waste oil use as AF in cement kiln

Dear Ted

If I want to use waste oil as alternative fuel, feed point is precalcining firing. Should I analyse all of criteria of waste oil such as : C, H, N,...heavy metals, C.V, even PCBs or partly analyse ?? amount of waste oil is not high, just 30 litre/hours appoximately for 5500 tpd cement plant. 

Regards

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re waste oil use as AF in cement kiln

Hello Phanminh,

   For purely operational purposes you only need to analyse for Gross Calorific Value (G.C.V.) and Ultimate Analysis eg C, H, N, O etc. These two will allow you to calculate the Net Calorific Value or N.C.V.  (used for calculation of kiln specific heat consumption),  according to the following equations;-

kcal/kg: NCV = GCV - 50.6 * H - 5.85 * M - 0.191 * O
MJ/kg:    NCV = GCV - 0.212 * H - 0.0245 * M - 0.0008 * O
Btu/lb:   NCV = GCV - 91.2 * H - 10.5 * M - 0.34 * O

Where M is % Moisture, H is % Hydrogen (H from ultimate analysis minus the H in any moisture present), and O is % Oxygen (from ultimate analysis).

   Other analyses that may be required, depending on the source and variability of the waste oil are;-

- Ash content (if the waste oil contains significant amount of sludge)

- Chlorine (due to its strong influence on preheater buildups)

- Sulphur (due to its volatility and cyclic behaviour in the kiln)

- Viscosity (sometimes critical for pumpability of the oil )

- and possibly moisture content.

   My personal feeling is that you should analyse for all of the above, on at least a batch-by-batch basis.

  It may also be a requirement of your environmental licence(s) to analyse alternative fuels for the other things you have mentioned;-

- Heavy metals (particularly volatile metals such as mercury, lead, cadmium, and thallium etc Also chromium has become important due to concerns over Cr+6 effects on the skin.

- PBCs (due to their high toxicity)

- any other substances that may be specified by your local environmental protection agency.

   Your local environmental agency may also require that you do some stack testing, especially since you are using the waste oil in the precalciner rather than the main burner.

Hope this helps...

Regards,

Ted.

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re waste oil use as AF in cement kiln

Hello Ted

Thanks for your help. I think i going to analyses all of this for the first time.

Regards

phanminh

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