Selection, development and design of a continuous and intensified reactor technology to transform waste cooking oil in biodiesel and biosourced formulations

摘要

The objective of this thesis is to propose a continuous and intensified reactor to transform waste cooking oil into products that will be used in applications in the building and public works sector. This work is part of the FUI AGRIBTP, a collaborative research project whose finality is to the creation of an industrial tool for the reuse of co-products from agroindustries. The reactor must be able to handle transesterification and esterification (with methanol or with glycerol) reactions efficiently with a total flow rate of 100 kg/h. To achieve this objective, a literature review has identified a list of suitable reactor technologies for these reactions. The comparative analysis of these different technologies has led to the selection of three types of intensified reactors microstructured reactors (Corning® type), microwave reactors and oscillatory baffled reactors (NiTech® type). The performance of these reactors for transesterification and esterification reactions has then been investigated experimentally. High conversions have been obtained for transesterification and esterification with methanol reactions, thereby showing the improved performance of these intensified reactors compared with conventional reactors; however results obtained with esterification with glycerol reaction are still rather low due to limitations in operating temperature. Concerning the microwave reactor, the excellent results previously reported in the literature should be taken with care because of the inaccuracy of temperature measurements, as proven in this work. The oscillatory baffled reactor technology has been selected has the most industrially viable equipment for the considered reactions. The flexibility of this reactor, the independency of the flow rate and mixing, as well as the diameter ,which is large enough to avoid fouling caused by the quality of the feed line, are the main reasons for this choice. The commercial available system, built in glass, has nevertheless shown limitations in terms of operating temperature and pressure. As a result, further work has focused on reactor operation in a wider range of operating conditions. To do this, a collaboration with the TNO laboratory in Delft, Netherlands, was set up in order to investigate reaction performance an oscillatory baffled reactor made of stainless steel. The reaction performance obtained for esterification with glycerol is more than satisfactory, being significantly greater that that obtained in the glass Nitech reactor and even of higher quality compared to that obtained with a oscillatory helicoidal tubular reactor. In parallel to these studies, CFD simulations of flow in the reactor have enable the investigation of new baffle designs, which play a major role in the capacity to generation liquid-liquid dispersions of the immiscible reactants and in the quality of the mixing. These simulations have been compared with velocity measurements and flow patterns obtained in a transparent experimental rig using Particle Image Velocimetry. Finally, the results obtained on the pilot-scale rigs have been used to size a the oscillatory flow reactor for a total flow rate of 100 kg/h, which would be dedicated to the selective production of monoglycerides by esterification with glycerol reaction and also biodiesel production by transesterification reaction.