Advantages of Oxygen Generators in Non-Ferrous Metallurgical Industry

The use of industrial oxygen to partially or fully replace air in metallurgical smelting methods can effectively enhance the metallurgical process. It is precisely due to the emergence of this efficient and cost-effective oxygen production method that converter steelmaking and blast furnace oxygen-enriched blast have been widely adopted. It can be observed that manufacturers worldwide are embracing new smelting techniques. In fact, modern steelmaking has a significant demand for oxygen. Continuous oxygen supply not only facilitates better iron reduction but also offers the following advantages:

1. Continuous oxygen supply enables rapid temperature increase in the furnace and reduces the oxidation time of various impurities, significantly improving production efficiency.

2. The addition of oxygen accelerates the melting of furnace charge.

3. Using oxygen as an oxidizer effectively removes gases and non-metallic inclusions from the steel.

Taking the two common smelting processes as examples, the required oxygen volume and purity vary depending on the process:

1. High oxygen purity is required, with oxygen content exceeding 95%. Additionally, the working pressure must be greater than 1.3 MPa. The oxygen consumption for steelmaking is approximately 50–60 m3 per ton.

2. Blast Furnace Oxygen-Enriched Blast

Increasing the oxygen content in the blast furnace air can boost pig iron production. Data show that when coal injection per ton of iron reaches 200 kg, the oxygen content in the blast air should be between 25% and 29%. Within this range, for every 1% increase in oxygen content, pig iron production increases by 3%, and coal injection per ton of iron can increase by 13 kg. Currently, the oxygen enrichment level is mostly between 23% and 25%, with a maximum of 27%. Although the degree of oxygen enrichment is not high, the blast volume of the furnace is substantial, resulting in considerable total oxygen consumption. Therefore, a high-purity PSA oxygen generation system is required for oxygen supply. Oxygen is typically drawn in from the blower inlet, with no specific pressure requirements for the oxygen.

Process Flow of Oxygen Generators in Non-Ferrous Metallurgical Industry

Air is compressed by an air compressor and, after dust removal, oil removal, and drying, enters the air storage tank. It then passes through the air inlet valve and left inlet valve into the left adsorption tower, where the pressure increases. Nitrogen molecules in the compressed air are adsorbed by the zeolite molecular sieve, while unadsorbed gases pass through the adsorption bed, enter the gas storage tank via the left product gas valve and gas product valve. This process is called left adsorption and lasts for several tens of seconds. After the left adsorption process ends, the left and right adsorption towers are connected through an equalizing valve to balance the pressure between the two towers. This process is called pressure equalization and lasts for 3–5 seconds. After pressure equalization, compressed air passes through the air inlet valve and right inlet valve into the right adsorption tower. Nitrogen molecules in the compressed air are adsorbed by the zeolite molecular sieve, and the enriched gas enters the gas storage tank via the right product gas valve and gas product valve. This process is called right adsorption and lasts for several tens of seconds. Simultaneously, the gas adsorbed by the zeolite molecular sieve in the left adsorption tower is released back into the atmosphere through the left exhaust valve by pressure reduction. This process is called desorption. Conversely, when the left tower is adsorbing, the right tower is simultaneously desorbing. To ensure that the nitrogen released during pressure reduction in the molecular sieve is completely discharged into the atmosphere, gas is blown through a normally open backflush valve to purge the desorbing adsorption tower, expelling the nitrogen from the tower. This process is called backflushing and occurs simultaneously with desorption. After right adsorption ends, the process enters pressure equalization, then switches to left adsorption, continuing cyclically to produce high-purity product gas continuously.

In summary, although enterprises can obtain oxygen sources through purchasing or self-production, in the long run, using a PSA oxygen generation system for self-production and self-use may be a more economical approach. It is better suited for continuous and stable oxygen demand. Choosing the right oxygen source can reduce a company's oxygen usage costs, thereby lowering smelting costs and, correspondingly, increasing the company's economic benefits.