What is raw material?

Raw material is the residue you are looking to use in your briquetting production. It is typically unprocessed material from either from wood or agricultural by-products. Examples such as straw, pineapple waste, sugarcane bagasse, birch, larch etc. can be used for briquetting.

But not all raw materials can be used, as the characteristics of the material changes depending on which type you have. 

Below some important characteristics have to be checked for all type of raw materials prior to considering briquetting.

  • Particle size
    Generally the max particle size is 20x5x3 mm in order to avoid feeding problems for the briquette press.
    For consumer type of briquettes the max particle size is limited to 15x5x2 mm
  • Foreign material
    The raw material should be “clean” without foreign material that may cause excessive wear on vital parts like dies, pistons and compression screws.
    It will likewise result in an increased ash content in the finished products.
    An ash content of more than 0,4% of the finished briquettes means, as a rule of thumb, dramatical increase on wear on all vital parts of the press.
  • Moisture content
    As the optimum moisture content for briquetting purposes varies with the raw material, we know from experience that the recommended water content is from min. 6% to max. 16%.
    From 16% and higher quality will deteriorate considerably until briquetting becomes impossible.

Your options are many!

Demolition wood

Demolition wood includes raw materials such as old pallets and similar types of fairly clean raw material.

In some countries with warm climate it is possible to collect the raw material in dry condition, but in other cases the moisture content is often around 25% and the raw material needs to be dried.

The raw material needs to be shredded and hammer milled on a special production line, which includes sand, metal removal and detection. After processing the raw material, it can be briquetted on our standard equipment. The briquettes can either be used for industrial boilers or for consumer logs.

Hardwood

Hardwoods mainly come from trees that reproduce flowers and have broad leaves instead of needles like softwoods have. Most known species are: Alder, ash, beech, cherry, chestnut, elm, hickory, mahogany, maple, oak, rosewood, teak, walnut etc.

Hardwoods can be treated in wet or dry form (below 15% moisture). In wet form the raw material can be logs, branches, chips, saw dust etc., and the process will vary from type but includes chipping, drying and hammer milled prior to briquetting.

In dry form, which typically comes from wood manufacturing, the raw material will be in shavings, chips, off-cuts and might or might not need to be down-sized prior to briquetting.

Hardwood briquettes can either be used for industrial boilers or for consumer logs. Due to the low ash content wood briquettes are often the preferred fuel. Hardwood briquettes normally have a higher density than softwood.

MDF

MDF wastes normally come in the form of dust or chips. Mostly the raw material is dry, and often too dry for briquetting – 6-8% moisture. By adding water up to 10% moisture the raw material can be briquetted well and we have developed a special solution for this.

The briquettes are normally used for fuel in special boilers, but customers often obtain a reasonable sales price for the briquettes and avoid a disposal costs.

Pine

Pine is also a softwood. Softwood is the source of about 80% of the world’s production of timber. Other known species are spruce, fir, cedar, larch and redwood.

Softwoods can be treated in wet or dry form (below 16% moisture). In wet form the raw material can be logs, branches, chips, saw dust etc., and the process will vary from type but includes chipping, drying and hammer milled prior to briquetting.

In dry form, which typically comes from wood manufacturing, the raw material will be in shavings, chips, of cuts and might or might not need to be down-sized prior to briquetting.

Softwood (pine) briquettes can either be used for industrial boilers or for consumer logs. Due to the low ash content wood briquettes are often the preferred fuel.

Softwood

Softwood is wood also known as conifers. Softwood is the source of about 80% of the world’s production of timber. Most known species are pine, spruce, fir, cedar, larch and redwood. Not all softwoods are soft, but here we describe the most common species.

Softwoods can be treated in wet or dry form (below 15% moisture). In wet form the raw material can be logs, branches, chips, saw dust etc., and the process will vary from type but includes chipping, drying and hammer milled prior to briquetting.

In dry form, which typically comes from wood manufacturing, the raw material will be in shavings, chips, of cuts and might or might not need to be down-sized prior to briquetting.

Softwood briquettes can either be used for industrial boilers or for consumer logs. Due to the low ash content wood briquettes are often the preferred fuel.

Torrefied wood

Torrefied wood is regarded as the new “coal”. Apart from having many similarities with coal, it is still renewable energy and believed it will replace many types of biomass within the years to come. The main advantage is that the densified torrefied biomass can replace coal in existing power plants.

The process of producing is a specialized process, which will not be described here, but the raw material is more difficult to densify than normal biomass. C.F. Nielsen has developed special applications and equipment to briquette torrefied wood. The briquettes are mostly used for industrial boilers.

Paper

Paper includes a wide range of raw materials such as: Paper dust, adhesive paper, bank notes, old magazines, cardboard etc.

Generally, most raw materials are dry – with fairly low moisture, however, the structure and type of paper based waste varies very much, so it is important to test the raw material, as quality and capacity will vary from type to type. The process before briquetting normally includes shredding and hammer milling. The briquettes are mostly used for industrial boilers.

Peat

Peat (turf) is an accumulation of partially decayed vegetation or organic matter that is unique to natural areas called peatlands, bogs or mires. Peat is harvested as an important source of fuel in certain parts of the world; however, the raw material is most often regarded as fossil fuel.

There are special processes to harvest the peat and the raw material most often has moisture content between 30% and 40%. Often it needs to be dried prior to briquetting. However, we have been able to briquette the material with moisture levels above 30%. The briquettes are used both for industrial boilers and consumer logs.

RDF/SRF

RDF (Refuse-derived fuel) or SRF (solid recovered fuel / specified recovered fuel) is waste from households. SRF meets an international standard and is becoming a more interesting fuel. Governments are increasing fees for landfill, which makes the fuel interesting as it is considerably cheaper than other biomass.

SRF is a difficult raw material to handle and needs drying, sand removal and down-sizing prior to briquetting. It is recommended to mix the raw material with demolition wood prior to briquetting.

SRF briquettes are normally used for industrial fuel in large boilers for gasification.

Rape straw

Today, rapeseed is cultivated for the production of animal feeds, edible vegetable oils, and biodiesel. The waste straw gives a high yield per hectare. The raw material is collected and stored in bales. Normally, the moisture is below 15%. The raw material needs to be shredded and hammer milled with the right equipment prior to briquetting. Removal of stones and sand should be done during the process. Briquettes can be used for fuel in industrial boilers and for animal bedding. C.F. Nielsen has developed special applications for using briquettes for bedding and biomass.

Pineapple waste

The waste in connection with the harvesting of pineapples consists of leaves and other non-fruit parts. The waste has high water content, but it can be dried in sun depending on season and rain. If the raw material is dried in the sun in the field it is important to manage the collection of the raw material in a professional way in order to ensure a homogenous raw material with moisture content below 15%. However, generally it is recommended that the raw material is dried to the right moisture level, as this will give higher productivity. The raw material is collected and stored in bales. If the raw material is partly dried in the field the equipment should ensure removal of stones and sand during the process. The fibers are strong and needs to be shredded and hammer milled with the right equipment prior to briquetting. Briquettes are mostly used for fuel in industrial boilers.

Peanut shells

Peanut shells are often dumped as an unused waste; however, the raw material has a high calorific value and can make excellent briquettes. The shells are most often dry and normally does not need to be down-sized and can therefore be fed directly into a briquetting press. We have experience turning these shells into valuable, high quality briquettes. This provides a sustainable solution for producers worldwide. Briquettes are mostly used for fuel in industrial boilers.

Napier Grass

Napier Grass or King Grass is similar to Miscanthus; however, the crop is mostly grown in Africa or Asia. When used for biomass in the mentioned regions it is often harvested in green conditions with 60-70% moisture. The crop is harvested 3-4 times per year, so the yield is high. The crop needs to be pre-dried in the sun, then collected and stored in bales. The raw material needs to be shredded, dried and hammer milled by the right equipment prior to briquetting. Removal of stones and sand should be done during the process. Briquettes are mostly used for fuel in industrial boilers.

Olive Prunings

Olive tree cultivation yields a by-product wood from pruning the trees, which currently is neglected and dealt with as a waste. Often it is burned in the field. The raw material can with great advantage be used as raw material for producing briquettes. The prunings need to be collected in the field –either shredded or baled. Even though the raw material is partly dried in the sun it still needs be shredded, dried and hammer milled prior to briquetting. The briquettes can either be used for industrial boilers or for consumer logs.

Miscanthus

Miscanthus is a typical energy crop with a yield of up to 20-25 tons per hectare. In Europe and North America the crop is normally left to dry in the field and can be harvested with a moisture content below 15%. The raw material is often collected and stored in bales. The raw material needs to be shredded and hammer milled by the right equipment prior to briquetting. Briquettes are mostly used for fuel in industrial boilers.

Rice husks

Rice is a crop that is one of the main crops used for food in many parts of the world. The rice husks are however often dumped as an unused waste. The husks are most often dry and does not need to be down-sized and can therefore be fed directly into a briquetting press. C.F. Nielsen has experience turning these husks into valuable, high quality briquettes. Due to the high silica content in the husks, a high wear can be expected when processing the waste. We have developed special wear parts for rice husks. Briquettes are mostly used for fuel in industrial boilers.

Sugar Cane Waste / Bagasse

When processed the sugar cane crop produces sugar juice and bagasse. Bagasse is a valued biomass product, which according to several studies can cover most electricity consumption in rural areas of the world. After processing, the bagasse has a moisture content of app. 45-50% and the raw material needs to be handled and dried in a professional way. Drying in the sun alone will not secure a homogenous fuel and the drying process is necessary to secure moisture content below 15%. C.F. Nielsen presses are optimal for producing sugarcane bagasse briquettes, and we can arrange the whole process, which ensures you high quality briquettes. Briquettes are mostly used for fuel in industrial boilers.

Wine Prunings

Wine production results in a large amount of prunings like branches and twigs. The raw material is mostly neglected and dealt with as a waste. Often it is burned in the field. The prunings need to be collected and baled under dry conditions. The material is shredded and hammer milled on a special production line and later briquetted on our standard equipment. The briquettes can either be used for industrial boilers, for consumer logs or for barbeque.

Reed

Reed is a common name for several tall, grass-like plants growing in wetlands around lakes or along rivers. Reed is an invasive plant, which outmatches native vegetation and lowers the local plant biodiversity. On the other side the crop is a good biomass crop. The crop needs to be pre-dried in the sun, then collected and stored in bales. The raw material needs to be shredded, dried and hammer milled with the right equipment prior to briquetting. Removal of stones and sand should be done during the process. Briquettes are mostly used for fuel in industrial boilers.

Wheat straw

In many countries wheat straw is plowed down and not used for energy. The straw gives a high yield per hectare, and is collected and stored in bales. Normally, the moisture is below 15%. The raw material needs to be shredded and hammer milled by the right equipment prior to briquetting. Removal of stones and sand should be done during the process. Briquettes can be used for fuel in industrial boilers and for animal bedding. C.F. Nielsen has developed special applications for using briquettes for bedding and biomass. Read more about wheat straw in our Foulum case.