Inlet design

Radial density gradients in FCC and other large-diameter pneumatic transfer risers reflect gas—soHd maldistributions and reduce product yields. Cold-flow units are used to measure the transverse catalyst profiles as functions of gas velocity, catalyst flux, and inlet design. Impacts of measured flow distributions have been evaluated using a simple four lump kinetic model and assuming dispersed catalyst clusters where all the reactions are assumed to occur coupled with a continuous gas phase. A 3 wt % conversion advantage is determined for injection feed around the riser circumference as compared with an axial injection design (28). 

FIG. 17-10 Gas inlets designed to prevent backflow of solids, a) Insert tuyere (h) clubbead tuyere. Dotr-Oliver, Inc. )... 

These inertial effects become less important for particles with diameters less than 5 /rm and for low wind velocities, but for samplers attempting to collect particles above 5 p.m, the inlet design and flow rates become important parameters. In addition, the wind speed has a much greater impact on sampling errors associated with particles more than 5 fim in diameter (4). 

Steam Turbine - A PR valve is required on the steam inlet to any steam turbine if the maximum steam supply pressure is greater than the design pressure of the casing inlet. The PR valve should be set at the casing inlet design pressure and sized such that overpressure of the casing is prevented, under conditions of wide open steam supply and normal exhaust flow. 

Since much of the vented material will be liquid, separators such as knockout pots or tangential entry separators can provide disengagement and possible recovery. Figure 5 is a typical vapor-liquid separator design found to be effective for these applications. Inlet design superficial vapor velocity is about 100 ft/sec, with sufficient volume provided to accumulate the entire reactor liquid contents. The lip on the outlet vapor line and the horizontal plate to separate the accumulated liquid are important features to prevent re-entrainment. 

The average particle size distributions for four predominantly crustal elements, Al, Si, Ca, and Ti, are shown in Figure 3. They are essentially identical. It should be pointed out that the downturn of the relative concentrations above 8 ymad (impactor stage 6) is the combined result of the actual distribution of particle sizes in the atmosphere and the efficiency with which these very coarse particles can enter (upward) into the cascade impactor. This efficiency must decrease with increasing particle size and generally depend on inlet design and wind speed. Nevertheless, it is important to note here that the patterns of the four elements are similar, implying a common aerosol source. 

Figure 6.9. On-column inlet design (Hewlett-Packard Co.-Biomedical chromatographs).

Figure 8.3. Inlet designed for OT columns and sample splitting. Courtesy of Parian Instruments.

Is this expectation really realistic In sharp contrast to a packed bed, a monolithic reactor has no flow in the radial direction there is no flow from one charmel to an adjacenf one. When the initial distribution of liquid in fhe radial direction is nonhomogeneous, this distribution will propagate down the reactor unchanged. In a packed-bed reactor, there is always some radial flow. Therefore, in a design of a monolith reactor, the inlet design is more critical than that for a packed-bed reactor. In scale-up of a monolifh reacfor, fhe reacfor inlef system has to be designed such that the distribution of fhe liquid af fhe enhance of fhe reactor is ideal. 

High rates, high selectivity inlet design and hydrod)mamics an issue... 

From the few observations cited above, it is clear that the exact design of the gas inlet has an important effect on spouting stability. However, the question of inlet construction has received insufficient attention. Indeed, it is even possible that some of the discrepancies in other aspects of spouting behavior observed by different investigators may be due to unspecified differences in inlet designs. 

The instrument used to measure total mercury by Combustion-CVAAS was the SP-3D mercury analyzer manufactured by the Nippon Instruments Corporation (NIC), Osaka, Japan. The boat inlet design of the instrument allows for analysis of either solid or liquid samples. With a separate attachment, LPG and gas samples may be analyzed. The instrument uses air that is supplied by an on board pump as the carrier gas. Before use, the air is dehumidified and passed through an activated carbon filter to scrub away background mercury. 

The boat inlet design of the NIC Combustion-CVAAS instrument system precludes the addition of an auto-sampler. Due to the necessity of minimizing the residence time of the sample in the boat prior to the analysis, an auto-sampler may not be a practical accessory for the analysis of crude oil. 

INLET DESIGN CONSIDERATIONS FOR A LIQUID-HYDROGEN PUMP... 

Inlet Design Considerations for a Liquid-Hydrogen Pump... 

Although considerable thermodynamic head is theoretically available for accelerating the fluid to the pump inlet, the volume ratio of vapor to mixture is limited. This limit must be determined experimentally to establish the limits of useful expansion. However, approximately 0.5 may be an upper limit for pump inlet design. For this volume ratio at 36.7°R, the thermodynamic head equals 130 ft. 

Fig. 3 Diagrams of electrochemical cells used in flow systems for thin-film deposition by EC-ALE. (a) First small thin-layer flow cell (modeled after electrochemical liquid chromatography detectors). A gasket defined the area where the deposition was performed, and solutions were pumped in and out through the top plate. (Reproduced by permission from Ref [41].) (b) H-cell design where the samples were suspended in the solutions, and solutions were filled and drained from below. (Reproduced by permission from Ref [42].) (c) Larger thin-layer flow cell. This is very similar to that shown in (a), except that the deposition area is larger and laminar flow is easier to develop because of the solution-inlet designs. In addition, the opposite wall of the cell is a piece of ITO, used as the auxiliary electrode. It is transparent, so the deposit can be monitored visually, and it provides excellent current distribution. The reference electrode is incorporated into the cell as well. (Adapted from Ref. [40].)...

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