Removal Of Catalyst Particles Research Articles

Microscopic mechanistic study on the removal of catalyst particles in FCCS by an electrostatic field

The catalyst solid particles in fluid catalytic cracking slurry (FCCS) can be removed by electrostatic separation. In this study, on the basis of the “effective contact point” model proposed by the authors for the nonuniform electric field (Li et al., 2019a [1]), the corresponding “effective contact point” model was proposed when the applied original electric field was uniform. Then, the adsorption properties of particles under the action of a uniform electric field and a nonuniform electric field were simulated and compared. The results showed that the “effective contact point” model in uniform electric field was correct, and the adsorption of the particles in the nonuniform electric field was better than that in the uniform electric field. The simulation of the electric field strength at the contact point of ellipsoidal fillers showed that the adsorption capacity of ellipsoidal fillers on particles was higher than that of the sphere fillers within a certain range.

Effect of structural parameters of an electrostatic separator on the removal of catalyst particles from fluid catalytic cracking slurry

The structural parameters of electrostatic separators used for the fluid catalytic cracking slurry (FCCS) are critical factors affecting the separation efficiency. This study investigated the influence of the filler diameter, stacking manner of fillers and inner electrode diameter on the separation efficiency. Simulation studies were carried out with experimental data considering change in the stacking manner of fillers and filler diameter; the filler diameters were 1.5 mm, 3 mm, and 5 mm, and four stacking manners were considered, namely face centered cubic (fcc), body centered cubic (bcc), simple cubic (sc), and hexagonal close packing (hcp). Experimental investigation was carried out by conducting tests in which the diameter of the inner electrode was varied from 8 mm to 16 mm. The results showed that with increase in the filler diameter, the separation efficiency decreased. The stacking manner of fcc corresponded to the highest separation efficiency. Further, the separation efficiency first decreased and later increased with increase in the inner electrode diameter. In addition, both the average electric field strength and nonuniformity coefficient influenced the separation efficiency. These findings could assist in the optimization of the structure of electrostatic separators and predict the separation effect.

Numerical and Experimental Study on the Removal of Catalyst Particles from Oil Slurry by Hydrocyclone

A new process of catalyst particles separations based on hydrocyclone technology is designed and an industrial sidetrack tester was set up in an 1.8 Mt/a catalytic cracking unit. In order to improve the separation efficiency of catalyst particles from oil slurry by hydrocyclones, the computational fluid dynamics method was used to optimize the geometry design of the hydrocyclone. Based on the simulation, a new design is proposed and proves to be able to improve the performance of hydrocyclone considerably. The catalyst solid particles concentrations in the range of 7,080–12,210 mg/L can be reduced to the range of 1,520–5,660 mg/L by the hydrocyclone. The method of hydrocyclone separation is feasible to remove catalyst particles from oil slurry.

Removal of Catalyst Particles from Oil Slurry by Hydrocyclone

Small diameter (10 mm) hydrocyclone is used for catalyst particles separations in this work. An industrial sidetrack tester was set up in 1.8 Mt/a catalytic cracking unit. When Reynolds number is invariable, the experimental results show that the pressure drop between the inlet and the overflow is not changed by changes in the split ratio. The effects of Reynolds number and split ratio on separation efficiency were studied. The removed efficiency of catalyst particle is more than 55% with Reynolds number of 850 ∼ 950.

Grafting of Poly(4-vinylpyridine) to Single-Walled Carbon Nanotubes and Assembly of Multilayer Films

Poly(4-vinylpyridine) grafts to single-walled carbon nanotubes (SWNT) during in situ free radical polymerization of 4-vinylpyridine. After removal of catalyst particles and unattached polymer by centrifugation and ultrafiltration, the SWNT−PVP contains about 63 wt % SWNT by TGA. SWNT−PVP solutions in DMF, methanol, and 2-propanol are stable for at least 8 months. Atomic force microscopy images show individual tubes. Raman spectra are consistent with debundled SWNT having PVP covalently attached. Near-infrared (NIR) spectra show band gap electronic transitions of SWNT. Layer by layer deposition of alternating thin films of SWNT−PVP and poly(acrylic acid) (PAA) adds a constant amount of SWNT−PVP in each bilayer. FTIR spectra of the films show hydrogen bonding between the PVP and the PAA.