Dual Surfactant Digester Additive for Kraft Pulping
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Solution Overview
Problem
Current Kraft pulping processes face inefficiencies in reducing pulp rejects and enhancing pulp yield, with existing additives and methods failing to effectively minimize extractives and improve processing efficiency.
Innovation Solution
A dual surfactant system comprising an anionic surfactant and a polyoxyalkylene glycol or its derivative is employed in the cooking liquor medium, providing a synergistic effect that reduces extractives and improves pulp yield during the Kraft pulping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional single surfactant or no additive is used in Kraft pulping, then the process is simple, but extractives reduction and pulp yield enhancement are insufficient
Solution Approach 1:
The patent applies composite materials by combining two different surfactants (anionic surfactant and nonionic surfactant) into a dual-surfactant additive composition. This composite approach leverages the synergistic effects of both surfactant types to achieve superior extractives reduction and pulp yield enhancement compared to single surfactant systems, directly resolving the contradiction between productivity improvement and composition complexity.
Solution Approach 2:
The patent employs parameter changes by optimizing the concentration ratios and molecular weight characteristics of the dual surfactant system. By adjusting these parameters, the composition achieves maximum effectiveness in reducing extractives and enhancing pulp yield while maintaining practical complexity levels for industrial application.
2Object-affected harmful factors
If conventional additives are used, then the process is straightforward, but extractives reduction is insufficient
Solution Approach 1:
The dual-surfactant composite composition combines anionic and nonionic surfactants with complementary mechanisms for extractives removal. The anionic surfactant provides strong binding to lignin and extractives, while the nonionic surfactant enhances solubilization and emulsification, creating a synergistic system that achieves superior extractives reduction compared to conventional single additives.
Solution Approach 2:
The surfactant composition acts as an intermediary substance that mediates between the cooking liquor and extractives/lignin. The dual-surfactant system facilitates the removal of harmful extractives by forming intermediate complexes that enhance solubilization and separation, thereby reducing extractives content effectively.
3Productivity
If extended cooking time is used to improve pulp yield, then more pulp is produced, but processing time increases
Solution Approach 1:
The dual-surfactant additive composition performs preliminary action by pre-conditioning the wood chips before the main cooking process. The surfactants penetrate and swell the chip structure, pre-softening lignin and cellulose bonds, which accelerates the subsequent cooking process and enables higher pulp yield in reduced cooking time.
Solution Approach 2:
The patent employs parameter changes by modifying the chemical environment through surfactant addition, which alters the cooking kinetics. The dual-surfactant system changes the reaction parameters to favor faster lignin dissolution and fiber separation, thereby increasing pulp yield without extending cooking time.
4Object-affected harmful factors
If high surfactant concentration is used to maximize extractives reduction, then extractives are better removed, but cost and residue increase
Solution Approach 1:
The patent optimizes the concentration parameters of the dual-surfactant system to achieve maximum extractives removal efficiency at economical dosage levels. By carefully balancing the concentrations of anionic and nonionic surfactants, the composition achieves synergistic effects that maximize removal efficiency while minimizing surfactant quantity required and associated costs.
Solution Approach 2:
The composite dual-surfactant system enhances extractives removal efficiency per unit of surfactant consumed through synergistic interactions. The combination of anionic and nonionic surfactants creates a more effective removal mechanism that achieves better extractives reduction at lower overall concentrations compared to single surfactant systems, thereby reducing cost and residue.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The dual surfactant system significantly reduces extractives by up to 40% and enhances pulp yield by up to 15%, while also reducing pulp absorbency time, offering improved processing efficiency and cost savings over multiple plant runs.
Implementation Method 1
The composition comprises a first surfactant comprising an anionic surfactant and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof
Implementation Method 2
White liquor solubilizes the pulp and removes the lignin from the wood fibers
Implementation Method 3
The dual surfactant system significantly reduces extractives by up to 40%
Data Source
AI summary
In general, the present invention is directed to a method of cooking wood in a cooking liquor medium. The method comprises a step of providing wood to a treatment vessel and contacting the wood with a digester additive composition. The composition comprises a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof. Additionally, according to another embodiment, the present invention is directed to a digester additive composition comprising a first surfactant comprising an anionic surfactant, a derivative thereof, a salt thereof, or any combination thereof and a second surfactant comprising a polyoxyalkylene glycol or a derivative thereof.