Water in diesel at the bottom of the tower is removed via the diesel side stream
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This post was last edited by wzuozu on 2022-8-5 at 14:27. The diesel stream obtained from the side stream of the distillation tower enters the diesel stripping tower, with 10 kilograms of superheated steam being injected at the bottom of this tower. However, the finished diesel contains about 300 PPM of water (no free water, but the oil becomes cloudy). Previously, fuel gas was used for stripping; in that case, the diesel was free of water, but its flash point was not up to standard. Nitrogen was then used instead, and the specifications were met, but this led to the problem that the gas from the top of the distillation tower could not be used in the furnace – sending it to the flare caused the nitrogen level in the gas holder to exceed acceptable limits. Subsequently, a diesel coalescer was modified, reducing the water content to around 111 PPM. I’m not sure if the following approach would work: replacing the steam injection at the bottom of the side stream tower with a reboiler, or using medium-pressure steam instead? Ask someone with experience for advice
Edited on a mobile phone; there are a few spelling mistakes. After the indicator (exceeds standard), there is (again)
What is the withdrawal temperature on the diesel side line? If steam stripping with a reboiler is used, the bottom temperature of the tower will be higher than that in the case of side-line extraction or steam stripping. It is recommended to conduct calculations to determine whether the pressure of the medium-pressure steam used for heating the reboiler is sufficient to meet the requirements.
Diesel extraction is carried out at 260°C–270°C; the bottom residue oil (around 355°C) could be used as a heat source. This is just an idea – I’m hoping to draw on everyone’s successful methods