Straw pellet Production process

The straw pellets are perfect substitute for natural hay / straw to use as the bedding for horses or other animals. The pellets are easy to pour and economical to transport for longer distance. Straw pellets have very similar features as natural straw. In production, no additives are used – only the mechanical pressing operation.

Main export markets for the Straw pellets are: Germany, Belgium, Sweden, France, Finland and Austria.

The straw pellet production starts at the end of field works in summer, usually in last weeks of July. After the crops are harvested, the waste of straw is collected, pressed into transportable rolls and stored.

As the straw has low weight/volume ratio, it is only reasonable to transport it over short distance (~30km). For pellet production, the straw from near-by agricultural industries is collected. Crops from the field of 1 hectare size, given it‘s fertility is 4 tons of grain, can be converted into 1,6 – 2 tons of straw.

After turning into the pellet – the same way as with wood pellets – Straw is again suitable to transport over long distances. Pellets have much better weight/volume ratio, but does not loose the function and features. Very important measure in the straw quality that it has to be clean and clear from any chemicals. Although it is not harmful for animals, it is still not recommended to use it as feedstuff in any case. Reason is the rainwater, soaked by straw while it‘s on field – it may have certain amount of dissolved materials.

Although many crops (rape, barley, triticale, rye) can be successfully pressed into pellets, the most valuable is the wheat. The wheat has light color and good absorption value. The straw pellets can be used for heating purposes as well. Important factor is boiler – it has to be suited for greater amount of ash and slag.
As for heating purpose, the wheat straw pellets are know to produce the least ashes (compared to some other crops, like rape or rye). The straw pellets conform the industry standard norm CEN/TS. Heating values of straw pellets, if used for fuel:

Comparison of calorific value Rape and Wheat straw pellets
Criteria	Rape straw pellets	Wheat straw pellets
Moisture %	10,71	13,53
Ash %	7,41	6,16
Sulphur %	0,07	0,27
netto Q kcal /Kg	4140	4208
netto KJ /Kg	17333	17618
netto MWh /ton	4,81	4,89
Tested by SGS Latvia, certificates: LV1120-0708.1; -0708.2

To keep the high quality of straw during the whole year, it has to be carefully protected from the rain and have sufficient ventilation as well. Otherwise, there is a threat of mold. Before pelletizing, the straw is measured for humidity. Only the straw with < 20% of moisture is passed to the line.

The pelletization process has four major stages: 1) scratching out the straw rolls, 2) cycloning and pressing through the pellet matrix, 3) cutting and transporting to the colling unit, 4) pouring into big bags. In the pressing phase, the pellets are treated in the 90-95°C temperature, killing any biological activity in straw.
 The output from the line of pellets is the 8mm diameter, the pellets are 2-4 cm long. The harder they are pressed, the darker the color (because of heat), also pellets tend to be shiny. Normal pellets are mat, density is 550 to 600 grams per liter, yellowish color. Moisture is always < 15 %, typically 9-10 %. Anual capacity of straw pellets is 6000 tons.

TIPS for stables:
If used as bedding, the average intake of a 10m² stable is about 1300 kg a year. One truckload of pellets is sufficient for one month for the stable of ~ 2000 m² floor space.

BEDDING FOR SMALL ANIMALS – Granulate
For smaller animal bedding – chicken, rabbits – we offer the Granulate. The Granulate is a byproduct of straw pellets. Simply speaking – the smashed pellets. The granulate has the same or better absorption values as normal pellets, just there are more pieces and lower volume/weight ratio. It is more suitable for smaller containers.

Packing of Straw pellets

The straw pellets can be packed into 13 kg, 16 kg or 20 kg small bags; also, into 1100 or 1000 kg Big bags.

The Granulate (smashed straw pellets) can be either packed into 14 kg bag or into 900 kg big bag.

The small bags are transparent, no name polyethylene bags, heat-welded at the end. The Big bags are polypropylene white color no name bags with opening on top and bottom of bags; with special handles to lift with forklift. Big bags are transported onto pellets if the hard-sided (fridge) trailer is loaded and no pallets if the tent (tilt flatbed) trailer is loaded.

The small bags and big bags logistics (certain combinations of bags available):

Logistics of straw pellets: bags and pallets
Bag type	Bags x Pallets	Total weight
1100 kg BB	22 bags x 1,1 t	24,2 t
1000 kg BB	24 bags x 1 t	24 t
900 kg BB (Granulate)	24 pal x 0,90 t	21,6 t
20 kg bag	55 bags x 22 pal.	24,2 t
20 kg bag	60 bags x 20 pal.	24 t
16 kg bag	65 bags x 23 pal.	23,92 t
14 kg bag (Granulate)	67 bags x 24 pal.	22,512 t
13 kg bag	65 bags x 28 pal.	23,66 t

The 20 kg bags packed onto pallets:

The 1100 kg bags, loaded onto a trailer:

Straw pellets Quality Management

The straw can be harvested from variety of crops. Biodela is using only selected, highest quality wheat straw for production of bedding pellets. The premium quality features low moist content, nice yellowish color and tight, low dust pellets. We do not use any grass straw, so pellets would not smell as hay. The straw is clean from any chemicals, additives or glues. It is, however, not recommended to use the straw pellets as feed.

The material for pellet production is kept outside in good ventilation and under cover from rain during warm season. Towards the end of season (spring), as the weather is more humid, only the wheat from covered warehouse will be used for pellet making to avoid any mold.

The major concern for the straw pellets is the molds. Although during process of production, the pellets are treated in 90°-95° C, there is still a threat of mold to appear, if the pellets are not being warehoused correctly. The straw is very sensitive to humidity and standing air. Please be highly advised to take all recommendations for straw pellet warehousing and storage to avoid the loss of quality when stored.

Usage of Straw pellets

Upon possibility to clean and replace the pellets, one should consider lower or higher level of pellets to be spread. For a regular Horse stall 3 x 3 meters area, spread about 100 to 150 kg of pellets. Firstly, remove the old pellets completely. Distribute the new pellets evenly to cover the full area. Otherwise, one should calculate about 12 kg for each floor square meter. There should be a minimum of 5 cm layer covering the floor space.

Then add a little bit of water with a sprinkler, so pellets absorb. Repeat the procedure with a shovel to mix the pellets again and make sure not to leave any dry areas. The stall is now ready for the horse.

Various bedding materials

Straw is one of the best fit to use as bedding. The absorption rate highly and directly depends from material’s inner structure density and from processing degree. However, straw is widely available and relatively cheaper alternative to commonly used alternatives like peat, sawdust or even papers. Importantly, the light density material is problematic to transport and also to store. One should be also aware that the dryer the material, the stronger the protection against atmospheric moisture needs to be maintained.

Consumption of straw pellets

If you are having regular horse stall of about 9 to 10 square meters, you should calculate a pack of 120 kg for every month. Typically the stall stays clean from 2 to 6 weeks. Hence, for a full year cycle, amount needed for 1 stall is about 1.3 – 1.5 tons.

RECOMMENDATIONS

Technologically it’s impossible to dry the straw due to its flammability, unlike the sawdust. Therefore the features of straw pellets are directly dependent on the quality of straw, which is a live material – constantly changing, especially at the end of season in spring.

If certain conditions are present: straw pellets with humidity of more than 12%, bad ventilation (standing air) and warmth (+15 C and more), it becomes a possible thread for mold to grow.

Therefore, we strongly recommend doing the following, after unloading the bags:
– Make sure to open the bags and let the pellets breathe;
– If possible, place the bags in good ventilation (open air) to make sure no humidity is locked in the big bags inside, but also to prevent from outside humidity;
– It is wise to spread the pellets in the stable as soon as possible and sprinkle them with a little amount of water.

There is a small chance of any problems, but Biomasa Forestal SL takes responsibility to inform about any possible threat. However, Biomasa Forestal SL limits responsibility to 10 days after delivery, because we cannot control the storing conditions, once the load is outside our premises. Please pay attention to this; especially in spring time March-June months, when the straw is old and temperature is warm.

An alternative for straw pellets is the 100% natural wood pellets. (approx 15-20 Euro/t more expensive, humidity ~7%, no-mold guarantee).