How to address the issue of excessive circulating water volume in atmospheric and vacuum distillation units?
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Since the start of operation, the consumption of circulating water in my plant has been above the specified level. I’m not sure if anyone has any good solutions for this issue. The flow path of the circulating water in my plant is as follows: it enters the plant first for overhead water cooling, then for primary and secondary overhead water cooling, followed by water cooling in various side lines, and finally used for cooling the pumps
There are some ways: one is to contact the circulating water facility to run more fans in order to lower the temperature of the water entering the device as much as possible. Secondly, to improve the heat exchange efficiency of the heat exchangers through which each type of oil passes before reaching the cold cutter, it is necessary to clean them by removing the cores; this is also an acceptable option. Third, control is achieved using the outlet valve of the cold cutter; it is also necessary to clean the cold cutter when needed!
My unit hardly uses water cooling; the primary and secondary circuits rely on air cooling, while the top and bottom sections use wet air cooling. There is no after-cooling, and only a small amount of deoxygenated water is consumed. Most importantly, the water cooling system on the wax oil side streams is hardly used; this requires coordination across the entire plant. The storage tanks should be used for hot storage, and it is necessary to ensure that there are no leaks in the heating coils of these tanks. Additionally, wax oil sourced from external sources, which may contain a high amount of water, should not be received to avoid overfilling of the tanks. After all, paraffin oil is used as feed for the catalyst, and hot spots also have their advantages. So in the end, the active water cooling is reduced only once by switching to flow cooling (to control the top temperature), with this reduction taking place before the external water cooling.
Control the temperature of the outlets on each side line at the upper limit, and shut off the circulating water for each standby pump.
Consider thermal feeding of the next unit to eliminate the cooling followed by heating process.
1. For water-cooled oils, try to remove as much heat from them before they enter the water cooler (operate the auxiliary lines at a reduced level). 2. Reduce the flow rate of water in the standby pump. 3. Lower the temperature of the circulating water; as mentioned above, this can be achieved by increasing the operation of fans
The temperature after cooling in each side line should be kept as close as possible to the upper limit specified; the temperature difference in the circulation water of each water cooler must also be properly controlled
Your reduced-pressure condensation cooling system can be modified to a series configuration, with stage two and stage three; if possible, the pressure-reduction side stream can be connected in series at the end. Our plant was modified in this way, and the results were good!