Why Does Foam in Paper Manufacturing Keep Coming Back Breaking the Vicious Cycle of Ineffective Traditional Defoamers
In the papermaking process, foam is a persistent problem that is difficult to eliminate completely. It affects pulp flow, interferes with liquid level control, reduces dewatering efficiency, and causes pinholes and spots on the paper surface, or even paper breaks.
Many paper manufacturers adopt strikingly similar approaches to managing foam: when foam levels rise significantly, they increase the dosage of defoamer; when the effect wears off and conditions return to normal, they increase the dosage again. The result of this cycle is that the cost of defoamer per ton of paper rises year after year, yet foam-induced production fluctuations have not decreased—and new paper defects have even emerged. Industry research data indicates that the web breakage rate caused by foaming issues has risen by an average of 12% to 18%. This not only erodes companies’ profit margins but also leaves on-site operators scrambling to keep up.
This traditional "treating the symptoms rather than the cause" approach stems from a misunderstanding of the causes of foaming and the mechanism of action of defoamer. In fact, the properties of foam vary significantly across different sections of a paper mill. For example, in black liquor washing or pressure pulpers, ordinary silicone-based defoamers often fail due to demulsification in high-temperature, strongly alkaline environments. In such cases, specialized polyether-modified systems that are resistant to strong alkalis (pH up to 14) and high temperatures must be selected. In contrast, in white water recirculation systems, foam generation is primarily associated with mechanical shear and surfactants. New-generation fatty alcohol-based defoamers, with their excellent degassing performance and broad pH adaptability, can achieve long-lasting foam suppression without interfering with sizing or filler retention.
Simply increasing the dosage of conventional defoamers not only fails to resolve foaming issues under the complex operating conditions described above, but may also lead to adverse effects. Poor-quality or incompatible silicone-based products are highly prone to depositing on the wire or felt, which can in turn cause secondary paper defects such as poor sizing or reduced strength. Therefore, scientific foam control should not be a passive approach of “defoaming as soon as foam appears,” but rather a proactive strategy of “precision foam control.”
This is precisely the direction of industry transformation that RISE CHEMICAL is committed to driving. We believe that when selecting defoamers, one should not focus solely on unit price, but rather conduct a comprehensive evaluation of the defoamer’s compatibility under specific operating conditions, its long-lasting foam suppression capabilities, and the stability of its dosage per ton of paper. High-quality paper-making defoamers typically require rapid foam breaking within 30 seconds and long-lasting foam suppression for over 4 hours, while maintaining an extremely low COD contribution to meet environmental discharge standards.
As a professional defoamer chemical supplier, RISE CHEMICAL recommends that paper mills facing stubborn foaming issues prioritize partnering with technical experts capable of conducting water quality diagnostics and developing customized formulations. By systematically analyzing specific pulp types, machine speeds, and white water containment levels, we can tailor the most suitable solution for you, breaking the vicious cycle of “addition—failure—re-addition” at its source. This not only ensures paper quality but is also an essential step for paper manufacturers on the path to cost reduction, efficiency improvement, and green production.
