Page 87 - Materials Chemistry, Second Edition

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Sustainable Industrial Design and Waste Management
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Process description
Production processes in the factory are as follows:
• Seed receipt and preparation: Following receipt, the seeds are sent for
mechanical preparation. This consists of mechanical screening and
magnetic separation to remove any impurities which may be pres-
ent. Following separation are the processes of crushing, flaking, and
cooking.
• Oil Extraction: The prepared seeds are mixed with hexane in a con-
tinuous counter current system to produce a hexane–oil mixture
(miscella) and seed cake. The seed cake is separated from the miscella,
dried cooled, pressed, and used to produce animal feed. The hexane
is recovered from the miscella under vacuum (using direct and indi-
rect steam) and reused in the system. The remaining crude oil is
then cooled and sent for refining.
• Oil refining packaging: Crude oil and ghee are processed using the
following steps:
– Degumming (for sunflower seeds or soybean) and neutralization –
gums are removed in a batch process, using phosphoric acid.
Neutralization is done by adding caustic soda to remove free fatty
acids from crude oil to produce semi-refined oil.
– Bleaching – color is removed from the oil using fuller’s earth fol-
lowed by filtration.
– Deodorization – unpleasant odours are removed from oil by high
temperature vacuum distillation.
– Packaging – the reined, bleached, and deodorized (RBD) oil is
bottled in automatic filling lines.
• Soap and glycerin production: Fats are saponified in a batch process,
by mixing with caustic soda and heating with direct and indirect steam.
After saponification, soap is separated from the lye solution to be dried,
blended with additives, homogenized, cut, and pecked. Glycerin is
separated from the lye solution and distilled.

Service units
Service units include boilers, cooling towers, pumping stations, power trans-
former stand-by diesel power generators, and storage and maintenance facilities.
Energy consumption
The two main sources of energy are mazot and electricity. Mazot and solar
are used in the boilers to generate steam. Average annual consumption 15,000
tons of mazot and 600 tons of solar. Annual electricity consumption is around
10.5 million kWh.

Water consumption
3
3
The factory consumes an average of 16,800 m /day of water of which 1,800 m /
3
day is process water, and 1,500 m /day cooling and vacuum water. This