Page 205 - Chemical engineering design

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CHEMICAL ENGINEERING
Step 5: Use the equation solving routine (E-solve with AS-EASY-AS) to solve the
equations and put the results, the flows into each unit, into a column headed “flows”,
column H in Figure 4.17; repeat for each component matrix.
Step 6: Transfer (COPY) the component flows into a table and use the SUM function
to total the flows in a column, Figure 4.18. Copy the cell references into the table not the
values. Examples, from Figure 4.18:
cell C84 contents: (H40)
cell C85 contents: (H41)
cell G84 contents: SUM(C84..F84)

A] . ... .. ..A/... .. ...B/... .. .. .C/... .. .. .D/... .. .. .E/.. ... .. .F/.. .. ... .G/.. .. ... .H
77
78
79 Flow and Compositions
80
81 Component 1 2 3 4 Totals
82 Unit
83 1 110.85 0.01 0.00 10.31 121.17
84 2 11.09 98.01 98.00 10.31 217.41
85 3 1.11 19.60 98.00 200.52 319.23
86 4 11.07 97.81 0.00 208.31 317.19
87 5 10.96 0.98 0.00 206.22 218.16
88
89
90 Unit 1 2 3 4 5
91
92 Comp.% 1 91.48 5.10 0.35 3.49 5.03
93 2 0.01 45.08 6.14 30.84 0.45
94 3 0.00 45.08 30.70 0.00 0.00
95 4 8.51 4.74 62.81 65.67 94.53
96
97 Total 100.00 100.00 100.00 100.00 100.00

Figure 4.18.

Step 7: Set up a table to calculate the percentage composition of the stream into each
unit; by copying from the table of component flows. The results are shown in Figure 4.18.
Example, from Figure 4.18:

cell C92 contents: (C83/G83) Ł 100
Step 8: Set up the calculations for any values which are design constraints. For example,
the overheads, recycle flow, from the second column which should approximate to the
azeotropic composition; see Table 4.4. The calculations giving the composition of this
stream are shown in Figure 4.19a.