Researchers in Bio4Energy have published a review article designed to guide biorefinery industry looking to make value-added products from side streams of pulp and paper production such as crude tall oil from trees. This is an area that is attracting the attention of several industrial operators in the vanguard of trying to make renewable chemicals with properties similar to chemicals refined from fossil oil.
Just as the Nordic Paper Journal noted in a recent article, there is likely to be big money to make from side streams of the pulping process. The Bio4Energy researchers point to several routes by which substantially value-added fragrances, pharmaceuticals, bio-based plastics, renewable diesel, specialty chemicals or even jet fuel may be made.
'Industry has realised it can increase the profitability of its operations by making use of the terpene fractions…. Our article gives them a tool for identifying what routes to go down', said Jyri-Pekka Mikkola, professor at Umeå University in Sweden and an expert on catalysis and separation of wood products in Bio4Energy.
The Bio4Energy researchers' 29-page review article gives a complete overview of the latest research on various compounds extracted from turpentine—produced worldwide in approximately 35,000 tonnes each year as a side stream in chemical or mechanical pulping of wood—and treated by heterogeneous catalysis. The article appeared in the April 2015 issue of the Chemical Reviews which receives even more citations by other researchers than the prestigious scientific journals Nature or Science.
While many of us would know turpentine as a clear liquid with a distinct smell, used to clean paint brushes after having painted a fence or made an oil painting, in this context it is a collective term used to describe a mixture containing a number of monoterpene isomers, such as α-pinene, β-pinene, 3-carene and camphene.
'Today these substances are not being optimised and approximately half the monoterpenes go to combustion [because] separation has not been a priority. The part which is being recovered is burnt or distilled and turned into marketable products. A small share goes to the perfumery industry. Bulk chemicals, glue and biodiesel are other examples [of end products]. But what we are saying is that one can make even more expensive stuff', according to Mikkola.
'If we succeed in making molecules, for instance, they could be put to use in the pharmaceutical industry, bio-based plastics or specialty chemicals. We have here a significant resource that we need to make better use of'.
What about cost efficiency: Would these chemicals be competitive with similar ones based on petrochemicals?
'With the current[ly low] oil price this is not possible. Political support measures are needed', Mikkola acknowledged.
His comments echo a recent report by a Forest Chemistry project in which Bio4Energy researchers assisted Sweden-based chemical and forestry industry to assess the feasibility of replacing 25 per cent of the petrochemical feedstock used by plastic makers at Stenungssund on the Swedish west coast. The report authors argue that so-called 'green' chemicals could be produced cost-effectively by that industry cluster, if similar government incentives were given to chemical making as those in place for (some types of) biofuel production.
The Bio4Energy researchers behind the review article Catalytic Upgrading of Extractives to Chemicals: Monoterpenes to 'EXICALS', all work at Umeå University and/or the Åbo Akademi University in Finland. They include the postdoctoral researcher Mikhail Golets (leading author), senior research engineer Ajaikumar Samikannu and professor Mikkola.