At AISTech 2013, MST of South Lyon, Mich., will report a 63% reduction in specific fuel consumption in its rotary-hearth billet-reheating furnace operation after retrofitting it with “flameless” REBOX® oxyfuel technology from Linde North America. The REBOX technical solution also improved reheating capacity and eliminated the need for a walking-beam furnace previously utilized to preheat larger-diameter billets.
The results will be co-presented with Linde at 3 p.m. on May 8 in the Pipe and Tube Committee session titled “Seamless Pipe.” In the presentation, MST Hot Mill Manager Tom Sleder describes project objectives, details of the implementation, and results and performance goals.
The MST mill produces approximately 39,000 tons of cold-drawn seamless carbon and alloy tubing and pipe per year. First, solid steel round billets are reheated in a rotary-hearth furnace, and then the billets are rotary pierced in a Mannesmann-style piercing mill. The rotary furnace, originally built in the late 1940s, was equipped with a traditional air-fuel heating system. As MST increased the size of billets over the years, currently ranging from 2.875 to 4.75 inches in diameter, it installed a walking-beam furnace for preheating large-diameter material prior to charging in the rotary-hearth furnace.
The REBOX oxyfuel solution proposed by Linde included a revised heating profile (see Figure 1). The faster and optimized heating rate of the actual solution reduced heating time of the 4.75-inch billets by 50% compared to the previous air-fuel heating system. It also reduced power consumption by 63%. The MST conversion included replacement of the air-fuel burners in the rotary-hearth furnace with REBOX flameless oxyfuel burners, modification of the flue-gas system and a new stack as well as installation of new baffles at the charge and discharge doors.