The Water Holding Capacity of Wood Chips as Compared with Common Livestock Beddings

Scientia Horticulturae, 1979

Prasad, M., 1979. Physical properties of media for container-grown crops. I. New Zealand peats and wood wastes. Scientia Hortic., 10: 317-323. Physical properties of New Zealand peats from 5 sources and of wood wastes, bark and sawdust were evaluated in relation to container-grown crops. For comparative purposes, Irish peat was included. All the peats had adequate air space (AS), but the Springhill peat and New Zealand Forest Service bark and sawdust had a particularly high AS (35-38%). Easily available water (EAW) was also adequate in all peats. New Zealand Forest Service bark and sawdust had inadequate easily available water (EAW, 10-12%), but grinding the bark increased this property. All the peats had similar water-buffering capacity (WBC) with the Irish peat having the highest value. The wood waste materials had inadequate WBC. Total porosity was generally adequate in all materials studied and was highest in Springhill peat. The bulk density (BD) was closely related to degree of decomposition (r = 0.95"**) and also inversely related to AS and total porosity (r =-0.82* and r =-0.65, respectively).

Frontiers in Energy Research

Wet storage is synonymous with ensilage, a simple biotechnology that has been used to preserve forage for livestock feed for millennia. In this natural process, organic acids are produced by anaerobic microbial degradation of a small fraction of the biomass, and these acids reduce the pH to levels that minimize further microbial activity and can preserve the biomass for years as long as anaerobic conditions are maintained. These organic acids also result in mild pretreatment with potential to enhance downstream conversion processes, making this an effective storage strategy. However, the degree and significance of this natural pretreatment capability of ensiled storage on downstream processes has not previously been quantified across a range of storage conditions. In this study, the degree of pretreatment was investigated by measuring the reactivity of corn stover fiber to cellulolytic enzymes. Although the results indicated significant improvement in hydrolytic outcomes after wet storage, by a factor of up to 2.4, saccharification of cellulose to sugar monomers was still limited. The results also show that dominance of lactic acid in the ensilage process is key to wet storage (pretreatment) effectiveness as in the livestock feed industry. Lactic acid pKa value is lower than the pKa of other silage acids and lower than typical silage pH. This gives lactic acid the advantage of being in the more dissociated form, with more protons available to facilitate pretreatment hydrolysis. However, unlike the livestock feed industry, where quality feedstock is attainable within very narrow storage moisture range, for biofuel purposes, a wider range of 35-65% is appropriate in achieving a similar quality outcome. This is true both for the immediate fiber response to enzymes and with subsequent pretreatment. This wider moisture range implies more flexibility in harvest schedule without sacrificing feedstock quality, thus alleviating concerns over feedstock quality that biomass suppliers or biorefineries may have.

2013

Wood, like many natural materials, is hygroscopic; it takes on moisture from the surrounding environment. Moisture exchange between wood and air depends on the relative humidity and temperature of the air and the current amount of water in the wood. This moisture relationship has an important influence on wood properties and performance. Many of the challenges of using wood as an engineering material arise from changes in moisture content or an abundance of moisture within the wood.

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Biomass and Bioenergy, 2015

a a Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (CREA), Unit a di Ricerca per l'Ingegneria Agraria (former CRA-ING),

Journal of Renewable Energy, 2013

Moisture content is an important feedstock quality in converting it into energy through biochemical or thermochemical platforms. Knowledge of moisture sorption relationship is useful in drying and storage to preserve the quality of feedstocks. Moisture sorption isotherms for potential feedstocks such as corn stover and big bluestem are missing. EMC values of corn stover and big bluestem were determined using static gravimetric technique with saturated salt solutions (ERH 0.12–0.89) at different temperatures (20, 30, and 40°C). Depending upon the ERH values, EMC values were ranged from 8.0 to 19.6 and 8.8 to 19.2% db for corn stover and big bluestem, respectively, and they followed typical type II isotherm found in food materials. Nonlinear regression was used to fit five commonly used three-parameter isotherm models (i.e., modified Oswin model, modified Halsey model, modified Chung-Pfost model, modified Henderson model, and the modified Guggenheim-Anderson-de Boer (GAB) model) to th...

Energies

The comminution of fuelwood for efficient transportation and handling exposes the material to various biological and chemical decomposition processes. The stockpiling of fuel chips can result in significant dry matter losses (DML) and consequent release of CO2 into the atmosphere. The decomposition processes could be controlled by managing the chip moisture content (MC). MC control by utilizing the self-heating of stockpiled stemwood chips together with wind-driven ventilation was tested in a practical storage experiment, using uncovered and plastic-covered piles as references. The data were analyzed with linear mixed models. The predicted DML was 2.4–3.8% during the monitoring period of 5.9 months, but no significant differences appeared between the storage treatments. The increase in the basic density of the chips decreased DML. On average 1.7–3.5% of the recoverable energy content of the chips was lost during the experiment. The predicted average decline in the MC was ca. 4–8 per...

For water content determinations on organic soils, several researchers have adopted lower oven-drying temperatures in the range 35−90°C (instead of the standardised range for mineral soils of 100–110°C) in order to prevent possible charring, oxidation and (or) vaporisation of substances other than water. However, at too low a temperature, not all of the relevant water is driven off. One major consequence of using such a wide range of drying temperatures for more sensitive materials is to produce considerable disparity in interpolated index values and in deduced correlations between water content and other engineering properties. This paper discusses the pros and cons regarding the oven drying temperature adopted for routine water content determinations on organic sludges and residues. It concludes by recommending a standardised oven temperature of 105–110°C or 105±5°C, a 24-h drying period and a suggested minimum wet specimen mass of 50 g.

This work focused on the determination of equilibrium moisture content (EMC) of some bioplastic materials that could be used for agricultural foil mulch as a source to produce biodegradable drip tubes. Equilibrium moisture content (EMC) is very important to determine the desirable conditions of microorganism's growth, which causes material deterioration and degradation. Thus, this work aimed to determine the EMC of some commercial bioplastic mulch such as (Bioflex, Ecoflex, Chitosan, Mater-bi, and Bi-OPL). The bioplastic materials were put under different temperature (10-50°C) and relative humidity (43-95%) conditions. The data revealed that changing the relative humidity from 43 to 95% has a great effect on both of Mater-Bi and Chitosan, which the EMC increased by 9.87 and 12.22%, respectively. On the other hand, there is a small effect on the EMC with relative humidity changes on each of Ecoflex (1.41%), Bioflex (2.4%) and Bi-OPL (0.5%).

Biomass and Bioenergy, 2014

Crude glycerol, bentonite, lignosulfonate, and softwood residue (wood residue) were investigated in this study as binders for biomass fuel pellets for thermochemical conversion to enhance pellet quality for transportation and storage. The mass fraction of water of the wheat straw and the wood residue used for pelleting were 0.0676 and 0.0949, respectively. Wheat straw with crude glycerol, bentonite, lignosulfonate, wood residue, and pretreated wood residue with crude glycerol were compressed in a single pelleting unit at a temperature of 95 C. The specific energy consumption, density, dimensional stability, tensile strength, calorific value, ash content, and chemical composition of the pellets made were determined. Results showed that the specific energy consumption for wheat straw pelletization significantly decreased with the addition of lignosulfonate, bentonite, wood residue, and pretreated wood residue with crude glycerol. With the addition of binders chosen in this study, the tensile strength of wheat straw pellets was improved with values ranging from 1.13 to 1.63 MPa. There was a significant increase in the higher heating value (17.98 MJ kg À1 to 18.77 MJ kg À1) when crude glycerol, wood residue, and pretreated wood residue were used as binders. The addition of both pretreated and non-pretreated wood residue significantly decreased the ash content of wheat straw pellets.