By Bilyamin Abdulmumin
A couple of days ago, the Lagos State government officially entered into an agreement with the Netherlands government to establish a waste-to-energy firm.
The initiative was said to get rid of heaps of waste across the Lagos metropolitan area (about 2250 tons daily) and generate between 60 and 75 megawatts of electricity annually, providing some 40,000 homes.
In addition, the Lagos State Governor Sanwo-Olu said the project will help cut down the country’s carbon footprint, as about 550,000 metric tons of carbon dioxide and other greenhouse gasses emitted daily from the dumpsite will be addressed.
Singapore is one of the countries that is an embodiment of waste to energy. Singapore is said to have zero waste, thanks to its waste-to-wealth program. They completely convert their waste, partly into energy and other parts into recycling.
Trust developed nations; they always think ahead. In Denmark, an innovative twist was added to this technology. Due to the extensive space occupied by the conversion centre, the top area of this facility would be transformed into a game reserve and tourist attraction. Who said you can’t kill two birds with one stone?
As Sanwo-Olu highlighted, the world is currently grappling with climate change, so several countries have been resorting to generating energy from biomass. This includes food crops (maize, sugarcane, cassava, etc.), lignocellulosic materials (e.g., woods), and waste (a mixture of biomass, petroleum products, and metals), the latest being the most expensive for conversion. By using waste to generate energy, countries would not only clean the environment but also cut down their carbon budget, hence mitigating the effect of the looming climate change.
The most widely used technology for waste-to-electricity conversion is the combustion integration into steam turbines. In this process, the waste is burned in the boiler unit to generate steam, which generates steam channels to power the turbine and the movement of turbine generic electricity. But that is not all; the exhaust steam is channelled into a condenser unit, where the steam is converted back to the water, then finally the water is pumped to the boiler to complete the cycle.
Applications of the laws of thermodynamics in each unit allow the energy usage analyses to make each step more efficient, that is, reduce energy waste in each section (boiler, turbine condenser, and pump). This technology is known as a steam turbine, one of the heat engines based on the principle of the Rankine cycle. A closely related heat engine is a locomotive rail or refrigeration and Air conditioning system based on Rankine cycles.
The second way to convert waste to energy is pyrolysis. In pyrolysis, waste is converted to oil instead of directly burning them. As mentioned above, these oils can then be burned in a boiler to generate steam and the cycle proceeds. Catalysts like zeolite can be used to upgrade the oil for use, such as petroleum. The difference between pyrolysis and combustion is that in the former, oxygen is not allowed; in fact, pyrolysis means a lack of oxygen. In the former, oxygen is necessary; without oxygen, combustion will not occur, or there will be incomplete combustion if it is inadequate.
The last category of technology for waste conversion is gasification; in this process, waste is converted to carbon monoxide and hydrogen (syngas); these gasses can be burned in a boiler to generate steam, and the process proceeds just as mentioned. Similarly, the syngas can be upgraded to synthetic fuels using metal catalysts like iron through popular technology known as Fischer-Tropsch. Depending on the quality, synthetic fuels produced may be used as petroleum, too. Gasification differs in combustion in the oxygen usage; in the former, oxygen is meticulously controlled.
Wise students will check out abundant videos on YouTube demonstrating these three categories of biomass conversion: combustion, pyrolysis, and gasification, the principles of Steam Turbines, Heat Engines, the Rankine cycle, and the Carnot Cycle, the applications of the laws of thermodynamics, and the catalysis involved in the bio-oil upgrade and the Fischer-Tropsch process.
If you are in the secondary or early years of a degree program and already aware of this information, then you are a step ahead, and you are not only fortunate than your peers but most of us at your level.
Bilyamin Abdulmumin wrote via bilal4riid13@gmail.com.