Wood Pellets Biomass Fuel and Pellet Stoves Boilers

Archive for February, 2008

Food Crop Waste for Fuel

February 29th, 2008

At PelHeat we are strongly against the use of food for fuel, for example grain. Using food for fuel increases its value and thus increases the cost to the consumer. This will increase food costs and increase global famine, so we feel it is a highly unethical process. However when food crops are grown there is a lot of waste biomass left over, and in most cases not utilized, and just burnt in the fields. The video below shows how this waste is been used in China.

With the PelHeat Mobile Pelletizer this waste can be upgraded into pellets, which is a more efficient and convenient fuel than a briquette. Using this waste encourages farmers to grow food crops, as it can then have a dual purpose for food and fuel. So food will be used for food, and the waste for fuel. This will increase food crop supply and increase the availability of a biomass raw material. This will decrease food prices and fuel prices, reducing global famine and developing the use of biomass.

Thank you for your interest

www.pelheat.com

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Posted in Biomass, Videos

Moisture Control

February 22nd, 2008

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

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Posted in Biomass, Making Pellets

What Makes a Quality Pellet?

February 15th, 2008

At PelHeat when we talk about a ‘quality pellet’, it is a term that describes a pellet made from any biomass material, not just wood. The reason I’m stating this is because in the wood pellet market a ‘quality pellet’ refers to a pellet with very low ash, for example 0.3%. Because at PelHeat we wish to encourage the use of all types of biomass, most of the pellets you produce will have a far higher ash content. We define a quality pellet through mechanical durability and moisture content.

Mechanical Durability

Mechanical durability simply refers to how dense the pellet is, and how well it is formed. Pellets that are denser, are of course stronger, the advantage is the pellets withstand transportation better, and work more efficiently in the pellet burner.

When a quality pellet has exited the pellet mill it should have a smooth surface, with little or no cracks. If the pellet is cracking and expanding it is because there is too much moisture within the pellet. Once a quality pellet has cooled, it should be like a colouring crayon. The surface of the pellet should be smooth, and have a surface shine. Wood pellets tend to shine more than others; the most important thing is the pellet smooth compact state. Try tapping the pellet against a hard surface, to see if the pellet stays intact, or if they crumble or easily crush and separate. The length of the pellet is not really that important. The pellet mill uses a knife to keep pellets to a maximum length, as very long pellets are not as mechanically strong, and sometimes are hard to transport through the auger in the pellet burner.

Moisture Content

The less moisture within a pellet the more energy the pellet burner can use. However as you know, moisture is required in the pelleting process, so the target is to keep moisture as low as possible. Try to keep the moisture content of the finished pellet below or about 10%. Pellets with more than 10% will burn, but at the cost of efficiency.

These features are what to aim for, when producing pellets with the PelHeat Mobile Pelletizer.

Thank you for your interest.

www.pelheat.com

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Posted in Making Pellets

Ecoteck Stoves

February 14th, 2008

Ecoteck produce some very well made, stylish pellet stoves. Some units are purely room heaters; others have a back boiler for using with your central heating system.

Heat Output:

The Ecoteck range begins with a 5.6KW room heater, up to 22KW room heater with back boiler.

Corrosive Resistance:

These stoves are specially designed to burn wood pellets, check with the supplier on the ash content that the stove can handle. As wood pellets containing bark may not be suitable.

Maintenance Features:

The Ecoteck stoves use sophisticated control panels to keep room and water temperature to the desired level, without using more fuel than is necessary.

Price Range:

£1,775 (5.6KW) up to £4,815 (22KW)

Treco Green Heat

Contact Treco for more information on the Ecoteck range.

www.treco.co.uk

Thank you for your interest

www.pelheat.com

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Posted in Pellet Stoves, Pictures

Reed Canary Grass Pellets

February 13th, 2008

Reed Canary Grass or RCG is another developing biomass fuel source, unlike Miscanthus, which is grown from rhizomes; RCG can be grown from seed. However the yields per acre of RCG are generally less than Miscanthus. With regards to burning RCG, its corrosion levels are slightly less than Miscanthus, and it produces roughly the same percentage of ash. Again check that your pellet burner can handle this.

We were donated a bale of RCG from a friend, the bale had a moisture content of roughly 30%, which is far too high for pelletizing so we placed the bale In the barn and spread some material out, so it could dry. When RCG is harvested the moisture content is practically ideal for pellet production, this bale however must have left outside. After a week or so we decided to process the RCG to see what would happen. As the material is not as dense as the Miscanthus it was easier to pelletize. With the first run through the pellet mill pellets were formed, but they did not have smooth surface, and were expanding slightly due to the moisture content still been too high. Once the pellet mill was up to temperature we placed the material through the mill again, and hard compact pellets were formed.

Our aim with every potential biomass fuel source it to learn the specific moisture contents required to produce a pellet first time, and design processes to make the process as simple as possible. Developing better knowledge in material preparation will result in high productivity.

Thank you for your interest

www.pelheat.com

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Posted in Making Pellets, Pictures

Miscanthus Pellets

February 12th, 2008

Miscanthus is becoming very popular around the world as a purpose grown biomass fuel. Its high yields result in large quantities of fuel generated quickly, and provides another source of income for farmers. Miscanthus does contain a lot of energy, and will generate a lot of heat when burnt. However it does sometimes cause complications with high chlorine levels causing corrosion, and higher ash levels than some systems can handle.

We were donated a Miscanthus bale from a friend. We had only seen Miscanthus in pictures before, and the real thing surprised us. It is very hard, and looks and feels almost identically like bamboo. It’s strength enables the crop to grow high, producing the high yields.

If you crack the Miscanthus the centre is quite soft, and also contains a lot of energy. The crops had roughly 12% moisture content, we tried to run the material through the equipment, however it was too dry so would not compress. We added a little bit of moisture and the material could then bind together to produce pellets. Below is a picture of a Miscanthus pellet.

Our first impressions on trying to pelletize Miscanthus were that it requires more moisture than other materials, but also sometimes lacks binder. Even though Miscanthus clearly has a lot of binder, as it is so hard, releasing it during the pelletizing process does require the pellet mill to get up to temperature. In one test we actually mixed some wood with the Miscanthus to aid in pellet production. However we are confident with further experiments in changing the moisture content of the raw material we can improve Miscanthus productivity.

Thank you for your interest

www.pelheat.com

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Posted in Making Pellets, Pictures

Straw Pellets

February 11th, 2008

Straw is a common biomass fuel, but in its raw form is difficult to burn, as it is difficult to get the material into the burn chamber quick enough. There are large-scale applications where entire bales are placed in the burn chamber, however these systems are very expensive, and very large.

Converting straw into pellets removes the problem, due to the high density and energy in the pellets; they contain a lot more fuel in a smaller profile. This means small-scale units can take advantage of this widely available fuel. However you must make sure that your pellet burner can handle the high ash and corrosion straw pellets produce.

We were given a few bales of straw from a local farmer, and unlike the wood chippings the moisture of the straw was perfect, creating strong shiny pellets first time. This time we used the 6mm die plate; instead of the 8mm die plate we used for producing the wood pellets.

As straw is more malleable than wood, it is easier to compress into a pellet, so productivity of the pellet mill is higher. We are also very interested in the potential of rapeseed straw. Rapeseed is grown for producing bio-diesel, however the straw is not used and seen as a waste product. This straw will still contain oil, and have a very high heat value. We hope to acquire some in the future to make some pellets.

Thank you for your interest

www.pelheat.com

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Posted in Making Pellets, Pictures

Pellet Burner Maintenance

February 8th, 2008

Burning biomass pellets will result in ash and sometimes a clinker, depending on which biomass the pellet is made from.

Ash

As stated in earlier posts fast growing biomass, for instance energy crops like Miscanthus will produce more ash than wood, but no biomass converted into pellets results in the ash levels from burning coal.
Maintenance levels with regards to ash are dependant on two factors, one which biomass the pellet is made from, and two what the pellets are burning in. If the pellets are burning in a pellet stove compared to a pellet boiler, you will have to empty the ash pan of the stove more often as they are generally smaller.

Biomass ash is a useful commodity and I will talk about this soon.

Clinker

Some biomass because of its low ash melting point will create a clinker. Biomass clinkers are similar to coal clinkers, however they are not as hard, so are easier to break down. When purchasing a boiler, clinker problems should be considered. If the pellet burner does not have automatic features to remove clinkers, then look for a unit that has good access to the burner chamber, so you can easily remove a clinker when required.

Heat Exchanger Tubes

Heat exchanger tubes are where the hot air from burning the pellets heats the water in your boiler, or stove. These tubes will get coated in ash, so require cleaning. Some units have automatic ash cleaning, with moving springs that move up and down the tubes removing the ash. Again if the unit does not have automatic features, easy access is very important for manual maintenance.

Pellet Burner Location

Depending on the biomass pellets you are burning and if you pellet burner has automatic maintenance features, burner location should be considered. For example if you place a manual maintenance unit in the kitchen for example, consideration should be taken if you are happy to be cleaning the unit in that area.

Thank you for your interest

www.pelheat.com

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Posted in Burning Pellets

Wood Pellets

February 7th, 2008

Wood pellets are currently the most common ‘biomass pellet’ that is produced. Below is a picture of some wood pellets we have produced; a friend had cut down a Cherry Tree in his back garden, he then gave us the wood in chipped form. At that time the wood was extremely wet, roughly with 30-40% moisture content, and for making good quality wood pellets, moisture content of roughly 15% is required.

We left the material to air dry in the barn for a few weeks; we then decided to put it through the hammer mill and then into the pellet mill. The material went through the pellet mill, but the end result was basically a woody mush. After a few minutes the pellet mill was up to temperature, so we decided to place the woody mush back into the pellet mill. The third pass produced the quality pellets you see in the picture below, which are extremely dense and hard wearing.

Because of the heat generated in the pellet mill it can be used to create pellets instantly, with a few passes of the material. However this clearly reduces productivity as the material has to be processed multiple times, but it’s a useful feature. There are material driers on the market, but we are also experimenting with low costs solutions in controlling relative humidity to control the moisture content of the raw material. We hope that using this method we will be able to control the moisture content of the material to whatever percentage we require. With the material at the correct moisture content the PelHeat Mobile Pelletizer can be used as a continuous process. With the material entering the hammer mill, through to the cyclone and into the pellet mill. Also correct moisture content first time means that maximum productivity for that material is possible. I will provide more details of the experiment shortly.

In the future we will provide more information on pelletizing different varieties of wood including waste wood and cardboard.

Thank you for your interest

www.pelheat.com

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Posted in Making Pellets, Pictures

Why Make Your Own Pellets?

February 7th, 2008

There are several reasons to produce your own fuel pellets, and they are not all based on environmental concerns. Below are some of the key factors to consider as an individual or a group in the advantages of producing your own biomass pellets with the PelHeat Mobile Pelletizer.

Fuel Costs

As you are too aware the costs of using fossil fuels are accelerating dramatically. Through producing your own fuel pellets from various types of biomass and waste biomass, you will always be in control of the costs of your fuel. Also by taking the pelletizer to the biomass raw material reduces the costs of the pellets, as transportation costs are reduced.

Fuel Availability

As the PelHeat Mobile Pelletizer can upgrade all biomass into pellets, the choice of fuel is up to you. So as different resources become available, you can take advantage of the biomass which you can obtain for the lowest cost.

Fuel Independence

Moving to biomass reduces independence on foreign fossil fuels. This has several advantages including keeping fuels prices stable, increasing fuel availability, and supporting the economy.

Individual or Group Purchase

As the PelHeat Mobile Pelletizer is mobile, the unit is suitable for an individual or group purchase. The unit is self-contained, and can be towed by the average hatchback or saloon to multiple locations.

Local Biomass for Local Pellets

We are promoting the unit to upgrade local biomass into pellets for the local community. The process supports the local economy by:

1. Providing jobs upgrading the biomass into pellets
2. Keeps pellet prices stable
3. Keeps pellet prices low, due to limited fuel transportation

Carbon Neutral

In terms of environmental conservation, the objective should be to make processes as close to carbon neutral as possible. Transportation of fuel over long distances adds carbon to the cycle, so even though the biomass itself is environmentally sound, the complete process is no longer carbon neutral. Using local biomass for local pellets reduces the distances the biomass travels to be upgraded into pellets, and then the distance the pellets travel to the end user.

More Information

Upgrading biomass into pellets using the PelHeat unit is a skilled process, and several factors contribute into making quality pellets. Please read the PelHeat Making Pellets Guide to find out more.

The unit is still in development, however we expect the unit to be available this summer. Once development is finished I will posts, pictures and videos of the unit on the blog.