The market for industrial hemp in 2019 reached $5 billion globally, according to a report by Brandessence Market Research. The market is expected to increase over sevenfold by 2026 to $36 billion worldwide. This is a compounded growth rate of 34 percent annually. Due to the astronomical growth of this market, makers of hemp products should look at ways to increase efficiency and production, including the introduction of customized hemp processing equipment.
Processing of Hemp Fiber, Oil & Seed
Hemp’s versatility and the recent reintroduction of the plant as a cash crop is driving the rapid growth in this sector. The increasing number of applications for which hemp fiber, oil, and seeds can be utilized makes it a particularly valuable commodity. Uses for industrial hemp include textiles, foods, beverages, pharmaceuticals, nutraceuticals, protein powders, building materials, animal bedding, and even personal care products.
Hemp Fiber Processing
The fibers on the outside of the hemp plant are what get processed. These hemp fibers can replace other fibers and resins, and their expanding use in manufacturing all sorts of products helps determine how hemp fibers are processed. Though the need for chemicals in hemp fiber processing is limited, it does involve several steps to deliver a viable product.
Steps for hemp fiber processing include:
- Retting uses moisture and microbes to break down hemp stalks by separating chemical bonds that hold the stems together. There are three general types of retting, though the latter two require a special facility.
These methods are:
- Field retting involves spreading harvested hemp in the fields for 4-6 weeks, where bacteria break down the outer layer, though this method produces poorer quality fibers.
- Water retting entails saturating dry hemp stalks in water steeped with bacteria to soften their outer layer, which produces higher-quality fibers; one subcategory of this hemp fiber processing method is known as double retting, which necessitates drying the stalks for a few months but results in very high-quality fibers.
- Chemical retting utilizes acids and distinct enzymes that break down the bast fibers, boiled in a mixture, often containing chemicals like hydrochloric acid, oxalic acid, sodium chloride, sodium hydroxide, and sodium sulfite; this method is quicker but more expensive.
- Decortication removes the hemp plant’s woody interior, separating these hemp fibers from the softer exterior fibers by passing it through fluted rollers. This breaks the hurd up into small pieces using a decorticator, a machine designed for this purpose. The remaining hurd is normally mechanically beaten, though less harsh modern techniques involve steam or ultrasonic breaking instead.
- Hackling involves combing the stalk to remove shorter and medium-sized hemp fibers. Special cutting machinery reduces fiber length while also removing and aligning wood particles.
- Spinning hemp requires first treating fibers by passing them through a container of hot water. Typically hemp fiber processing entails wet spinning, which further separates fibers by softening the pectin. Another method known as dry spinning is less expensive but results in coarser fibers.
- Bailing hemp fibers during processing eases transport and allows long-term storage. Larger, rounder bales dry better, as they are not as tightly packed as square bales. Bales should be stored in dry conditions, as excess dampness causes mold to develop, while twine or plastic net wrapping further protects it.
With tensile strength twice that of cotton, hemp fibers are useful for various consumer and industrial products.
Uses for Hemp Fiber
Hemp fiber processing results in strong, durable material often used to make fabrics or various types of cordage. As hemp fabric does not bleach easily, these fabrics often tend not to be dyed. However, certain hemp fiber processing methods result in a whitish, lustrous fabric similar to linen.
Products from hemp fiber include:
- Biodegradable and recyclable bioplastics.
- Blended fabrics with heightened antimicrobial and hypoallergenic properties as well as increased UV protection and durability.
- Building materials and insulation.
- Coarse fabrics like burlap and canvas.
- Cordage such as cable, rope, ship rigging, string, twine or yarn.
- Lightweight automotive parts.
- Paper with higher tear resistance.
- Shoes that are comfortable, sturdy and less expensive than leather.
- Synthetic sponges.
A composite material called “hempcrete” is used similarly to concrete for building applications that do not require load-bearing properties. Less expensive than wood, processed hemp fibers from the woody parts of the plant can be made into “hemp board,” a type of fiberboard. Hemp fibers are also used in place of fiberglass insulation in buildings. When it comes to hemp fiber, processing can even make hemp “waste” usable, such as pressing hemp dust or particles into pellets for fuel or to add nutrients to soil.
Hemp Oil Processing
To make hemp seed oil commercially, ripened hemp seeds are cold-pressed in much the same way as olive oil.
Hempseed oil production undergoes the following process:
- Deshell and remove seeds’ outer husk.
- Clean seeds to get rid of leaf matter, dirt, and other contamination.
- Load seed into hoppers that empty into successive cold expeller press heads.
- Extract oil through extrusion of seed into hemp cake, which separates solids from oil.
- Friction from pressing the seeds raises temperatures up to 104˚F (40˚C), which is mitigated by the cold heads.
- Fresh hemp seed oil drains through holes in the press cylinder, quickly cooling to 90˚F (32˚C) or cooler.
- When oil reaches holding reservoir, temperatures drop below 68˚F (20˚C)
- Fresh hemp seed oil passes through a stainless-steel filter, which removes suspended solids.
- This oil then drains into a storage reservoir.
- In the reservoir, nitrogen gas is flushed through the oil, removing suspended oxygen molecules.
- Hemp Seed oil is then packaged in bottles, drums, jugs, pails or other containers in an oxygen-free environment.
Another hemp oil type is made from the plant’s flowers, leaves, and stalks, called CBD oil, as it contains the therapeutic compound cannabidiol, abbreviated as CBD. This oil can either be ingested or used topically.
CBD oil is normally extracted through one of these techniques:
- Ethanol extraction involves soaking plants in grain alcohol to release cannabinoids.
- Carbon dioxide extraction uses this gas in a condensed, super-cooled form to isolate cannabinoids without leaving any contaminants or chemicals; it requires more equipment but results in a more potent and safer end product.
- Oil extraction cooks and heats the plant in a carrier oil to release the required cannabinoids.
Hemp Seed oil can be used as a carrier oil with the oil extraction method.
Uses for Hemp Oils
A number of health benefits come from amino acids, essential fatty acids, minerals, and vitamins in hemp oils, which can be taken orally or applied topically. Hemp oils can be used for:
- Considerably decreasing total and “bad” cholesterol levels, reducing risk of heart disease, high blood pressure, and stroke.
- Inhibiting bacterial growth.
- Lowering blood pressure for those with hypertension.
- Reducing emotional and physical symptoms of PMS (premenstrual syndrome).
- Relieving symptoms from inflammatory conditions, including irritable bowel syndrome, multiple sclerosis, and rheumatoid arthritis.
- Strengthening skin to resist infections.
- Treating skin conditions like acne, eczema, and psoriasis.
Hemp Seed oil can be mixed into salad dressings or in other foods and consumed on its own or in place of olive or other cooking oil.
Hemp Seed Processing
Only female plants produce seeds, while also working best for hemp oil and hemp fiber processing, as they contain more oils and fibers than male plants. However, to produce the seeds needed for hemp seed oil, or to produce seeds for other purposes, requires that male plants be scattered amidst the hemp crop. Without their pollen, hemp flowers will remain seedless.
Recovering hemp seed from plants is a relatively simple process involving techniques that include mechanical sieving, classifying, and gravity separation. Each of these methods can be used separately or in conjunction with one another. When produced for food, seeds also undergo a dehulling process to separate their outer husks and oils.
Separating seeds involves first threshing them, which removes and separates hemp seeds from husks. Most mechanical threshers can handle whole plants or smaller hemp flowers filled with seed. This material then passes through multiple sieves to remove dust and debris. In some cases, a hemp seed grader separates seeds by size, allocating different sizes according to application. For certain applications, air classification may also be appropriate.
Uses for Hemp Seed
Hemp seeds are valuable in their own right, not just for hemp seed oil, and can be eaten on their own as food. The balance of solids after extracting hemp seed oil is hemp cake, from which other products like flours or powders are made. Some research has even looked at it as a meat additive or meat protein substitute.
Applications for hemp seeds include:
- Animal feed
- Dietary supplements
- For future hemp crops
- Hemp butter made from whole hemp seeds
- Hemp flour made from hemp cake
- Hemp protein powder made from hemp cake
- Traditionally used in bird seed
Hemp seeds are very nutritious in their own right. They contain amino acids, including nine types that the body cannot produce. A third protein makes hemp seeds a complete source of this nutrient used for muscle and tissue repair and health. They also have ample amounts of omega 3 and 6; both are considered good fats and iron, magnesium, phosphorus, vitamin A, vitamin E, and zinc.
Hemp Processing Equipment by Prater Industries
Prater Industries manufactures a wide variety of hemp processing equipment customized to fit specific applications and customer needs. These include various deck screeners, lump breakers, hammermills, airlock valves, and feeders.
Brief descriptions of Prater hemp processing equipment:
- Vibratory deck screeners are used for removing stalks, separating hemp particles and excess liquid from wet plant material, along with removing finely ground hemp dust, oversized particles, and foreign substances from the production line.
- Lump breakers are utilized to break apart agglomerated or densified plant matter, such as compacted hemp bales, prior to hemp oil extraction, reducing plant matter into smaller particles and improving the flow of hemp along the production line.
- Hammermills work well for high-capacity production lines, offering an efficient means for grinding hemp down into uniform particle size distributions prior to extracting oils; these mills also feature a full-screen design that enhances the quality of the end product, extends equipment lifecycles, and increases throughput.
- Prater’s blow-through airlock models are designed to facilitate pneumatic conveyancing of hemp along the production line, with capabilities that allow it to be used in existing rotary valves that have been retrofitted and for low applications with low headroom.
- Air Classifying Mills are used to grind defatted hemp protein meal into flour.
Prater also manufactures a variety of mills, air classifiers, rotary airlocks, fine grinders, and other hemp processing equipment customized to meet certain criteria and work readily in multiple applications.