Europe

Wood ash admixture to organic wastes improves compost and its performance
T. Kuba , A. Tscholl , C. Partl, K. Meyer, H. Insam
Agriculture, Ecosystems, Environment Vol 127 (1-2), August 2008 pp 43-49

A B S T R A C T
Throughout Europe, increasing amounts of wood ash are produced from biomass incineration plants. Most of these ashes are currently landfilled, despite their nutrient and micronutrient contents. The aim of this research was to find a way to return wood ash from biomass incineration plants into the natural cycle
of matter. Three composts from source separated organic waste were produced with 0%, 8% and 16% ash admixture. The composting process was monitored by in situ measurements of temperature and CO2 concentration in the windrows. Maturation of the composts was observed through the parameters basal respiration, microbial biomass,metabolic quotient, Corg, Ntot, C/N-ratio and plant growth tests with cress.

Mature composts were further analysed for potential pH, electrical conductivity as well as for nutrient (Mg, K, P) and heavy metal contents. The process indicators showed that ash admixture had no adverse effects and all legal standards were met. All produced composts met the requirements of the Austrian Compost Ordinance (Compost Quality A or even A+).

In a field experiment – a recultivation trial on an alpine ski-run – we compared the effects of the three composts with an organic fertilizer and a mineral fertilizer. Best plant growth was found on the compost amended plots, followed by the organic fertilizer. Soil respiration measurements indicated a better performance of composts amended with 8% or 16% ash as compared to compost that did not contain ash.

Concluding it may be stated that up to 16% ash admixture to organic wastes does not impair the composting process but is even able to improve the product quality. However, it has to be made sure that only bottom ashes of low heavy metal contents are being used and strict quality control is implemented.

See also:
From Substrate to application: Microbes do the Job Insam et. al. Feb 2008. "What changes are to be expected from Wood ash as an Admixture."

Purchase from Science Direct http://dx.doi.org/10.1016/j.agee.2008.02.012

Process for converting ligneous matter of vegetable origin by torrefaction, and product obtained thereby
United States Patent 4553978
Link to this page:
http://www.freepatentsonline.com/4553978.html

Abstract:
The present invention relates to a process for converting ligneous matter of vegetable origin by torrefaction, and to the product obtained. Wood or any other ligneous matter is subjected in a neutral atmosphere to a treatment of torrefaction at a temperature of between 200° and 280° C., and preferably between 240° and 260° C. for a duration of 30 mins. to 5 hours. The product of the invention is not fermentable, it has a specific mass close to 0.25 kg/dm3, a calorific power of at least about 5000 kcal/kg, a content of fixed carbon of 35 to 40% and can be broken up by hand; it may be used as fuel in boilers and in gas generators.
Inventors:

Yvan, Schwob (Paris, FR)

Application Number: 06/410636
Filing Date: 08/23/1982
Publication Date: 11/19/1985

Torrified Wood links
Tom Miles, March 8, 2008
ECN Torrified Wood
Development of 2nd Generation Pellet fuels in the Netherlands: Torrified Pellets Pell@tlas, European Pellet Centre, Newsletter, January 2008.

ECN B02-technology for Biomass Updgrading Jaap Kiel, Wageningen, 20 November 2007

ECN TOP (Torriefied Wood Pellet) Technology for the Production of Biomass Commodity Fuels. J. Kiel, Poland 2006

Torrefaction for Biomass Upgrading into Commodity fuels J Kiel, IEA Task 32 Berlin, May 2007.

PRE-TREATMENT TECHNOLOGIES,AND THEIR EFFECTS ON THE INTERNATIONAL BIOENERGY SUPPLY CHAIN LOGISTICS: Techno-economic evaluation of torrefaction, fast pyrolysis and pelletisation Ayla Uslu, Department of Science, Technology & Society Utrecht University, the Netherlands and Energy research Centre of the Netherlands (ECN).Biomass Department, Petten, the Netherlands, December 2005.

Torrefaction for entrained-flow gasification of biomass
P.C.A. Bergman, A.R. Boersma, J.H.A. Kiel, M.J. Prins, K.J. Ptasinski, F.J.J.G. Janssen, ECN, Netherlands, ECN-C--05-067,
http://www.ecn.nl/docs/library/report/2005/c05067.pdf

Abstract
A major technical obstacle in entrained-flow gasification of biomass concerns the size reduction and the subsequent pneumatic transport of the biomass powder. The fibrous structure of fresh biomass makes it very difficult and costly to reduce its particle size down to below 500 microns.

Torrefaction, a thermal treatment of biomass in the temperature range of 200 °C to 300 °C in absence of oxygen, is capable of enhance the size reduction characteristics. Torrefaction partially destructs the fibrous structure of biomass and is therefore an interesting pre-treatment option for this application. However, the influence of the torrefaction process conditions and used biomass on the grindability and pneumatic transport properties of biomass is nowhere quantified, as well as the responsible decomposition mechanisms and its kinetics. This work quantifies these relations with the aim to produce design data for entrained-flow gasificationbased bioenergy conversion chains.

An experimental torrefaction programme has been conducted in multiple reactors on both
laboratory and bench scale, varying from 5 cc to 20 l batch wise capacity. In these facilities, intensive parametric testing has been carried out to provide insight in the thermochemical decomposition mechanisms during torrefaction. Subsequently, the produced torrefied biomass has been used to effectuate size reduction and fluidisation experiments to investigate its grindability and fluidisation behaviour. The size reduction experiments have been carried out with a cutting mill, while a cold-flow bubbling fluidised bed has been used to characterise the fluidisation behaviour of (torrefied) biomass.

This work reveals the influence of the torrefaction temperature and residence time, feed particle size, and type of biomass on the main characteristics of product quality, size reduction (power consumption and capacity of a grinding device), and fluidisation (Geldart classification as a function of particle properties). Furthermore, possible mechanisms responsible for the observed changes in grindability and fluidisation behaviour are proposed. Torrefaction leads to a very substantial improvement of the grindability and fluidisation behaviour. It therefore provides a solution to the problems concerned with entrained-flow gasification related to size reduction of
biomass and the subsequent pneumatic transport of the powder.

Conclusions
Torrefaction
In general, the conducted experiments reveal that torrefaction can be applied with a high biomass to solid energy yield ranging from 95-100% within the lower temperature region (<250°C) to 83-95% within the higher temperature region (250-270 °C). At a temperature exceeding 270 °C, the energy yield drops further, but can still be limited when the reaction time is kept short. The corresponding mass yields are consistently lower and range from 90-100% within the lower temperature region and 80% to 90% in the higher temperature range (up to 270 °C). From the analysis of the volatiles, it is concluded that the increased production of water and CO2 with increased temperature mainly explains the interrelation between both yields. The production of these non-combustibles leave the energy yield unaffected while the mass yield is decreased.

The observed order of reactivity of the examined biomass types is larch << willow/beech

Carbon dioxide, deciding for our future
Folke Günther, Holon Ecosystem Consultants, Lund, Sweden, February 26, 2008

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I am also trying to describe the benefits of buried charcoal to counteract the ‘carbon dioxide cloud’ (see my blog), why I am not the least surprised of the reaction of ignorance on he issue. I have been around here in Sweden, trying to lift the mental fog, and have been met with the same surprised skepticism (..if that is so good, why have nobody done it before?)
However, seen from the other side, Lester Brown is quite right. Diminishing the carbon dioxide emissions by 80% to 2020 is just about right (to abot 1 Gt/year). But it must be combined with a massive sequestration (to about 2 Gt annually) ,thus creating a net diminishing of the ‘carbon cloud’ by about 1 Gt per year . For further details, see my blog.

Download the ppt- presentation that seems to be rather clarifying. The drawback is that if takes about one hour to convince a person with it.
FG
-------------------------------------------------------------------------------
Folke Günther
Kollegievägen 19
224 73 Lund, Sweden
home/office: +46 46 14 14 29
cell: 0709 710306 skype: folkegun
Homepage: http://www.holon.se/folke
blog: http://folkegunther.blogspot.com/
folke@holon.se

Also by Folke Gunther, "Carbon sequestration for everybody: decrease atmospheric carbon dioxide, earn money and improve the soil," March 27, 2007, attached.

Terra Preta: Homepage about Anthrohumox in Brazilian Lowland
Gerhard Bechtold, University of Bayreuth/Munchen, Germany, November 2007
Consultant for National (Geo-)Information Systems and Database Setup, for Natural
Resources Assessments


GIS MAP of Terra Preta Sites in the Amazon
Summary of Thesis about Anthrohumox in Brazilian Lowland (2007)


In the Amazon lowland, Oxisol developed in scattered areas to ‘Indian Black Earth’ (Portuguese: ‘ Terra Preta’). High content of C (more than 9%) and ceramics are characteristics. Furthermore, they show weak acidity (but pH not over 6.5), low solum weight and high cation exchange capacity. The very most soil parameters are correlating with the percentage of C.


Terra Preta soil patterns can be found in the Amazon lowland ( map, based on literature research). Visited TP spots in Belterra (close to Santarem) show characteristics about their extension (seldom more than 2 acre), their depth (till about 50 cm with black color of value 3 or lower, in traces till 2-3 m depth) and their transition to the surrounding Oxisols (some few km). Size is correlating with intensity (low value – large areas) and frequency of ceramics in most cases. Due to oxic horizon in the lower Terra Preta, great group ‘Anthrohumox’ is proposed.


There are various theories about their origin. It is proved indeed, that Terra Preta is man made (high phosphate content, ceramics, situation on former village sites). About 1500-2800 years ago the Indios of the area had a strong influence on the Oxisols by their garbage, kitchen, compost and/or mulch ‘farming’ for a couple of hundreds years on their dwelling sites. C14 tests of the samples showed ages of 1780 (+ 270) and of 2260 (+ 280) years, thus dating back to between 800 BC and 500 AD.


Intensive activity of organisms and bioturbation cause a breaking up, a lowering of the solum weight, the loss of some hundred kg soil material per square m and of fine particles (‘only’ 65-80 % clay). High sand content indicates high C content (not in terms relative to other areas). All those characteristics decrease with increasing soil depth.


Strong impact of humic acids react a strong weathering of Si, Al and Fe. Different leaching ratios are discussed in the paper. They show a stronger weathering in the Terra Preta than in the Oxisol (lower Si, higher Al and Fe content). Al occurs mainly as 1:1 mineral (the main parent material), Fe as hematite or –favored by organic material – as goethite (over 70 % Fe d:Fe t).


Strong weathering (Aw climate) causes some characteristics at the depth functions of Si, Al, Fe, but leaching and cristallization is retarded by strong chelation (humic acids complex with metal ions). M o:M d relations quote always high (especially in Al and Mn, less in Fe). Very pronounced peaks of Al o (and of Fe o) are difficult to explain. Illuviation and podzolation seem to be very active. Different chelating groups (M(OH)++ or M(OH)2+) with different stabilities are more reasonable.
Very strong is the influence of the organic material on the content of Mn, Ca, Mg in the upper layers existing a manifold content, compared to the lower horizons, more than 10 times at Ca, due to the exchange sites of the organic substance (high solubility and erosion). At Mg existing fixation in anorganic compounds, e.g. Mg-Al-hydroxydes, at K in mineral interlayers are responsible for the lower percentages of the exchangeable to the total.


The vertical transition to the Oxisol depends on the element: Terra Preta and Oxisol have an almost identical C content at a depth of 1.50 – 2.00 m, an identical solum weight at 2.30 m depth, identical texture only at depths of more than 4 m, identical acidity and Si content at 2 m, Mn and K 40 – 50 cm, Ca and Mg at 1.50 m.


An exceptional profile with nodular laterite concretions (plinthic, plateau laterite) on a slope was analysed. It was found to have high C content and plenty of ceramics (therefore, Terra Preta), but in acidity and exchange capacity (content of K, Ca, Mg) it is more similar to Oxisols. In a different TP profile, burned charcoal induced high C contents and other characteristics of the upper horizons of Terra Preta.


At many elements it is possible to recognize, beside the organic influence, a ‘basic content’ (very low at nutrients) of Ca with 200 – 300 ppm, Mg with 180 – 190 ppm, K with 200 – 300 ppm, K with 50 ppm etc. A melioration by mobilization of these reserves is impossible.


Melioration is imaginable by pH raising (of soil and vegetation), addition of organic substances without fast mineralization and higher bioturbation.


Further research about Terra Preta, surrounding conditions of their development and analytics are described in the paper.

www.biochar.org - balance carbon and restore soil fertility
Christoph Steiner, Germany

Agri-char / Bio-char References: On its potential for carbon sequestration, improved soil fertility and sustainable (carbon-negative) energy production
Rick Davies, updated February 21, 2007

Good link site.

Chemical Analysis: Testing of Barbecue Coal and Barbecue Briquettes
Force Technology, Denmark

Force Technology lists and compares Danish standards with European test methods.

Establishment and Management of Prairie Grasses
Royal Horticultural Society Research, UK, 2007

Establishment of North American prairie grasses by field sowing was investigated at the Royal Horticultural Society Garden at Wisley. This experiment is part of a larger programme of work to investigate the use of North American prairie wildflowers and grasses as a style of planting in gardens and parks in Britain, which is a modern, informal and low maintenance. It is particularly appropriate for amenity planting.