Manifold system

If one or more clusters of single wells are required then an Underwater Manifold System can be deployed and used as a subsea focal point to connect each well. The subsea trees sit on the seabed around the main manifold (compared to the template). 

Fig. 6. Intake manifold system with a water-atomizing spray nozzle distributing to four individual cylinders. See text.

There is a need in many chemical processes for protection against propagation of nnwanted combnstion phenomena snch as deflagrations and detonations (inclnding decomposition flames) in process eqnipment, piping, and especially vent manifold systems (vapor collection systems). 

An in-line detonation flame arrester must be used whenever there is a possibility of a detonation occurring. This is always a strong possibility in vent manifold (vapor collection) systems, where long pipe runs provide sufficient run-up distances for a deflagration-to-detonation transition to occur. Figure 3-3 shows the installation of in-line arresters of the detonation type in a vent manifold system. 

One of the most widely nsed methods of prevendng deflagrations and detonations is oxidant concentration rednction. This method can be applied to process eqnipment and vent manifold systems. The prevendon of deflagrations or detonations can be accomplished by either inerdng or fnel enrichment. 

The flame propagation direction affects the type of flame arrester selected. An end-of-line or in-line deflagration flame arrester used for the protection of an individual tank may be of a unidirectional design because the flame will only propagate from the atmosphere towards the tank interior. A bidirectional flame arrester design, however, is needed for an in-line application in a vapor recovery (vent manifold) system because the vapors must be able to flow from the tank interior into the manifold, or from the manifold into the tank interior. Consequently, flame may propagate in either direction. 

With respect to detonation flame arresters in vent manifold systems, they can he located at any distance along the manifold as long as they are easily accessible for maintenance.. 

Example 1—Protective Measures for a Vent Manifold System... 

This example illnstrates several protective measnres that were provided for a vent manifold system in an actnal aromatics chemical plant. 

Fignre 9-1 is a schematic drawing of the major eqnipment and protective measnres that comprise the vent manifold system. In the system shown, the vent vapors (offgas) from the condensers of two vacnnm col-nmns are collected in a manifold which goes to the vacnnm pnmp system. From the vacnnm pnmp system, the vapors go to a seal dmm (hydranlic flame arrester), and then to the firebox of a process heater, where they are incinerated. 

FIGURE 9-1. Vent manifold system protective measures. 

Balancing of manifolded systems is often very difficult. The use of damper within the system was the generally accepted method until fairly recently. The use of dampers has not proven to be effective because they tend to fail for a variety of reasons and are difficult to keep adjusted. More recently, balancing of manifolded systems has been accomplished by use of static pressure differentials. This method has proved to be very effective, but has limitations. 

In a typical countercurrent moving-bed carbon column employing upflow of the water, two or more columns are usually provided and are operated in series. The influent contaminated groundwater enters the bottom of the first column by means of a manifold system that uniformly distributes the flow across the bottom. The groundwater flows upward through the column. The unit hydraulic flow rate is usually 2 to 10 gpm/ft2. The effluent is collected by a screen and manifold system at the top of the column and flows to the bottom manifold of the second column. The carbon flow is not continuous, but instead is pulsed. 

FIGURE 6-2 Ozone source and manifold system. Adapted from Hodgesonet al. 

The opportunity to reduce the cost per analysis point can be very important for certain applications. One option with FTIR is to use sample stream multiplexing with a manifold system. For gas-based systems this is very straightforward, and does not impose a high cost overhead. Liquid systems are more complex, and are dependent on the nature of the stream involved, and material reactivity, miscibility and viscosity are important factors to consider. As noted previously, with the introduction of new, miniaturized technologies, the hope is that newer, less expensive devices can be produced, and these can provide the needed multiplicity to reduce the cost per analysis point to an acceptable level. 

The transfer connections from the wharf piping to the vessel manifold system are typically made using one of the following ... 

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