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.
Over the last decade the EU has been pushing for more renewable energy projects. The main objective set is to achieve a 20% share of energy generated from renewable sources by 2020. Now before the economic crisis in 2007-2008 this seemed like a realistic objective, however now its much less clear. Traditional businesses are finding it very hard to secure any loans from the banks. Therefore when you have a new business with a new type of project in renewable energy your chances are even slimmer of securing funding. It’s important to remember with renewable energy its not just a environmental argument but it also effects economics and politics. For instance there are still a few who dispute that climate change is happening at all or that it is not been effected by man. Therefore in most cases I don’t focus on the environmental argument, the economic and political benefits are more than sufficient to support the case for renewable energy technologies such as fuel pellets. For instance local pellet fuel production using local biomass could create a huge number of local jobs. Local jobs are where most economies are currently lacking. The more you have to travel for work the more of your income is spent on transportation. Therefore creating local jobs means more consumable income to be spent on other goods and services. From a political stand point we know that most global issues revolve around fossil fuels such as crude oil and gas. For instance we receive a lot of enquires from eastern Europe. The reasons for this is from a few years ago due to a dispute with Russia over the price of gas, and Russia literally turned off the gas to several countries in eastern Europe. Therefore they are currently interested in biomass pellet production to move away from a dependence on Russian gas. If the EU is serious about meeting their target of 20% they need to address the funding issues or provide tax incentives to renewable energy companies. As usual the solutions are pretty straight forward, but its the politics that gets in the way.
A few years ago EU nations collectively agreed a target that 20% of the energy generated in the European nations should come from renewable energy sources. However these targets were set out before the financial crisis hit and the issues the Euro is currently facing. As the video shows there are multiple forms of renewable energy from solar, wind, wave, geothermal and biomass. Each has its place and should be used where appropriate. We have 16 solar photovoltaic panels on our property producing up to 4kws of electricity. In the future we will install a set of solar thermal panels which will reduce the load on our pellet boiler and reduce our consumption of fuel pellets. Solar PV panels are very popular particularly due to the financial incentives such as FIT’s here in the UK. The issue with solar and wind is that it is difficult to store the energy when not required for times when there is not enough wind and solar to meet demand. Biomass is basically just stored solar energy, and we can process it and convert it into energy on demand. The EU promotional video references biomass as ‘the sleeping giant’ even though really its the oldest form of energy man has used. Modern biomass processes and fuels such as pellet plants and in the future torrefied wood pellets will be a very important part of the renewable energy mix. As you can see in the video wood pellets for use in pellet stoves is shown twice in the video. Solar PV/Thermal panels, small wind turbines and pellet stoves and boilers are just a few examples of how individuals can help to meet the renewable energy target and support the industry. One important factor that is not often mentioned is we need to make our homes better insulated and install low energy appliances. With the current economic crisis the price of oil is relatively low and natural gas is been heavily promoted as a solution. If we are not careful we will end up making the same mistakes with oil and go with the initially cheaper fix, forgetting that the prices will inevitably rise and become less affordable.
In many countries around the world economic and social development is halted due to the lack of readily available and affordable sources of energy. For instance in the poorest places of the world they still mostly use old and inefficient diesel engines to power machinery and water pumps for small local businesses and farm irrigation systems. They cannot obviously produce their own diesel and they do not commonly grow plants that could be used for producing local bio-diesel. However they do produce a lot of biomass waste from food crops which can be used to produce energy. Here is a video from India explaining the general situation with electrical supply many villages face. The government has installed poles in some villages and sometimes they do receive power. However as the villages explain its expensive, infrequent and the voltage is low due to distance from the power stations. However a new approach is been looked at where local biomass can be used in small gasifier to produce gas to run in generators. The first stage of the project is to provide local businesses and farms with power. This will increase the prosperity of local business and generate more income. This means once the plants are expanded to meet the electrical demand of village in general the villages have the income to be able to afford the electricity. This is an example in rural India however this approach is a sustainable model for anywhere in the world with access to biomass. For instance Germany is a big supporter of decentralised energy generation. Biomass generators, solar panels, wind turbines and other sources of small scale energy are feeding into the gird and the power is distributed. This benefits the home owner and removes the need for a number of large scale power plants. For biomass gasifiers to operate efficiently and consistently they prefer a consistent fuel. This is where fuel pellets with their standard density, moisture content and size can work well when a gasifier is designed around them (the coffee car and wood pellet car).
While wood remains the primary biomass energy source those in the industry know this cannot remain the case in the long term. The type of wood used is mainly residue and waste from timber operations. At some point there will not be sufficient waste to support biomass fuel demands. We cannot use these tree’s for sustainable energy source and we need to move to energy crops. Energy crops do include some types of wood but their growth rate is significantly faster than oak and pine. For instance coppiced willow and popular can be used, but there other energy crops these include miscanthus, hemp and in the case of this video switchgrass. Switchgrass requires very low inputs and can easily be harvested each year with impressive yields. For many years universities such as Cornell have use pellet mills to produce fuel pellets from switchgrass and run various combustion trials in several brands of stoves and boilers. You actually get a higher productivity per hour from the pellet press with switchgrass than you do with wood due to its lower density. The video above is a promotion from DuPont on their work to develop liquid fuels from swithgrass. Currently most bio ethanol is produced from corn, however there is evidence that this pushes up food prices, its not that efficient and food should first and foremost be used for food. However you can break down any form of biomass into sugars and produce cellulosic ethanol which is what DuPont are developing. Pellets still have a part to play in liquid bio fuels. Pellets can help to reduce raw material transportation costs and help to make the liquid fuel plants operate more reliably and efficiently. Pellets flow like a liquid and have a low moisture content, therefore they work well in cellulosic ethanol plants. A pellet mill could be installed at each farm or setup at a central farm and operated as a collective. The bales of switchgrass will then be milled and the pellet mill will then produce high density fuel pellets. These will be then transported to the liquid fuel processing plant.
If you browse through our products section you will notice that we do not offer any of our pellet mills or plants with diesel motors and there are several reasons for this which I will state below. First as an example below is a typical flat die pellet mill from China with a single cylinder diesel engine. I’ve actually owned one of these units previously so I can talk about these units with experience. The first point to cover is that these diesel engines are not very efficient and therefore their running costs are significantly higher than electricity. Also as they only have a single cylinder the power is literally on or off. The large fly wheel does try to compensate for the loss of power on the off stroke of the cylinder but its still very easy to bog the pellet mill down and to stall the unit. The manufactures try to cover this issue by putting even larger diesel engines with the pellet mills but this then makes fuel consumption an even more significant issue. As I’ve previously discussed about these pellet presses the lack of material feed control and conditioning is an issue. With the diesel engine there is one source of power at one speed, so its impossible to have hopper with a variable speed auger. With no feed rate control pellet quality suffers along with productivity per hour. Along with a diesel pellet mill a diesel hammer mill is also often supplied, the total fuel cost to produce low grade fuel pellets is not very economical at all. While we do not provide our equipment with diesel engines our Min Pellet Mill could be powered by a small diesel generator and likewise for our pellet plants. The important factor is the actual process power source can take advantage of the control only electrical motors can provide. Thank you for reading and if you have have any questions please post them in the comments section below.
Here is an excellent video of how agricultural wastes can be put to better use to produce biomass fuel pellets. Here you can see farmers in India burning the waste from their cotton harvest in the field. This is a traditional practice and not only waste a lot of biomass it also produces lots of emissions due to the poor combustion of burning low density biomass. A project now pays the farmers for their cotton waste such as the stalks and this material is then used to produce biomass pellets which replaces the use of coal lignite in factories and power stations. 8,500 farmers now benefit from this project, generating them an important additional income while reducing crop burning in the fields. These materials are mixed with sawdust from local sawmills to make pellets in pellet presses. The project actively works with farmers to help them grow more profitable crops which will also generate more waste biomass for the project. The pellet plants currently produce 65,000 tonnes of biomass fuel pellets a year which is very impressive as it also supports 215 local jobs. The workers at the factories that use the pellets benefit from reduced dust and smoke which gives them a healthier working environment. Another benefit is the reduction of 110,000 tonnes of CO2 emissions per year. The project aims to triples its size over the next five years and then expand into other countries. We are also involved in similar project with our small pellet plants are particularly our Mini Pellet Mill. For instance we are now working with a European University that will conduct trials in three locations in Africa to produce biomass fuel pellets from local waste to be used in cooking stoves. In this project instead of the farmers been paid for the waste it’s usually a trade off, in return for the crop waste they are given some fuel pellets for their cooking stove. These projects are very important to reduce deforestation and to reduce dangerous wood smoke emissions in the home.
A lot of the work we do is on projects which are trying to make better use of wastes. A typical example is agricultural wastes. Here is a video of a project where they have developed a downdraft gasifier to burn old corn and corn cobs both in the original state and in pellet form. This is a video from Agbiopower and this is the first video presentation they have produced of their machine in action. The video starts with the narrator explaining just what a clean burn the gasifier can produce. No visible smoke is seen from the stack and this means particulate matter is very minimal. The combustion chamber where the syngas is burnt is composed of three steel barrels end to end. As you can see the gasifier features special fins which will mix the incoming fresh air with the syngas to create an efficient burn. Initially the gasifier is been run on discard seed corn but then they move on to using corn cobs which is a material which is completely under utilized. As the narrator states, material size is important for the operation of a downdraft gasifier. After an initial trial of using corn cobs they then go on to use pellets made from corn cobs. One operator states that compared to using unprocessed cobs, pellets made from corn cobs is like using gasoline. The pellets (if made properly) will have a density roughly six times greater than a corn cob. This increased energy density will mean the gasifier can produce much more energy and the rate of feed can be much slower so the gasifier will run for longer. There is also the case that the process on pellets can be much more automated in terms of the feed system. A typical example would be a small pellet plant installed on a farm and either run as single operation or a co-operative as farmers sometimes do with other equipment. These corn cobs pellets as demonstrated can then be used for heat generation efficiently through a gasifier such as that developed by Agbiopower. Heat is needed on the farm for animal/bird sheds and other applications. For instance it would be an excellent idea to use corn cob pellet to dry corn for food.