Differences between the two main switching processes
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The conventional air separation main heat exchanger consists of several plate exchangers connected in parallel; for example, a 10,000 capacity air separation unit uses 3 plate exchangers in parallel. Each plate exchanger has channels for process air, nitrogen, oxygen, and waste nitrogen, and the three plate exchangers are essentially identical to one another； Another approach is to have 3 plate types connected in parallel, but each plate type is different: Plate 1 has channels for process air, expanded air, and nitrogen; Plate 2 has channels for process air, expanded air, and oxygen; Plate 3 has channels for process air, expanded air, and contaminated nitrogen. I know that Wugang uses this process, and several small factories in Kaifeng prefer to use it. Please, fellow sailors, share the operational features of the two processes.
In external compression air separation, since the pressures of nitrogen, oxygen, and contaminated nitrogen as they exit the cold box are similar, there is not much difference in the operation of these two processes; it is only necessary to pay attention to the temperature difference at the hot end
I believe the second process solves the problem of uneven distribution in parallel plate designs, but it increases the requirements for operation.
My personal understanding is that, in the case of external compression, the second plate combination should be better, as the pressure difference is not significant. For internal compression, the first option is better; this has been well proven in practice, as it provides good distribution of cooling capacity, satisfactory heat exchange performance, and good efficiency in terms of plate utilization.
I think the same way; during external compression, the second process is more feasible, though it requires adjusting the amount of feed air allocated according to changes in product output； During internal compression, the first process has a smaller temperature difference at the hot side, resulting in slightly lower energy consumption, but the cost of the plate type increases.
This type of panel-based combination offers greater operability and adjustability, as well as better precision in control.