Woodchips

Wood chips or wood chips (or chips ) are comminuted with cutting tools wood. Wood shredder however, is produced by crushing of wood with dull, smashing tools. Wood chips are mainly used as raw material for the wood processing industry as well as biogenic and renewable fuel.

Depending on the origin and the names bark chips or wood chips is ( wood chips ) was used.

• 3.1 fuel
• 3.2 mushroom cultivation
• 3.3 Children's Playground

• 4.1 Production and sales
• 4.2 Price

Production

Wood chips are produced with hackers. Mobile or stationary disc, drum or screw hacker chop wood residues, weak wood and other inferior wood (for example from a crawl, clippings from landscape conservation measures or waste wood), which can not be processed into higher value products by the industry. With the increased investment of short-rotation plantations, these are source of raw material for wood chips.

Properties

Wood chips are composed of 100 % wood. You have a calorific value of about 4.0 kWh ( = 14.4 MJ) per kg (depending on the type of wood, at about 20 % water content) and are suitable for automatic feeding, for example, of a heating system by means of screw conveyors, spring tine sweeps, push rod sweeps and conveyor belts suitable.

Water content

Depending on the species several key properties of the wood chips may vary and thus affect the calorific value. This concerns in particular the water content, which has an important influence on the heating value of the wood chips and the shelf life affected. Wood chips with a moisture content of less than 30 % are considered " suitable for storage ", and it is expected with no or any significant microbial degradation of the chips. Contrast, forest freshness chips contain a water content of 50 to 60%. Freshly harvested coniferous wood has a calorific value which is about 2 kWh / kg, at 20 % water content, the calorific value is twice as high, at around 4 kWh / kg

Size and size distribution

Other features are the size and size distribution and bulk density of the chips and the energy density as well as the fuel required for transportation and storage room size. The dense oak and beech wood ( 571 and 668 kg DM / fm ) with a water content of 20 % has a calorific value of 1103 kWh / cubic meter, the less dense poplar wood ( 353 kg DM / fm ), however, has at the same water content has a calorific value of only 682 kWh / cubic meter on.

Bark content

Impact on the quality of the chips also has the bark content. Used for wood chips used as fuel in smaller wood chip for use usually come debarked wood, the lower quality beef cow chips contain larger proportions. They are mainly produced from logging residues, small timber and other low-value timber (for example, from a crawl, clippings from landscape conservation measures). They can be used for the production of particle board or to produce energy in larger systems such as biomass heating and biomass heating plants.

Standardize

For wood chips the European Standard EN 14961, characteristics and classes for water content, ash content, particle size distribution, bulk density space, nitrogen and chlorine content and heating or calorific value of wood chips shall determine as biofuel. In practice, the classification of the earlier Austrian standard ÖNORM M 7133 is also common in Germany.

Wood chips in practice

In practice, chips are classified depending on the source and use in different product categories. A distinction is made in the chipboard or wood -based panel industry between MDF and particleboard wood chips wood chips. These names indicate the different production processes in which the chips are processed into high-value products, such as table and insulation boards. Since each production process, usually even every factory has unique requirements on the commodity, the wood chip market is highly fragmented. Another reason for the fragmentation of the market are the various sources of wood chips. Wood chips are distinguished example of sawmill chips.

Use

Wood chips are used as a raw material for the wood processing industry (for example, pressboard, wood fiber insulation boards, paper industry) as well as fuel for heat and power plants or for woodchip. In addition, they are used as a substrate in mushroom cultivation as well as a material for land cover, for example, in the garden and landscaping.

Fuel

As fuel find chips mainly used in wood chip heating plants and cogeneration plants, in addition to wood chip. Feeding is usually with electrical screw conveyors or drag chain conveyors.

Generally small wood chips (size classes P16 and P45 ) are high quality required for smaller boilers. Cogeneration plants are more flexible with respect to the quality of raw materials. So in large systems is mostly used wood and industrial waste wood ( waste wood) as raw material. The fuel costs are below those of comparable bio-fuels such as wood pellets or logs, however, be taken into account is the need for most fuel-specific procedures.

The use of wood chips as fuel wood in private households in Germany in 2005 was about 580,000 cubic meters, which is about 1.1% of the total energy use of wood. 9 million cubic meters were burned in thermal power stations with a capacity of up to one megawatt, the consumption of large plants was approximately 39 million cubic meters of wood chips or shredded.

Mushroom cultivation

When growing mushrooms chips the size of KL 2-16 alone or frequently used in combination with sawdust, straw, manure or other substances. Depending on the species origin of the wood chips of oak, beech, birch or other trees. The wood chips are soaked in water and then with mycelium ( mycelium, spawn ) was inoculated.

Children's Playground

Wood chips are also approved as a shock-absorbing flooring in playgrounds. However, you must meet the requirements of this DIN / EN 1176 for playground equipment and playground surfaces, ie the grain size must be within the range between 5 and 30 mm. In general, suitable materials by independent institutions (eg TÜV ) for use are certified as playground flooring.

Market

The production of wood chips and especially the foreign trade are clearly increasing, also for years to increase the market prices.

Production and sales

In Germany are mainly softwood chips on the market. In 2007, the production volume for softwood chips was t, according to the Federal Statistical Office 3.80 million in the same period only 41,000 t of hardwood were produced. From the production of inferior qualities of slabs and edgings were 1.98 million tonnes at paragraph determined. In the same period, 4.04 million tonnes of chips or flakes of softwood and 85,000 t of hardwood imported. This is an increase of the quantities imported by 340 % within five years. 63% of the import goods are imported from Austria, the Netherlands and France. The export of platelets and chips in 2007 was 17.94 million tonnes by 66 % over the amount of 2002.

Price

The prices for wood chips have increased in recent years, between July 2004 and July 2009, the increase was around 80%. Between 2010 and 2013, its price remained relatively stable at around 30 euros / MWh.

The retail price for dry wood chips in 2009 (4th quarter ) in Germany at around 119 EUR / t ( 20 % water content and 25 % moisture, 30 m3 of air delivery, including directions to 20 miles and VAT). This corresponds to a price for the petroleum equivalent of 29.71 cents / l Depending on the region, season, quality, water content and delivery distance there are significant differences or fluctuations in the price. An important factor is also the delivery quantity, so that large power plants can have over 40 % spending less on fuel than small plants.