Page 30 - Sustainability in the process industry

I n t r o d u c t i o n a n d De f i n i t i o n o f t h e F i e l d 7

1.4 Balancing and Flowsheeting Simulation
as a Basis for Optimization

Balancing reconciliation and flowsheeting simulation tools are
frequently used for sustainability design and savings analysis; in
fact, they have become the main tools in a process engineer’s toolbox.
These tools help engineers to develop complete material and energy
models based on measurements and/or design values and
mathematical models. Consequently, these simulation tools play an
important role in the technical and economic decision-making
activities related to the planning and/or design stage of processes
under development and to the operation of existing equipment.
A number of computer-based systems have been developed to
help process engineers calculate energy and mass balances. However,
ongoing development costs have left only a few of these systems on
the market: those whose positions have been secured by a substantial
number of sales. An early overview of flowsheeting simulation was
presented by Klemeš (1977). The balancing, data validation, and
reconciliation technology involves a set of procedures incorporated
into a software tool. Process data reconciliation has become the main
method for monitoring and optimizing industrial processes as well
as for component diagnosis, condition-based maintenance, and online
calibration of instrumentation. According to Heyen and Kalitventzeff
(2007), the main goals of this technology are: (1) to detect and correct
deviations and errors of measured data so that they satisfy all balance
constraints; (2) to use knowledge about the process system and
structure along with measured data to compute unmeasured data
wherever possible, especially key performance indicators (KPIs); and
(3) to determine the postprocessing accuracy of measured and
unmeasured data, including KPIs. More information about available
software tools is provided in Chapter 9.

1.5 Integrated Approach: Process Integration

Heat Integration is the first part of Process Integration, which
provides the design foundation for CHP systems, refrigeration, air
conditioning, and heat-pump systems. Process Integration is equally
applicable to small, medium, and large industrial sites (e.g.,
power stations and oil refineries engaged in the production of
petrochemicals). The technology answers one of the major challenges
in the design of heating and cooling systems—namely, the complexity
of energy and power integration—via a mapping strategy based on
thermodynamically derived upper bounds on the system’s thermal
and power performance. The efficient use of available heating and
cooling resources for serving complex systems of various sizes
and designations can significantly reduce energy consumption and
emissions. This methodology can also be used to integrate renewable