Answers to frequently asked questions
What is pyrolysis?
Pyrolysis is a chemical process by which organic and biological materials (biomass) decompose into simpler chemical compounds. The process occurs when biomass is heated to temperatures greater than 200°C in the absence of oxygen. As the products of pyrolysis have not reacted with oxygen, they can easily be utilized for other applications such as fuels, industrial chemical compounds, soil amendments, and carbon capture and storage. Pyrolysis can be used to produce either bio-coal or biochar depending on the temperature. Biocoal is produced by pyrolysis around 290ºC, while biochar production is usually carried out around 500ºC.
Is pyrolysis the same as combustion and incineration?
No. Combustion is the chemical process that occurs when materials are heated in the presence of oxygen. During combustion materials react with the oxygen as they burn. There are many everyday examples of this such as campfires, candles, and the burning of gasoline inside a car engine. Unlike pyrolysis, the primary products of combustion are carbon dioxide and ash, as these have completely reacted with oxygen and in general cannot be collected and utilized.
Incineration is the controlled combustion of waste materials (such as biomass) in order to dispose of the material and produce energy in the form of heat.
Does pyrolysis require energy or fuel?
Yes. Pyrolysis requires heat in order to proceed, and this heat requires a source of energy or fuel. The Diacarbon process uses the combustion of propane (a clean burning fuel) in order to initially achieve the required heat. However, once the process is underway one of the by-products of pyrolysis, syn-gas, is used as the primary fuel. As such, the process is self-sustained and does not require the input of external energy or fuel.
Does the Diacarbon process require more energy or fuel than it produces?
No. Although at start-up the system does require the input of fuel (propane) in order to reach the required temperature, going forward the system then becomes self-sustained by using the syn-gas by-product to power the process. Most of the chemical energy from the original biomass is contained in the biocoal or biochar products that are produced through our Diacarbon process. We have designed our system in such a manner that in the unlikely event if the process did required more energy than that already contained within our products, then all of the products and the additional propane would be consumed by the system.
Does the Diacarbon process produce greenhouse gases?
Yes. As propane and syn-gas are used to provide the heat for pyrolysis, carbon dioxide and other emissions which are released during the Diacarbon process. However, these emissions are far below the allowable limits and are minute when compared to the many tons of carbon we can remove from the atmosphere in the form of biochar or by replacing some fossil fuels with biocoal. As our pyrolysis products are derived from biomass these are carbon-neutral.
How can the Diacarbon process be used for carbon neutral or carbon negative applications?
Essentially all of the carbon content of biomass is derived from carbon dioxide in the atmosphere and when biomass decomposes this carbon returns to the atmosphere – this natural carbon cycle is carbon-neutral. Using biocoal as fuel also releases carbon dioxide. However, the carbon dioxide released by burning biocoal is equivalent to that which would be released by the decomposition of the starting biomass (albeit over a shorter period of time compared to natural decomposition). This is different than the carbon dioxide released by the burning of fossil fuels, which not part of the normal carbon cycle.
The Diacarbon process also produces biochar – a very stable form of carbon. This biochar can be safely buried and used as a soil amendment. Using the carbon in this way prevents it from being reused in biomass growth and results in a net decrease in carbon dioxide levels in the atmosphere (carbon-negative). As biochar is very stable it remains in the soil for thousands of years, leading to a long term reduction of atmospheric carbon dioxide.
What is biocoal?
Biocoal is a form of charcoal that is produced by pyrolysis at lower temperatures (around 290oC) and is dark brown in appearance. Biocoal differs from the starting biomass in that all moisture has been removed and it has increased energy density. In addition, the properties of biocoal are very much like fossil coal. This allows coal users to adopt bio-coal without the need to change their process handling. Biocoal is also a carbon-neutral fuel since it is derived directly from biomass.
What is biochar?
Biochar is a form of charcoal that is produced via pyrolysis. Like charcoal, it is a lightweight black substance comprising carbon and ash (inorganic metal-based compounds). The amount of carbon and ash in biochar varies depending on the type of biomass used. For example, certain types of wood produce biochar that is almost completely made of carbon, while manure biomass produces biochar that contains a large percentage of ash.
What can biochar be used for?
Biochar can be added to soil to improve water and nutrient retention which is very beneficial for plant growth. Burying the biochar also removes it from the natural carbon cycle and reduces the amount of carbon dioxide in the atmosphere.
Biochar can also be pressed into pellets or briquettes for use as a renewable fuel and a coal replacement. Unlike coal, which releases carbon dioxide and a variety of toxic emissions, biochar is very clean burning and releases primarily carbon dioxide.
Since coal is a form of carbon, can it be used as a soil treatment like biochar?
No! Although biochar and coal are both forms of carbon and can share similar energy contents, coal contains materials that are toxic to plants and animals, and would be harmful if added to soil. Biochar made from clean feedstock such as wood, plant residues, or any other biomass that has not been treated with a chemical is perfect for adding to soil in gardens, nurseries, or even larger crop fields.
Is the Diacarbon process the solution to our planet’s current energy and climate issues?
No, not by itself. The Diacarbon process is an important part of the solution, but by itself it will not be sufficient. Our planet is facing serious issues in terms of increasing energy demands combined with a weakening environment, and unfortunately there is no magic bullet that can solve these issues. Tapping into biomass reserves as means of replacing our decreasing supplies of fossil fuels is critical, as is using biochar as a form of capturing and reducing greenhouse gases, but this is not enough. Other organizations and industries are needed to manage our biomass sources, to replant our forests and protect our agricultural assets. Everyone is part of the solution and Diacarbon is committed to playing its part.
Will the increase in use of pyrolysis to convert biomass into fuel promote future clear cutting of forests or converting food crops into biomass-only crops?
Diacarbon is committed to only utilizing waste materials that result from other industries or processes. Unlike first generation ethanol production that depends largely on corn from our food supply, Diacarbon utilizes a conversion process that can use different forms of feedstock waste, and thus will have access to biomass simply from waste streams (such as crop waste, manure, wood and pulp waste, and pine-beetle wood).
That being said, increased clear cutting of forests and an increase in biomass-only crops are very real risks that exist even without the use of pyrolysis. Our demand for energy is increasing while our supplies are decreasing. Heavy use of forests for fuel, biomass crops for ethanol production, increased land use for oil, and coal exploration are all possible consequences of our future energy demands regardless of what energy technology we develop. In order to achieve true sustainability, we will need to greatly decrease our energy demands, implement aggressive measures to reuse and recycle our waste, and implement systems to manage our biomass and agricultural assets.