Exhaust Gas Of Marine Diesel Engine Research Articles

The marine diesel engine exhaust gas temperature baseline model based on particle swarm optimised generalised regression neural network

ABSTRACT This study addresses limitations in traditional condition monitoring for marine diesel engine (MDE) reliability and stability by proposing a hybrid machine learning and deep learning (DL) model called Particle Swarm Optimization-Generalized Regression Neural Network (PSO-GRNN) for real-time exhaust gas temperature (EGT) monitoring. The model integrates Mahalanobis distance (MD) calibration, wavelet packet denoising, and Pearson correlation analysis for comprehensive data preprocessing. Validation is conducted using historical '6L34DF' diesel engine data. Particle Swarm Optimization (PSO) optimizes the spread value (σ) of the Generalized Regression Neural Network (GRNN) to establish an optimal baseline model for EGT prediction. Experimental results show that PSO-GRNN outperforms Backpropagation Neural Network (BPNN), GRNN, Bidirectional Gated Recurrent Unit (BiGRU), Genetic Algorithm- Generalized Regression Neural Network (GA-GRNN), and Deep Belief Network-Support Vector Regression (DBN-SVR) in terms of training time and accuracy, demonstrating its suitability for MDE baseline modeling.

THERMODYNAMIC ANALYSIS AND PAYBACK PERIOD INVESTIGATION OF POWER TURBINE GENERATOR FOR MARINE DIESEL ENGINES

Because of the heat flow and temperature, marine diesel engine exhaust gas energy is by far the highest desirable among the waste heat sources of a ship. Waste heat recovery systems generate electrical power by using this exhaust gas energy. The goal of this study is to measure how much the power turbine generator improves the system's efficiency for 3 different engine loads and 3 different ambient conditions. This study presents a power turbine generator using a six-cylinder low-speed marine diesel engine. Analyses are performed by considering three different ambient conditions and three different diesel engine loads, and the exergy destruction of each component, exergy efficiency, exergy destruction rate, efficiency increases, and power output of the system is calculated. Besides that, the payback period is calculated according to the installation cost of the power turbine generator and the cost of the fuel saved annually. Based on the analysis, the highest power output for the power turbine generator occurred under 100% engine operating load and winter ambient conditions, and the lowest power output occurred under 75% engine operating load and tropical ambient conditions. On the other hand, for the same ambient conditions, the highest efficiency increase occurred at 90% engine operating load, and the lowest efficiency increase occurred at 100% engine operating load. In the power turbine generator, it is observed that the shortest payback period is 100% engine operating load and winter ambient condition.

Study on removing NO from simulated marine diesel engine exhaust gas using the novel composite system of Ozone-Na2SO3/(NH2)2CO

The pollutants from the marine exhaust gas seriously threaten air quality and human health. Wet absorption is one of the most efficient NOx control pathways. The strict emission control regulations require the wet NOx control technology to have high NOx removal efficiency and the nitrate concentration of the absorption solution to be below 60 mg/L. The novel system of ozone-Na2SO3/(NH2)2CO could not only make the NOx absorption efficiency and the amount of nitrate residue fully meet the regulations but also effectively reduce the (NH2)2CO consumption and the nitrite concentration. The final product of NO was mainly N2 instead of nitrate. The effects of O3 concentration, Na2SO3 concentration, (NH2)2CO concentration, O2 concentration, SO2 concentration, initial pH value, and temperature were thoroughly investigated. The experimental results showed that the NOx removal efficiency was mostly influenced by the O3 concentration, Na2SO3 concentration, and the initial pH value. Moreover, the nitrate concentration was mainly controlled by Na2SO3 concentration and initial pH value. While the nitrite concentration was governed by the (NH2)2CO concentration and initial pH value. The increase of O3 concentration and Na2SO3 concentration promote NOx absorption. Although the decrease of initial pH value resulted in a slight increase of nitrate, it greatly reduced the content of nitrite. Furthermore, the increase of Na2SO3 concentration helped to improve the NOx removal efficiency and inhibited the generation of nitrate. Initial pH value was the critical parameter for the NO absorption process. Ozone-Na2SO3/(NH2)2CO composite system showed great application potential in the field of marine wet NOx control technology.

Pollution Control of Exhaust Emissions of Marine Diesel Engines

This paper describes the impact of marine diesel engine exhaust gas on the atmospheric environment and the international control requirements for marine diesel engine emissions internationally; introduces the current technical measures to reduce emissions of diesel engine exhaust pollution. On this basis, the advantages and disadvantages of each measure and the application scopes are explored.

Effect of Wet Scrubbing Oxidation Denitration Technology Combined with Ultraviolet Online Irradiation on the Efficiency of Desulfurization and Denitrification of Ship Exhaust Gas

In order to alleviate the air pollution caused by nitrogen and sulfur oxides discharged from ships, the efficient method of deoxidization and desulfurization of marine diesel engine exhaust gas has been explored. In this study, at present, the mainstream technology of ship exhaust gas removal at home and abroad, wet scrubbing oxidation denitration technology is taken as the research object. Ultraviolet (UV) online irradiation is introduced into the process of wet scrubbing oxidation denitration of NaClO2 solution. The effects of different parameters, such as the concentration of NaClO2, the temperature of washing solution, the concentration of O2 and SO2, on the removal of No are studied. The reaction mechanism is further analyzed. The results show that photochemical reaction will take place between UV online irradiation and NaClO2 solution, resulting in a large number of active radicals with strong oxidation, which can obviously enhance the effect of No removal by wet scrubbing of NaClO2 solution. It can be seen that the wet scrubbing oxidation denitration technology combined with UV online irradiation can greatly improve the efficiency of desulfurization and denitrification of ship's exhaust gas. It is an efficient method of deoxidization and desulfurization of ship's diesel engine exhaust gas, which is of great help to alleviate exhaust gas pollution.

“NaClO2-Sea Water” Wet Denitrification Technology Using NOx Treatment Technology in the Desulfurization and Denitrification of Ship Exhaust Gas

To minimize the emission pollution of nitrogen oxides (NOx) in marine diesel engine exhaust, based on the existing NOx treatment technology, the "NaClO2-sea water" wet denitrification technology was further proposed. The denitrification performance of NaClO2 solution in seawater and NaClO2 solution in fresh water was analyzed by self-designed and built experimental platform. Moreover, the effects of the temperature of the absorption solution, the initial concentration of NaClO2 and the concentration of NO in diesel exhaust gas on the denitrification performance of NaClO2 sea water solution were studied. The experimental results showed that the denitrification rate of NaClO2 solution with seawater as solvent was slightly lower than that of NaClO2 solution with fresh water, but the denitrification duration of seawater solution had obvious advantages over that of fresh water solution. In addition, by increasing the temperature of the absorption solution and the initial concentration of NaClO2 and decreasing the concentration of NO, the denitrification rate of NaClO2 sea water solution was increased. Whereas, if the temperature exceeded a certain limit, the continuous denitrification time of the solution would be decreased. Therefore, “NaClO2-sea water” wet denitrification technology has the advantages of cheap raw materials and long continuous denitrification time. High denitrification efficiency can be achieved by optimizing reaction conditions, so it can be used for denitrification of marine diesel engine exhaust gas.

High Reduction Efficiencies of Adsorbed NOx in Pilot-Scale Aftertreatment Using Nonthermal Plasma in Marine Diesel-Engine Exhaust Gas

An efficient NOx reduction aftertreatment technology for a marine diesel engine that combines nonthermal plasma (NTP) and NOx adsorption/desorption is investigated. The aftertreatment technology can also treat particulate matter using a diesel particulate filter and regenerate it via NTP-induced ozone. In this study, the NOx reduction energy efficiency is investigated. The investigated marine diesel engine generates 1 MW of output power at 100% engine load. NOx reduction is performed by repeating adsorption/desorption processes with NOx adsorbents and NOx reduction using NTP. Considering practical use, experiments are performed for a larger number of cycles compared with our previous study; the amount of adsorbent used is 80 kg. The relationship between the mass of desorbed NOx and the energy efficiency of NOx reduction via NTP is established. This aftertreatment has a high reduction efficiency of 71% via NTP and a high energy efficiency of 115 g(NO2)/kWh for a discharge power of 12.0 kW.

Study on Optimization Simulation of Scr Denitration System for Marine Diesel Engine

Abstract With the rapid development of shipbuilding industry exhaust world is also very harmful one kind of environmental issues, and the ship marine diesel engine exhaust gas is mainly produced, so in recent years it has developed a diesel engine SCR system. SCR system can control emissions of nitrogen oxides in the exhaust of vessel, furthermore air pollution can be reduced. The main goal of article was using fluent software to correct SCR system selection and flue gas flow under different size best deflector arrangement is simulated. Next goal is further optimize the structure of the SCR system.

Nonthermal Plasma System for Marine Diesel Engine Emission Control

A nonthermal plasma reactor (NTPR) using two 2.45-GHz microwave (MW) generators for the abatement of nitrogen oxides ( ${\text {NO}}_{\text {x}}$ ) and sulfur ( ${\text {SO}}_{\text {x}}$ ) contained in the exhaust gas of a 200-kW marine diesel engine was built and tested. Numerical analysis based on a nonthermal plasma kinetics model for the abatement of ${\text {NO}}_{\text{x}}$ and ${\text{SO}}_{\text{x}}$ from marine diesel engine exhaust gas was performed. A generic kinetic model that implements electron collisions and plasma chemistry has been developed for applications involving low-temperature (50–100 K) nonthermal plasma. Abatement efficiencies of ${\text {NO}}_{\text{x}}$ and ${\text {SO}}_{\text{x}}$ were investigated for a range of mean electron energies, which directly impact on the rate constants of electron collisions. The simulation was conducted using the expected composition of exhaust gas from a typical two-stroke, slow-speed marine diesel engine. The simulation results predict that mean electron energy of 0.25–3.2 eV gives abatement efficiency of 99% for ${\text {NO}}_{\text{x}}$ and ${\text {SO}}_{\text{x}}$ . The minimum residence time required was found to be 80 ns for the mean electron energy of 1 eV. Multimode cavity was designed using COMSOL multiphysics. The NTPR performance in terms of ${\text {NO}}_{\text{x}}$ and ${\text {SO}}_{\text{x}}$ removal was experimentally tested using the exhaust from a 2-kW lab scale, two-stroke diesel engine. The experimental results also show that the complete removal of NO is possible with the MW plasma (yellow color) generated. However, it was found that generating required MW plasma is a challenging task and requires further investigation.

Numerical Model of SO2 Scrubbing with Seawater Applied to Marine Engines

Abstract The present paper proposes a CFD model to study sulphur dioxide (SO2) absorption in seawater. The focus is on the treatment of marine diesel engine exhaust gas. Both seawater and distilled water were compared to analyze the effect of seawater alkalinity. The results indicate that seawater is more appropriate than distilled water due to its alkalinity, obtaining almost 100% cleaning efficiency for the conditions analyzed. This SO2 reduction meets the limits of SOx emission control areas (SECA) when operating on heavy fuel oil. These numerical simulations were satisfactory validated with experimental tests. Such data are essential in designing seawater scrubbers and judging the operating cost of seawater scrubbing compared to alternative fuels.

Reduction of NOx and PM in marine diesel engine exhaust gas using microwave plasma

Abatement of NOx and particulate matters (PM) of marine diesel exhaust gas using microwave (MW) non-thermal plasma is presented in this paper. NOx mainly consist of NO and less concentration of NO2 in a typical two stoke marine diesel engine and microwave plasma generation can completely remove NO. MW was generated using two 2kW microwave sources and a saw tooth passive electrode. Passive electrode was used to generate high electric field region within microwave environment where high energetic electrons (1-3eV) are produced for the generation of non-thermal plasma (NTP). 2kW gen-set diesel exhaust gas was used to test our pilot-scale MW plasma reactor. The experimental results show that almost 100% removal of NO is possible for the exhaust gas flow rate of 60l/s. It was also shown that MW can significantly remove soot particles (PM, 10nm to 365nm) entrained in the exhaust gas of 200kW marine diesel engine with 40% engine load and gas flow rate of 130l/s. MW without generating plasma showed reduction up to 50% reduction of PM and with the plasma up to 90% reduction. The major challenge in these experiments was that igniting the desired plasma and sustaining it with passive electrodes for longer period (10s of minutes) as it required fine tuning of electrode position, which was influenced by many factors such as gas flow rate, geometry of reactor and MW power.

A Short Review of Treatment Methods of Marine Diesel Engine Exhaust Gases

Marine diesel engine mainly use heavy fuel oil with high-sulfur as fuel, making its main pollutants become nitrogen oxides(NOX), sulfur oxides(SOX) and particulate matters(PM). It's urgent to reduce the pollutants using advanced technology. Herein, we reviewed the treatment methods of marine diesel engine exhaust gas, especially for NOX and PM treatment.

Pilot-Scale Aftertreatment Using Nonthermal Plasma Reduction of Adsorbed NOx in Marine Diesel-Engine Exhaust Gas

Regulations governing marine diesel engine NOx emissions have recently become more stringent. As it is difficult to fulfill these requirements by combustion improvements alone, effective aftertreatment technologies are needed to achieve efficient NOx reductions. In this study, we develop an effective NOx-reduction aftertreatment system for a marine diesel engine that employs combined nonthermal plasma (NTP) and adsorption. Compared with selective catalytic reduction, the proposed technology offers the advantages of not requiring a urea solution or harmful heavy-metal catalysts and low operating temperatures of less than 150 °C. The NOx reduction comprises repeated adsorption and desorption flow processes using NTP combined with NOx adsorbents made of MnOx–CuO. High concentrations of NOx are treated by NTP after NOx adsorption and desorption, and this aftertreatment system demonstrates excellent energy efficiencies of 161 g(NO2)/kWh, which fulfills the most recent International Maritime Organization emission NOx standards in the Tier II–III regulations for 2016 and requires only 4.3 % of the engine output power.

A New Drying Room Heated by Marine Diesel Engine Exhaust Gas

To recycle the waste heat in the exhaust gas of marine diesel engine, a new drying room heated by marine diesel engine exhaust gas is introduced. The drying room`s structure, working principle and the main design parameters calculating methods is designed. Comparing to the traditional heating methods, this kind of drying room make full use of the heat energy and will acquire huge economic benefits.

New Technologies for Marine Diesel Engine Emission Control

Atmospheric emissions of pollutants from marine diesel engines fuelled with heavy fuel oils contribute significantly to environmental pollution. To limit the presence of such pollutants in the environment, the International Maritime Organization recently introduced specific regulations to control SO2, NOx and particulate concentrations in exhaust gases. This paper is a short communication on two innovative techniques for marine diesel engine exhaust gas cleaning: the Electrostatic Seawater Scrubbing and the Electron Beam/Microwave Non-Thermal Plasma. These technologies are developed within the EFP7 DEECON (Innovative After-Treatment System for Marine Diesel Engines Emission Control) project and are able to provide State-of-the-Art removal of SO2 and NOx, together with a significant removal of Volatile Organic Compounds and Diesel Particulate Matter, which are among the most toxic pollutants emitted by ships and are currently excluded in the regulations due to the absence of reliable technologies for their removal. Preliminary experimental and modelling results on the treatment of model diesel exhaust gas are reported.

Experimental Results of a Combined DBD Reactor-Catalyst Assembly for a Direct Marine Diesel-Engine Exhaust Treatment

This paper gives an overview of a robust dielectric barrier discharge reactor-catalyst construction used in a bypass of a marine diesel-engine exhaust gas system. Electrode arrangement, housing, and electrode positioning systems are discussed allowing for high temperature and reasonable vibration operation. Preliminary test results are given considering the chemical reactions, particulate matter, and CO and HC reductions. An operative removal efficiency up to 99 percent is obtained (relative percentage units with respect to initial maximal concentrations). The basics of power supply construction and output waveforms are given.

Development of Clean Diesel Engine with Plasma-Assisted Aftertreatment System (Achievement of System Energy Efficiency of 385 g (NO<sub>2</sub>)/kWh Using Nonthermal Plasma and EGCR)

The authors realize a new prototype of plasma-assisted environmental protection aftertreatment system using atmospheric-pressure nonthermal plasma combine processes for super clean diesel engines. This system does not use any rare or precious metal catalysts and harmful ammonia or urea solution. A NOx aftertreatment system, using nonthermal plasma (NTP) reduction and exhaust gas components recirculation, is investigated. A pilot-scale system is applied to a stationary diesel engine using A type of heavy oil fuel. In this system, NOx is first removed by adsorption, and subsequently, the adsorbent is regenerated by thermal desorption. The desorbed high-concentration NOx is reduced by using nitrogen NTP with low flow rate. Moreover, NOx re-circulated into the engine intake reduces NOx emission. In the present experiments, a very high system energy efficiency of 385 g (NO2)/kWh is achieved in the NOx reduction test. The developed system demonstrates excellent energy efficiencies to meet the most recent international regulation of marine diesel engine exhaust gas.

Seawater scrubbing desulfurization: A model for SO2 absorption in fall‐down droplets

AbstractAn unsteady model of SO2 absorption in fall‐down spherical seawater droplets is presented, focused on marine diesel engine exhaust gas scrubbing. The model evaluates the amount of sulfur dioxide absorbed by a single droplet, with given initial velocity, diameter, and alkalinity, falling counter‐flow with respect to the exhaust gas stream. Kinematics of the droplet, heat exchange, and evaporation has been considered, taking into account internal circulation. Neutralization of absorbed sulfur species in the droplet has been modeled with a global and fast reaction mechanism. Transport equations for species inside the droplet have been solved on a nonuniform computational grid, which is regenerated at every time step to account for droplet diameter reduction. The single‐droplet model has been incorporated in a simple scrubber plug‐flow model, to evaluate the desulfurization efficiency and the seawater supply rate under realistic marine engine exhaust gas desulfurization conditions. The influence of flue gas inlet temperature, flue gas velocity, initial droplet size, and velocity on the scrubbing process were investigated. Results of this model are valuable for judging the feasibility and operating costs of this SO2 scrubbing technique compared with alternative methods. © 2011 American Institute of Chemical Engineers Environ Prog, 2011

1727 内航船エンジン排ガス浄化用の新しい脱硝触媒システムの研究

New purification technology of the nitrogen oxide discharged from vessels, such as a small coaster, was developed. A new de-NOx system by the combination of an "adsorbent-selective reduction catalyst" was studied as a method of solving the problem that a former type SCR catalyst does not fully operate on the conditions that the exhaust gas temperature is low (below 300℃). Mn-Zr oxide was effective in removing NO at 100-300℃ by absorption in the solid as nitrate. Nitrogen oxides were first stored in the Mn-Zr oxide below 300℃. Then, the stored NOx was released above 300℃ and reduced by the SCR catalyst in the down-stream. As a result of the purification examination using marine diesel engine exhaust gas, it was found that 80% of NOx discharged in a low-temperature region was removable by this system.