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Compressor fuel gas and/or start gas
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engr2GW
(Petroleum)
(OP)
2 Mar 21 10:40
When a compressor goes down or stops running, it seems the fuel gas or start gas continues to flow, does the compressor have an inbuilt system that stops taking the fuel gas or start gas? Some other engines have fuel injection systems that are run by the running of the engine (or part of it), but the fuel and start gas of a compressor is supplied (typically in the oil field) by an external source, usually gas from the facility the whose gas the compressor is compressing.
So apart from designing the fuel gas header to shut in when the compressor stops running:
1. Are there compressor system that ensures that no more gas intake happens when the unit is down?
2. If not, can continuous gas flow into the unit cause fire or other problems?
Thank you.
Hello,When a compressor goes down or stops running, it seems the fuel gas or start gas continues to flow, does the compressor have an inbuilt system that stops taking the fuel gas or start gas? Some other engines have fuel injection systems that are run by the running of the engine (or part of it), but the fuel and start gas of a compressor is supplied (typically in the oil field) by an external source, usually gas from the facility the whose gas the compressor is compressing.So apart from designing the fuel gas header to shut in when the compressor stops running:1. Are there compressor system that ensures that no more gas intake happens when the unit is down?2. If not, can continuous gas flow into the unit cause fire or other problems?Thank you.
As much as possible, do it right the first time...
1503-44
(Petroleum)
2 Mar 21 10:55
Compressor stations should also vent all gas to a safe location in the event of an ESD situation.
It is prudent to put an automatic shut in valve on the fuel gas system piping somewhere, either at the fuel gas takeoff from the main gas line, or outside the compressor unit area, or building housing compressors. It can also be helpful to have a manual, locked closed, bypass valve there to be used for black starts.Compressor stations should also vent all gas to a safe location in the event of an ESD situation.
engr2GW
(Petroleum)
(OP)
2 Mar 21 11:23
What (if any) are possible problems with continuous flow of fuel gas if the engine is not running?
Thank you 1503-44.What (if any) are possible problems with continuous flow of fuel gas if the engine is not running?
As much as possible, do it right the first time...
LittleInch
(Petroleum)
2 Mar 21 11:41
Or do you mean a gas engine / reciprocating engine?
Please explain the sentence "it seems the fuel gas or start gas continues to flow". This doesn't make sense.
But you really don't want gas going places it shouldn't. Just solve the problem if there is one.
Most gas turbines, which is what I think you're talking about, but you use the term "compressor" a bit loosely should have a shut off valve within their system. How else do you turn off the gas turbine??Or do you mean a gas engine / reciprocating engine?Please explain the sentence "it seems the fuel gas or start gas continues to flow". This doesn't make sense.But you really don't want gas going places it shouldn't. Just solve the problem if there is one.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
engr2GW
(Petroleum)
(OP)
2 Mar 21 11:48
Yes, you are right, I am referring to reciprocating compressors used in the oil field.
I agree that there should be independent shutoff system outside the compressor. I was asking if there is something similar in the compressor and if there is any serious danger if the unit is not running, does it just meet a dead end and stays until the next blowdown and startup or...
About my statement "it seems continuous to flow", that should have been a question mark, does it continue to flow or does it mean a dead end.
Thanks again.
Thank you for pointing that out LittleInch,Yes, you are right, I am referring to reciprocating compressors used in the oil field.I agree that there should be independent shutoff system outside the compressor. I was asking if there is something similar in the compressor and if there is any serious danger if the unit is not running, does it just meet a dead end and stays until the next blowdown and startup or...About my statement "it seems continuous to flow", that should have been a question mark, does it continue to flow or does it mean a dead end.Thanks again.
As much as possible, do it right the first time...
LittleInch
(Petroleum)
2 Mar 21 14:00
But assuming you now mean only the actual gas compressor, then it shouldn't make a big difference.
Most piston type compressors will in effect act like a non return valve, but the potential issue is that gas will leak backwards through the compressor due to leaky valves or leak out through seals in the machine.
Also if for some reason the pressure drop was negative then gas can flow through the compressor from inlet to outlet.
But if the outlet pressure remains higher than the inlet pressure then gas will not flow through the compressor when it is stopped in the "normal" direction.
Ah ok, that makes a difference, but I'm still not clear about your question I'm afraid as the OP seemed to talk about both compressor and engine in the same sentence.But assuming you now mean only the actual gas compressor, then it shouldn't make a big difference.Most piston type compressors will in effect act like a non return valve, but the potential issue is that gas will leak backwards through the compressor due to leaky valves or leak out through seals in the machine.Also if for some reason the pressure drop was negative then gas can flow through the compressor from inlet to outlet.But if the outlet pressure remains higher than the inlet pressure then gas will not flow through the compressor when it is stopped in the "normal" direction.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
engr2GW
(Petroleum)
(OP)
2 Mar 21 14:10
To answer your question about engine or compressor, I was not referring to the process, I was referring to "fuel gas" shut off, so yes, the engine.
I agree that the problem should be minimal in the compressor itself.
Thanks for the points LittleInchTo answer your question about engine or compressor, I was not referring to the process, I was referring to "fuel gas" shut off, so yes, the engine.I agree that the problem should be minimal in the compressor itself.
As much as possible, do it right the first time...
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News
theoldwizard1 said:Mine has a regular unloader and this ! Why, I don't know.
Click to expand...
It helps the pump to get up to speed faster with less load on the electric motor. So they can use the smallest electric motor that they can get away with.
The typical low-end compressor unloader only discharges the pressure between the pump and the check valve at the tank. When the compressor goes to start, that line immediately builds pressure as the unloader valve is closed whenever the compressor is running.
So this additional valve keeps the output line of the pump at a low pressure until the pump speeds up enough for the pressure and flow of air to shut off the valve.
On some of the wheelbarrow-style gas-powered compressors, they have a manual unloader valve that you open while starting the motor, for the same reason: easier starting. Heck, with my 18HP pressure washer, I have to do the same thing (hold the gun valve open while starting) in order to start it.
It helps the pump to get up to speed faster with less load on the electric motor. So they can use the smallest electric motor that they can get away with.The typical low-end compressor unloader only discharges the pressure between the pump and the check valve at the tank. When the compressor goes to start, that line immediately builds pressure as the unloader valve is closed whenever the compressor is running.So this additional valve keeps the output line of the pump at a low pressure until the pump speeds up enough for the pressure and flow of air to shut off the valve.On some of the wheelbarrow-style gas-powered compressors, they have a manual unloader valve that you open while starting the motor, for the same reason: easier starting. Heck, with my 18HP pressure washer, I have to do the same thing (hold the gun valve open while starting) in order to start it.