KL VAINILLINA

The L Vainillina project, which was carried out between September 2016 and November 2020, made it possible to develop a depolymerisation and separation process for high-value bioproducts using kraft lignin (KL), starting at laboratory scale and going up to pilot plant processing (TRL4). Insofar as obtaining vanillin, the initial goal of the project, despite achieving lignin to monomer conversion results up to 7%, it was shown that the low vanillin yields obtained using kraft lignin extracted from eucalyptus wood as a raw material makes the process less competitive commercially in comparison with using other woods, like pine.

Because of that, the initial goals of the project were reoriented taking into account the results obtained up to then. The production process for other kinds of bioproducts was reoriented and it was made industrially viable, given that the results of the economic analysis were very promising.

CENER was responsible for leading and coordinating the project through the various phases. They did evaluations, development and optimisation of the routes for generating and separating bioproducts at both the laboratory scale and in the continuos production phase.

The action plan for the project included:

• Evaluating and selecting the conditions of the production and separation process using KL extracted from black liquor and supplied by ENCE
• Developing and optimising the discontinuous process for producing and separating bioproducts at a laboratory scale using a real substrate (KL obtained from black liquor)
• Modelling, designing and executing the continuos process for producing and separating bioproducts in the pilot plant
• Validating continuous production at the pilot plant at laboratory scale
• Validating the product according to market requirements
• Industrial Viability Analysis Including: Process scaling, mass and energy balances, equipment specifications, supply logistics at the lignin plant and a cost study.

In the first phases, the ENCE company supplied CENER with the amounts of purified KL needed for the tasks, and they also reviewed the work plan and methods to be used. The viability analysis of industrialising the proposed process was done in collaboration between the two entities.

One of the conclusions of the project makes it possible to verify that purified kraft lignin from eucalyptus is within the ranges of molecular weight and presence of functional units expected for this kind of lignin. The results indicate that it is highly condensed, with low molecular weights and very low carbohydrate and ash content, which suggests very high purity, even though there is a high sulphur content in regard to the bibliographic values.

The complexity of designing a separation and purification system for bioproducts made it necessary to change the initial strategy, because the current that was generated while depolymerising the lignin was characterised by high pH and temperature, in addition to a complex composition.

The reconversion of the reactor at the pilot plant was done in September 2019 and it is currently still operative. That was one of the project’s major milestones up to that point, because it marked a step from TRL2 to TRL4.
The project ended and, despite the difficulties, getting operation of the continuous plant under way in 2019, made it possible, in addition to optimising operation, to revalidate the product. The achievement of the initial goals concluded with the viability analysis of subsequent industrialisation.

The analysis indicated that the production process is viable at market prices, even though there are a number of key aspects that still need to be determined, in regard to an industrial scaling stage in the future, which would require, if it were carried out, the involvement of the company. That future development should corroborate the results reached at pilot scale TRL4. At any rate, without including the impact of some improvements described in the project conclusions and that we hope to be able to validate experimentally in the near future, the cost evaluation showed production costs within the market range.
We are very satisfied with the outcome of the project from a technical point of view and with the results obtained. However, as happens with R&D projects, its end is just the point of departure for a new route with more ambitious goals to bring the bioproduct to the market.

To successfully achieve the proposed road map, in the first stage collaboration between the parties will be necessary to validate the bioproduct in consumer goods or products on the market. If the first stage is successful, it would be followed by scaling the process. And finally, the process would be industrialised to commercialise the bioproduct.