Sequencing, installation

Equipment Installation Drawings. Vendor prints which show the details and installation sequencing of purchased equipment are routinely supplied to the design and construction groups. Accurately dimensioned... 

Responsibility for installation of different parts Installation procedure Installation sequence... 

The surface facilities used to perform these functions are discussed in Section 10.1, and are installed as a sequence or train of vessels, valves, pipes, tanks etc. This section... 

The Aromax process was developed in the early 1970s by Toray Industries, Inc. in Japan (95—98). The adsorption column consists of a horizontal series of independent chambers containing fixed beds of adsorbent. Instead of a rotary valve, a sequence of specially designed on—off valves under computer control is used to move inlet and withdrawal ports around the bed. Adsorption is carried out in the Hquid phase at 140°C, 785—980 kPA, and 5—13 L/h. PX yields per pass is reported to exceed 90% with a typical purity of 99.5%. The first Aromax unit was installed at Toray s Kawasaki plant in March 1973. In 1994, IFP introduced the Eluxyl adsorption process (59,99). The proprietary adsorbent used is designated SPX 3000. Individual on-off valves controlled by a microprocessor are used. Raman spectroscopy to used to measure concentration profiles in the column. A 10,000 t/yr demonstration plant was started and successfully operated at Chevron s Pascagoula plant from 1995—96. IFP has Hcensed two hybrid units. 

WulffProcess. The regenerative technique is best exemplified by the Wulff process, Hcensed by Union Carbide Corp. The furnace consists basically of two masses of high purity alumina refractory tile having cylindrical channels for gas flow and separated by a central combustion space as shown in Figure 10. Its cychc operation has four distinct steps, each of approximately 1 min in duration, the sequence being pyrolysis and heat in one direction followed by pyrolysis and heat in the other direction. Continuity of output is achieved by paired installations. 

In the past the successful operation of batch processes depended mainly on the skill and accumulated experience of the operator. This operating experience was difficult to codify in a form that enabled full use to be made of it in developing new designs. The gradual evolution of better instmmentation, followed by the installation of sequence control systems, has enabled much more process data to be recorded, permitting maintenance of process variations within the minimum possible limits. 

The performance of a centrifugal compressor (discharge to suction-pressure ratio vs. the flow rate) for different speeds is shown in Fig. 11-87. Lines of constant efficiencies show the maximum efficiency. Unstable operation sequence, called surging, occurs when compressors fails to operate in the range left of the surge envelope. It is characterized by noise and wide fluctuations of load on the compressor and the motor. The period of the cycle is usually 2 to 5 s, depending upon the size of the installation. 

This is a highly recommended method of capacitor switching for installations that are large and require very fine monitoring and correction of p.f. with the smallest number of banks. The entire reactive requirement is arranged in only a few steps yet a small correction up to the smallest capacitor unit is possible. The relay is sequenced so that through its binary counter the required switching is achieved in small steps, with just four or six sets of capacitor units or banks. The operation of the entire sequence can be illustrated as follows ... 

When used to identify and evaluate significant risk contributors, as well as to assess the consequences of accident sequences, the PSA provides a comprehensive framework for making many types of decisions regarding reactor design, operation, and siting. These and other appi ications can be facilitated by the rational evaluation of the risks associated with a particular installation. 

Accident Sequence Modeling using a logic model for the facility was developed. The model included all initiators of potential accidents and the response of the installation to these initiators. Specific accident sequences are defined in event trees consisting of an initiating... 

Figure 51.3 provides an example of a typical work breakdown stmcture. The major divisions define specific, logical task groupings as well as the cost-accounting classifications. In the example, cost should be acquired for the preparation of the foundation, installation and final com-misioning of the pump and motor. In addition, each of the sub-tasks that comprise these classifications are logical groups of tasks that must be completed in sequence and by different work classifications. 

Process Schematic. The final installation in our main production sequence will be the recycle of reagent salts. There are quite a number of options involved in recycling reagents from nearly every operation. Figure 12 shows the process schematic where the three major salt recycle steps are highlighted by heavy lines. 

Alkylation of cyanohydrin acetonide 79 with the iodide 78 proceeded smoothly to give pentaacetonide 80 in 70% yield (Scheme 10). This represents the entire polyol framework of roflamycoin. An eight-step sequence involving installation of the polyene, macrocyclization via Horner-Emmons reaction, and protecting group machinations, completed the first total synthesis of roflamycoin. 

In another example, a sequence of methylation-elimination-hydroxymethylation was used to install the functionality pattern found in the A-ring of taxol. The hydrazone dianion was generated and methylated at low temperature. The hydrazone was then deprotonated again using excess n-butyllithium and allowed to warm to room temperature, at which point formation of the vinyllithium occurred. Reaction with paraformaldehyde generated the desired product.290... 

Indicate one or more satisfactory oxidants for effecting the following transformations. Each molecule poses issues of selectivity or the need to preserve a sensitive functional group. Select oxidants that can avoid the installation of protecting groups. In most cases, a one-pot reaction is possible, and in no case is a sequence of more than three steps required. Explain the reason for your choice of reagent(s). 

Reaction sequence E removed an extraneous oxygen by Sml2 reduction and installed an oxygen at C(15) by enolate oxidation. The C(l) and C(15) hydroxy groups were protected as a carbonate in Step E-5. After oxidation of the terminal vinyl group, the C-ring was constructed by a Dieckmann cyclization in Step F-4. After temporary protection of the C(7) hydroxy as the MOP derivative, the (1-ketoestcr was subjected to nucleophilic decarboxylation by phenylthiolate and reprotected as the BOM ether (Steps F-5, F- 6, and F-7). 

The diol was protected and the C-terminal group converted to a methyl ester in sequence B. A phosphonate group was installed at C(7) via an acylation reaction in Step C-5. Successive oxidations of the primary and deprotected secondary alcohol gave the C(l)-C(8) intermediate. 

The synthesis of the C(17)-C(24) segment also began with a diastereoselective boron enolate aldol addition. The adduct was protected and converted to an aldehyde in sequence H. The terminal diene unit was installed using a y-silylallyl chromium reagent, which generates a (3-hydroxysilane. Peterson elimination using KH then gave the Z-diene. 

The reaction of 5a-bromo-a-tocopherol (46) with amines was further elaborated into a procedure to use this compound as a protecting group Toe for amines and amino acids (Fig. 6.35).62 The protection effect was due to a steric blocking of the amino function by the bulky tocopheryl moiety rather than due to conversion into a non-nucleophilic amide derivative, and the Toc-protected amino acids were employed in the synthesis of dipeptides according to the dicyclohexylcarbodiimide (DCC) coupling method.64 The overall yield of the reaction sequence was reported to be largely dependent on the coupling reaction, since both installation and removal of the... 

While it was felt that some of the individual issues above could be addressed using the same synthetic sequence (e.g., alternate catalysts for the reduction step) it seemed unlikely that all the above would be solvable, especially as efforts to replace sodium azide with other nucleophiles had failed. Based on this assessment the team felt it would be necessary to evaluate a fundamentally new approach to taranabant and, in particular, to look for a method for installation of the chiral centers without the intermediacy of an alcohol. 

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