When crude oil is extracted out of a subterranean reservoir at high temperature and pressure, it is usually transported via a pipeline, where the crude oil experiences radical changes in its physical and chemical properties, instigating numerous complications. Among the various flow assurance problems, wax deposition and build up are among the most commonly found. However, the accurate mechanism of wax deposition is still unclear and is widely debated among researchers. The mechanism under multiphase conditions is also an ambiguity. This review covers the six wax deposition mechanisms, the challenges in multiphase flow conditions, the latest types of chemical inhibitor, and a summary of factors governing chemical inhibitor performance.

The preparation of soluble microporous polymers for large-scale gas storage and separation with low cost, scalability and synthetic diversification is extremely challenging. Here, we report the synthesis of solution-processable hypercrosslinked polymers (SHCPs) by folding polystyrene molecules at high dilution. A low cost knitting method is employed and by slowly adding an external crosslinker, intramolecular cross-links were introduced. Despite being highly cross-linked, the resulting hypercrosslinked polymers dissolve in a range of organic solvents to form thermodynamically stable homogenous liquids. By increasing the concentration of polystyrene and the amount of crosslinker, the BET surface area of SHCPs increased with the largest surface area of 724 m² g⁻¹. Moreover, they also show comparable gas uptake properties reaching 8.11 wt% CO₂ adsorption (1.13 bar and 273 K), 1.01 wt% H₂ adsorption (1.13 bar and 77 K), and 0.14 wt% CH₄ adsorption (1.13 bar and 273 K). The reaction offers a route to new classes of solution-processable microporous polymers as promising materials for gas storage and separation.

A new class of CO₂ sorbents, namely polyethylenimine hydrogel beads (PEI HBs), has been developed via a simple one-step crosslinking reaction of PEI using epichlorohydrin (EPC).