Excessive energy consumption identified by TEAM software

By introducing TEAM's Sigma monitoring and targeting (M&T) software to its Milton Keynes site, Rexam Beverage Cans is monitoring its electricity and water more effectively and has seen significant gas savings.

Background

Rexam Beverage Cans is a multi-site manufacturing company with 20 locations across Europe and Asia. The Milton Keynes site employs over 150 people and operates a round-the-clock operation that produces over 4 million aluminium cans a day. Rexam Engineering Assistant Garvin Chung summarises the site's energy usage: "The site uses over 30 Gwh of gas and electricity and 200,000 gpm of water per year. It has three production lines which are all extremely energy intensive."

TEAM Sigma software

Rexam wanted to improve the tracking of energy use across the company and to be able to benchmark sites against each other. The company required M&T software which would interface with their metering system. TEAM Sigma and the Sigma HF module met the specification.

Sigma HF enables Rexam to record, monitor and analyse consumption more closely. Garvin explains, "There are multiple ovens on each production line and up to three burners per oven. Each burner has been sub-metered and is now logged through TEAM's software. The software has been essential for detecting discrepancies at various stages of the manufacturing process, which would otherwise go unnoticed.”

TEAM Sigma savings
Gas

The cans are washed and rinsed with de-mineralised water and passed through a drying oven, which is fired with natural gas. TEAM Sigma is used to monitor the energy performance of the ovens.

Garvin explained: "During a two week period we noticed that TEAM Sigma had thrown up some major exceptions in the half-hourly data. The data indicated that 50% more gas was being consumed compared to normal. After some investigation we discovered that a gas control valve was not actuating correctly. As soon as the valve was repaired, consumption went back to normal."

"Without using TEAM Sigma HF it would have been difficult to identify where we were overspending significantly on our gas. Post calculations indicated that we could have been faced with a £40,000 overspend, equivalent to an additional 3,000,000 kWh per annum, if this exception had not been picked up."

Electricity

A good example of how Rexam uses Sigma to pro actively analyse consumption and drive forward improvements is a project involving the site's air compressors. Garvin said: "A large proportion of the site's electricity is consumed by air compressors. Good energy management practice recommends that low-pressure air compressors should be installed as an energy saving measure. We decided to replace some of our compressors and use Sigma to monitor their efficiency. We are still in the process of implementing this project and are expecting Sigma to present some interesting results.”

Water

Rexam has made a commitment to the Integrated Pollution Prevention Control (IPPC) and as part of an agreement with Milton Keynes Council, a water efficiency audit was conducted.

The audit included all the equipment that consumed water, however, it was the findings surrounding the
assembly line washers that provided the most surprising results.

Garvin said: "The cans are automatically conveyed to the washer where they are cleaned and etched in a multi-stage process using acidic solutions. On average, 560m of water is used by the washers per day. Sigma highlighted that each production line was using different amounts of water and that the washers were not automatically switching off during maintenance periods. New procedures were put in place to rectify these anomalies.”

Garvin concluded: "The work we have undertaken indicates that M&T software is essential for detecting waste. TEAM Sigma makes it very easy for us to compare the performance of each production line and take the appropriate measures to help make valuable cost and energy savings.”

Additional work

Rexam has also benefited from TEAM's partnership with Cranfield University. A recent project involved a student using Sigma to apply detailed analysis techniques at the site. Benjamin Brullon carried out the work as part of his MSc Process Systems Engineering.

The aim was to improve the utilisation of Sigma at the site and learn more about using M&T software efficiently in a manufacturing environment. Exception reports from Sigma were used to carry out an analysis of the Specific Energy Requirement (SER). This valuable exercise involved calculating the amount of energy needed to produce a certain number of cans and determining whether targets were being met. The SER analysis was carried out for gas and electricity and was also applied to each production line separately.

The achievements included:

• Reorganisation of the database and the configuration of the software.
• Reduced energy consumption by fixing targets and reporting system with Sigma.
• SER analysis in order to improve knowledge of site energy consumption and ability to further compare production lines.
• Better understanding of the relationship between energy consumption and production through regression analysis.

Sigma has been reconfigured to take into account the findings of the thesis. This includes modifications to the database and creation of new variables for the SER and target-setting.