What is the principle of demulsification by hydrogenation demulsifying catalysts?
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What is the principle of demulsification by the demulsifying catalyst in the second hydrogenation and demulsification bed? Is diesel lighter after demulsification?
It’s cracking, I guess, to reduce diesel by 95 points. To make diesel lighter
In diesel hydrogenation, the main reactions include: hydrodesulfurization, denitration, deoxygenation, and demetallization； Olefin saturation, aromatic saturation ； The depressant reaction refers to a partial modification reaction in which macromolecules are converted into smaller molecules under certain reaction pressure and temperature; diesel upgrading units produce a small amount of naphtha, thereby reducing the specific gravity and freezing point of the product. Our company has a diesel hydroprocessing unit with a capacity of 600,000 tons per year; it is designed for a pressure of 12.7 MPa, while the actual operating pressure is generally maintained at around 10.0 MPa.
The wax component consists mainly of straight-chain hydrocarbons. The pores of the pour-point depressant catalyst are small enough to allow only straight-chain hydrocarbons to pass through, while naphthenes or aromatics cannot get through; as a result, only the straight-chain hydrocarbons undergo cracking in order to lower the pour point, and this also results in a loss of cetane number.
This post was last edited by TTILOOO on 2017-3-16 at 10:16. I mistook it for a antifreeze dispersant, so I deleted it
Hydrogen-assisted dewaxing is a typical shape-selective catalytic cracking reaction, and its reaction mechanism is similar to that of catalytic cracking; that is, the cracking reaction also takes place at proton acid sites, following a normal carbocation reaction mechanism； The difference is that the hydrogenation dew point depression catalyst is based on ZSM-5 zeolite, which consists of two intersecting pore systems: linear pores and zigzag pores. The linear pore opening is an ellipse with dimensions of 0.53 nm × 0.56 nm; due to the constraints imposed by the zeolite’s special pores, only paraffins with molecular diameters less than 0.55 nm, alkanes with short side chains, and cycloalkanes with long side chains – namely those components with high freezing points – can be selectively cracked into smaller molecules, thereby reducing the freezing point of the oil. The remaining large-molecule isoparaffins, cycloalkanes, and aromatics cannot enter these pores and therefore do not undergo any reaction. Only long and narrow paraffin molecules in diesel fractions can enter the micropores of zeolites for cracking; therefore, the hydrodesaturation process is also known as catalytic dewaxing process