Title Utjecaj tipa miješala na ionsku izmjenu u šaržnom reaktoru sa i bez razbijala virova : diplomski rad Title (english) Effect of impeller type on ion exchange in baffled and unbaffled batch reactor : diploma thesis Author Zrinka Miljak Mentor Sandra Svilović (mentor)Committee member Ladislav Vrsalović (predsjednik povjerenstva)Committee member Ivana Generalić Mekinić (član povjerenstva)Committee member Sandra Svilović (član povjerenstva)Granter University of Split Defense date and country 2018-10-26, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Mehanička operacija miješanja djeluje vrlo jednostavno, ali utjecaj mnogobrojnih hidrodinamičkih uvjeta na procese koji se odvijaju unutar reaktorskog prostora potrebno je detaljno istražiti. U ovom diplomskom radu ispitan je utjecaj tipa miješala na ionsku izmjenu bakra na zeolitu NaX. Ispitivanja su provedena u reaktoru s razbijalima virova kao i u reaktoru bez razbijala virova kako bi se dobio uvid na sveukupni utjecaj stvorenih hidrodinamičkih uvjeta na već spomenuti proces ionske izmjene. Eksperimenti su izvedeni pojedinačnom primjenom triju miješala: turbinskog miješala s ravnim lopaticama (SBT), turbinskog miješala s lopaticama nagnutim pod kutom od 45° (PBT) i turbinskog miješala s diskom i ravnim lopaticama (Rushtonova turbina, RT). Ispitivanja su provedena sa česticama zeolita promjera d p <0,050mm, a početna koncentracija otopine bakrova(II) nitrata bila je 7,04 mmol L -1 . U cilju dobivanja boljeg uvida u utjecaj ispitivanih parametara određena je minimalna brzina vrtnje miješala potrebna za postizanje stanja potpune suspenzije (N JS ) primjenom Zwieteringovog vizualnog kriterija „1s“, kao i utrošak snage miješala (P JS ). Dobiveni rezultati pokazali su da se prilikom rada u reaktoru s pregradama troši više energije na cjelokupan proces. Iz rezultata ispitivanja utjecaja hidrodinamičkih uvjeta stvorenih SBT, PBT i RT miješalom u reaktoru sa ili bez razbijala virova, može se zaključiti da je proces ionske izmjene općenito brži u reaktoru s razbijalima virova. U isto vrijeme vrijednosti N JS i utroška snage miješala (P JS ) također su veće u reaktoru s razbijalima virova. Provedena je i kinetička analiza procesa kojom se pokazalo da količina izmijenjenog bakra u početnoj fazi eksperimenta naglo raste nakon čega dolazi do uspostave ravnoteže. Dobiveni rezultati obrađeni su metodom nelinearne i linearne regresije korištenjem Ritchievog i Weber-Morrisovog modela i statističkim pokazateljem ocjenjeno je njihovo slaganje s eksperimentalnim podacima. Pokazalo se da brzina kemijske reakcije ovisi o tipu miješala i da je općenito veća u reaktoru s razbijalima virova u odnosu na reaktor bez razbijala virova. Brzina reakcije je najveća kada se koristi RT miješalo u reaktoru s pregradama, a najsporija kod RT miješala u reaktoru bez pregrada.
Abstract (english) Mixing, as mechanical operation, appears like very simple unit operation, but effects of many hydrodynamic conditions on processes inside of reactor need to be examined in detail. In this work the influence of impeller type on ion exchange of copper on zeolite NaX has been investigated. In order to get a better insight into the effect of hydrodynamic conditions on ion exchange, experiments were conducted in the baffled and unbaffled batch reactor at standard impeller off-bottom clearance (C/H=0,33). Three impeller types were used- straight blade turbine (SBT) which produced radial flow, pitch blade turbine (PBT) that produced dominantly axial flow and Rushton turbine (RT) which also produced radial flow. To avoid the effect of intraparticle diffusion, in all experiments the same zeolite particle size (d p <0,050mm) was used, as well as the same initial concentration of copper solution (c 0 =7,04 mmol/L). In order to get a better insight into the effects of the investigated parameters the minimum impeller speed for complete suspension (N JS ), using visual Zwietering criterion “1s”, and power consumption (P JS ) were found. Results have shown that power consumption (P JS ) is generally higher in baffled batch reactor. From the results of the study of influence of the hydrodynamic conditions generated by SBT, PBT and RT impeller in the reactor with or without baffles, it can be concluded that the difference in maximum amount of exchange is not significant and that the reaction, in generally, is faster in the baffled reactor. But, at the same time, N JS and P JS in a baffled reactor were higher as well. Also, kinetic analysis of the process was conducted, and results have shown that the amount of copper exchanged, at examined conditions, in the initial phase of the experiment was increasing rapidly until equilibrium has been established. The obtained results were processed by the nonlinear and linear analysis using Ritchie and Weber-Morris model. Results have shown that chemical reaction rate depends on the impeller type and that generally is higher in baffled reactor. The reaction rate was the highest using RT impeller in baffled batch reactor, and the lowest using RT impeller in unbaffled batch reactor.
Keywords
sintetični zeoliti-NaX
miješalo SBT
miješalo PBT
miješalo RT
razbijala virova
kinetika
ionska izmjena bakra
Ritchiev model
Weber-Morrisov model
Keywords (english)
synthetic zeolites-NaX
impeller SBT
impeller PBT
impeller RT
baffles
kinetics
ion exchange of copper
Ritchie model
Weber-Morris model
Language croatian URN:NBN urn:nbn:hr:167:101811 Project Number: 8959 Study programme Title: Chemical Technology; specializations in: Materials, Environmental Protection, Mediteranean Cultures Type of resource Text File origin Born digital Access conditions Open access Terms of use Public note Ključne riječi doradio knjižničar/ Key words are revised by the librarian. Created on 2018-11-26 12:44:32
