Energy-Saving Case Studies in Metal Manufacturing

The following cases record cleaner production research in the metal products industry during 1999–2000. The results cover materials and energy efficiency as well as waste reduction, illustrating a broad approach to improving production.

VINAPIPE: galvanised pipe production

• Reported production scale: 15,000 tonnes per year.
• Investment cost: VND 191 million.
• Savings reported by the study: VND 3,663 million per year.
• Zinc consumption fell from 120 to 93 kg per tonne of product, a reduction of approximately 22%.
• The study also recorded a reduction in acid discharged to the environment.

Nam Dinh Steel Wire Mesh Joint Stock Company

The study focused on cleaning operations in galvanised wire production, at a scale of 9,000 tonnes per year.

• Investment of VND 320 million; savings of VND 139 million per year.
• Low-quality products decreased by 39% and products requiring reprocessing by 47%.
• Consumption fell by 2% for HCl, 2% for iron, 4.6% for electricity and 13.3% for coal.
• According to the original figures, wastewater pH increased from 4.5 to 5.0, wastewater volume decreased by 3% and gaseous emissions decreased by 70%.

Interpreting the results

Both studies were presented with support from the Vietnam Cleaner Production Centre. The figures are historical and have not been adjusted to current prices. Financial benefits include the broader results of cleaner production, rather than electricity savings alone. Companies should carry out their own surveys and calculations before applying the measures.

Documents, related articles and support

• VINAPIPE
• Nam Dinh Steel Wire Mesh Joint Stock Company