Modeling and Energy Optimization of the Catalytic Naphtha Reforming Process

Proces katalitičkog reforminga benzina je jedan od glavnih procesa u industrijskoj preradi nafte, koristi se za proizvodnju visoko-oktanskih motornih benzina, kao i za proizvodnju sirovina za procese u petrohemijskoj industriji. U doktorskoj disertaciji razmatrani su tehnologija, matematičko modelovanje procesa, strategija energetske optimizacije i pravci budućeg razvoja procesa katalitičkog reforminga benzina. Za modelovanje procesa katalitičkog reforminga benzina uspostavljen je termodinamički model i razvijen je semi-empirijski pseudo-kinetički model. U cilju primene odgovarajućeg termodinamičkog modela ravnoteže para-tečnost testirano je nekoliko modela: Redlich-Kwong, Soave-Redlich-Kwong, Benedict-Webb-Rubin-Starling i Chao-Seader. Na bazi dobijenih rezultata utvrđeno je da je Soave-Redlich-Kwong-ov model najadekvatniji za modelovanje procesa katalitičkog reforminga benzina. U razvijenom kinetičkom modelu strategija grupisanja komponenti bazirana je na „PIONA” analizi. Grupisanje energija aktivacija je uvedeno, kako bi se različite vrednosti energija aktivacije u okviru specifične reakcione klase uzeli u razmatranje. Parametri modela određeni su usaglašavanjem vrednosti dobijenih pomoću uspostavljenog modela sa podacima dobijenim iz industrijskog eksperimenta. Postignuto je veoma dobro slaganje vrednosti parametara procesa dobijenih upotrebom modela i parametara procesa sa postrojenja. Prednost pomenutog modela da veoma dobro predviđa koncentracije vodonika i lakih gasova u odnosu na postojeće modele, predstavlja značajan rezultat. S obzirom na to da je model formulisan na osnovnim principima procesa katalitičkog reforminga benzina, razvijeni kinetički model, uz određene modifikacije, može se primeniti na bilo koji katalitički reformer. U radu je predložen i novi pristup za simulaciju i optimizaciju kontinualnoregenerativnog katalitičkog reformera. Tipični kontinualno-regenerativni proces sastoji se od tri ili četiri reaktora sa reciklom. Reakciona šema i reaktori su matematički opisani preko sistema parcijalnih diferencijalnih jednačina. S obzirom na to da je analiza modela izvedenog za ovaj proces od nekoliko reaktora vremenski veoma zahtevna, razvijena je efikasna simulaciona šema bazirana na kvazi-stacionarnim pretpostavkama. Takođe, u cilju smanjivanja mogućnosti greške uzrokovane kvazi-stacionarnim pretpostavkama, predloženi su novi kriterijumi za fragmentaciju reaktora. Za određivanje parametara procesa uvedena je optimizaciona funkcija, koja je uključila minimizaciju potrošnje energenata. Upotrebljena funkcija cilja predstavlja kombinaciju ekonomskih zahteva i zahteva zaštite životne sredine. Pokazano je da predložena optimizaciona strategija značajnije unapređuje modelovanje procesa. U doktorskoj tezi je razmatrana i mogućnost primene Rankine-ovog ciklusa za poizvodnju električne energije iz izvora niskog toplotnog kvaliteta.Catalytic naphtha reforming is one of the primary processes of naphtha refining. This process is used for the production of the primary component of high-octane motor fuels and also for the production of feedstock for petrochemical industry. This thesis study the technology, process mathematical modeling, strategy for energy optimization, and the direction for future developments of catalytic reformer process. A thermodynamic model has been set up and a semi-empirical pseudo-kinetic model for catalytic reforming has been developed with intention to provide correct process modeling. In order to set up a proper thermodynamic model several models have been tested: Redlich-Kwong, Soave-Redlich-Kwong, Benedict-Webb-Rubin-Starling i Chao-Seader. Based on obtained results, it has been found that the Soave-Redlich-Kwong is the most appropriate model for modeling catalytic naphtha reforming process. In the developed kinetic model, the component “lumping” strategy is based on “PIONA” analysis. “Activation energy lumps” were introduced to take into consideration different values of activation energies within the specific reaction classes. The parameters of the model have been estimated by bench marking with industrial data. Simulation results have been found to be in very good agreement with plant data. Also, one of the significant advantages of the present kinetic model is that it predicts the concentration of hydrogen and light gases very well, comparing to the existing models. Since it was formulated from basic principles, this kinetic model with some modification can be applied to any catalytic reformer. In addition, in the thesis the new approach for simulation and optimization of a continuous catalytic regenerative reformer process was proposed. Typical continuous catalytic regenerative reformer process consists of three to four reactors with recycle. The reaction patterns and reactors are typically modeled using system of partial differential equations. Furthermore, due to the fact that the numerical solution of the entire model developed for this process, consisting of several reactors, is extremely time consuming, the new more efficient method was developed based on quasi-steady state assumptions. Moreover, with the aim of avoiding introduction of large errors in calculations caused by quasi-steady state assumptions the new criteria for reactors fragmentation were proposed. In order to determine optimal values of process parameters new optimization objective function was formulated, minimizing the fuel consumption. The employed objective function constitutes a combined measure for economic and environmental performance. It was shown that proposed method identifies considerable improvements for the process. In the thesis an application of Rankine cycle has been considered for power production using low grade heat

Dynamic Mechanical Behaviour of Polymer Bonded Nd-Fe-B Composite Materials

Magnetic composite materials with varied content of Nd-Fe-B particles in epoxy matrix are examined from a dynamic mechanical perspective. Structural, viscoelastic and magnetic properties of composites have been observed using Scanning Electron Microscope (SEM), Dynamic Mechanical Analysis (DMA) and Super Quantum Interference Device (SQUID) magnetometer, respectively. Experimental results show that magnetic properties and corresponding dynamic mechanical behaviour depend on packing density. Also, results observed by predictive mathematical models suggest that maximal packing factor has a direct impact on elastic behaviour of composites. [doi:10.2320/matertrans.M2011218

Polimerni magnetni kompoziti na bazi Nd-Fe-B

Various types and contents of magnetic powder and polymer matrix induce different mechanical, magnetic, electrical and optical properties of final composite material. The strong influence of relatively small amounts of filler particles on the dynamic mechanical properties of polymers has significantly contributed to increased use of polymer materials in many commercial applications. The higher content of magnetic filler has direct influence on magnetic properties of composites, but also may change the rheology of polymer melt during process and, subsequently, impact the mechanical strength of bonded magnets. For better insight into viscoelastic behaviour of composites, beside experiments, a theory that explicitly takes the shape factor, particle distribution, particle-particle interactions as well as particle-polymer matrix interactions into account is required. The mathematical prediction of storage modulus behaviour is examined. The several proposed analytical models are tested versus experimental results. Some of applied models agree very well with experimental data, whilst others deviate significantly.Različite vrste primenjenih magnetnih prahova i polimerne matrice, kao i njihovi udeli, utiču na mehanička, magnetna, električna i optička svojstva finalnog kompozitnog materijala. Veliki uticaj relativno malih udela čestica punioca na dinamičko mehanička svojstva polimera značajno doprinosi većoj komercijalnoj upotrebi kompozitnih materijala. Veliki udeli magnetnog praha u mnogome utiču na magnetna svojstva kompozita, ali takođe mogu dovesti do reoloških promena u polimeru tokom procesa topljenja, što ima direktan uticaj na mehanička svojstva polimerom vezanih (bonded) magneta. Radi boljeg uvida u visokoelastična svojstva kompozita, osim eksperimenata, neophodno je uzeti u obzir i teorijska razmatranja koja eksplicitno objašnjavaju uticaj faktora oblika, raspodelu čestica, interakcije između čestica, kao i interakcije između čestica i polimera. U tom smislu vršeno je i matematičko predviđanje ponašanja modula uskladištene energije (E') kompozita. Nekoliko predloženih analitičkih modela su testirani i upoređeni sa eksperimentalnim rezultatima. Neki od primenjenih modela se veoma dobro slažu sa dobijenim eksperimentalnim rezultatima, dok neki značajno odstupaju

Hibdridni Nd-Fe-B/barijum-ferit magnetni materijali sa epoksi matricom

Lately, there has been great attention paid to the research of bonded hybrid composites with improved dynamic mechanical capacities capable of replacing bonded Nd-Fe-B magnetic materials, by using cheaper (ferrite) materials instead of the Nd-Fe-B powder while retaining the satisfying values of the maximum magnetic energy. The objective of this study is to assess how different contents of Nd-Fe-B and/or barium ferrite particles can affect morphological, dynamic mechanical and magnetic properties of bonded composite materials. The interactions between employed magnetic powders and the interactions between magnetic powders and polymer binder are considered. For the examination of the magnetic behaviour, a vibrating sample magnetometer (VSM) is used. Different shapes and sizes of the obtained hysteresis loops are used for comparison and prediction of the polymer bonded materials properties. The homogeneous distribution of the magnetic particles in the polymer matrix is validated using scanning electron microscopy (SEM). The elastic and damping behavior examined by dynamic mechanical analysis (DMA) show improved properties for hybrid composite materials.Istraživački trend u oblasti polimerom vezanih (bonded) Nd-Fe-B magnetnih materijala se reflektuje kroz razvoj bonded hibridnih kompozita sa poboljšanim dinamičko-mehaničkim svojstvima i primetno nižoj ceni zbog zamene skupe Nd- Fe-B legure jeftinijim magnetnim materijalima (ferit) uz postizanje zadovoljavajućih vrednosti maksimalne magnetne energije. Cilj ovog rada je da ukaže i predvidi uticaj različitog sadržaja Nd-Fe-B i/ili barijum feritnih čestica na morfološka, dinamičko mehanička i magnetna svojstava bonded magneta. Posmatrane su i analizirane interakcije između magnetnih prahova, kao i interakcije između magnetnih prahova i polimernog veziva i njihov uticaj na finalna svojstva bonded magneta. Za ispitivanje magnetnog ponašanja korišćen je vibraconi magnetometar (VSM). Različite veličine i oblici dobijenih histerezisnih krivih su poređeni i korišćeni za predviđanje svojstava ispitivanih kompozitnih materijala. Homogena raspodela magnetnih čestica u polimernoj matrici je potvrđena korišćenjem skenirajućeg elektronskog mikroskopa (SEM). Elastična svojstva i svojstvo prigušenja oscilacija ispitivano je korišćenjem dinamičko mehaničke analize (DMA) koja ukazuje na poboljšana svojstva kod hibridnih kompozita

Modelovanje i energetska optimizacija progresa katalitičkog reforminga benzina

Catalytic naphtha reforming is one of the primary processes of naphtha refining. This process is used for the production of the primary component of high-octane motor fuels and also for the production of feedstock for petrochemical industry. This thesis study the technology, process mathematical modeling, strategy for energy optimization, and the direction for future developments of catalytic reformer process. A thermodynamic model has been set up and a semi-empirical pseudo-kinetic model for catalytic reforming has been developed with intention to provide correct process modeling. In order to set up a proper thermodynamic model several models have been tested: Redlich-Kwong, Soave-Redlich-Kwong, Benedict-Webb-Rubin-Starling i Chao-Seader. Based on obtained results, it has been found that the Soave-Redlich-Kwong is the most appropriate model for modeling catalytic naphtha reforming process. In the developed kinetic model, the component “lumping” strategy is based on “PIONA” analysis. “Activation energy lumps” were introduced to take into consideration different values of activation energies within the specific reaction classes. The parameters of the model have been estimated by bench marking with industrial data. Simulation results have been found to be in very good agreement with plant data. Also, one of the significant advantages of the present kinetic model is that it predicts the concentration of hydrogen and light gases very well, comparing to the existing models. Since it was formulated from basic principles, this kinetic model with some modification can be applied to any catalytic reformer. In addition, in the thesis the new approach for simulation and optimization of a continuous catalytic regenerative reformer process was proposed. Typical continuous catalytic regenerative reformer process consists of three to four reactors with recycle. The reaction patterns and reactors are typically modeled using system of partial differential equations. Furthermore, due to the fact that the numerical solution of the entire model developed for this process, consisting of several reactors, is extremely time consuming, the new more efficient method was developed based on quasi-steady state assumptions. Moreover, with the aim of avoiding introduction of large errors in calculations caused by quasi-steady state assumptions the new criteria for reactors fragmentation were proposed. In order to determine optimal values of process parameters new optimization objective function was formulated, minimizing the fuel consumption. The employed objective function constitutes a combined measure for economic and environmental performance. It was shown that proposed method identifies considerable improvements for the process. In the thesis an application of Rankine cycle has been considered for power production using low grade heat.Proces katalitičkog reforminga benzina je jedan od glavnih procesa u industrijskoj preradi nafte, koristi se za proizvodnju visoko-oktanskih motornih benzina, kao i za proizvodnju sirovina za procese u petrohemijskoj industriji. U doktorskoj disertaciji razmatrani su tehnologija, matematičko modelovanje procesa, strategija energetske optimizacije i pravci budućeg razvoja procesa katalitičkog reforminga benzina. Za modelovanje procesa katalitičkog reforminga benzina uspostavljen je termodinamički model i razvijen je semi-empirijski pseudo-kinetički model. U cilju primene odgovarajućeg termodinamičkog modela ravnoteže para-tečnost testirano je nekoliko modela: Redlich-Kwong, Soave-Redlich-Kwong, Benedict-Webb-Rubin-Starling i Chao-Seader. Na bazi dobijenih rezultata utvrđeno je da je Soave-Redlich-Kwong-ov model najadekvatniji za modelovanje procesa katalitičkog reforminga benzina. U razvijenom kinetičkom modelu strategija grupisanja komponenti bazirana je na „PIONA” analizi. Grupisanje energija aktivacija je uvedeno, kako bi se različite vrednosti energija aktivacije u okviru specifične reakcione klase uzeli u razmatranje. Parametri modela određeni su usaglašavanjem vrednosti dobijenih pomoću uspostavljenog modela sa podacima dobijenim iz industrijskog eksperimenta. Postignuto je veoma dobro slaganje vrednosti parametara procesa dobijenih upotrebom modela i parametara procesa sa postrojenja. Prednost pomenutog modela da veoma dobro predviđa koncentracije vodonika i lakih gasova u odnosu na postojeće modele, predstavlja značajan rezultat. S obzirom na to da je model formulisan na osnovnim principima procesa katalitičkog reforminga benzina, razvijeni kinetički model, uz određene modifikacije, može se primeniti na bilo koji katalitički reformer. U radu je predložen i novi pristup za simulaciju i optimizaciju kontinualnoregenerativnog katalitičkog reformera. Tipični kontinualno-regenerativni proces sastoji se od tri ili četiri reaktora sa reciklom. Reakciona šema i reaktori su matematički opisani preko sistema parcijalnih diferencijalnih jednačina. S obzirom na to da je analiza modela izvedenog za ovaj proces od nekoliko reaktora vremenski veoma zahtevna, razvijena je efikasna simulaciona šema bazirana na kvazi-stacionarnim pretpostavkama. Takođe, u cilju smanjivanja mogućnosti greške uzrokovane kvazi-stacionarnim pretpostavkama, predloženi su novi kriterijumi za fragmentaciju reaktora. Za određivanje parametara procesa uvedena je optimizaciona funkcija, koja je uključila minimizaciju potrošnje energenata. Upotrebljena funkcija cilja predstavlja kombinaciju ekonomskih zahteva i zahteva zaštite životne sredine. Pokazano je da predložena optimizaciona strategija značajnije unapređuje modelovanje procesa. U doktorskoj tezi je razmatrana i mogućnost primene Rankine-ovog ciklusa za poizvodnju električne energije iz izvora niskog toplotnog kvaliteta

Optimal waste heat recovery and reuse in industrial zones

Significant energy efficiency gains in zones with concentrated activity from energy intensive industries can often be achieved by recovering and reusing waste heat between processing plants. We present a systematic approach to target waste heat recovery potentials and design optimal reuse options across plants in industrial zones. The approach first establishes available waste heat qualities and reuse feasibilities considering distances between individual plants. A targeting optimization problem is solved to establish the maximum possible waste heat recovery for the industrial zone. Then, a design optimization problem is solved to identify concrete waste heat recovery options considering economic objectives. The paper describes the approach and illustrates its application with a case study

Targeting and design of industrial zone waste heat reuse for combined heat and power generation

The basic materials industry contributes significantly to global energy demand. The efficient utilization of energy in these industries is essential to sustainable development. In numerous emerging countries, such industrial activity is concentrated in industrial zones. Typically, significant energy savings can be achieved through the exploitation of symbiotic relationships between companies within such zones. Building upon previous work in waste heat recovery and reuse without consideration of cogeneration, this work establishes a systematic approach to target heat and power cogeneration potentials within industrial zones and to design the corresponding optimal waste heat recovery and reuse networks. The initial focus of the approach is on retrofit solutions that reuse heat and extract power through existing utility systems. The application of the approach is illustrated with a case study

Optimization Approach for Continuous Catalytic Regenerative Reformer Processes

The new approach for simulation and optimization of a continuous catalytic regenerative (CCR) reformer process is proposed. Typical CCR reforming processes consist of three to four reactors with recycle. The reaction patterns and reactors are typically modeled using a system of partial differential equations (PDEs). The numerical simulation solution of the entire model for a process system consisting of multiple reaction zones with recycle is extremely time-consuming and, thus, impractical in optimization studies. That is why we proposed a more efficient simulation and optimization scheme based on quasi-steady-state assumptions. We define criteria for reactor fragmentation to avoid the introduction of large errors in the quasi-steady-state calculations. The optimization problem is formulated with the objective of minimizing fuel consumption. The employed objective function constitutes a combined measure for economic and environmental performance. It is shown that the proposed approach identifies considerable improvements for the process

Development of a Kinetic Model for Catalytic Reforming of Naphtha and Parameter Estimation Using Industrial Plant Data

In the present paper, a semi-empirical kinetic model for catalytic reforming has been developed. In the developed model, the component "lumping" strategy is based on a paraffins, olefins, naphthalenes, and aromatics (PONA) analysis. "Activation energy lumps" are introduced to take into account different values of activation energies within specific reaction classes. The parameters of the model have been estimated by bench marking with industrial data. Simulation results have been found to be in very close agreement with plant data. One of the advantages of the present kinetic model is that it predicts the concentration of hydrogen and light gases very well. Because it is formulated from basic principles, this kinetic model with some modification can be applied to any catalytic reformer