Crystalline Behavior of Paraffin Wax

Abstract

Paraffin wax deposition has long been a vexing problem in industry. Especially, in offshore oil production, paraffin wax deposits and clogs pipes and containers because of low temperature, causing severe economic loss. It has been known that the crystallization of n-alkanes mainly causes the deposition of paraffin wax, which is necessary to understand the mechanism of the crystallization behavior of paraffin wax. We solve the challenge of describing the crystallization behavior of the alkane mixture system and evaluate the contributions of every carbon atom to crystallization based on the occupied volume, structure entropy, and order parameter. These results demonstrate that the middle atoms are the main contributor to crystallization, and the end atoms of n-alkanes are unfavorable for the crystallization of nalkanes, showing that increasing the number of end atoms, for example, adding branched alkanes, will hinder the crystallization of paraffin wax. Furthermore, perhydrosqualene is chosen to study the inhibition of crystallization by adding branched alkanes. As there are different properties between the end and the middle atoms, based on the principle of dissolution with similar properties, a small number of branched alkanes will promote crystallization. Also, an inhibitory effect of the end atoms is observed when the proportion of branched alkanes increases to a certain percentage. Our simulation work describes the crystallization behavior of paraffin wax in detail, providing theoretical assistance for preventing and controlling paraffin deposition.

Design of Crystal Growth Dimensionality in Synthetic Wax: The Kinetics of Nonisothermal Crystallization Processes

“…44,45 At this point, it should be stressed that the aggregation and dispersion of the amorphous state produce local fluctuations in density, significantly involved in the crystallization process. 43 The POM images display that crystallites of the Cr1 phase show mostly rodlike morphology and sporadically spheruliticlike forms at slow cooling. After crystallization of the longestchain molecules, the shorter molecules form networks with rod-and needle-shaped crystals of the Cr2 and Cr4 phases.…”

Molecular Dynamics Simulation of the Crystallization Behavior of Octadecane on a Homogeneous Nucleus

“…The unit cell angle α is 12% smaller than the literature value, β 9% and γ 1% smaller. At the end of the represented study, further works were published also reporting good results for the simulation of the crystal structure of alkanes with different force fields [24][25][26]. The united-atom TraPPE seems promising with some limitations in representing the crystals and phase change.…”

An anionic porphyrinylphosphonate-based hydrogen-bonded organic framework: optimization of proton conductivity through the exchange of counterions

“…58 It is well known that the interaction of porous coordination polymers with strong hydrogen bond-forming species, particularly with ammonia, leads to a significant improvement in the proton conductivity of these materials. [60][61][62][63] Thus, the application of such an approach resulted in the partial replacement of DMA of initial framework UPC-H5 by NH 4 + , leading to enhancement of proton conductivity to 1.59 × 10 −1 S cm −1 at 80 °C and 99% RH. 58 However, the mixed ligand strategy, using H 8 TPPP and phenylphosphonic acid, leads to the formation of 2D HOF GTUB5, which demonstrates the moderate proton conductivity of 3.0 × 10 −6 S cm −1 at 75 °C and 75% RH.…”