Page 240 - Fluid Catalytic Cracking Handbook

208 Fluid Catalytic Cracking Handbook

operated unit. Use of more cost-effective changes could achieve the
same return as expensive revamp options when an optimized base case
is determined.
Any project yield improvements should be based on conducting a
series of operating test runs. The test runs should reflect "typical'*
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.
Selection of a competent engineering contractor to perform process
design and detail engineering is a key element in the overall success
of a project. Important factors to consider when choosing a qualified
contractor are:

• Successful experience in FCC technology and revamps
• Related experience held by key members of the project team
• Current and projected workloads
• Biases and preferences as they relate to proven technologies and
suppliers
• The strength and chemistry of project team members
• Range of services expected from the contractor (e.g., front-end
engineering, detailed engineering, complete E.P.C. though start-up)
• Engineering rate, mark-up, and unit cost of a "change order"

Process Design

Most companies have their own technology for the pre-design phase.
For the purposes of this book, this phase will be referred to as front-
end engineering design (FEED). FEED finalizes the process design
basis so that the detailed engineering phase can commence. In most
cases, FEED is performed by an engineering contractor, but sometimes
it is prepared internally by the refiner. The FEED package must be
sufficiently completed so that another engineering contractor can finish
the detailed engineering with minimum rework.