Preparation of novel composite polyHIPE polymers and their applications in intensified removal of tars from syngas

Abstract

In this study, several techniques were applied in order to produce PolyHIPE Polymer (PHP) with improved morphology and properties. Several types of PolyHIPE Polymers (PHPs), silica, vinyl trimethoxy silane (VTMS), and VTMS-silica PHPs, were successfully produced and compared to basic PHPs. The VTMS-silica PHP produced has the highest surface area, followed by silica-PHP and then by VTMS- PHP when compared to typical (basic) PHP. For VTMS PHP, only PHPs with 30, 35 and 40% VTMS exhibit higher surface area than basic PHP. There was no improvement of surface area for PHP with VTMS percentage lower than 30%. All VTMS-silica PHPs have higher pore volume of all types of modified PHPs. The highest pore volume was observed for S30B30, the PHP with 30% VTMS in the oil phase and 30% silica in the aqueous phase. VTMS PHPs with VTMS percentage of 20% and above and silica PHP with 30 % silica have significantly higher pore volume than basic PHP. None of the PHPs showed the existence of micropore volume. Silica and VTMS were successfully reinforced into the HIPE producing novel PHP. This was confirmed by the results produced through FTIR spectroscopy and EDX (Energy Dispersive X-Ray) analysis. Novelty was observed in the morphology of VTMS and VTMS-silica PHP whereas silica-PHP retained the typical morphology of PolyHIPE polymer. The novel morphology of banana-like strands with coral-like pore was produced due to functionalising of VTMS to the HIPE through VTMS incorporation in the oil phase. VTMS-silica PHP is best described as having morphology of knobbly structure produced through incorporation of silica CC30 solution through aqueous phase with VTMS through oil phase. Sulphonated silica-PHP was successfully produced through microwave irradiation and thermal treatment whereas sulphonated-VTMS PHP was successfully produced through thermal treatment only. The sulphonation process decreased the surface area of silica and VTMS PHPs significantly. There was no significant difference between the pore volumes of silica PHPs and those of sulphonated silica PHPs whereas pore volumes of VTMS PHPs decreased significantly due to sulphonation. The sulphonation process retained the morphology of silica and VTMS PHPs except for minor cracks. The project also involved a study on tar removal/conversion using the modified PHP developed in the laboratory, high voltage and non-thermal plasma technique, specifically dielectric barrier discharge. The PHPs combined with dielectric barrier discharge was applied in the fine cleaning system. Due to complexity of the crude oil used as the tar model, no valid conclusion could be made about the tar removal or conversion. However, important positive effects from the treatment were observed in the removal of model tar from the model syngas under electric field or non-thermal plasma.