I don't know why anyone would use diesel oil in a boiler. Todays cost of MGO in Rotterdam is $1027 a tonne, down from $1065 on the 11th. IFO 380 is $641 today, down from $660 on the 11th.
However, may I refer you to Reeds Steam Engineering Knowledge, Vol 9, page 54, which says, in part,
"Fig 1.31 shows the business end of the relatively recent Y-jet steam atomising oil burner that is finding increased favour for water tube boilers for the following reasons:
1. Deposits are greatly reduced, hence soot blowing and water washing of the gas surfaces need not be carried out as frequently as before. (18 months or more between cleaning has been found possible)
2. Atomisation and combustion are greatly improved.
3. % CO2 is increased (% O2 reading has been lowered to 1% or below) hence boiler efficiency is greatly improved.
(My note, great for Inert Gas systems on tankers)
4. Atomisation is excellent over a wide range of loads and the turn-down ratio is as high as 20:1 and above.
5. With improved combustion and turndown ratio, refractory problems are reduced."
The differences between IFO and MGO as a boiler fuel, apart from price, are sulphur content and viscosity. Sulphur in MGO is generally less than 0.05%. The cost of 1% Sulphur IFO380 is currently $703 in Rotterdam, slightly more that the cheaper stuff at $641. 1% sulphur fuel will be mandated by MARPOL Annex VI by (I think, without looking it up) 2015. Steam atomising reduces the need to lower viscosity to 11 CTS, so you don't need to use nearly as much steam to heat the stuff, it can be blasted in at (eg) 180CTS, as long as it can be persuaded to flow. (you need to heat IFO 380 to around 135C to get 11 CTS, but it will flow well enough at 50 C)
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