What is the impact of water in the atmospheric and vacuum distillation process?

This phenomenon occurs only when hot water is mixed in, and it is mainly related to the ebullition of oil-water mixtures. (Could you explain this more clearly?) This post was last edited by ali2004 on 2007-12-11 at 18:33.]

In atmospheric and vacuum distillation units, high water content in crude oil increases energy consumption; in severe cases, it can even cause tower flooding! Generally, after electrodesalination of crude oil, the water content is controlled to be no more than 0.3%. It brings only harm and no benefits at all!

Due to the high latent heat of vaporization of water, a large amount of heat is absorbed during the operation of the device, which increases the load on the heating furnace, as well as the cooling requirements and energy consumption, thus having a significant impact on the device’s energy usage； At the same time, since the vaporization of water has a significant impact on the gas velocity within the distillation tower, it can easily lead to tower flooding incidents, which greatly affects stable operation ； Furthermore, a high water content also poses a burden on the treatment of wastewater discharge.

Thank you to everyone upstairs for their help! I’m still a bit confused: after water vapor is introduced at the bottom of the tower, the water inside the tower is mostly in the gas phase, with only a small amount present in the liquid phase. When the liquid phase flows to the next tray, what impact do the gas and liquid phase loads have on the tray? Especially the influence of the gas velocity in the valve hole. Since the amount is small, does the vaporization of water really have a significant impact on the gas velocity inside the distillation tower? Thank you

The steam injected at the bottom of the tower is superheated steam; in other words, no phase change occurs within the tower. Meanwhile, the feed oil or reflux contains water in liquid form, which vaporizes rapidly when exposed to high temperatures. When water vaporizes, its volume increases by a factor of 1600, which can easily lead to flooding of the tower.

I’d like to add a few more points; this is also part of my response today to a friend’s message, in the hope that it will help in accurately understanding the issue. When water enters the tower, it can be in two states: either as large water slugs or as an emulsified form. When water in these forms is heated and vaporized, the resulting steam drives the hot oil and water together to mix intensely, breaking the water phase into small droplets. Due to the large specific surface area of these small droplets, they vaporize very rapidly. At the same time, the localized formation of steam leads to a decrease in the partial pressure of oil in that area, which in turn causes some of the oil that would otherwise not vaporize to also turn into vapor. The change in volume caused by the conversion from liquid to vapor results in a sudden increase in gas volume, leading to flooding of the tower. If there isn’t enough space for the vapor and liquid to separate, the vapor and liquid phases may rise in bubbles at the point where water enters the tower, damaging the internal components of the tower. This is why allowing water to enter the tower, especially at its higher temperature areas such as the bottom, can cause significant damage to the tower.

I studied it a bit, but I don’t quite understand it

After heat exchange, both water and oil will vaporize; the difference in latent heat of vaporization leads to

It can also dissolve salts present in crude oil, such as magnesium chloride and sodium chloride. After the oil and water are mixed, the oil containing water moves toward the top of the tower; since the volume of water vapor is 10 times greater than that of oil vapor, its volume increases