DUAL FUEL ENGINES PART 5 - DOUBLE WALL PIPE VENTILATION SYSTEM
Summary
TLDRThis video script offers an in-depth study of the double wall ventilation pipe system for fuel gas supply in dual fuel engines, particularly the MEGI engine. It explains the setup, including the gas valve train, double wall pipe structure, and the flow of fuel gas and fresh air. The script details the process from the deck to the engine room, the looping of gas to cylinders, and the role of ventilation fans and hydrocarbon sensors in maintaining safety and efficiency. The presenter encourages viewers to pause and take notes, emphasizing the importance of understanding the system for operational and safety purposes.
Takeaways
- đą The video discusses a double wall ventilation pipe system, specifically for fuel gas supply in dual fuel engines, using a MEGI engine as an example.
- đ ïž The double wall pipe system consists of an inner pipe for fuel gas and an outer pipe for fresh air circulation.
- đ The fuel gas enters the double wall pipe from the gas valve train located in the Cargo Machinery Room (CMR).
- đ The system includes a loop where the fuel gas is first introduced into the first cylinder and then circulated to other cylinders via U-pipes.
- ⎠The return pipe is used for startup and purging, but the gas does not return to the cargo tank after engine use; it vents out through a silencer.
- đš Fresh air for the system comes from the starting air system, reduced from 30 bar to 1.5 bar, and is activated by a valve when the engine starts.
- đŹïž Ventilation is maintained by two double wall pipe ventilation fans, which pull air through the system and vent it out with flame screens.
- đ The system includes hydrocarbon (HC) sensors to monitor for leaks in the inner pipe, with alarms set at 30% and a trip at 40% HC levels.
- đ§ The airflow and gas flow in the system are in opposite directions to ensure safety and proper ventilation.
- đ The video script serves as a base reference for understanding the setup and function of double wall pipes in dual fuel engine systems.
- đšâđ« The presenter encourages viewers to pause the video for diagrams, take snapshots, and engage with the content for better understanding.
Q & A
What is the primary focus of the video script?
-The primary focus of the video script is to explain the double wall ventilation pipe system, specifically for the fuel gas supply system in dual fuel engines, using a megi engine as an example.
What is the purpose of the double wall pipe system?
-The double wall pipe system is designed to safely transport fuel gas from the cargo machinery room to the engine room while also providing a continuous flow of fresh air on the outer side of the pipe.
What is the function of the gas valve train in the system?
-The gas valve train is where the fuel gas supply system connects, and it is the starting point from where the fuel gas enters the double wall pipe.
How does the fuel gas flow within the double wall pipe system?
-The fuel gas flows from the gas valve train into the inner pipe of the double wall system, passes through a small coffin, and then enters the engine room. It loops from the first cylinder to the other cylinders via U-pipes.
What is the purpose of the return pipe in the system?
-The return pipe is used during the start-up process to clear or blow off the lines and for ventilation purposes to purge the lines. It does not carry gas back to the cargo tank after the engine.
What is the role of the blue piping in the system?
-The blue piping represents the fresh air supply that goes into the outer pipe of the double wall pipe system, ensuring continuous ventilation.
Where does the fresh air for the double wall pipe system originate from?
-The fresh air comes from the starting air system, which is reduced from 30 bar to 1.5 bar by a reducing valve on deck.
How are the double wall pipe ventilation fans used in the system?
-The double wall pipe ventilation fans are used to continuously ventilate the system by sucking air from one side and venting it out into the atmosphere with a flame screen.
What is the significance of the hydrocarbon sensors in the system?
-The hydrocarbon sensors monitor the atmosphere around the double wall pipe system, helping to detect any leaks in the inner pipe. They trigger an alarm at 30% and a trip of the main engine at 40%.
What are the safety measures in place for the double wall pipe system?
-Safety measures include flame arresters on deck vents to prevent sparks from entering the system, and relief valves to handle pressure rises in the system.
Outlines
đą Double Wall Ventilation Pipe System for Dual Fuel Engines
This paragraph introduces the double wall ventilation pipe system used in dual fuel engines, specifically for a megi engine found on ships. It explains the basic setup of the system, including the gas valve train located in the cargo machinery room (CMR), where fuel gas enters the double wall pipe. The inner pipe carries fuel, and the outer pipe circulates fresh air. The fuel gas supply is distinguished by red piping, and the system includes a loop for distribution to multiple cylinders, with each cylinder head having a gas block. The return pipe is used for start-up and purging, not for returning gas to the cargo tank. The paragraph emphasizes the importance of understanding the flow and components of the system, and suggests viewers take a snapshot of the diagram for reference.
đŹïž Continuous Ventilation with Double Wall Pipe System
The second paragraph delves into the continuous ventilation aspect of the double wall pipe system. It discusses the necessity of fans to maintain ventilation, describing two double wall pipe ventilation fans that operate alternately. The fans take in air from the fuel entry side and expel it through vents with flame screens to prevent sparks. The paragraph also explains the role of hydrocarbon (HC) sensors in monitoring the system for leaks, with alarms set at 30% and a trip at 40% HC levels to ensure safety. The air supply comes from the main air compressors, reduced to 1.5 bar for the system, and is activated by a signal when the engine room start button is pressed. The summary concludes with an invitation for viewers to ask questions and engage with the content.
Mindmap
Keywords
đĄDouble Wall Ventilation Pipe System
đĄDual Fuel Engines
đĄFuel Gas Supply System
đĄGas Valve Train
đĄCoffer Dam
đĄU-Pipes
đĄHydrocarbon Sensors
đĄStarting Air System
đĄFlame Arresters
đĄVentilation Fans
đĄPurge Line
Highlights
Introduction to the double wall ventilation pipe system for fuel gas supply in dual fuel engines.
Explanation of the common setup in most ships with dual fuel engines.
Description of the gas valve train and its role in the fuel gas supply system.
Details on the double wall pipe's structure, with fuel inside and fresh air on the outside.
The process of fuel gas entering the double wall pipe from the cargo machinery room.
Diagram explanation for better understanding of the double wall pipe system.
Identification of red piping as fuel gas supply and its path to the engine room.
Description of the gas loop system and how it connects to the cylinders via U-pipes.
Clarification that gas does not return to the cargo tank after the engine room.
Explanation of the return pipe's function during engine start and line clearing.
Vent and purge line details, including their role in system safety.
Introduction to the blue piping as the fresh air supply in the double wall pipe.
The source of fresh air from the starting air system and its pressure reduction.
Mechanism of the automatic valve that controls air flow into the double wall pipe.
Importance of airflow direction in relation to gas flow for safety.
Role of double wall pipe ventilation fans in maintaining system ventilation.
Presence of hydrocarbon sensors for monitoring potential gas leaks in the system.
Safety protocols involving alarms and engine trips based on HC sensor readings.
Encouragement for questions and engagement with the content shared.
Transcripts
hi guys good morning so today we are
here to study about the double wall
ventilation pipe system uh the fuel gas
supply system for dual fuel engines the
one that I'm doing is a megi engine most
of the ships with dual fuel will be
pretty much the same setup a few
components here and there would be
slightly different but let's look at
this one so you can use this as your
base reference to learn and see what the
double wall ventilation pipe how it
looks and from where it starts what air
is in the double wall pipe how does it
reach the engine room and after going in
the pipes where does it go does it go to
the engine does it go to the atmosphere
got this diagram set up so please have a
look at this in fact I'd suggest that
you pause the video take a snapshot when
we refer or when I speak about the
things you guys should know what I'm
talking about once I explain this
diagram I'll take you down to the engine
room take you down to the deck let's do
this then the diagram looks good enough
so let's rock it the diagram basically
you need to understand first part that
side in this blackout line is in the CMR
the cargo Machinery room in that there's
something called the gas valve train I'm
sure you've seen the previous videos in
that fungal fuel gas supply system comes
to the gas valve train we are not
talking about the fuel the gas from
engine to now we'll be concentrating
basically on the double wall pipe what's
outside inside of a double wall inner
pipe is your fuel and on the outer side
is your air fresh air that will be
continuously circulated so the fuel gas
there comes out from that enters the
double wall pipe that starts here this
area is the deck then before going into
the engine room it goes into a small
coffin and then after that this whole
side is the engine room so basic
memorization let's do the red piping is
the gas the fuel gas fuel gas supplies
it there then we have a gas valve train
that after that comes out and the double
wall pipe starts outside the cargo
Machinery fuel gas coming out of there
ethane 380 45 degrees gas remember gas
coming in a double wall pipe cover Dam
into the engine room there's a loop and
it goes into the gas block of the first
cylinder and from the first cylinder it
is looped to the other cylinders by the
u-pipes these are not flexible pipes
these are fixed pipes all double wall
pipes each cylinder head has a gas block
like I've shown here so they are looped
into number of cylinders the gas enters
only into the first into the first
cylinder after that is just looped let's
look at the last cylinder this is
cylinder number seven as in my case so
you can see the yellow pipes are the
double wall pipes they are linked their
last loop the loop ends at the gas block
of unit number seven
and then the return pipe the return pipe
gas does not go back to the cargo tank
after the engine remember that gas does
not go back to the cargo tank after the
engine room the return pipe is only
during your start off that is when you
have to clear your lines you have to
blow off your lines or if the trip gas
trips for ventilation to just Purge the
lines okay so the purge line also
follows the same line uh through your
engine room through the coffin to the
deck and then it just goes off into a
silencer and then vents out into the
atmosphere
so that's your basic gas supply system
now we'll follow the blue pipe the blue
pipe the blue piping is your air the
fresh air that goes into the outer pipe
of this double wall pipe okay so it
comes from the starting air system the
main in the starting air system at 30
bar we get it from your main air bottles
main air compressors 30 bar is reduced
down to 1.5 bar by a reducing valve on
Deck this entire setup is on Deck but
the pipe comes from the engine room then
there is another valve automatic valve
this is uh this diaphragm is activated
only when the fuel gas system is we
press the start button in the engine
room these fans start and this valve
also gets the signal otherwise you'll be
just wasting uh compressed air into this
so This valve opens up we have air going
into the double wall pipe again this one
I will show you on deck so remember this
so this double wall pipe starts here
now again this pipe in case the pressure
Rises or it cannot cope up
this is a vent in the system and this
all the vents on Deck have wind screens
they're called as flame arresters so
that sparks don't go into the system all
of them have that
you can see them here marked here okay
so double wall now this is still single
pipe and now it enters the double wall
pipe on Deck before it goes into the
engine room
remember the gas flow and the airflow
the gas flow and the airflow are in
opposite directions Inner wall pipe goes
one way the gas in the outer pipe that
is air and the auto pipe goes the other
way so it goes the other way around
again into the Coffer Dam into the
engine into the first cylinder gas block
and then looped to the other cylinders
and coming in out
this way out into the Coffer Dam going
out here now this is what we need to
concentrate on
yes air is supplied by the system but we
need fans to keep the system
continuously ventilated so we have two
fans here they are called as double wall
pipe ventilation fans they are we can
use either one of them only one fan runs
at a time so this takes suction from
this side where the fuel enters this
take suction from this side so again
cross flow here it takes suction from
here delivers it and out again into a
vent into the atmosphere with a flame
screen this is usually above the the
cargo Machinery room or somewhere safe
location
in this pipe there are two HC sensors
hydrocarbon sensors in the pipe that I
can get the readings on my mop if you
remember the mop diagram in that we have
the HC readings there so it's pretty
simple to flow again from starting a
system going into reducing valves the
main inlet valve this is the wind system
start off the double wall pipe starts
here goes all the way cofferdam engine
room Loops into the cylinders gas blocks
Outlet back again Coffer Dam
right up here double all pipe went fence
and uh vented out remember the relief
all has to be there in system in case
the pressure Rises for some reason or
the other this has to be there and
another thing
there are two HC sensors just located in
the engine room near the gas wall pipes
in the forward side I'll show you this
one down and the outside of the engine
so I hope this was quite clear for you
guys the flow system the flow sequence
of the double wall pipe the air and
double wall pipe remember the air and
the double roll pipe is not any special
air it's just your air from your main
air compressors going through entire
system you know and then finally it's
the fans that uh pull out that suck out
the air and vended out of the atmosphere
but before vending it out continuously
there are hydrocarbon sensors two two HC
sensors that monitor the monitor the
atmosphere off the double wall pipe this
helps the pipe this helps us know that
if there are any leaks in the inner pipe
so very important at 30 we have an alarm
and at forty percent uh HC we have a
trip the main engine so it's a Sunday
and I hope I made your Sunday I did I
did make my Sunday I like to share
knowledge and by sharing knowledge we
end up gaining knowledge as well so do
shoot your questions in the comments
below do like do share do subscribe all
right take care cheers the deep sea man
out
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