2 replies to this topic

[Tebzah]

Dear All

I have been assigned to evaluate "Slop Oil treatment" in one of the units within the plant,there is a boiler/fired heater wich operates on LNG. So what I'm asking for is ideas on how to calculate the heating values, efficincy and everything else involved in "Sizing".......pls help

Engineer in training

[Art Montemayor]

Tebzah:

You ask: “how is the heating value linked to this?” I guess you mean that you are firing a fuel in a boiler and you want to calculate the heating value.

You also state that your boiler “operates on LNG” – which is totally wrong. But I’ll assume that what you intended to say was that your fuel source is vaporized LNG. It makes a BIG difference. You can’t fire (burn) LNG. All you can burn is the vaporized product of LNG – which is essentially Methane.

You also want “ideas” on how to calculate “everything else involved in ‘Sizing’”- whatever that is.

I can’t help you with the “sizing” portion since I don’t know what you are talking about. You simply fail to state what it is that you want to size. If you want to calculate the amount of vaporized LNG you have to burn to generate a certain amount of steam or heating duty, you need to establish the lower heating value (LHV) of the fuel. To do that, you need a composition breakdown of the gaseous fuel. Once you have that, you use a spread sheet to assign the individual heating values to each of the constituents in the fuel according to their composition and simply add up the resultant contribution of each one. This is fully explained in any basic Chem Eng text book or stoichiometry course. For a lesson on how to set up and do the calculation, refer to the attached spreadsheet.

I don’t like doing student’s or young grad’s work for them. You don’t learn anything when I do the work for you. But this is the day before Thanksgiving and I feel I owe my Creator a lot to be grateful for. I hope you take this spreadsheet and do something with it – like learning how to set up your calculations and documenting them. It would also help if you worked on expressing your problem in a logical and organized manner so that we could all understand what it is specifically that you need help in.

I hope I have guessed correctly on what you needed.
 Gas_Composition_Calculations.xls   37KB   223 downloads

[Tebzah]

Thanx a lot Art__M**
your input is highly appreciated
this will definetely come in handy for me

Again thank you......