| Popis: |
Proizvodnja biodizela, neotrovnog kapljevitog goriva koje svoju sve širu primjenu pronalazi kao zamjena ili dodatak dizelu fosilnog podrijetla, u zadnje vrijeme privlači sve veću pozornost. Jedan od najpoznatijih i najznačajnijih reakcijskih puteva sinteze biodizela, reakcija transesterifikacije, predmet je brojnih istraživanja pa je tako analizirana i u okviru ovog rada. Kao jedan od novih reaktorskih sustava za proizvodnju biodizela transesterifikacijom sve veći interes i primjenu pronalaze mikroreaktori. Za provedbu reakcije transesterifikacije u mikroreaktorima, kao i u ostalim reakcijskim sustavima, potrebno je odrediti optimalne reakcijske uvjete potrebne kako bi se dobili iskorištenja te udjeli metilnih estera masnih kiselina u skladu s odgovarajućim standardima. Kao polazna sirovina u proizvodnji biodizela najčešće se koriste različita ulja i masti prirodnog podrijetla, a kao rezultat procesa transesterifikacije dobiva se produkt koji sadrži komponente koje je potrebno odvojiti kako bi se dobio biodizel čistoće u skladu s odgovarajućim standardima. U okviru ovog rada, a u svrhu proizvodnje biodizela koji zadovoljava standarde, razvijen je integrirani mikrosustav u kojemu je prvo provedena reakcija transesterifikacije u mikroreaktoru, a zatim pročišćavanje biodizela u serijski povezanom mikrosustavu. Pročišćavanje je provedeno u mikroekstraktoru s niskotemperaturnim eutektičkim otapalom koje iz biodizela uklanja zaostale reaktante i dobiveni glicerol pri čemu se dobiva biodizel visoke čistoće. Enzim lipaza, koji je korišten za provedbu reakcije transesterifikacije u mikroreaktoru, imobiliziran je na magnetske nanočestice što je omogućilo njegovo zadržavanje u mikroreaktoru i posljedično olakšalo proces pročišćavanja biodizela u serijski povezanom mikrosustavu te proces učinilo ekonomski opravdanim. Inaktivacija enzima metanolom, drugim reaktantom u procesu transesterifikacije koji se u pravilu dodaje u suvišku, jedan je od osnovnih izazova provedbe procesa transesterifikacije katalizirane enzimima. Kao jedno od procesnih rješenja ovog izazova primijenjen je mikroreaktorski sustav u kojemu su kao ulazne procesne struje korišteni čisti metanol te emulzija ulja i enzima pri čemu je proizveden biodizel uz iskorištenje od 94 % uz vrijeme zadržavanja, 𝜏 = 20 min. Dodatno je razvijen i integrirani sustav spajanjem mikroreaktora s mikroekstraktorom pri čemu je proizveden biodizel uz iskorištenje od 94 % za vrijeme zadržavanja, 𝜏 = 20 min, te uz udio glicerola od 0,019 % (w/w). The production of biodiesel, a non-toxic liquid fuel that has been increasingly used as a replacement or addition to diesel of fossil origin, has recently attracted an increasing attention. One of the best known and most important reaction pathways of biodiesel synthesis, the transesterification reaction, is the subject of numerous studies and was analyzed in this paper. As one of the new reactor systems for biodiesel production by transesterification, microreactors have increased interest and application. To demonstrate transerterification reaction in microreactors, as well as in other reaction systems, it is necessary to determine the optimal reaction conditions needed in order to obtain yields and content of fatty acid methyl esters in accordance with relevant standards. As a starting material in the production of biodiesel, various oils and fats of natural origin are commonly used, and as a result of the transesterification process, a product is obtained that contains components that need to be separated in order to obtain the purity of biodiesel in accordance with relevant standards. Purpose of this work was biodiesel production of purity defined by relevant quality standards. An integrated microsystem was developed in which the transesterification reaction was firstly carried out in the microreactor leading to the purification of biodiesel in a microsystem connected in series. Purification was performed in a microextractor using a deep eutectic solvent that removes residual reactants and produced glycerol where in the same time biodiesel of high purity is obtained. Lipase, which was used to carry out the transesterification reaction was immobilized on magnetic nanoparticles, which enabled enzyme retention in a microreactor and consequently facilitated the process of purification of biodiesel integrated microsystem and made the process economically sustainable. Inactivation of the enzyme by methanol, another reactant in the transesterification process which is generally added in excess, is one of the primary challenges of enzyme-catalyzed transesterification processes. As one of the possible process solutions, a microreactor system was used in which pure methanol and emulsion of oil and enzyme were used as process inlets where biodiesel was produced with a yield of 94 % for the retention time of 𝜏 = 20 min. Additionally, an integrated system was developed by combining the microreactor with a microextractor. In this system biodiesel was produced with a yield of 94 % for the retention time of 𝜏 = 20 min, and with glycerol content of 0,019 % (w/w). |
