Before pellet production can take place a material needs to be relatively dry. With regards to relatively dry, it means between the ranges of 10-20%. Where between the range of 10-20% produces the best pellets is specific that raw material. For example a softwood raw material may prefer 10-15% and say barley straw may prefer 15-20%. Moisture is needed to create the pressure required, how much moisture is dictated by the materials natural lignin content and density. It’s basically a trial and error test to get the best pellets possible. The pellet mill has maximum and minimum tolerances for material moisture content; again how wide these tolerances are is dictated by the raw material. Adding a lubricating agent to the mixture can increase these tolerances.

If you wish to understand the process in more detail visit www.biomasspelletmill.com

If you currently have a raw material and you would be interested in upgrading it into pellets, you can test the moisture content of the material by following the simple steps below.

This moisture test is called a dry weight test. For this test a measured weight of the raw material is dried, and the weight difference is the moisture content. You will need a small metal container, weigh scales and a heat source.

1. Firstly weigh your metal container with no material in it; you need to know this figure to take away from the final reading.

2. Place 100g of the raw material into the metal container, if you can reduce the material into small particles it will be easier to get 100g and the material will dry quicker.

3. Place the metal container on a heat source. Now this heat source should not be too hot, as you don’t want to cook the material, as you will release more than moisture.

4. Frequently weigh the container, if the weight keeps dropping keep placing it back on the heat source. Once the materials weight remains constant the material is now completely dry.

5. Measure the container, then minus the weight of the container, and then take the remaining figure away from the original 100g. So if the reaming figure was 40g (100g-40g) leaves 60g, so the moisture content was 60% (very wet!).

Clearly if the material has a moisture content of 60% it needs to be dried, or mixed with a very dry material to create a suitable average moisture content.

If you would like to register your interest in the PelHeat Mobile Pelletizer please contact us at:

Contact @ PelHeat . com

Thank you for your interest

www.pelheat.com

We have developed a guide to give more information on the pellet production process as a whole. The guide is not specifically about our unit, it is a general summary of the equipment and processes used in the pellet production industry, in small scale and large scale applications. The guide includes the principles of operation, and how parameters must be changed for different materials to produce quality pellets at maximum productivity. The guide is separated in to 10 steps, which include the following:

STEP 1. Size Reduction
STEP 2. Material Transportation
STEP 3. Drying
STEP 4. Mixing
STEP 5. Conditioning
STEP 6. Pellet Production
STEP 7. Sieving
STEP 8. Cooling
STEP 9. Pellet Transportation
STEP 10. Bagging and Storage

If you would like to register your interest in the PelHeat Mobile Pelletizer please contact us at:

Contact @ PelHeat . com

Thank you for your interest

www.pelheat.com

As stated in earlier posts, the key issue that any interested small-scale pellet producer needs to address is the moisture content of their raw material. Any material to make a pellet to burn will be in the range of 10-20%. The exact moisture content is specific to that material, for example wood is generally 10-15%, but straw may require a little more than this to work well. There are purpose made material driers, but they tend to be very large and very expensive, there are more energy efficient and environmentally friendly solutions like solar driers, and I will address these in later posts.

There is another solution!

The basic problem is you have a raw material that is too moist, what you need is another raw material that is dry, to mix the two together to create a raw material of the correct moisture content. Now any biomass material can be used, but there is one material that is in vast quantities and is not fully utilized.

Cardboard

Or more specifically plain packaging cardboard, which has very little contaminates. With the vast quantities of cardboard produced, larger amounts still end up in landfill. Also cardboard cannot be constantly recycled, to make more cardboard. Once it has been recycled 3-4 times the fibres are so broken that they cannot be formed again to create a strong box. So what we are left with are vast quantities of a biomass waste material that has very little use and value, and more importantly a dry material.

At PelHeat we have made 100% cardboard pellets (see above), and they are very strong pellets, their key disadvantage is they have very high ash content, so require a lot more maintenance. Mixing cardboard with another raw material through, perhaps virgin wood could reduce the volume of virgin wood required to produce your required pellets, and you would not need to dry the virgin wood, by mixing the correct proportions of each material to get the right moisture content.

Summary

So mixing cardboard with another material could potentially solve the moisture issue and extend your raw material. You must however check waste handling and burning regulations in your area with regard to cardboard.

Thank you for your interest

www.pelheat.com

As the PelHeat Mobile Pelletizer does not contain equipment for controlling moisture in the raw material and the finished pellets, this is the key issue that interested parties should focus on. As stated in previous posts to form pellets the raw material will require moisture content somewhere between the ranges of 10-20%, which will be specific to that raw material. Also when the pellets exit the unit they are hot, soft and need to cool and dry before they can be used. If you are interested in the PelHeat unit, you first need to create a solution for these issues.

There are three factors, which contribute to how well your chosen area can control moisture; these are Cover, Air and Heat. The more cover, air circulation and heat you provide the better the environment for controlling moisture in the raw material and finished pellets. At one end of the scale is the material completely exposed to the elements, and at the other a purpose made material drier. Clearly this scale also relates to the costs involved in the solution. How you choose to control moisture is optional, below are a few points to consider.

Cover

The more protection from the elements you can give the raw material and pellets, the more predicable controlling moisture will be. This could start from a tarpaulin, up to a purpose made building. A Polly tunnel or green house is a possible solution, as they are portable solutions that will also utilize solar heat to aid the drying process.

Air

The more air circulation, the more efficient the process. This could involve utilising natural ventilation, or forced ventilation with fans. Again a Polly Tunnel in the right location could utilise natural air circulation with natural solar heat to aid the drying process.

Relative Humidity

We are also experimenting in controlling relative humidity to control the moisture content of the material. Below is a link a relative article:

Relative Humidity Control: CLICK HERE

We are experimenting with a dehumidifier that can control the relativity humidity of the air to a specific level, for example 40,45,50…to 80%. As the article states a controlled environment of 80% relative humidity will result in a moisture content of 16%, which is ideal for pelletizing. The temperature of the environment will influence the efficiency of the process, with a higher average temperature being beneficial.

Heat

By increasing the temperature, the more efficient the process. Following our objectives we wish to encourage renewable solutions. So this includes utilizing solar heat or generating heat from another renewable source such as burning biomass to aid the drying process.

Energy and Time

Low-tech drying solutions have a cost advantage; however take longer to complete the process. Where High-tech drying solutions (Dryers) are high in costs, however complete the process much quicker. Also Low-tech solutions require less energy input than High-Tech solutions, which should be taken into consideration. So the three key points to consider are:

1. Energy Input
2. Time Required
3. Cost Involved

You must create a solution that satisfies your individual requirements.

Summary

Before you purchase a PelHeat Mobile Pelletizer you must have a moisture control solution that satisfies your requirements. Below is a link to the PelHeat Making Pellets guide that also includes a low-tech solution to measure moisture content.

Thank you for your interest

www.pelheat.com