A Symbiotic Relationship Defined by Operational Excellence
Located in the heart of BlueScope’s Port Kembla steelworks, the Coregas world-class Air Separation Unit (ASU) is one of the largest production facilities of its kind in the Southern Hemisphere. Not surprisingly then, Coregas is one of the largest oxygen, nitrogen and argon producers in Australia—supplying to over 60,000 customers around the country—and owns the largest merchant hydrogen production plant in Australia.
With an impeccable reputation for operational performance, Coregas supplies enormous volumes of oxygen to BlueScope for use in the steelmaking process at their Port Kembla steelworks. Of the 1,400 tonnes of oxygen that Coregas produces every day, 1,350 tonnes is used by BlueScope.
The symbiotic working relationship enjoyed by Coregas and BlueScope is one that spans over 60 years and is defined by best practice performance and reliability, and safety excellence.
According to Dave Bell (General Manager Manufacturing, BlueScope), "We are delighted with our relationship with Coregas. Oxygen is a vital raw material in the steelmaking process, and Coregas provide us with a timely supply of the large quantities we require.”
"In turn, the Coregas facility uses processed air from our blast furnace and cokemaking operations to produce oxygen, argon and nitrogen. We are very pleased and proud that these gases are able to be used throughout hospitals in New South Wales," said Bell.
How the Coregas-BlueScope Collaboration Works
Converting Processed Air into Argon, Nitrogen and Oxygen
The coke ovens and blast furnace at the BlueScope Port Kembla steelworks produce hundreds of thousands of tonnes of by-product gas, which is used to produce steam. In turn, this steam drives compressors that produce processed air, which is then supplied to Coregas. Utilising its state-of-the-art air separation technology, Coregas produces argon, nitrogen and oxygen.
Converting Steam into Hydrogen for Clean Energy
BlueScope generates two main fuels during its steelmaking process: coke oven gas and blast furnace gas. Much of this fuel is reused within the steelmaking process, such as in the hot strip mill, or to power the furnace itself. However, BlueScope uses any excess fuel to make steam, which is then supplied to Coregas to convert into hydrogen for clean energy.
Coregas uses this high-temperature steam (700°C to 1,000°C) to produce hydrogen from a methane source, such as natural gas. When placed under pressure (between 3 to 25 bar) in the presence of a catalyst, the methane reacts with the steam to produce hydrogen, carbon monoxide, and a small volume of carbon dioxide.
Unlike fossil fuels, hydrogen does not generate carbon dioxide when it is burnt. Instead, hydrogen’s only by-product is water, which dramatically reduces the impact on global warming. Affordable, clean hydrogen is the holy grail of environmentally sustainable power supply.
Coregas produces high purity hydrogen for use in applications such as metal cutting and welding applications, as well as laboratories. Working with leading vehicle manufacturers such as Hyundai, Coregas also supplies hydrogen to hydrogen car and bus schemes across the country.
A History of Operational Excellence and Safety Success
The first ASU at the Port Kembla steelworks site was purchased by BlueScope (known as AIS at the time) from Linde in 1962. Long since demolished, this ASU was a captive plant, which mainly supplied oxygen to the steelworks.
With the advent of the more modern Basic Oxygen Steelmaking processes, BlueScope purchased a second ASU from Linde in 1972, which has since been decommissioned. In 1976, an argon column was added to the plant, which was the catalyst that saw the establishment of Linde Gas in Australia. With the argon column in operation, Linde Gas was able to purchase excess argon, oxygen and nitrogen from BlueScope.
The third, and existing, ASU was commissioned in 1989. It has a production capacity of up to 1,450 tonnes per day of gaseous and liquid oxygen, gaseous and liquid nitrogen, and liquid argon.
BlueScope granted an initial ten-year contract to Coregas in 2004 for the management of the ASU, and then extended the contract for another ten years until 2024. In 2007, a nitrogen liquefier with a capacity of 200 tonnes per day was installed at the Coregas facility to support the company’s merchant growth.
With Coregas committed to continuous improvement, value, and customer service, it’s little wonder BlueScope made the decision to extend their contract.
Since Coregas assumed management of the ASU, the site has never experienced a major breakdown. The superior engineering design of the ASU delivers optimal performance and unbeatable reliability, during both day-to-day operations and planned maintenance shutdowns. A typical, industry-standard maintenance shutdown for a complex of this kind lasts two to three weeks. At the Coregas complex, just 96 hours are required.
The site also boasts 15 years free from Lost Time Injuries (LTI), demonstrating the exceptionally stringent adherence to health and safety standards.
In 2014, Air Products undertook a rigorous assessment of the Coregas Cryogenic Plant and Bulk Production Complex and declared it a “world-class facility and best-in-class operations”.
All this operational excellence is delivered in the most cost-effective manner possible; to achieve optimal operating margins, Coregas demonstrated to BlueScope that a single ASU was all that was necessary, and that the configuration would be safe and reliable.
At the time, the potential vulnerabilities of a single ASU operation included a lack of redundancy in nitrogen compression, an extended timeframe for ASU overhauls, and reduced back-up system capacity. To overcome these drawbacks, Coregas undertook several measures to ensure all necessary fail-safes were in place, installed a larger back-up system, and invested in additional equipment.
Why Oxygen is Essential to the Steelmaking Process
In every heat, or batch, of steel that BlueScope makes, they use approximately 13,500 normal cubic metres of oxygen. This is equivalent to five and half Olympic swimming pools full of pure gaseous oxygen.
This oxygen must be of an extremely high purity—99.5% pure—supplied at a high flow rate. Oxygen purity is essential in the steelmaking; the more pure the oxygen, the better quality the steel.
Oxygen is used in the steelmaking process to reduce carbon content. Molten iron contains approximately 4.5% carbon, whereas steel, such as that used to manufacture BlueScope’s COLORBOND® roof sheeting, has only about 0.05% carbon.
Oxygen is blown through a water-cooled steel lance or pipe at a rate of 55,000 normal cubic metres per hour, which is equivalent to the twice the speed of sound. This creates a thick foamy slag that is critical to ensuring the steel has the correct carbon content and chemical composition.
With their Port Kembla steelworks operating constantly 24 hours per day, it is essential that BlueScope has access to the constant, reliable supply of high purity oxygen delivered by Coregas.