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ERASMUS MARINE ENGINEERING SYSTEMS (propulsion systems and engines). Subject’s goal. Familiarization with the propulsion systems that are mostly applied on board ships: engines, power transfer equipment, screws etc. and with the auxiliary systems and equipment. Basic explanations.
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ERASMUSMARINE ENGINEERING SYSTEMS(propulsion systems and engines)
Subject’s goal Familiarization with the propulsion systems that are mostly applied on board ships: engines, power transfer equipment, screws etc. and with the auxiliary systems and equipment.
Basic explanations • Main engine(s) – drive (propel) the ship • Shaft – usual mode of power transmission • Screw – common type of propulsion • Auxiliary engines – ‘production’ of electric energy • Auxiliary systems – necessary for operation of main engine, safety, comfort, cargo etc.
diesel engine propulsioned 95% of ships are propulsioned with slow speed d.e. steam turbine propulsioned gas turbine propulsioned electric motor propulsioned AC/DC AC/AC combination CODOG, CODAG, COGES, CODLAG... Propulsion systems
Engine room cross-section Is there a gearbox? Is there a clutch? Thrust bearing Shaft Screw ME
Typical arrangements one or two ME, several DG multi casing steam turbine AC/AC CODOG or CODAG
Propulsion power safety? TAKE ME HOME DEVICE
FPP vs. CPP ME should be reversed Pitch is changed How would the direction of movement be changed?
Propulsion System Coefficient of efficiency ve T=R+S vw v
Slip H, P [m] – pitch of the propeller n [min-1] number of the revolutions of the propeller v [m/s] speed
The ship’s speed measuring • Pitot’s tube (Pitotlog) • GPS • sonar...
Fuel characteristics residual fuel HFO, DO, BO viscosity (cinematic) density content of S(ulphur) or V(anadium) low flammability self combustion point CETANE number
Combustion oxygen needed theoretical amount of air there is always a surplus of air
Theoretical process p po Vo Vs V
piston mechanism parts: main bearings crankshaft connecting rods crossheads piston rods i pistons
combustion space piston cylinder liner cylinder head (exhaust, fuel, starting valves) camshaft mechanism combustion air system auxiliary systems (fuel, lubricating oil, compressed air, regulation system etc.)
Management - regulation ME VT Woodward regulator fuel pump handle regulator shaft drive In case engine’s having common rail fuel system there is a common fuel pump and the fuel valves (injection valves) are opened electronically and there has to be an electronic crankshaft positioning device.
Bridge control panel PREPARATION MANAGEMENT ALARMING PROTECTION
Reasons for starting failure? engine is not preheated fuel is not preheated engine is not turned slowly in order to lubricate it there is not enough scavenging air safety system activated not sufficient starting air pressure water hammer in the cylinder
Measures to reduce the emissions Primary – affects the combustion process Secondary – affects the exhaust gases (SCR)
Main engine preparation procedure preheating lube oil pumps starting starting air system preparation turning the engine slowly (on air or by a slowturning mechanism) with the indicating cocks opened indicating cocks closing setting the auxiliary blowers on ‘auto’ fuel oil system preparation cooling water system preparation main engine reversing steering gear, anchor etc.
Auxiliary (Main) Marine steam generators
Water to steam (vapor) 6 5 4 3 2 1 Q Q Q Q Q Q p=konst. Liquid Superheated vapor (gaseous phase) Evaporation process (Vapor)
T – s diagram T[K] Critical point p3 p2 p1 p4 K 6 saturation line superheated vapor 3 4 5 water 2 saturated vapor 1 s[kJ/kgK]
Steam process PREGRIJANA PARA MOKRA PARA VODA OSNOVNA SHEMA PARNOG PROCESA T-s DIJAGRAM PARNOG PROCESA
Sea water 25000 g/m3 NaCl + MgCl2, MgSO4, CaSO4... around 35000 g/m3
Natural (spring) water water dissolves CO2 and O2 dissolves CaCO3 and other minerals Ca(HCO3)2and Mg(HCO3)2 - alkaline CO2 - acidic
Distilled water produced in the ship’s fresh water generating equipment generates water with 4 mg/l or less vacuum evap. - 2 mg/l if more quality water is needed(1 mg/l )- ION EXCHANGERS are used
FOSTER WHEELER type • D, ESD I, ESD II, ESD III, ESD IV, ESRD • D- 40-55 t/h, 40-70 bar, Tpp=723-773 K • ESD=external superheater D
Dangers pipes overheating andbursting too high pressures – steam drum explosion furnace explosion fire in the furnace or fire of combustible residues on the pipes in the exhaust line safetyequipment
Burner management Purging!!! The simplest way: Through the steam pressure
Starting procedure combustion air ventilator starting fuel pump starting – fuel preparation furnace purging fuel/air mixture setting ignition working pressure
Exhaust gases boilers PRESSURES UP TO 20 bar FORCED WATER CIRCULATION – SMALL DIMENSIONS
Fuel and exhaust gas boilers connection • Cijevni snop s prisilnim strujanjem • SEKUNDARNI BUBANJ: POSUDA ZA SEPARACIJU I IZMJENJIVAČ TOPLINE • Zagrijač vode, pregrijač
Auxiliary (Main) Marine steam turbines
Propulsion turbines Several casings (high, medium and low pressure) Several stages – Parsons type turbine, although few stages at the entrance could be of DE Laval type Curtis type for reversed drive of the ship Gas turbine combinations
Propulsion turbines GEAR BOX THRUST BEARING
De Laval type Small power Pump and e. generators 10000-30000 min-1,e=0,3-0.4