A new report designed to lay bare the potential for coupling pulp production with biofuel making from pulping residue, shows that there is a double benefit to be had in doing so for pulp mill operators.
First, production capacity could be increased at existing mills. Second, climate-efficient transport biofuel could be produced at a cost per energy unit that is on a par or better, compared with similar biofuels made from residues from forestry operations.
The new fuels would be so-called drop-in biofuels, which means that they are functional equivalents of their petroleum fuel counterparts and thus can be directly blended in with these latter at any ratio.
The researchers' report identifies two main technologies that would put the production cost of the biofuel at 80 euros per megawatt-hour (MWh) or about 65-to-75 euro cents per litre. It is the result of a collaboration project between Bio4Energy systems analysis researchers at the Luleå University of Technology (LTU) in Sweden, companies in the sector and researchers from the RISE Research Institutes of Sweden.
It shows that using residual black liquor from the pulping process—either by separating out the tree polymer lignin and turning it into a petrol or diesel equivalent in a two-step process, or subjecting it to a high temperature in an inert environment (gasification), followed by methanol synthesis plus synthesis to petrol—could push the production cost down to 80 euros per MWh.
Comparing the researchers' findings with those of a 2017 report by the European Commission Sub Group on Advanced Biofuels, the costs are equal to or better than the economic performance of comparable biofuels made from residues from forestry operations.
The northern European country is a world leader when it comes to cutting greenhouse gas emissions and aims to achieve a 70 per cent cut in transport fuels by 2030, compared with 2010 levels; in accordance with Sweden’s Climate Act and Climate Policy Framework from 2017. In a decisive step on the way to do so, in 2018 the Swedish government introduced a binding obligation on fuel providers to reduce greenhouse gas footprint of fuels sold at the pump.
That is, it made a strong gesture in favour of drop-in biofuels.
“The point we are making is that, what we are proposing could be a way to produce biofuels that give deep greenhouse gas reductions… and at the same time give industry a way to circumvent the problem of bottlenecks in the recovery boiler of pulp mills”, Wetterlund said.
“This could bring the double benefit to make the production increase cheaper… and obtain drop-in biofuels that have large benefits in terms of climate change mitigation”, she added.
The researchers’ report is timely given that the competition for drop-in biofuels available on the market today is expected to increase. According to a 2019 report by the Swedish Climate Policy Council, the effect of EU policy targets on Sweden will be a raise in the price of imported biofuels and “make supply more uncertain”.
The Swedish Energy Agency and the f3 Swedish Knowledge Centre for Renewable Transportation Fuels financed the Bio4Energy researchers and partners’ study through its national Collaborative Research Programme. The industrial partners and Bio4Energy also contributed funds.
The researchers' report may be accessed here: Drop-in Fuels from Black Liquor Part Streams—Bridging the Gap Between Short and Long-term Technology Tracks
The collaboration partners are acknowledged as follows:
Yawer Jafri and Fredrik Granberg, Bio4Energy, LTU
Erik Furusjö, Johanna Mossberg and Sennai Mesfun, RISE
Christian Hulteberg and Linnéa Kollberg, SunCarbon
Klaas van der Vlist, Smurfit Kappa
Henrik Rådberg, Preem
Roland Mårtensson, Södra Cell