Hemp Cellulose Pulp Production via Alkali Cooking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for obtaining cellulosic pulp from hemp are inefficient, as they often require specific equipment and result in limited applications for hemp fibers, with hemp not being optimally utilized, leading to reduced income for farmers and degradation of the crop.
Innovation Solution
A process involving hemp stalks harvested at maturity, with a cooking and treatment step to remove lignins and hemicelluloses, producing a cellulose-rich pulp suitable for textile production using standard textile industry tools, including a cooking step at controlled temperatures and pressures, and refining to achieve high cellulose content and short fiber lengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hemp is harvested before seed maturity to produce textile fibers, then fiber quality is improved, but seed harvesting income is lost and fiber length becomes insufficient for modern textile tools
Solution Approach 1:
The hemp plant is segmented into different parts with different uses: seeds are harvested for income while stems are processed for cellulose pulp. The stem is further segmented into bark (for pulp) and shiv (for mulch or animal bedding), allowing multiple products from a single crop without compromising fiber quality or seed harvesting income.
Solution Approach 2:
The invention extracts and removes the shiv (inner core) from the stem before pulp production, concentrating the cellulose in the remaining bark portion. This extraction step increases cellulose content to over 80% while the removed shiv can be separately utilized for mulch or animal bedding, resolving the contradiction between fiber quality and overall productivity.
2Manufacturing precision
If traditional retting and scutching methods are used to separate fibers from shiv, then fiber separation is achieved, but specific equipment is required and fiber length is reduced to 50-80 cm
Solution Approach 1:
The invention replaces traditional mechanical retting and scutching equipment with a chemical cooking process using alkali solutions at controlled temperatures and pressures. This substitution eliminates the need for specialized mechanical equipment while achieving complete fiber-shiv separation and producing fibers suitable for modern textile tools.
Solution Approach 2:
The cooking process uses controlled parameters (temperature: 70-200°C, pressure: 5-20 bars, alkali concentration: 10-25%) to optimize fiber separation. By adjusting these parameters, the process achieves complete separation without requiring specialized equipment, and maintains fiber length suitable for modern textile manufacturing.
3Adaptability or versatility
If hemp fibers are shortened and mixed with cotton to enable spinning on standard tools, then compatibility with textile industry tools is improved, but hemp content is limited to 70% maximum
Solution Approach 1:
The cooking process adjusts parameters (temperature, pressure, cooking time, alkali concentration) to optimize fiber characteristics for compatibility with standard textile tools. By controlling these parameters, the process produces fibers that can be directly spun on standard cotton spinning tools while maintaining high hemp content (over 80%), eliminating the need to mix with cotton.
4Productivity
If the entire hemp plant is used after seed maturity, then overall utilization is improved, but the shiv degrades during retting and is limited to low-value mulch
Solution Approach 1:
The shiv is extracted and separated from the bark before cooking, allowing it to be processed separately. The extracted shiv can be used for high-value applications such as animal bedding or compost, while the bark is processed into high-value cellulose pulp for textile production, thereby increasing the overall value of hemp utilization.
Solution Approach 2:
The hemp plant is segmented into high-value components: seeds for income, bark for cellulose pulp, and shiv for animal bedding or compost. This segmentation allows each component to be optimized for its specific use, maximizing overall productivity and eliminating the low-value mulch limitation.
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 process enables the production of high-quality cellulose pulp with over 80% cellulose content, suitable for textile production, optimizing hemp utilization and reducing equipment requirements, thereby increasing the value of hemp crops and expanding their applications.
Implementation Method 1
the cooking step is carried out at a temperature of between 70 and 200°C
Implementation Method 2
the cooking and treatment steps prior to and/or subsequent to the cooking step are configured to remove at least a portion of the lignins and at least 20% by weight of the hemicelluloses
Implementation Method 3
the refining step is carried out at a temperature of between 30 and 220°C; the production process comprises a refining step, the fibers and/or pieces contained in the cellulose pulp having a length less than or equal to 10 mm at the end of this refining step
Data Source
AI summary
The invention relates to a method for obtaining a cellulosic pulp from a plant material comprising, by weight, at least 50% hemp stalks harvested at or after the flowering stage of maturity, the hemp stalks having at least 30% hemp chaff, a length less than 80 cm, and being subjected to at least one step of removing at least some of the lignins and at least 20% by weight of the hemicelluloses in order to obtain an amount of cellulose greater than 80% by weight. The invention also relates to a cellulosic pulp obtained using the method, the cellulosic pulp obtained comprising an amount of cellulose greater than 80% and a degree of polymerisation less than 1400, and a product obtained using this cellulosic pulp.