Researchers have developed an energy-efficient method for converting bio-waste into hydrogen and fertiliser
Spotted: Researchers are working on several ways to reduce our consumption of fossil fuels. One alternate source of energy is hydrogen produced from organic waste, or biomass. While the use of biomass can help reduce CO2 emissions, there are still questions about the best way to maximise the conversion of biomass to energy. Two main methods currently in use are gasification and pyrolysis. Gasification burns biomass at high temperatures to produce ‘syngas’ biofuel and a solid waste product – biochar.
Pyrolysis is similar, but uses lower temperatures and higher pressures. One method, flash pyrolysis, is the fastest and produces the most syngas, but is also needs specialised reactors. Now, scientists at Switzerland’s EPLF have developed a new method for pyrolysis that produces both syngas, and a useful, solid-carbon biochar. The new method uses a xenon lamp as a source of high-power energy. The biomass absorbs the energy and this triggers conversion into syngas and biochar.
The EPLF researchers used the technique on materials such as banana peels, corn cobs, orange peels, coffee beans and coconut shells. These were dried and ground to a powder, which was exposed to the xenon flashes. Each kilogramme of biomass powder generated 100 litres of hydrogen and 330 grammes of biochar, which is a very good return. The flash pyrolysis takes just milliseconds.
In addition to the speed of this process, both the end products, hydrogen and solid-carbon biochar, are valuable. The hydrogen can be used as green fuel, while the carbon biochar can be used as a fertiliser and in the manufacture of conductive electrodes. Researcher Bhawna Nagar adds that the relevance of the work “is further heightened by the fact that we are indirectly capturing CO2 stores from the atmosphere for years. We have converted that into useful end products in no time using a Xenon flash lamp.”
While the EPLF researchers are working on the efficiencies of large-scale fuel production from biowaste, others are working on smaller-scale projects that are no less innovative. At Springwise, we have covered a number of these projects, large and small, including a toilet that turns human waste into energy and a small-scale biowaste processor that produces both liquid fuel and compost.
Written By: Lisa Magloff