Several times in articles, which have appeared on the Blog, I have talked about the added benefits of burning biomass as the ash/char can be used as a soil amendment. The following video presentation from a group of Australian scientists explain its benefits in more details, and show the history of the process dates back many hundred if not thousands of years.

History of Terra Preta

Throughout the Amazon the orange soils have been turned black on the top few layers by man, through the process of adding charcoal and ash, and is know in the Amazon as Terra Preta. Scientists today are researching how Terra Preta can store twice as much carbon as other soils. The benefits of adding charcoal to the soil are the soil is then far more efficient at retaining nutrients, to capture and retain water and capture CO2 into the soil.

The reason this research is so important is that it addresses so many of the current issues of today’s world.

Energy

As discussed in the video, one of the best ways to produce Biochar from biomass is through pyrolysis and gasification. Gasification also turns out to be one of the most efficient ways to extract energy from biomass. The biomass is initially burnt in a low oxygen environment, this create the generation of syngas, also known as producer gas and wood gas. This gas can then be used for several purposes in terms of heating applications, running generators for electricity production and by passing the gas through a catalyst can be turned into alcohols such as ethanol and methanol for vehicles and other uses.

Soil Improvement and Restoration

The by-product of gasification is charcoal or Biochar/Agrichar. As the video states, it is possible to use the Biochar on soil to improve productivity and efficiency for growing more food and other crops is important, however it can also address an even bigger issue.

In many places throughout the world, and Australia is good example, soil erosion is a massive issue. Without soil amendments over time the soil terns very dusty and more like sand. This soil cannot hold moisture or nutrients and then plants cannot grow. Plant roots are what also hold the soil together; therefore the problem only gets worse over time. New desserts are forming in the US and Australia among other places because of the lack of sufficient soil amendments and management. As this process continues, the amount of fertile land reduces and less crops can be grown.

Biochar can be added to this soil to increase the percentage of organic carbon and improve the soil for growing crops. Using Biochar can reclaim land that was once lost to soil erosion and turn it back in productive land.

Biochar for Replacing other Fertilizers

Many of today’s modern fertilisers are produced from fossil fuels, which is not sustainable. Biochar can replace many of these fertilizers, which makes the process sustainable and reduces water pollution caused by many other fertilizers.

Carbon Negative

By using Biochar we are effectively collecting carbon from the atmosphere and trapping it in the soil to improve the productivity of crops, which are then turned into Biochar to return to the soil to trap even more. Burning biomass is referred to as carbon neutral, where it is actually possible to be carbon negative. No other renewable energy in the form of wind, solar, geothermal or any other has the ability to be carbon negative.

Biomass Pellets

Upgrading biomass into pellets is a convenient way to use the biomass in gasification systems on a small and large scale. Also the Biochar could be processed into pellets to reduce transportation costs and volumes of the Biochar to where it is needed.

The PelHeat Mobile Pelletizer can process resources including wood into fuel pellets. If you would be interested in registering your interest in the PelHeat Mobile Pelletizer and receiving updates on our progress and informed when the pelletizer is on sale please send us an email to:

Contact @ PelHeat . Com

For more information please visit:

www.PelHeat.com

Thank you for your interest

Middlebury College has installed their own biomass gasification plant on campus. Unlike similar projects carried out by other universities and colleges, Middlebury have made the plant a focus point with glass walls, so people can view into the facility. As this technology is so important to our fuel independent green energy future, its good to see the technology proudly presented, instead of been hidden away.

The biomass gasification plant uses wood chips from the local area, which could include 2-3 loads a day on full operation. The wood chip has to be of a certain size, and so has to be graded, and larger pieces put through a mill. It is also crucial that the moisture content of the wood chip be no more than 50%, as the efficiency of the gasifier is set-up with this tolerance.

The wood chips are feed into the gasifier on demand. On one side of the gasifier the wood chips are heated to a very high temperature in a low oxygen environment. The wood then smoulders and produces wood gas ‘syngas’. The syngas is then feed to the back of the boiler where oxygen is added for combustion, producing heat in excess of 1100 degrees Fahrenheit. The steam produced is used throughout the campus for heating, cooling, hot water and cooking. The surplus steam is used to drive turbines, which produce around 20% of the energy the campus needs.

The ash from the boiler is then collected and sent through a series of cyclone separators, which remove ash and particulates from the exhaust gases. The ash and particulates are then given to a local fertilizer company, to use as a soil amendment for agricultural land. The remaining heat from the exhaust gases is then extracted, to preheat water going to the boiler. The gases are then filtered through a series of filters with 99.7% efficiency. Therefore the largest emission from the stack is water vapour and CO2. And since the fuel was wood, this is therefore a carbon neutral process.

Middlebury should be applauded for designing such a highly efficient process. Combined heat and power units are regarded as been more efficient than simply heat or electricity plants. However Middlebury have gone further and extracted as much possible heat from the exhaust gases and filtered out the particulates. They have also made use of the particulates and ash as soil amendments.

Biomass Pellets and Gasification

Even though the raw material maybe the same, for example wood chips and wood pellets, there are crucial differences which can change the operating parameters of the process and make it easier to operation on an even smaller scale.

Biomass Pellet Size and Density

As mentioned in the Middlebury biomass gasification plant, the wood chip has to be of a certain size and graded and milled to create a consistent graded for the auger system to feed the boiler.

Pellets are a consistent size; therefore a grading and milling system would not be required. Also due to the smaller size of pellets and high-density smaller fuel transportation systems are required to feed the boiler the same quantity of raw material. The higher density of pellets also means the size of the burn chamber can be reduced as pellets produce a higher heat value in a much smaller space. So in general a much smaller set-up could operate on pellets to produce the same amount of energy.

Biomass Pellet Moisture Content

The Middlebury biomass gasifier could operate on wood chips up to 50%. This is an advantage in one sense as it means unprocessed virgin wood chip could be used. However it does reduce how flexible the process is. To operate biomass gasification CHP process on a small scale it is much easier and practical to generate electricity by using the wood gas ‘syngas’ in an internal combustion engine (petrol or diesel) to power a generator. However the high percentage of water vapour in the Middlebury process would make the gas unsuitable.

Biomass pellets on the other hand have much lower moisture content below 10%, and therefore wood gas ‘syngas’ produced from biomass pellets can be used in an internal combustion engine.

The PelHeat Mobile Pelletizer can process biomass including wood into fuel pellets. If you would be interested in registering your interest in the PelHeat Mobile Pelletizer and receiving updates on our progress and informed when the pelletizer is on sale please send us an email to:

Contact @ PelHeat . Com

For more information please visit:

www.PelHeat.com

Thank you for your interest