operate.

Theotokatos Gerasimos - One of the best experts on this subject based on the ideXlab platform.

  • A comparative life cycle assessment study on environmental performances between battery powered and conventional Marine vessels
    'Informa UK Limited', 2021
    Co-Authors: Wang Haibin, Boulougouris Evangelos, Theotokatos Gerasimos, Priftis Alexandros, Shi Guangyu, Zhou Peilin
    Abstract:

    International Maritime Organization (IMO) has initialized a new strategy on greenhouse gas (GHG) to reduce 50% of GHG from international shipping by 2050 comparing to 2008. Recently, solutions, like fuel cell and renewable energy, have been proposed by technology providers and ship designers. Bat-tery-powered ship is a solution that can lead to a considerable reduction or even elimination of gaseous emissions, thus limiting fossil fuels consumptions. This paper aims to determine the benefits and drawbacks of Marine battery propulsion system by conducting a comparative study using Life Cycle Assessment (LCA). It holistically evaluates the performances of the proposed system and the respective conventional one, ap-plied on a 33-meter-long short-route ferry operating on the Thames. The results indicate the battery-powered system instead of Marine Engines can reduce the environmental impacts and GHG from ships, which fulfils the IMO requirements and proves the emission control potential of battery-powered systems

  • Safety performance assessment of a Marine dual fuel engine by integrating failure mode, effects and criticality analysis with simulation tools
    'SAGE Publications', 2021
    Co-Authors: Stoumpos Sokratis, Theotokatos Gerasimos, Bolbot Victor, Boulougouris Evangelos
    Abstract:

    Marine Dual Fuel Engines have been proved an attractive solution to improve the shipping industry sustainability and environmental footprint. Compared to the conventional diesel Engines, the use of additional components to accommodate the natural gas feeding is associated with several safety implications. To ensure the engine safe operation, appropriate engine control and safety systems are of vital importance, whilst potential safety implications due to sensors and actuators faults or failures must be considered. This study aims at investigating the safety issues of a dual fuel (DF) engine considering critical operating scenarios, which are identified by employing a Failure Mode, Effects and Criticality Analysis. An existing verified digital twin (DT) of the investigated DF engine, capable of predicting the engine response at steady state and transient conditions with sufficient accuracy is employed to simulate the engine operation for the identified scenarios. The simulated scenarios results analysis is used to support the risk priority number assessment and identify the potential safety implications by considering the manufacturer alarm limits. Appropriate measures are recommended for DF Engines safety performance improvement. This study demonstrates a methodology integrating existing safety methods with state-of-the-art simulation tools for facilitating and enhancing the safety assessment process of Marine Engines considering both steady state conditions and transient operation with main focus on switching operating modes

  • A novel method for in-cylinder pressure prediction using the engine instantaneous crankshaft torque
    'SAGE Publications', 2021
    Co-Authors: Tsitsilonis Konstantinos-marios, Theotokatos Gerasimos
    Abstract:

    Current practices of condition assessment in large Marine Engines are largely based on the measurement of cylinder pressure using external kits, which poses challenges due to sensors synchronisation and durability issues, as well as the inability to perform continuous monitoring. For addressing these challenges, this study aims at developing a novel method to solve the inverse problem of predicting the pressure variations in all engine cylinders, by using the Instantaneous Crankshaft Torque (ICT) measurement for large internal combustion Engines. This method is developed by considering the Initial Value Problem (IVP) technique along with the integration of a direct crankshaft dynamics model incorporating the sensitivity parameters and stability criteria calculation based on the Lyapunov Exponent (LE) as well as a state-of-the-art Nonmonotone Self-Adaptive Levenberg-Marquardt (NSALMN) optimisation algorithm. The method is tested for a number of case studies using different combustion models based on the Weibe and sigmoid functions, as well as for healthy, degraded and faulty engine conditions. The derived results demonstrate adequate accuracy exhibiting a maximum error of 0.3% in the prediction of the mean peak in-cylinder pressure. The analysis of the calculated sensitivity parameters resulted in the identification of the parameters that significantly impact the solution, thus providing improved insights for selecting the developed method settings. The developed method renders the continuous and non-intrusive in-cylinder pressures monitoring feasible, by using a permanently installed shaft power metre sensor with higher sample rates

  • A novel objective oriented methodology for Marine engine-turbocharger matching
    'SAGE Publications', 2021
    Co-Authors: Mizythras Panagiotis, Boulougouris Evangelos, Theotokatos Gerasimos
    Abstract:

    The matching of the turbocharging system with a Marine engine is an essential undertaking due to the turbocharger effects on the engine performance, emissions and response, whilst the limited data availability during the ship design phase renders it challenging. This study aims at developing a novel methodology for the matching of a single turbocharger and multiple turbochargers connected in parallel with Marine Engines. This methodology employs a compressor parametric modelling tool and a zero-dimensional engine model, whilst taking into account the engine operational profile and the turbocharger components flow limitations. The compressor parametric tool is used for the generation of a database with compressor families that can be investigated during the matching procedure. The model of one engine cylinder block is used for mapping the engine performance parameters at a wide engine operating envelope by developing response surfaces. The developed methodology is implemented for the case study of the turbocharger matching with the propulsion engine of an Aframax tanker. The annual fuel consumption and the engine load diagram upper limit are employed as the main objectives for the selection the turbocharging system. The derived results demonstrate that the effective turbocharger matching results in reducing the engine brake specific fuel consumption up to 5%. The identified turbochargers led to the reduction of the ship annual fuel consumption in the range 1.3%–5.3% compared to the reference engine, whilst providing a more expanded load diagram. This study overcomes the limitations of the manual engine turbocharger–matching process providing decision support on the effective turbocharger matching to satisfy contradictory objectives

  • A novel methodology for Marine dual fuel Engines sensors diagnostics and health management
    'SAGE Publications', 2021
    Co-Authors: Stoumpos Sokratis, Theotokatos Gerasimos
    Abstract:

    The sensors abnormalities, faults and failure detection and diagnosis for Marine Engines are considered crucial for ensuring the engine safe and smooth operation. The development of such system(s) is typically based on the manufacturers experience on sensors and actuators faults and failure events. This study aims to introduce a novel methodology for the sensors diagnostics and health management in Marine dual fuel Engines by employing a combination of thermodynamic, functional control and data-driven models. The concept of an Engine Diagnostics System (EDS) is developed to provide intelligent engine monitoring, advanced sensors' faults detection as well as timely and profound corrective actions. This system employs a neural networks (NN) Data-Driven (DD) model along with appropriate logic controls. The DD model is set up based on the derived steady state data from a thermodynamic model of high fidelity and is capable of real-time prediction of the engine health condition behaviour. The concept of a novel Unified Digital System (UDS) is proposed that combines the engine's existing control and diagnostic systems and the proposed EDS systems. The functionality of the UDS system is validated by employing a digital twin of the considered Marine dual fuel engine by investigating scenarios for assessing the engine performance that entail abnormalities in the engine's speed and boost pressure sensors. The simulation results demonstrate that the developed UDS is capable of sufficiently capturing the engine's sensors abnormalities and applying appropriate corrective actions to restore the engine operation in its original state. This study benefits the development future systems facilitating the Engines condition assessment and self-correction of the engine sensors' abnormalities, which will be required for smart and autonomous shipping