Exclusive tear sets for flowsheets

Abstract

Wfe shall show in this paper that the nonredundant family of tear sets is directly related to the unique tearing of unit loops within the flowsheet. We shall discover that the inability to find a tear set which tears all unit loops exactly one time gives rise to more than one nonredundant family in the Upadhye and Grens sense. Such a discovery allows us to distinguish among nonredundant families and argue qualitatively that some of these should have better convergence properties than others.

Experimental methods in chemical engineering: Process simulation

“…Reduction of the flowsheet graph to a directed tree by elimination of all the simple cycles: A, optimal tear streams according to Barkley and Motard [15] and Christensen and Rudd [16] ; and B, optimal tear streams according to Upadhye and Grens [17] and Motard and Westerberg [18] the process flowsheet, under the additional requirement that the number of times every recycle is torn be minimum ( Figure 4).…”

“…According to Christensen and Rudd, [ 16 ] the tear streams should be selected as the set of process streams that break all the recycles in the process flowsheet and minimize the size of the recycle problem (Figure 4). According to Upadhye and Grens [ 17 ] and Motard and Westerberg, [ 18 ] the tear streams should be selected as the set of process streams that break all the recycles in the process flowsheet, under the additional requirement that the number of times every recycle is torn be minimum (Figure 4). …”

Parallel processing strategies for chemical process flowsheeting

“…Several examples from Wood (1982) have been considered. These are based on flowsheet structures taken from Sood and Reklaitis (1975) and Motard and Westerberg (1981), and involve mixers, splitter, heaters, and ideal and nonideal equilibrium-stage processes. Tables 1-4 show some typical results for each of the above initial orderings for using the BoDF structure for solving flowsheeting matrices in parallel.…”

Tearing and Precedence Ordering in Flowsheeting-an Effective Method

“…Husain (1986) has shown that the algorithm of Kehat and Shacham (1973) is not sound enough since more CPU time is consumed in simulating a flowsheet with the tear set found. Motard and Westerberg (1981) have presented a branch and bound algorithm based on the work of Upadhye and Grens (1975). However, since the algorithm uses a loop matrix, it appears not to be able to deal with complex problems like the heavy water plant (which has 109 nodes, 1974 edges and 13,746 cycles).…”

“…(a) Grens (1972, 1975) (b) Lee and Rudd (1966) 4. Motard and Westerberg (1981) 5. Gundersen and Hertzberg (1983) 6.…”