Developing a model for waste plastic biofuels in CRDi diesel engines using FTIR, GCMS, and WASPAS synchronisations for engine analysis
Authors: Kanchan Sumit , Pradhan Swastik , Kumar Rajeev , Sharma Shubham , Bhandari Omang , Priyadarshini Manisha , Dwivedi Shashi Prakash , Awwad Fuad A. , Khan M. Ijaz , Ismail Emad A. A. , Dhiman Renu 
Published: December 2023

The excessive use of single-use plastic products in modern life has caused severe environmental, social, economic, and health consequences globally. Mostly all plastics manufactured are one-time-use materials that end up in landfills or as unmanageable garbage. This situation has led to the production of around 400 million tonnes of plastic waste per year, and if this trend continues, global production will reach up to 1100 million tonnes by 2050. India alone produced over 34.7 lakh tonnes per annum (TPA) of plastic waste, with only half of it being recycled or co-processed. As such, there is an urgent need to develop ways to reduce plastic waste. One possible solution is the use of waste plastic biofuel in engines, which has been shown to have promising results. The study aimed to analyse waste plastic oil using (Gas Chromatography Mass Spectrometry) GC-MS and (Fourier Transform Infrared Spectroscopy) FTIR analysis to identify its chemical composition. The findings of the study revealed the presence of various chemical compounds, such as alcohol, hydroperoxide, carbonyl acid groups, ester, carboxylic acid, ketones, aldehyde groups, and others. FTIR analysis confirmed the presence of alcohol, hydroperoxide, carbonyl acid groups, methyl and methylene groups, ester, carboxylic acid, ketones, aldehyde group, symmetric and asymmetric C-H bending, C-O stretch for ethers, carboxylic acids, and esters, and=C-H bending out for alkenes. The study further explains that primary plastic consumption and packaging lifetime have a significant impact on plastic waste generation. The research indicates the need to explore alternative ways to recycle and dispose of single-use plastics to mitigate its negative impact on the environment. Furthermore, this study analyses the statistical optimisation method to develop a model fit for engine behaviour using waste plastic biofuel on a single-cylinder (common rail direct injection engine) CRDi diesel engine using the (weighted aggregated sum product assessment) WASPAS approach. Additionally, the objective is to develop a model that can optimise the engine's performance while using waste plastic biofuel. The uncertainty analysis demonstrated that the experiment was carried out with a high degree of accuracy and the results were reliable. The study employed the WASPAS methodology to evaluate the performance of different (waste plastic oil) WPO samples, and the results showed that the optimal parametric setting to obtain the desired responses can be achieved with a fuel blend of 5%, load of 21 bar, and speed of 2000 RPM. However, the results demonstrate that the use of waste plastic biofuel can significantly improve engine performance, and the proposed optimisation model can accurately predict the engine's behaviour. The regression equation that was formulated showed a reasonable degree of agreement between the actual experimental results and the predicted values, thereby indicating the reliability of the experiment. Significant effects were observed from fuel blend, and speed, whereas load did not make a substantial contribution. The findings regarding the effect of parameters suggest that a reduction in fuel blend, and engine speed resulted in a decline in the performance index, while variations in load had little impact. The relationship between load and speed demonstrates that a rise in load and a reduction in speed contributed to enhanced combustion and a higher performance index. The interaction among fuel blend and speed, with a particular emphasis on the significance of reduced fuel blend and speed values in order to optimise the performance index. The findings of the analysis underlined the vitality of process parameters, specifically fuel blend and speed, wherein speed exhibited a significant impact on the outcomes. The study concludes that the use of waste plastic biofuel in engines can be an effective way to reduce plastic waste while improving engine performance. This study's findings can be applied to various engines to improve their performance while reducing plastic waste. All in all, the outcomes of the study make a substantial contribution to the advancement of scientific information regarding the properties of waste plastic oil as well as its combustion characteristics. This expands the potential for advanced breakthrough innovations in sustainable energy solutions and the conservation of the environment.