What are the advantages and disadvantages of the dual-pressure method and the high-pressure process?

Are you referring to the production of dilute nitric acid? The dual-pressure method involves two different pressures in the oxidation and absorption stages: a lower oxidation pressure results in less platinum consumption, while a higher absorption pressure leads to better absorption efficiency. By using a four-in-one unit, energy consumption is reduced, and the concentration of dilute acid is increased. The full-high-pressure oxidation method uses a higher oxidation pressure than absorption pressure, results in higher platinum consumption, requires a shorter operation time, and imposes higher demands on the equipment. The concentration of dilute acid used in this method is lower than that in the dual-pressure method, but the process is shorter and the equipment investment is less.

I know what was mentioned upstairs; could you provide more detailed data? Thank you!

What was said on the 2nd floor is basically correct – the dual-pressure method allows for good energy recovery (mainly through the four-in-one unit). However, the performance of foreign units is currently better than that of domestic units. Only Shaanxi Gear produces this in China; it features medium-pressure steam output, with an acid concentration of over 60%, and the exhaust gases reach below 200 ppm without any need for treatment. Although the platinum consumption in the high-pressure process is high, the main issue is the high ammonia consumption, which is about 1 kg/t more than that in the double-pressure process for 100% nitric acid; ammonia accounts for 60–70% of the cost of nitric acid. In the United States, high-pressure processes are predominantly used due to the low cost of ammonia.

Well, let me talk about the consumption levels of the two processes currently in use in our country – the high-pressure method； Currently, oxidation at 0.8–0.9 MPa is more common in China, while Henan Shenma uses oxidation at 1.2 MPa. The basic consumption for the high-pressure method is as follows: 290–305 KG/T of ammonia. Platinum: 220–280 MG/T; electricity consumption: 365 KWH (the unit is driven by motors); auxiliary steam produced: 1.5 T/T at 1.0 MPA, with an acid concentration of 55%. The exhaust gas must undergo ammonia reduction treatment. Double-pressure system with an investment of 23 million yuan for 50,000 tons ； 0.45 oxidation. The specific consumption for 1,1 absorption is as follows ； Ammonia: 282 KG/T, platinum: 120 MG/T, electricity: 11 KWH; by-product steam: 0.3 T/T (for units operating well); the exhaust gas requires little to no treatment. Invest 90 million yuan for 100,000 tons. All investments are calculated based on domestically produced units

The original poster can take a look at the analysis of the current production and market situation of the nitric acid industry in our country: http://bbs.hcbbs.com/thread-312460-1-4.html