Let’s analyze the manufacturing process together
Thread Content
1. An increase in pressure due to various reasons can raise the boiling point of the material, potentially leading to overheating and accidents. 2. The vacuum distillation tower is equipped with a low-vacuum alarm at the bottom of the tower. In cases where a decrease in vacuum level leads to an increase in temperature, posing an explosion risk to the material, an interlock system is installed to cut off heating of the material when the vacuum level at the bottom of the tower drops too low. I think these conclusions are all wrong; I’m not sure what others think.
For a designed and completed unit, an increase in pressure can only prevent the tower from extracting more light components; an excess of light components at the bottom of the tower leads to a decrease in the boiling point at atmospheric pressure.
The reboiler heat load determines the bottom temperature of the tower
Within a certain range, to meet the requirements of the processing process, manual control is necessary; the amount of heat transfer medium must be increased as well as the temperature at the bottom of the tower. An increase in this bottom temperature leads to a reduction in the temperature difference for heat transfer, resulting in higher pressure and an increased latent heat of vaporization. Moreover, the heat transfer area of the equipment is insufficient. From a dynamic perspective, the bottom temperature does not rise indefinitely.
Therefore, it is incorrect to apply design-based conclusions to calculation purposes without considering the capabilities of existing devices under those design conditions.
The equipment itself should be equipped with a safety pressure relief device
In vacuum distillation, as the vacuum level decreases, the temperature of the tower rises overall. If this temperature increase poses a risk of explosion, the first step is to install alarms and interlocks connected to the reboiler’s heating source. Additionally, human intervention is required to accelerate the removal of products from the bottom of the tower and to supply more feedstock in order to lower the tower temperature, while taking into account the impact on product quality. The vacuum should be restored as soon as possible.
Considering only trends without taking volume into account is ignorance; assuming y=a+b, a certain factor will cause a to increase while b decreases. It is necessary to calculate whether the changes in these two variables will lead to an increase or decrease in the total amount; it cannot be assumed simply. As pressure increases, the partial pressures of each component also increase. Based on the relationship between vapor pressure and temperature, the overall temperature of the system rises
Of course, it won’t rise indefinitely; the increase in pressure is also not unlimited. There is a relationship between pressure and temperature. At the same time, pressure is also related to entry and extraction. As the temperature rises, the production volume increases accordingly; the pressure may not increase. Conversely, an increase in pressure generally leads to an increase in the temperature at the bottom of the tower
The existing devices should be analyzed
If heated with 0.6 Mpa steam, the jacket pressure is 0.4 MPa. How high can the bottom of the tower be heated?