Uporaba računalniško podprte procesne tehnike za integracijo industrijskih procesov

doktorska disertacija

Hella Tokos (Author), Zorka Novak-Pintarič (Mentor)

Abstract

Procesna integracija je učinkovito orodje, ki omogoča podjetjem, da obstoječo proizvodnjo prilagodijo načelom trajnostnega razvoja, saj lahko z integracijo znižajo porabo sveže vode, toplote, električne energije in drugih virov ter zmanjšajo okoljske obremenitve. Orodja računalniško podprte procesne tehnike, ki temeljijo na matematičnem programiranju, omogočajo sistematično in simultano obravnavanje procesnih problemov. Uporaba v realnih industrijskih primerih pogosto zahteva različne modifikacije modelov, da bi jih prilagodili dejanskem stanju v proizvodnji in dobili uporabne rezultate za podjetje. V doktorski disertaciji smo se osredotočili na znižanje porabe treh najpomembnejših virov, tj. vode, toplote in električne energije, ter na kvantitativno oceno trajnostnih kazalcev. V primeru integracije vodnega sistema smo izhajali iz mešanega celoštevilskega nelinearnega problema (MINLP), ki sta ga razvila Kim in Smith (2004) za načrtovanje šaržnih vodnih sistemov. Njuno matematično formulacijo smo nadgradili za potrebe študijskega primera z možnostmi za: a) ponovno uporabo vode med kontinuirnimi in šaržnimi pocesi, b) namestitev zbiralnika za neizkoriščen odpadni koninuirni tok, ki selahko ponovno uporabi v časovnih intervalih, ko kontinuirni proces ne obratuje in c) namestitev lokalnih čistilnih naprav na mestu nastajanja odpadne vode. Model omogoča izbiro med šaržnimi in kontinuirnimi čistilnimi napravami ter simultano določi časovni načrt obratovanja šaržnih čistilnih naprav glede na nespremenljiv časovni načrt proizvodnje. Za integracijo vodnihsistemov več obratov smo v doktorski disertaciji predlagali večnivojski pristop, ki temelji na uporabi razvitih modelov. Pristop smo preizkusili pri integraciji vodnih porabnikov proizvodnega in polnilnega sektorja na realnem industrijskem primeru pivovarne. V primeru toplotne integracije šaržnih procesov smo izhajali iz mešanega celoštevilskega linearnega problema (MILP), ki sta ga razvila Lee in Reklaitis (1995) za integracijo cikličnih šaržnih procesov. Privzeti model iz literature smo spremenili v treh korakih z namenom, da ga prilagodimo dejanskem stanju v proizvodnji: a) v časovni načrt smo poleg toplih in hladnih tokov vključili tudi procese brez temperaturnih sprememb, b) omogočili smo cepljenje tokov oz. večkratne stike in c) definirali ekonomsko namensko funkcijo namesto relativnega prihranka kot v osnovni formulaciji. Razširjeni problem MILP smo preizkusili na primeru varilnice v pivovarni. Poligeneracijski sistemi omogočajo hkratno pridobivanje električne in/ali mehanske energije ter toplote in hladu iz istega goriva. Za primer pivovarne smo razvili poenostavljen matematični modelMILP za študijo možnosti različnih poligeneracijskih sistemov in izbor optimalnega. V superstrukturo smo vključili kogeneracijske in trigeneracijske sisteme s protitlačno parno turbino in kogeneracijski sistem s plinsko turbino. Podjetja nadzirajo svoj napredek k trajnostni proizvodnji in celotnemu poslovanju s spremljanjem okoljskih, družbenih in ekonomskih kazalcev ter sestavljenega kazalca trajnostnega razvoja. Zato smo poleg ekonomskih učinkov rezultatov procesne integracije analizirali tudi njihov vpliv na trajnostne indikatorje. V študijskem primeru obrata pivovarne bi s predlaganimi integracijskimi ukrepi znižali specifično porabo vode za 25 % in specifično porabo toplote za 3,2 %. Z namestitivijo kogeneracijskega sistema sprotitlačno parno turbino bi znižali strošek nakupa električne energije za 42% in emisijo CO2 za 45 %. Ekonomska upravičenost vseh projektov je pozitivna. Izboljšal bi se tudi indeks trajnostnega razvoja in sicer za 2 %.

Keywords

integracija vodnih sistemov;toplotna integracija;poligeneracija;šaržni procesi;kontinuirni procesi;retrofit;industrijska aplikacija;

Data

Language:	Slovenian
Year of publishing:	2009
Source:	Maribor
Typology:	2.08 - Doctoral Dissertation
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[H. Tokoš]
UDC:	66.011:519.61/.64(043.3)
COBISS:	13508118
Views:	3647
Downloads:	201
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary title:	Computer aided process engineering for integration of industrial processes
Secondary abstract:	Process integration is an efficient tool which enables the reduction of freshwater as well as heat and electricity consumption in existing plants according to the principles of sustainable development. Computer aided processengineering tools together with mathematical programming enable systematic and simultaneous handling of process integration problems. However,mathematical models often need several modifications in large-scale industrial applications in order to suit the specific needs of industrial environment. Models need to be adjusted for existing processes in order to generate useful results for the company. This thesis is focused on reduction of three most important resources, water, heat and electricity. Besides, the sustainability indices are evaluated. In the case of freshwater reduction, the mixed integer nonlinear programming (MINLP) model developed by Kim and Smith (2004), for design of discontinuous water systems was taken as the origin for mathematical modelling. The original formulation was upgraded within this dissertation in order to be applied to the study problem. The following options were included in the model: a) water re-use between continuous and batch processes, b) installation of storage tanks for unused continuous wastewater streams in order to be re-used in subsequent time intervals when the continuous processes are shut down, and c) installation of local treatment units at the production site. Upgraded model enables selectionbetween batch and continuous local treatment units. It performs scheduling of batch treatment unit by simultaneously adjusting treatment schedule to the fixed schedule of batch production. A sequential multilevel strategy was proposed for integrating several water systems and designing the total water network. This strategy relies on the developed models and was applied to the integration of production and filling sections in the case studied brewery. In the case of heat integration, the mixed integer programming (MILP) model by Lee and Reklaitis, 1995, was applied as the basic mathematical formulation for heat integration and scheduling of cyclic batch processes. This formulation was modified in three segments: a) processes without temperature changes were included in the model besides hot and cold streams, b) streams splitting and multiple matches between streams were allowed, and c) economic objective function was defined instead of relative utility savings as in the basic formulation. The modified mathematical model was tested in the brewhouse of the case studied brewery. Polygeneration is an effective technology for combined production of mechanical or electrical, thermal and cooling energy using the same primary energy source, which enablesremarkable energy savings. MILP mathematical model was developed for the case studied brewery in order to perform feasibility studies of several polygeneration systems and select the optimal one. The superstructure includescogeneration and trigeneration systems with back-pressure steam turbine, and cogeneration system with gas turbine. Companies follow the environmental, social and economic indicators, and the composite index of sustainable development in order to improve their control of sustainable performance. For this reason, the impact of process integration results on selected sustainability indicators and the composite index was evaluated besides the economical effects. By realizing the proposed process integrationsolutions, the brewery could reduce its specific water consumption by 25 %, and specific heat consumption by 3,2 %. Installation of cogeneration system with back-pressure steam turbine would reduce the electricity purchase cost by 42 %, and CO2 emission by 45 %. All projects are economically viable, moreover, the composite index of sustainable development would improve by 2 %.
Secondary keywords:	integration of water network;heat integration;polygeneration;batch processes;continuous processes;retrofit;industrial application;Industrijski procesi;Disertacije;Integracija;
URN:	URN:SI:UM:
Type (COBISS):	Dissertation
Thesis comment:	Univ. Maribor, Fak. za kemijo in kemijsko tehnologijo
Pages:	XXIX, 217 str.
Keywords (UDC):	applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;chemical technology;chemical and related industries;kemijska tehnologija;kemijske in sorodne industrije;fundamentals of chemical engineering;osnove kemijskega inženirstva;mathematics;natural sciences;naravoslovne vede;matematika;mathematics;matematika;computational mathematics;numerical analysis;računska matematika;numerična analiza;
ID:	987897