|
|
Mass transfer during desorption
Lindovský, Jiří ; Svěrák, Tomáš (referee) ; Kalivoda, Josef (advisor)
This master thesis deals with development and optimalization of apparatus for ammonia desorption from liquid organic wastes, generated by biogas plant. There is a high ammonia concentration in biogas plant waste products. That limits its application as a fertilizer in an agriculture. The main aim of this theses is finding optimal conditions to reach required efficacy of removing ammonia nitrogen from a liquid digestate. For this purpose, two pilot plant devices were used, and optimal conditions for ammonia desorption with its subsequent absorption by acid solution were investigated. One of the tested devices is a membrane contactor with polymeric hollow fibers. The second is a stripping device, which was used for measuring the pilot scale experiments. At the time of writing of this thesis, the device is subjected to a process of optimalization. The transferred ammonia nitrogen absorbed in acid solution was analyzed by UV-VIS spectrometry. The suitability of both devices for the required ammonia desorption efficiency has been demonstrated. Furthermore, the kinetic curve of the experiment was investigated under different conditions. The optimalization of devices will take place according to the results obtained in the experimental part of this thesis. The optimized devices will be placed in biogas plant full operation.
|
|
|
Assessment of evaporator integration into biogas plant
Peťovský, Patrik ; Touš, Michal (referee) ; Máša, Vítězslav (advisor)
The main waste output of the biogas plant is digested which is used as fertilizer. It can be further process. Digestate cannot be discharged freely into surface waters. This problem is associated with high transportation costs and higher costs of storage tanks in the new biogas plant. The aim of this bachelor thesis is to assess a suitable evaporation system for a particular biogas plant. The evaporation system leads to the concentration of digestate by evaporation water. The system uses heat produced by cogeneration unit. The main consequence of the integration is lower cost for the transport of liquid digestate. The output of the bachelor thesis is a technical and economic evaluation that assesses the payback period depending on the flow of concentrated digestate. The specific costs for adjustment of liquid digestate with regard to the payback period are in the range of 5–15 years. The values do not exceed 210 (Kčyear)/t_fug . The values considering selling heat are even negative. The minimum value guaranteed by the manufacturer is around 260 (Kčyear)/t_fug . The integration of the evaporation system into Žamberk's biogas plant is economically disadvantageous. The thesis brings new knowledge about the potential of multi-stage flash evaporation in biogas plants with short transport distances and high utilization of waste heat.
|
|
|
Membrane technologies for agricultural wastewater treatment
Uhlířová, Marcela ; Touš, Michal (referee) ; Vondra, Marek (advisor)
This thesis deals with an agricultural wastewater treatment (liquid digestate) by membrane technology. There is a fundamental description of characteristics of membrane technology with regard to application of agricultural wastewater treatment in this thesis. Experimental device for treatment of liquid digestate is designed and it consists of three steps – microfiltration, ultrafiltration and reverse osmosis. The first step consists of four filters with different pore sizes (80, 25, 10 and 5 µm). The second step is ultrafiltration and the third and key step is reverse osmosis. In the final step monovalent ions such as NH4+ are separated. Reverse osmosis consists of two stage system which results in higher recovery. Three experiments were carried out in order to verify the efficiency of separation dissolved solids.
|
|
|
Phosphorus recovery from liquid digestate
Heger, Jan ; Procházková, Michaela (referee) ; Touš, Michal (advisor)
The focus of this thesis is the posibility of obtaining phosphorus from liquid digestate. The theoretical part of the thesis is focused on summarizing the current situation regarding phosphorus recovery. The research summarizes the essential information about the method of struvite precipitation, by which phoshphorus is obtained in the form of struvite, which can be further used as a fertilizer. Based on the process information, an experimental device was designed to obtain phosphorus in the form of struvite, corresponding to industry standards. It is a cylindrical vessel with a conical bottom, in which the liquid digestate with the chemicals is mixed with a stirrer. The functionality of the device was tested experimentally on the created device. The results of the experiment were analyzed by XPS method, which confirmed the formation of struvite. For future operation, modifications of the device and pre-treatment of the liquid digestate were proposed, which could improve the whole process and its results.
|
|
|
Digestate Grate Boiler
Krejčiřík, Jiří ; Milčák, Pavel (referee) ; Lisý, Martin (advisor)
This master thesis deals with the properties of digestate in combustion, design of construction solution of digestate boiler and experimental verification of boiler parameters. The first chapter deals with the properties of digestate as a fuel. It is followed by a chapter dealing with the existing measured results on a similar boiler. This is followed by a stoichiometric calculation of the digestate boiler. The next chapter is devoted to combustion chamber models. This chapter is followed by a chapter with experimental verification of chamber models and combustion process tuning. The last chapter contains design of construction and operational measures.
|
|
|
Energy use of digestate
Kaška, Zdeněk ; Štelcl, Otakar (referee) ; Baláš, Marek (advisor)
This bachelor thesis deals with the research of biomass in general, its types and processing. Nowadays, biomass appears to be an environmentally and financially acceptable substitute for fossil fuels due to increasingly stringent emissions standards. The second part deals with its particular type, digestate. It is investigated whether the fossil fuel can be replaced or how the energy production process could be changed.
|
|
|
Optimization of Gasification Process of Biodegradable Wastes
Elbl, Patrik ; Milčák, Pavel (referee) ; Lisý, Martin (advisor)
The aim of the diploma thesis is to discuss the gasification of biodegradable waste. The theoretical part deals with gasification with focus on gasification phases, types of gasification reactors and pollutants contained in the generated gas, especially tar. Further, there is listed the characteristic of alternative biomass fuels, namely digestate and sludge waste. The practical part is devoted to gasification on a fluidized bed reactor with the aim to test the possibilities of gasification of these fuels, to determine their specifications and the influence of various gasification media. In the final part there are discussed the results of the collected gases and tar.
|
|
|
Measurement of selected physical properties of the waste water from biogas plant
Ondruška, Vojtěch ; Zejda, Vojtěch (referee) ; Vondra, Marek (advisor)
The aim of this Bachelor’s thesis is the experimental measurement of physical and chemical properties of the wastewater from biogas plants. Thesis concisely describes wastewater and its origin. The main part is dedicated to the design of experiments and to the detailed description of the measurement of selected properties with the available laboratory methods. Measured data are evaluated and compared to literature. The results of this thesis can be employed to further develop the equipment for thickening wastewater from biogas plants or to other scientific activity in the field of waste management in agriculture.
|
|
|
Foaming of fermentation residues during a vacuum evaporation
Knob, Jan ; Brummer, Vladimír (referee) ; Vondra, Marek (advisor)
The diploma thesis deals with the processing of digestate, which is the remaining material after biogas production. It aims to experimentally prove how chosen operational parameters of antifoaming agents influence digestate foaming associated with the vacuum evaporating technology. Based on the research of available antifoamers and the issue of digestate foaming itself, it was observed how three selected antifoamers (i.e. rapeseed oil, silicone antifoamer Erbslöh Schaum-ex and oleic acid), together with the decrease in the pH factor of the evaporating digestate, influence the final foam production. For the purposes of the research, an apparatus simulating the vacuum evaporating process was set up in which the heated sample was brought to boil by gradual pressure decrease. The process of foaming was observed in a transparent cylinder of a testing culumn. The essential part of the experimental activity is represented by a planned experiment which by means of a DoE (Design of experiments) method proved rapeseed oil to be very efficient. In contrast, other antifoamers, as well as the influence of the pH factor decrease, manifested themselves as insignificant factors, while the oleic acid even supported the foaming. The supplementary measurements led to a more detailed research of the effects of rapeseed oil and to the construction of a mathematical model describing how the concentration of rapeseed oil undermines the amount of generated foam. The main contribution of the thesis is firstly the evidence that rapeseed oil plays an important part in the reduction process of digestate foaming and secondly the determination of minimum substance concentration leading to the foaming reduction of a particular sample which is considered efficient enough to enable functioning of a vacuum evaporator. The thesis has also experimentally demonstrated the influence of some polymer organic flocculants which have been proved to support the foaming.
|
|
|
Integration of a technology for digestate thickening in a biogas plant
Miklas, Václav ; Touš, Michal (referee) ; Vondra, Marek (advisor)
This diploma thesis is mainly focused on the digestate thickening in a biogas plant. First, overview of the biogas technology in the Czech Republic is presented. Furthermore, problems with waste heat utilization and processing of fermentation residues (digestate) are described in more detail. Based on the research, multi-stage flash (MSF) evaporation was chosen as the technology for the digestate thickening. The main part deals with the integration of the chosen technology into a biogas plant process. The programming language Python was used to simplify the given task. In the preliminary stage, a complex mathematical model of a biogas plant was created, focusing particularly on the mass and energy balances. Subsequently, a computational model of the MSF evaporator was programmed. A procedure for the integration was suggested using the sensitivity analyses. Additionally, the model of a biogas plant was extended with the MSF evaporator. The key outcome of the thesis is a technical-economic analysis in which the impact of digestate transport price and electricity feed-in tariff on payback period is investigated. The results suggest profitability of MSF evaporator for biogas plants without subsidized feed-in tariff. Contrastingly, installation of MSF evaporator in older biogas plants with subsidized feed-in tariff can be economically viable only in cases of significantly longer transport distances.
|
guest ::
