1. Integration of an absorption chiller to a process applying the pinch analysis approachAndreja Nemet, Zdravko Kravanja, Miloš Bogataj, 2022, izvirni znanstveni članek Opis: 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.
Ključne besede: absorption chiller, Pinch analysis, heat integration, low-temperature heat
Objavljeno v DKUM: 15.05.2025; Ogledov: 0; Prenosov: 0
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2. Synthesis of Heat-Integrated Water Networks Using a Modified Heat Exchanger Network SuperstructureNidret Ibrić, Elvis Ahmetović, Andreja Nemet, Zdravko Kravanja, Ignacio E. Grossmann, 2022, izvirni znanstveni članek Ključne besede: water network, water integration, heat exchanger network, heat-integrated water network, superstructure optimisation
Objavljeno v DKUM: 14.02.2025; Ogledov: 0; Prenosov: 5
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3. Editorial: combined water and heat integration in the process industriesElvis Ahmetović, Ignacio E. Grossmann, Zdravko Kravanja, François Marechal, Jiri Klemeš, Luciana E. Savulescu, Dong Hongguang, 2022, predgovor, uvodnik, spremna beseda Opis: Water and energy are resources that are used in large quantities in different sectors (domestic, agricultural, and industrial). Based on data on global water and energy consumption in the world over the recent past, as well as forecasts for the coming years, a continuous trend of increasing water and energy consumption can be observed. ...
Ključne besede: water integration, heat integration, systematic methods, pinch analysis, mathematical programming, heat-integrated water networks, optimisation, process industry
Objavljeno v DKUM: 18.08.2023; Ogledov: 429; Prenosov: 34
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4. Synthesis of non-isothermal heat integrated water networks in chemical processesMiloš Bogataj, Miguel J. Bagajewicz, 2008, izvirni znanstveni članek Opis: This paper presents a new approach for the simultaneous synthesis and optimization of heat integrated water networks. A new superstructure for heat exchanger network (HEN) synthesis is proposed. The procedure is based on mixed integer non-linear mathematical programming (MINLP). Four relevant examples are presented to illustrate various aspects of the proposed approach.
Ključne besede: chemical processing, chemical process design, process water networks, water networks, wastewater minimization, heat integration, MINLP, HEN synthesis, superstructures, process synthesis
Objavljeno v DKUM: 31.05.2012; Ogledov: 2298; Prenosov: 100
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5. Heat integration between two biodiesel processes using a simple methodAnita Kovač Kralj, 2008, izvirni znanstveni članek Opis: Biodiesel is a clean-burning alternative fuel, produced from domestic, renewable resources. Biodiesel can be blended at any level with petroleum diesel to create a biodiesel blend. It can be used in compression-ignition (diesel) engines with little or no modification. Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics. This paper presents heat integration between two biodiesel processes. Biodiesel can be produced by the esterification of different fatty acids (high and low boiling point) with alcohols. This simple method for heat integration is based on three possible steps. Simultaneous integration between processes can be performed using a stagewise model with a mixed integer nonlinear programming (MINLP) algorithm (step 3), which can include alternatives suggested by pinch analysis of heat transfer between the processes (step 2). The internal integration of individual processes can be performed in step 1. The fraction can be calculated for maximum integration between processes. Integration between the processes can be carried out using all three steps or by the first and third steps or by the last step only, depending on the problems' complexities. This method includes streams of different processes which are heated or cooled using a utility only. The existing heaters and coolers can be left unchanged in their original processes or can be used for integrating heat between processes, with hot and cold utilities being saved. This approach is illustrated by integrating two simulated biodiesel processes.The objective was to maximize additional annual profit for integration between processes by USD8300/a.
Ključne besede: chemical processing, biodiesel producing, heat integration, nonlinear programming
Objavljeno v DKUM: 31.05.2012; Ogledov: 2168; Prenosov: 131
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6. H2 separation and use in fuel cells and CO2 separation and reuse as a reactant in the existing methanol processAnita Kovač Kralj, Peter Glavič, 2007, izvirni znanstveni članek Opis: Fuel-cell efficiencies yield substantial reductions in the emissions of climate-change gases and promise an end to exclusive reliance on carbon fuels for energy. Fuel cells, CO2 reuse, process heat integration, and open gas turbine electricity cogeneration can be optimized simultaneously, using a nonlinear programming (NLP) algorithm. The simplified NLP model contains equations of structural and parametric optimization. This NLP model is used tooptimize complex and energy-intensive continuous processes. This procedure does not guarantee a global cost optimum, but it does lead to good, perhaps near-optimum, designs. The plant, which produces methanol, has a surplus of hydrogen (H2) and CO2 flow rates in purge gas. H2 is separated from the purge gas by an existing pressure swing adsorption (PSA) column. Pure H2 can be usedas fuel in fuel cells. CO2 can be separated from the outlet stream (purge gas) by a membrane or absorption system (absorber and regenerator) or an adsorption system and reused as a reactant in a reactor system. Therefore, theproduct yield can be increased and CO2 emissions can be reduced, simultaneously. CO2 emissions can then be reduced at the source. The retrofitted process can be operated within existing parameters. Using a methanol process as a case study, the CO2 emission flow rate can be reduced by4800 t/a. The additional electricity cogeneration in the gas turbine and in fuel cells and additional flow rates of the raw material could generate an additional profit of 2.54 MEUR/a.
Ključne besede: chemical processing, methanol production, optimization, nonlinear programming, CO2 reuse, fuel cells, heat integration, energy cogeneration
Objavljeno v DKUM: 31.05.2012; Ogledov: 2763; Prenosov: 124
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7. Design of the optimal total site heat recovery system using SSSP approachAndreja Goršek, Peter Glavič, Miloš Bogataj, 2006, izvirni znanstveni članek Opis: Site expansions or changes in production capacities are usually related with changes of utilities demands andžor utility system design. Despite several available and well established techniques for process synthesis and integration, very often, changes in process designs are made on the basis of intuition and experiences of engineers. In this paper possibilities of rational energy consumption and energy integration in an existing site for production of specialty chemicals were studied. On the basis of real process parameters and computer simulation results energy integration was re-examined.Total site analysis using modified Site Sink Source Profiles, which gives a profound insight into the site utility system configuration, heating-cooling demands and cogeneration design was performed. The existing site was found to be very well designed. With only few modifications additional 9% of hot utilities and 5% of cold utilities savings are possible.
Ključne besede: chemical engineering, process design, optimization, heat integration, cogeneration, pinch method, energy retrofit
Objavljeno v DKUM: 30.05.2012; Ogledov: 3084; Prenosov: 101
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8. Heat integration in a speciality product processMajda Krajnc, Anita Kovač Kralj, Peter Glavič, 2006, izvirni znanstveni članek Opis: The essence of effective process designing is to use methods which are efficient to engineers in practice and not only to scientists. The proposed design procedure is composed of two steps: conceptual one and optimization one. At the conceptual step, pinch design analysis is used. In the optimization step pinch analysis and mixed-integer nonlinear programming method are applied. In the case study analysed, a speciality product is to beproduced in continuous chemical process with a capacity which causes smallerheat flow rates and needs smaller heat exchanger areas than usual. Therefore, an equation for cost estimation of heat exchangers with areas smaller than 7 m2 was developed and used in the optimization procedure. Using thermodynamic pinch analysis and mathematical programming method, the heat integrated structures were synthesized and compared with the base process flowsheet. Finally, the optimal structure was determined.
Ključne besede: načrtovanje procesov, načrtovanje procesov, ekonomska analiza, prenos toplote, optimizacija, chemical process design, economic analysis, heat integration, optimization
Objavljeno v DKUM: 30.05.2012; Ogledov: 2598; Prenosov: 80
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