Evaluation of different natural ingredients as satiety inductors

Dissertation to obtain a Master’s Degree in Chemical and Biochemical Engineering

Valorization of agroindustrial waste

The main objective of this work is the valorization of residues from agro-industry giving them an added value. The valorization was performed by using a "green" and sustainable solvent - supercritical fluid, in this case carbon dioxide. Two residues and one biomass were used to produce two different final products, thereby emphasizing the versatility of the waste recovery - spent coffee grounds and microalgae Chlorella protothecoides to produce biodiesel, and tomato pomace to extract carotenoids. In the first part of this work it was demonstrated the possibility to obtain a conversion of coffee spent grounds oil into biodiesel, through an enzymatic transesterification reaction, of 98.01% with the following operating conditions: molar ratio oil:methanol 1:24, residence time 0.8 min, pressure 25 MPa, temperature 313,15K. In this first phase, it was also used the microalgae Chlorella protothecoides, a biomass, to produce biodiesel and favorable results were obtained with this green process compared with a traditional process - basic catalysis / acid. In the second part of this work, by an extraction with supercritical CO2 it was obtained 3.38% oil from tomato pomace under the following conditions: pressure 35.1 MPa, temperature 313,15K. It was found that this oil contains various carotenoids: β-carotene, lutein and lycopene. The latter is present in larger amount.

Fuel switching

The present Master dissertation is a project whose main objective is to identify value creation opportunities through fuel switching in the Portuguese industry, services, agriculture and fishing sectors. Fuel switching opportunities are characterized by type of fuel transition, type of technology transition, economy subsectors prone to have fuel switching and value created through fuel shift. Results suggest tomato concentrate, dairy, beer manufacturing and sugar refining subsectors is where prevalence of fuel oil steam boilers is high, for such cases conversion to natural gas steam boilers should result in operations having a ratio of NPV over CAPEX larger than ten and a payback period just under one year. Results further suggest food, beverages, textile, chemicals and wood subsectors currently operate between ten and twenty cogeneration Diesel engines that can be either modified to operate with natural gas or replaced by new natural gas cogeneration systems. Financial modeling indicates that both options have great value creation potential. The current analysis aims to be used by natural gas suppliers and energy project promoters to identify new potential deals as well as by heavy energy consumers to mitigate their energy related costs.