magistrsko delo
Nejc Vovk (Author), Jure Ravnik (Mentor), Martin Bricl (Co-mentor)

Abstract

Za termoenergetske postroje so države postavile pravila, ki narekujejo omejitve emisij zdravju škodljivih plinov. Ta pravila so povzročila razvoj tehnologij čiščenja dimnih plinov, emitiranih iz termoenergetskih postrojev. Eden največjih onesnaževalcev je žveplov dioksid (SO2), ki nastaja pri zgorevanju premoga, onesnaženega z žveplom. V magistrskem delu obravnavamo mokri kalcitni postopek, ki zahteva izgradnjo pralnika dimnih plinov. V pralniku se žveplov dioksid absorbira v kapljice vode, v katerih je raztopljen apnenec. V reakciji ki poteče, nastane kalcijev sulfid (CaSO3), ki ob prenasičenju v vodi tvori kristale. Nastala suspenzija se zbira v spodnjem delu pralnika – rezervoarju, ki skrbi za tvorbo stabilnega produkta, kalcijevega sulfata (CaSO4). Slednje je izvedeno s prisilno oksidacijo, z uporabo kombinacije razpršilnih šob in mešal (agitatorjev), ki poskrbijo za čim daljši zadrževalni čas disperzne faze. Predstavljen je numerični model rezervoarja pralnika dimnih plinov, s katerim simuliramo večfazni tok v rezervoarju. V tem modelu obravnavamo tok zvezne faze (vode) in disperzne faze (mehurčkov zraka). Modelirano je vpihovanje zraka v področje pred agitatorji, vpliv tokovnega polja agitatorjev na distribucijo disperzne faze in obtočne črpalke, kot iztok tekočine iz rezervoarja. Razvoj Sauterjevega premera mehurčkov je modeliran po populacijskem modelu. Namen izdelave modela je bil analizirati vpliv obtočnih črpalk, ki domnevno motijo učinkovito disperzijo zraka. Rezultati kažejo, da izteka največ zraka skozi obtočno črpalko v skrajni legi, skupno pa skozi obtočne črpalke uhaja 1.2 % vpihanega zraka oz. 0.03 m3/s. Preračun je izveden v odprtokodnem programskem paketu OpenFoam v10, z uporabo superračunalniške infrastrukture v okviru projekta HPC RIVR.

Keywords

pranje dimnih plinov;disperzija zraka;numerični model;OpenFoam;superračunalnik;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FS - Faculty of Mechanical Engineering
Publisher: [N. Vovk
UDC: 004.414.23:662.963(043.2)
COBISS: 168606723 Link will open in a new window
Views: 89
Downloads: 33
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Other data

Secondary language: English
Secondary title: Numerical modelling of two-phase flow inside wet flue gas scrubber sump
Secondary abstract: Countries have set rules for thermal power plants that dictate limits on emissions of harmful gases. These rules caused the development of technologies to clean the flue gases emitted from thermal power plants. One of the biggest pollutants is sulfur dioxide (SO2), which is produced by burning sulfur-contaminated coal. In the masters thesis we examine a wet calcite process, that requires the construction of a flue gas scrubber. Inside the scrubber, sulfur dioxide is absorbed into water droplets that contain dissolved limestone. The reaction that takes place produces calcium sulfide (CaSO3) which forms crystals when supersaturated in water. The resulting suspension is collected in the lower part of the scrubber, called the sump, which ensures the formation of a stable product, calcium sulfate (CaSO4). The latter is achieved by forced oxidation, using a combination of spargers and agitators to ensure that the dispersed phase is retained for as long as possible. A numerical model of the flue gas scrubber sump is presented, to simulate the multiphase flow inside the sump. In this model, the flow of continuous phase (water) and dispersed phase (air bubbles) are considered. The air blowing in front of the agitators, the influence of agitator flow field on the distribution of dispersed phase and recirculation pumps as the outlets are modeled. The development of bubble Sauter mean diameter is modeled using the population balance model. The purpose of the model is to analyze the influence of recirculation pumps, which are assumed to interfere with the effective dispersion of air. Results show that most of the air escapes through the pump outlet near the agitator. A total of 1.2 % (0.03 m3/s) of the entrained air escapes through the pump outlets. The calculation is performed in the open source software package OpenFoam v10, using the supercomputer infrastructure of the HPC RIVR project.
Secondary keywords: flue gas scrubbing;air dispersion;numerical model;supercomputer;
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za strojništvo, Energetsko, procesno on okoljsko strojništvo
Pages: 1 spletni vir (1 datoteka PDF (XII, 75 f.))
ID: 19751374