Feasibility of Using Wood Chips to Regulate Relative Humidity Inside a Building: A Numerical Study

The use of bio-based materials in buildings has become more and more significant last years.In most of the cases,their health properties and natural provenance have made them a great solution to face global climate warming and the new policies to reduce building energy consumption.In many thermal problems,biobased materials can allow to optimize the building thermal behavior according to its energy consumption and inside comfort conditions.So it is when they are used as an insulation material in the building.However,it is not the case in this paper.In fact,the bio-based matter is rather used as a desiccant wheel to control air conditioning inside the building.The aim of this paper is to numerically verify if it is possible to use a bed of wood chips as a hygroscopic material(or a desiccant matter)in order to modify the relative humidity inside the building in Reunion Island and so improve thermal comfort.A simple model of heat and mass transfer between a bed of wood chips and building inside air has been set up and implemented into a validated building simulation code named ISOLAB.Numerical simulations were set up for the four climate zones of the island regulations and a focus has been made on the low altitude one(with high,solar irradiation,temperature and relative humidity).Simulation results give the thermal behavior of the building particularly the temperature and relative humidity of inside air temperature,and temperature and moisture content of wood chips.The obtained results lead to determine if the wood chips bed is suitable for the reference building and to verify its technical feasibility(wood species,size of the bed,integration to the building,etc.).The results show that the use of a WCB help to decrease the building inside air temperature and water content up to 10°C less and 11.6 g.kg-1 less.These are the ways to improve inside comfort conditions.Indeed,comfort analysis have shown the possibility to significantly increase building users’thermal comfort when coupled with a fan and natural ventilation,like the regulation needs for low altitude climate.In this case,a gain of 68%of year time is achieved for a building equipped with WCB system compared to one without it(6308 hours of comfort over a year with the WCB against 350 hours without WCB).So the WCB seems to be able to help reducing cooling loads in tropical climate conditions.

Metal and Composite Intermodal Containers in Comparative Cold Tests with Wood Chips

Intermodal containers have many advantages in the bulk supply chain, but idle times may cause freezing problems for containers in terminals and long-lasting deliveries, especially during the winter time in Nordic conditions. The aim of the cold tests was to study metal and composite containers’ ability to tolerate wood chips freezing into the inner surface of the container. Two of the containers were normal metal containers and one was a composite container. The loaded containers were put inside the laboratory hall, the temperature of which was -30°C, and kept there for variable times: less than 24 hours. The inner surface of one of metal containers was treated with a special coolant, EC1. After the test, the chips were unloaded, and the container walls were checked to determine whether there was any material left on them. The test results indicated the advantages of composite containers having a thermally insulated structure without freezing problems. At the same time, chips were freezing badly onto the floor of both metal containers. A frozen chip layer with a thickness of approximately 50 cm - 60 cm was stuck to the floors. As such, EC1 did not seem to prevent the freezing of the chips onto the inner surfaces. The results proved that intermodal logistics of truck and train transportation would be more suitable for composite containers than for metal containers in the winter time in Nordic conditions.

Influence of lignin content on enzymatic saccharification of poplar wood chips by different pretreatment methods

Bioconversion of lignocellulose to fermentable sugars is a promising approach to produce potential bio-based energy and chemicals.Pretreatment is the key step to remove or delocalize lignin in lignocellulose,thus improving enzymatic saccharification efficiency.In this study,three kinds of pretreatment methods(ethanol,bisulfite and sulfate)were employed to produce substrates with various lignin contents which were subsequently subjected to biological saccharification processes.Results showed that a lower lignin content led to a higher fermentable sugar yield based on reducing sugar release for all samples.Additionally,the sulfate pretreatment improved the enzymatic saccharification efficiency in a greater extent than the others.Fourier transform infrared(FTIR)spectroscopy confirmed the structure changes during pretreatment.

RESEARCH A NEW TOOL STEEL AND ITS PROPERTIES FOR MAKING WOOD-CHIP CUTTING KNIVES

On the basis of analyses of service conditions and properties requirements of wood chip cutting knives, an alloying scheme was formulated and a kind of new tool steel was developed. Parameters for its heat treating process and mechanical properties were systematically investigated and optimized. Satisfactory results were obtained on the knives in practice.

CHEMICAL AND PHYSICAL CHANGES OF STEAM TREATED WOOD CHIP

High dimensional stable particlcboards could be produced by usisng saturated steam treated wood chip at elevated pressures. Sample Particleboards were made from wood chip of Birch (Platyphylla). The component changes of steam treated wood chip were analysed by infrared. Infrared spectra demonstrated that the hemicelluloses in steam treated chip were less than those in untreated chip. This is one of the main reasons why steam treatment could improve particlcboard stability. The free radical concentration of steam treated chip surfaces was analysed by ESR spcctroscopy. The results showed that free radical concentration of treated chip surface was higher than that of untreated chip surface. The glueyncss of chip increased and particlcboard resin content decreased.

Effect of Mulching on Uptake of Copper and Nickel from Smelter-Polluted-Soil by Planted Tree Seedlings

Our aim was to determine the long-term effect of a mulching treatment on copper (Cu) and nickel (Ni) uptake by tree seedlings (Pinus sylvestris L. and Betula pubescens Ehrh.) from smelter-polluted forest soil in southwesternFinland. A mulch cover spread onto polluted barren soil did not have a clear positive impact on the biomass production and it did not decrease metal uptake by planted tree seedlings during a ten-year study period. In contrast, the Cu uptake by the above-ground parts of birch was increased as a result of mulching, although there were weak indications of slightly reduced availability of Cu and Ni to roots in the case of both species. As Cu and Ni concentrations of foliage and bark have been shown to be strongly affected by surface deposited metal containing aerosols, only the woody compartments were used as indicators of metal uptake from soil. The Cu:Ni ratios of woody compartments were lower than those predicted by the Cu:Ni ratios of soil suggesting that the soil extraction method used gives an underestimation of available Ni in relation to Cu. The lower soil Niexch concentrations on the mulched plots compared to the controls were in agreement with the slightly lower root Ni concentrations in the mulch treatments.

SIMULATION OF O_(2)-BLOWN CO-GASIFICATION OF WOOD CHIP AND POTATO PEEL FOR PRODUCING SYNGAS

Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel.However,disposal/recycling this peel remains a challenge due to the stringent environmental regulations.Consequently,there is a lack of an appropriate recycling and valorization methods of potato peel.Gasification is an effective technology for producing syngas and an ecofriendly waste disposal approach.Syngas is an important industrial intermediate to produce synthetic fuels and chemicals.To develop an ecofriendly and cost-effective valorization approach for potato peel,this study used a mixture of woody biomass(i.e.,wood chips)and potato peel to produce syngas by co-gasification using O_(2) as the gasifying agent at a constant equivalence ratio of 0.3 using Aspen Plus simulation software.The influences of gasification temperature and wood chip/potato peel weight ratio on the carbon conversion efficiency(CCE),and product gas composition(molar fraction)and lower heating value(LHV)of product gas were investigated.This simulation indicated that a positive synergistic interaction occurs between wood chips and potato peel in co-gasification process in terms of an increase in CCE by comparing the arithmetic value and real value at all simulated wood chip to potato peel weight ratios(44.9%to 85.8%,46.5%to 76.2%,and 48.1%to 78.6%at ratios of 25:75,50:50,and 75:25,respectively,for wood chips to potato peel).While the molar fraction of H_(2) and CO decreased continuously with increase in the weight percentage of wood chips in the wood chip-potato peel mixture from 0 wt%to 100 wt%(H_(2),at 42.1 mol%to 41.4 mol%;and CO at 44.0 mol%to 40.4 mol%),accompanied by a decrease of the LHV of the product gas(10.3 to 9.78 MJ·Nm^(−3)).The study concluded that co-gasification for producing syngas is feasible and environmental-friendly option to recycle and valorize potato peel.