Pumps for recirculation

The principal advantage of self-induced spray scrubbers is the efim-ination of a pump for recirculation of the scrubbing liquid. However, the designs for high-energy service are somewhat more complex and less flexible than those for venturi scrubbers. 

The scrubbing liquid is fed into the pool at the bottom of the scrubber and later recirculated from the entrainment separator baffles by gravity instead of being circulated by a pump as in venturi scrubbers. Many devices using contactor ducts of various shapes are offered commercially. The principal advantage of this scrubber is the elimination of a pump for recirculation of the scrubbing liquid. 

Barbir F, Gorgun H (2007) Electrochemical hydrogen pump for recirculation of hydrogen in a fuel cell stack. J Appl Electrochem 37 359-365... 

Unlike a PWR, a BWR has fewer components for steam generation. Figure 6.2 shows the reactor vessel, jet pumps for recirculating feedwater, and the steam drying equipment housed inside the reactor vessel. 

The velocity profile is uniform across the entire width of the channel if the channel is open at the electrodes, as is most often the case. However, if the electric field is applied across a closed channel (or a backpressure exists that just counters that produced by the pump), a recirculation pattern forms in which fluid along the center of the channel moves in a direction opposite to that at the walls further, the velocity along the centerline of the channel is 50% of that at the walls (Fig. 11.32a, see Plate 12 for color version). Figure 11.32b (see Plate 12 for color version) illustrates an electric field generating a net force on the fluid near the interface of the fluid/solid boundary, where a small separation of charge occurs due to the equilibrium between adsorption and desorption of ions. The charge region from excess cations localized near the interface by coulombic... 

A recent processing development has been the continuous oxidizer, shown in Figure 3 (91). The charge is fed to the bottom of the column, where air is also introduced. At the top of the column the liquid overflows into a buffer tank. From this the oxidized asphalt is drawn off by means of a pump, provision being made for recirculation. 

Apply IgM MAb sample to the column (see Note 7), and recirculate through the column with a peristaltic pump for at least 2 h. 

Nuclear Boiler Assembly. This assembly consists of the equipment and instrumentation necessary to produce, contain, and control the steam required by the turbine-generator. The principal components of the nuclear boiler are (1) reactor vessel and internals—reactor pressure vessel, jet pumps for reactor water circulation, steam separators and dryers, and core support structure (2) reactor water recirculation system—pumps, valves, and piping used in providing and controlling core flow (3) main steam lines—main steam safety and relief valves, piping, and pipe supports from reactor pressure vessel up to and including the isolation valves outside of the primary containment barrier (4) control rod drive system—control rods, control rod drive mechanisms and hydraulic system for insertion and withdrawal of the control rods and (5) nuclear fuel and in-core instrumentation,... 

Table 8.31 provides the added cost for a gas engine driver. These supplemental equipment items are the starter (electric motor or air piston), air tanks, air filters, cooling water pumps, and local piping. An air-cooled radiator is included in Fig. 8.10, the engine cost curve. The radiator of course requires water circulation pumps. For 500 BHP or less, the assumption is made that cooling water of the recirculated inhibited type is available from outside circulated cooling water plant... 

An electrical resistance heater with more turns at the tube ends (to compensate for heat losses) surrounds each tube. There is a vertical laminar flow hood over the loading area to minimize particle contamination of the wafers being loaded. As we can see, there are temperature controls for the furnace tubes, and a power module to provide the electrical power. When operated as a LPCVD system, a unit including both the gas flow and vacuum systems is positioned on the right side. Such a unit is shown in Figure 8. Here we can see the vacuum pumps on the left, and the mass flow controllers on the right. The vacuum pump oil recirculation systems are shown in the slide out drawers. As can be seen in Figure 9, this system, as well as most current similar systems, operate under computer control. 

A pilot plant scale starch solution, approximately 300 l, was prepared in a stainless steel container equipped with a paddle wheel electric stirrer, steam-heated coils, steam injection, an external gear pump with recirculation capability, insulation surrounding the container, a container lid, and a vent. The starch solution was prepared with the same percentage composition and duration of heating as described for the laboratory scale process. The first batch was pimped into the "sizing box" of the slasher and utilized immediately hot as a conventional yarn treatment. 

Just prior to the application of the fermented starch to the yarn, the paddle wheel was turned on for stirring and the gear pump turned on for recirculation. Both were run for 1 hr to achieve a uniform fluid mixture. 

---