For the biomass energy industry to grow we also need to encourage other industries to use stainable crops. The waste or surplus from these other industries can then be compressed into fuel pellets. One of the best biomass energy crops is hemp, as it can produce fuel pellets comparable to wood pellets. Hemp has over 30,000 uses, and even the US government during World War 2 produced videos encouraging farmers to grow hemp for the war effort. Even to this day all boot laces used by the US military are made with hemp fibre due to its strength. The founding fathers of America such as George Washington were also hemp farmers, and made it law that you must use part of your land to grow hemp as it was that important of a crop to society. This particular video is from the marketing director of Hemporium in South Africa on the house they have constructed. The walls of the house are made from hempcrete blocks which is mixture of the woody centre of the hemp plant known as shiv and lime. A chemical reaction takes place and a hard construction block is produced that is both light and high insulating. We are currently restoring an old stone cottage and hempcrete will be used as an interior plaster to insulate the building. Hempcrete is perfect for this purpose as it also breaths well, so will not create issues with damp as common plasters do in old buildings. The biggest issues for hemp usage are the law. For instance there is a huge market for hemp products in the US but US farmers are not allowed to grow the crop. Therefore all hemp products are currently imported from Canada or the raw materials are. Even here in the UK and Europe while you can legally grow hemp with a licence, getting one of those licences is not easy at all. Hemp can address many of the issues we face today but until the legal issues are addressed it will remain as a niche product when it could be a large part of our economic solution.
Before you can even consider installing a pellet mill or pellet plant you need a cheap and secure source of raw materials. Those who have access to cheap natural wood waste are privileged as this waste is becoming harder to find. Ultimately there is not enough of this waste anyway to meet the demands of the fuel pellet market and therefore more focus will move to energy crops such as Miscanthus, Switchgrass and Hemp. So how do you plant and harvest these crops? Which equipment do you use? Well for the most part you can use standard farm equipment. Above is a video of a large swather which will be used to harvest the crops in some cases. The crop will be cut down at the front of the machine, its then reduced in size and made into a single row through the back of the machine. This then makes it easy for a baler to come and collect the material. However the moisture content of the material should also be brought under consideration. To make pellets without requiring additional drying you want a moisture content below 15%. Some energy crops can be harvested at this moisture content, therefore baling straight away is a good idea and then keeping the bales under storage until they are ready for the pellet plant. However if the material is not below 15% then conditioning and turning the energy crops or over wintering the crop are options. However while this can reduce the moisture content naturally there are issues with losses due to mould etc, after all if its a very wet winter you could loose the crop. However there is another advantage which is that is can take out some of the unwanted elements that cause energy crops to be more corrosive than wood during combustion. In terms of the harvesting equipment for processing hemp higher quality blades may need to be used as the fibres can dull lower quality blades. In general though harvesting energy crops will be nothing new to most farmers. Thanks for reading a please comment below.
We do not sell pellet stoves and boilers, however we need awareness of pellet stoves and boilers to increase the demand for pellets and thus pellet mills and plants. One of the leading pellet stove manufacturers in the US are Harman. They have been manufacturing pellet stoves for over 25 years and understand the market far more than most. This video provides some of the differences and benefits to a Harman pellet stove. One of the first major differences is the design of the heat exchanger. Normally tubes are used but Harman have decided to use a flat plate design. The advantages are that there is a a larger surface area to capture heat from the exhaust gases and therefore the efficiency of the stove is improved. Secondly the flat plate design is much easier to keep clean than the tube design. Keeping the heat exchanger clean is vitally important if you want a solid fuel heating system to keep performing adequately. The next unique feature on the Harman stoves is their burn pot design. In their design the feed auger comes in at the base of the burn pot and pushes new pellets in and the old ash off the side of the burn pot into the ash draw. Most other pellet stoves use a drop down burn pot. With drop down burn pots the ash is only removed by the combustion fan speed which remains fairly constant. This means that if more ash if produced with certain fuel pellets ash will remain in the burn pot and eventually combustion will stop. This means with a Harman pellet stoves you can burn standard grade wood pellets, grass pellets, miscanthus pellets, hemp pellets etc. As Harman started to make pellet stoves when there were no wood pellet standards they had to make a stove which was more resilient to changes in ash content. Most of today’s new manufacturers just stick to standards such as the ENplus. The problem with standards such as the ENplus is they cannot be applied to most biomass fuel pellets due to the restrictions on ash content. Thank you for reading and please comment below.
There is a wide range of energy crops that can be used for the purposes of fuel pellets. One of the more popular crops is miscanthus. Miscanthus is a giant grass that is not grown from seed but from cuttings from the roots of other plants called rhizomes. Some prefer the idea of rhizomes as it means the crop is not invasive as can be the case with other crops such as Switchgrass. However the issue with rhizomes is that you cannot do crop rotation. Here is a video of the complete process of planting, growing and harvesting Miscanthus. Once a sufficient number of rhizomes have been collected they are loaded onto the equipment on the back of the tractor. A GPS driven tractor then navigates the field and four operators place the individual rhizomes in the feed shoots. As you can see the growth rate of the plant is impressive. Once the plant has died off and the leaves etc have fallen off the crop is ready for harvest. Particularly as a fuel you want to avoid the leaves etc as much as possible as this will increase the ash content of the fuel as well as increase the risk of clinker formations. Miscanthus at harvest has a moisture content between 10-15% which means it can be made into pellets without a dryer been required. In this video the equipment used shreds the miscanthus into fairly small pieces. These pieces can then be loaded into the hammer mill on the pellet plant, no other previous size reduction is required. We commonly use a 5mm screen in the hammer mill for fuel pellet production from miscanthus for the production of 6mm or 8mm pellets. These particles are then transported into the pellet mill. We use peristaltic pumps for water and vegetable oil addition to alter the compression characteristics of the miscanthus within the pellet press die. We also sometimes add 1-2% modified corn starch binder to improve the density of the pellets. The pellets leave the pellet maker very hot so are then cooled before storage. You can see a video of this process of our small scale miscanthus pellet plant installation.
Greenhouses definitely have their advantages, however when it gets cold outside this can be an issue. Some greenhouses use various heating systems including oil and gas however the costs of running these systems can be very expensive. Not to mention the fact that using fossil fuels maybe responsible for accelerating climate change. This greenhouse however is doing something a bit different. They have a hot air furnace that burns grass pellets. The owner states that a 40lb bag of grass pellets usually heats the greenhouse for 24 hours which is pretty efficient and affordable. The grass pellets are fed into the hopper and an auger in the bottom of the furnace feeds the fuel into a bottom fed burn pot. The advantage of this design is the ash produced is just pushed over the side of the burn pot along with any potential clinker formations. In this instance they have to use a blow torch to get the fire going. However in many pellet boilers like ours you have a hot rod igniter, therefore the fire can start on the command of a thermostat. As you can see within just a few minutes the temperature in the centre of the fire has reached almost one thousand degrees. At this particular greenhouse they used to use coal in this furnace, probably anthracite as that would flow through the auger. They are able to source the grass pellets even cheaper than coal and promote their use as part of their green approach. It’s not stated which grass was used to produce the pellets, the most likely biomass would be Switchgrass. However potentially Miscanthus, Reed Canary Grass or maybe even Hemp. You can easily compress field hay into pellets, however they are much more corrosive than grass pellets produced from the materials above. The advantages of making grass pellets over wood pellets is the raw material can be more abundant and you actually get a much better productivity from the pellet mill. Our pellet plant will produce 400 kg/h on grass pellets, 250 kg/h for wood pellets.
There are many types of energy crop you can grow for the purposes of bio-fuels. Each has its own attributes and should be considered depending on the circumstances of the site and the end product. Here is a video from a farmer in Georgia, USA who is cultivating giant miscanthus grass as his chosen crop. They had looked at other energy crops such as Switchgrass and came to the conclusion that miscanthus on a yield basis was superior to the other crops. Part of their focus is the idea that in the future the US could be much more energy independent and not rely on foreign states for gas and oil imports. Their objective for the crop is for it to be used to produce bio-ethanol, however it can obviously also be used for fuel pellets for pellet stoves and boilers. However with respect to our pellet mills and pellet plants the bio-ethanol market is not a competition but another market. Transportation costs of loose chopped miscanthus or even baled miscanthus are far higher than the transportation costs of miscanthus pellets. Therefore each farmer with a sufficient volume of miscanthus could install a small pellet plant on their farm to produce the pellets ready for transportation. We recently installed a small miscanthus pellet plant. So you see the need for pellets goes beyond the final product to include reducing the transportation costs of raw materials for other products, in this case bio-ethanol. Going back to the advantages of miscanthus, reduced costs with regards to seeding and fertilizer are a positive. Once the rhizomes have been planted the subsequent years are all about harvesting. The video touches on the economic benefits nationally and locally that can be achieved through growing energy crops. However they are also quick to point out that they do not want the miscanthus to compete with food crops, more the crop could take advantage of land which is not suitable for food crops. Miscanthus holds a lot of potential and is one of the key energy crops along with Switchgrass and Hemp. Thank you for reading, please comment below.
Once you have decided which pellet boiler you want to own for your heating needs your next choice is what pellet storage solution you will have. The video to the right is a promotional video from Froling on the pellet storage solutions they offer. The first option they present is their universal suction system. Multiple hoses fit into a manifold which then sends off hoses to three different points on the base of the silo. As stated in the video these suction hoses can pull the pellets from a considerable distance when the pellet store is not next to the boiler. A wedge shaped wall system means the pellets in the hopper will always fall into the trough bottom. In the base of the store there is a horizontal auger which moves the pellets in front of the suction ports. The pellet boiler its self has a small hopper with low and high level sensors. These sensors either tell the suction fan to come on or go off to make sure the boiler always has a sufficient supply of fuel. The wedge shaped hopper can hold the most pellets, but it also the most expensive option and requires the most space. Another alternative is the bag silo which can be quickly assemble. Again the suction system fits into the base of the bag to collect the pellets. If your budget current cannot stretch to such storage solutions Froling do offer an extra capacity hopper fitted to the boiler. This is simply a top loading hopper for bags. However in the future you can still upgrade the boiler for automated pellet filling systems. Finally there is the option of an underground tank. These are quite common in Germany, often positioned under the drive. All the pellet silo/stores can then receive a tanker delivery which means you only need a fuel delivery once or twice a year generally. Another option is to simply build your own storage. We built a structure next to the building where our boiler is kept. Filled the room can hold around 16 tons of pellets which can last us 2 years. When torrefied pellets become possible the fuel store would last for 4 years.
There is a growing number of new designs for camp stoves. In some instances these new stoves are targeting leisure use but in other cases they have real practical applications in developing countries to help use local biomass resources more efficiently. In this video we see the Firebox, this is a folding metal stove which can be quickly assembled and support a cooking pot. It’s a nice design (I presume made from stainless steel) that can easily be stored in a bag. In this video the Firebox is going through a wood pellet test, one stove has the lower ventilation holes closed, the other open. The point of the test is to look at fire temperature and fuel consumption. Through the boiling water test it shows that the Firebox with the lower ventilation holes open was the first stove to boil the two cups of water. Then shortly after (30 seconds to a minute) was the Firebox with closed holes. So while a shorter boiling time is desirable, fuel consumption is really more important. It was then time to see which stove would stop boiling first. After 22 minutes both stoves still have a strong rolling boil. At 27 minutes the stove with the holes open has gone off the boil and the closed hole stove is still going. A little later the open hole stove did appear to pick up most likely due to extra draft from the wind. At 43 minutes it was still possible with the stove that originally had closed holes to keep the water boiling. As the pellets burnt down to coals through opening the lower ventilation holes it was possible to extend the burn time. This video serves as a good example in general how through controlling air flow fuel consumption can be significantly increased. Most pellet stoves and boilers have the ability to alter fan speed so its important to make sure through testing that its set best for your specific pellets. When it gets interesting is if the pellet burner also relies on the combustion fan for blowing ash out of the burn pot. Say you need more ash removal but you do not want more air to the fire, what do you do?
From a consumers point of view wood pellet storage is a very important subject. You know how many tons of pellet fuel you will require and you know you have to keep them protected from moisture. You may also want to avoid manually loading bags into the pellet stove or boiler. For small pellet stoves loading pellets manually is not too hard a task. One bag can last a day or maybe several, and the low height of the stove means you are not lifting the bags too high. However if the property requires a pellet boiler that means your wood pellet consumption is going to be higher, so that means a lot more bags. Also the boiler hopper will be much higher, so you have to lift more bags and lift them higher. This can be very labour intensive for some people and impossible for elderly or disabled users. Therefore wood pellet silos and tanker delivery can be a very practical and affordable solution. The video above shows how simple the process can be. This is a silo which can hold 15 tons of wood pellets to feed a Froling P4 automatic pellet boiler. As this design of boiler also has ash extraction (and maybe compression) this system could run for many months at a time with no attention required at all. 15 tons of pellets could last the average home for several years. However obviously this style and size of silo is impractical for most residential properties. There are however other internal silo and under ground solutions. You may notice that the tanker in this video has only one hose connected to the silo, not two like you may see on other videos. In this instance they are not collecting the dust. You can see at the top of the silo there is a vent pipe, here is where the air and dust will leave the silo. What’s important to note with blown wood pellets is density is very important. If the pellets were not formed under sufficient pressure in the pellet mill this could mean the pellets break apart as they are blown through the tanker and silo. This would reduce their combustion efficiency.
The fist and core market for pellets is the feed industry. Feed pellets are produced for fish, animals and birds. There are many benefits to pellets over loose feed and also to producing feed pellets on a small scale. In pelleted form you can produce a feed which has the exact blend of nutrients, vitamins and minerals required. Also in pellet form the fish, animal or bird will consume the pellet whole with all the ingredients. With loose feed you cannot be sure that all the ingredients have been consumed and ingested. Also if a special medication needs to be administered you can ratio out a specific amount of the special feed pellets and be confident the right amount of medication has been absorbed. Our Mini Pellet Mill can be used to produce pellets for a small farm or be used to produce niche custom feed blends for sale with up to 100 kg/h output. For say an organic farmer or any other farmer, producing your own pellets you will know exactly what has gone into your feed. For larger farms we have our small pellet plants, these can be scaled up to a maximum of 8 presses to achieve a maximum output of 8,000 kg/h of feed pellets. So for chickens for example you could produce growers or layers pellets. Pig feeds are actually very similar in formulation to chicken feeds. You could produce other feed products such as horse treats. We do produce a small hammer mill for our animal feed pellet plants that can mix up to 7 ingredients in precise amounts. This is called the proportioner hammer mill. We often get asked if the same pellet plant can be used to produce other types of pellets besides just feed or fuel. The answer is as long as there is suitable size reduction equipment installed the same pellet line can be used to process any material with a change of pellet mill die. Different dies are required to produce the different diameter pellets required and we also change the compression ratios on the dies to suit different materials.