Zezhou Golden Autumn Foundry Co., Ltd (hereinafter referred to as Golden Autumn Foundry) completed its technological upgrading project in 2019 for the cast iron manufacturing with an annual output of 100,000 tons. In order to achieve cost reduction and efficiency enhancement, Golden Autumn Foundry equipped the foundry blast furnace with an oxygen-rich PSA oxygen unit (2500Nm3/h,80%), which was successfully put into operation in April 2020 after the BF adjustment and optimization, and has been running smoothly for half a year so far, with all the comprehensive indicators better than the expected specifications.

Golden Autumn Foundry is a major pig iron manufacturing enterprise in the Shanxi region, with an annual casting production of 60,000 tons. It currently has a 179m³ blast furnace with the blower air volume of 900m³/min. When enriched oxygen is not offered to the blast furnace, the coal injection quantity into the BF is relatively low. The ratio of molten iron to coal per ton is about 110kg/t of iron, while the coke ratio is greater than 460kg/t of iron. The high fuel cost has greatly squeezed its profit margins and at the same time, the molten iron output is difficult to grow and can only stay at about 700 tons on a daily basis.

PSA Oxygen System for Foundry Blast Furnace Can Create Considerable Economic Benefits

With a view to reduce production cost and increase molten iron output, at the end of 2018, after its management team inspected a number of foundry companies in Shanxi Province and fully studied the oxygen enrichment technology effects and process, Golden Autumn Foundry decided to adopt the pressure swing adsorption (PSA) oxygen generation technology and construct a new set of 2500/80 oxygen system for the foundry blast furnace.

The oxygen plant injects 80% enriched oxygen to the blast furnace before the blower. The capacity is equivalent to 2000Nm³/h for pure oxygen, the power consumption is 0.34kWh/m³ for 100% oxygen generation, and the oxygen enrichment rate is about 2.73%. After the acceptance, the oxygen system has been running pretty well since the start-up-the capacity reaches 2100Nm³/h, and the measured power consumption is 0.299kWh/m³ for pure oxygen generation, which far exceeds the design target. Also, during the construction period, the professional and efficient service of PKU Pioneer project team was widely praised by Golden Autumn Foundry.

The production data shows that after adopting the BF oxygen enrichment technology, the amount of coal injected per ton of iron has increased to 160kg, the coke consumption has dropped to 390kg, and the daily molten iron output has increased to more than 800 tons, an increase of about 14%. The PSA oxygen generation process has created considerable economic benefits for Golden Autumn Foundry by lowering the production costs and increasing the pig iron output meanwhile. In sum, this technical improvement project has clearly paid off.