skim line
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The bottoms of the three desulfurization towers used in diesel hydrogenation (cyclic hydrogen desulfurization tower, light gas desulfurization tower, and dry gas desulfurization tower) are all equipped with oil skimming lines. What is their function? It’s because there is still a small amount of oil in the desulfurization tower (caused by sulfur-containing gases? ? ）
It is because of the cyclic hydrogen; during the separation of dry gas, light hydrocarbons may end up in the desulfurization tower, causing the lean liquid to foam. Since oil has a lower density than the lean liquid, light oil will appear on the surface of the lean liquid. Regular oil skimming can prevent foaming of the lean liquid and avoid a decline in the desulfurization efficiency
Thank you for your prompt reply; I am very grateful. In other words, the oil is formed by the condensation of light hydrocarbons; therefore, the temperature difference between the lean solvent and the recycled hydrogen is greater than 5°C? Regarding the foaming phenomenon, are there any other substances besides light hydrocarbons that can cause foaming? On the MDEA solvent regeneration flow diagram, there is a device for filtering the lean liquid in order to remove thermally stable salts. How are these stable salts formed?
That low-temperature dehydrogenation unit in front of the dry gas desulfurization tower is also designed to prevent foaming of the solvent inside the tower, right?
It is correct to keep the control ratio of circulating hydrogen higher than that of the lean liquid. There are many reasons for foaming: excessive gas-phase impurities, inadequate purging of pipelines, presence of coke powder, high temperatures, etc. Regarding heat-stable salts, they are formed as a result of reactions with oxygen, as well as through the continuous accumulation of impurities such as organic acids in the medium!
Yes, it can easily cause foaming of the amine solution, resulting in a reduced desulfurization efficiency. If there is a high content of light hydrocarbons, it can lead to an imbalance between gas and liquid in the tower, potentially causing tower flooding accidents
The desulfurization tower must be equipped with an oil skimming line; if there is still oil in the gas, it will cause the amine solution to foam, affecting operations and leading to unstable liquid level and pressure
A difference of 5 degrees isn’t meant to be interpreted in that way; it’s mainly because low temperatures facilitate absorption, while high temperatures facilitate decomposition
Are your swirl hydrocarbon removal tanks cylindrical? No structural diagram was sent for me to take a look at!
I just started working; I haven’t entered the facility yet. . Learn by looking at pictures