Just before the start of 2025, Kamet Steel's power and utility staff successfully restarted plant's main air separation unit following its major overhaul. Lasting 50 days, the major overhaul of the AKAr-40/35 was one of the largest completed at the plant under the 2024 programme.
After completing the planned repair work, specialists began preparatory pre-start activities as early as mid-December. They perform high-temperature regeneration of the adsorbent after its complete replacement. As part of the major overhaul, 68 tonnes of zeolite and 33.6 tonnes of aluminium oxide – highly dispersed materials used to remove moisture and carbon dioxide, which adversely affect the performance and quality of air separation – were loaded into the cleaned and repaired air purification vessels.
All major overhaul tasks were successfully accomplished. At the front-end purification unit, which prepares air for the separation process, the air pre-cooling system underwent cleaning and repairs, and shut-off, control and switching valves were either repaired or replaced. Another equally important set of measures included repairing turbo expanders, replacing pumping equipment, renewing unit and external pipelines, cleaning plate heat exchangers, and more.
Following the preparatory stages required under the procedure – warming up the unit and cooling down the plant’s vessels and machinery – the first oxygen was supplied to the header after the major overhaul. Once the AKAr-40/35 was back in service, the power and utility staff gradually put the KAr-30 units, which had operated in place of the main facility during its major overhaul, on standby.
"Following the major overhaul, the AKAr-40/35 was brought back to its nameplate specifications. The tests conducted on 28 December confirmed the nameplate capacity of the unit – 40 ths m3/year of nitrogen and 35 ths t3/year of oxygen. Currently, the unit operates in the pre-set mode, supplying air separation products for steelmaking. The unit’s capacity utilisation varies according to production needs. Thanks to the well-established cooperation between the oxygen compressor shop specialists and our colleagues from the blast furnace and basic oxygen shops, we determine the optimal production mode each day, preventing unproductive losses of the produced oxygen, and maintaining the efficiency of both the overhauled unit and the shop as a whole," Viacheslav HREBTESEV, head of the oxygen compressor shop.
