Pyrolysis

The European Bioenergy Research Institute at Aston University (EBRI) has developeda unique process for upgrading biomass and ash rich residues from agriculture and forestry to heat, power, oil and fertilizer. The topic regenerative energy with the main pillar biomass is established as a high priority topic of the UK. Pyrolysis is an attractive option for pre-treatment and pre-conditioning. Pyrolysis converts the feedstock to gases, pyrolysis oils and char. This way it is possible to realize chemical products out of the liquid fractions and to separate or remove process influencing components like ash in the char. It is known, that pyrolysis is used for the production of fuels directly usable for CHP firing. Examples are the Pytec process from Bremerhaven (Germany) and the Haloclean® process from Karlsruhe (Germany) and Turin (Italy). The feed herby is wood or rape seed. France and the United-Kingdom currently favor in their research programmes the direct use of pyrolysis liquids in petro refineries. Hereby the oils have to be converted to fit to the petro chemical belongings. The removal of oxygen can be carried out via catalysts. The studies and reviews of UK´s Carbon Trust have shown the options also in the same way the difficulties which have to be solved to reach a sustainable concept. All in all one has to mention that neither the fertilizer loop is closed nor an optimal integration of the products gas and char is shown.

The core process of the project is a Pyroformer using intermediate pyrolysis technique. Intermediate pyrolysis is a special kind of pyrolysis and is a cutting edge technology working in contrast to the existing slow and fast pyrolysis techniques. The reaction temperature for this process is typically around 450 to 500 deg C with a very less vapor residence time in the order of few seconds. The solids residence time can be varied as desired. The reaction occurs under controlled heating rates thereby avoiding the tar formation. Another distinct advantage with the Intermediate Pyrolysis is that no pre-treatment of the feedstock is required and the feed can be in any form and size ranging from powder to chips as well. The products from this kind of pyrolysis can be directly applied for CHP purposes and have already been proven. The patented process can be used for different kinds of biogenic feedstock such as algae, residues from biogas plants, energy grass, wood residues and other residues from agriculture and forestry into pyrolysis liquid, pyrolysis gas and pyrolysis char with typical ratio of 20 to 30 wt % of char and 15 to 25 wt % of gas. The total pyrolysis vapours (about 60-75% of the energy of the input material) now low in ash are directly passed to a gasifier and gasified.