In autothermal pyrolysis, only air is used as the fluidizing gas. As a result, the energy for pyrolysis is provided through partial oxidation of pyrolysis products within the reactor, thereby eliminating the heat transfer bottleneck of conventional pyrolysis.
Autothermal pyrolysis has four advantages:
- Simplified reactor design. Air-blown operation removes the need for external gas, and the design can be easily scaled up.
- Process intensification, which has the goal of increasing outputs of desired products with fewer inputs of chemicals, water, energy, labor, and/or capital and fewer outputs of wastes and pollutants. With autothermal pyrolysis with process intensification, the biomass feed rate can be almost five times higher than with conventional pyrolysis. Process intensification of pyrolysis makes possible the construction of smaller, modular systems suitable for distributed processing of dispersed biomass feedstocks.
- Higher yields of bio-oil, organics, and in particular, sugar. We have doubled sugar yields compared to conventional pyrolysis while increasing volumetric sugar production rates by 100 fold compared to enzymatic hydrolysis.
- Reduced capital costs of more than 25 percent, according to technoeconomic analysis.
We have modified our well-known pilot system to research autothermal pyrolysis. In this system, bio-oil is recovered in fractions, a patented BEI technology. The products include sugars for cellulosic ethanol and phenolic oils for production of bio-asphalt and diesel engine fuels. Autothermal pyrolysis also produces an excellent biochar, which can serve as a soil amendment and helps make the process carbon negative.
Autothermal pyrolysis also produces an excellent biochar, which can serve as a soil amendment and helps make the process carbon negative. The aqueous phase products can be converted to methane by anaerobic digestion.
BEI is working with private and public partners on demonstration-scale projects of the technology. This effort is being accelerated by the DOE-funded RAPID Institute, the country’s tenth Manufacturing USA initiative. The project includes design and testing of pyrolysis equipment as well as agronomic studies of biochar. We’re also analyzing life-cycle costs and the environmental impact.
Engineers developing tools to understand, scale up autothermal production of bio-oil (Iowa State news release)