Quantitative characterization of pore structure of several biochars with 3D imaging

Pore space characteristics of biochars may vary depending on the used raw material and processing technology. Pore structure has significant effects on the water retention properties of biochar amended soils. In this work, several biochars were characterized with three-dimensional imaging and image analysis. X-ray computed microtomography was used to image biochars at resolution of 1.14 $\mu$m and the obtained images were analysed for porosity, pore-size distribution, specific surface area and structural anisotropy. In addition, random walk simulations were used to relate structural anisotropy to diffusive transport. Image analysis showed that considerable part of the biochar volume consist of pores in size range relevant to hydrological processes and storage of plant available water. Porosity and pore-size distribution were found to depend on the biochar type and the structural anisotopy analysis showed that used raw material considerably affects the pore characteristics at micrometre scale. Therefore attention should be paid to raw material selection and quality in applications requiring optimized pore structure.Comment: 16 pages, 4 figures. The final publication is available at Springer via http://dx.doi.org/10.1007/s11356-017-8823-

A novel solution for utilizing liquid fractions from slow pyrolysis and hydrothermal carbonization - Acidification of animal slurry

Pyrolysis and hydrothermal carbonization (HTC) have recently gained much interest in the field of biomass processing. This is due to the process flexibility with respect to raw materials and the range of potential applications proposed for the end products. In addition to the main product, biochar, the processes yield a liquid fraction that has turned out to be challenging to productize. Considering the feasibility of the thermochemical conversion technologies, it is crucial that all the produced fractions can be utilized reasonably and no waste fractions expensive to dispose remain. In spite of active research and development work, unambiguous uses for the liquid fractions have not been recognized yet. Please click on the file below for full content of the abstract

Characterization of biochar pore structure with X-ray tomography

Biochar use as soil amendment can influence both physical and chemical properties of soil. The effects of biochar depend on the raw material from which biochar is derived as well as on the used processing technology and process conditions. One commonly highlighted benefit of biochar application is improved water retention properties of soil. Biochar may affect water retention in direct or direct way. In direct mechanism water is stored and held in the biochar pores while in indirect mechanisms biochar contributes to the soil structural development (aggregation). Please click on the file below for full content of the abstract

Performance of Liquids from Slow Pyrolysis and Hydrothermal Carbonization in Plant Protection

The feasibility of thermochemical biomass conversion technologies can be improved if value-added applications for all fractions can be developed. One of such approaches is the use of liquid by-products from slow pyrolysis and hydrothermal carbonization (HTC) in plant protection. Liquids produced from slow pyrolysis of pine bark, pine forest residues, wheat straw, and willow, and from hydrothermal carbonization of willow, were analyzed in this study. In particular, potential active compounds were analyzed, covering the main volatile, simple organic compounds and numerous phenolic substances. Effectivity tests of the liquids as pest repellent (Arianta arbustorum), herbicide (Brassica rapa), and insecticide (Rhopalosiphum padi) indicated that slow pyrolysis liquid from willow was the most effective pesticide, followed by the liquid from wheat, bark, and forest residues. HTC liquid did not show any pesticidal activity due to low concentration of organic compounds. High content of acetic acid and other carboxylic acids, and the presence of dozens of different phenolic compounds seem to be the main reason for the higher pesticidal activity of willow-derived pyrolysis liquid. Temperature-separated slow pyrolysis liquids proved to be suitable to be used as pesticides. Consequently there is possibility to improve the feasibility of thermochemical biomass conversion technologies remarkably by developing the liquid factions to value-added pesticides. [GRAPHICS] .Peer reviewe

Pyrolyysiöljyn kiintoaineen poisto linkouksella

There is increasing demand in the world for liquid fuels that are produced using renewable and sustainable raw materials. Liquid fuels have higher energy density compared to solid fuels, and liquid fuels are also easier to transport. Fast pyrolysis is a cost-effective way to produce high yields of liquid biofuel out of biomass. Typical fast pyrolysis liquid contains some amount of solid particles. These particles are mainly char from pyrolysis but there is also some ash from the raw material. Solid particles can block or erode pipelines, filters and nozzles. In this thesis work the removal of solids was studied experimentally by using a disc stack separator. Several different pyrolysis liquids produced from either pine sawdust or forest residue were treated with the separator. The solids content of the liquids varied from 0,145 w% to 1,35 w% and with the centrifugation the solids content could be reduced to 0,05 - 0,14 w%. It was discovered that the centrifugation gives better results when it is conducted to fresh oil instead of stored oil. It was also discovered that char particles that are under 10 µm in size cannot be removed from pyrolysis liquid by centrifugal separation.Uusiutuvista raaka-aineista valmistetuille nestemäisille polttoaineille on suurta kysyntää. Nestemäisillä polttoaineilla on suuri energiatiheys kiinteisiin polttoaineisiin verrattuna, ja niitä on helpompi kuljettaa pumppaamalla. Nopea pyrolyysi on kustannustehokas tapa muuttaa biomassaa korkealla nestesaannolla nestemäiseksi biopolttoaineeksi. Pyrolyysiöljyn hyödyntämistä vaikeuttaa siihen tuotantovaiheessa päätyvä kiintoaines, joka on tuhkaa sekä pyrolyysin hiiltojäännöstä. Kiintoaines voi tukkia ja kuluttaa linjoja, suodattimia ja suuttimia. Tässä työssä tutkittiin kokeellisesti kiintoainespartikkeleiden erottamista pyrolyysiöljystä. Erotukseen käytettiin levypakkaseparaattoria eli linkoa. Työssä lingottiin erilaisia VTT:llä mäntypurusta tai metsätähdehakkeesta tuotettuja pyrolyysiöljyjä, joiden kiintoainespitoisuus ennen linkousta vaihteli välillä 0,145 - 1,35 p%. Linkouksella näiden öljyjen kiintoainespitoisuus saatiin parhaimmillaan alennettua tasolle 0,05 - 0,14 p%. Toisaalta havaittiin että pitkään varastoidun öljyn linkouksella ei saavutettu läheskään näin hyvää erotusta. Pyrolyysiöljy tulisikin lingota tuoreena. Öljynäytteille tehdyt partikkelikokojakauman määritykset osoittivat, että linkouksella saadaan erotettua suurikokoiset hiiltojäännöspartikkelit. Pieniin alle 10 µm hiiltojäännöspartikkeleihin linkous ei pure