Oil fired boiler

Fuel Characteristics Fuel choice has a major impact on boiler design and sizing. Because of the heat transfer resistance offered by ash deposits in the furnace chamber in a coal-fired boiler, the mean absorbed heat flux is lower than in gas- or oil-fired boilers, so a greater surface area must be provided. Figure 27-42 shows a size comparison between a coal-fired and an oil-fired boiler for the same duty. 

FIG. 27-42 Comp arison of the sizes and shapes of typical 500-MWg coal- and oil-fired boilers. Adapted with permission fixjm Lawn, Principles of Combustion Engineering for Boilers, Academic Press, London, 1987.)... 

There are a number or types of special brick obtainable from individual producers. High-burned kaolin refractories are particularly valuable under conditions of severe temperature and heavy load or severe spalling conditions, as in the case of high-temperature oil-fired boiler settings or piers under enamehng furnaces. Another brick for the same uses is a high-fired brick of Missouri aluminous clay. 

High-temperature corrosion is induced by accelerated reaction rates inherent in any temperature reaction. One phenomenon that occurs frequently in heavy oil-firing boilers is layers of different types of corrosion on one metal surface. 

Harada, Y. High Temperature Corrosion in Heavy Oil Firing Boilers, Proc. Fifth Int. Cong, on Metallic Corrosion (Houston, TX National Association of Corrosion Engineers, 1974). 

The ash deposits resulting from the combustion of solid and oil fuels often contain appreciable quantities of other corrodants in addition to vanadium pentoxide. One of the more important of these is sodium sulphate, and the effects of this constituent in producing sulphur attack have been mentioned. The contents of sodium sulphate and vanadium pentoxide present in fuel oil ash can vary markedly and the relative merits of different materials depend to a great extent upon the proportions of these constituents. Exposure of heat-resisting alloys of varying nickel, chromium and iron contents to ash deposition in the super-heater zones of oil-fired boilers indicated a behaviour pattern depending on the composition of the alloy and of the ash... 

The efficiency of electric boilers is high, often 95 to 98%, with perhaps a 5 to 10% efficiency decrease from high fire to low fire (compared with an oil-fired boiler, which may only ever reach 82% efficiency and may have a 10 to 15% spread). 

In modem, packaged horizontal FT boilers, the furnace is the most important heat-transfer component, typically providing 50 to 60% of the total heat transfer from only 30% or so of the total available heating surfaces. This level of heat transfer, coupled with the additional heat extraction obtained by the various multiple-pass designs (four passes is a practical maximum) provide efficiencies of 80 to 83% GCV. As a result, there generally is little additional benefit to be obtained from the use of economizers or air heaters, especially when using oil-fired boilers, which can operate at up to a 3% or so higher efficiency level compared to gas-fired units. 

ORGANIC ANALYSIS OF OIL-FIRED BOILER EFFLUENT. BY PERCENT WT, IN EACH OF THE LEVEL I FRACTIONS. 

Cost of steam generators. Price is for packaged unit with steel tubes, gas-fired. Multiply by 1.02 for oil-fired boiler. Multiply horsepower by 33,500 for number of Btu s. 

On the Black Sea the main Romanian town is Constanta, which is an important port having the energy demand provided by the TPP Palas, the town utility with an output of 220 MW electricity provided by four fuel oil fired boilers. 

Eight of the Bahco scrubbers are located on oil-fired boilers in pulp mills. The boilers range in size from 50,000 to 375,000 Ibs/hr of steam and produce 10,000-145,000 ACFM of oflF-gas at about 340°-360°F. Each of these units operates with caustic soda as the scrubbing reagent. The units operate at a controlled pH of 6.5 which maximizes the production of sodium bisulfite and limits unwanted sulfate oxidation. The soluble bisulfite product is utilized in the pulping operation. Particulate and mist concentrations are held to about 0.02 grain/SCFW and SO levels are reduced by 97-99% from about 1500 to about 30 ppm. These units have operated continuously without any operational upsets. 

Removal of SO2 from actual boiler fiue gas was first tested in a 1500 ft /hr, 6-inch diameter unit operating on a slipstream from a 50 MW oil-fired boiler. This equipment was operated satisfactorily around-the-clock for periods as long as one week. Scaled up 18-inch diameter adsorbers, capable of handling gas rates of 20,000 ft /hr, also have been operated satisfactorily on fiue gas from an oil-fired boiler and on simulated Claus tail gas. Data from these continuous units showed SO2-removal capabilities to as low as 50 ppm. 

Given Andersen 2000 sampler data from an oil-fired boiler, you have been requested to plot a cumulative distribution ciuve on log-probability paper and determine the mean particle diameter and geometric standard deviation of the fly ash. Pertinent data are provided below. 

As other speakers at this symposium have described, the use of fuel gas produced by biomass or solid waste gasifiers can reduce the use of petroleum fuels in stationary combustion equipment (oil-fired boilers, diesel engines for electric generators or irrigation pumps). Stationary engines and furnaces, however, are not the only big users of petroleum fuels in lesser developed countries (or LDCs, the term we will employ to describe the 88 poorest nations in the world). As is the case for industrialized nations, lesser developed countries need liquid transportation fuels, and probably will for a long time. Brookhaven reports that most LDCs have increased their dependence on highway transport over the last two decades (lb). 

Nelson, H.W., et al, A Review of Available Information on Corrosion and Deposits in Coal and Oil Fired Boilers and Gas Turbines", ASME, 1954. 

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