Revamping

Ultimately, the process might be permanently shut down or given a major revamp. This marks the end of the project, H. If the process is shut down, working capital is recovered, and there may be salvage value, which would create a final cash inflow at the end of the project. 

S. J. Stanley and R. M. Venner, "Revamp of World Scale Ethylene Unit," paper presented at Eourth World Congress of Chemical Engineers, Kadsmhe, Germany, June 16—20, 1991. 

J. A. Nachenberg, "ARS Update/Revamp Concepts," paper presented at Eighth Ethylene Forum, The Woodlands, Tex., May 15—17,1991. 

Cryogenie turboexpanders that were built and manufaetured in the 1950s and 1960s are eandidates for upgrading and revamping. While... 

One experienced turboexpander manufacturer, Mafi-Trench Corporation (MTC), has extended its business into the repair, revamping, and upgrading of machines of various origins. A brief discussion of each problem and the MTC solution follows. 

Leaving tray support rings in towers revamped with packed beds. Poor separation. Premature flooding. Installation error. There are too many examples of this for us to continue to make this one. If you are not confident enough to remove the tray support rings, don t pack the tower. 

A revamp was proposed that w ould not have worked. 

Problem Stripper computer simulation for a base case did not match test data. Proper simulation was needed for revamp design checking. 

For revamps, exchangers with the low-pressure fluid on the tubeside can sometimes be re-rated for the two-thirds rule without any equipment redesign. However, the inlet and outlet piping up to and including the isolation valves may also need to be re-rated or redesigned for the two-thirds rule. 

During regular operations to identify potential improvements for the next plant. Process improvement studies can then demonstrate the feasibility of inherent safety improvements so they can easily be incorporated into the design of the next plant or in major revamps of existing facilities. 

The heavy naphtha-Ught gas oil fractionation zone of a crude tower has to be revamped to handle 25% more capacity. Because trays would be working at high percent flooding, Gempak structured packing is condensed (Figures 9-56A-D). 

St2idig, W. P., Troubleshooting and Revamping Distillation Columns, Chem. Processing, Feb. (1989). 

A clear understanding of feed physical properties is essential to successful work in the areas of troubleshooting, catalyst selection, unit optimization, and any planned revamp. 

Compared to amorphous silica-alumina catalysts, the zeolite catalysts are more active and more selective. The higher activity and selectivity translate to more profitable liquid product yields and additional cracking capacity. To take full advantage of the zeolite catalyst, refiners have revamped older units to crack more of the heavier, lower-value feedstocks. 

This chapter addresses project management aspects of a revamp. It also provides design guidelines that can be used by a refiner in selecting the revamp components. The original driving force for a project is often a particular mechanical problem or a process bottleneck. The ultimate objective of a revamp should be a safe, reliable, and profitable operation. 

The revamp (or erection of a new unit) requires successful execution of each phase of the project ... 

Producing a statement of requirement or revamp objectives" document... 

In many cases, a refiner decides to revamp a cat cracker and employ a new technology without first identifying the unit s mechanical and process limitations. Sometimes money is spent to relieve a constraint and the unit hits another constraint almost immediately. Failure to perform a proper constraint analysis of the existing operation can result in focusing on the wrong issues for the revamp. In addition, the revamp goals must match the refinery s overall objectives. 

Any (project yield improvements should be based on conducting a senes of operating test runs. The test runs should reflect typicar operating modes. The results should be material/heat balanced. Another test run should be performed just prior to the revamp. A comparison of the results, pre- and post-revamp, should reflect no major changes in the catalyst reformulation. 

The revamp objectives, constraints, and requirements must be clearly stated in a statement of requirement document transmitted to the engineering contractor. The document should be sufficiently detailed and require minimum interpretation so as to avoid oversights and unnecessary site visits. 

Preparation of the operating manual and procedures to reflect changes associated with the revamp... 

Any mechanical revamp to improve the unit yields should always begin with installing an efficient feed and catalyst distribution system. This is the single most-important component of the FCC unit. An efficient feed and catalyst injection system maximizes gasoline yield and conversion at the expense of lower gas, coke, and decant oil and allows downstream technology to perform at its full potential. 

The process and mechanical guidelines used in designing most of the new or revamped units are summarized in Table 7-2. 

Revamp the tower internals with high-capacity trays or packing. 

Revamp of the regenerator, provided the modification costs are more than 50% of a comparable regenerator... 

Since 1977, Reza Sadeghbeigi has been involved in various aspects of cat cracking at major and independent oil companies focusing on technical services, troubleshooting, process design, and project management—including major FCC revamps. 

V. Revamping Process Designs to Ensure Feasibility of Operating Procedures. 368... 

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