By Karl Seidel, Cablevey.com
Industrial hemp, also known as non-psychoactive hemp, refers to the Cannabis sativa plant that is grown specifically for industrial use, and it should not be confused with psychoactive marijuana.
Industrial hemp focuses on the use of the hemp plant material, which is composed of the stalk, seeds, and leaves of the plant and marketed as a seed, fiber, or dual-purpose crop. Because hemp is a versatile plant, there is a multitude of applications for hemp that range from clothing and beauty products to building materials and biofuel.
Other potential uses for hemp continue to be discovered and developed. For the industry to flourish, processing technology is essential to result in high value-added products. In this guide, we will discuss harvesting equipment, how hemp is processed, agricultural practices, the best equipment to process hemp, and how to maintain industry product quality standards.
The Best Processing Environments for Hemp Products
Hemp farming equipment can take a single acre of hemp to yield approximately 700 lbs of hemp grain or produce 5,300 lbs of straw on average. That same straw can be transformed into about 1,300 lbs of fiber.
For the industrial hemp farming cycle and cultivation process to go as expected and yield an optimal harvest, growing conditions on hemp farms must remain stable and free from pests and diseases. While hemp can grow in a wide variety of soils, it tends to thrive on nitrogen-rich land that is non-acidic; this type of land is also ideal for growing corn.
Therefore, soil tests to evaluate soil fertility and determine nutrient management are necessary for hemp cultivation. Hemp also prefers milder climatic conditions with a humid atmosphere. Hemp does, however, need at least 20-30 inches of rainfall during its growing cycle, and its demand for water increases until flowering begins.
But while adequate moisture is crucial when growing hemp, moisture retention during harvesting and processing are the enemy, and they can quickly reduce the quality of the crop. Because proper cleaning and drying are parts of processing, the processing environment should be stable.
The raw materials need to be protected from direct sunlight, extreme temperatures, and high levels of oxygen. To achieve this, hemp processing plants should be climate-controlled, adequately ventilated, and regulated for moisture. The processing equipment should be designed to limit exposure to the elements, which can introduce dust and other contaminants.
The Different Uses and Processing of Industrial Hemp
From the roots to the leaves, each component of the hemp plant can be processed and made into an industrial hemp product. Therefore, the harvesting and processing methods depend on the intended application.
The hemp stalk is one of the most versatile components of the plant. It can be used to make rope, paper, insulation, building materials, and animal bedding. The stalk’s bast fibers are used to make hemp textiles, and they can be blended with other fibers. CBD extracts also come from the plant’s stalks and stems through the process of CBD isolation.
The hemp flowers and buds can be used to extract seed oil. Hemp oil comes directly from the seeds in the hemp flowers. The hemp seeds on their own can be used in a variety of ways. Hemp seeds are touted as a superfood and can typically be found in health food stores today.
If a hemp product manufacturer only needs to harvest the hemp plant for its flowers and seeds, the remaining stalks and leaves will be regarded as waste. However, this hemp biomass can be used by another manufacturer to make fibers, cloths, or cords. The stalks can be fermented and turned into hemp ethanol or biofuel.
The processing equipment needed will depend on the end product. All the hemp plant’s components will go through cleaning and drying. Generally, the plant’s stalks will go through decortication and retting processes. Hemp flowers, buds, and leaves will go through bucking and de-hulling for the seeds. Bucking, also known as de-budding or destemming, refers to the process of removing the flower and leaves from the hemp plant’s stem.
Processing for the Hemp Plant’s Flowers and Seeds
Getting the timing right to harvest for seed production can be tricky because seeds mature at varying rates, with different seeds maturing at different times on the same plant. Sometimes, the lower seeds near the stalk will have already matured and split open, while the seeds at the top aren’t quite ready. The challenge of hemp harvesting is to do it when there is the least risk of losing seeds. Premature harvesting will only result in non-viable seeds.
Careful handling of the hemp seeds is crucial and requires the removal of the mature seeds from the flower heads. Because whole hemp seeds have hard outer shells, de-hulling hemp seeds is required to get them ready for the market. Historically, the de-hulling of seeds was done manually, making shelling hemp seeds a long and labor-intensive process.
Hemp farm equipment such as bucking machines, which also referred to as destemmers or debudders, speed up the industrial hemp production process. The flowering head of the plant is cut for seed processing while the stalks are sorted for fiber processing. While some hemp processors may take untrimmed material to process as is, others will use the material to produce other hemp-based products, such as oils or distillates.
Before storage, hemp seeds need to be properly cleaned and dried. To prevent damage, low-impact transfer mechanisms, such as conveyors, are used to transfer the seeds. Other types of machinery, such as augers that are run at high speeds, could potentially damage the seeds. Those traditional methods, which also include bucket elevators, tend to place more importance on speedy outputs than maintaining the material’s integrity.
Processing for the Hemp Plant’s Stalks
Harvesting for fiber production usually begins when plants are in early bloom. Historically, harvesting was done manually by hemp farmers to ensure the stalks would not be damaged. The core or the hurd is separated from the fiber by hand. Because of the fiber’s strength, pulling it from the stalks took a lot of manual force. Today, technology allows hemp crop harvesting and processing to be done by machines with equipment that is advanced enough to take care of the careful separation of the hemp fiber from the stalk.
There are two approaches to separating the hemp bast fiber from the woody core of the hemp called the hurd. This can be done mechanically through decortication or by the retting process. This bast fiber of the stalk is what is often turned into industrial products like rope, canvas, textiles, and clothing.
Retting refers to the process of separating the fiber from the rest of the plant, and it is crucial for ensuring the quality of the fiber produced. The quality can be quite complex as it requires breaking down the bark tissue that binds the fiber. Before hemp can be processed, the retted fiber must be dried to 10-15% moisture.
There are several retting methods, which include dew retting, water retting, warm water retting, green retting, and chemical retting. Dew retting can take up to five weeks, while water retting takes 7-10 days. Green retting uses an all-mechanical process to separate the fiber, and it is most often used in the production of textiles and paper. Of all the methods, chemical retting is the fastest as it dissolves the pectin in as little as 48 hours. This retting process is said to yield the highest quality product.
After decortication, the fiber is scutched and hackled. Scutching refers to the dressing of the hemp in preparation for spinning. The process separates the impurities from the raw material, such as seed particles and other matter. Scutching was once done by hand, but it is now done by a machine called a scutcher. Scutching hemp results in long fibers called lines. Hackling or combing removes the hurd particles and any broken fibers and helps align the fibers in a continuous sliver.
The Best Equipment to Process Hemp Fiber
During the bucking phase, the best destemming equipment will not pull or pop the delicate hemp flowers but rather, cuts them gently off the stem. When they are cut in this manner, there’s a minimal risk that the large crown buds will fall apart into small pieces. The goal is to keep the structure of the buds intact and fully preserved.
Because hemp decortication makes up the bulk of the hemp’s processing requirements for hemp fiber processing, hemp manufacturers need cutting-edge technology that streamlines the decortication process. A good decorticator system uses a reactor that passes hemp stalks through the machine to efficiently separate the hemp into pulp. Highly efficient decorticators can process tons of hemp per hour, and they are designed to process and decorticate hemp into a variety of different hemp products.
A modern decorticator separates the fiber from the rest of the stem and uses post-processing to remove the fiber’s resins and gums. A hammermill is used to separate the plant’s hurd from the bast fiber. The bast fiber is then cleaned, carded, refined, and cut to size. Once ready, the fibers can then be pressed tightly and prepared for baling. Processed bast fibers arrive at hemp product manufacturing facilities packaged in compressed bales similar to hay.
The hemp straw or stalk can also be used to make hemp pellets. To make hemp pellets, manufacturers use a pelletizer machine similar to the one used to make grass pellets. Hemp pellet mill systems should be paired with a suitable conveyance and transporting system to maintain the integrity and temperature of the hemp pellets.
The Best Equipment to Process Hemp Seeds
The de-hulling process for seed processing involves a hemp seed shelling machine that de-hulls and removes the outer shell. The equipment for hemp seed shelling consists of an input hopper, spiral elevator, and a de-hulling and separating unit. It also involves a device for back-flowing materials and collecting kernels. This gentle machine not only removes the seed’s crunchy skin but cleans it of hull residues. The kernels are separated from the seeds thanks to the equipment’s vibrating de-separator. After separation, the shells flow out and are discharged. Any back-flowing materials will be de-hulled and separated again.
For most hemp farmers, the preferred method for harvesting hemp for seed is straight combining. The combine header is positioned just high enough to cut the crop below the seed head, minimizing the amount of fiber that makes its way into the combine. When moving hemp seeds from the combine to the dryer, bin, cleaner or de-huller, and finally to the processor, the seeds need to be handled gently because they can easily become damaged. For this reason, seeding equipment, such as a gentle conveyor system, is crucial to ensuring the hemp seeds move from each phase of the processing safely. Hemp seeds are very delicate and burst easily. When this happens, they can become infested with germs or turn rancid.
To keep product blends at the correct ratios, the best type of equipment for conveying hemp is the tubular drag conveyor, often referred to as tubular and/or tubular drag cable & disc conveyors. Tubular drag conveyors are also best for processing hemp pellets and similar hemp products.
The problem with traditional equipment like screw augers, bucket elevators, pneumatic, belt conveyors, and vacuum conveyors is that they’re not ideal for maintaining consistency. When these conveyors have poor inlet designs or high conveyor speeds, materials may degrade, separate, or break. These methods are also susceptible to temperature changes, friction, and heat, which can threaten the integrity of the material.
Tubular drag conveyor systems can efficiently move many types of delicate materials, including hemp while keeping the plant parts like seed and fiber intact. The right tube systems will feature a modular design with a wide range of tube diameters and materials that can accommodate diverse applications.
Tubular drag conveyor technologies feature an innovative combination of conveyance tubes with cables and discs attached at set intervals that gently handle materials from an inlet within an enclosed tube.
Tubular drag conveyor systems feature stainless-steel tubes with either nylon or UHMW discs attached to a stainless-steel cable. Systems are moved by top-mounted drive units and pulled by sprockets that don’t touch or affect the materials being conveyed. Because of the machine’s slow-moving method of conveying, which runs about 100 feet per minute, materials are pulled from the infeed points to discharge ports as the cable and disc assembly passes through the tubing.
How to Maintain Quality in Hemp Processing
Ensuring the highest quality hemp products starts post-harvest during the drying phase. When hemp is dried quickly and cleaned, there is less risk of damage and loss of product. When hemp is not dried quickly enough, or it is harvested too wet, it can become contaminated with bacteria or fungi. Without adequate ventilation, the harvest may spoil, making it unsuitable for processing.
To yield the highest quality hemp seeds and fibers, gentle conveyance of materials is crucial. Cable conveyor and tubular drag conveyor systems are the gentle, clean, and cost-effective way to move materials around your hemp production facility.
To maintain quality, the processing environment should also be dust- and contamination-free. When choosing conveyance solutions, find tube conveyors that are designed to eliminate places where fine particles may accumulate. Discs should be solid and have no screws or bolts, and cables should be “jacketed” with nylon casings. Steel connectors should also be made of stainless steel. And for easy cleaning, all the equipment should be removable or able to be cleaned-in-place (CIP).
The enclosed tube keeps materials clean and safe while in transit, reduces waste, and keeps the hemp facility clean. It is also gentle enough to convey delicate hemp materials without breaking them. This smooth and gentle conveying system helps reduce waste by preventing degradation, material damage, and contamination.
Success in the industrial hemp industry depends on how efficiently and safely your hemp materials move around your production process facility, ultimately determining the difference between profit and loss. That’s why the right tube conveyor system for your hemp processing facility should be modularly designed and customized for your site, ensuring that all systems are optimized with component parts that are the right size, tube diameter, and material to suit your facility’s unique configuration, available space, and specific applications.