TABLE OF CONTENTS Extracting the stream data from the process flowsheet is an unspectacular, unexciting but absolutely crucial part of pinch analysis. It is not always clear-cut and sometimes alternative approaches present themselves. If the wrong method is chosen, one may either end up with impossible targets which cannot be achieved by realistic equipment, or conversely with a system which is so constrained that the only possible network is the one you already have!
At this stage we will simply cover the key aspects which will allow you to perform basic stream data extraction. Chapter 8 goes into more detail on the many practical problems which can be encountered in more complex situations. Details may also be found in ESDU (1987).
The first step necessary is to produce a heat and mass balance for the plant. This is usually a significant challenge; on real process plant, the problem with the heat and mass balance is that it almost always doesn't! Significant data reconciliation must then take place. The most important requirement is for consistency, rather than precise accuracy. Using a "balance" with serious inconsistencies will only lead to trouble when we attempt to translate the targets into practical design projects.
For a new build, a heat and mass balance can be formed from design data on flowrates and compositions and literature data on specific heat capacity, etc. For an existing plant, even if the design data is available, it will often be significantly different to...
