Residue2Heat: Current status of the research on renewable residential heating with fast pyrolysis bio-oil

This challenging EU H2020 project Residue2Heat is now running for about 2.5 years and it is in that sense an unique project that it covers the whole chain of biofuel production to the end-user. I’ll try to summarize the current status of 2.5 years of research on renewable residential heating with fast pyrolysis bio-oil.

Residue2Heat overall concept

This research and innovation project strongly focuses on identifying potential bottlenecks in the value chain for future exploitation of biofuels in the market. From the production side the project aims to produce a standard fast pyrolysis bio-oil (FPBO) from various ash rich residues (forest and agricultural). All the relevant documents will be ready to start a standardization process for residential heating pyrolysis oil in CEN TC19 when the project is finished. As of now we have gathered quite a lot of data and several new and dedicated measurement techniques for FPBO have been developed and will be further validated. It is clear that the properties of FPBO are completely different compared to traditional heating oil and fundamental knowledge in this area is lacking. This is why the project partners are working closely together to gather a deep understanding of the behavior of FPBO. By using dedicated experiments of for example the evaporation of FPBO, detailed numerical models have been developed for both the liquid phase and in the gaseous phase. The latest results will be presented at the International Combustion Symposium later this year in Ireland. We are aware that these detailed models are not that easy to apply by industry and as a result we are developing also global skeleton models which can be used by industry, for example in their CFD software. At OWI we use this detailed knowledge gained by the project partners to develop a 20kW burner for a residential heating system. Recently we’ve made some significant improvements in this area and could achieve very stable combustion of pyrolysis oil (without a pilot flame) with very low CO emissions (about 20 ppm @ 3% O2). The present NOx emissions (180 ppm @ 3% O2) are compared to traditional domestic heating oil relatively high although comparable to pellet ovens. It should be clearly mentioned that by far the largest part of the NOx emissions stem from the fuel nitrogen.

Without a proper assessment of the complete transport chain of FPBO from the production facility to the end-user all kind of challenges can popup during future exploitation. The Residue2Heat project tries to identify these kind of challenges at forehand. Currently we are performing component testing of the fuel storage to combustion chain. The latest results show that standard heating industry components like pumps and filters need special attention when using FPBO. On the other hand partners in the Residue2Heat project also assessed the Green House Gas (GHG) emission savings of pyrolysis oil. It turned out that between 77% and 95% emission savings can be expected depending on the feedstock utilized when using FPBO). These values reveal that the GHG emission saving requirements of both the European Union’s current Renewable Energy Directive (RED) and in the future draft (RED2) are met.

Besides the GHG emission savings, our approach to recover and recycle the ashes during the production of pyrolysis oil showed a positive environmental impact. These investigations revealed that the ashes derived during the FPBO production process, seem to have positive effects on plant growth in small-scale experiments. Moreover, the physico-chemical properties from the aforementioned ashes seem to be similar to those from other type of ashes. A potential application of these ashes is its use as soil amendment in agriculture. These latest results have been published in the journal “Resources, Conservation and Recycling” (https://doi.org/10.1016/j.resconrec.2018.03.018).

Furthermore, a sustainability risk analysis has been prepared for the pyrolysis oil production based on wood residues and its combustion in a small scale residential heating boiler. Various feedstocks, like wheat straw, bark and Miscanthus, have been included in this analysis. In principle, all studied feedstocks can be applied in a sustainable manner for residential heating through FPBO. Some possible risks were identified that need to be monitored and taken care of when applying these feedstocks. The full potential of pyrolysis oil from biomass residues for residential heating will be further explored. Within the project market studies are conducted related to this new fuel and its modified heating system, which will provide further knowledge for a successful market launch. The long-term goal of Residue2Heat is to produce FPBO on the basis of agricultural and forestry biomass residues, which neither can be used for food or feed production nor leads to indirect land use change (ILUC).

Sharing these results and interact with stakeholders (industry, associations and standardization bodies) is essential to bring a new biofuel to the market. A few weeks ago we had the opportunity to present our latest results at the ComSYN workshop and share experiences with other H2020 projects in this area. Similarly, we presented the Residue2Heat project at IEA Bioenergy, Task 34 for Direct Thermochemical Liquefaction to boost the interaction between researchers and commercial entities in the field of biomass pyrolysis. During the European Sustainable Energy Week (EUSEW) 2018 which will take place from 4-8 June in Brussels (https://www.eusew.eu/) we will present and participate in several side events and present some of their latest results. One interesting meeting is organised by INEA and gathers together the beneficiaries of on-going H2020 projects on biofuels and alternative fuels to identify synergies and establish collaborations & information exchange between those projects.

The Residue2Heat project will run for another 1.5 year. There is still quite a lot of work to-do. I’m very happy with what we have achieved as consortium in these 2.5 years and confident that we achieve what we have promised to do as consortium.

Acknowledgement: The Residue2Heat project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No. 654650