no. 6 fuel oil 1

[gie]

hi! I was told by my boss to determine the volume of water will be converted into steam in one liter of bunker oil in the boilers of our plant? pls help me, i have a hard time analyzing the problem given to me. thank you!

 

[TD2K]

How do you think you would start to determine this?

 

[22082002]

can you tell some thing more about bunker oil, is it fuel?

 

[rbcoulter]

Maybe the company that built the boiler can tell you.

 

[25362]

22082002: Bunker C fuel oil, aka Navy Heavy; No.6 fuel oil, is a heavy residual petroleum oil used as fuel by industry, power-production and large-scale heating installations, and by ships. "Bunkering" is storage of fuels (solid or liquid) in a container from which they can be continuously or intermittently withdrawn for use.

gie: use the calorific value of the fuel, a certain % efficiency in the transfer of this heat to the water, and the sensible and latent heats of water at the operating pressure. Better start using "mass" units; at the end you may convert back to the "volumes" requested by your boss, by the use of densities.

If you feel you're unable to carry out the estimates, ask the boiler maker to do them for you.

 

[gie]

thanks to all who replied in my problem. More power to all of you!

 

[jmw]

Visit

http://www.steamesteem.com

You may find some useful calculators there.

 

[gie]

ur replies are a big help! thanks to all of you. Does anyone has API data book. i wanna know the molecular weight of no. 6 fuel oil. the viscosity, cst @ 50 degrees celsius is 230 and gravity API @ 15.6 degrees celsius is 17.4. there are correlations in the API data book for gravity and viscosity versus molecular weight. thank you...

 

[jmw]

By the way, do you have a boiler make up water flow meter and a fuel flow meter?
Checking your fuel consumption records and the make up water usage should give you a good idea of how much water is being converted into steam.

 

[25362]

Given the MW you can estimate the approximate formula C_xH_y of the net hydrocarbon structural composition by knowing the %w/w of carbon and of hydrogen. As an example, for a MW of 550, C = 85%; H = 13%.

x = 550/{12[1+(13/85)]} = 39.75; y = 550 (13/85)/(1+13/85) = 72.96

The formula being then: C_39.75H_72.96 or C_nH_2n-6.5 .

 

[jmw]

Molecular weight can be determined (estimated)from ASTM D 2502 - 92 for which you require the viscosity at 100degF and 210degF.

 

[25362]

There is also a well known general graph for hydrocarbons by Fluor Daniel Inc. correlating molecular weight, characterization factor, ^oAPI gravity, and boiling point, ^oF, without the use of viscosities.

To jmw: is the test #2502 intended for fuels or for lube fractions ?

 

[chicopee]

Hereis a somewhat simple and ballpark estimation:
1) Know btu or calorie content of #6 oil per either lbm, gallons ,liter, or kg depending on the references such as kent"power",Perry Chemical Eng or Mark Eng. hndbks."
2) know efficiency of steam generator (=efficiency of burner X efficiency of heat transfer area)
3) Calculate the available heat (=Btu/lbm content X efficiency of steam generator)to evaporate the water.
4) Convert answer in 3) to either Btu's/gal, Btu/gal, Calories/kg or Calories/liter of fuel. Selection of the units is based on your preference as long as steps below have consistent units.
5)Determine amount of Btu or Calories to evaporate 1 lbm or 1 kg of water- use either Mollier diagram or water/steam table. Of course you will need to know initial and final states (temperatures & pressures) of water and steam, respectively within that steam generator.
At atmospheric pressure and 212 degrees F it will take 970 Btu's of heat to evaporate 1 Lbm of water from liquid saturation to vapor saturation lines.
6)Since we are assumuing a closed system, divide step #4) by step #5) and you should have an answer in either Lbm or Kg.
7)Go back to steam table or Mollier diagram and pick a value for specific volume (will have to convert units watch out)at initial state and mulitply it by answer in #6) to either get volume of water evaporated.

8)Again watch out for the units in any of the above steps Depending on your references units may become a mix bag between degrees F,K,C,R; psia,psig,& bars; cuft/lbm and liter/kg; btu/lbm & cal/kg; cu.ft,gallon & liters.

 

[jmw]

If i may quote you: "...I was told by my boss to determine the volume of water will be converted into steam ...."
Can i ask if "determine" is the exact word he used? and if he explained why he wanted this information?
You have two approaches to the answer and you may require one or both. The first is the theortcial calculation which requires, as has been indicated by other contributors, some estimation of efficiency i.e. the theoretical efficiency. I hinted in one of my replies that you could "determine" the answer simply by looking at how much fuel you historically use to raise an amount of steam represented by the amount of make-up water consumed. Thus you may also have to take a look at your fuel records to see how much your fuel quality varies. Fuel quality, especially the heavier grades, is notoriously variable, contamination is a natural hazard in fuel supply and storage, both incidental and deliberate (corruption can be a serious problem... at one site i attended during a power station commissioning the fuel was found to be so well adulterated with water the engineers said you could shower in it! At another site i was told they used commercial grades of fuel for boiler operations. Then they produced their records... as a petrochemical plant they were not averse to burning their mistakes as fuel!) so how do you account for the effects of fuel variability? This may require you to break down the historical data and correlate it with performance. Do you have any established performance indicators? Do you have fuel analysis records? Do you have independent testing of fuels?
Your theoretical calculation may not tell you the whole story nor answer your bosses real needs.
In most burner operations efficiency depends on creating an effectiove spray pattern via the burner nozzles such that the fuel is fully combusted in the most appropriate region of the boiler. If the fuel viscosity at injection is too low a soft non pentrating spray may be created which not only doesn't mix properly with the air, it burns in the wrong place. If the viscosity is too high then large droplets are created which don't burn quickly enough and the result is burning fuel collecting on the boiler tubes with increased soot production (and soot blowing) and the higher risk of tube burn out. In the fuel supply to large diesel engines (because the fuel is usually less viscous and is filtered and centrifuged before the engines), the viscosity is controlled by a viscometer which measures the viscosity and adjusts the fuel heaters accordingly to maintain optimum viscosity. In burner operations viscometers have been quite unable to manage the fuel quality so it is more usual to control the fuel heaters using tfuel temperature as the controlling parameter. This is very inexact. It requires a number of compensating actions. These include a combination of daily fuel analysis and re-calculation of the optimum fuel temperature to assure the fuel viscosity is correct, increased air flow to provide excess oxygen to help complete the combustion process and visual flame inspection. Just running on 4.55 excess oxygen can cost a typicl p[etrochemical palnt around £100,000 a year. Tube failures can cost £50,000 per event (plus incidental losses such as lost production) and some unforyunates also suffer heavy fines for pollution. All of which says that efficiency in real operations can be far removed from theoretical. But you should have good historical data, fuel receipts, make up water consumption, suppliers qufuel quality data, in house test data and so on. At the end of the year the accountants want to know operational costs. This generally means how much did we spend and what did we get. How much fuel did we burn and how much steam did we actually raise and so on.
Hence i ask, why does your boss want to know and what does he want to know? Is this an intelectual excercise or a practical one?
PS visit the

http://www.solartronmobrey.com

web site and look for press releases, there you will find an article about Huntsman chemicals in the Uk talking about the change to viscosity measurement from temperature measurement.

 

[jmw]

25362...
I'll look up the 2502 standard when i am in the office tommorow and get back to you.... i'd be interested in your Fluor Daniels chart and discoverimng what a charecturisation factor is based on.
Incidentally, 2502 is a set of look up tables and charts, i am very interested in anyone who knows of a good calculation method based on viscosity or density, since we measure both density (and hence API degrees) and kinematic viscosity on line i need a computational method to provide on-line molecular weight. Can anyone help out?

 

[25362]

jmw: I don't have a scanner to send it to you but you can find the graph, for example, in appendix 1 of Elements of Petroleum Processing by D.S.J. Jones published by John Wiley and Sons, Inc.

 

[25362]

The API Technical Data Book gives a graph correlating the MW with MeABP and ^oAPI gravity for relatively narrow boiling fractions.

 

[jmw]

25362, the application of ASTM D 2502-92 is declared to be: "..applicable to samples with molecular weights in the range 250 to 700 and is intended for use with average petroleum fractions. It should not be applied indiscriminately to oils that represent extremes of composition or possess an exceptionally narrow molecular weight (relative molecular mass) range."
I would take a guess that synthetic lubes would fall outside this standard but i would not know if other lubes fall within it.
Thanks for your references.