The Hemp Fiber Industry

YouTube video about production of hemp fiber

Notes

when
- fiber crop: late summer, just before flowering
  - still green
  - lower lignin in fiber
    - plant glue
    - makes stalks more rigid
    - less cellulose as percentage of bark
    - removed during degumming
- grain crops
  - late fall, after seeds mature
  - stalks brown and dry
  - higher lignin
  - not as valuable
machinery
- Sickle Bar
  - convenient
  - cut at base
  - pulled by tractor
  - left in field for retting
retting
- retting = rotting
- bacteria and moisture to remove tissues and pectins around bast fiber bundles
- partially decompose
- easier to separate hurd during cortication
- methods
  - field retting
    - stalks spread on field in thin layers
    - water from moisture in air
    - risk of over- or under-retting
    - may need to turn over for uniformity
    - too warm and dry, may dry out the stalks
    - prolonged rain can decompose completely
  - water retting
    - underwater
    - natural lake or stream, or tank
    - faster and more precise
    - takes more time and effort to move
rake machine
- straighten and narrow rows of stalks
- lines up stalks for baling
baling machine
- convenient moving
- square or round
  - square more efficient for transport
  - round hold more weight, prevent fiber tangling
  - decortication machinery can favor one or the other
- may become a commodity

shown: modified cotton gin
Decortication
- separate bark from core
- usually by crushing with hammer mill, specialized machinery, or modified cotton gin
- scutching machine with rollers or blades
- different machines produce different fiber lengths
- products
  - Dirty Bast Fiber
  - Dirty Hurd Fiber
Cleaning
- shaking tables, screens, and air jets
- more purity, more value
- Clean Bast Fiber
- Clean Hurd Fiber
- won’t be commodities
- not uniform in length
Cutting/Reduction
- target fiber lengths
- long: insulation
- medium: composite
- short: papers, plastics
- finer hurd: engineered wood
- micronized hurd: plastics
- sold by decortication facilities
plant capacity in tons per hour
Delignification
- clean bast fiber in
- remove lignin
- ribbons of fiber bundles
- thinner fibers for finer yarns
- finer, whiter, fluffier
- closer to cotton fibers
Combing
- align the fibers
- separates long (line) bast fibers from short (toe) fibers
Spinning
- long hemp fibers
- on equipment designed for flax
- fibers usually 4-6 inches long
- 100% hemp yarn
Carding
- shorter hemp fibers
- usually blended with cotton
- varying percentage mixes
- similar to brushing
- disentangles, cleans, intermixes
- “sliver” (continuous web)
- then spun
  - cotton machinery
  - 3/4 to 1-1/2 inch fibers
facilities usually flax or cotton spinning systems
short degummed hemp fiber can become a commodity
closes to standard cotton bale

grain crops
- stalks are secondary product
- average yield for grain 800 pounds per acre
- selling for 55-65 cents per pound
- $440-520 per acre
- hemp stray about 2k pounds
- at 0.10 per, $200 more per acre
- $640-720 per acre combined
Fiber Crop
- average 8,000 pounds per acre
- 0.10 per pound for straw
- $800 per acre
Industrial Market
- assuming no loss
- clean bast $1.30 per pound
- clean hurd $0.45 per pound
- prices too low to motivate
- same time, bast fiber too expensive to compete with other bast fibers
- cost of hurd too expensive for building or animal bedding
lower cost of processing?
- economies of scale
- larger plants are being built
- tens of millions to build
- lowers industrial price
- price reduction of 25% would still make more expensive than competing fibers