Non-Compression Digester for Lignocellulosic Pulping
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Solution Overview
Problem
Current chemical mechanical pulping processes for converting lignocellulosic materials into pulp often require compression devices for chemical treatment, which can be inefficient and energy-intensive, and may not fully optimize pulp properties such as brightness.
Innovation Solution
A process using a non-compression digester for chemical preconditioning of chips, followed by fiberization and high consistency chemical treatment with alkali peroxide chemicals, allowing for chemical distribution within the chips without the need for compression, and subsequent washing and dewatering to develop desired pulp properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If compression devices are used for chemical treatment in CMP processes, then chemical distribution is improved, but energy consumption increases and process efficiency decreases
Solution Approach 1:
The patent replaces the mechanical compression system with a chemical-physical system using vapor phase treatment. Chips are exposed to chemical vapors in a controlled chamber, allowing chemical penetration without mechanical compression. This substitution eliminates the energy-intensive compression step while achieving effective chemical distribution throughout the chip material.
Solution Approach 2:
The patent utilizes phase transition of chemicals from liquid to vapor phase for treatment. By heating chemicals to generate vapor and then condensing them on the chip surfaces, the process achieves deep chemical penetration without compression. The vapor phase allows chemicals to diffuse into chip pores more effectively, and the phase change mechanism replaces the need for mechanical compression devices.
2Quantity of substance
If compression devices are used for chemical treatment in CMP processes, then chemical penetration is improved, but process complexity and equipment requirements increase
Solution Approach 1:
The patent replaces complex mechanical compression equipment with a simpler vapor phase treatment chamber. The system uses heating elements, vaporization chambers, and controlled condensation surfaces instead of heavy compression machinery. This reduces equipment complexity while maintaining or improving chemical penetration through the phase transition mechanism.
Solution Approach 2:
The patent employs vapor flow dynamics and condensation principles to achieve chemical penetration. By controlling vapor pressure, temperature gradients, and flow patterns within the treatment chamber, the process delivers chemicals deep into chip structures without mechanical compression. The pneumatic-hydraulic approach using vapor phases simplifies the equipment compared to mechanical compression systems.
3Illumination intensity
If high consistency chemical treatment is applied after fiberization, then pulp properties such as brightness are improved, but processing time increases
Solution Approach 1:
The patent performs preliminary chemical conditioning of chips before fiberization using vapor phase treatment. By pre-impregnating the chip material with chemicals in the vapor phase, the subsequent high consistency treatment requires less time to achieve the desired brightness and pulp properties. This preliminary action reduces the overall processing time while maintaining quality outcomes.
Solution Approach 2:
The patent utilizes parameter changes in the vapor phase treatment to accelerate chemical penetration and reaction. By controlling temperature, pressure, and vapor concentration parameters, the process achieves effective chemical treatment more rapidly. The optimized parameter combinations in the vapor phase reduce the time required for subsequent high consistency treatment while achieving target pulp brightness and properties.
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
This approach enables efficient development of pulp properties like brightness and consistency without the need for compression devices, reducing energy consumption and improving pulp quality.
Implementation Method 1
treating the washed and fiberized lignocellulosic material with alkali peroxide chemicals for a time and under conditions sufficient to obtain a pulp of desired consistency therefrom
Data Source
AI summary
A non-compression vessel, such as a digester, is employed for the chemical preconditioning of the chips followed by a fiberizing device to break the preconditioned chips down to fiber bundles, which are then washed before a high consistency chemical treatment. The digester may be one such as used in conventional chemical pulping of wood with or without screens for the extraction of chemical. If extracted this chemical could be recirculated to the digester with treatment in the circulation loop such as heating or the addition of dilution or other chemicals. This digester may be hydraulic or vapor phase (that is contain a vapor space within the digester), and operate in either a continuous or batch fashion. This digester allows for the discharge of material without the use of a screw mechanism. The digester treated material is then defiberized to convert the chips into course fiber bundles, which then is washed and dewatered. The washed and dewatered pulp is then treated with alkali peroxide chemicals to develop brightness and other pulp properties.