Iron and Steel Case Studies

Air Products' oxygen tuyere injection system dramatically reduces coke costs for company with large iron cupola.

 

Issue: Air Products approached a company with a large iron cupola and found out their coke rate was well above the industry average and that they were utilizing some outdated operating techniques.

 

Solution: Traveling to their plant to better understand their operation, Air Products applications engineers were able to confirm that the facility could realize significant savings by upgrading to an Air Products oxygen tuyere injection system. Our equipment engineering team worked with the on-site maintenance and project team to design a system to fit their cupola and operating conditions. Once installed, we performed a full-service startup and worked with the cupola operators to optimize the system. The result was more than enough savings on coke costs to cover their entire oxygen bill, as well as optimization and productivity improvements.

Soaking pit furnace sees outstanding savings
Flame/furnace interaction and control now possible with the Air Products Uniform Heating Oxy-fuel Burner—delivers 68% fuel savings and 8% faster cycle times.
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With the help of Air Products, a cupola operator evaluates ways to improve the efficiency and profitability of their process through oxygen enrichment and reduced coke usage.

 

Issue: Escalating coke prices have put a lot of pressure on cupola operators to improve the efficiency of their process and companies are looking at alternative fuels and oxygen-based technologies to reduce their coke demand and improve their profitability.

 

Solution: Over a decade ago, substituting 5 to 10% of coke with an alternative fuel was the upper limit. Above these substitution levels, spout temperatures, melt rates, and carbon pickup were negatively impacted. Also, at that time there was only a small price differential between coke and coal, and oxygen was relatively expensive. With changing market conditions, coke can now be two or three times more expensive than alternative fuels on an equivalent BTU basis and oxygen prices have remained stable. These new dynamics, along with Air Products’ technology advancements, favor using more oxygen to reduce coke and to increase alternative fuel substitution, while maintaining stable operations.

 

Air Products is working with a cupola operator to increase oxygen enrichment and slowly reduce coke with the goal of achieving net savings of $200- $300 per hour. In addition, our proprietary advanced control systems will be leveraged to monitor key process variables, such as temperatures and gas compositions. By analyzing variables which are not typically measured on a continuous basis at most sites, our scientists and applications engineers will be able to quickly optimize the fuel and oxygen balance within the cupola to yield efficiency improvements and cost savings.

Getting to the right solution for a rotary hearth furnace
With a thorough understanding of the furnace operations, Air Products engineers identify bottlenecks and develop a customized solution to deliver results.

Issue: A company with a large rotary hearth furnace approached Air Products wanting to buy two oxy-fuel burners.

Solution: Wanting to deliver the best solution, not just make a quick sale, Air Products applications engineers engaged the customer’s operations and plant personnel to better understand the challenges they were trying to solve and to determine if they were using oxygen safely and efficiently. With a combination of our combustion experience, time at the customer facility, computer modeling, testing in our combustion lab, and mass and energy balances, we were able to understand the bottlenecks in the customer’s process. Our solution involved a combination of burners, oxygen enrichment and direct oxygen injection in different zones of the furnace. We installed temporary flow controls, burners and injectors, and demonstrated the benefits of our solution—allowing the customer to quantify the significant productivity and product quality benefits and cost savings. Based on these results, the customer decided to implement oxygen on a permanent basis.

By modifying proven technology, Air Products maximizes coke saving for a ductile iron foundry.

 

Issue: When coke prices hit record levels, Air Products specialists began looking for ways to help foundries stay competitive. Air Products identified an existing ductile iron foundry customer, that was technically progressive, had faith in Air Products’ technical ability, and could see the significant financial incentive in trying something a little different.

 

Solution: Air Products applications engineers worked to understand the specifics of the customer’s process and find a solution that was both technically and commercially suitable. An Air Products technologist drew upon the concepts of Air Products Cupola Oxygen System (APCOS), a technology developed in Europe to inject revert materials into cupolas. One critically important aspect of this technology was that it could also reduce coke consumption. Air Products equipment and advanced technology teams built on the APCOS technology with the introduction of new supersonic nozzles to enhance the efficiency of oxygen and natural gas penetration to maximize coke savings. Working closely with the customer, and tapping into a network of foundry industry resources, the technology was successfully integrated in their process, yielding significant savings. The customer has been operating the system for close to two years and is now looking to expand their use of the technology.

Going beyond just bidding on a job, Air Products applications engineers identify ways to help potential customers find not just a supply option, but the best supply option for their application.

 

Issue: Many companies thinking of utilizing industrial gas will hire an engineering firm to evaluate their requirements, recommend a solution and write an RFQ for potential suppliers to bid on.

 

Solution: At Air Products, we evaluate these opportunities from more than just a commercial perspective. By understanding the industry and the applications for industrial gas, we will often make recommendations and propose better alternative solutions for supply.

 

For example, when a startup steel plant requested a quote for an on-site generator for their mill, we initiated an exchange of information which included analyzing the customer’s expected usage patterns, operating mode, and their planned production over the first five years. This allowed us to compare several supply modes to determine what would be the most suited for their application. In this case, liquid proved to be the best option for the first several years, and enabled the customer to achieve economic savings by substituting a fixed cost supply mode with variable cost, with no loss in reliability.

 

Similarly, while assisting a steel mill considering various industrial gas supply options to replace their aging on-site plant, Air Products went the extra mile. Rather than simply quoting on the provided RFQ, we presented additional guidance that addressed operating patterns, power consumption and supplied purity. We then worked with the prospect mill to write a revised RFQ which better suited their requirements, with no guarantee that we would get the order. Fortunately, with our industry experience, superior engineering and technology, we were selected for this supply and the customer has achieved significant savings.

Stop casts and downgraded material are overcome with technical assistance and solutions from Air Products.

Issue: A steel customer was experiencing quality problems during casting which were not only causing downgraded material, but were at times also cause for halting production. Specifically, certain steel grades which are exposed to air during casting, will allow for oxide formation that leads to undesirable inclusions and premature end to casting. Their technical team requested Air Products’ assistance to find a solution.

Solution: With experience in steel making as well as cryogenic inert gas flow, we worked with the customer to set up a trial where liquid argon could be sprayed into the hot tundish prior to cast. After several site visits, design and safety discussions, we provided temporary equipment, on-site support and monitoring methodology to combat this costly problem. The trials were successful and we continued to work closely with the customer to install the permanent, simple and least-cost solution. Shortly after installation of this solution, the quality problems were not only minimized, but this new practice was standardized, resulting in significantly reduced clogging and subsequent stop casts.