A concise review of current lignin production, applications, products and their environmental impact

• Published in: Industrial crops and products 2019-11, Vol.139, p.111526, Article 111526
• Main Authors: Bajwa, D.S., Pourhashem, G., Ullah, A.H., Bajwa, S.G.
• Format: Article
• Language: English
• Subjects: Life-cycle assessment; Lignin applications; Lignin production; Organosolv lignin; Techno-economic analysis
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2019.111526

•Bio-economy accelerating the development of high value lignin co-products.•Fuel, chemicals, and carbon rich materials are major lignin valorization products.•Techno-economic analysis of lignin derived products show reduced environmental impact.•Life cycle analysis critical to design of eco-friendly lignin valorization products. Lignin is the second most abundant natural material on the earth. Commercially, it is generated as a waste product from the paper and ethanol production. The worldwide production of lignin is approximately 100 million tonnes/year valued at USD 732.7 million in 2015. It is expected to reach $913.1 million by 2025 with compound annual growth rate (CAGR) of 2.2%. Two principal categories of lignin are ligno-sulphonate (˜88%) and kraft lignins (˜9%), however a new category organosolv (˜2%) is now gaining popularity due to the production of second generation biofuels (bioethanol production). The organosolv lignin segment is expected to experience the highest growth over the coming years, at an estimated CAGR of over 5% from 2016 to 2025. Chemically lignin is a polyaromatic macromolecule. The complexity and richness of its functional groups makes it attractive for converting into a variety of value added products like high performance carbon fiber, bio-oil, vanillin, and phenolic resin to name a few. Over the years lignin has been predominantly burnt as fuel for heat and power. Less than 2% of the available lignin was sold, primarily in the formulation of dispersants, adhesives and surfactants. However, in the last decade lignin-based research and new product development has picked significant momentum due to the bio-refinery concept as aging pulp and paper mills need to diversify their products portfolio to maintain their vitality. The emerging biofuel/bioenergy technologies are working to develop value-added co-products from lignin and bio-oil as a means of making the processes more cost effective. There is a resurgence in the demand for lignin for use in binders, adhesives, bioplastics, concrete admixtures and biomedical applications. Effective “upstream” and “downstream” valorization techniques are facilitating fine tuning of lignin as a building block for high value chemicals. Other market dynamics driving lignin use are stringent regulations for dust control, demand for high quality concrete admixtures and dispersants, and carbon rich products (activated carbon, carbon filer, resins etc.). To further accelerate development of ligni