Page 79 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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TABLE 2.26
Comparison Between Fabric Quality Before and After
Using the Combined Process – Giza Company
Fabric characteristics Half bleach Full bleach
Whiteness index
Before 67.1 103
After 66.2 104
Wettability (seconds)
Before 3.0 2.5
After 1.5 1.5

Adopting combined processing meant that a number of stages could be
combined or eliminated entirely. Stages were optimized for greater productiv-
ity and financial savings as outlined below:
• Two hot washes and one cold wash in the half bleaching process
were eliminated.
• One hot wash, two cold washes, and three flotation rinses in the full
bleaching process were eliminated.
• Reuse of bleaching bath for the optical brightening step in full
bleaching process.

One of the greatest benefits has been in the processing time for half bleach-
ing which has been more than halved. This has increased the production
capacity from a previous maximum of 4.5 to 9.0 tons per day, an equivalent
of 480 tons per year.

Cost/benefit analysis
No capital expenditure was necessary for implementation as the benefits
were achieved by chemical substitution and process optimization. The ben-
efits were therefore immediate once the modifications were complete.
Misr Beida Dyers company produces 1,182 tons per annum of half
bleaching. It is noted that the increase in chemical costs before and after was
offset by savings in utilities and labor as indicated in Table 2.27.
A comparison of costs for Giza Spinning and Weaving before and after
modification is summarized in Table 2.28. Processing time has been consid-
erably shortened in the half bleaching process and enabled production to be
lifted by 40%. In addition to the savings on the modified bleaching process,
additional annual benefits for the increased production are realized based on
a $23 net margin per ton.

Improved fabric quality
The whiteness and absorbency were improved by the modified process at
both Misr Beida Dyers and Giza Spinning and Weaving.