LPG Burner Setting

[oswald88]

Hi Everyone
I came across an issue in which heavy-ends/Oil sediments were found in gas train of an LPG fired burner, used in a drying oven of a Powder coating process. This results in frequent tripping of burner and affects product quality. System details as below

LPG Installation
Vaporizer - 40 Kg/h
with liquid trap
Primary regulator Rego 1588 VN - inlet pr. - 7 bar
Basket type filter - vanaz F0109
Secondary regulator Novacomet BP2303R, inlet pr. - 1.4 bar, Outlet pr. - 100 mbar

Burner - Baltur TBG 45P, 100 - 450 kw, 20 - 360 mbar
Gas Train - Dungs, MB-ZRDLE 407 B01 S20
Servo Control - Siemens SQN72.2A4A20BT

Since oil/heavy-ends is found only after secondary regulator, I feel it is because of incomplete combustion and condensation of LPG. Hence I reduced the LPG flow in gas train and increased the air flow.
Kindly throw some light in sorting this issue.

Oswald Vincent M.S Mech. Engg.

Keep Things Simple.

 

[chicopee]

So do you have a dual fuel burner?

 

[LittleInch]

Do you have a composition of your "LPG"

Sounds more like contaminated LPG to me.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[oswald88]

@Chicopee: No its only LPG burner

@LittleInch: P:30 B:70

Oswald Vincent M.S Mech. Engg.

Keep Things Simple.

 

[LittleInch]

My point is that"heavy ends and oil sediments" cannot come from pure LPG. Incomplete combustion of butane and propane delivers carbon and CO, not heavy ends.

Therefore these must be present in the fuel and then not vaporise when the lpg does. Check the fuel first.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[oswald88]

Thanks, I will work on it.

On the other hand, being a mechanical engineer, I want to read about each hydrocarbon (methane... pentane, hexane etc.) their properties, which will be a suggested book.

Oswald Vincent M.S Mech. Engg.

Keep Things Simple.

 

[chicopee]

In addition to the listed products of combustion from LI, it is conceivable that you could get soot from improper combustion.

 

[oswald88]

@Chicopee: Its not soot, instead its a sticky semi solid kind of stuff, black in colour and with a pungent smell.

Oswald Vincent M.S Mech. Engg.

Keep Things Simple.

 

[RossABQ]

Do you have drip legs ahead of each regulator?

 

[3DDave]

I can't think of any reason combustion would result in longer molecules.

Send a sample out for analysis to see what it is. The black is probably soot from incomplete combustion.

Also get a different supply of fuel, including a new tank.

I see some reports tracing contamination in small installs to incorrect hoses leaching pthalates.

 

[oswald88]

@rossABQ: We have one in the vaporizer outlet, not before each regulator
@3DDave: We have did that too, and the reports are clean. I am thinking to send the sediment for separate analysis, maybe FT-IR, distillation. If you have any idea, for specific parameters to look for during analysis, please suggest.

Oswald Vincent M.S Mech. Engg.

Keep Things Simple.

 

[chicopee]

"....sticky semi solid kind of stuff, black in colour and with a pungent smell..." that could possibly mean condensation from high humidity within the combustion chamber of the dryer oven mixed with soot develop the condition stated within the parentheses.

 

[oswald88]

Now another interesting issue, is a fork lift which runs in LPG fuel, got its vaporizer clogged. Photo of the damaged part attached.

Oswald Vincent M.S Mech. Engg.

Keep Things Simple.

 

[btrueblood]

Where and how did you take the fuel sample, and in what quantity?

My point is that the oil contaminant may be present in the fuel stream in fairly small amounts, and accumulate in low points over time. I would be looking upstream, e.g. in the basket strainer on primary regulator, in low points along the lpg line, and in the fuel tanks themselves, for contamination.

 

[btrueblood]

Oh. How new is this installation, or at least how new is the piping? Copper pipe? Did the piping get cleaned before installation?

 

[oswald88]

@btrueblood: I have also thought on this point. The sample was taken while unloading a road tanker from refinery. Probably, the heavy-ends do not get trapped because of flow velocity. Talking about strainer, I didn't find any contaminants while cleaning a strainer. The installation is one year old, and the pipeline is CS Sch. 40. Flushed with nitrogen last week and in two days the same issue is back.


Oswald Vincent M.S Mech. Engg.

Keep Things Simple.

 

[chicopee]

It could be some type of lubricant used by the pipe fitters during the initial installation.

 

[btrueblood]

Is it possible that the powder dust is accumulating in the burner pans? Though this doesn't explain your forklift - assuming you fuel the forklift from the same source at the burners, which you didn't explicitly state.

Could you put a strainer or similar trap in the low pressure line, upstream of the burner heads to see if you can trap/condense contaminants there before they reach the burners?