Combustion, performance and emission analysis of a DI diesel engine using plastic pyrolysis oil

Plastic waste is an ideal source of energy due to its high heating value and abundance. It can be converted into oil through the pyrolysis process and utilised in internal combustion engines to produce power and heat. In the present work, plastic pyrolysis oil is manufactured via a fast pyrolysis process using a feedstock consisting of different types of plastic. The oil was analysed and it was found that its properties are similar to diesel fuel. The plastic pyrolysis oil was tested on a four-cylinder direct injection diesel engine running at various blends of plastic pyrolysis oil and diesel fuel from 0% to 100% at different engine loads from 25% to 100%. The engine combustion characteristics, performance and exhaust emissions were analysed and compared with diesel fuel operation. The results showed that the engine is able to run on plastic pyrolysis oil at high loads presenting similar performance to diesel while at lower loads the longer ignition delay period causes stability issues. The brake thermal efficiency for plastic pyrolysis oil at full load was slightly lower than diesel, but NOX emissions were considerably higher. The results suggested that the plastic pyrolysis oil is a promising alternative fuel for certain engine application at certain operation conditions

Pyrolysis of waste plastics and utilisation of the produced oils in diesel engines.

An experimental investigation was conducted to study the conversion of waste plastics and single polymers into high quality oils through the pyrolysis process at elevated temperatures that haven’t been investigated before. Furthermore, the utilisation of the produced pure oils in a diesel engine for power generation was explored, which is a novelty of this research. In addition, a longevity test was carried out in the diesel engine with a high blend of pyrolysis oil to diesel in order to understand the long-term effects of the oil in the engine performance characteristics and components. In order to improve the engine’s performance and increase the operational life of the engine, different approaches (such as the injection timing modification and fuel additive addition) were studied. Another novelty of this research is the investigation of the macroscopic spray characteristics of the plastics pyrolysis oil in a constant volume vessel. The effect of the pyrolysis temperature on the produced yields and oils quality was also explored for a mixture of plastics and different pure polymers (such as styrene butadiene, polyethylene terephthalate, ethylene-vinyl acetate, polyethylene and polypropylene) separately. An important finding of this research is that the pyrolysis of polyethylene terephthalate at high temperatures results in the production of only gas and char (no liquid) and pyrolysis plant failures. Finally, the best pyrolysis oil quality and diesel engine performance were acquired from the oil that was produced from the pyrolysis of low density polyethylene, while the rest of the oils produced from the pyrolysis of ethylene-vinyl acetate and polypropylene generated acceptable diesel engine performances

Influence of advanced injection timing and fuel additive on combustion, performance and emission characteristics of a DI diesel engine running on plastic pyrolysis oil

This paper presents the investigation of engine optimisation when plastic pyrolysis oil (PPO) is used as the primary fuel of a direct injection diesel engine. Our previous investigation revealed that PPO is a promising fuel however the results suggested that control parameters should be optimised in order to obtain a better engine performance. In the present work, the injection timing was advanced, and fuel additives were utilised to overcome the issues experienced in the previous work. In addition, spray characteristics of PPO were investigated in comparison with diesel to provide in-depth understanding of the engine behaviour. The experimental results on advanced injection timing (AIT) showed a reduced brake thermal efficiency and increased carbon monoxide, unburned hydrocarbons and nitrogen oxides emissions in comparison to standard injection timing. On the other hand, the addition of fuel additive resulted in a higher engine efficiency and lower exhaust emissions. Finally, the spray tests revealed that the spray tip penetration for PPO is faster than diesel. The results suggested that AIT is not a preferable option while fuel additive is a promising solution for long-term use of PPO in diesel engines

Experimental evaluation of a diesel engine fuelled by pyrolysis oils produced from low-density polyethylene and ethylene-vinyl acetate plastics

Depletion of oil resources and increase in energy demand have driven the researchers to seek ways to convert the waste products into high quality oils that could replace fossil fuels. Plastic waste is in abundance and can be converted into high quality oil through the pyrolysis process. In this study, pyrolysis oils were produced from polyethylene (LDPE700), the most common used plastic, and ethylene-vinyl acetate (EVA900) at pyrolysis temperatures of 700oC and 900oC respectively. The oils were then tested in a four cylinder diesel engine, and the performance, combustion and emission characteristics were analysed in comparison with mineral diesel. It was found that the engine could operate on both oils without the addition of diesel. LDPE700 exhibited almost identical combustion characteristics and brake thermal e ciency to that of diesel operation, with lower NOX, CO and CO2 emissions but higher unburned hydrocarbons (UHC). On the contrary, EVA900 presented longer ignition delay period, lower e ciency (1.5–2%), higher NOX and UHC emissions and lower CO and CO2 in comparison to diesel. The addition of diesel to the EVA900 did not significantly improve the overall engine performance

Experimental evaluation of a diesel engine fuelled by pyrolysis oils produced from low-density polyethylene and ethylene-vinyl acetate plastics

Depletion of oil resources and increase in energy demand have driven the researchers to seek ways to convert the waste products into high quality oils that could replace fossil fuels. Plastic waste is in abundance and can be converted into high quality oil through the pyrolysis process. In this study, pyrolysis oils were produced from polyethylene (LDPE700), the most common used plastic, and ethylene-vinyl acetate (EVA900) at pyrolysis temperatures of 700oC and 900oC respectively. The oils were then tested in a four cylinder diesel engine, and the performance, combustion and emission characteristics were analysed in comparison with mineral diesel. It was found that the engine could operate on both oils without the addition of diesel. LDPE700 exhibited almost identical combustion characteristics and brake thermal e ciency to that of diesel operation, with lower NOX, CO and CO2 emissions but higher unburned hydrocarbons (UHC). On the contrary, EVA900 presented longer ignition delay period, lower e ciency (1.5–2%), higher NOX and UHC emissions and lower CO and CO2 in comparison to diesel. The addition of diesel to the EVA900 did not significantly improve the overall engine performance

The utilisation of oils produced from plastic waste at different pyrolysis temperatures in a DI diesel engine

Chemical recycling is an attractive way to address the explosive growth of plastic waste and disposal problems. Pyrolysis is a chemical recycling process that can convert plastics into high quality oil, which can then be utilised in internal combustion engines for power and heat generation. The aim of the present work is to evaluate the potential of using oils that have been derived from the pyrolysis of plastics at di erent temperatures in diesel engines. The produced oils were analysed and found to have similar properties to diesel fuel. The plastic pyrolysis oils were then tested in a four-cylinder direct injection diesel engine, and their combustion, performance and emission characteristics analysed and compared to mineral diesel. The engine was found to perform better on the pyrolysis oils at higher loads. The pyrolysis temperature had a signi cant e ect, as the oil produced at a lower temperature presented higher brake thermal e ciency and shorter ignition delay period at all loads. This oil also produced lower NOX, UHC, CO and CO2 emissions than the oil produced at a higher temperature, although diesel emissions were lower