【Daily Question】11.22 True or False: Two-stage condensation vs. one-stage condensation

The total heat transfer area required for two-stage condensation is less than that required for single-stage condensation. Yes

The total heat transfer area required for two-stage condensation is less than that required for single-stage condensation

Is the total heat transfer area required for two-stage condensation less than that required for single-stage condensation? (Mistake)

The total heat transfer area required for two-stage condensation is less than that required for single-stage condensation (wrong)

The total heat transfer area required for two-stage condensation is less than that required for single-stage condensation

True or False: The total heat transfer area required for two stages of condensation is less than that required for one stage of condensation. True

The total heat transfer area required for two-stage condensation is less than that required for single-stage condensation. What are the advantages and disadvantages of each, namely \"single-stage condensation\" and \"two-stage condensation\"? “ Compared to \"one-stage condensation,\" \"two-stage condensation\" allows for a reduction in the total area of the top condenser, owing to the difference in heat transfer temperature differences between the two approaches. In the first condenser of the \"two-stage condensation\" process, since the returning oil-gas and most of the water vapor condense here, the majority of the heat load is concentrated here. Moreover, the temperature difference for heat transfer is large, resulting in a high condensation heat transfer coefficient; therefore, the required heat transfer area is significantly reduced. During the second cooling stage, the temperature difference is smaller; however, at this time only the product and a small amount of steam need to be condensed and supercooled, accounting for only a small portion of the total heat transfer load. Therefore, the total heat transfer area required for “two-stage condensation” is less than that required for “one-stage condensation”. Generally, the reflux rate in a primary distillation column is lower than that in an atmospheric pressure column; therefore, the advantages of the two-stage condensation process are more evident in atmospheric pressure columns with higher reflux rates. It is advantageous for large atmospheric-pressure plants (1.0 Mt/a and above) to adopt a \"two-stage condensation\" process. However, the reflux temperature fed into the tower under this process is high, resulting in a larger reflux flow rate compared to the \"one-stage condensation\" process, which is beneficial for the distillation of the product at the top of the tower. However, the power consumed by the pump has increased. Furthermore, the reflux is separated from the product pump and tank, making the pipelines, instruments, processes, and operations more complex. From an energy-saving perspective, in order to recover heat economically, a \"two-stage condensation\" process is also more advantageous than a \"single-stage condensation\" process. When using the \"two-stage condensation\" process, the reflux ratio should be increased appropriately; as a result, the composition of the reflux becomes heavier and the top temperature of the tower rises, which facilitates heat recovery from the tower top through heat exchange. Furthermore, the first condenser in the \"two-stage condensation\" can essentially be regarded as a theoretical tray, which helps to improve the separation accuracy of the product at the top of the tower. At the same time, hydrogen sulfide corrosion also occurs mainly in the first section, which facilitates the implementation of targeted anti-corrosion measures.

The total heat transfer area required for two-stage condensation is less than that required for single-stage condensation. ( √ )