Compressed air system implementation reduces carbon footprint by 35%

Australian milk processor Murray Goulburn (MGC) has reduced its carbon footprint by 35% after the implementation of CompAirs recommendations in its demand side audit of the plants air system. The company has saved over AU$147,000 in energy and maintenance costs and cut carbon emissions by more than 1900 t at its Leongatha plant in Victoria after just five months.

Based on a comprehensive demand side audit of the total plant air system, the company decided to implement CompAirs audit recommendations of the factory air requirements used for both plant and packaging processes, to include new compressor units, air supply pipes and dryers.

The recommendations included replacing the four existing units with just one 300 kW Quantima compressor and leaving two units for standby air. The new system was fully commissioned in November 2007.

Funding support for the project was provided by the Victorian government<0x2019>s Enhancing Sustainability in New Investment program, run out of the Department of Innovation, Industry and Regional Development.

Detailed audit results taken before and after the installation have now been submitted to the Victorian government and prove that MGC has met its power reduction target, achieving overall energy savings of more than 35%.

“We needed to commission a completely new compressed air system that would optimise energy efficiency at every stage and CompAir Australasia has proved that it could engineer such a solution. By combining the innovative Quantima compressor with all downstream equipment, including desiccant dryers and new air distribution pipes, we have been able to reduce pressure drops and air leaks dramatically,” said Mark Gurney, group maintenance manager for MGC.

“Prior to the installation, our compressed air system was using 9.1 kW to generate each cubic metre of air per minute. Now, with Quantima, this specific power consumption has reduced significantly to just 6.12 kW/Nm³/min. In simple terms, we are now producing compressed air at best practice levels and with much better efficiency - to the effect it is now taking 33% less power for us to generate a higher air output.”

The Quantima compressor has a centrifugal compression assembly that consumes significantly less power than conventional technologies.
It has only one moving part, the rotor shaft, so there is no friction contact that can result in energy losses and performance degradation over time. In addition, the compressor also has a variable-speed drive that matches airflow to plant demand for further energy efficiency.

Using CompAir’s fixed-price service agreement, MGC is also achieving maintenance/service cost savings of around 64%.

To further reduce energy consumption and its reliance on the chilled water supply, the Leongatha site is currently installing new water cooling towers. These will enable water to be taken straight into the process, which can be up to 8% more energy efficient than using a separate factory chiller to cool the mains water. CompAir is currently working with MGC to enable the feed from the new water supply to the compressor, a project that will be completed in the next few months. This project is likely to save another 71 kW of installed power, yielding an additional $40,000 in power savings and 677 t of CO₂ savings per annum.

Mark Gurney concludes, “Instead of simply replacing one or two of our existing compressors, we chose to install a complete new system that would deliver a low cost of ownership, with the maximum energy savings possible. We are very pleased with the results. After only five months, the Quantima compressor has already delivered the energy-saving and CO₂ footprint reductions that we expected. Overall the project will pay back, pre tax, in 22 months.”