[diplomsko delo]
Polona Perme (Author), Mihael Drofenik (Mentor), Peter Glavič (Co-mentor)

Abstract

Izločanje škodljivih žveplovih oksidov iz dimnih plinov je v svetu poznano že več kot dvajset let. Najbolj uveljavljen in tudi najbolj učinkovit postopek izločanja žveplovih oksidov iz dimnih plinov je mokrokalcitni postopek. Poglavitne prednosti omenjenega postopka sta učinkovitost in uporaba cenenega absorpcijskega sredstva, to je mletega apnenca, ki je v naravi dokaj razširjen. Proces razžveplanja dimnih plinov v splošnem opisujejo štirje procesi: absorpcija žveplovega dioksida, raztapljanje apnenčeve moke, oksidacija sulfita v sulfat in kristalizacija sadre. V času kontakta med plinsko in tekočo fazo v absorberju se žveplov dioksid absorbira, vzporedno pa se absorbira tudi večina drugih primesi, kot so leteči pepel, žveplov trioksid, klorovodikova kislina, fluorovodikova kislina. Absorbirani žveplov dioksid nato v absorpcijski suspenziji reagira s kalcitom ter se med procesom oksidacije (vpihovanje zraka v suspenzijo pralnika) oksidira direktno do sulfata ter nato kristalizira v sadro, ki je končni produkt razžveplanja. Mokrokalcitni postopek za odstranjevanje SO2 iz dimnih plinov uporablja tudi Termoelektrarna Trbovlje (TET). Za ugotavljanje primernosti posameznih reaktantov — apnene moke in učinkovitosti razžvepljevalne naprave smo analizirali vzorce in spremljali obratovalne parametre štirih slovenskih proizvajalcev apnene moke: Apnenec d. o. o. Zidani Most, Industrija apna Kresnice d. o. o. (IAK), Industrija gradbenega materiala Zagorje d. o. o. (IGM) in Calcit d. o. o. Stahovica. Kemijske analize so se izvajale z vzorci absorpcijske suspenzije ter odcejene sadre vakuumskega filtra. Obratovalni parametri, ti so pretok dimnih plinov, masna koncentracija vtoka SO2 neočiščenih plinov, masna koncentracija iztoka SO2 očiščenih plinov, število delujočih obtočnih črpalk ter oksidacijskih puhal, so se beležili avtomatsko ob odvzemu vsakega vzorca. Absorpcijski suspenziji smo določali gostoto, merili pH, masno koncentracijo nezreagiranega CaCO3, masno koncentracijo neoksidiranega SO32—. Sadri smo določili masni delež CaSO3∙½H2O, preostali CaCO3 ter vlago. Izsledki so pokazali, da med reaktanti posameznih dobaviteljev obstajajo razlike, predvsem glede kemizma reakcije. Primerjava na osnovi enotnih obratovalnih parametrov je pokazala, da reaktant Apnenec — Zidani Most, zagotavlja najbolj učinkovito ter optimalno delovanje naprave za razžveplanje dimnih plinov (NRDP) TET. Izmerjene so najmanjše vrednosti masne koncentracije preostalega CaCO3 v absorpcijski suspenziji. S tem je zagotovljen najbolj učinkovit proces raztapljanja apnenčeve moke. Ravno tako je pri omenjenem reaktantu najbolj učinkovit proces oksidacije sulfita med procesom razžveplanja dimnih plinov z najmanjšo vsebnostjo neoksidiranega SO32— v absorpcijski suspenziji. Na odločitev o izbiri vplivajo tudi specifična poraba in cena apnene moke ter zanesljivost oskrbe. Analize sadre so pokazala, da v primeru obratovanja s katerim koli reaktantom nastaja komercialno kvalitetna sadra, ker izmerjene vrednosti ustrezajo danim kriterijem, ki so bili določeni pri projektiranju naprave. Lahko se odlaga na ustrezno urejenem odlagališču, lahko se uporablja v cementni industriji, za polnjenje rudniških rovov, ali z dodajanjem specialnih dodatkov za različne gradbene izdelke. Dodatne raziskave, zlasti granulometrijska in razširjena kemijska analiza apnene moke, bi dodatno pripomogla k ugotovitvi ustreznosti posameznega reaktanta. Žal se te analize ne izvajajo v laboratoriju TET.

Keywords

razžveplanje dimnih plinov;apnena moka;žveplov dioksid;mokrokalcitni postopek;

Data

Language: Slovenian
Year of publishing:
Source: Maribor
Typology: 2.11 - Undergraduate Thesis
Organization: UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher: [P. Perme]
UDC: 542.745.1(043.2)
COBISS: 13325078 Link will open in a new window
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Other data

Secondary language: English
Secondary title: ǂThe ǂimpact of different reactants on the efficacy of desulphurisation facility in powerplant Trbovlje
Secondary abstract: The elimination of harmful sulphuric oxides from gases has been known for more than 20 years. The most known procedure is the wet calcite technology. The main advantages of it are the efficiency and the use of cheap absorption agent, grinded limestone that is abundant in the environment. The process of desulphurisation of gases is generally carried out in four stages: the absorption of sulphuric dioxide, dissolution of limestone flour, oxidation of sulphite into sulphate, and crystallisation of gypsum. During the process of gas and fluid contact the sulphuric dioxide is absorbed by the absorber, and ingredients, such as flying ashes, sulphuric trioxide, chlorine-hydrogen acid and fluorine-hydrogen acid are absorbed simultaneously, too. The absorbed iron dioxide reacts in the absorber suspension with calcite forming sulphite, which during the next process of oxidation becomes sulphate, and at the end it turns into gypsum which is the final product of desulphurisation. The wet calcite technology is used to remove sulphuric dioxide from the gases also by the Power plant Trbovlje. To be able to determine which reactants are the most appropriate, we analysed and examined different parameters of four producers of limestone flour in Slovenia: Apnenec, d. o. o., Zidani Most, Industrija apna Kresnice, d. o. o., (IAK), Industrija gradbenega materiala Zagorje, d. o. o., (IGM), and Calcit, d. o. o., Stahovica. The analyses of samples taken from the absorption suspension and the drained gypsum of vacuum filter were carried out. Operation/working parameters (the flow rate of gases, mass concentration of sulphuric dioxide at the entrance and exit, the number of working pumps and oxidation blowers) were measured automatically with every sample taken. Density of the absorption suspension was determined, levels of acidity/alkalinity and mass concentration of non-reacted sulphuric trioxide were measured, and also the components and properties of gypsum produced were studied. Our research has shown that there are differences between different reactants. The comparison between different producers showed that the reactant of the company Apnenec Zidani Most enables the best and the most efficient work of the Power plant. We measured the lowest mass concentrations of the calcium carbonate remaining in the absorption suspension. This way the best method for dissolving the limestone flour was established. At the same time the best and the most efficient process of sulphite oxidation during the desulphurisation of gases, and the lowest quantity of non-oxidant sulphuric trioxide in the suspension were determined. Specific consumption and price as well as security of supply of limestone influence the decision making, too. The gypsum analysis has shown that by using different reactants quality gypsum was obtained as the measured values were always within the parameters that were set when the reactor was constructed. This gypsum can be disposed of at a suitable dump; it can also be used in the cement production, or for filling up unused mine shafts, or in construction by adding different additives. Additional research, e.g. granulometric and extended chemical analysis of limestone flour would further help to find the most suitable reactor, but such an analysis could, unfortunately, not be carried out in the laboratory of the Power plant Trbovlje.
Secondary keywords: desulphurisation of gases;limestone flour;sulphuric dioxide;wet calcite technology;
URN: URN:SI:UM:
Type (COBISS): Undergraduate thesis
Thesis comment: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages: 75 f.
Keywords (UDC): mathematics;natural sciences;naravoslovne vede;matematika;chemistry;crystallography;mineralogy;kemija;practical laboratory chemistry;preparative and experimental chemistry;praktična laboratorijska kemija;preparativna in eksperimentalna kemija;working with gases;
ID: 987038