MEASUREMENT OF CARBONYL EMISSIONS FROM EXHAUST OF ENGINES FUELLED USING BIODIESEL-ETHANOL-DIESEL BLEND AND DEVELOPMENT OF A CATALYTIC CONVERTER FOR THEIR MITIGATION ALONG WITH CO, HC’S AND NOX.

The research work is divided into (1) a portable sample collection technique (2) developing a suitable catalyst combination and (3) manufacturing a catalytic converter with novel design. Taking into account the hazards of aldehydes in ambient air, and carbonyl emissions compounds, an effort has been made to investigate the carbonyl compounds and measure their concentrations for diesel engines using Bio Ethanol (BE)-diesel fuel. From the said analysis, development of a potential catalytic converter is envisioned in order to reduce these emissions along with carbon monoxides, hydrocarbons and nitrogen oxides. Catalytic converter is specially manufactured for reduction of carbonyl emissions from the BE-diesel fuelled engine and its comparison and its integration with conventional three way catalysts is discussed. The retention time of the raw sample peak is comparable to the retention time of formaldehyde standard solution. Solitary formaldehyde peak is obtained. Peaks of acetaldehyde and acetone are not obtained due to their lower concentrations than the limit of detection, at the given loading condition. Retention time of each arrangement is close to that of formaldehyde standard. It is observed that CO, HC and NOx conversion efficiencies remained constant irrespective of combination with specially designed ZrO2 catalyst. Formaldehyde concentration obtained for one ZrO2 catalyst sample is significantly lower than raw emissions. Added ZrO2 catalyst showed further reduction. Thus, with optimum loading and surface area improvement methods, better results are achievable. Pt-Rh catalyst shows better carbonyl reduction than Pd-Rh catalyst. However, each of the three way catalysts is less efficient than ZrO2 catalyst. ZrO2 catalyst used in series with Pt-Rh catalyst shows the highest percentage reduction in formaldehyde concentration. Pt-Rh catalyst pair is effective in CO mitigation than Pd-Rh pair. The percentage reduction for HC and NOx is comparable for both. Pt-Rh also depicts better carbonyl reduction ability. ZrO2 is a better choice than noble metals in terms of availability and cost. Moreover it features a selective nature towards oxidation of aldehydes. Thus, Pt-Rh in combination with ZrO2 becomes technologically effective and economically viable choice.