Page 293 - Chemical engineering design

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CHEMICAL ENGINEERING
Estimated solvent loss 10 kg/d; price £400/t. Plant attainment 95 per cent.
Estimate the capital investment required for this project, and the annual operating cost;
date mid-2004.
Solution
Purchased cost of major equipment items.

Absorption column
Bare vessel cost (Figure 6.5a) £21,000; material factor 1.0, pressure factor 1.1
Vessel cost D 21,000 ð 1.0 ð 1.1 D £23,000
Packing cost (Table 6.3) £840/m 3
Volume of packing D /4 ð 12 D 9.4m 3
Cost of column packing D 9.4 ð 840 D £7896
Total cost of column 21,000 C 7896 D 28,896, say £29,000

Recovery column
Bare vessel cost (Figure 6.5a) £26,000; material factor 2.0, pressure factor 1.0
Vessel cost 26,000 ð 2.0 ð 1.0 D £52,000
Cost of a plate (Figure 6.7a), material factor 1.7 D 200 ð 1.7 D £340
Total cost of plates D 35 ð 340 D £11,900
Total cost of column D 52,000 C 11,900 D 63,900, say £64,000

Reboiler
Bare cost (Figure 6.3a) £11,000; type factor 0.8, pressure factor 1.0
Purchased cost D 11,000 ð 0.8 ð 1.0 D £8800

Condenser
Bare cost (Figure 6.3a) £8500; type factor 0.8, pressure factor 1.0
Purchased cost D 8500 ð 0.8 ð 1.0 D £6800

Cooler
Bare cost (Figure 6.3a) £4300; type factor 0.85, pressure factor 1.0
Purchased cost D 4300 ð 0.85 ð 1.0 D £3700

Solvent tank

Purchase cost Table 6.2 D 1400 ð 35 0.55 D £9894, say £10,000

Product tank
Purchase cost same as solvent tank D £10,000