Enhanced Dispersion and Stability of Petroleum Coke Water Slurries via Triblock Copolymer and Xanthan Gum: Rheological and Adsorption Studies

Abstract

The rheology of petroleum coke (petcoke) water slurries was investigated with a variety of nonionic and anionic dispersants including poly(ethylene oxide) (PEO)-b-poly(propylene oxide) (PPO)-b-PEO triblock copolymers (trade name: Pluronic, BASF), poly(vinyl alcohol) (PVA), polyvinylpyrrolidone (PVP), poly(ethylene oxide) (PEO), poly(carboxylate acid) (PCA), sodium lignosulfonate (SLS), and poly(acrylic acid) (PAA). Each effective dispersant system shared very similar rheological behavior to the others when examined at the same volume fraction from its maximum petcoke loading. Triblock copolymer, Pluronic F127 (F127), was found to be the best dispersant by comparing the maximum petcoke loading for each dispersant. The yield stress was measured as a function of petcoke loading and dispersant concentration for F127, and a minimum dispersant concentration was observed. An adsorption isotherm and atomic force microscopy (AFM) images reveal that this effective dispersion of petcoke particles by F127 is due to the formation of a uniform monolayer of brushes where hydrophobic PPO domains of F127 adhere to the petcoke surface, while hydrophilic PEO tails fill the gap between petcoke particles. F127 was then compared to other Pluronics with various PEO and PPO chain lengths, and the effects of surface and dispersant hydrophilicity were examined. Finally, xanthan gum (XG) was tested as a stabilizer in combination with F127 for potential industrial application, and F127 appears to break the XG aggregates into smaller aggregates through competitive adsorption, leading to an excellent degree of dispersion but the reduced stability of petcoke slurries.

Size-Controlled Preparation of Microsized Perfluorocarbon Emulsions as Oxygen Carriers via the Shirasu Porous Glass Membrane Emulsification Technique

“…Properties of Pluronics used in this study were summarized in Table . , Pluronics copolymers are the commercially available surfactant family that comprise a hydrophobic block of polypropylene oxide (PPO) flanked by two symmetric hydrophilic counterparts of polyethylene oxide (PEO). They are widely used as biological agents because of their biocompatibility and amphiphilicity. − During the formation of stable emulsions, the PPO blocks adsorb onto the hydrophobic surface with tailing PEO into the aqueous phase. In this work, their effects on emulsification of PFC using the SPG membrane were investigated for the first time.…”

Facile Production of Graphenic Microsheets and Their Assembly via Water-Based, Surfactant-Aided Mechanical Deformations

“…Then, Xanthan gum (0.54 g) is slowly added, and the stirring continued for 10 min. Pluronic F127 (0.6 g) is slowly added to the mixture, and the stirring continued for 10 min . The mixture solution is introduced into the gap between the two cylinders in a stationary TCR.…”

“…Pluronic F127 (0.6 g) is slowly added to the mixture, and the stirring continued for 10 min. 46 The mixture solution is introduced into the gap between the two cylinders in a stationary TCR. The rotation speed is fixed at 1500 rpm.…”

Prediction Method on the Static Stability of a Coal Water Mixture

“…Some traditional methods to evaluate the static stability of the CWM have been widely used at present, such as the Chinese standard method, cryosectioning method, , still standing observation method, , and rod penetration method, − which are subjective and not quantitative, require a long testing period, and can destroy the sample structure. Besides, with regard to the sample having good stability, it is also necessary to measure the static stability for at least 1 week to discriminate the small differences among samples.…”