Study on the Preparation of Mesophase Pitch from Modified Naphthenic Vacuum Residue by Direct Thermal Treatment

Abstract

Two feedstocks (LPA and HPA) obtained from modification of naphthenic vacuum residues were selected to prepare mesophase pitch by direct thermal treatment. The influence of reaction temperature, soaking time, reaction pressure, and molecular structures of the feedstock on mesophase development was systematically investigated by analyzing variations in carbonization yield, carbon residue, quinoline insolubles (QI) content, density, optical textures, crystal structure, and surface morphology of derived products. It is found that the mesophase development and the properties of resultant mesophase products were closely related to the molecular structure of the original materials and preparation conditions. Compared with LPA, HPA was the preferable feedstock for thermal treatment because of its high degree of aromaticity and a large proportion of naphthenic carbon, and the resultant product obtained under the optimum conditions showed large flow domain mesophase, fewer alkyl side chains, and a high degree of molecular orientation.

Structural features of the oxidonitridophosphates K3 M III(PO3)3N (M III = Al, Ga)

“…Oxidonitridophosphates with general compositions M I 3 M III (PO 3 ) 3 N and M I 2 M II 2 (PO 3 ) 3 N (M I = Li, Na, K; M III = Al, Cr, Ga, V and Ti; M II = Mg, Fe) have been prepared by solid-state synthesis (Feldmann, 1987a,b;Massiot et al, 1996;Conanec et al, 1996), high-temperature thermal ammonolysis (Kim & Kim, 2013;Kim et al, 2017;Zhang et al, 2017), fluxgrowth (Zatovsky et al, 2006) or solid-solid ion-exchange (Liu et al, 2018). In recent years, oxidonitridophosphates containing the (PO 3 ) 3 N 6anion have been intensively studied as promising cathode materials for Na-ion and Li-ion batteries.…”

“…In recent years, oxidonitridophosphates containing the (PO 3 ) 3 N 6anion have been intensively studied as promising cathode materials for Na-ion and Li-ion batteries. In particular, ionic conductivities and redox properties were investigated in detail for Na 3 Ti(PO 3 ) 3 N (Liu et al, 2014), Na 3 V(PO 3 ) 3 N (Reynaud et al, 2017;Kim et al, 2017;Zhang et al, 2017;Xiao et al, 2021;Wang et al, 2021), Li 3 V(PO 3 ) 3 N (Liu et al, 2018), Na 2 Fe 2 (PO 3 ) 3 N and Li 2 Fe 2 (PO 3 ) 3 N (Liu et al, 2013), Na 2 Mg 2 (PO 3 ) 3 N (Cosby et al, 2020), and Li 2 Mg 2 (PO 3 ) 3 N (Liu et al, 2017). In addition, rareearth-doped Na 3 Al(PO 3 ) 3 N has been studied as a promising phosphor (Bang et al, 2013).…”

“…In addition, rareearth-doped Na 3 Al(PO 3 ) 3 N has been studied as a promising phosphor (Bang et al, 2013). However, the structural data for oxidonitridophosphates include only Na-or Li-containing compounds (Massiot et al, 1996;Zatovsky et al, 2006;Kim & Kim, 2013;Liu et al, 2013Liu et al, , 2017Liu et al, , 2018Zhang et al, 2017).…”

Effects of In-Process Hydrogenation on Mesophase Development during the Thermal Condensation of Petroleum Aromatic-Rich Fraction

“…As previously reported, the influences of molecular structures of feedstock on optical texture and rheological property of mesophase pitch have been studied widely. − The hydrogenation of raw materials or mesophase precursors was quite an effective method to improve the properties of mesophase pitch. − Menéndez et al have discussed the relationships between structure compositions of petroleum pitches and optical textures of cokes. The structural composition of pitches is proved to be the determining factor for the improvement of the optical textures of products.…”

Preparation and characterization of petroleum-based mesophase pitch by thermal condensation with in-process hydrogenation

“…The mesophase pitch was traditionally prepared by direct thermal condensation method [19][20][21] which had some advantages, such as simple process and operation. However, it had special requirement on feedstock's structure and equipment material.…”