ABSTRACT The KS processing facility at the TLM oilfield employs Joule–Thomson (J‐T) throttling refrigeration in conjunction with low‐temperature separation and ethylene glycol circulation injection for the treatment of natural gas. Within 4 days of commissioning, the J‐T valve experienced a mechanical failure due to valve sticking. Subsequently, after 7 days of operation, an excessive pressure differential developed in the low‐temperature separator, resulting in diminished throughput and operational malfunction. Following adjustments to process parameters, equipment inspection, and comprehensive sampling analyses, factors such as inadequate glycol injection and mineral scales were excluded. The primary cause was determined to be the low solvent capacity of the relatively lean KS feed gas, which led to the precipitation of aromatic‐based wax (primarily biphenyl) under throttle‐cooling conditions. This study investigates the mechanism and mitigation of this severe aromatic wax blockage. Chemical characterization and thermodynamic analysis demonstrated that the depletion of C 5– C 8 light hydrocarbons in the feed gas significantly diminishes the solubility of polycyclic aromatic hydrocarbons (PAHs), consistent with the principle that a leaner gas phase exacerbates solute precipitation. Exploiting the capacity of light hydrocarbons to disrupt wax crystal lattices and increase the system's free volume, a circulating oil‐injection wax‐dissolution technology was developed. A predictive model was established using HYSYS software, complemented by field trials to optimize injection parameters. This novel technology effectively integrates light hydrocarbon circulation with wax mitigation, providing a high‐efficiency and cost‐effective solution for flow assurance in lean gas dehydration and hydrocarbon recovery units.
Wu et al. (Thu,) studied this question.