1. Integration of an absorption chiller to a process applying the pinch analysis approachAndreja Nemet, Zdravko Kravanja, Miloš Bogataj, 2022, original scientific article Abstract: In addition to the consumption of hot utilities, there is also a significant cost associated
with the consumption of cold utilities when there is a high demand for cooling. A promising
solution for cooling is an absorption chiller (AC), which uses heat instead of electricity for cooling.
A thermodynamic approach for evaluating AC integrated with a process is presented in this work.
A model for assessing the properties and duties of an AC cycle was developed. The integration of
a combined process-AC system was evaluated using the Grand Composite Curve. Three different
options of integration were analyzed: (i) above the Pinch, (ii) below the Pinch, and (iii) across the
Pinch. AC represents the combined effect of a heat engine and a heat pump, as the generator together
with the absorber and condenser has the function of a heat engine, while the evaporator combined
with the absorber and condenser mimics the function of a heat pump. The comparison between the
non-integrated and integrated process-AC systems has revealed that the proper placement of AC is
across or below the Pinch and the improper is above the Pinch. If AC was entirely integrated below
the Pinch, the integration would result in a complete (100%) reduction in the consumption of hot
utility for the operation of AC. The most suitable placement of AC with double reduction of hot
utility consumption and complete reduction of both hot and cold utility to operate AC is across the
Pinch due to the pumping of heat through AC from below to above the Pinch.
Keywords: absorption chiller, Pinch analysis, heat integration, low-temperature heat
Published in DKUM: 15.05.2025; Views: 0; Downloads: 0
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2. Ocena potenciala medsektorske integracije v Sloveniji s poudarkom vključevanja prometnega sektorja : zaključno poročiloAndreja Nemet, Miloš Bogataj, David Hvalec, Franco Krog, Klemen Rola, Sven Gruber, Jurij Avsec, Danijela Urbancl, Darko Goričanec, Zdravko Kravanja, 2025, final research report Keywords: medsektorska integracija, prometni sektor
Published in DKUM: 03.04.2025; Views: 0; Downloads: 5
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3. 7th International Conference on Technologies & Business Models for Circular Economy : Conference Proceedings2025, proceedings Abstract: The 7th International Conference on Technologies & Business Models for Circular Economy (TBMCE) was organized by the Faculty of Chemistry and Chemical Engineering of the University of Maribor in collaboration with the Strategic Research and Innovation Partnership – Networks for the transition into circular economy (SRIP – Circular economy), managed by the Chamber of Commerce and Industry of the Štajerska. The event took place from September 4 to 6, 2024 in Portorož, Slovenia, at the Grand Hotel Bernardin. The conference focused on the current challenges and opportunities related to technological development and society's responsibility in the transition to a more sustainable and circular management of resources. The conference program included a round table on "Circular Economy Transition in the South-East Europe", 5 panel discussions, plenary and 2 keynote speeches as well as oral and poster presentations. The conference was held under the patronage of the Ministry of the Economy, Tourism and Sport and the Ministry of Cohesion and Regional Development. EIT RawMaterials RIS Hub Adria, SPIRIT Slovenia Business Development Agency, and Pomurje Technology Park (as part of the GREENE 4.0 and CI-Hub projects) joined us as co-organizers.
Keywords: circular economy, sustainable development, processes and technologies, circular business models, research and development
Published in DKUM: 03.03.2025; Views: 0; Downloads: 6
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4. Methanol production via power-to-liquids : a comparative simulation of two pathways using green hydrogen and captured CO2David Tian Hren, Miloš Bogataj, Andreja Nemet, 2024, original scientific article Abstract: Methanol is a versatile substance that can be used in combustion engines and fuel cells and as a feedstock for the production of various chemicals. However, the majority of methanol is currently produced from fossil fuels, which is not sustainable. The aim of this study was to analyze and evaluate the feasibility of methanol production from renewable sources as a bridge to a low-carbon economy and its potential as an alternative to fossil-derived chemicals. For this purpose, the process of methanol production from captured CO2 and water as an H2 source was simulated in Aspen Plus. For CO2 capture, the monoethanolamine (MEA) absorption process was assumed. The H2 required for methanol synthesis was obtained by alkaline water electrolysis using electricity from renewable sources. The captured CO2 and the produced H2 were then converted into methanol through the process of CO2 hydrogenation in two ways, direct and two-step synthesis. In the direct conversion, the hydrogenation of CO2 to methanol was carried out in a single step. In the two-step conversion, the CO2 was first partly converted to CO by the reverse water-gas shift (RWGS) reaction, and then the mixture of CO and CO2 was hydrogenated to methanol. The results show that direct synthesis has a higher methanol yield (0.331 kmol of methanol/kmol of H2 ) compared to two-step synthesis (0.326 kmol of methanol/kmol of H2 ). The direct synthesis produces 13.4 kmol of methanol/MW, while the two-step synthesis produces 11.2 kmol of methanol/MW. This difference amounts to 2.2 kmol of methanol/MW, which corresponds to a saving of 0.127 $/kmol of methanol. Besides the lesser energy requirements, the direct synthesis process also produces lower carbon emissions (22,728 kg/h) as compared to the two-step synthesis process (33,367 kg/h).
Keywords: power-to-X, Aspen Plus, methanol, CO2 capture, methanol production, water electrolysis
Published in DKUM: 12.02.2025; Views: 0; Downloads: 8
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5. Optimiranje odstranjevanja formaldehida iz azeotropne zmesi butanol/isobutanol/formaldehid/metanol/voda s pretvorbo v heksametilentetraminJan Hartl, 2024, undergraduate thesis Abstract: Namen diplomske naloge je bil preučiti izvedljivost odstranjevanja formaldehida iz azeotropne zmesi butanol/isobutanol/formaldehid/metanol/voda s pretvorbo formaldehida v heksametilentetramin (HMTA).
V sklopu eksperimentalnega dela smo izvedli eksperimente v skladu s centralno kompozitnim eksperimentalnim načrtom in razvili statistično relevanten linearni model, ki opisuje odvisnost masnega deleža formaldehida v raztopini v odvisnosti od dodane množine metanola in amonijaka. Z razvitim modelom smo optimirali reakcijske pogoje s ciljem minimiranja deleža formaldehida in preostalega amonijaka v raztopini. Model potrjuje hipotezo, da je prisotnost metanola problematična, saj stabilizira formaldehid (pretvorba formaldehida ob prisotnosti metanola v hemiacetal) in ga tako naredi manj dostopnega za pretvorbo v HMTA. Po pričakovanjih pa višanje množine amonijaka kot reaktanta zmanjšuje delež preostalega formaldehida.
Rezultati kažejo, da je na laboratorijski ravni odstranjevanje formaldehida iz azeotropne zmesi s pretvorbo v HMTA izvedljivo. Kot eno izmed možnih tehnologij za ločevanje HMTA iz raztopine smo uporabili vakuumsko destilacijo, s katero HMTA odstranimo kot destilacijski ostanek. Pri pogojih, ki smo jih določili kot optimalne, se je masni delež formaldehida v raztopini znižal iz začetnih 1,39 % na 0,048 %.
Keywords: odstranjevanje formaldehida, heksametilentetramin, azeotropne zmesi, vakuumska destilacija, načrtovanje eksperimentov, optimiranje reakcijskih pogojev.
Published in DKUM: 19.09.2024; Views: 0; Downloads: 21
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6. Kompenzatorji mrtvega časa regulacija procesov z dolgim mrtvim časom : diplomsko delo univerzitetnega študijskega programa I. stopnjeBlaž Vidovič, 2024, undergraduate thesis Abstract: Namen diplomske naloge je bil ugotoviti vpliv različno dolgih mrtvih časov na regulacijo procesov 1. in 2. reda. Mrtvi čas, v dinamičnih sistemih, predstavlja časovni zamik med dejansko spremembo vhodnega signala in spremembo izhodne spremenljivke, ki je posledica časa, potrebnega za prenos informacije skozi sistem. V delu smo izvedli simulacije v računalniškem orodju Simulink, za servo in regulacijske probleme. Izvedli smo tudi regulacijske simulacije sistema z motnjo šuma. Primerjali smo učinkovitost regulacije sistema, reguliranega z navadno PID povratnozančno shemo, s shemo regulirano s Smithovim prediktorjem.
Rezultati kažejo, da je Smithov prediktor primernejša rešitev za regulacijo sistemov z dolgim mrtvim časom tako v pri sledenju referenčne vrednosti, kot tudi v primeru regulacijskih problemov in regulacijskih problemov z dodano motnjo šuma, saj z njim dosežemo manjše oscilacije in hitrejšo vzpostavitev stacionarnega stanja. Iz rezultatov je razvidno tudi, da so regulacijske sheme v sistemih z mrtvim časom učinkovitejše pri blaženju nizkofrekvenčnega šuma kot visoko frekvenčnega šuma.
Keywords: regulacija procesov, PID regulator, Smithov prediktor, mrtvi čas, Simulink
Published in DKUM: 09.09.2024; Views: 40; Downloads: 41
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7. 7th International Conference on Technologies & Business Models for Circular Economy : book of abstracts2024 Abstract: The 7th International Conference on Technologies & Business Models for Circular Economy (TBMCE) was organized by the Faculty of Chemistry and Chemical Engineering, University of Maribor in collaboration with the Strategic Research and Innovation Partnership - Networks for the Transition into Circular Economy (SRIP- Circular Economy), managed by the Chamber of Commerce and Industry of Štajerska. The conference was held in Portorož, Slovenia, at the Grand Hotel Bernardin from September 4th to September 6th, 2024. EIT RawMaterials RIS Hub Adria, SPIRIT Slovenia Business Development Agency and Pomurje Technology Park (as part of the GREENE 4.0 and CI-Hub projects) have joined us as co-organizers. TBMCE 2024 was devoted to presentations of circular economy concepts, technologies and methodologies that contribute to the shift of business entities and society as a whole to a more responsible, circular management of resources. The conference program included panel discussions, plenary and keynote sessions, oral and poster presentations on the following topics: Sustainable Energy, Biomass and Alternative Raw Materials, Circular Business Models, Secondary Raw Materials and Functional Materials, ICT in Circular Economy, Processes and Technologies. Panel discussions addressed following topics: Circular Economy Transition in South East Europe, The transition to carbon neutrality in energy intensive industry, Valorization of used and contaminated wood, Circular economy trends in construction, Critical raw materials and circular economy transition, Industrial Symbiosis and its opportunities for industry, AI and circular economy. The event was under the patronage of Ministry of the Economy, Tourism and Sport and Ministry of Cohesion and Regional Development.
Keywords: circular economy, sustainable development, processes and technologies, circular business models, research and development
Published in DKUM: 22.08.2024; Views: 93; Downloads: 26
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8. Proizvodnja metanola iz ogljikovega dioksida - primerjava dveh sinteznih potiDavid Tian Hren, 2024, master's thesis Abstract: Ogljikov dioksid (CO2) je glavni toplogredni plin, ki prispeva h globalnemu segrevanju. Pretvorba emisij CO2 v tekoča goriva, kot je metanol, je obetavna tehnologija za zmanjšanje emisij ogljika in proizvodnjo uporabnih goriv. Metanol je vsestransko gorivo, ki se lahko uporablja v motorjih z notranjim zgorevanjem, gorivnih celicah in kot surovina za proizvodnjo različnih kemikalij. Vendar pa se večina metanola trenutno proizvaja iz fosilnih goriv, kar ni trajnostno. Sinteza metanola iz CO2 prek fotokatalitskih, elektrokemičnih in kemičnih metod ponuja potencialno rešitev za trajnostno proizvodnjo metanola in zmanjšanje emisij CO2.
Cilj magistrskega dela je bil v programu Aspen Plus izvesti simulacijo procesa proizvodnje metanola iz ogljikovega dioksida in vode kot vira vodika. Za zajem CO2 smo uporabili postopek absorpcije z monoetanolaminom (MEA), ki je široko uporabljana tehnologija za zajemanje CO2 iz industrijskih dimnih plinov. Nato smo vodik, potreben za sintezo metanola, pridobivali z alkalno elektrolizo vode, ki je ena najstarejših in najbolj razširjenih metod za proizvodnjo vodika iz obnovljivih virov. Zajeti ogljikov dioksid in proizvedeni vodik smo nato na dva načina pretvorili v metanol s postopkom hidrogeniranja CO2, in sicer z direktno in dvostopenjsko sintezo. Pri direktni pretvorbi smo izvedli neposredno hidrogeniranje CO2 v metanol. Pri dvostopenjski pretvorbi pa smo CO2 najprej pretvorili v CO z reakcijo RWGS, nato pa smo mešanico CO in CO2 hidrogenirali v metanol. Poleg simulacije procesa smo izvedli tudi analizo porabe pogonskih sredstev ter njunih stroškov ter občutljivostno analizo glede na temperaturo v reaktorju in vhodni tok vodika.
Rezultati kažejo, da ima direktna sinteza večji donos metanola (63,56 t/h) v primerjavi z dvostopenjsko sintezo (62,70 t/h), vendar le za 1,4 %. Direktna sinteza porabi 147,9 MW energije, medtem ko dvostopenjska sinteza porabi 175 MW. Ta razlika znaša 15,5 % oziroma 27,1 MW, kar pomeni letni prihranek v višini 2,2 milijona dolarjev.
Keywords: moč-do-X, Aspen Plus, metanol, zajemanje CO2, proizvodnja metanola, elektroliza vode
Published in DKUM: 05.08.2024; Views: 101; Downloads: 46
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9. 6th International Conference on Technologies & Business Models for Circular Economy : conference proceedings2024, proceedings Abstract: The 6th International Conference on Technologies & Business Models for Circular Economy (TBMCE) was organized by the Faculty of Chemistry and Chemical Engineering of the University of Maribor in cooperation with Strategic Research and Innovation Partnership – Networks for the transition into circular economy (SRIP – Circular economy), managed by the Chamber of Commerce and Industry of the Štajerska. The conference was held in Portorož, Slovenia, at the Grand Hotel Bernardin from September 6th to September 8th, 2023. TBMCE 2023 was devoted to presentations of circular economy concepts, technologies and methodologies that contribute to the shift of business entities and society as a whole to a more responsible, circular management of resources. The conference program included a round table Standardization for circular economy – more secure and less complicated closing of material loops, 6 panel discussions, 1 plenary and 3 keynote lectures, oral and poster presentations. The event was under the patronage of Ministry of the Economy, Tourism and Sport and Ministry of Cohesion and Regional Development. The Netherlands joined us as a partner country.
Keywords: sircular economy, sustainable development, processes and technologies, circular business models, research and development
Published in DKUM: 26.02.2024; Views: 646; Downloads: 584
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10. Transitioning towards Net-Zero Emissions in Chemical and Process Industries : a holistic perspectivePeter Glavič, Zorka Novak-Pintarič, Helena Levičnik, Vesna Dragojlović, Miloš Bogataj, 2023, review article Abstract: Given the urgency to combat climate change and ensure environmental sustainability, this review examines the transition to net-zero emissions in chemical and process industries. It addresses the core areas of carbon emissions reduction, efficient energy use, and sustainable practices. What is new, however, is that it focuses on cutting-edge technologies such as biomass utilization, biotechnology applications, and waste management strategies that are key drivers of this transition. In particular, the study addresses the unique challenges faced by industries such as cement manufacturing and highlights the need for innovative solutions to effectively reduce their carbon footprint. In particular, the role of hydrogen as a clean fuel is at the heart of revolutionizing the chemical and process sectors, pointing the way to cleaner and greener operations. In addition, the manuscript explores the immense importance of the European Green Deal and the Sustainable Development Goals (SDGs) for the chemical industry. These initiatives provide a clear roadmap and framework for advancing sustainability, driving innovation, and reducing the industry's environmental impact, and are a notable contribution to the existing body of knowledge. Ultimately, alignment with the European Green Deal and the SDGs can bring numerous benefits to the chemical industry, increasing its competitiveness, promoting societal well-being, and supporting cross-sector collaboration to achieve shared sustainability goals. By highlighting the novelty of integrating cutting-edge technologies, addressing unique industrial challenges, and positioning global initiatives, this report offers valuable insights to guide the chemical and process industries on their transformative path to a sustainable future.
Keywords: net zero, energy, process industries, emissions, climate, chemicals, biomass, waste, cement, metals
Published in DKUM: 19.02.2024; Views: 333; Downloads: 553
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