Chemical Engineering December 2016 - 46

FIGURE 2. It is extremely difficult to utilize
a factored estimate for equipment costs in
pilot plants due to the large variability in
size and instrumentation requirements
for a pilot plant is to validate the system's
performance. That could mean evaluating
overall yield, efficiency, purity specifications,
impurity buildup and so on. All
of that means collecting data, and that
often means analytical data. While some
processes may be capable of utilizing
offline sample collection and analysis,
all of this data collection frequently
means online analysis. It is certainly
not out of the question for a $500,000
pilot plant to have a $250,000 process
mass-spectrometry system connected
to it - and that cost may not even include
all of the automatic sampling systems,
method development effort and
installation costs.
There may also be a need to analyze
components online inside of the process
for safety purposes. Furthermore, there
could also be a requirement for area
monitoring in enclosed operating bays
to detect toxic or flammable gases or
oxygen-deficient atmospheres.
With all of this potential for high-dollar
instrumentation, it is imperative to understand
the analytical scope and to
have considerable upfront discussion
with analytical experts. Those discussions
should include a review of the
equipment costs as well as the costs
to develop the analytical methods and
the impact on the schedule. At a minimum,
obtain a good budget quote for
any early estimates, and if possible, get
a firm quote with a performance specification
for an authorization-level estimate
40
for any complex equipment if it is a large
portion of the total costs.
Control systems. In addition to field
instrumentation, the control hardware
itself must also be taken into account.
In a modernized facility, this is typically
a centralized distributed-control system
(DCS) or possibly a slightly less complicated
programmable logic controller
(PLC). In a centralized pilot plant with
a common DCS that operates multiple
pilot facilities, the cost considerations
normally involve the number of input/
output (I/O) cards, any extra cabinets
and operating-station modifications.
Special licenses and occasionally
some additional networking may also
be required.
In a facility without a shared control
system, the cost of the control system
must be included in the cost estimate.
This is best handled by working with the
control-system vendors to obtain budget
quotes. Be sure to take into account
the need for future expansion of the system.
At an early stage of the project, it
is unlikely that you will have thought of
all of the instruments that will ultimately
be installed. Pilot plants also have a way
of growing their need for data collection
as the scope and experimental run plan
develop, so be sure to allocate adequate
room to add instrumentation later
as needed. For this purpose, consider
20% spare I/O capability as a minimum
design criteria.
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Chemical Engineering December 2016

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