Primerjalna analiza obratovanja kemijskega in encimskega reaktorja z nasutjem

diplomska naloga

Tadej Lešer (Author), Andreja Goršek (Mentor), Darja Pečar (Co-mentor)

Abstract

Za uspešno načrtovanje reaktorjev je potrebno poznati enačbo proizvodnosti želene reakcije, kot tudi odvisnost različnih spremenljivk na njeno obnašanje. Študije kinetike reakcij izvajamo v laboratororijskem merilu, katerih rezultate kasneje uporabimo pri dimenzioniranju reaktorja, kot tudi povečavo (scale—up) na večje sisteme. Velikokrat obstaja več reaktorskih sistemov za dosego enakega produkta, zato hočemo izmed njih najti tistega, ki nam daje najboljše rezultate oz. največjo proizvodnost. Da pa lahko ugotovimo, kateri izmed njih je najboljši, naredimo med njimi primerjavo t.i. primerjalno analizo. V okviru diplomskega dela smo študirali reakcijo hidrolize saharoze v kemijskem in biokemijskem reaktorju z nasutjem. Pri kemijskem reaktorju smo uporabili dve velikosti delcev katalizatorja, ki sta znašali, d = 860 µm in d = 303 µm. Osrednji cilj je bil določitev primernejšega sistema za omenjeno reakcijo, kot tudi opredelitev ustreznih kinetičnih parametrov, kot so aktivacijska energija, red reakcije, faktor učunkovitosti, itd. ter na koncu zapisati ustrezno enačbo proizvodnosti. To smo dosegli s preučevanjem poteka reakcije pri različnih pogojih obratovanja, tako, da smo spreminjali obratovalno temperaturo ter napajalni volumski pretok skozi reaktor. Ugotovili smo, da je reakcija hidrolize saharoze preko kemijskega katalizatorja, reakcija prvega reda, ki ima dokaj visoko aktivacijsko energijo (Ea = (67—74) kJ/mol). Proizvodnost reakcije je odvisna od velikosti delcev katalizatorja in je pri manjših delcih večja, kar smo dokazali tudi s izračunom faktorja učinkovitosti. Biokemijski katalizator je pokazal dobro ujemanje z Michaelis—Mentenovo kinetiko, medtem ko sta znašali vrednosti aktivacijske energije, Ea = 19,5 kJ/mol in Michaelis—Mentenove konstante KM = 2,1 mmol/L. V primerjavi med kemijskim in biokemijskim reaktorjem smo ugotovili, da ima kemijski katalizator z velikostjo delcev, d = 303 µm najboljše stopnje presnov, medtem ko je presnova encima, pri njegovi optimalni temperaturi ( = 55 °C) in najboljšem uporabljenem pretoku (qv = 6 mL/min), za 25 % manjša. Kemijski katalizator ima tudi stalilnejše obratovanje, nižjo ceno na uporabljeno enoto ter daljšo življensko dobo. Zato smo za dano reakcijo predlagali uporabo kemijskega katalizatorja.

Keywords

reaktor z nasutjem;saharoza;enačba proizvodnosti;katalizator;kinetika reakcije;

Data

Language:	Slovenian
Year of publishing:	2009
Source:	Maribor
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[T. Lešer]
UDC:	66.023.2.012:[66.094.941:547.458](043.2)
COBISS:	13913110
Views:	2698
Downloads:	208
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Comparative analysis of the chemical and enzyme fixed bed reactor operation
Secondary abstract:	For successful design of reactors it is necessary to know the rate of the desired reaction, as well as the dependence of different variables on its behavior. Experimental studies for reaction kinetics are performed in laboratory scale and the results are later used in the design of the reactor, as well as for magnification (scale-up) to larger systems. There are often several reactor systems that achieve the same product, so we want to find out which one of them gives us the best result or maximum rate of reaction. However, if we wan't to conclude which one of them is the best, we need to make a comparison between them known as comparative analysis. In the range of this diploma, we studied a reaction of sucrose hydrolysis in chemical and biochemical fixed bed reactor. In the chemical reactor, we used two sizes of catalyst particles, which amounted, d = 860 µm and d = 303 µm. The central objective of this work was to determine the most appropriate system for our reaction, as well as identification of appropriate kinetic parameters such as activation energy, reaction order, effectiveness factor, etc., and define the appropriate reaction rate. This was achieved by studying the reaction at different operating conditions, done by changeing operating temperature and volume flow through reactor. We found that the reaction of sucrose hydrolysis, via chemical catalyst is a first-order reaction, which has a relatively high activation energy (Ea = (67-74) kJ/mol). The rate of reaction depends on the particle size of the catalyst and it is greater for smaller particles, which we also proven by calculating the effectiveness factor. Biochemical catalyst showed a good agreement with Michaelis-Menten kinetics, while the value for activation energy was, Ea = 19.5 kJ/mol and the Michaelis-Menten constant KM = 2.1 mmol/L. In a comparison between the chemical and biochemical reactor, we found that the chemical catalyst with particle size, d = 303 µm, gave us best rates, while the conversion of enzyme in its optimal temperature ( = 55 ° C) and the best used wolume flow (qv = 6 mL/min) was 25% lower. Chemical catalyst also has a more stabile operation, lower price on the unit used and a longer life span. Therefore, for a given reaction, we proposed the use of chemical catalysts.
Secondary keywords:	fixed bed reactor;sucrose;reaction rate;catalyst;reactor kinetics;
URN:	URN:SI:UM:
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	X, 50 f.
Keywords (UDC):	applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;chemical technology;chemical and related industries;kemijska tehnologija;kemijske in sorodne industrije;chemical processing operations and equipment in general;kemijska procesna tehnika in oprema na splošno;mathematics;natural sciences;naravoslovne vede;matematika;chemistry;crystallography;mineralogy;kemija;organic chemistry;organska kemija;
ID:	987615