Liquid fuels open tanks

The foam concentrate used with subsurface systems should be a fluoroprotein type for best results, although some AFFF foams are listed for substitutable application (because of their "fuel shedding" properties). The minimum foam solution rate should be 0.3 gpm/ft (12 Ipm/m ). The supply of foam liquid should be adequate to operate the system for 20 minutes. The foam injection point must be above the level of any residual water in the bottom of the tank. Subsurface foam application is not recommended for open or covered floating roof tanks or cone roof tanks with internal floating covers. 

After a moment, when a proper vacuum condition is obtained, the valves on the dispenser and the fuel tank will open and liquid hydrogen flow will be initiated. 

Cmde propane is also known as LP (liquid petroleum) gas. It is generally used in mral areas that are not served by gas pipelines. LP contains about 80% propane. It can be stored as a liquid under normal temperatures, provided it is stored under pressure. The liquid propane occupies a much smaller volume than the gaseous propane. When pressurized tanks containing LP are opened, the gaseous fuel is released. 

Liquid butane (C4H10) is stored in cylinders to be used as a fuel. The normal boiling point of butane is listed as —0.5 °C. (a) Suppose the tank is standing in the Sim and reaches a temperature of 35 °C. Would you expect the pressure in the tank to be greater or less than atmospheric pressure How does the pressure within the tank depend on how much liquid butane is in it (b) Suppose the valve to the tank is opened and a few liters of butane are allowed to escape rapidly. What do you expect would happen to the temperature of the remaining liquid butane in the tank Explain, (c) How much heat must be added to vaporize 250 g of butane if its heat of vaporization is 21.3 kj/mol What volume does this much butane occupy at 755 torr and 35 °C ... 

Capacitance probes (Fig. 18.18(a)) are widely used in liquid level measurements. It is possible, when the tank waUs are metal, to use a single bare or insulated metal rod as one capacitor plate and the tank walls as the other. More frequently, capacitance probes consist of a metal rod within a concentric cylinder open at the ends, which makes the transducer independent of the tank construction. An interesting appHcation of this type of capacitance probe is in aircraft fuel quantity indicators. Capacitance switches can be utilized as depicted in Fig. 18.18(b) to provide noncontact point measurements of Hquid level. 

There are currently no standards for use of gas detectors for fuel storage installations and no fuel storage installations within the UK where gas detectors are installed. Gas detectors are available but the dispersion of gasoline vapour is complicated and hence effective detection by gas detectors is subject to many uncertainties. Open path detection devices are available and could provide boundary detection at bund walls or around tanks. Liquid hydrocarbon detectors, however, may offer effective detection because it is easier to predict where escaping liquid will collect and travel. There are a number of installations where liquid hydrocarbon detectors are installed. Typical locations would be in a bund drain, gutter or sump where sensors can detect oil on water using conductivity measurement. The detection system may be subject to failures or spurious trips... 

If the liquid (gasoline is an example) has a high vapor pressure. This will make the vapor space in the tank car fuel rich. However, the vapor around the open hatch may be in the flammable range. 

For the main fuel drain circuit, bellows-sealed, mechanically operated, poppet alves (.see Section 15-3) will be placed in scries with the freeze valves to establish a stagnant licjuid suitable for freezing. Normally these mechanical valves will be left open. By melting the plug in the freeze line and opening gas-equalization valves, the liquid in the reactor will flow by gravity to the drain tank, and the gas in the drain tank will be transferred to the reactor system. Thus gas will not have to be added to, or vented from, the primary system. 

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