A mobile pyrolysis unit for carbon sequestration and fertilizer production
WHAT IS THE CHALLENGE?The increased temperature the last half a century around the globe and the risk of unpredictable drastic climate changes is most probably caused by human activities, mainly burning of fossil fuels, which has markedly increased the atmospheric concentration of carbon dioxide (CO2). Carbon dioxide Cap and Storage (CCS) is being developed at certain fossil fuel fired power and heat generation plants. This to reduce the amount of CO2 reaching the atmosphere. However, these techniques cannot reduce the CO2 content in the atmosphere. In addition, these techniques are energy demanding and costly. The present efforts to markedly increase burning of straw, branches and other organic waste in agriculture and forestry in order to use energy from a CO2 neutral source will deplete the amount of organic matter in soil. This will result in increased leakage of nutrients and vulnerability to droughts, poorer soil structure and expected reduced yields in the future. HOW CAN THE PROJECT CONTRIBUTE TO A SOLUTION?The aim of the proposed project is to develop a mobile pyrolysis unit for production of biochar from waste organic material. By incorporating the biochar into soil, soil fertility and water holding capacity are improved and nutrient leaching reduced. Since biochar is stable in soil for thousands of years, the increasing CO2 levels in air may be mitigated. The concept is based on an innovative combination of several established techniques and the soil product, Terra Preta, was produced by Indians in the Amazon already many thousand years ago. The concept is highly competitive from both economic and energy aspects for mitigating high air CO2 levels.The aim is threefold: I.) mitigating high air CO2 levels; II.) improve soil fertility; III.) deliver energy to the agriculture and raw materials to the synthetic industry. The ”heart” of the project is a ”charvester”, a mobile unit for pyrolysis (that is heating at restricted oxygen supply) of organic waste material in a closed system. Gases produced such as hydrogen, carbon oxide and methane will be collected and serve in the chemical industry as an energy source. The fraction remaining, about 30 % of the original biomass, will be elementary carbon or biochar. This is an excellent soil conditioner. The advantage of leaving part of the organic fraction behind as non-degradable biochar is an approach needed to achieve a sustainable society in its true meaning for future generations
WHO WILL BENEFIT FROM THE RESULTS?
Depending on perspective, there are several levels of beneficiaries, while nobody will experience disadvantages. In a broad context, humanity will profit from reduced levels of CO2 in the atmosphere and thereby a more stable and predictable climate. In order to get the technique spread globally at large scale, funds are needed to be built up on carbon taxation. Subsidies will then be granted those who sequester biochar as a long term carbon sequestration means. It should be observed that biochar, once spread into soil, cannot be recovered and its content of CO2 cannot intentionally be released as is the case if logging forests, initially intended to be a carbon source.
In the perspective of supplying raw materials, feed and food, everybody engaged in cultivation may profit from the technique because the fertility and productivity of soil will increase when applying biochar. The charvester of the project will permit the technique to be spread to a larger group of cultivating people, both as a commercially available machine and as a seed of idea, spreading the knowledge into other groups than those where the charvester is operating. Such examples are home gardeners, who with a less sophisticated pyrolysing unit may transform garden waste into a soil improver in their garden.
