• Journal of Environmental Impact Assessment
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• v.6 no.2
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• pp.93-102
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• 1997

Acid rain below pH 5.6 is responsible for 40% of annual precipitation in Korea and it is more serious especially in major cites. Because of that, it is urgent to make measures to reduce the emission of $SO_2$, one of the major air pollutants causing acid rain. The national total emission of $SO_2$ in 1994 was estimated as 1.6 million tons. The $SO_2$ emission in 2020, is expected to increase up to 3.2 million tons, about 2 times that of 1994 under Business-As-Usual scenario. We could take various $SO_2$ reduction measures such as installing desulfurization facilities, the supply of low-sulfur oil and clean fuel(LNG), energy savings, upgrading of production process. However, it is necessary to check the economic feasibility and the attainability to reduction target with a dynamic optimization mode, "Global 2100 Model". The cost-benefit analyses for the measures using the revised "Global 2100 Model" clearly revealed that the desulfurization facilities should be introduced to reduce the $SO_2$ concentration to 0.01 ppm with fuel substitution. If the introduction of desulfurization facilities is delayed, We can not attain the goal of Ministry of Environment before the year of 2012, even in the case that almost all the fuels would be substituted with LNG.

• Journal of Environmental Science International
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• v.13 no.4
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• pp.339-347
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• 2004

This paper asks the question: what choice of environmental policy instruments is efficient to reduce sulfur dioxide from stationary sources\ulcorner: In Korea, command and control has been a common way of controlling $SO_2-emissions.$ When compared to the non-incentive environmental policy instrument such as command and control, economic incentive environmental policy instrument has been the advantage of making polluter himself flexibly deals with in marginal abatement cost to develop environmental technology in the long view. Therefore, the application possibility of the incentive environmental policy instrument was studied in this research to realize the countermeasure for controlling of $SO_2-emissions.$ As a result, enforcement of the countermeasure such as flue gas desulfurizer by command and control would be suitable because power generation is performed by the public or for the public in source of air pollution and thus, economic principle is not applied to the polluter. In the source of industrial pollution, enforcement of fuel tax is found to be suitable for the countermeasure for the use of low sulfur oil in terms of the flexibility of demand for the price in the long tenn. For the permissible air pollution standards applicable to all air pollutant emitting facilities, enforcement of incentive environmental policy such as bubble, off-set, banking policy or tradeable emission penn its would be ideal in long terms according to the regional characteristics and the number and scale of air pollutant emitting facilities.

• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.226-233
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• 2023

To create an environmentally sustainable fuel with a low sulfur concentration, requires alternative sulfur removal methods. During the course of this study, a high surface gamma alumina-supported ZnO nanocatalyst with a ZnO/-Al₂O₃ ratio of 12% was developed and tested for its ability to improve the activity of the oxidative desulfurization (ODS) process for the desulfurization of kerosene fuel. Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) were used to characterize the produced nanocatalyst. In a digital batch baffled reactor (20~80 min), the effectiveness of the synthesized nanocatalyst was tested at different initial concentrations of dibenzothiophene (DBT) of 300~600 ppm, oxidation temperatures (25~70 ℃), and oxidation periods (0.5, 1, and 2 hours). The baffles included in the digital baffled batch reactor resist the swirling of the reaction mixture, thus facilitating mixing. The ODS procedure yielded the maximum DBT conversion (95.5%) at 70 ℃ with an 80-minute reaction time and an initial DBT level of 600 ppm. The most precise values of kinetic variables were subsequently determined using a mathematical modelling procedure for the ODS procedure. The average absolute error of the simulation findings was less than 5%, demonstrating a good degree of agreement with the experimental results acquired from all runs. The optimization of the operating conditions revealed that 99.1% of the DBT can be removed in 140 minutes.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.3
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• pp.451-458
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• 2022

In Korea, five major ports have been designated as sulfur oxide emission control areas to reduce air pollutant emissions, in accordance with Article 10 of the "Special Act on Port Air Quality" and Article 32 of the "Ship Pollution Prevention Regulations". As regulations against vessel-originated air pollutants (such as PM, CO2, NOx, and SOx) have been strengthened, the Ministry of Oceans and Fisheries(MOF) enacted rules that newly built public ships should adopt eco-friendly propulsion systems. However, particularly in diesel-electric hybrid propulsion systems,the demand for precise control schemes continues to grow as the fuel saving rate significantly varies depending on the control strategy applied. The conventional Power Take In-Power Take Off(PTI - PTO) mode control adopts a rule-based strategy, but this strategy is applied only in the low-load range and PTI mode; thus, an additional method is required to determine the optimal fuel consumption point. The proposed control method is designed to optimize fuel consumption by applying the equivalent consumption minimization strategy(ECMS) to the PTI - PTO mode by considering the characteristics of the specific fuel oil consumption(SFOC) of the engine in a diesel-electric hybrid propulsion system. To apply this method, a specific fishing vessel model operating on the Korean coast was selected to simulate the load operation environment of the ship. In this study, a 10.2% reduction was achieved in the MATLAB/SimDrive and SimElectric simulation by comparing the fuel consumption and CO2 emissions of the ship to which the conventional rule-based strategy was applied and that to which the ECMS was applied.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.2
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• pp.240-245
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• 2016

This paper describes the rheological behavior study such as viscosity and change of shear stress regarding marine lubricating oil according to the amount of Marine Gas Oil (MGO) dilution. The viscosity reduction due to fuel dilution is crucially important characteristic to decreasing engine durability because of the abrasion of piston ring or liner. The lubricating oil used in this paper was blended with magnetic stirrer diluted High Sulfur Diesel (HSD, 0.05 wt%) ratio of 3 %, 6 %, 10 %, 15 % and 20 %. The viscosity and shear stress of diluted lubricating oil were measured with the temperature range from $-10^{\circ}C$ to $80^{\circ}C$ using a rotary viscometer (Brookfield Viscometer). As the amount of MGO dilution increasing in lubricating oil, the viscosity and stress of those decreased, because the lubricating oil diluted MGO with low viscosity show the trends to decreased viscosity and shear stress. Especially, the viscosity and shear stress of lubricating oil radically decreased at low temperature ($0{\sim}-10^{\circ}C$) and doesn't effect in MGO dilution at over $40^{\circ}C$. As temperature risen, the reduction of the viscosity and shear stress in lubricating oil shows the Newtonian behavior. The lubricating oil was required to check up periodically to improve engine durability since the viscosity reduction by MGO dilution accelerating the engine abrasion.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.809-818
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• 2019

Since January 1, 2020, the International Maritime Organization (IMO) has put in place strong regulations to reduce air pollution caused by ships by lowing the upper limit of ship fuel oil sulfur content from 3.5% to 0.5% for ships passing through all sea areas around the world. Although it is important to reduce air pollutants by using fuel oil with low sulfur content, reducing the amount of energy waste through the economic operation of a ship can also help reduce air pollutants. Ships can follow designated routes accurately even under the influence of noise using autopilot systems. However, regardless of their quality, the performance of these systems is af ected by noise; heading angles with added measurement noise from the gyroscope are input into the autopilot system and degrade its performance. A technique to solve these problems reduces noise effects through the application of a Kalman filter, which is widely used in condition estimation. This method, however, cannot completely eliminate the effects of noise. Therefore, to further improve noise removal performances, in this study we propose a better denoising method than the Kalman filter technique by applying a multi-layer perceptron (MLP) in forward direction motion and a Kalman Filter in rotation motion. Simulations show that the proposed method improves forward direction motion by preventing the malfunction of a rudder more so than merely using a Kalman Filter.

• The Korean Journal of Petroleum Geology
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• v.14 no.1
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• pp.45-52
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• 2008

The GTL(Gas to Liquids) technology, manufacturing synthesized oil from natural gas, had been developed about 1920 for the military purpose by Fischer and Tropsch, German scientists. And 1960, Sasol company had started commercializing the FT(Fischer-Tropsch) synthesis technology, for the transport fuel in South Africa. Until a recent date, the commercialization of GTL technology had been delayed by low oil price. But concern about depletion of petroleum resources, and development in synthesizing technology lead to spotlight on the GTL businesses. Especially, Qatar, which has rich natural gas fields, aims at utilizing natural gas like conventional oil resources. Therefore, around this nation, GTL plants construction has been promoted. There are mainly 3 processes to make GTL products(Diesel, Naphtha, lube oil, etc) from natural gas. The first is synthesis gas generation unit reforming hydrogen and carbomonoxide from natural gas. The second is FT synthesis unit converting synthesized gas to polymeric chain-hydrocarbon. The third is product upgrading unit making oil products from the FT synthesized oil. There are quite a little sulfur, nitrogen, and aromatic compounds in GTL products. GTL product has environmental premium in discharging less harmful particles than refinery oil products from crude to the human body. In short, the GTL is a clean technology, easier transportation mean, and has higher stability comparing to LNG works.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.152-156
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• 1987

A mixed population of marine bacteria was obtained to catalize the biodegradation of bunker-C fuel oil by means of the enrichment culture technique. Samples used for the enrichment culture were collected from sea water and sediments in the vicinity of Pusan, Chungmu, and Ulsan in Korea. As the biodegradation of bunker-C oil proceeded, the number of bacteria increased from $1.1\times10^6\;to\;8.7\times10^8$ cells per ml when pH was bufferized by 0.1 M Tris-HCl buffer to 7.6, then oil dispersion increased to $OD^{540}$ 2.2 and approximately $48\%$ of the oil was biodegradated in 10 days. Oil dispersion was absolutely dependent on the addition of nitrogen and phosphate sources in sea water. High and low sulfur-containing bunker-C and crude oil could be dispersed similarly. Bunker-C oil was dispersed rapidly at the pH ranging from 7.0 to 8.0 and dispersed to the amount of 7.5 g per liter of sea water medium.

• Clean Technology
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• v.23 no.2
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• pp.140-147
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• 2017

In this study, we performed numerical simulation for the catalyst regeneration process of diesel desulfurization reactor. We analyzed the changes in regeneration process according to purge gas flow rate, catalyst permeability, reactor size, and heat loss of reactor. We have found that the regeneration process is very much affected by temperature changes whereas it is hardly affected by catalyst permeability and porosity. We also estimated the regeneration time according to purge gas flow rate and initial temperatures and have found that increasing purge gas temperature is more effect for fast regeneration. The present results can be utilized to design a regeneration process of diesel desulfurization reactor for a fuel cell used in ships. Furthermore, the present work also can be used to design low sulfur diesel supply in oil refineries and therefore contribute to the development of clean petrochemical technology.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.76-86
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• 2018

Using the CAPSS emissions data, we analysed changes and reasons in the annual air pollutant emission trends from 1999 to 2014. The CO emissions in the metropolitan area decreased steadily since 2001, when the latest model year of automobiles and high efficiency fuel were applied. However, other regions have not changed significantly in annual emissions. $NO_x$ emissions continued to increase since 2003, and unchanged after the decline in 2007. $SO_x$ emissions are steadily declining due to the supply of low sulfur oil. The $PM_{10}$ and $PM_{2.5}$ emissions were repeatedly affected by the influence of motor vehicles activities in the metropolitan area. In Gangwon and Chungcheong Provinces, emissions are increasing according to the use of coal in the manufacturing sector. And VOC and $NH_3$ emissions are increasing steadily every year. The major CO emission sources was automobiles in the metropolitan area. However, agricultural residue burning was the biggest CO sources in the Chungchong, Honam and Yeongnam Provinces. The major sources of $NO_x$ emissions differ from region to region. In the Metropolitan area, Honam and Yeongnam region, the truck was the largest emitter of $NO_x$. However, the cement kiln was the largest producer of $NO_x$ in Gangwon region, and the power plant is the largest emitter in Chungcheong Provinces.