Wood Chip Transportation Research Articles

Wood chip supply from forest to port of loading – A simulation study

Maritime transport facilitates trade with bioenergy feedstocks in the Baltic region. The study aims to provide guidance on efficient organisation of logistics at the port of loading for maritime transport of wood chips. The economic effects of using an intermediate terminal as opposed to direct delivery to port were studied, as well as the relationships between production capacity and storage capacity. Discrete-Event Simulation was used to analyse scenarios where a variable part of the volume is handled through the terminal. The total supply cost, including chipping, transportation, storage and handling at inland terminal and port, as well as loading of the ship, varied between €6.73 and 7.85 per MWh in the different scenarios. The volume passing through the terminal had a significant influence on total cost, showing a supply chain cost increase of €0.78 per m3 (approximately €4.67 per dry tonne) for material delivered through the terminal. The difference in storage cost between port and inland terminal determines whether the terminal volumes affect costs, which was shown by a sensitivity analysis. Even so, the terminal offers a possibility to manage uncertainty, both in production rates and in shipping date, and influences the supply network. The main advantage of using a simulation technique for planning production and logistic flows is the visualisation of risks and margins.

Parameters of Trucks and Loads in the Transport of Scots Pine Wood Biomass Depending on the Season and Moisture Content of the Load

Transport of wood biomass is one of the key operations in forestry and in the wood industry. An important part is the transport of shredded wood, where the most common forms are chips and sawdust. The aim of the research was to present the variability of the total weight of trucks (gross vehicle weight, GVW), the weight of the empty trucks (tare), and loads of chips and sawdust in different periods of the year. Changes in specific parameters were analyzed: GVW; tare weight; trailer capacity; use of the trailer load capacity; bulk volume and bulk density of wood biomass loads; solid cubic meter (m3) and weight of 1m3 of the load; and load weight depending on the season, with simultaneous measurements of wood chips and sawdust moisture. More than 250 transports from four seasons of the year were analyzed in the research. It was found that the total weight of trucks (GVW) was at a comparable level, on average from 39.42 to 39.64 Mg with slight differences (with SD 0.29 and 0.39). The weight of empty trucks was 16.15 Mg for chip-bearing trucks and 15.93 Mg for sawdust-bearing trucks (with SD 0.604 and 0.526). The type of wood material has an influence on the transported volume. The average quantity of load in the bulk cubic meter was 64.783 m3 for wood chips (SD 3.127) and 70.465 m3 (SD 2.516) for sawdust. Over 30% differences in the volume of transported wood chips and approximately 18% for sawdust were observed. The use of the loading capacity of the trailer was on average 72.58% (SD 5.567) for the transport of wood chips and 77.42% (SD 3.019) for the transport of sawdust. The sawdust bulk density was from 0.3050 to 0.4265 Mg⋅m−3 for wood chips and 0.3200 to 0.3556 Mg⋅m−3 for sawdust. This parameter is significantly dependent on moisture content, and the determined correlation functions can be used for estimating and predicting bulk density. The abovementioned absolute moisture content of chips and sawdust also depends on the season, which also affects the selected parameters of wood biomass loads.

Analysis of energy efficiency of forest chip supply systems using discrete-event simulation

Legislative changes have increased the allowable dimensions and weight for heavy transport vehicles in Finland, and this has been essential for the efficiency of wood chip transportation. In a typical forest, the supply of chips from roadside landings to the end-using facilities, such as combined heat and power plants, the balance of production capacities between chippers and the transportation of the chips by truck-trailer combinations substantially influence the performance of the system. The aim of this study was to investigate how new innovative chipper and vehicle types with increased chip carrying capacity would affect the cost and energy efficiency of the entire supply system. A method involving discrete-event simulation was used to investigate efficient solutions for the forest chip supply chain. By running several case scenarios, the aim was to examine the supply costs and efficiencies of new supply systems, and to investigate the difference at supply level between logging residues and small-diameter trees as raw materials.The study confirmed that new vehicle types with an increased chip load capacity can improve the cost, fuel economy and efficiency of forest chip supply. The results indicate that for most scenarios and transportation distances, the use of larger, 69-tonne truck-trailers with electronic trailer steering systems in combination with a highly productive traditional chipper unit was the set-up with the lowest cost per megawatt hour. However, smaller, 52-tonne semitrailer alternative vehicles also increased their competitiveness in cases where the material being transported had a higher moisture content or higher bulk-weight density.

Effects of Intentional Reduction in Moisture Content of Forest Wood Chips during Transport on Truckload Price

Wood chip transportation is a widespread practice in Poland, with distances between forest sites and power or heating plants reaching 300 km and truck transport times of up to 6 h. Because the basic parameter affecting biomass quality for energy production is moisture content, the objective of the presented economic analysis was to determine its effect on the price of wood chips transported by semi-trailer trucks. This paper considered the possibility of drying biomass in the semi-trailer. No external energy consumption was envisioned; the heat needed for drying was obtained from the truck cooling or exhaust systems via heat exchangers. The moisture content of transported biomass had a dual effect on the final truckload price. While it increased biomass amount by adding to its weight, it decreased its price by lowering its calorific value. Mathematical analysis showed that a decrease in wood chip moisture content increased truckload price, justifying research on technological improvements of this process. Simulations indicated that by reducing moisture content during transportation, biomass suppliers increased their revenues approximately € 3.6 to € 30.0 per truckload, which translates into annual financial profit ranging from tens of thousands of euros (EUR) to more than € 23,810.

Energy analysis of poplar production for bioenergy in Sweden

Poplar (Populus spp.) species are currently not widely grown in Sweden but offer interesting options for future large-scale biomass production for bioenergy. This study assesses the average annual net energy yield and the ratio between the gross energy yield and the total primary energy input for well-managed current commercial poplar production systems in Sweden, with and without fertilization with mineral nitrogen (N). The two systems perform similarly, mainly because the yield response to fertilization is estimated to be small. The average annual net energy yields with and without fertilization are estimated at 190 and 179 GJ ha−1 yr−1, respectively. The corresponding energy ratios are 32 and 34, i.e., the total primary energy inputs correspond to only ca. 3% of the gross energy yield, in both cases. Therefore, improving the net energy yield by increasing the harvest level may be considered the most important objective from an energy performance point of view. To do this, more research is needed in order to develop poplar clones that are better adapted to the Swedish climate and identify in which situations poplar responds well to fertilization. At the same time, by reducing the energy inputs associated with the most fuel-intensive activities (wood-chip transportation, chipping, harvesting, forwarding, and stump lifting), greenhouse gas emissions can be reduced. The results should be interpreted with caution since several parameters, especially the yield response to fertilization and fuel consumption rates, are associated with considerable uncertainties.

Experimental Examination and Modification of Chip Suction System in Circular Sawing Machine

The article presents the results of experimental examination of the wood chip suction system in the existing sliding table saw before and after its modifi cation. The studies focused on the extraction hood of the mentioned system. The methodical experimental research of the pressure distribution inside the hood during wood chip removal for the selected rotational speed of saw blades of 3500 and 6000 min-1 with a diameter of 300 mm and 450 mm were carried out. The analysis of the results allowed estimating the areas with insufficient vacuum pressure hindering the organized transport of wood chips in the sliding table saw. That pressure was the main factor infl uencing the decision to adjust the hood construction. To achieve the efficient performance, several changes in the hood geometry were implemented. The results obtained from the experiments were used at the stage of shape modifi cation of the extraction hood. As a result, a new design of the chip suction system was obtained, vastly improving the chip extraction from the tool.

Woodchip transportation: Climatic and congestion influence on productivity, energy and CO2 emission of agricultural and industrial convoys

Aim of this study is to analyze the energy requirements and the CO2 emission of the wood chip transportation in a short supply chain (within a radius of the travelled distance equal to 70 km), using two different types of vehicles: agricultural and industrial convoys. Three itineraries (located in North-West of Italy) with different length (14.5, 36.5 and 68.5 km) but similar in route characteristics were travelled by both the convoys in three different traffic conditions (morning, afternoon and evening) and in two different road states (dry and wet). The energy balance was always positive (from 48 to 335) and truck values were about twice than tractor. The specific energy was directly proportional to the itinerary length and the lowest values were observed in the shortest itinerary (9.44 MJ m−3 for the truck and 17.19 MJ m−3 for the tractor). The net energy highlighted similar values for both convoys (3350 MJ m−3). The CO2 eq. emission per volume unit transported ranged from 0.94 to 8.53 kg m−3, while per kilometer travelled it varied between 1.33 and 4.24 kg km−1. The truck is more efficient than the tractor, especially in dry road conditions, but it was less versatile.

Loader performance during woodchip loading

Woodchip is preferred to other biomass forms because it offers benefits in terms of load density and uniform sizes. Until now, many studies have been focused on woodchip: comminution wood productivity, the environmental impact of chipping operations, woodchip transportation, woodchip storage techniques, but few have been done on woodchip loading. The goal of this work was to evaluate the working time, productivity and work quality for four types pf loader used in woodchip loading. Front loaders and knuckle-boom loader were tested. The highest productivity was observed for a mechanical shovel equipped with a high dump bucket (303 m3 h-1) when handling woodchips to be stored in piles near a wall, while the lowest working rate was achieved by a wheeled loader with a clamshell bucket (176 m3 h-1) in the same work conditions. Frontal loaders storing woodchip in a pile near a wall showed a 12% increase in productivity. Independently of the pile position, the agricultural telescopic loader showed good performance (about 240 m3 h-1). All loaders achieved a good work quality, with the amount of ground losses always lower than 2 m3 (2% of load). From this study it is found that agricultural telescopic loaders equipped with a hinged bucket are the right machine for woodchip loading.

Life cycle assessment of medium-density fiberboard (MDF) manufacturing process in Brazil

Brazil is one of the largest producers of medium-density fibreboard (MDF) in the world, and also the MDF has the highest domestic consumption and production rate in the country. MDF applications are highlighted into residential and commercial furniture design and also a wide participation in the building sector. This study aimed to propose ways of improving the environmental cradle-to-gate life-cycle of one cubic meter MDF panel by means of a life-cycle assessment (LCA) study. Complying with requirements of ISO 14040 and 14,044 standards, different MDF manufacturing scenarios were modelled using Umberto® v.5.6 software and the Ecoinvent v.2.2 life-cycle inventory (LCI) database for the Brazilian context. Environmental and human health impacts were assessed by using the CML (2001) and USEtox (2008) methods. The evaluated impact categories were: acidification, global warming, ozone layer depletion, abiotic resource depletion, photochemical formation of tropospheric ozone, ecotoxicity, eutrophication and human toxicity. Results identified the following hotspots: gas consumption at the thermal plant, urea-formaldehyde resin, power consumption, wood chip consumption and wood chip transportation to the plant. The improvement scenario proposals comprised the following actions: eliminate natural gas consumption at the thermal plant, reduce electrical power consumption, reduce or replace urea-formaldehyde resin consumption, reduce wood consumption and minimize the distance to wood chip suppliers. The proposed actions were analysed to verify the influence of each action on the set of impact categories. Among the results, it can be noted that a joint action of the proposed improvements can result in a total reduction of up to 38.5% of impacts to OD, 34.4% to AD, 31.2% to ET, and 30.4% to HT. Finally, MDF was compared with particleboard production in Brazil, and additional opportunities to improve the MDF environmental profile were identified.

Economic efficiency of the energy wood chip supply chain from Russian Karelia to Finland

ABSTRACTThe development of modern cut-to-length forest harvesting techniques, the availability of non-industrial wood resources, and Russian customs policy have created favorable conditions for the export of wood chips to biomass-based power plants in Finland. Cost of transportation is paramount to the financial feasibility of the bioenergy business, especially long-distance transportation costs. Therefore, the efficiency and costs of cross-border transportation of wood chips were analyzed. The results were compared with the efficiency and costs of transportation of wood chips of Finnish origin. Truck drivers working in the cross-border transportation of wood chips were also interviewed to determine the factors that affect the efficiency of wood chip transportation. The results showed that the highest transportation costs for an 80-km reference distance were those within Finland, at €5.6/m3 loose wood chips, compared to a cross-border route cost of €3.5/m3 loose wood chips. Thus, the proportion of transportation costs to the total supply cost was slightly higher in cross-border transportation (24%) than in Finland (23%) and in Russia (19%). Furthermore, bad road conditions on the Russian side, idle time at the border and the current working schedule of the border crossing point were recognized by truck drivers as the main factors that decreased the efficiency of cross-border transportation.

Experimental investigation on the influence of different grades of wood chips on screw feeding performance

Although basic investigations on wood chip material properties haven been carried out, only few studies deal with transport of wood chips, despite the fact that significant problems are commonly observed when feeding biomass in industrial applications. Within the work presented, basic bulk material properties were measured and experiments carried out with a system consisting of a hopper, agitator and a screw conveyor. The aim of this study was to investigate how three different wood chip grades and two blends of wood chips influence typical design parameters, such as mass flow and driving torque, of a biomass feeding system. The measured basic bulk properties are in good overall agreement with the literature. However, discrepancies were discovered between two standardized methods for determination of the bulk density. The results for the driving torque, mass flow and mass-related energy consumption showed that different grades of wood chips can alter these values considerably. Between two wood chip grades, a twice as high torque was recorded, while a third grade could not be fed due to jamming. One of the major findings of this study is that mixing a rather small amount of a high-fine content grade with the non-feedable grade of wood chips resulted in a blend which inhibited jamming during the screw feeding process.

The energy consumption and economic costs of different vehicles used in transporting woodchips

One of the weak points in the energy-wood chain is the transport of woodchips from the forestry yard to the power station. This operation is critical because the vehicles used must be very versatile to operate under different conditions while maintaining low operating costs. The goal of this study is to implement the information on this topic by examining the different categories of vehicles that are considered to be appropriate for this purpose. For each category of vehicle, the working time, working rate, fuel consumption, energy costs and economic costs were processed.Tests were conducted using both “agricultural convoys” (tractor+trailer) and “industrial vehicles” (lorries).All vehicles were tested on short itineraries of approximately 5, 15 and 25km and on long itineraries of 50, 100 and 200km.The study showed that on routes longer than 25km, lorries had the highest average transfer speed (42kmh−1) whereas agricultural vehicles had the lowest (24kmh−1).The transport costs depending on the distance, the type of vehicle used and the unit cost (€km−1) were high, especially for distances less than 20km (up to 5€km−1).The application of these values to a biomass-fed thermal power unit of 1MW with an annual use of 2000h and a supply of biofuels in the radius of 75km shows that 1500hyear−1 are needed for the bestowal of chips to power the unit (3700tss). The total cost for a lorry is approximately € 148,000year−1 and approximately four times higher for agricultural convoys.The energy required to transport the woodchips is approximately 90MJm−3 loose chips for agricultural vehicles and 35MJm−3 loose chips for lorries. In both cases, these values represent a small claim (2%) of the energy value of the biomass transported.

Use of Wood Biomass in Slovakia

Biomass is organic material, the second most important source of energy. Biomass is a renewable energy source. Wood biomass is used as source of energy for heating in many regions in Slovakia. It is because of its availability. Wood biomass is an easily accessible and affordable source of energy. At present, thermochemical processes, biochemical processes and physical-chemical processes are used for biomass utilization. In the article a suitable technology for combustion of wood chips is proposed. It consists of five main technological parts: transport of wood chips, silo, combustion boiler, and stack.

Uptake of fluids by boreal wood chips: Implications for bioenergy

As part of a long term study of pipeline transport of wood chips for bioenergy applications, we have determined the uptake of two fluids by hardwood and softwood chips from the boreal forest. Water or oil would be the likely carrier fluids in pipelining wood chips for ultimate use as bioenergy (e.g. any of combustion, gasification, pyrolysis to form bio-oil, or fermentation to ethanol). Uptake of water and a heavy gas oil by spruce and aspen poplar wood chips has been measured as a function of immersion time. One unit (mass) of spruce wood chips with an initial moisture level of 53% (wet basis, all percentages expressed as mass %) immersed in water for 48 h absorbs an additional 0.52 units of water to reach a moisture level of 69%, initial water uptake is rapid, with a subsequent very slow increase with time; equilibrium does not appear to have been reached. One unit of spruce chips immersed in heavy gas oil for 48 h absorbs 0.41 units of heavy gas oil to reach an oil content of 29%; uptake of oil is slower than water, and has not reached an equilibrium. Similar figures for aspen poplar are an initial moisture level of 45%, an uptake of an additional 0.57 units of water to reach a moisture level of 65%, and an uptake of 0.51 units of oil to reach an oil content of 34%. For both oil and water, draining in excess of one hour does not reduce the measured uptake of water or oil. The moisture level in wood chips after immersion is not affected by the initial moisture level in the chip; lost water due to drying is quickly reabsorbed. Oil uptake is significantly higher in wood chips that have a lower initial moisture content.

A Life Cycle Assesment of Woodfree Printing Paper Life Cycle Inventory

Life cycle inventory of woodfree printing paper was investigated to establish the methodology and to evaluate the environmental effects. The major conclusions are as follows:(1) Calculation of CO2 emitted from biomass separately from that emitted from fossil fuel allowed identifying the effect of afforestation and fiber recycle on CO2 emission.(2) Papermaking process, as is the process predominantly using the energy from coal/oil boilers, showed largest emission of fossil fuel origin CO2. Wood chip transportation by ship showed largest emissionof SOx.(3) Simulated increase of deinked pulp usage shows little change of total CO2 emission, but, on theother hand, shows increase in CO2 emission of fossil fuel origin.(4) Above mentioned increase in CO2 emission of fossil fuel origin could be reduced burning the part of waste fibers in high efficiency boiler to generate energy.(5) The method for evaluating afforestation and for allocating boiler energy, and ancillaries datacollection would be the subjects for the future study.

The transportation of fuelwood from forest to facility

Secondary transportation from the forest to the utilisation facility is the simplest of the handling phases in transferring fuelwood from its point-of-origin to ultimate processing point, both in its objectives and application. In spite of this simplicity secondary transport is typically responsible for between 20 and 40% of the delivered fuel cost. Truck transportation is in an advanced state of development as the technology employed comes from a very large scale industry that dominates the transport of industrial products in most developed countries. To achieve a full payload within maximum allowable load dimension restrictions the material transported must have a minimum bulk density of about 250 to 280 kg/m 3. While conventional forest products generally exceed this limit, fuelwood in an unprocessed form may have a bulk density of only 120 to 150 kg/m 3. To offset this problem fuelwood material can be compacted before loading, or compacted in the trailer, but, more frequently, it is comminuted before transport. Processing of fuelwood to a chip allows the use of standard transport systems designed for the transport of wood chips for the pulp sector. Major technological gains to improve the transport efficiencies of fuelwood are unlikely in the immediate future. The most important improvements are likely to come from efforts to improve carrying efficiencies in pulp chip transport because of the much greater volume and value of this material carried annually. Any developments will be rapidly adopted by those engaged in fuelwood chip transport.

Electricity use in the Swedish carpentry industry

Because of its large magnitude, industrial electricity consumption deserves attention. Therefore the electricity demands of three carpentry factories in Sweden have been studied. The results show that major savings of electricity can be achieved and that opportunities exist to shift necessary activities so they occur during periods of lower unit-price tariffs. The owner or director of each factory is only rarely a specialist in energy issues and usually does not know how much can be accomplished in saving money in these ways. Nevertheless a short period (a few days) of monitoring, in each of the three factories studied, showed that it would be highly profitable to install larger capacitors for cutting the reactive power: the payback period for such a measure is about a year. Further measurements of the electricity demand revealed that one of the factories used, at maximum, only about one-third of its subscribed power, i.e. the predeclared maximum peak power that the subscriber thinks will be needed. Thus, changing the supply contract or distribution agreement could save at least 25% of the electricity costs each year, and this would be achieved without reducing the expenditure by a single kWh of energy. In addition, even a small carpentry factory has several systems that are energized by electricity, e.g. all the motors for the carpentry machines, the wood-chip transportation equipment and the wood-drying apparatus, and so many opportunities exist to achieve real energy savings.

Reclamation of Wood-Chip Carrier Water

One of the major factors affecting the feasibility of hydraulic transport of wood chips is the effect of substances leached from wood chips into the carrier water during the transit period. An investigation was made to determine the feasibility of treating wood-chip carrier water for pollution control or removal of contaminants, or both, for potential reuse. Several treatment operations and processes were investigated, including biological oxidation, chemical coagulation by lime addition, carbon adsorption, and chemical coagulation followed by carbon adsorption.

Optimization of Pipelines Transporting Solids

A method is presented for optimizing an economic model of a nonclosed network of pipelines transporting mixtures of wood chips and water. A cost function for a single pipe is developed as a polynomial expression in terms of the concentration of solids, C, and the pipe diameter, D. The characteristic response surface generated by this polynomial provide a method for reducing to two the number of pipe diameters which need to be considered for minimizing the cost. The optimization of multiple-pipe networks utilizes the cost function of single pipes and, in addition, requires that continuity of flow of the mixture is satisfied at the junctions. Summaries of numerical examples of a three-line network is given. Costs of pipeline transport of woodchips determined by this method are compared with those of truck and rail for an existing area.