Pressure drop backward

Lapple s method is useful when the upstream pressure of a header is known and the downstream pressure has to be calculated. However, it is often required to develop the pressure profile of the flare headers as a function of the distance from the stack. For this reason, it is more convenient to calculate the pressure drop backward, starting from the flare stack exit where the pressure is atmospheric. Figure 20 provides another plot which enables the pressure loss calculation when the downstream pressure is known. 

The reaction turbine, shown schematically in Figure 2-2, is generally more efficient. In its primary (stationary) nozzles only half the pressure energy of the gas stream is converted to velocity. The rotor with a blade speed matching the full-jetted stream velocity receives this jetted gas stream. In the rotor blades the other half of the pressure energy is used to jet the gas backward out of the rotor and, hence, to exhaust. Because half the pressure drop is taken across the rotor, a seat must be created around the periphery of the rotor to contain this pressure. Also, the pressure difference across the rotor acts on the full rotor area and creates a large thrust load on the shaft. 

The next component to check is the injector. Usually, only three things happen leaks and plugs, which are immediately obvious, loop contamination, and carry over. Plugging can be localized by working backwards from the column connection port through the loop connections, with the injector first in the inject position, then in the load position with the pump running until the pressure drops. If the problem is in the loop, reverse the loop and use pump pressure to blow the plug out into a beaker. 

By backward calculation from the GPDC correlation, based on average performance of the packing at 0.5, 1.0, and 1.5 in of water pressure drop per foot of packed depth (1). This method proved un-... 

To illustrate the validity of the models presented in the previous section, results of validation experiments using lab-scale BSR modules are taken from Ref. 7. For those experiments, the selective catalytic reduction (SCR) of nitric oxide with excess ammonia served as the test reaction, using a BSR filled with strings of a commercial deNO catalyst shaped as hollow extrudates (particle diameter 1.6 or 3.2 mm). The lab-scale BSR modules had square cross sections of 35 or 70 mm. The kinetics of the model reaction had been studied separately in a recycle reactor. All parameters in the BSR models were based on theory or independent experiments on pressure drop, mass transfer, or kinetics none of the models was later fitted to the validation experiments. The PDFs of the various models were solved using a finite-difference method, with centered differencing discretization in the lateral direction and backward differencing in the axial direction the ODEs were solved mostly with a Runge-Kutta method [16]. The numerical error of the solutions was... 

For compressible flows, the pressure drop can be calculated for both forward and backward directions. However, the forward pressure drop calculation is more reliable than the backward calculation. 

The heat gain/loss calculation has been disabled for backward calculation of pressure drop. 

In the course of an inleakage of a gas stream on a liquid surface the dint (plunge basin) in a liquid, which depth depends on a dynamic pressure of a gas stream is formed. Over the range, speed of a gas stream from 5 to 10 m/s depth of a dint is insignificant. Wave formation on a liquid surface has quiet character and fades on some distance from an axis of an accumulating gas stream. At speed of a gas stream more than 10°m/s wave formation is accompanied by partial break-down of drops of a liquid by a backward jet of a gas stream. At the further increase in speed of a gas stream intensity of a tip leakage increases. 

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