Spray density

Most hydrocarbon facility process areas and high volume storage areas have standardized on a minimum supply or availability of four hours of firewater for the WCCE. The performance of risk analysis may reveal the level of fire water protection may be more or less than this requirement. Once a detailed design is completed on a facility or if a verification of existing water demands is needed, a simple tabular calculation of firewater requirements can be made. This table can be used to document spray density requirements, duration levels, code requirements and other features. Table 23 provides and example of arrangement to document such information. 

The design of fixed water spray fire protection over pumps should provide one or more spray nozzles positioned so that all parts of all objects within the protection pattern are thoroughly wetted and enveloped by the spray. The recommended water spray densities based on the horizontal coverage area is a minimum of 0.5 gpm/ft (20 Ipm/m ) (API 2030). 

The primary products are fed at the top of the extraction column. The composition of feed, extract, raffinate, and extractant is analysed in dependence on superficial velocity of the gaseous (continuous) phase. In two series of experiments either the phase ratio or the spraying density are kept constant. The stage construction is made by means of a computer program. 

The monoglyceride content of the raffinate is shown in Figure 10 as a function of the superficial gas velocity at a constant spraying density of 450 kg m 2h ... 

Fig. 10 Monoglyceride content of the raf finate as a function of superficial gas velocity at 12 MPa and 313 K for constant spray density of 450 kg m 2h" [8],...

The spray density should be tested by placing a sheet of paper beside the component. The paper should be uniformly darkened in a single pass. 

When the vapor rate is increased as much as possible, the region of higher spray density expands upward and an exponential increase in liquid tray-to-tray entrainment takes place. 

FIGURE 18.25 Variation of spraying density and heat-transfer coefficient along central axis of field of action of water jet on metal surface being cooled at water pressure before Sprayer of 1.5 MPa (after Urbanovich et al. [141]). 

The main spray production process is characterized by high frequency pulsing [4, 6, 10] whereby the spray density oscillates between lean and dense states with a period of about a millisecond, possibly due to timescales associated with bubble growth in recirculation regions in a vena contract that leads to periodic flushing of... 

The Pari eFlow nebulizer and AeroGen s nebulizers use this method of spray production. As with all nebulizers discussed so far, these devices can aerosolize several milliliters of formulation. However, spray densities are typically higher than with jet nebulizers, so that delivery times with vibrating plate nebulizers are typically lower than with jet nebulizers [29]. 

L = liquid spray density, gpm/fP of tower m, n, p = correlation coefficients... 

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