Preparation of Mass and Energy Balances

A summary of the mass and energy balances should be presented in tabular form using a separate sheet of paper for each unit. This 

The tabular format for mass and energy balances should be familiar to students when they undertake a design project, otherwise refer to Himmelblau, 1982, p. 100 (reference at the end of this section) or Austin and Jeffreys, 1979 (see Appendix L here). The convention is to include information for streams entering the unit on the left side of the page, and 

Each sheet of the mass and energy balances should be numbered consecutively, e.g. Sheet 1 of 32 (or 1/32). The reference number for each unit (see Chapter 4) should also be included. If an energy balance is performed over several units, then the combined and summarised balance sheet may be presented. The total mass and total energy into and out of each unit should be given at the bottom of the left hand and right 

Data such as flowrates, compositions, temperatures, etc., that are summarised in the mass and energy balances should be transferred to the process flowsheet and the equipment listing (noting any amendments from the original estimates). The process flowsheet should be 

Mass balances often do not balance exactly, some error is allowable (1%, 5%, 10% ). When an exact balance is obtained, this is usually because the flow of one stream has been obtained by difference. Therefore, an exact balance does not mean that the calculations have been performed correctly  

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