The problem of viscosity reduction cracking
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I have a question for everyone: during visbreaking, what impact does the operating pressure have on the reaction? For example, in small laboratories, the exhaust gases are vented, which means that the reaction takes place at atmospheric pressure with no pressure at all; whereas in industrial settings there is a certain level of pressure. Does this change in pressure have a significant impact?
I also use a reactor in the laboratory to carry out viscosity-reducing cracking. I would like to ask what are the prerequisites for visbreaking? No charring, or is the amount of charring reaching a certain level? What is the difference between visbreaking and coking? Personally, I think the coking yield is definitely high, but the quality of the oil products might be poor. Thank you so much{:1_90:}
Reply to 2# dyzhh: Both viscosity reduction and coking are processes involved in the cracking of heavy oil. Viscosity reduction corresponds to mild cracking of heavy oil; it features a low conversion rate and a low coke formation rate. It is a process used to convert high-viscosity residual oil into low-viscosity residual oil. Its conversion rate depends on the reaction temperature and pressure. In existing processing technologies, viscosity reduction reactors are operated under pressure to extend the residence time of the feedstock in the reactor and thereby increase the conversion rate； Coking is a process that belongs to the category of deep cracking of heavy oil; it features high reaction temperatures, significant gas production, a high yield of light oil, and also a high yield of coke. It is widely used in current processes for the deep processing of heavy oil.
Reply to 3# liangming7810: If the experiment is carried out in a laboratory reactor, what requirements should be met regarding conditions such as temperature and pressure? In other words, to determine what criteria the product should meet, should we consider its viscosity, the amount of char formed, or something else? Thank you so much! !
Reply to 4# dyzhh: The reaction temperature is usually between 430 degrees and 440 degrees, with the pressure below 0.7 MPa. In our actual production, we check whether the viscosity of the residue meets the required standards
High operating pressure increases the degree of cracking and reduces the residence time
Theoretically, reaction pressure controls the depth of cracking, but in practice it is generally not used for this purpose.