Modified Sulfuric Acid Delignification for Low-Energy Pulping
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Solution Overview
Problem
Current pulping processes, such as the kraft process, are energy-intensive and emit substantial odors and emissions, making them economically and environmentally undesirable, particularly when delignifying wood to produce pulp and biofuel.
Innovation Solution
An aqueous acidic composition comprising sulfuric acid, a modifying agent with an amine group, and peroxide is used to delignify biomass at room temperature, reducing energy and pressure requirements, and minimizing cellulose degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional kraft process is used for delignification, then lignin removal is achieved, but energy consumption and emissions increase substantially
Solution Approach 1:
The patent changes the chemical parameters of the pulping process by using modified sulfuric acid compositions with specific additives (such as sodium chlorate, sodium dichromate, or organic compounds) to achieve delignification under milder conditions. This allows the process to operate at lower temperatures and pressures compared to conventional kraft process, thereby reducing energy consumption and harmful emissions while maintaining effective lignin removal.
Solution Approach 2:
The invention employs composite chemical compositions that combine sulfuric acid with various modifying agents and additives. These composite solutions enhance the delignification capability while reducing the need for extreme process conditions, thus lowering energy consumption and environmental impact compared to traditional single-chemical systems.
2Productivity
If high temperature and pressure are applied in chemical pulping, then delignification efficiency improves, but energy consumption and equipment complexity increase
Solution Approach 1:
The patent modifies the chemical composition of the pulping agent to achieve delignification at lower temperatures and pressures. By incorporating specific additives like sodium chlorate, sodium dichromate, or organic compounds into the sulfuric acid system, the process achieves high delignification efficiency without requiring the extreme thermal and pressure conditions typical of conventional methods, thereby reducing energy consumption.
Solution Approach 2:
The modifying agents and additives act as intermediaries that facilitate the delignification reaction under milder conditions. These substances enhance the reactivity and selectivity of the pulping process, enabling efficient lignin removal at lower energy inputs while protecting cellulose fibers from degradation.
3Ease of operation
If mechanical treatment is used to separate fibers, then fiber separation is achieved, but fiber length and strength are reduced
Solution Approach 1:
The patent replaces mechanical fiber separation methods with a chemical pulping approach using modified sulfuric acid compositions. The chemical process selectively degrades lignin and hemicellulose, allowing fibers to separate naturally without intensive mechanical action. This substitution preserves fiber length and tensile strength while achieving effective fiber separation.
Solution Approach 2:
By changing the chemical parameters of the pulping system, the invention enables fiber separation to occur through chemical degradation of binding materials (lignin and hemicellulose) rather than mechanical force. This approach maintains fiber integrity and strength while achieving the desired fiber separation for paper production.
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 process achieves efficient delignification at lower temperatures and pressures, reducing energy consumption, emissions, and capital expenditures, while preserving cellulose integrity and avoiding membrane damage in water treatment applications.
Implementation Method 1
a modified mineral acid and a source of peroxide... exposing said plant material to said composition for a period of time sufficient to remove substantially all of the lignin present on said plant material
Data Source
AI summary
A one-pot process to separate lignin from a lignocellulosic feedstock, where the process involves the steps of: providing a vessel; providing the lignocellulosic feedstock; providing a composition that includes: an acid; a modifying agent including a compound containing an amine group; and a peroxide; exposing the lignocellulosic feedstock to the composition in the vessel for a period of time sufficient to remove at least 80% of the lignin present in the lignocellulosic feedstock; and, optionally, separating and removing a liquid phase that includes dissolved lignin fragments from a solid phase containing cellulose fibres.