The factory in Bissen is part of ArcelorMittal Europe Long Products – Bars & Rods, which employs more than 288 people on an area of around 50 hectares and produces more than 100,000 tonnes of industrial, fence and vineyard wire as well as metal fibres for the construction industry every year.
Idea
The energy-saving measure focussed on a significant reduction in compressed air consumption at the ArcelorMittal plant in Bissen. Compressors are often energy-intensive machines that can sometimes operate inefficiently. A thorough analysis of compressed air consumption was carried out, followed by a study to identify potential savings.
Design
In order to realise the concept of reducing compressed air consumption, various measures are being planned or have already been taken.
A study is currently being carried out to reduce the air pressure in the entire network. This approach aims to move from a paradigm of “we need pressure on the line” to a “how much pressure is really needed” by adjusting the general pressure in the network from 6 to 5 bar. This measure allows the factory to reduce energy consumption without affecting operations.
Project to identify consumers that can operate at lower pressure: A detailed analysis was carried out to determine which devices and processes can operate efficiently at lower pressure levels.
A systematic analysis of the air networks and production facilities revealed that many leaks can only be rectified when production is at a standstill.
Calculation of the savings potential for compressed air of approx. 10 % by repairing the leaks alone. In cooperation with a specialised company, a repair phase lasting several days with a production stop was planned.
Implementation
ArcelorMittal has worked with a specialised company to detect leaks in the compressed air system. The initiative was carried out during the Christmas holidays. In a three-day operation, during which production was shut down, all leaks were identified and repaired.
Result
As 60% of the leaks found were repaired during the three-day shutdown at the end of 2023 and around 65% of the remaining leaks have also been repaired since then, ArcelorMittal now estimates that they need around 7% less electricity to generate compressed air. Their goal is to eliminate at least 25% of the 35% of remaining leaks by the end of the year.
Implementation of a variable speed system on dust or fumes extractor fans
The project consists in setting up a speed regulation system on the extractor fan, activated by the machines in operation which actually require the extraction of sawdust or fumes. It involves the addition of valves and a speed variator on the extractor fan. The valves open only when the machine is operating and the fan flow rate adjusts according to the pressure.
Installing this technology, which has been available on the market for more than 5 years, the company can save significantly, up to 50%, on its electricity bills (depending on the baseline production regime) and reduce its carbon footprint. This measure is quite simple to implement, can show a rapid return on investment, and does not require a production shutdown during installation.
Use of high-performance, combination tools to reduce cycle time
The measure involves replacing simple machining tools, changing the production mode and avoiding shutdowns for unplanned maintenance and cleaning.
Use of high-performance machining tools to increase machining speeds.
Use of combination machining tools to reduce the operating time of machine tools.
Optimisation of production changes using the SMED method (Single Minute Exchange of Die – rapid tool change in less than 10 minutes).
By installing these technologies, which have been available on the market for over 5 years, companies can save up to 30% on electricity costs and reduce their carbon footprint. This measure is not simple to implement and would entail a medium-to-long term return on investment. This measure can be implemented with only a partial production shutdown during installation.
The use of articulated arms to extract dust and fumes is a system that optimises dust collection.
Dedicated profiled nozzles must be placed as close as possible to the points generating dust or fumes.
It is necessary to set up a heat recovery system on the extracted air flows with air reinjection to balance the pressures.
By installing these technologies, which have been available on the market for over 5 years, companies can save up to 20% on electricity costs and reduce their carbon footprint. This measure is quite simple to implement and would entail a medium-to-long term return on investment. However, this measure requires a production shutdown during installation.
Some older machines do not have standby mode or energy-saving mode. Companies need to purchase new machines equipped with automatic shutdown functions to save money during periods when their equipment is not in use. Here are some examples of equipment requiring ECO mode: lubrication pumps, cooling fans, hydraulic pumps, servo motors and display standby (screens).
Installing this new technology can save businesses up to 5% on electricity consumption and reduce their carbon footprint. This measure is not easy to implement and cannot be justified by the cost of energy alone. This measure requires a temporary shutdown of production during installation.
Unclogging of dust filters using a differential pressure sensor rather than a timer
Most filter unclogging installations are equipped with a timer which injects compressed air against the flow to remove the sawdust. However, this practice is energy-intensive and does not work if the filters are clogged. Instead of ordering filter unclogging, it would be better to install pressure sensors upstream and downstream of the filters. The operation entails controlling filter unclogging by differential pressure sensor (pressure difference upstream and downstream of each filter), i.e. only when the filter bags are saturated with sawdust and when unclogging is really necessary.
The use of this technology, which has been on the market for over 5 years, can save businesses up to 5% in electricity costs and reduce their carbon footprint. This measure is quite simple to implement, can show a rapid return on investment, and does not require a production shutdown during installation.
The project consists in controlling the quantity of exchanged air required in an oven, by installing a speed variator on the exhaust fan controlled by an O2 sensor and a humidity sensor.
By installing this new technology, the company may save up to 20% on gas or fuel oil consumption and also reduce its carbon footprint by around 20%. This measure is rather difficult to implement, has a quick return on investment, but requires a production shutdown during installation.
Replacement of a gas or fuel oil oven with an electric oven (baking ovens)
The project consists in replacing an existing oven running on gas or fuel oil with an electric oven using infrared to bake the product.
Installing this technology, which has been available on the market for over 5 years, can save a company up to 80% on the oven’s energy consumption, as well as considerably reduce its carbon footprint because of its transition to a new energy source (from gas/fuel oil to electricity). However, this measure is rather difficult to implement, would entail a medium-to-long term return on investment, and requires a production shutdown during installation.
Waste heat recovery in oven exhaust system (baking ovens)
The project consists in installing a heat exchanger to capture the waste heat from the oven to heat the bakery store and to produce domestic hot water.
Installing this technology, which has been available on the market for more than 5 years, will allow the company to save up to 20% on its electricity consumption as well as reduce its carbon footprint by up to 20%. This measure is rather complex to implement, would entail a medium-to-long term return on investment, and requires a production shutdown during installation.
The project involves replacing hot steam generation with humidification based on ultrasonic low-temperature water mist.
Installing this technological innovation can allow the company to save up to 95% on electricity consumption during the humidification stage, as well as 5% during the cold generation stage. This measure is not easy to implement and would entail a medium-to-long term return on investment. The measure does not require a production shutdown while the technology is being installed.
