scholarly journals Numerical Model of SO2 Scrubbing with Seawater Applied to Marine Engines

2016 ◽  
Vol 23 (2) ◽  
pp. 42-47 ◽  
Author(s):  
M. I. Lamas ◽  
C. G. Rodríguez ◽  
J. D. Rodríguez ◽  
J. Telmo

AbstractThe 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 SO2reduction meets the limits of SOxemission 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.

Author(s):  
Akili D. Khawaji ◽  
Jong-Mihn Wie

The most popular method of controlling sulfur dioxide (SO2) emissions in a steam turbine power plant is a flue gas desulfurization (FGD) process that uses lime/limestone scrubbing. Another relatively newer FGD technology is to use seawater as a scrubbing medium to absorb SO2 by utilizing the alkalinity present in seawater. This seawater scrubbing FGD process is viable and attractive when a sufficient quantity of seawater is available as a spent cooling water within reasonable proximity to the FGD scrubber. In this process the SO2 gas in the flue gas is absorbed by seawater in an absorber and subsequently oxidized to sulfate by additional seawater. The benefits of the seawater FGD process over the lime/limestone process and other processes are; 1) The process does not require reagents for scrubbing as only seawater and air are needed, thereby reducing the plant operating cost significantly, and 2) No solid waste and sludge are generated, eliminating waste disposal, resulting in substantial cost savings and increasing plant operating reliability. This paper reviews the thermodynamic aspects of the SO2 and seawater system, basic process principles and chemistry, major unit operations consisting of absorption, oxidation and neutralization, plant operation and performance, cost estimates for a typical seawater FGD plant, and pertinent environmental issues and impacts. In addition, the paper presents the major design features of a seawater FGD scrubber for the 130 MW oil fired steam turbine power plant that is under construction in Madinat Yanbu Al-Sinaiyah, Saudi Arabia. The scrubber with the power plant designed for burning heavy fuel oil containing 4% sulfur by weight, is designed to reduce the SO2 level in flue gas to 425 ng/J from 1,957 ng/J.


2010 ◽  
Author(s):  
Herbert Roeser ◽  
Dilip Kalyankar

Ships are an integral part of modern commercial transport, leisure travel, and military system. A diesel engine was used for the first time for the propulsion of a ship sometime in the 1910s and has been the choice for propulsion and power generation, ever since. Since the first model used in ship propulsion, the diesel engine has come a long way with several technological advances. A diesel engine has a particularly high thermal efficiency. Added to it, the higher energy density of the diesel fuel compared to gasoline fuel makes it inherently, the most efficient internal combustion engine. The modern diesel engine also has a very unique ability to work with a variety of fuels like diesel, heavy fuel oil, biodiesel, vegetable oils, and several other crude oil distillates which is very important considering the shortage of petroleum fuels that we face today. In spite of being highly efficient and popular and in spite of all the technological advances, the issue of exhaust gas emissions has plagued a diesel engine. This issue has gained a lot of importance since 1990s when IMO, EU, and the EPA came up with the Tier I exhaust gas emission norms for the existing engine in order to reduce the NOx and SOx. Harsher Tier II and Tier III norms were later announced for newer engines. Diesel fuels commonly used in marine engines are a form of residual fuel, also know as Dregs or Heavy Fuel Oil and are essentially the by products of crude oil distillation process used to produce lighter petroleum fuels like marine distillate fuel and gasoline. They are cheaper than marine distillate fuels but are also high in nitrogen, sulfur and ash content. This greatly increases the NOx and SOx in the exhaust gas emission. Ship owners are trapped between the need to use residual fuels, due to cost of the large volume of fuel consumed, in order to keep the operation of their ships to a competitive level on one hand and on the other hand the need to satisfy the stringent pollution norms as established by the pollution control agencies worldwide. Newer marine diesel engines are being designed to meet the Tier II and Tier III norms wherever applicable but the existing diesel engine owners are still operating their engines with the danger of not meeting the applicable pollution norms worldwide. Here we make an effort to look at some of the measure that the existing marine diesel engine owners can take to reduce emissions and achieve at least levels prescribed in Tier I. Proper maintenance and upkeep of the engine components can be effectively used to reduce the exhaust gas emission. We introduced a pilot program on diesel engine performance monitoring in North America about two years ago and it has yielded quite satisfying results for several shipping companies and more and more ship owners are looking at the option of implementing this program on their ships.


2020 ◽  
Vol 20 (3) ◽  
pp. 1549-1564 ◽  
Author(s):  
Fan Zhang ◽  
Hai Guo ◽  
Yingjun Chen ◽  
Volker Matthias ◽  
Yan Zhang ◽  
...  

Abstract. Studies of detailed chemical compositions in particles with different size ranges emitted from ships are in serious shortage. In this study, size-segregated distributions and characteristics of particle mass, organic carbon (OC), elemental carbon (EC), 16 EPA polycyclic aromatic hydrocarbons (PAHs) and 25 n-alkanes measured aboard 12 different vessels in China are presented. The results showed the following. (1) More than half of the total particle mass, OC, EC, PAHs and n-alkanes were concentrated in fine particles with aerodynamic diameter (Dp) < 1.1 µm for most of the tested ships. The relative contributions of OC, EC, PAH and alkanes to the size-segregated particle mass are decreasing with the increase in particle size. However, different types of ships showed quite different particle-size-dependent chemical compositions. (2) In fine particles, the OC and EC were the dominant components, while in coarse particles, OC and EC only accounted for very small proportions. With the increase in particle size, the OC / EC ratios first decreased and then increased, having the lowest values for particle sizes between 0.43 and 1.1 µm. (3) Out of the four OC fragments and three EC fragments obtained in thermal–optical analysis, OC1, OC2 and OC3 were the dominant OC fragments for all the tested ships, while EC1 and EC2 were the main EC fragments for ships running on heavy fuel oil (HFO) and marine-diesel fuel, respectively; different OC and EC fragments presented different distributions in different particle sizes. (4) The four-stroke low-power diesel fishing boat (4-LDF) had much higher PAH emission ratios than the four-stroke high-power marine-diesel vessel (4-HMV) and two-stroke high-power heavy-fuel-oil vessel (2-HHV) in fine particles, and 2-HHV had the lowest values. (5) PAHs and n-alkanes showed different profile patterns for different types of ships and also between different particle-size bins, which meant that the particle size should be considered when source apportionment is conducted. It is also noteworthy from the results in this study that the smaller the particle size, the more toxic the particle was, especially for the fishing boats in China.


Author(s):  
Tatsuro Tsukamoto ◽  
Kenji Ohe ◽  
Hiroshi Okada

In these years, a problem of air pollution in a global scale becomes a matter of great concern. In such social situation, diesel engines are strongly required to reduce the NOx and particulate emission in the exhaust gas. In this paper, measurements of particulate emissions from a low speed two-stroke marine diesel engine were conducted with several kinds of diesel oil and a heavy fuel oil, to know the characteristics of particulate emissions at the present situation. The effects of engine load and sulfur content of the fuel on the particulate emission have been examined. The particulate emission from the test engine was measured by partial-flow dilution tunnel system, and particulate matter collected on the filter was divided into four components, SOF (soluble organic fraction), sulfate, bound water and dry soot, by Soxlet extraction and ion chromatograph. Results show that the particulate emission from the test engine operated with heavy fuel oil is three times as much as the value with diesel oil and that not only sulfate but SOF and dry soot concentration increase with the increase in fuel sulfur content. It is also found that the conversion rate from sulfur in fuel into sulfate in particulate matter is nearly independent of the sulfur content in the fuel and increases with the increase in the engine load.


Fuel ◽  
2014 ◽  
Vol 115 ◽  
pp. 145-153 ◽  
Author(s):  
Nikolaos Stamoudis ◽  
Christos Chryssakis ◽  
Lambros Kaiktsis

2021 ◽  
Author(s):  
Marcin Zacharewicz ◽  
Tomasz Kniaziewicz

The paper presents the results of model and empirical tests conducted for a marine diesel engine fueled by a blend of n-butanol and diesel oil. The research were aimed at assessing the usefulness of the proprietary diesel engine model in conducting research on marine engines powered by alternative fuels to fossil fuels. The authors defined the measures of adequacy. On their basis, they assessed the adequacy of the mathematical model used. The analysis of the results of the conducted research showed that the developed mathematical model is sufficiently adequate. Therefore, both the mathematical model and the computer program based on it will be used in further work on supplying marine engines with mixtures of diesel oil and biocomponents.


2015 ◽  
Author(s):  
Jonathan DeHart ◽  
Robert Russell ◽  
John Storey ◽  
Michael Kass ◽  
Richard DeCorso ◽  
...  

The Navy pilot program investigated cost-effective technologies to reduce emissions from legacy marine engines. High-speed, high-population engine models in both commercial and Navy fleets were targeted. Emission reductions were sought that would minimize fuel penalty as well as installation and operating costs. Navy operating conditions and fuels limited options. Five highly rated technologies were laboratory tested on a Detroit Diesel Corporation 12V-71N engine using two military and three alternative fuels. Two control technologies were then shipboard tested (baseline, 1-year early degradation, and 9-year late-life). Conclusions and recommendations are provided to inform application of these and similar emission control technologies within both commercial and Navy fleets.


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