Piping arrangements

Complex piping systems may be required for the transfer of ehemieals, balaneing of pressures, venting, drainage, supply of serviees, ete. 

Safe operation is generally assisted by simplifieation of piping and valve arrangements, and by their identifieation, e.g. by eolour eoding or tags. Logieal arrangement ean also serve as a prompt in identifieation. 

Design of piping systems is a speeial diseipline but some guidanee is given in Table 12.10. 

Design small diameter lines to the same codes, and test to the same standards, as main lines reinforce junctions as necessary. 

Provide flexibility to allow for thermal expansion, or contraction, of pipework and connected equipment. 

Pipirtg at drums should be arranged in conjunction with nozzle locations, platform arrangements, and the 

If required, piping at horizontal freestanding drums should be supported from the shell of the drum, the platform steel, or the concrete piers supporting the drum. Piping associated with drums located within structures should be supported from the struaural steel. Exhibit 5-24 shows tjpical pipe supports at a horizontal drum, and Exhibit 5-25 shows a typical pump suaion arrangement 

Relief valves that are open to the atmosphere on low elevated horizontal or vertical drums should be positioned to allow the discharge piping to be routed 

EXHIBIT 5-21 Horizontal Dram Platform Floor Space Area Requirements 

---

Dynamic Ejfects Design must provide for impact (hydraulic shock, etc.), wind (exposed piping), earthquake (see ANSI A58.1), discharge reactions, and vibrations (of piping arrangement and support). 

This facc-to-facc double seal is quite versatile (Figure 13-21). It is reeommended in a wide range of applieations depending on the piping arrangement of its support system. 

In this chapter, we present graphic information on inadequate and correct piping arrangements. 

Inlet and diseharge pressures are defined as the stagnation pressures at the inlet and diseharge, whieh are the sum of statie and veloeity pressures at the eorresponding points. Statie pressures should be measured at four stations in the same plane of the pipe as shown in the piping arrangements. Veloeity pressure, when less than 5% of the pressure rise, ean be eomputed by the formula... 

COMPRESSOR INLET CORRECTION FACTORS FOR VARIOUS PIPING ARRANGEMENTS... 

A pressure switch located so as to sense falling pressure at the earliest moment should be used to activate the standby pump. The switch should be so connected to the system as to permit testing the startup circuit without shutting down the compressor. Figure 8-8 shows four piping arrangements. The figure at b would be the recommended method. 

Figure 8-8. Pressure gauge and pressure switch piping arrangements [1],...

Figure 10-9. Pressure indicator piping arrangements taken from a field test where only two sets of instruments could physically be installed.

For piping arrangements and vessels, the following geometric considerations are recommended. 

One of the simplest and cheapest types of heat exchanger is the concentric pipe arrangement known as the double-pipe heat exchanger. Such equipment can be made up from standard fittings and is useful where only a small heal transfer area is required. Several units can be connected in series to extend the capacity. ... 

Double-pipe exchangers-the simplest type with concentric pipe arrangement used for cooling and heating several units can be connected in series to extend their capacity. ... 

Single-pass Tube Side. For these conditions, no baffle is in either the head or the return end of the unit. The tube-side fluid enters one end of the exchanger and leaves from the opposite end. In general, these baffles are not as convenient from a connecting pipe arrangement viewpoint as units with an even number of passes in which the tube-side fluid enters and leaves at the same end of the exchanger. See Figures 10-IC and 10-lG and Table 10-1. 

Time-pass Tube Side five-pass Tube Side. These are rare designs because they require baffles in both heads, and the oudet connection is at the end opposite the inlet. This provides the same poor piping arrangement as for a single-pass unit. 

Figure 30.1 Piping arrangement for reversible flow circuit...

The inlet piping arrangement must be designed to ensure that NPSHavau exceeds NPSHreqd under all operating conditions. 

Horizontal blowdown drum/catch tank This type of drum, shown in Fig. 23-49, combines both the vapor-liquid separation and holdup functions in one vessel. Horizontal arums are commonly used where space is plentiful. The two-phase mixture usually enters at one end, and the vapor exits at the other end. To overcome reentrainment of liquid droplets, due to high inlet velocities, various devices and piping arrangements are used to provide a more uniform distribution of vapor-liquid mixtures into the separator, as shown in Fig. 23-50. For two-phase streams with very high vapor flow rates, inlets may be provided at each end, with the vapor outlet at the center of the drum, thus minimizing vapor velocities at the inlet and aiding vapor-liquid separation. 

Pipe racks normally divide a facility into major areas. For economy and process efficiencies the piping arrangement is typically a central corridor in any facility. On either side of this pipe corridor or rack the process units are provided buy its nature divides the facility into units or process areas. 

Pipe still a still in which heat is applied to the oil while being pumped through a coil or pipe arranged in a suitable firebox. 

---