Eucalyptus Integrated Wood Processing Project

PROJECT DESCRIPTION

BACKGROUND

In the EU, Spain and Portugal are significant producers of eucalyptus, with a total combine cultivated area of 1.4 million ha. Eucalyptus is one of the most common sources of short fibres for the production of wood pulp for making paper. Other products that can be obtained from the tree include charcoal and biochar, dyes and eucalyptus oil.

Eucalyptus plantations generate a significant amount of biomass residues in the form of branches and leaves estimated for Spain and Portugal at some 2.8 million tonnes/yr. Tree residues left on the forest floor increase the risk of forest fires. Simpledisposal methods such as burning on site can also create or contribute to other environmental hazards, including soil erosion and emission of pollutants. Risks of erosion and poor soil quality can be already high because eucalyptus plantations tend to be on relatively steep slopes.

However, there is potential to transform the waste eucalyptus branches and leaves to make new products locally. As well as using them as a source for extracting some of the standard products associated with eucalyptus trees, they could also provide a source of biomass for generating heat and electricity.

OBJECTIVES

The LIFE Eucalyptus Energy project aimed to increase the efficiency of the valorisation of eucalyptus biomass. By adding value to leaves and branches that would otherwise be treated as waste, it aimed to improve the sustainability of eucalyptus forests/plantations. It was expected to improve the quality of the forest, reducing waste and environmental threats at the same time as improving the economic activity of rural areas.

Specific objectives of the project included:

undertaking a technical and economic analysis of electricity production from eucalyptus branches and leaves. It planned to optimise the efficiency and sustainability of this electricity production;

developing intelligent pellets using biochar and studying their effectiveness asa carbon storage tool through a complete carbon balance of the project. It planned to test its reliability and examine the potential use of biochar as a biofuel;

improving the recovery of valuable products from a pyrolysis plant which is used to produce charcoal from eucalyptus. Notably, it planned to demonstrate its potential as a biorefinery, by using the organic phase of the pyrolysis liquids as a biofuel and for producing valuable chemicals;

integrating the whole processes of biomass harvest, pyrolysis, syngas clean-up, electricity generation and biochar utilisation; and

exploring the potential of using other biomass sources, such as municipal green waste or agricultural residues, to supplement the eucalyptus material.

RESULTS

The LIFE Eucalyptus Energy project designed a process for collecting the low-density biomass from Eucalyptus plantations after the cut trees are pyrolysed and high-quality biochar is obtained. The syngas obtained in the pyrolysis process would then be used to produce electric power. This process is an example of circular economy in which the low-density biomass of the Eucalyptus plantations that is usually left in the field as waste is valorised and used to produce electric power and high-quality biochar, which is then applied back in the Eucalyptus plantations to improve the soil quality.

However, the pilot plant designed and constructed to carry out this process did not function as intended, and the project only partially achieved its objectives. While it developed the process and a pilot plant to produce high-quality biochar from the pyrolysis of low-density Eucalyptus biomass, it was not able to produce electricity since the syngas obtained from the pyrolysis contains too much tar. Furthermore, the pilot plant has other weak points, such as the feeding system is prone to blockages that prevent continuous automatic feeding of the pyrolysis kiln, as foreseen in the proposal.

Additionally, although the beneficiaries also developed adequate demonstrations for showing the capacity of the biochar produced to improve the soil quality, they did not have sufficient time to produce significant results, given that at least two years are needed for observation the experiments were launched only six months before the project end. However, this aspect was outsourced to a technological centre, which is committed to monitoring results after LIFE.

Overall, the use of the pilot plant to produce biochar is not innovative or especially valuable, but the designed process is innovative and suitable for other uses beyond that developed by the project. However, the poor performance of the pilot plant, the low management capacity and level of interest demonstrated by the coordinating beneficiary and the uncertainty surrounding the hosting company BFC mean that the likelihood that the project will be continued or replicated is quite low.

Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).