Title Utjecaj pozicije aksijalnog miješala na suspendiranje zeolita i snagu miješanja : završni rad
Title (english) Influence of the position of axial impeller on suspension of zeolite and power consumption : bachelor thesis
Author Robert Kevo
Mentor Marija Ćosić (mentor)
Committee member Nenad Kuzmanić (predsjednik povjerenstva)
Committee member Ivana Smoljko (član povjerenstva)
Committee member Marija Ćosić (član povjerenstva)
Granter University of Split Faculty of Chemistry and Technology (Division of Engineering and Chemistry) Split
Defense date and country 2017-09-27, Croatia
Scientific / art field, discipline and subdiscipline TECHNICAL SCIENCES Chemical Engineering
Abstract Sama uĉinkovitost i ekonomiĉnost miješanja pomoću mehaniĉkog miješala ovisi o možda naizgled ne pretjerano bitnim faktorima kao geometrija posude u kojoj se izvodi miješanje, dimenziji i obliku miješala te njegova poziciji u miješalici. Upravo u ovom radu ispitan je konkretno utjecaj pozicije aksijalnog miješala s lopaticama pod kutomod 45° na suspendiranje ĉestica zeolitaNaX i utrošak snage miješanjapri postizanju stanja potpune suspenzije.Eksperimenti su provedeni u reaktoru u kojem su bila postavljena ĉetiri razbijala virova, a volumen suspenzije iznosio je 2,14 dm 3 . Visina stupca kapljevine bila je jednaka promjeru reaktora (H=d t ), omjer promjera miješala i reaktora (D a /d t ) iznosio je 0,46, a omjeri udaljenosti miješala od dna posude i visine stupca kapljevine (c/H) prilikom ispitivanja su bili od 0,1 do 0,5. Osim udaljenosti miješala od dna posude, sagledavan je i utjecaj masene koncentracije zeolita na stanje potpune suspenzije. Ispitivane veliĉinebile suminimalna brzina vrtnje miješala pri stanju potpune suspenzije, N JS , te zakretni moment, ,pri razliĉitim pozicijama miješala u suspenzijama razliĉitih masenih koncentracija.Iz navedenih veliĉina potom je odreĊen utrošak snage pri miješanju, sve u cilju pronalaženja optimalne konfiguracije miješalice za suspendiranje zeolita. U radu je takoĊer izvršena simulacija toka kapljevine primjenom primjenom programa VisiMix 2000 Turbulent za sve isptivane udaljenosti PBT miješala od dna posude. Na temelju eksperimentalnih ispitivanja utvrĊeno je povećanje kritiĉne brzine vrtnje i zakretnog momenta s povećanjem udaljenosti miješala od dna posude. Navedeno povećanje prisutno je takoĊer i pri porastu masene koncentracije suspenzije, ali utjecaj ove veliĉine nije toliko izražen kao utjecaj pozicije miješala.Utrošak snage miješanja povećava se s povećanjem udaljenosti miješala od dna posude. Njezina najveća vrijednost je bila izmjerena kada je miješalo bilo na polovini visine stupca kapljevine pri masenoj koncentraciji suspenzije 4,91 g/dm 3 . Ipak, osim stanja potpune suspenzije, još je potrebno i odreĊivanje koncentracije izmijenjenih Na + iona na primijenjenom zeolitu da bi mogli predložiti optimalnu konfiguraciju miješalice.
Abstract (english) Sheer efficiency of agitation induced by a mechanical impeller depends on factors that may not seem important at first glance, those being form of the mixing tank in which liquids are agitated, impeller geometry and its position in agitated vessel. In this work, the effect of 45° pitched-blade impeller off- bottom clearance on the state of suspension of NaX zeolite and power consumption is being investigated. All experiments were carried out in a 2.14 dm 3 glass reactor equiped with four baffles. The liquid height was equal to the tank diameter (H = d t ), impeller to tank diameter ratio (D a /d t ) was 0.46 and impeller off- bottom clearances given by ratios (c/H) were in the range from 0.1 to 0.5. Besides impeller position, influence of zeolite mass concentration on the state of complete suspension was analysed as well. Variables examined in this research were minimum impeller speed required to achieve the state of complete suspension, N JS, and torque, , at different impeller position and zeolite mass concentration. Furthermore, from determined values of N JS and τ, power consumptions for applied conditions were calculated. The reason for all these conditions being defined is to assemble an optimal configuration of an agitation process vessel for zeolite suspension. In this work, simulation of fluid flow pattern at different impeller off-bottom clearences by program VisiMix 2000 Turbulent were made as well. According to experimental results, it was confirmed that minimum agitation speed and torque required for achieving the state of complete suspension increases with an increment of impeller distance from the bottom of the tank, as it is the case with the bigger mass concentration, although this effect is not as pronounced as the impeller off-bottom clearance is. Power consumption increased with impeller off-bottom clearance. The highest amount of power is measured when the stirrer was positioned at the half of the liquid height, mass concentration of suspension then being 4.91 g/dm 3 . However, apart from complete suspension, one more thing to consider when making optimal configuration of agitation vessel is concentration of exchanged Na + ions on used zeolite, which was not examined in this thesis.
Keywords
sintetični zeoliti - NaX
PBT miješalo
udaljenost miješala od dna posude
suspendiranje
snaga miješanja
ionska izmjena
zeolit.
Keywords (english)
synthetic zeolites - NaX
PBT impeller
impeller off-bottom clearence
suspension
power consumption
ion exchange
zeolite
Language croatian
URN:NBN urn:nbn:hr:167:108851
Study programme Title: Chemical Technology; specializations in: Chemical Engineering, Environmental Protection Course: Chemical Engineering Study programme type: university Study level: undergraduate Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka kemijskog inženjerstva)
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 2018-04-05 10:53:24