Steam Systems
The most efficient kind of turbine stage
What is a reaction (or Parsons) stage.
What is uniflow scavenging?
What ELFI systems allow control over.
Rate of injection as well as time and duration of injection.
Three differences between aeroderivative marine gas turbines and heavy duty gas turbines.
Modern (aeroderivative) gas turbines can be varied in RPM and are lighterweight but cannot run on heavy fuels.
Engine in which combustion occurs on both ends of the piston
What is a double acting engine?
The reason for sootblowers.
Soot buildup leads to inefficiency and increases the risk of burning through boiler tubes.
Reason for presence of piston rod and crosshead
Greater stroke to bore ration enables higher compression and thus more efficiency
Cycle used by low speed diesels when operating under low pressure gas fuel.
Otto cycle
Reason for which PWRs produce saturated steam.
Zircalloy tubes in which fuel is contained are limited by melting temp of 800F but is used due to low neutron absorption.
Reason for the propulsion system used in shuttle tankers.
Diesel-electric plants are used to enable dynamic positioning (DP) with FPSOs.
Purpose of desuperheater
What is controlling the temperature (and energy) of superheated steam
Reason for exhaust valve cages
Allows for maintenance, exhaust valves and seats are a common wear item and replacing a cage is far easier than lapping the seat on the entire cylinder head.
Two advantages of low pressure over high pressure gas injection systems.
Less expensive, lower NOx emissions.
Reason for multiple concentric shafting in gas turbines.
Allows increased compressor efficiency because different speeds may be used for different compressor stages.
Name of cycles used in gas turbines and steam turbine plants.
Brayton and Rankine cycles respectively.
How reversing is achieved in modern steam ships.
A reversing stage.
Purpose of a boost blower.
Allows two stroke engine to have necessary airflow to ensure scavenging of exhaust at low load and rpm operation.
Method by which dual injection mode lowers NOx emissions.
Rate of injection is decreased following initial combustion and then increased again once peak pressures and temperatures drop.
Three methods in which the cycle efficiency of gas turbines may be improved.
Regenerative cycle, intercooling and COGAS systems.
This is done in order to prevent cold end corrosion when using fuels high in sulfur.
Addition of a base to the cylinder oil.
An advantage of rotary regenerative air heaters over economizers beyond greater heat extraction.
Rotary regenerative air heaters allow for the use of reheating loops to improve efficiency between high and low pressure turbines.
Method in which NOx emissions may be controlled on traditional diesel engines.
Exhaust gas recirculation.
Why might bunkering for HP gas engines be easier than LP gas engine vessels?
Methane number is not a factor in HP, no risk of knocking.
Major advantage of PWR type reactors.
Water has a negative temperature coefficient which leads to a self stabilizing reaction. Additionally, if coolant were to be lost, the reaction would cease as water also serves as the moderator. When there is drop in steam demand:
1. Primary coolant temperature increases and density decreases
2. Moderating effect decreases
3. Reaction decreases
4. Primary coolant temperature decreases in accordance with drop in demand
5. Cycle repeats, the inverse is also possible where demand increases and the reaction increases to meet demand
First steam turbine powered vessel.
Parsons' Turbinia, launched in 1894