Targeting and design of heat fiecovery network Considering different heat transfer conditions

Abstract

To date supertargeting which is the industrial software available for targeting, designing and simulation of heat recovery network has only been able to trade off energy and capital ahead of designing and to give optimum minimum driving force (Atj^jn opt). The new targeting method suggested in this work identifies different heat transfer conditions such as boiling, condensation and sensible heat transfer in the heat recovery network and explores all the feasible stream shifting schemes to identify an alternative optimum for the given energy consumption. As an outcome, new graphical tools to screen and scope the design options at the targeting stage are introduced. It identifies ±e different optima for the different process heat recovery levels instead of identifying single optima for the entire heat recovery network. This leads to the new range targeting procedure. New insight can then be used to utilise the capital cost of the process in an economical manner. If the energy requirement is a constraint, new method suggests the range of area that can be best utilised to achieve the given energy consumption. The newly developed tools are built on the combined thermodynamic and mathematical programming approaches. Following the judgement on the optimal individual stream contributions and minimum capital at the targeting stage, the initial network structure obtained from the mathematical optimisation is next subjected to non linear cost optimisation which gives the optimum design parameters for final design. The effectiveness of the new method has been demonstrated by the case study solved.