Which is more advantageous in the steel industry: cryogenic method or PSA?
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I was wondering if any of the experts here have conducted research on this: since the purity of oxygen used in blast furnaces seems not to require 99.5% O2, what if 95% O2 were produced using PSA technology for use in blast furnaces? Would this reduce the cost per unit of oxygen produced? For example, cryogenic oxygen production units can generate 7500 NM3/H of oxygen with a purity of over 99.5% O2, as well as 7500 NM3/H of nitrogen with a purity of over 99.99% N2. Given the high demand for oxygen in blast furnaces, which amounts to 7500 NM3/H, would it be more advantageous to use PSA technology to produce oxygen with a purity of 95% for use in these furnaces? Or reinvest in an air separation plant using the cryogenic method? This is because the air separation unit in the cryogenic process can also produce nitrogen, whereas the PSA process can only produce oxygen or nitrogen. If anyone has relevant data or information, please feel free to share it; I would be very grateful. Thank you. As far as I know, oxygen production in the steel industry is almost always carried out using cryogenic methods, with PSA being used rarely
So what should your export control targets be? Have factors such as pipeline contamination and instruments that cause purity deviations been considered? Does such a purity deviation have an impact on the qualified rate of blast furnace products?
The original poster has a good idea, but you have overestimated the scale of the PSA installation. In domestically mature pressure swing adsorption nitrogen production units, the processing capacity per unit is usually around 1000 Nm3/h; whereas when the nitrogen purity is 99.99% or higher, mature units have a nitrogen production capacity of only 400–500 Nm3/h. The processing capacity of a single unit of a single-series pressure swing adsorption oxygen generation system is generally also below 3000 Nm3/h. Additionally, I am not clear whether the air separation process in the steel industry operates intermittently or with adjusted conditions, or whether it runs continuously. The pressure swing adsorption process for oxygen and nitrogen production is suitable for small-scale oxygen and nitrogen generation applications where intermittent operation is possible or where condition adjustment is required ； Deep freezing is suitable for large-scale oxygen and nitrogen production applications where high gas concentration requirements, large gas consumption, and continuous operation are necessary. Damn, so much to say. . .
The PSA process isn’t yet that mature at the moment, but when we reach such a large scale, things will become increasingly easier for us. This is much easier to operate.
If iron production is considered alone, an oxygen content of 24% in the oxygen-enriched air is sufficient for him, and a pressure of around 0.25 MPa will also do. But in most cases, both iron smelting and steel making are carried out simultaneously; steel making requires a pressure of 1.4–1.8 MPa, and the flow rate is more than twice that required for steel making. Therefore, the following issues need to be considered: first, the oxygen concentration used in steelmaking ； Second, determine whether the cost of producing oxygen through pressure swing adsorption and other methods meets your needs. It is worth noting that the price and service life of the adsorbent fillers used in oxygen production methods other than cryogenic processes remain uncertain. It is better to draw on proven experience. As far as I know, the use of oxygen production methods other than cryogenic processes in steel plants does not seem to be widespread yet, so it is best to approach this matter with caution. (For reference only)
It’s impossible for PSA oxygen generation to become widespread in steel mills! The largest PSA oxygen generators currently in use have a capacity of over 30,000; theoretically, the purity of oxygen produced by VPSA is 95%. The purity is not high below 1000; PSA can be used instead. For more details, you can refer to the membrane separation section to learn about PSA
Thank you all for your responses. 1. Regarding the pressure in the blast furnace, it is 10 bar(g). 2. Current literature mentions that PSA systems can achieve a capacity of 12,000 NM3/H of O2; I wonder if there are any systems with even higher capacities. The document file is too large to be uploaded. Document: Current Status of Pressure Swing Adsorption Oxygen Generation Equipment. Author: Jia Bing, Ezhou Zhijing Air Separation Equipment Co., Ltd., Gas Separation • April 2010