Two US steelmakers will report double-digit increases in production capacity with “flameless” combustion and other oxyfuel technology from Linde North America at the AISTech 2013 Conference at the David L. Lawrence Exposition Center in Pittsburgh, Pennsylvania – held from the 6th to 9th of May.

“Operational improvements driven by oxygen-assisted steel reheating technologies are the main theme at AISTech 2013 because of the potential economic and environmental payback,” says Tony Palermo, metallurgy industry program manager for Linde North America. Some solutions, such as REBOX® HLL for rolling mills, require only a minimal investment, and solutions can be installed to existing reheating furnaces sometimes only requiring a one-day outage.

Co-presentations with Linde are slated for Wednesday afternoon, on the 8th of May:

· At 2 pm in the Energy and Utilities Committee session titled “Regenerative vs. Oxyfuel Retrofits on Reheat Furnaces,” EVRAZ Claymont Steel will report details of a 50% reduction in specific fuel consumption and 30% production increase capability achieved with Linde technology by a REBOX® oxyfuel conversion in a pusher reheat furnace.

· At 3 pm in the Pipe and Tube Committee session titled “Seamless Pipe,” Michigan Seamless Tube (MST) will report how they reduced fuel consumption by 60% and greatly improved reheating capacity and eliminated preheating with a REBOX technical solution for their rotary hearth furnace using Linde flameless oxyfuel technology.

Scheduled to present for EVRAZ Claymont Steel (Claymont, Delaware) are Rolling Mill Operations Manager Bill Taylor and Rolling Mill Superintendent Ed Gee. Scheduled to present for MST (South Lyon, Michigan) is Hot Mill Manager Thomas Sleder.

During the Expo, Linde will be showcasing its REBOX® technical solutions, including REBOX® DFI (direct fuel impingement) oxyfuel solutions for continuous annealing furnaces, REBOX® HLL and Flameless Oxyfuel for new and existing steel reheating furnaces, and OXYGON® flameless oxyfuel technology for ladle preheating and drying. Linde has been a pioneer in oxyfuel solutions since the 1990s and has performed more than 130 installations around the globe. Interest in “flameless combustion” technology from Linde (also known as ”REBOX flameless oxyfuel”) seemed to ignite, Palermo says, after ArcelorMittal Shelby (Ohio, USA) reported at AISTech 2008 a 25% increase in reheating throughput and a 50% reduction in fuel consumption — and then won the AIST Energy Achievement Award for this project in 2010.

“The presentation on the REBOX project by ArcelorMittal Shelby was also on the last afternoon of the AISTech show,” he says. Like the MST paper this year, it related to the production of seamless steel tubular products, now in high demand to satisfy the burgeoning recovery and transmission of oil and natural gas in the US, including shale gas and oil recovery. According to the US Energy Information Administration, from 2008 to 2011, US crude oil production jumped by 14% and natural gas by 10%.

Flameless oxyfuel solutions

In “flameless combustion,” both energy efficiency and more uniform heating are achieved. Linde offers several flameless oxygen-assisted heating solutions for different types of furnaces in its REBOX portfolio. 

With REBOX® HLL (High-Level Lancing) a portion of the air needed for combustion is replaced by industrial grade oxygen. Special lances are added to existing sidewall or roof-mounted burners to establish a flameless-like combustion inside the steel reheating furnace. This leads to more uniform heating, reduced NOx emissions, reduced energy use and increased production/heating.

With REBOX® DFI controlled oxyfuel flames are fired directly onto moving strip steel in large-scale continuous annealing furnaces which dramatically improves heat transfer. ThyssenKrupp Steel has incorporated the Linde REBOX DFI oxyfuel technology on two continuous hot dip coating lines and has realised up to a 30% capacity increase and enhanced removal of residue from prior rolling operations.

The REBOX portfolio includes equipment and control systems for oxygen-enrichment, oxygen-lancing, oxyfuel-boosting and 100% oxyfuel operation in reheat furnaces and annealing lines. Linde develops and produces powerful, compact and rugged oxyfuel burners needed to retrofit in existing furnaces. Linde’s new OXYGON® 400 brings oxyfuel technology to a smaller scale for efficiently pre-heating smaller refractory-lined vessels such as ladles. Linde’s flameless oxyfuel technology allows for fuel savings up to 55% compared to air-fuel, and a 25% shorter heating cycle. The compact oxyfuel burner system is easy to install on any preheating vessel. In addition to promoting more uniform heating, flameless oxyfuel effectively lowers CO2and NOX emissions.