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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.
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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.
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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.
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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.
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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.
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Vliv aplikace různých hnojiv na vybrané půdní vlastnosti
Navrkal, Stanislav
The diploma thesis is focused on monitoring the influence of the application of different fertilizers depending on the vegetation cover on selected physical, physico-chemical and chemical properties of the soil. The experiment took place on the site of the Forage Research Station in Vatín. The experiment was based on a combination of mineral fertilizer, digestate, manure and vegetation covers, permanent grass cover, sowing procedure, monoculture of corn. From each variant in the years 2018, 2020 and 2022, undisturbed samples were taken from a depth of 15 cm to determine the reduced volumetric weight, porosity, maximum capillary capacity, minimum air capacity and disturbed samples up to 30 cm from which the soil reacts and the content of accessible nutrients for plants were determined soil. On the basis of determined values and their trends were found that the digestate does not have any negative effects on soil properties. Nevertheless, the positive effects are, that it should have as representative organic fertilizers were not confirmed.
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Zaplevelení kukuřice a hnojení organickými hnojivy
Robenek, Jakub
In the spring of 2023, field trials were set up on the school farming enterprise Nový Jičín plot to assess weed infestation the application of slurry, farmyard manure, digestate and separate. Liquid fertilisers (slurry, digestate) were applied at a rate of 50 m3, solid fertilisers (manure, separate) were applied at a rate of 50 t/ha. After the application of the selected fertilisers, they were incorporated, followed by tillage and sowing of maize (Zea mays). During the 6th leaf stage of maize, the current weed infestation was evaluated, followed by the application of herbicide, which successfully suppressed the weeds present. The results of the weed infestation showed differences between the fertilization treatments, with the highest weed infestation determined for the manure-fertilized treatment, followed by the digestate, slurry, and separate treatments. On the basis of statistical processing, the following weeds were identified as the most abundant weeds in the manure: red dead-nettle, common field-speedwell, common orache, common amarant, common fumitory, cockspur grass, curled dock, field pansy. The following weeds were present in the slurry: small-flowered cranesbill, cleavers, petty spurge, coltsfoot. The variant fertilised with digestate contained mainly weed species: wild radish, yellow charlock, shepherd’s-purse, field pennycress, field bindweed, rape, fat-hen, creeping thistle. In the part fertilised with separates, the following were mainly represented: field horsetail, mammoth red clover, common chickweed, dandelion, hoary cress, knotgrass, ribwort plantain. The last experimental variant was left without fertilisation, serving as a control. The identified weed species were also used for pH, N, P and salinity analysis as bioindicators. Weed species were divided according to the methodological guidelines into several groups representing certain criteria. During the comparison of the weed species criteria with the theoretical properties and character of the selected fertilizers, a conclusion was established in which the weed indications for each variant could be considered identical to the properties and character of the fertilizers.
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Nutrients recovery by processing liquid digestate
Štylárková, Petra ; Vondra, Marek (referee) ; Touš, Michal (advisor)
Biogas plants produce a large amount of digestate or liquid digestate annually, which can be further processed to obtain nutrients. This method is not widespread due to high investment costs. In this paper, technologies for nutrient recovery from liquid digestate as well as a techno-economic model are presented. This model was developed using information from literature and calculations in a process simulator. It is able to calculate the overall balance of the system from the input parameters and to tentatively assess the economic evaluation. The use of the model was demonstrated with a case study of a specific biogas plant. The analysis of the effects of the price parameters showed, among other things, that for the biogas plant in question the sensitivity of the return to a lower price of ammonium sulphate (product) is high, while in the case of struvite (product) even at its low price there is no such sensitivity.
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Control methods for wastewater pH
Picka, Marek ; Vondra, Marek (referee) ; Miklas, Václav (advisor)
The bachelor thesis initially deals with the process of wastewater treatment with a focus on measurement, pH control and related issues. The pH value is an important parameter in wastewater treatment, which influences physical, chemical and biological processes as well as digestate treatment processes. This paper focuses on the process of thickening of digestate from a biogas plant by evaporation, which is normally associated with the leakage of volatile ammonia into the distillate. In order to eliminate this phenomenon, four methods of pH reduction were compared, which leads to the conversion of nitrogen from the volatile undesirable form 3 to the desirable form + 4 or 3 , which does not evaporate into the distillate during the evaporation process but remains in the concentrate, thus yielding a high quality fertilizer. Of the 4 methods discussed, the nitrification method appears to be the best in terms of the quality of the fertilizer output, but its disadvantage is the long retention time. From the point of view of flue gas utilization, lowering the pH by bubbling 2 and acidification with acid is a suitable method. For cases where speed and low acquisition costs are important, pH reduction with acid is preferable, unless high operating costs are a problem. In order to assess the correct method of pH reduction for a particular biogas plant, a techno-economic evaluation and consideration of other operational constraints is required and will be the subject of future work.
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