What is the vapor pressure of oil and gas? How to adjust the vapor pressure of oil products?
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As the title suggests, how can the vapor pressure of oil products be controlled during production, and what are the factors that influence it?
The temperature required for the distillation of oil products is related to their vapor pressure; the lower the vapor pressure, the lower the temperature needed to distill the same oil products, and at the same temperature the dry point increases. The oil vapor partial pressure is the product of the operating pressure inside the equipment and the molecular fraction of the oil ； When the amounts of water vapor and inert gas in the tower remain constant, the oil-gas partial pressure decreases as the operating pressure in the tower drops. Therefore, provided the load in the tower permits, reducing the operating pressure in the tower or appropriately increasing the amount of steam fed into it can both lower the oil vapor pressure. As the processing volume increases, the operating pressure inside the tower inevitably rises, as does the vapor pressure of the oil and gas. If the temperatures at the top of the tower and along the various side streams are not adjusted, the quality of the product deteriorates.
The main factors affecting the partial pressure of oil and gas are pressure and temperature
I would like to ask: how does a change in the reflux at the top of a distillation column affect the vapor pressure of the product at the tower top, assuming that both temperature and pressure remain unchanged?
Changes in the steam flow rate affect the oil and gas partial pressures.
In catalytic units, changes in the amount of steam used for pre-raising the reaction mixture, the steam used for gas lift, the amount of inhibitor injected, and the amount of steam used for stirring in the distillation column have a significant impact on the vapor pressures of oil and gas in the distillation column; improper adjustment of these parameters can affect the yield of light oil.
Generally speaking, pressure should preferably not be used as an adjustable parameter; instead, the steam injection volume can be adjusted.
What is the effect of an increase in the top pressure and a decrease in temperature on the dry point of the product at the tower top?
There is no definite definition for this topic; when the flow rate returning to the tower increases, the corresponding temperature also decreases. You might say that this is impossible to achieve, but any change in flow rate will result in corresponding changes in the pressure and temperature at the top of the tower. As far as I understand it, the higher the pressure in a distillation tower, the lower the vapor pressure of the oil and gas. Hope this helps with your oil issue
The last edit to this post was made by You are me の Only on 2018-9-10 at 12:07. Raoult’s law: At a given temperature, the vapor pressure of a dilute solution of a poorly volatile non-electrolyte is equal to the saturated vapor pressure of the pure solvent multiplied by the mole fraction of the solvent； Dalton’s law: Assuming no chemical reactions occur between the components, the total pressure of an ideal gas mixture is equal to the sum of the partial pressures of each component ； When these two laws are combined, the molar fraction of the gas is equal to the saturated vapor pressure divided by the total pressure, multiplied by the molar fraction of the solution.
Taking the fractionation tower of a catalytic cracking unit as an example, when the pressure increases, the components become lighter or the proportion of light components rises. Without making any other adjustments – keeping the existing reflux and heat levels unchanged – the temperature at the top of the tower decreases; in other words, vaporization can no longer take place. At this point, the products at the top of the tower will definitely consist of lighter components, and the dry point of the crude gasoline will certainly decrease.