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| Author(s): |
Letícia Arthus
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química |
| Defense date: | 2025-03-18 |
| Examining board members: |
Leonardo Vasconcelos Fregolente;
Ana Rita Morales;
Sonia Maria Alves Bueno;
João Batista de Paiva Soares;
Fauze Ahmad Aouada
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| Advisor: | Maria Regina Wolf Maciel; Leonardo Vasconcelos Fregolente |
| Abstract | |
The water content is one of the key quality parameters in the specifications for biodiesel and diesel. Currently, in Brazil, the maximum allowable water content is 250 ppm for diesel and 350 ppm for biodiesel, while the European Union sets limits at 200 ppm and 500 ppm, respectively. Water levels exceeding 800 ppm have been observed in biodiesel storage tanks in Brazil, raising concerns about fuel quality, especially with the increasing blending of biodiesel into commercial diesel. High water levels in fuels can cause mechanical failures and impair vehicle performance. Given the need for an efficient technology capable of removing both free and dissolved water with versatile applications, polymeric hydrogels have been investigated. This thesis proposes the development of packed beds filled with synthetic hydrogels grafted onto cellulose materials for water removal from biodiesel and its blends with diesel. The study assesses the influence of cellulose presence, alkaline hydrolysis, and drying methods on the performance of hydrogels, which must combine mechanical robustness, high hydrophilicity, fast water removal kinetics, and suitable geometry for continuous processes. In batch processes, the incorporation of cellulose microfibrils (MFC) maintained the hydrogel's efficiency, removing 49% of water from the saturated biodiesel, achieving performance comparable to salt beds and heating while increasing compressive strength by fivefold. Additionally, hydrolysis and lyophilization treatment increased the water removal capacity of biodiesel by 165% with 30 minutes of contact. In fixed-bed columns, hydrolyzed composite hydrogels (PAM/MFC-Hd), shaped into Raschig rings, reduced the water content from 952.8 ppm to 463.6 ppm (51% removal) after 2.3 hours of contact, meeting EN 14214 standards. These hydrogels maintained their performance over seven consecutive cycles of operation, including four cycles with regenerated material. In series with a column of hydrolyzed and lyophilized hydrogels, the final water content was reduced to approximately 350 ppm. Additionally, the non-hydrolyzed composite hydrogel removed 40% of water from biodiesel in 2.3 hours. For B15 diesel (15% v/v biodiesel), the same material reduced water content by 36% in 17 minutes, reaching levels below 200 ppm. Furthermore, the treated fuels maintained quality within analyzed parameters. Compared to other anionic hydrogels with similar performance, the PAM/MFC-Hd composite hydrogel presented costs 17% and 50% lower than sodium acrylate copolymer and sodium polyacrylate hydrogel, respectively. This research addresses the challenges of using hydrogels in industrial applications, offering economic, durability, reusability, and compliance advantages with fuel quality standards (AU) | |
| FAPESP's process: | 21/08438-1 - Development of beds of hidrogel grafted with cellulose nanomaterials obtained by additive manufacturing for removal of water from biodiesel and diesel |
| Grantee: | Letícia Arthus |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |