Chemical manufacturing water efficiency

Opportunities for chemical businesses to reduce water use by redesigning vessels will be limited. They usually occur when new processes are being designed or existing vessels are refurbished. However, by being aware of good practice you can take advantage of opportunities when they arise.

Basic design aspects that you should focus on to reduce water use include:

• positioning valves at the lowest point to improve drainage
• replacing flat-bottomed vessels with vessels with smooth contours and no corners
• designing vessels with a cone-shaped bottom to assist drainage and cleaning
• fully enclosing vessels to reduce evaporation
• using polished stainless steel or plastic-lined vessels to make cleaning easier
• carrying out inline monitoring of the wash liquor to optimise the amount of water used

You should use high-pressure spray wash and cleaning-in-place (CIP) systems as faster washing reduces downtime and increases productivity. Using sprays as an alternative to fill-and-flush techniques can reduce water use by up to 90 per cent. You can also use brush systems with high-pressure water, while automatic and semi-automatic CIP systems enable you to optimise control.

Linking vessels and wash/holding tanks to form a closed-loop wash system - where the liquor is kept instead of being disposed of - makes it easier to reuse wash liquor, as well as reducing odours and emissions.

For more information on washing and rinsing techniques, see how to save water at industrial premises.