ENERGY FROM BANANA PEEL
Peels of various fruits and vegetables are commonly considered waste products and are thrown away. Some may be used as fertilizer, but most are left to rot.
Banana( Musa paradisiaca), a globally known fruit is rich in nutrients and has a lot of health benefits. The peels are usually discarded, however, different studies conducted on peels revealed the presence of important constituents that could be repurposed.
Many types of research are being conducted to reduce the usage of non-renewable fossil fuels. Due to the demand for electricity in industries, global warming and the increase in carbon dioxide levels, an alternate source of energy is required, preferably renewable sources.
| MFCs or Microbial Fuel Cells are capable of producing respiring electric current from respiring cells. |
If MFCs produce electricity on a large scale, this solution could benefit the environment. Another such benefit is producing energy from bananas.
A research group working at the Swiss Federal Institute of Technology conducted experiments on banana peel, orange peel, and coconut shells. Their version of the banana split involved the splitting of biomass, by flashes of light emanating from a xenon lamp.
APPEAL OF HYDROGEN:
- Before looking at this innovative approach, it is necessary to know that hydrogen is an attractive energy source.
- Hydrogen has an impressive energy storage capacity.
- While classifying fuels in terms of their energy value/heating value, the deciding elements are carbon, hydrogen and oxygen.
- Hydrogen has an energy level that is seven times that of carbon.
- Burning of hydrogen gives us only water and heat.
- A smarter way to harness the energy in hydrogen is to get electricity with it.
- This is achieved in a proton exchange membrane fuel cell where, in the presence of a metal catalyst, a hydrogen molecule is split into protons and electrons, with the electrons providing the current output.
TRANSPORT VEHICLES:
Unlike electric cars, hydrogen-powered cars have a refuelling time of only about 5 minutes. Commercially available hydrogen-powered cars have fuel tanks that can carry 5-6kg of compressed hydrogen, with each kilo providing a range of about 100km and emitting 9 litres of water as steam.
The limited popularity of hydrogen as a fuel is due to production and distribution restraints. It is safer than domestic cooking gas.
Industrial-level quantities of hydrogen gas are used in processes such as the production of ammonia for fertilizers.90% of the world's hydrogen is produced from fossil fuels.
Biomass is a catch-all term for organic waste material of plant and animal origin. It is a rich source of both hydrogen and carbon.
| Dried banana peel has 5% hydrogen and 33% carbon. |
An important goal of all climate change-curbing protocols is to sequester as much carbon as possible, not letting it become a gas.
PROCESS:
- The Swiss group used pyrolysis, where the organic matter is decomposed using small bursts of intense heat under inert conditions.
- Flashes of irradiation from a xenon lamp provide heat.
- A total of 15 milliseconds of irradiation are enough to heat the system to 600 degrees Celsius and decompose a kilogram of banana peel powder, liberating 100 litres of hydrogen gas.
- This short burst of photothermal energy also produces 330 grams of biochar, a solid residue that is rich in carbon.
It has to be noted here that, if the biomass is burnt, gaseous carbon would have escaped as carbon monoxide and carbon dioxide. But Pyrolysis ensures that carbon remains sequestered as solid.
BENEFITS OF BIOCHAR
- Apart from safekeeping carbon, biochar has several uses in agriculture.
- Agricultural leftovers like husk are a major source of biomass, and the biochar it forms has significant mineral content, adding enrichment to plant nutrients.
- The porous nature of biochar makes it suitable for remediation, and adsorption of toxic substances in polluted soils, thus reducing the potency of contaminants in soil.
- Biomass, be it from banana peel or tree bark or poultry manure, improves the air quality and adds value to agricultural produce.
