Operation of Exhaust Gas Economizer
The EGE is started in operation (generating steam) when the main engine (diesel engine) is started to use. Preparation is required before the main engine is to be used for sea passage and when the engine will be stand still.
a. Start-up Operation
When the EGE is in cold condition, supply feed water to the EGE water side from the auxiliary boiler by the following:
a.) Open the following valves:
i. air vent valve and pressure gauge root valve of the EGE
ii. suction valve of the boiler circulating pump
iii. inlet and outlet valve of the auxiliary boiler drum to EGE
iv. inlet and outlet valve of the EGE
b.) Make sure that the drain valve of the EGE is closed. Start the boiler circulating pump and gradually open the delivery valve until full open. Wait until water spouts at the EGE air vent then close the air vent valve.
c.) If the steam drum separator is not under pressure, open the air vent valve (atmospheric valve) and operate the main engine. Close the air vent valve of the separator drum when steam pressure exceeded to more than 0.1 MPa.
d.) When the main engine is already running and steam generation is increases, open the steam outlet valve of the steam separator gradually to avoid water hammer in the piping system.
Stopping
EGE operation stops when the main engine ceases its operation and no exhaust gases passes to the tubes. In normal cases, the boiler circulating pump need not to be stopped the operation. In such case that the boiler circulating pump should be stop, such as carrying out maintenance and in unavoidable circumstances carry out the following;
i. Operate the boiler circulating pump at least 30 minutes or more after the main engine is totally stopped. It should continue to run until the EGE tubes temperature is less than 150oC or equal to the steam temperature at the separator drum.
ii. Stopped the boiler circulating pump when there is no abnormal condition in the exhaust gas side of the EGE, such as soot fire, temperature abnormalities, etc.,
iii. When the boiler circulating pump is stopped, close all the valves and open the air vent valve of the EGE water side.
