A pile of lignin powder - the "concrete of plant cells".

Making big ships sail sustainably

Wednesday 27 Sep 17
by Frederik Appel Olsen


Joachim Bachmann Nielsen
DTU Chemical Engineering
+45 45 25 29 22


Anker Degn Jensen
DTU Chemical Engineering
+45 45 25 28 41

What if an unexploited natural resource, ready to be turned into sustainable fuels, existed inside all plant material? Postdoc Joachim Bachmann Nielsen's research suggests that it does in the form of lignin – and that large ship engines may sail on it in the future.

On 16 December 2016, Joachim Bachmann Nielsen defended his PhD thesis on “Valorization of Lignin from Biorefineries for Fuels and Chemicals”, which was funded by Højteknologifonden and made in collaboration with University of Copenhagen on the platform Biomass for the 21st Century. Here, three years of research in conversion of the material lignin into liquid fuels was summed up and defended. And Joachim is far from done with the potential offered by lignin:

“There is so much of it. But because it is so difficult to convert into something useful it remains a highly unexploited resource. That is why it is so interesting,” he said in an interview on IDA Universe’s website.

Lignin is a biological polymer that protects plants from fungi, bacteria, and vira. Popularly called “the concrete of cell walls” it can be found in almost all plant material.

But lignin has potential for more than being “plant concrete”. It can, with the right methods and processes, be turned into non-fossil-based fuel and chemicals. Among other things, big ships – which globally consume around 300 million tons of fuel each year – could potentially be sailing on lignin-based fuels. But a huge effort needs to be made for this to happen:

“The problem is that existing technologies are made for converting materials that are not lignin, such as cellulose. But lignin is different: It is an enormous, heterogeneous molecule. So far the most successful, but still not unproblematic, method has been pyrolysis – that is, heating it up without a solvent,” Joachim Bachmann Nielsen says.

Joachim and his team had to try finding an alternative to pyrolysis in order to explore the possibilities of producing lignin-based fuels:

“We did experiments in a so-called batch autoclave which is, basically, a stirred pressure boiler. When we tried using alcohols – more specifically, ethanol – we saw that the lignin was converted enough to yield a lot of oil. Actually it was converted so successfully that it could probably be used as it is in a big ship engine,” he says.

Aiming for the big scale

The most important part of the lignin research is to make the more sustainable fuel available for the industry – to get the ships sailing on lignin fuel instead of fossil fuels. Joachim is continuing the research on the subject with support from DTU’s Proof of Concept Fund (PoC Fund). The aim is to explore the commercial potential of the research results.

“Right now, I’m looking at the process in a continuous installation. This means that, unlike the batch autoclave where everything is “cooked” in one batch, there is a continuous feeding on one end of the installation and then you drain the oil from another end. The advantage here is that we should be able to heat and cool the material much faster, and we expect that this will result in an improvement of the process and product. This also makes it much more relevant to industry: When looking at the final results from this, we will have a better estimate of the commercial potential,” Joachim Bachmann Nielsen says.

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22 OCTOBER 2017