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Archive for the ‘Diesel engines’ Category

Check-out MAN Diesel & Turbo “Diesel Facts” publication

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I recently co-authored a draft version of a press release/article on reduced green house gas emissions (GNG) and low methane slip of the new ME-GI duel fuel engine. The ME-GI can be run on both conventional liquid fuel (diesel, heavy fuel oil etc) as well as natural gas. Check out the front page story in “Diesel Facts” 3rd issue 2011.
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November 2, 2011 at 1:51 pm

Presentation of paper no. 39 at CIMAC 2010 congress in Bergen available now!

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The presentation accompanying paper no. 39 is available

Written by aandreasen

October 5, 2010 at 8:05 am

Full text available for CIMAC paper no. 39 2010: Modelling of the oxidation of fuel sulfur in low speed two-stroke engines

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Full text version

Abstract

In large marine two stroke Diesel engines during combustion of sulfur containing fuel, the sulfur is oxidised to SO2 , mainly, although substantial amounts of SO3 and H2SO4 will form as well. These latter species may cause corrosional wear of the cylinder liner if not neutralised by lube oil additives. Potential attacks is due to either condensation of sulfuric acid on the cylinder liner lube oil film or direct dissolution of oxidised sulfur species in the lube oil film in which reaction with dissolved water may be the source of acidic species. In order to evaluate and predict corrosional wear of the liner material, it is pivotal to have realistic estimates of the distribution/concentration of oxidised sulfur species as well as a reliable model of
formation, transport and destruction of acidic species in the oil film. This paper addresses the former part by invoking a detailed reaction mechanism in order to simulate the oxidation of fuel bound sulfur and predicting the concentration of SO2 as well as the conversion fraction into SO3 and H2 SO4 . The reaction mechanism is coupled to a realistic model of the combustion process in which the air entrainment into the combustion zone is accounted for. The results of the simulation are evaluated with respect to previously applied models as well as existing data on the conversion fraction of SO2 to SO3 and H2 SO4 . The conversion fraction is found to be in a range of 2.6-6.7 %.

A pivotal part for the creation of the above paper has been the usage of the Cantera software for handling thermodynamics and integration of kinetic rate equations.

Written by aandreasen

June 22, 2010 at 10:13 am

Another paper accepted for the 2010 CIMAC Congress in Bergen

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I have authored a paper entitled “Modelling of the oxidation of fuel sulfur in low speed two-stroke Diesel engines ” in collaboration with my colleague Stefan Mayer from the Process Development Department, Marine Low-Speed, MAN Diesel in Copenhagen. The paper has just been accepted for publication for the 2010 CIMAC congress held in Bergen, Norway, and will be presented by myself at the congress on Wednesday 16th of June in the morning between 8.30 and 10.00 in Room C (according to the preliminary programme).

In the paper a detailed a detailed reaction mechanism is used in order to simulate the oxidation of fuel bound sulfur and predicting the concentration of SO2 as well as the conversion fraction into SO3 and H2SO4 . The reaction mechanism is coupled to a realistic model of the combustion process in which the air entrainment into the combustion zone is accounted for. The results of the simulation are evaluated with respect to previously applied models as well as existing data on the conversion fraction of SO2 to SO3 and H2SO4. The conversion fraction is found to be in a range of 2.6-6.7 %.

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April 29, 2010 at 11:34 am

Paper accepted for upcoming CIMAC congress in Bergen

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I have co-authored a paper entitled “TWO-STROKE ENGINE EMISSION REDUCTION
TECHNOLOGY: STATE-OF-THE-ART” in collaboration with my colleagues Michael Finch Pedersen and Stefan Mayer from the Process Development Department, Marine Low-Speed, MAN Diesel in Copenhagen. The paper has just been accepted for publication for the 2010 CIMAC congress held in Bergen, Norway, and will be presented by Michael Finch Pedersen at the congress on Tuesday 15th of June in the afternoon after 15.30 in Room B (according to the preliminary programme).

In the paper we present recent results on reducing the emission of pollutants from large two-stroke marine engines. We focus on primary methods, i.e. emission reductions obtained by in-cylinder methods in order to suppress emission formation. The methods presented are retrofit of fuel atomizers, water-in-fuel emulsion (WIF), exhaust gas recirculation (EGR) and a combination of WIF and EGR.

New publication out

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A new publication co-authored with my collegue Stefan Mayer at MAN Diesel A/S is out. The title is: “Use of Seawater Scrubbing for SO2 Removal from Marine Engine Exhaust Gas” and the paper is published in Energy & Fuels. As soon as possible a link to a full-paper download will be given.

Abstract:
The mechanism of SO2 absorption in seawater is treated. Emphasis is on applications of scrubbing of marine engine exhaust gas containing SO2. The formulated model is used to predict the influence of various parameters on SO2 absorption efficiency, e.g., seawater temperature, partial pressure of SO2, seawater salinity, and seawater alkalinity. It is found that the absorption capacity of standard seawater is approximately twice that of brackish water with close to zero salinity. The absorption capacity decreases with both decreasing salinity and alkalinity. Different scenarios in which the required water supply rate for a given SO2 cleaning efficiency is calculated. It is found that a 66% cleaning efficiency, corresponding to meeting the limits of SOx emission control areas (SECA) when operating on a fuel containing 4.5% w/w sulfur, requires a minimun water supply rate of 40–63 kg/(kW h) depending on the seawater composition in terms of salinity and alkalinity. Such data are essential in judging the operating cost of seawater scrubbing compared to alternative methods.

Written by aandreasen

October 26, 2007 at 3:47 pm