Regarding the feed issue of the extraction distillation tower
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Two questions; I hope experts can help answer them – I’ll give higher scores if that’s the case. 1. The temperature of the sensitive plate in the extraction distillation tower is used as a key parameter to control the quality and yield of the product. What methods are employed to regulate the temperature on this sensitive plate? Bottom temperature of the tower? 2. The extraction distillation column is a thermally balanced column; changes in the ratio of non-aromatics to benzene in the feed will lead to changes in the feed composition, thereby affecting the thermal balance of the extraction distillation column (that is, the differences in the heat capacities of non-aromatics and benzene). What is the impact of feed composition on the column’s thermal balance?
Decide whether to adjust the bottom temperature based on the column pressure and feed composition
For example, how should the bottom temperature of the tower be adjusted when the benzene content in the feed increases? Do you have practical experience?
Basically, the temperature at the bottom of the tower determines the concentration of the components there; if the temperature at the bottom is high, then the concentration of heavier components is high, while conversely, the concentration of lighter components is high. Conversely, the higher the proportion of reagents, the higher the temperature as well; generally, in systems with backflow or reflux, the temperature is controlled to be lower, and the amount of reflux also serves as a means to achieve this.
There are many factors that affect the temperature of the sensitive tray at the top of the tower, but the most direct and effective ones are, first, the flow rate of the cold reflux; secondly, the temperature of the cold reflux medium, the temperature at the bottom of the tower, the pressure at the top of the tower, and so on
As for the second question you raised, the composition of the feed material – which is simply divided here into aromatic and non-aromatic substances – will definitely result in different bottom temperatures of the tower. Simply put, it’s just a matter of determining how much needs to be steamed away
Is it the benzene extraction and distillation process from the Institute of Petrology? The function of the extraction distillation tower is to separate benzene from non-aromatic compounds, with the requirement that the solvent-rich stream have a non-aromatic content of less than 1000 ppm ； Residual oil: benzene content below 0.5%, solvents at less than 1 ppm. Main operating parameters of the extraction distillation tower and their influences (specific details may vary depending on the equipment; provided for reference only). Tower pressure: must be maintained at a stable level. Pay attention to the pressure difference between the two sections within the tower (operate in accordance with the process package). Feed composition: benzene content of over 25%, which should be kept as stable as possible. Solvent ratio: 2.8–4.5 (adjusted based on the benzene content in the feed). Reflux ratio: R/D ~ 0.2. Solvent recovery is involved here, which differs from conventional distillation. Bottom temperature of the tower: 172–175°C; temperature of the sensitive plates: 18–28°C. The temperature difference between adjacent plates in the sensitive zone should be 2–3°C. An upper limit warning should be set for the temperature of plate #41, with a recommended value of 100°C; a lower limit warning should be set for the temperature of plate #23, with a recommended value of 110°C (the extraction distillation tower has a total of 86 plates). The role of solvent temperature and the temperature difference for solvent heat exchange is to maintain stability in the heat content of the feed. A slight heat imbalance may occur, and the means of adjustment include steam usage, solvent ratio, and solvent temperature. It is necessary to try different approaches, make adjustments, and observe the results, gradually finding the most effective method.
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This post was last edited by fye002 on 2015-12-20 at 23:34. It involves the single-benzene extraction distillation technology developed by the Institute of Rock Mechanics. For some reason, there is no process package available, which makes things quite difficult to handle. What is the impact of the feed temperature on the temperatures of the upper and lower trays in the tower? How do changes in the feed composition affect the temperatures of the upper and lower trays at the feed inlet? Thank you very much, looking forward to your reply!
To understand this issue, you first need to know what determines the temperatures in the upper and lower sections of the feed inlet. In daily operations, the solvent ratio should be adjusted promptly.