Types of supports

A particular type of support assembly is selected according to the amount of restraint tolerable by the piping system and the movement to be allowed at each location. Support types ate classified as rigid, resiUent, and constant-effort hanging and resting are the two basic arrangements. 

Supported Tube. There are three types of supported tubular membranes cast in place (integral with the support tube), cast externally and inserted into the tube (disposable linings), and dynamically formed membranes. 

Enzymatic Reactors Adding free enzyme to a batch reactor is practical only when the value of the enzyme is relatively low. With expensive enzymes, reuse by retaining the enzyme with some type of support makes great economic sense. As some activity is usually lost in tethering the enzyme and the additional operations cost money, stabihty is very important. However, many enzymes are stabilized by immobilization thus, many reuses may be possible. 

The fault ctirrents also develop electrodynamic foi ces, Fii, as in equation (28.4) due to the sub-transient d.c. component. These forces play an important role in the meehanical design of the interrupting device, the load-bearing and mounting structuies for the interrupter and the bus system, and the hardware used in a switchgear assembly. All such mechanical parts, supports and hardw-are should be adequate to withstand such forces when they arise, A procedure to arrive at the ideal size of the current-carrying components, mounting structure, type of supports and hardware cte, is discussed in detail in Example 28.12. 

Double seals require some type of support system. The reason is simple. With two seals mounted onto the same shaft, one seal is the principal or primary seal and the other becomes the secondary or back up seal already installed. If the primary seal is performing its function and sealing the pumped liquid, the. secondary. seal would be running dry, overheat, burn and self-destruct. Then when the crucial moment comes, we won t have a second seal to assume the ftinctions, which was the original reason to consider a dual seal. 

Seals, particularly the restricted leakage type, require auxiliary piping, control valves, and other items. If more than a suggested schematic is to be included in the vendor s scope of supply, a statement to that effect should be made. For the oil buffered systems, if a separate oil system is required, this must be stated, and it can be detailed in the accessory section with the lube system. For dry gas seals, the type of support system must be specified. The vendor s proposal should be requested to outline materials and to... 

Beaded methacrylate polymers, poly(hydroxyethylmethacrylate), Spheron, Separon (29), and poly(glycidylmethacrylate), Eupergin (30,31), are studied extensively at the Czechoslovak Academy of Macromolecular Sciences. An addition to this type of support is poly(oxyethylene-dimethacrylate) (32). Heitz et al. (33) described the preparation of beaded poly(methylacrylates) cross-linked with ethanedimethacrylates. 

In this context, the enantiomeric pair containing the eutomer of cyclothiazide can be resolved by HPLC on cellulose-derived coated CSPs. Nevertheless, the poor solubility of this compound in solvents compatible with this type of support makes this separation difficult at preparative scale. This operation was achieved with a cellulose carbamate fixed on allylsilica gel using a mixture of toluene/acetone as a mobile phase [59]. 

Due to the small amount of SO2 in the feed, sulfation of the catalyst by the charge is very slow, and the effect of sulfur appears clearly only when Ae catalyst is sulfated separately. Dosing of SQ2 onto the solids shows that sulfur is indeed ad rbed at the surface since Cu/TiC>2 retains about 0.4 wt% S and Cu-BEA 0.1 wt% S. It is interesting to notice that the effect of SO2 clearly depends on the type of support. 

The kinetics of ethylene hydrogenation on small Pt crystallites has been studied by a number of researchers. The reaction rate is invariant with the size of the metal nanoparticle, and a structure-sensitive reaction according to the classification proposed by Boudart [39]. Hydrogenation of ethylene is directly proportional to the exposed surface area and is utilized as an additional characterization of Cl and NE catalysts. Ethylene hydrogenation reaction rates and kinetic parameters for the Cl catalyst series are summarized in Table 3. The turnover rate is 0.7 s for all particle sizes these rates are lower in some cases than those measured on other types of supported Pt catalysts [40]. The lower activity per surface... 

In this section we will discuss two studies that were performed to investigate factors which may effect particle size control (1) the type of support material and (2) the weight loading. 

Table 1 shows that catalysts prepared on the same type of support have about the same particle size distribution (PSD). Table 1 also shows that the newly developed CPS4 supported catalysts have the smallest span of particle size distribution, therefore, it has the fastest filtration rate. Filtration rate is measured by measuring the filtration time of 350 ml of 4-benzyloxyphenol debenzylation products. 

Table 1 Catalytic performance of the debenzylation reaction on different types of supported palladium catalyst. ...

Enantioselective hydrogenation of 2,3-butanedione and 3,4-hexanedione has been studied over different type of supported Pt catalysts (Pt/Al203, Pt/Si02, Pt/MCM-41) in the presence of cinchonidine (CD). Kinetic results confirmed that (i) 2,3-butanedione is more reactive than 3,4-hexanedione over all catalysts studied and (ii) both substrates have a strong poisoning effect. The kinetic results confirmed also that CD concentration close to 10"3 M is necessary to achieve both high reaction rate and enantioselectivity in the range of 55-65 %. NMR results confirmed that substrate-modifier interaction takes also place in the liquid phase. 

Table 3 Kinetic data of enantioselective hydrogenation of 3,4-hexanedione over different types of supported Pt catalysts.

Catalyst Type of support Metal content by weight (%) d , from x-ray line broadening (A) d from H2 chemisorption at room temp. (A)... 

There are two types of support systems used for fixed beds of adsorbent. The first is a progressive series of grid- and screen-layers. In this system, each higher layer screen has successively smaller openings,... 

From the data available, Hartley and Vezey (27) discussed the variable parameters. The type of support material is important. On phosphinated silica, the complex is on the outside the surface and is more accessible... 

Vertical flares These are single-burner combusters generally oriented to fire upward. The discharge point is in an elevated position relative to the surrounding grade and/or nearby equipment. Three types of support methods are used for vertical flares ... 

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