A pilot-scale pulping facility has demonstrated the conversion of low-value agricultural and forestry residues into textile-grade dissolving pulp. The system breaks down biomass using controlled, lower-severity conditions that limit chemical waste and retain fibre integrity. The outcome establishes a practical route for converting widely discarded farm and forest materials into inputs for cellulose-based fibres such as rayon and lyocell.
- The process converts materials such as forest thinning debris, orchard trimmings and crop residues that are commonly burned or left to decay, contributing to air pollution and disposal challenges.
- Unlike conventional kraft pulping, the method avoids extreme temperatures, pressures and caustic chemicals, reducing energy use and eliminating toxic black liquor waste streams.
- Alongside dissolving pulp, the process produces purified lignin, fermentable sugar syrups and gypsum, enabling multiple usable outputs rather than a single waste byproduct.
- The pilot facility was built and operated by chemical engineering researchers at the University of California, Riverside, and housed at its Center for Environmental Research and Technology.
INSIDE THE PULPING METHOD: The pulping system separates cellulose from farm and forest biomass residues using controlled, lower-severity conditions that avoid the extreme heat, pressure and caustic chemistry typical of conventional mills. By breaking down biomass more gently, the process preserves cellulose quality required for textile-grade pulp while reducing overall energy demand. It also prevents the formation of toxic waste streams associated with traditional pulping, enabling cleaner material recovery.
- The system processes low-grade biomass such as forest thinning debris, orchard trimmings and crop residues that are widely available but difficult to dispose of responsibly.
- Operating under milder conditions allows cellulose fibres to be separated without damaging their structure, which is critical for producing dissolving pulp suitable for rayon and lyocell.
- Unlike kraft pulping, the process avoids generating black liquor, eliminating a major source of air and water pollution linked to conventional pulp mills.
- Lower energy use and reduced chemical severity make the process suitable for smaller-scale installations rather than large, centralised pulp factories.
MATERIALS GENERATED: The system delivers textile-grade dissolving pulp alongside several secondary outputs recovered during processing. By separating biomass components without generating hazardous waste, the process yields multiple usable materials from a single waste stream. This integrated output structure broadens potential applications across textiles and construction while maintaining a primary focus on cellulose-based fibre production.
- The dissolving pulp meets specifications required for cellulose-based textiles, including fibres such as rayon and lyocell used in performance sportswear and breathable undergarments.
- Purified lignin is recovered as a clean byproduct and can be used to manufacture biopolymer materials, including insulation and other construction products.
- Fermentable sugar syrups are produced during processing as a recovered output of the pulping system.
- Gypsum is also generated as a usable material identical to that used in drywall and other widely used building applications.
- Recovering multiple products reduces waste and improves overall material efficiency compared with conventional single-output pulping systems.
THE BROADER IMPACT: Converting agricultural and forestry waste into textile-grade pulp addresses persistent disposal and environmental challenges linked to burning or landfilling biomass residues. By enabling pulp production from materials that are already generated as waste, the process reduces pressure on virgin timber resources. Its ability to operate at smaller scales also supports more localised pulp production models.
- Waste streams such as forest thinning debris and orchard trimmings are often burned or left to decay, contributing to air pollution and wildfire risk.
- Using waste biomass for pulp production helps reduce reliance on clear-cut forestry traditionally associated with conventional pulp mills.
- The process operates with lower energy demand than kraft pulping, improving the environmental profile of cellulose-based textile fibres.
- Smaller, distributed installations could allow growers or forest managers to process waste near its source, with early commercial interest already exploring conversion of orchard waste into textile pulp.
- Localised pulp production may create new revenue streams from materials that are currently treated as disposal liabilities, following the suspension of over $1 million in federal grant funds originally designated to the project.
WHAT THEY SAID
It’s cleaner, milder, and uses less energy than traditional kraft pulping. It doesn’t compete with lumber because it can transform substandard wood waste into an on-spec high-value pulp product. With CELF, the process is so mild that it doesn’t break down the material in a destructive way, so harsh conditions are avoided, and the byproducts are usable, not hazardous.
— Charles Cai
Associate Research Professor
University of California, Riverside
