boiler feed gas

[BZLAM21]

The natural gas feed pressure at 42 bar (g) and variable temperature according to climatic conditions , before the gas undergoes an expansion up to 7 bar (g) an electric preheater is installed upstream of the expansion to ensure a temperature of 40 ° C for feeding the boiler (MP)

I would like to know the influence of temperature and gas pressure on the efficiency of an MP boiler if the electric preheater fails.

 

[EdStainless]

As a first approximation what is the max power of the heater?
In some burner systems it throws off the F:A balance and efficiency.

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P.E. Metallurgy, consulting work welcomed

 

[LittleInch]

On a rough scale you're going to drop about 16C across your control valve.

Depending on your inlet temp and gas quality you might start to get liquid drop out.

No idea why they want 40C, but presumably making sure that they have no liquids in the burner system.

Only the boiler vendor can tell you, but I would have thought it was negligible so long as the gas didn't freeze anything or you get liquid in the system.

But if you go less than 0C all your piping and controls starts to freeze up and grow a large ice ball. Burner control valves don't like ice.

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

 

[MortenA]

@BZLAM21, you say "natural gas" but your pressure is rather high then. Are we really hearing about fuel gas at an [off shore] production facility where the gas is really MP gas with some condensables and maybe before the glycol drier?

In this case you are most likely going to see water and HC drop out if you dont heat the gas.

Best regards, Morten

--- Best regards, Morten Andersen

 

[MJCronin]

Please describe, in detail, the source and quality of your "natural gas" ...

MJCronin
Sr. Process Engineer

 

[BZLAM21]

HI EVERY ONE
this is the quality of natural gas
thanks.
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/raw/upload/v1639641709/tips/Doc1_yl26uc.docx[/url]

 

[LittleInch]

OK. This looks like "raw" gas off the top of a separator.

Your key number is dew point of 1C. You probably want to aim for a min of 5C or even 10C to avoid getting droplets in your gas supply to the burners.

Droplets could either block the burners or severely damage them.

So I would say if your gas supply is at least 10C there should be minimal impact, but any lower and its damage not efficiency that is the issue.

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