by What is Crude Tall Oil?
Crude tall fuel (CTO) is a natural by-product of the kraft pulping process used in pulp mills to manufacture paper products. It is derived from the acid hydrolysis of lignin during the pulping process. CTO is a yellowish viscous liquid composed of fatty and resin acids, along with minor amounts of soap and volatile components.
Production and Composition
During the kraft pulping process, caustic soda and sodium sulfide are used to remove lignin from woodchips and create wood pulp. This separates the lignin from the cellulose fibers. The resulting “black liquor” contains lignin fragments along with spent cooking chemicals. When this black liquor undergoes acidification and evaporation, crude tall oil separates out as a hydrophobic layer. On average, 100 metric tons of wood yield approximately 1 metric ton of CTO.
CTO is composed primarily of fatty acids derived from plant cuticles and resins in wood. The three most abundant components are resin acids (45-65%), fatty acids like oleic and linoleic acids (15-40%), and small amounts of rosin acids. Other components include sterols, terpenes and terpenoids. The composition varies depending on the wood source, with softwoods yielding higher resin acid content versus hardwoods.
Applications and Uses
Due to its composition and low cost of production, Crude Tall Oil finds wide application in industries like adhesives, coatings, plastic additives, synthetic rubber manufacturing, cosmetics and more.
Some key uses are:
– Tall Oil Rosin – Resin acids in CTO can be isolated and purified as tall oil rosin, commonly used in rubber, adhesives and sealants.
– Soapstock – The fatty acid fraction is used to produce soapstock, mainly used in rubber processing as a softener and extender.
– Drilling Fluids – CTO derivatives acts as excellent lubricity and wetting agents in oil well drilling fluids.
– Biodiesel – Fatty acid methyl esters from CTO can be used to produce biodiesel fuel.
– Binders and Emulsifiers – CTO and its fractions act as binders, emulsifiers and dispersants in coatings, adhesives and other formulations.
– Surfactants – Specific oxidized CTO derivatives have applications as industrial surfactants and detergents.
Environmental Benefits
As CTO is a natural by-product of the pulping process with no additional consumption of fossil fuels or natural resources during production, it offers abundant environmental benefits over competing petroleum-based products. Some of the key environmental advantages include:
– Renewable Resource – CTO comes from renewable plant sources unlike petrochemicals extracted from finite fossil fuels.
– Reduces Landfilling – Utilizing CTO prevents waste generation and reduces landfilling of black liquor residues.
– Lowers Emissions – Replacing petrochemicals with CTO-based products lowers greenhouse gas emissions over product lifecycles.
– Biodegradable – crude tall oil derivatives are biodegradable and often replace non-renewable, toxic substances in formulations.
– Sustainable Industry – CTO supports the sustainable pulp industry and green carbon cycle of forests.
Research and New Applications
Continuous research aims to utilize CTO and its components more efficiently. New fractionation techniques help isolate high-purity individual components like tall oil rosins and fatty acids. Oxidized and functionalized derivatives expand the array of industrial uses. Emerging applications under study include biolubricants, bioplastics, biocomposites, resins for 3D printing, and more. With a wide range of beneficial properties, CTO is poised to replace many petro-based products and advance the bioeconomy.
CTO is a valuable bio-based resource from the pulp industry that provides multiple environmental and economic advantages compared to conventional fossil fuel-derived products. Ongoing research further opens new sustainable applications for this remarkable wood-derived by-product.
*Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it
