Frequently Asked Questions
General 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 300°C in the absence of oxygen. Pyrolysis yields products in three phases of matter: a gas phase (synthesis-gas), a liquid phase (bio-oil), and a solid phase composed primarily of carbon (biochar).
Different amounts of the three product phases can by produced by varying the conditions of pyrolysis. Higher temperatures (above 600°C) and faster heating tends to favour synthesis-gas and bio-oil production. Lower temperatures (300-600°C) and slower heating increases the amount of biochar produced. The Diacarbon process operates in the lower temperature range in order to maximize the production of biochar.
Because the products of pyrolysis have not reacted with oxygen, they can be utilized easily for other applications, such as fuels, industrial chemical compounds, soil amendments, and carbon capture and storage.
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 (i.e. materials are burned). During combustion, materials react with the oxygen as they burn. There are many everyday examples of this, such campfires, candles, and the burning of gasoline inside a car engine. Unlike pyrolysis, the primary products of combustion are carbon dioxide and ash; these have completely reacted with oxygen, and in general can not 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. Once the pyrolysis in underway the heat can be maintained by using a portion of the syn-gas produced by the process. As such, the process is self-sustained (does not require the input of external energy or fuel).
Technology
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, the system is then self-sustained by using a portion of the syn-gas product to power the process. Most of the chemical energy from the original biomass is contained within the bio-oil and biochar that is produced by the Diacarbon process. If the process required more energy than was contained within the products, all of the products and the additional propane would be consumed by the system, which is not the case.
Does the Diacarbon process produce greenhouse gases?
Yes, because propane and syn-gas are used to provide the heat for pyrolysis, carbon dioxide and other emissions 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 bio-oil or syn-gas.
How can the Diacarbon process be used for 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 biomass as fuel also releases carbon dioxide (albeit over a shorter period of time compared to natural decomposition). However, the Diacarbon process produces biochar, which is a very stable form of carbon. This char 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).
Products
What is bio-oil?
Bio-oil is the liquid product that is obtained from pyrolysis of biomass. The 'oil' is a very complex mix of chemicals, and the actual composition depends on the type of feedstock used. In general, bio-oil is a thick brown liquid that has a distinct smoky smell.
What can bio-oil be used for?
The most immediate application for bio-oil is as a fuel, and with minimal treatment can be used directly as a replacement for diesel in some stationary power generators, boilers and process heaters. However, many fuel applications (such as transportation) require more refined fuels, and in these cases the bio-oil must be upgraded and purified before it can be used. Diacarbon is investigating several ways of upgrading the oil for such applications.
Bio-oil can also be used as a source of chemicals that are valuable in various industrial applications, such as flavorings in food and as pharmaceutical drug precursors.
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.
Sustainability and the Environment
Is the Diacarbon process the solution to our planetŐs 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 and a weakening environment, and unfortunately there is no magic bullet that can solve these issues. Tapping into biomass reserves as a way of replacing our dwindling supplies of fossil fuels is critical, as is using biochar as a way of capturing and reducing greenhouse gases, but they are 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.
Is it true that biochar can be used to capture carbon from the atmosphere?
Yes. Plants take in carbon dioxide to produce biomass as they grow. When this biomass is converted into biochar, the carbon that originated from carbon dioxide is converted into a very stable form of carbon that is more resistant to environmental degradation. Biochar can be added to soil to prevent the carbon from returning to the atmosphere. If used on a larger scale with biomass wastes, millions of tons of carbon could potentially be captured from the atmosphere. This could contribute to reducing the effects of greenhouse gas accumulation.
How does biochar in soil benefit plant growth?
The specific biological and chemical benefits of biochar to plants are active areas of research, but most evidence suggests that biochar can help retain both nutrients and water when mixed with soil. Soil treated with biochar is more resistant to leeching (loss of nutrients) and dehydration. This means that plants have access to a more consistent supply of water and nutrients in the soil.
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