Capital and total cost targets for mass exchange networks - Part 1. Simplecapital cost models

This paper presents a method for targeting the capital and total cost of a mass exchange network. This part of the paper considers stagewise systems a nd uses a simplified capital cost correlation in order to convey the fundam entals. The method starts by determining the number of stages required, usi ng the y - x composite curve plot presented previously, and then converts t his to a capital cost. This target is combined with utility targets to give a target for the total annual cost. Simple design guidelines are presented , which allow these targets to be approached to within a few percent. The m ethod is applied to a coke-oven gas sweetening example, which is a case inv olving two mass separating agents (MSAs) which do not overlap. It is also a pplied to an example involving phenol removal, in which there are overlappi ng MSAs. A final example deals with multicomponent transfer by extending th e coke;oven gas problem. The paper introduces a new graphical tool, the y - y* composite curve plot, for handling systems with overlapping MSAs. The p aper demonstrates that, contrary to previous belief. using the minimum numb er of units does not necessarily lead to a minimum cost design. (C) 2000 El sevier Science Ltd. All rights reserved.