In September 2025, Dorogobuzh in Smolensk region (a member of Acron Group) performed a major overhaul of its ammonia unit, increasing its daily output by 100 tonnes to 2,300 tonnes or 830,000 tonnes per year.
The limiting factor in the ammonia unit upgrades, involving almost 400 specialists from contracting organisations and in-house workers, was replacing the KRES heat exchanger bundle. This key component was manufactured by Dorogobuzh mechanical repair shop.
The start-up boilers were repaired to improve safety, and the natural gas injection system was upgraded to reduce hydraulic resistance. This resulted in decreased pressure in the process line, higher compressor power and a significant boost to overall performance. Other major work included repairs to the primary reforming furnace (including local sections of the convective zone lining, the suspended vault, and the burner blocks of the auxiliary boiler) and the reactor, replacement of the steam chambers of the waste heat boilers and the methanation catalyst.
Pavel Simakov, Dorogobuzh’s Deputy Executive Director and Chief Engineer, said, ‘The technical service team at the ammonia unit faced a challenging task of preparing the equipment for repair quickly and efficiently. This involved cleaning and replacing the oil in the compressor and steam turbine oil systems, loading and recovering secondary reforming and methanation catalysts that had not been used in the process before. We also performed partial repairs to the compressor vacuum extractor, a first experience for such production facility. The increased ammonia production will ramp up commercial output due to the sustainable development of mineral fertiliser production’.
The Dorogobuzh ammonia unit with a design capacity of 450,000 tpa was commissioned in December 1979. In 2019, the company completed a major project to upgrade its ammonia production facilities. This was the first post-Soviet project implemented using Toyo Engineering Corp. technology to increase a daily output to 2,100 tonnes. Following a major overhaul in September–October 2022, Dorogobuzh increased the ammonia unit’s output to 2,200 tonnes per day. In 2025, the unit’s daily capacity reached 2,300 tonnes.