Pulp Defoamer: The “Foam Cleaner” and Key to Efficient Paper Production
In the paper industry, pulp processing foam control is known as the “foam cleaner,” playing a crucial role throughout the pulping process. From raw fiber cooking and bleaching to pulp washing and screening, foam generation remains a core challenge affecting production efficiency, product quality, and cost control. As a foreign trade factory specializing in defoamer research and production, we understand the significance of foam control for papermaking enterprises. This article analyzes the correlation between the pulping process and foam generation, the role of chemical additives, the mechanism of pulp defoamer, and key selection criteria. Additionally, we present real-world case studies demonstrating how scientific defoamer selection—such as our flagship product INVINO-6930—can achieve efficient and stable production.
Correlation Between the Pulping Process and Foam Generation
The pulping process is the core of the paper industry, and its complexity and diverse chemical reactions directly contribute to foam problems. The main pulping methods include chemical pulping, mechanical pulping, and semi-chemical pulping, each with unique foam formation mechanisms:
Chemical Pulping
Represented by the kraftprocess and sulfite process, chemical pulping decomposeslignin through high-temperature cooking (170-
180°C). In this process, strongalkaline chemicals such as NaOH and NazS react with fiberraw materials, releasing largeamounts of surface-activesubstances (e.g. ligninderivatives).Additionallystirring and steam injectionintroduce air, forming a viscousand stable foam layer. For instance, a large paper millusing the kraft process foundthat without a pulp defoamerfoam occupied 30% of thereactor’s effective volume reducing cooking efficiency by15%.
Mechanical Pulping
In mechanical pulping, wood is physically broken down using grindstones or refiners. The high-speed friction generates heat, prompting the release of natural surfactants such as resin acids and fatty acids. These substances, combined with air introduced by mechanical forces, create fine foam. A Nordic paper company‘s test data showed that foam-induced fiber loss in mechanical pulp production reached 8%, significantly impacting pulp yield.
Semi-Chemical Pulping
This method combines chemicalpretreatment with mechanicalrefining. Under mild chemicalconditions (such as the neutralsulfite process), raw materialsare partially softened, and theresulting fiber fragments tendto trap gas, forming foam. Thistype of foam has a smallparticle size and high stability,making it difficult for traditionaldefoamers to penetratequickly.
Chemical Additives in the Pulping Process and Their Synergistic Effects on Foam
Modern pulping processes use various chemicals not only to separate fibers and bleach pulp but also to influence foam stability:
- Cooking Aids: Anthraquinone (AQ) compounds accelerate delignification but produce amphiphilic oxidation products that enhance foam stability.
- Bleaching Agents: Oxidizers such as ClO₂ and H₂O₂ release CO₂ gas when breaking down residual lignin, forming a gas-liquid interface film with saponified substances in the pulp.
- Washing Agents: Surfactants (such as alkylbenzene sulfonates) improve washing efficiency but reduce surface tension, promoting foam formation.
Case Study: A Southeast Asian paper mill used H₂O₂ in its bleaching stage without a specialized pulp defoamer. The foam carried unreacted H₂O₂ into the wastewater system, leading to excessive COD levels and a 40% increase in wastewater treatment costs.
Core Functions and Technological Advancements of Pulp Defoamer
To meet the specific requirements of the pulping process, a high-performance pulp defoamer must fulfill three core functions:
- Rapid Foam Breakage: Quickly spreads across the foam film to reduce local surface tension.
- Long-Lasting Foam Suppression: Maintains stability under high-temperature and high-shear conditions.
- System Compatibility: Does not react negatively with pulping chemicals (such as strong alkalis and oxidizers) to avoid affecting pulp brightness or strength.
Our INVINO-6930 pulp defoamer demonstrates the following technological advantages:
- Molecular Design: Uses organosilicon-polyether block copolymers; siloxane segments provide low surface tension (≤22mN/m), while polyether segments enhance thermal stability (-10°C to 150°C).
- Particle Size Control: High-pressure homogenization controls active component particle sizes between 0.1-0.5μm, ensuring rapid diffusion in thick pulp.
- pH Adaptability: Modified hydrophobic particles remain stable in pH 2-14, preventing failure in acidic bleaching or alkaline cooking stages.
Pulp Defoamer-INVINO-6930 : An Innovative Solution for Pulp Defoaming
To address these challenges, INVINO-6930 offers four key innovations:
- Rapid Penetration Technology: Hyperbranched molecular structures enable three times faster spreading on foam films, with measured defoaming response time <15 seconds in mechanical pulp refining stages.
- Enhanced Thermal Stability: Nano-SiO₂ carriers ensure that active components maintain over 96% effectiveness in 130°C steam environments, preventing high-temperature degradation.
- Eco-Friendly Compliance: REACH-certified, free from APEO and heavy metals, with a biodegradation rate of ≥90%, meeting green papermaking requirements.
- Intelligent Dosing System: Our online foam monitoring and automatic dosing system dynamically adjusts dosage (recommended 0.01%-0.05%), reducing chemical consumption by 18% compared to fixed dosing methods.
Conclusion: Scientific Defoaming Drives Sustainable Paper Industry Development
As the paper industry moves toward high efficiency and low-carbon development, selecting a pulp defoamer is no longer just a cost consideration—it has become a comprehensive technical decision. By understanding the chemical essence of the pulping process and leveraging high-performance defoamers like INVINO-6930, companies can eliminate foam-related issues while achieving production efficiency and sustainability.
