Advancing Foam Control in Paper Machines with Ziegler-Derived Linear Saturated Fatty Alcohol Emulsions

Foam and entrained air impede pulp and paper operations, particularly in modern high-speed and closed-loop systems. Fatty alcohol-based defoamers remain cost-effective and robust under elevated temperature and shear. This study evaluates a distinct class of long-chain fatty alcohols produced by blending narrowly distributed fatty alcohol fractions with synthetic Ziegler-derived linear saturated alcohols. The blend was designed to increase the melting point, broaden the alkyl chain-length distribution, and enhance the relative contributions of both short- and long-chain fatty alcohol fractions, resulting in a refined C18–C22 distribution, a higher hydroxyl value, and an elevated melting point compared to conventional Ziegler-derived alcohols. Methods: The performance was assessed in oil-in-water (O/W) emulsification and foam control under white-water conditions (35–60 °C). Emulsions prepared at controlled shear rates showed stable viscosity and structural integrity under standard, thermal, and shear-induced storage conditions, whereas formulations containing lower-melting fatty alcohols often demonstrated phase separation and thickening at a high active content. A volumetric method was developed to quantify antifoam action by measuring the maximum foam expansion length (tmax). Antifoaming and defoaming behavior were measured using an Automated Dynamic Foam Analyzer (DFA) at varying temperatures and a 30 ppm active dosage. In-process trials evaluated midstage addition under representative mill conditions. Results and Findings: DFA measurements demonstrated that 30 ppm of active dosage significantly reduced both foam formation rate and foam half-life across all temperatures. The optimized fatty alcohol blend exhibited strong defoaming below its melting point (∼55 °C), attributed to the enhanced entering and bridging of foam lamellae by well-dispersed alcohol particles. Particles within the 3–6 μm range generated sufficient capillary pressure and favorable spreading to promote bridging-dewetting and rapid film rupture. At 55–60 °C, defoaming peaked near 55 °C, and both high-melting emulsions performed similarly at 60 °C. In-process trials showed that midstage addition of 30 ppm emulsion led to near-complete foam collapse. Overall, the tailored long-chain fatty alcohol blend provides a reliable and efficient foam-control agent for pulp and paper applications, offering superior stability and performance relative to those of traditional fatty alcohol formulations.