A bit more than a year has passed since air separating unit 60 was put into operation in the oxygen compressor shop. Already at the stage of start-up tests it gained its estimated capacity. All the expectations confirmed in the contract with the French firm “Air Liquide”, a designer of one of the world best constructions of air separating units, have started coming to life.
According to the information of the acting head of the energy saving bureau of the chief power engineer department Stanislav Mozgovoy, the annual economy in the oxygen compressor shop after commissioning of the unit gained 165 million kW/hour, reducing the Works expenditures more than by 55 million UAH.
– Putting into operation of the new block is one of the most technically reasonable and economically well-thought-out decisions. There has never been such an economy of power resources before the commissioning of the new unit, — says the head of the oxygen compressor shop Nikolay Roman’ko. — Judge for yourselves: air separating units KtK-35 and BR-2 could work only for 3-4 months, after which shut down and repair were required. Approximately 2,5 million kW/hour were used for each start-up and stopping of the unit. But the main thing is that the degree of oxygen extracted from air on the new unit amounts to practically 100%, i.e. 60 000 m3 of oxygen is extracted from 300 000 m3 of compressed air. On the old blocks the percent of oxygen extracted from air totaled to approximately 70%. Taking into consideration the large energy-output ratio — 700 kW/hour per 1000m3 of oxygen, this is a great economy.
The advantages of the new unit are not limited by its capability of producing twice as much oxygen as the old blocks, which it has replaced. For the first time we have received a unit with controllable load from 50 up to 100% capacity in correspondence with the requirements of the blast furnace and open-hearth furnace production for the products of air separation. This is very important because air separation technologies remain quite energy-consuming even on the most modern equipment. Thanks to the new block the shop power consumption has decreased double. In 2007 the daily consumption was 1,8 mln kW/hour and in 2008 it was 1,0 mln kW/hour. In terms of money the economy totaled to 6 mln UAH/month. With the commissioning of the new unit, apart from the old blocks, part of the power consumption equipment was also put out of operation, i.e. compressors KTK-12,5 and KTK-7. Consumption of industrial water has also been reduced.
And, of course, an item of particular pride became the quality of the separated air products. In particular, oxygen purity amounts to 99,5%. Oxygen supplied from the old blocks had a concentration of 93 — 96%.
The open-hearth furnace shop workers have also felt the advantages of the new unit. Continuous supply of pure oxygen blast in the furnace during the liquid period of smelting is capable of quickening the process of steel making.
– For bath lancing the cleaner the oxygen the better. Increase of its concentration beneficially influences the steel making technology, — confirms deputy head of the open-hearth furnace shop Valentin Kharlashko.
One year work of the air separating unit 60 has brought a lot of use to the Works and also to third-party consumers in the aspect of realization of air separated products, among which are “Dneprospetsstal” and other plants on the industrial site. Their facilities are provided with oxygen, argon and nitrogen as previously through pipes.
In particular, more than 2,45 mln m3 or twice as much as in 2007 of gaseous argon was realized last year. What concerns liquefied argon the Works even exports it. Several years ago such a type of product was not even produced at the Works. And now, more than 3 mln m3 of such gas is realized.
Specialists have calculated the economic effect of the operation of such a unit. In 2008 it amounted to 93 million UAH. According to the calculations of “Giproprom” the pay-off period for the air separating unit 60 will be 4,2 years.