Process optimisation in the mining and oil and gas sectors achieves energy efficiencies through reducing cycle times, wastage and general expenses. Practices can include redesign of processes or revisions to the layout of a plant to improve material flows and production.

In the services sector, process optimisation can be achieved by minimising delays in the service process or by the introduction of more effective system operations.

Sectors and common applications

  • Services, mining, oil and gas, manufacturing

Score

  • 67.9/100
  • Energy saving across sectors is 244 PJ (2014 estimate).

Weighting

Indicator Score
1. Energy saving and cost achievement  
1.1 Energy saving 11/15
1.2 Cost effectiveness 6/10
1.3 Prospect 5/10
2. Market contexts  
2.1 Sector energy savings 10/10
2.2 % of industry $ gross added value 4/10
3. Originality and innovation  
3.1 Originality 8/10
3.2 Innovation 6/10
4. Transferability/replicability
4.1 General applicability 4/5
4.2 Ease of implementation 3/5
4.3 Ability to integrate external resources 4/5
5. Co-benefits
5.1 Environmental 6/7
5.2 Social awareness 2/3
67.9/100

Examples

Melbourne Water Corporation introduced seasonal, opportunistic reduction in aeration blowers based on suitable process conditions. The aeration levels of the activated sludge plant at Western Treatment Plant may be reduced for short periods of time during periods of high recycled water flows and suitable process conditions, without compromising the sewage treatment objectives or licence conditions.

In these circumstances one of four large aeration blowers may be turned off for two to three months every year. This is not a permanent solution that can be relied upon every year, but is a good opportunity when conditions allow.

The aeration blowers account for 97% of the activated sludge plant (ASP) energy use.  Under certain conditions, there is the opportunity to take advantage of passive lagoon treatment processes, and reduce the amount of ASP treatment. This is dependent upon lagoon efficiency (which is impacted by temperature and plant inflows), recycled water requirements, and other operational conditions (e.g. asset availability).  In summer 2012−13, conditions were favourable to reduce ASP treatment, and flows through the ASP were reduced by around 1/3, with a corresponding decrease in energy. This operation was maintained for 64 days, between December and February.

In summer 2013−14 conditions were not favourable to reduce treatment. This was due to poorer lagoon performance, due to cooler/wetter spring conditions, as well as issues with certain recycled water supply assets.  In summer 2014−15 conditions were once again not favourable.  In winter 2014, conditions were favourable to reduce ASP treatment, and flows through the ASP were reduced, with a subsequent decrease in energy. This operation was maintained for 25 days between July and August.  In winter 2015, conditions were not favourable.

Fulton Hogan Australia Pty Ltd undertook aggregate moisture optimisation. They identified significant energy savings through supply chain management which involves obtaining dryer aggregate from quarries. There is further potential for energy and financial savings in the way aggregate is stockpiled.

Currently, aggregate is stored in open areas and directly affected by ambient moisture, with insufficient time to dry out. A number of techniques such as covering the stockpile and sloping the surface for better drainage can minimise moisture content and consumption of excess fuel in the dryer.

Other companies which have identified process optimisation as a source of energy savings include:

For more information:

Process optimisation, Sustainability Victoria

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