Some kind of “high-efficiency”? ? Discussion on the heat transfer efficiency of tube flue gas heat exchangers

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I remember that an “efficient” system was used in a 300,000-ton smelting flue gas acid production plant? ? For tube heat exchangers, the specification states that this type of heat exchanger has a high K value; the designed cold-side K value is 31.5. While conventional heat exchangers require two units connected in series, this one? ? One high-efficiency heat exchanger is sufficient. After the above device is put into operation, the K value fails to meet the requirements during the initial stage of operation (which corresponds to the clean-up phase). Of course, at that initial stage our focus was on getting the process up and running, and we did not pay much attention to the heat transfer efficiency of this \"highly efficient\" heat exchanger. After streamlining the process, it was found that the electric furnace at the fourth-stage inlet could not be disconnected; the outlet temperature on the SO2 side of this \"high-efficiency\" heat exchanger differed by 50 degrees from the designed value! Inviting the doctoral supervisor from a certain university (which is also a **key research center for energy conservation**) to come on site several times did not solve the problem; the electric furnace still had to be used, and the electricity cost over the course of a year was enough to purchase another heat exchanger. At least regarding the heat transfer efficiency issue of that heat exchanger, we believed at the time that it was most likely caused by an insufficient heat transfer area. However, later on, the same type of heat exchanger was used in a 400,000-ton pyrite processing plant; at the owner’s insistence, the heat exchange area was increased, but heat transfer still did not meet the requirements! Recently, upon thinking about those two examples, I came to the conclusion that this \"efficient\" heat exchanger still requires two units connected in series to solve the problem! This post was last edited by in the blink of an eye on 2009-4-12 22:40]