In an article published in the journal Materials Today: Proceedings, the use of waste cooking oil (WCO) as biofuel combined with zinc oxide (ZnO), aluminum oxide (Al2O3), and graphene nanoparticles with clean diesel is investigated to increase engine efficiency while lowering the diesel motor emissions.
Study: Performance, combustion and emission characteristics of single cylinder CI engine with WCO biodiesel and nanoparticles. Image Credit: Scharfsinn/Shutterstock.com
The Problem with Fossil Fuels
Globally, more than 10 billion tons of fossil fuels are used each year. To meet growing demands, the use of fossil fuels is predicted to rise further in the near future.
The problem with using fossil fuels is that they emit harmful pollutants. The burning of fossil fuels primarily releases CO2, a major greenhouse gas among the principal causes of global warming.
Other pollutants, such as sulfur, carbon monoxide (CO), and nitrogen oxides (NOx), pose a significant danger to human health, contributing to severe asthma, poor cardiorespiratory fitness, chronic bronchitis, and cardiac problems.
Much research has investigated alternate fuels due to the increased requirement for reduced fuel usage and exhaust emissions. Efforts have also focussed on improving the engine's combustion efficiency while using standard gasoline.
What is Biodiesel?
Biodiesel is a clean alternative combustion fuel made from locally available, recyclable sources. The fuel is a blend of fatty acid alkyl esters derived from animal fats, vegetable oils, and reprocessed grease.
Biodiesel may be utilized directly in compression ignition (CI) engines without the need for any alterations. It is easy to use, renewable, biodegradable and contains no sulfur or aromatic hydrocarbons.
It is often utilized as a diesel fuel addition to lower the quantities of particulate matter, CO, aromatics, and toxins emitted by diesel-fueled cars.
Although recycled waste cooking oil (WCO) is harmful to health, disposing of leftover cooking oil is not eco-friendly. As a result, the ideal approach is to utilize it for industrial uses, such as converting it into biodiesel.
WCO is being utilized as feedstock to reduce biofuel prices. WCO biodiesel can lower the production cost of biodiesel since feedstock expenses account for roughly 70–95 percent of the total expense of biodiesel synthesis.
The injection of nanoparticles (NPs) into the fuel enhances its thermal conductivity. By enhancing the heat conductivity of the fuel, its burning is improved, and therefore the burning efficiency is increased.
As a result, the use of NPs will enhance biodiesel combustion efficiency in CI engines and boost engine performance. Furthermore, since NPs have a larger surface-to-volume ratio, improved burning may be performed in the combustion chamber.
Nanoscale additives also boost the ignition temperature, decrease the ignition time delay, and increase the biofuel's radiative mass transfer in the combustion zone. As a result of improved combustion, the use of NPs can minimize emissions in CI engines.
The team conducted the experiment on a single-cylinder, 4-stroke water-cooled, naturally aspirated, direct injection diesel engine. The engine had an 18:1 compression ratio and could produce 3500 W of power at a steady 1500 revolutions per minute, and fuels utilized in the tests were a combination of biodiesel and NPs.
First, the different physicochemical parameters of the mixed biodiesel were investigated and compared to those of clean diesel, which serves as a base fuel.
The experiment was then conducted at 1500 rpms and varied loads of 25%, 50%, 75%, and 100% of full load capacity for diesel fuel to examine the combustion performance and emission quality of the CI engine.
Various biofuels were also tested in the same CI engine to determine their combustion performance and emission quality. Finally, after assessment, the fuel mix was adjusted based on combustion performance and emission quality.
The study aimed to assess the combustion performance and emission characteristics of WCO-based biodiesel in a single cylinder CI engine with various NPs.
Compared to conventional diesel, biodiesel nanoparticle mixes showed a high brake thermal efficiency (BTE). Graphene and ZnO NP mixed biodiesel were found to yield outstanding BTE, and CO, HC, and NOx emission levels were reduced by including NPs into the mix
However, when compared to regular diesel, all of the NP blends and the B20 mix were found to emit more smoke.
Continue reading: Can Nanoparticle Fuel Additives Give Hope to Fossil Fuel Engines?
Nayak, V., Karthik, A., Sreejith, B., et al. (2021) Performance, combustion and emission characteristics of single-cylinder CI engine with WCO biodiesel and nanoparticles. Materials Today: Proceedings. Available at: https://www.sciencedirect.com/science/article/pii/S2214785321072746?via%3Dihub