scholarly journals Possibilities of Ammonia as Both Fuel and NOx Reductant in Marine Engines: A Numerical Study

2022 ◽  
Vol 10 (1) ◽  
pp. 43
Author(s):  
Carlos Gervasio Rodríguez ◽  
María Isabel Lamas ◽  
Juan de Dios Rodríguez ◽  
Amr Abbas
Keyword(s):  
Carbon Dioxide ◽  
Numerical Study ◽  
Dual Fuel ◽  
Oxides Of Nitrogen ◽  
Marine Engines ◽  
Marine Diesel ◽  
Important Challenge ◽  
Climate Neutrality ◽  
Diesel Operation ◽  
Ammonia Injection

Nowadays, the environmental impact of shipping constitutes an important challenge. In order to achieve climate neutrality as soon as possible, an important priority consists of progressing on the decarbonization of marine fuels. Free-carbon fuels, used as single fuel or in a dual-fuel mode, are gaining special interest for marine engines. A dual fuel ammonia-diesel operation is proposed in which ammonia is introduced with the intake air. According to this, the present work analyzes the possibilities of ammonia in marine diesel engines. Several ammonia-diesel proportions were analyzed, and it was found that when the proportion of ammonia is increased, important reductions of carbon dioxide, carbon monoxide, and unburnt hydrocarbons are obtained, but at the expense of increments of oxides of nitrogen (NOx), which are only low when too small or too large proportions of ammonia are employed. In order to reduce NOx too, a second ammonia injection along the expansion stroke is proposed. This measure leads to important NOx reductions.

NUMERICAL STUDY ON NOX EMISSION REDUCTION MECHANISM OF HCCI MARINE DIESEL ENGINE FOR IMO TIER III EMISSION LIMITS

2021 ◽  
Vol 159 (A2) ◽  
Author(s):  
B Li ◽  
H T Gao
Keyword(s):  
Diesel Engine ◽  
Emission Reduction ◽  
Numerical Study ◽  
Combustion Process ◽  
Reduction Rate ◽  
Marine Diesel Engine ◽  
Oxides Of Nitrogen ◽  
Nox Formation ◽  
Marine Diesel ◽  
Main Component

With the advantages of ultra-low emissions of oxides of nitrogen (NOX) and high thermal efficiency, the homogeneous charge compression ignition (HCCI) mode applied to marine diesel engine is expected to be one of the technical solutions to meet the International Maritime Organization (IMO) MARPOL73/78 Convention-Annex VI Amendment Tier III requirement. According to the NOX chemical reaction mechanism, taking a marine diesel engine as the application object, the numerical study on the NOX formation characteristics of n-heptane for HCCI combustion process is performed. The results indicate that NO is usually the main component in the generation and emissions of NOX with the n-heptane HCCI mode. The combustor temperature plays more important role in the proportion of NO generation and emission. Compared with the experimental data of conventional marine diesel engine, the emission reduction rate of NOX can achieve an average of more than 95% in using HCCI technology.

Numerical Study on NOx Emission Reduction Mechanism of HCCI Marine Diesel Engine for IMO Tier III Emission Limits

2017 ◽  
Vol Vol 159 (A2) ◽  
Author(s):  
B Li ◽  
H T Gao
Keyword(s):  
Diesel Engine ◽  
Emission Reduction ◽  
Numerical Study ◽  
Combustion Process ◽  
Reduction Rate ◽  
Marine Diesel Engine ◽  
Oxides Of Nitrogen ◽  
Nox Formation ◽  
Marine Diesel ◽  
Main Component

With the advantages of ultra-low emissions of oxides of nitrogen (NOX) and high thermal efficiency, the homogeneous charge compression ignition (HCCI) mode applied to marine diesel engine is expected to be one of the technical solutions to meet the International Maritime Organization (IMO) MARPOL73/78 Convention-Annex VI Amendment Tier III requirement. According to the NOX chemical reaction mechanism, taking a marine diesel engine as the application object, the numerical study on the NOX formation characteristics of n-heptane for HCCI combustion process is performed. The results indicate that NO is usually the main component in the generation and emissions of NOX with the n-heptane HCCI mode. The combustor temperature plays more important role in the proportion of NO generation and emission. Compared with the experimental data of conventional marine diesel engine, the emission reduction rate of NOX can achieve an average of more than 95% in using HCCI technology.

A Numerical Study on Combustion and Emissions in a Dual Fuel Directly Injected Engine Using Biogas and Diesel

2014 ◽  
Author(s):  
Akshit Dewan ◽  
Bassem H. Ramadan ◽  
Craig Hoff
Keyword(s):  
Carbon Dioxide ◽  
Fuel Injection ◽  
Numerical Study ◽  
Engine Performance ◽  
Dual Fuel ◽  
Carbon Dioxide Content ◽  
Mixture Ratio ◽  
Human Waste ◽  
Pilot Fuel ◽  
Expected Benefits

A numerical study on the use of biogas and diesel in a dual-fueled directly-injected engine has been conducted. The objective of this study is to determine the effect of using biogas on engine performance, combustion, and emissions. The main fuel is biogas which is premixed with air in order to form a homogeneous mixture. The mixture is then compressed and ignited by injecting diesel fuel before TDC. The pilot fuel is expected to lead to multiple ignition points in the cylinder in order to achieve uniform combustion in the cylinder. The expected benefits are lower nitrogen oxides and soot compared to pure diesel combustion. Numerical simulations using CFD software were used to simulate fuel-air mixture, compression, fuel injection, combustion, and emissions. Different quantities of biogas and diesel were investigated to determine the optimum mixture ratio. Since biogas, which is natural gas produced from human waste, contains large quantities of carbon dioxide, the effect of carbon dioxide content in the fuel was investigated. The results of this study agree very well with results from other studies found in the literature.

scholarly journals Analysis of the Pre-Injection System of a Marine Diesel Engine Through Multiple-Criteria Decision-Making and Artificial Neural Networks

2021 ◽  
Vol 28 (4) ◽  
pp. 88-96
Author(s):  
C.G. Rodriguez ◽  
M.I. Lamas ◽  
J.D. Rodriguez ◽  
A. Abbas
Keyword(s):  
Decision Making ◽  
Multiple Criteria Decision Making ◽  
Multiple Criteria ◽  
Injection System ◽  
Marine Diesel Engine ◽  
Oxides Of Nitrogen ◽  
Marine Engines ◽  
Marine Diesel ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

Abstract The present work proposes several pre-injection patterns to reduce nitrogen oxides in the Wärtsilä 6L 46 marine engine. A numerical model was carried out to characterise the emissions and consumption of the engine. Several pre-injection quantities, durations, and starting instants were analysed. It was found that oxides of nitrogen can be noticeably reduced but at the expense of increasing consumption as well as other emissions such as carbon monoxide and hydrocarbons. According to this, a multiple-criteria decision-making (MCDM) model was established to select the most appropriate parameters. Besides, an artificial neural network (ANN) was developed to complement the results and analyse a huge quantity of alternatives. This hybrid MCDM-ANN methodology proposed in the present work constitutes a useful tool to design new marine engines.

scholarly journals Numerical Study of Engine Performance and Emissions for Port Injection of Ammonia into a Gasoline\Ethanol Dual-Fuel Spark Ignition Engine

2021 ◽  
Vol 11 (4) ◽  
pp. 1441
Author(s):  
Farhad Salek ◽  
Meisam Babaie ◽  
Amin Shakeri ◽  
Seyed Vahid Hosseini ◽  
Timothy Bodisco ◽  
...  
Keyword(s):  
Numerical Study ◽  
Combustion Process ◽  
Engine Performance ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Dual Fuel ◽  
Spark Ignition Engines ◽  
Performance And Emissions ◽  
Hc Emissions

This study aims to investigate the effect of the port injection of ammonia on performance, knock and NOx emission across a range of engine speeds in a gasoline/ethanol dual-fuel engine. An experimentally validated numerical model of a naturally aspirated spark-ignition (SI) engine was developed in AVL BOOST for the purpose of this investigation. The vibe two zone combustion model, which is widely used for the mathematical modeling of spark-ignition engines is employed for the numerical analysis of the combustion process. A significant reduction of ~50% in NOx emissions was observed across the engine speed range. However, the port injection of ammonia imposed some negative impacts on engine equivalent BSFC, CO and HC emissions, increasing these parameters by 3%, 30% and 21%, respectively, at the 10% ammonia injection ratio. Additionally, the minimum octane number of primary fuel required to prevent knock was reduced by up to 3.6% by adding ammonia between 5 and 10%. All in all, the injection of ammonia inside a bio-fueled engine could make it robust and produce less NOx, while having some undesirable effects on BSFC, CO and HC emissions.

scholarly journals Optimization of automatic control of the speed of rotation of a marine diesel engine

2021 ◽  
Vol 27 (1) ◽  
pp. 03-21
Author(s):  
Сергей Иванович Горб ◽  
◽  
Екатерина Яцык
Keyword(s):  
Diesel Engine ◽  
Rotational Speed ◽  
Optimality Criterion ◽  
Factor Space ◽  
Established Method ◽  
Tuning Parameters ◽  
Local Extrema ◽  
Marine Engines ◽  
Marine Diesel ◽  
Speed Stability

Annotation – The well-established method of tuning the speed governors (SG) of diesel engines during their operation under conditions of step disturbances, which are characteristic of diesel-generators, cannot be used for the main marine engines, the dynamic modes of which are associated, first of all, with heavy seas, because disturbances cannot change stepwise both along the channel for setting the rotational speed and along the load channel. In this regard, the practical need for the development of a method for tuning the SG of the main engines, which takes into account the peculiarities of their operation in heavy seas, has been determined. The study simulates the automatic speed control system (ASC) of the main marine engine HYUNDAI – MAN B&W 6G70ME-C9.2 of the large crude carrier "GOLDWAY" with the AutoChief 600 electronic SG. The minimum of instability of the controlled parameter was used as an optimality criterion, i.e. the amplitude of the oscillations of the rotational speed of the diesel engine shaft, with the most probable values of the amplitude and period of oscillations (rolling) of the disturbing effect. The study has established that changing the tuning parameters of the governor may lead to local extrema of the optimality criterion when using an electronic governor in the ACS in the factor space of disturbances on a diesel engine, which are typical for heavy seas. It means that the task, requiring finding local extrema using specialized methods, can be set when using an electronic governor in the ACS. However, a significant decrease in the instability of the rotational speed was achieved by carrying out a simple enumeration of the tuning parameters of the SG. It was also found that with a "heavy" propeller, the rotational speed stability can be increased by decreasing the proportional gain, as well as increasing the integrator time.

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