Sizing outlet piping

Outlet Pipe Sizing - Outlet piping is sized according to minimum diameter and exit velocity considerations, as follows ... 

PR Valve Outlet Piping - The outlet piping from a PR valve must be at least equal in size to the valve outlet flange. 

The outlet vapor line should be two nominal pipe sizes larger than the liquid inlet. Table 10-33 is helpful to relate exchanger size and pipe connections, although the same standards cannot apply to every design. 

This can be used to select the required size of safety valve. For the type of safety valve chosen, the next largest valve size has an actual area of 2.36x10 3 m2. The inlet and outlet pipe sizes for this valve are 0.075 m inlet and 0.1 m outlet. 

These devices are employed for fine powders (40-400 im) and also coarser particles. In the Franken or Vandenhoek inertial separators [13,14] (Fig. 4a) particle-air mixture enters from the top and falls down in the inlet pipe. The air turns abruptly to the outlet pipe inclined by about 45-50° and carries the fine particles. Coarse fraction proceeds straight down because of high inertia towards the discharge pipe. On its way this material undergoes repeated separation in a secondary air flow carrying fines into a curvilinear chamber. Then they exit via the outlet pipe with blades mounted for better air distribution. These classifiers, manufactured by Buell Co., are used for separation of pulverized limestone at cut size of 150 pra with feeds from a few pounds to 600 t/h [15], In the Buell s variant of this device [14] blades have different angles to increase the efficiency. Such devices were used for separation of 15-1000 pm particles. 

When piping the outlet to headers, flash drums, scrubbers, and so on, it is highly recommended to diverge at least one size up from the outlet piping to allow the fluids to expand this avoids unnecessary built-up backpressure and turbulences in the outlet, which creates instability in the valve. This is basically the same reason the outlet of an SRV is always one size up from the inlet (Figure 6.16). 

Outlet piping to flash tanks, scrubbers, and so forth one size up recommended... 

This shows that the piping connected to the outlet of the SRV should have at minimum an internal diameter of 54 mm. With a schedule 40 pipe, this outlet pipe would require a DN65 (3 in.) pipe which is the next standard size up. 

Outlet piping smaller than outlet size of the valve. This will cause violent turbulences when valve opens and the valve will start to chatter Make sure outlet piping is at minimum the same size as the valve outlet size. 

Constant pressure variations in inlet or/and outlet piping 1. Rearrange piping. 2. Use balanced bellow valves if pressure variations occur in outlet piping. 3. Use POSRV. 4. Use multiple valves with different sizes in stagger set. 

Narrow product size distribution, in part due to a classification effect at the top of the annulus which allows the outlet pipe to be located so as to remove primarily the largest granules. 

A classification effect at the top of the bed allows selective removal of the largest particles through the outlet pipe, yielding a relatively narrow product particle size distribution. 

The size of outlet piping required for a safety disc is not necessarily the same as the disc receptacle size. Discs frequently are sized on the basis of pressure requirements rather than capacity requirements. In such instances it is possible for the outlet piping to be smaller than the pipe size of the disc receptacle. If an arrangement of this type is desirable, the pipe diameter must be calculated on the basis of the relief capacity requirements and the maximum allowable upstream pressure. The inlet piping, however, must have an area which is at least equal to that of the receptacle in order to comply with the ASME code. 

Application of Bernoulli s equation to a simple horizontal pump or compressor with equal-sized inlet and outlet pipes leads to... 

Flashing occurs when the liquid vapor pressure exceeds the static pressure in the outlet pipe. To avoid flashing, sufficient liquid head should be available at the sump, and the outlet pipes should be correctly sized. Sizing should take into account reasonable variations in outlet flow. Pump suction lines should be as short as possible and run without loops or pockets. One troublesome experience with flashing at the entrance to a side-draw line has been reported (85). 

The computational domain has been modelled as three distinct volumes a large cylinder for the mixing tank impeller, blades and shaft and other volumes as inlet and outlet in some configurations. This allowed the mixing tank to be modelled with relatively coarse elements, while the smaller inlet/outlet pipes could have a much finer mesh applied as compared to the tank. If the domain had consisted of a single volume, a very large number of small elements would have been required to mesh it, as the mesh size would have to be chosen based on the size of the inlet/outlet pipes, impeller blade, shaft and tank wall. Meshing the three main volumes separately allows a dramatic reduction of the amount of... 

In this chapter, following topics will be discussed type of pressure relief devices, their characteristics, ASME code PRD set pressure, maximum operating pressure, contingency analysts, pressure reliefvalve and rupture disk sizing, pressure relief valve inlet/outlet piping sizing, Eind PRD selection. 

VII i. Pressure Relief Valve Inlet and Outlet Piping Sizing... 

For new piping and vapor relief, size PRV outlet piping so that total PRV outlet pressure will not reduce the K.b used for the PRV sizing, If PRV outlet piping pressure drop is loo high, it will cause PRV chatter during relief as well. PRV manufacturer s Kb versus P2/PI chart is required for this task. 

Another criterion for PRV outlet piping size is that max. vapor line velocity should be less fiian 50-75% of sonic velocity, depending on the project requirement. Sonic or critical velocity of vapor (Vc, in ft/sec) is calculated by following equation ... 

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