Effect of solvent feed temperature in the dibutylene extraction DMF process on the plant
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In the DMF extraction process for butadiene, what impact does the temperature of the solvent feed have on the equipment? Could any colleagues explain this in detail? The desired control range for my equipment is 37–47 degrees; currently it is maintained at 44–45 degrees. A higher temperature can help save energy, but does it also improve the efficiency of extraction? What might happen if the temperature is raised even further?
Higher temperatures reduce the extraction capacity of the solvent. The desired separation capability may not be achieved.
This is to ensure stable temperature in the first extraction stage, so as not to affect the operation of the first extraction distillation tower. If the temperature is unstable, it can easily affect the temperature of the sensitive plate in the first extractive distillation column, thereby causing issues with the BBR operation. Moreover, the solvent should be injected very slowly during circulation, especially in winter. The temperature in Daqing is low, so when pouring solvent from the ground-level tanks into the large solvent circulation tanks, it must be done very slowly, in order to avoid affecting the temperature of the circulating solvent. Thereby ensuring the quality of the products and by-products
Reply to 1# minzhili: If one checks the DCS, it can be seen that the temperature at the point where the recycled solvent is injected into the first extractive distillation column should be similar to or equal to the temperature of the recycled solvent. This ensures that the operation of the tower is not affected. If the temperature is too high, butadiene will be lost at the top of the first extraction distillation column; the target we aim for is a loss of less than 0.3%, as a slightly higher temperature can easily lead to product loss. If the temperature is too low, it is easy for the levels of cis and trans butene at the bottom of the first extractive distillation column to exceed the specified limits
If a distillation column has been designed, it should be known that the temperature of the solvent feed is roughly equal to the temperature at the feed plate. A large temperature difference can lead to uneven heat distribution within the column. Moreover, increasing the solvent feed temperature affects the efficiency of solvent extraction, while too low a temperature results in increased energy consumption; therefore, this temperature is generally kept below 45 degrees, and it is also related to the pressure at the top of the column