Assessment of coke deposits on lamellar metal-modified MFI zeolites in ethylene transformation to aromatic liquids

Acidity modifications of nanozeolite-Y for enhanced selectivity to olefins from the steam catalytic cracking of dodecane

“… 8 Since the hydride transfer of nanozeolite is limited, the produced olefins may experience cyclization to aromatics, thus generating coke. 39 …”

“…8 Since the hydride transfer of nanozeolite is limited, the produced olens may experience cyclization to aromatics, thus generating coke. 39 The generated coke was investigated in this study via thermal gravimetric analysis (TGA). Coke as one of the inuencing factors in catalyst deactivation originates from the Paper catalyst or side reactions.…”

Enhanced CO2methanation at mild temperature on Ni/zeolite from kaolin: effect of metal–support interface

“…Light coke was consisted of the hydrogenated carbon species whereas heavy coke was often caused by the deposition of polycondensed aromatic or graphitic carbon. 51,52 The coke analyzed on Ni/NaY, Ni/NaA, and Ni/NaZSM-5 were characterized as hydrogenated carbon species based on the decomposition peak appeared at temperature below 500 °C. During CO 2 hydrogenation, coke was produced at high temperatures via Boudouard reaction ( eqn (6) ), 53 methane cracking/pyrolysis ( eqn (7) ), 54 and CO 2 or CO reduction ( eqn (8) and (9) ).…”

Progress of the Catalytic Deactivation of H‐ZSM‐5 Zeolite in Glycerol Dehydration

“…[65] There are two signals in the dTG curves corresponding to compounds with a lesser (H-rich coke, in a low-temperature region) or greater (H-deficient coke, in a high-temperature region) degree of aging. [66,67] The more hydrogenated compounds (Figure 4a) are formed in the first instants of the catalytic reaction. Over time, the deposits undergo chemical transformations, becoming more H-deficient (the proportion between the two types of coke increases over time, as shown in Figure 4a).…”

“…[68,69] Absorption in 410 nm is related to heavily methylated benzenium compounds and singly methylated bi and tricyclic species; anthra- cenic and phenanthrenic species absorbed in the 650 nm region. [67,70] Figure 4c compares the total weight percentage of coke and the intensity of the UV-Vis DRS signal in 410 nm, in relative intensity, throughout the reaction. The relative mass grows much faster than the DRS signal and stabilizes in the first few minutes of reaction.…”