Naslov sklopa raziskovalnih podatkov / doktorskega dela : raziskovalni podatki, obravnavani v doktorskem delu

Zamljen, Aleksandra (author)

Integracija sinteze amonijaka s separacijo na osnovi trdnih sorbentov predstavlja učinkovito pot za izboljšanje učinkovitosti procesa, saj omogoča kontinuirno odstranjevanje amonijaka in s tem izboljšanje učinkovitosti procesa. Med sorbenti so še posebej zanimivi kovinski halogenidi, zaradi možnosti reverzibilne tvorbe aminskih kompleksov z visoko kapaciteto za amonijak in odlično selektivnostjo pri procesno relevantnih pogojih, čeprav njihova močna afiniteta do vlage in omejena ciklična stabilnost ostajata ključni izziv za praktično uporabo. Disertacija obravnava na nosilcih podprte sorbente na osnovi kovinskih halogenidov za visokotemperaturno separacijo amonijaka, s poudarkom na identifikaciji ključnih dejavnikov, ki določajo sorpcijsko kapaciteto, stabilnost in reakcijske mehanizme. Cilj dela je bil pojasniti razmerje med strukturo in lastnostmi materialov, s pomočjo obsežne karakterizacije in kinetičnega modeliranja. Sistematična analiza vpliva lastnosti nosilcev na sorpcijsko kapaciteto materialov na osnovi MgCl2, impregniranih na porozne nosilce, je pokazala, da je sorpcijska kapaciteta močno odvisna od procesnih pogojev, kislosti nosilca in strukture por, pri čemer sta 50 ut% MgCl2/ZSM 5 (30) in 50 ut% MgCl2/USY (500) izkazala najvišjo kapaciteto za amonijak. Stabilnost in mehanizem deaktivacije 50 ut% MgCl2/USY (500) sorbenta sta bila preučena v prisotnosti vlage ter pri cikličnem obratovanju v suhih pogojih. Izpostavljenost vlagi je povzročila znatno zmanjšanje kapacitete, ki ga ni preprečila niti predhodna vezava amonijaka. Pri cikličnem obratovanju je ponavljajoče se raztezanje in krčenje kristalne mreže med tvorbo aminskih kompleksov povzročilo nastanek strukturnih sprememb, kar je privedlo do zmanjšanja sorpcijske kapacitete. Ovrednotili smo tudi vpliv kovinskega kationa (Mg, Ca, Sr) in nanosa soli v na ZSM-5 (1500) podprtih kovinskih halidih na sorpcijsko kapaciteto za amonijak pri visoki temperaturi. MgCl2 je izkazal najboljše delovanje zaradi višje gostote naboja Mg2+ in pri 300 °C in 0.8 bar parcialnega tlaka amonijaka obdržal kapaciteto 1 molNH3/molsoli. Mikrokinetični model je uspešno reproduciral prebojne in desorpcijske krivulje in omogočil vpogled v stopenjsko tvorbo in razgradnjo aminskih kompleksov. Razviti sorbent je bil ovrednoten v magnetno ogrevanem sistemu za sintezo in separacijo amonijaka, kar je potrdilo njegovo uporabnost pod reprezentativnimi obratovalnimi pogoji.

• Language: Slovenian
• Keywords: separacija amonijaka, kovinski halogenidi na nosilcih, zelena energija, študija sorpcije, kinetično modeliranje
• Work type: Research data
• Typology: 2.20 - Research data
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2026
• PID: 20.500.12556/RUL-190106
• Data col. methods: Measurements and tests
• Publication date in RUL: 22.10.2026

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: English
• Title: Title of the research dataset / doctoral dissertation : research data underlying the doctoral dissertation

Abstract

Integrating ammonia synthesis with solid sorbent based ammonia separation offers an effective route for process intensification by continuously removing ammonia and enhancing efficiency. Among sorbents, metal halides are particularly attractive because they reversibly form ammine complexes with high ammonia capacity and excellent selectivity under process relevant conditions, although their strong affinity for moisture and limited cyclic stability remain major challenges for practical implementation. This dissertation investigates supported metal halide sorbents for high temperature ammonia separation, with an emphasis on identifying the key factors governing sorption performance, stability, and sorption mechanisms. The work aims to elucidate structure property relationships through comprehensive experimental characterization complemented by a kinetic model. A systematic evaluation of the influence of support properties on the ammonia sorption performance of MgCl2 impregnated porous supports showed that sorption capacities depend strongly on operating conditions, support acidity, and pore architecture, with 50wt% MgCl2/ZSM 5 (30) and 50wt% MgCl2/USY (500) exhibiting the highest ammonia uptake. The stability and deactivation mechanisms of 50wt% MgCl2/USY (500) were further investigated under humid air and dry cycling conditions. Moisture exposure resulted in significant capacity loss, which could not be prevented by pre ammoniation, while repeated lattice expansion and contraction during ammine complex formation induced structural changes that gradually reduced sorption capacity. The influence of metal cation (Mg, Ca, Sr) and salt loading in ZSM-5 (1500)-supported metal halides on the high temperature ammonia sorption behaviour was evaluated. MgCl2 demonstrated superior performance due to the higher charge density of Mg2+, retaining an uptake of approximately 1 molNH3/molsalt at 300 °C and 0.8 bar ammonia partial pressure. A microkinetic model accurately reproduced the experimental breakthrough and desorption profiles, providing mechanistic insight into the stepwise formation and decomposition of ammine complexes. Finally, developed sorbent was evaluated in a magnetic heated ammonia synthesis separation system, demonstrating its applicability under representative operating conditions.

• Keywords: ammonia separation, supported metal halides, green energy, sorption study, kinetic modelling

Projects

• Funder: Other - Other funder or multiple funders