The Technology And Experimental Research On Exhaust Gas Pollutant Removal Of Marine Diesel Engine

At present,marine exhaust sulfur oxide emissions must not exceed the highest value in ECAS,as prescribed for Annex VI MARPOL73/78,which is equal to the flue gas sulfur oxide emissions after burning the fuel contained 0.1%sulfur.For reducing sulfur oxide emissions,the exhaust gas desulfurization technology,currently applicable to vessels and economical,is mainly wet scrubbing desulfurization technology.Compared all of the wet desulfurization technologies,this paper selects sodium alkaline exhaust gas scrubbing desulfurization technique as the research object.Then,the engineering prototype tests have been carried out on the type MAN5S50ME diesel engine.Based on the test,this paper expands the study of marine exhaust gas combined desulfurization and denitration technology.In the thesis,the following research works have been carried out:1)Based on double film theory,the model of Na OH solution absorb SO₂ was established.Combining with the mass transfer rate equation between gas and liquid phases and the chemical reaction equation,the absorption rate equations of SO₂ in the water and the NaOH solution were derived respectively.The measures of improving SO₂ absorption rate were summarized.2)On the basis of diesel engine emissions parameters,the scrubber of marine exhaust gas scrubbing desulfurization system was designed.According to the applicable condition of system,the types of scrubber and packing in the test were selected.3)In view of the test system,test scheme was designed.After experimenting in the light of test plan and analyzing the date,it is showed that the desulfurization efficiencies of the desulfurization system were above 99%.The exhaust gas after scrubbing meets IMO's criterion of sulfur oxide emissions.Oppositely,no CO₂ was absorbed by washing liquid.And a little of NOx was removed in exhaust gas by the desulfurization system.The nitrate content of treated waste water was conformed to IMO emissions guidelines about water discharge standards.The differential pressure between inlet and outlet of scrubber was low so that the system running resistance was small and there was little influence on diesel engine back pressure.Finally on the basis of sodium alkaline scrubbing desulfurization test and in combination with EGR venture washing technology,this paper designs the marine exhaust gas combined desulfurization and denitration system and puts forward the experiment scheme.This article research results on the exhaust gas washing desulfurization system provides favorable basis for application on the ship.And it is a reference significance to the late marine exhaust gas desulfurization denitration experiment.