Oil tanks

Rolling oil tanks were corroded on surfaces contacting the emulsion. Small pitlike depressions were present beneath aluminum soap deposits. Each pit was surrounded by a lightly etched region exactly mirroring deposit patterns (Fig. 6.26). 

The horizontal surfaces should be coated because there is residual water in the ballast and there are water-oil mixtures in the crude oil tanks when ships travel empty and these can cause severe corrosion attack. In the lower part of the tank, up to about 1.5 m from the base, a combination of coating and cathodic protection with special anodes is chosen. Basically the anodes could take over the exclusive protection in this area, but with empty ballast tanks containing residual water or empty crude oil tanks with aggressive oil-water mixtures containing sulfur compounds, they do not prevent corrosion. 

Surface treatment Ballast tanks (mA m ) Crude oil tanks (mA m )... 

Cathodic protection by means of impressed current is very adaptable and economic because of the long durability of anodes and the large number of anode materials and shapes. Some examples are described here. Internal cathodic protection of fuel oil tanks has already been dealt with in Section 11.7. The internal protection of water tanks is described in detail in Chapter 20. 

Lube oil units are typieally available in two versions the manu-faeturer s standard or in aeeordanee with API Standard 614. The major eomponents of a unit are the oil tank, auxiliary oil pump, double filter and, seleetively, one or two oil eoolers. All eomponents of the smaller units are mounted on a eommon bedplate, separated from the other eomponents. The oil ean be heated by an eleetrieal or steam-powered heating unit. The neeessary instrumentation is a standard supply item and, if requested, the switehes and motors ean be prewired. The main and auxiliary oil pumps are driven by different types of drivers (e.g., one by an eleetrie motor and the other by either a small steam turbine or by direet eonneetion to the shaft end of a major maehine easing in the turbotrain). 

For liquid film seals, an overhead tank is normally used. The tank functions as part of the differential pressure control. The process gas is referenced to the top of the tank, and the tank s physical height becomes a manometric leg. The oil level is controlled in the tank. Figure 8-11 shows an alternate arrangement for the overhead seal tank, including the recommended operating levels and volumes. The material of the seal oil tank should be stainless, the same as that recommended for the accumulator. 

Ninety minutes after the fire started, the sphere burst. Ten out of 12 firemen within 50 m were killed. Men 140 m away were badly burned by a wave of propane that came over the eompound wall. Altogether, 15-18 men were killed (reports differ), and about 80 were injured. The area was abandoned. Flying debris broke tbe legs of an adjacent sphere, w hich fell over. Its relief valve discharged liquid, which added to the fire, and 45 minutes later this sphere burst. Altogether, five spheres and two other pressure vessels burst, and three were damaged. The fire spread to gasoline and fuel oil tanks. 

Another incident occuned when contractors were employed to clean several black oil tanks, 4,500-m capacity, so they could be used for the storage of kerosene. The details of the contract were agreed verbally. After removing solid residues and the heater coils, the tanks would be sprayed w ith hot water and a detergent. Floodlights were suspended through roof manholes and were to be removed before the tanks were sprayed. 

Routine operations of many ships have resulted in oil pollution. Cleaning up minor spills on deck and in the engine room is now treated very carefully. Fuel-oil and crude-oil tanks are cleaned from time to time. In the past the polluted oil-water mixture was dumped overboard, but now it must be pumped ashore for treatment. 

Figure 15.29 The layout of a typical diesel generator engine room. 1 Diesel generator set 2 jacket water header tank 3 lubricating oil service tank 4 air receiver 5 diesel-driven compressor 6 batteries and charger 7 engine control panel 8 pneumatic control panel 9 fuel oil control panel 10 engine exhaust silencer 11 charge air filter 12 daily service fuel oil tank 13 three-section radiator...

An alternative method of assessing the hazards of a specific work task may be as follows. The work task envisaged, to be carried out by a contractor, is that of connecting an additional outlet to fuel oil tanks situated within an oil tank room, which is located below ground level. 

Underground and underwater Underground fuel/oil tanks and pipelines water, fire protection, gas and compressed underground air distribution schemes underground metallic sewers and culverts underground communication and power cables deep wells other buried tanks and tanks in... 

The zinc silicate, epoxy and coal tar/epoxy coatings are still used. Coal tar epoxies are used for crude oil tanks, sometimes on all the interior surfaces but more often for a) the bottom of the tank and about 2 m up the sides, b) the top of the tank and about 2 m down the sides, and (c) other horizontal surfaces where seawater ballast may lie. These partly coated tanks are frequently also fitted with cathodic protection to prevent corrosion of the uncoated areas when seawater ballast is carried. The pure epoxy or coal tar epoxy coatings applied in bulk cargo tanks used for the carriage of grain must be approved by the North of England Industrial Health Service, or by similar independent authorities in other countries. 

Fig, 7-3. Sketch showing details of cathode-ray tube immersed in transformer oil tank. P is an aluminum plate with the sample on the under side. is a lead box with a slit that allows the x-rays, generated in a sample, to escape to the spectrometer. (Courtesy of Jesse, Rev. Sci. Instr., 6, 48.)... 

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