Evaluation of the technical condition of medium-sized boilers

The recent trend in the steam and electricity production has been both to increase the efficiency of the facility and to keep tightening legislation concerning emission limits. The lifetime of energy equipment is greatly influenced by the operating temperature, pressure and operating characteristics. The new conditions lead the operator to more often changes of these parameters, which has negative influence to the facility in terms of service life. Precise knowledge of the facility being operated and the ability to predict the residual life of its key parts in time is therefore necessary. A new methodology for determining the residual life and evaluating problematic situations of medium size boilers was developed at Brno University of Technology. Its approaches and advantages will be presented in this paper. The methodology provides the user with approaches for the lifetime evaluation of an equipment as a whole, based on detailed knowledge of the equipment being investigated and the ongoing damage. Additionally, if the equipment is continuously evaluated, it is possible to extend the inspection interval or to achieve a significantly higher lifetime of the entire equipment, thereby reducing the economic cost. If defined criteria are met, the methodology also allows inclusion of FEM and CFD simulations for achieving higher relevance of the results

Thermal load non-uniformity estimation for superheater tube bundle damage evaluation

Industrial boiler damage is a common phenomenon encountered in boiler operation normally which usually lasts several decades. Since boiler shutdown may be required because of localized failures, it is crucial to predict the most vulnerable parts. If damage occurs, it is necessary to perform root cause analysis and devise corrective measures (repairs, design modification, etc.). Boiler tube bundles, such as those in superheaters, preheaters and reheaters, are the most exposed and often the most damaged boiler parts. Both short-term and long-term overheating are common causes of tube failures. In these cases, the design temperatures are exceeded, which often results in decrease in remaining creep life. Advanced models for damage evaluation require temperature history, which is available only in rare cases when it has been measured for the whole service life. However, in most cases it is necessary to estimate the temperature history from available operation history data (inlet and outlet pressures and temperatures etc.). The task may be very challenging because of the combination of complex flow behavior in the flue gas domain and heat transfer phenomena. This paper focuses on estimating thermal load on superheater tubes via Computational Fluid Dynamics (CFD) simulation of flue gas flow including heat transfer within the domain consisting of a furnace and a part of the first stage of the boiler

THE EFFECT OF PHOSPHORUS APPLICATIONS ON CHANGES IN THE SOIL CONTENT OF P AND YIELDS OF BARLEY BIOMASS

Abstract Balanced nutrition and fertilisation is essential for soil fertility and a prerequisite for achieving adequate yields and quality of production. (65 -90 -116 mg/kg). Dry matter yields of the aboveground biomass were the lowest in the control treatment not fertilised with P (63.3 g per pot) and increased significantly with the P rate applied (66.7 -68.6 -70.7 g per pot)

Transient Thermal Stress Calculation of a Shell and Tube Condenser with Fixed Tubesheet

The present article deals with transient thermal stress calculation on a safety horizontal shell and tube condenser. This condenser is used in a power plant for cooling of hot steam diverted from the turbine in the case of its emergency shutdown. The standard stress calculation was provided according to the EN 13445 standard in steady regime. As consistent with this calculation, an expansion joint must be used on the shell. The main aim of this article is to describe a detailed calculation of the transient temperature field on the shell and tubes, using finite element method analysis, and longitudinal thermal stresses on the shell and tubes during the start-up process. Transient analyses are useable for more accurate EN 13445 calculation and, furthermore, for fatigue calculation

Nitrogen and sulphur fertilisation affecting soybean seed spermidine content

Soybean (Glycine max [L.] Merr.) is the major protein and oilseed crop worldwide. Soybean seeds are a rich source of spermidine and other polyamines, which have various positive health effects such as anti-ageing, antioxidant or anti-inflammatory properties. Beside its macro-nutritional composition, soybean contains various bioactive compounds adding health-protecting functional properties to soy-based foods. The present research is based on the hypothesis that soil application of nitrogen and sulphur might stimulate soybean seed polyamines in addition to agronomic traits. As effects of fertiliser application on spermidine were unknown before, a respective pot experiment was carried out, applying ammonium sulphate or urea at nitrogen levels of 0, 1 or 3 g per 5 kg soil in two soybean cultivars. The results indicated that cultivars differed significantly in seed yield, thousand seed weight (TSW) and oil content. For both tested cultivars, seed yield, TSW and contents of protein and spermidine were lowest in the unfertilised treatment. The spermidine content increased significantly after the application of each dose of ammonium sulphate (280 - 283 mg kg-1 DM) or the lower dose of urea (267 mg kg-1 DM) as compared to the unfertilised control (228 mg kg-1 DM). The contrast in spermidine levels between non-sulphur (256 mg kg-1 DM) and sulphur (282 mg kg-1) treatments was significant as well, whereas no significant effects were found for the spermine content. The results demonstrate that an application of appropriate doses of nitrogen and sulphur can increase the content of spermidine in soybean seeds apart from affecting other traits. © 2018, Polish Society Magnesium Research. All rights reserved.Internal Grant Agency (IGA) of the Faculty of Regional Development and International Studies of Mendel University in Brno [2016/017

Changes in relationships between humic substances and soil structure following different mineral fertilization of Vitis vinif-era L. in Slovakia

The quantity and quality of soil organic matter (SOM) depending on many edaphic and envi-ronmental factors may change in response to agriculture related practices. The SOM humification process can be supported by the application of mineral fertilizers, but in the production vineyards, such information is lacking. NPK fertilizer alters the soil quality, so the aim of this study was to: (1.) assess the extent and dynamics of different NPK (Control—no fertilization; 1st NPK and 3rd NPK levels) rates to the soil with grass sward cover in a productive vineyard on changes in SOM, humic substances (HS) and soil structure, and (2.) identify relationships between SOM, HS and soil structure. Results showed that the share of humic acids in soil organic carbon decreased only in NPK1 compared to Control and NPK3 treatments. The color quotient of humic substances values in NPK1 and NPK3 increased by 4 and 5%, respectively, compared to Control. Over a period of 14 years, the content of soil organic carbon increased by 0.71, 0.69 and 0.53 g kg–1 year–1 in Control, NPK1 and NPK3, respectively. The content of HS increased linearly with slight differences due to NPK application. The vulnerability of the soil structure decreased due to fertilization—more at the higher NPK-level. The rate of formed soil crust was decreasing in the following order: Control > NPK1 > NPK3. In Control treatment, the relations between SOM, HS and soil structure were most abundant and with the greatest significance, while with the increasing level of NPK, these relations lost their significance

Fertilization with Magnesium- and Sulfur-Supplemented Digestate Increases the Yield and Quality of Kohlrabi

The vegetation pot experiment with kohlrabi (Moravia variety) was established in 2014 and 2015. The experiment included four treatments of fertilization: (1) untreated control, (2) digestate, (3) digestate + Mg + S, and (4) digestate + S. Treatments 2–4 were fertilized with the same N dose. Differences between the years were recorded in all parameters. Compared with the variant with digestate (100%), the kohlrabi yield of the unfertilized variant was demonstrably lower in both years (33.1% and 46.9%). Digestate enriched with the fertilizer containing Mg + S (treatment 3) demonstrably increased the yield of kohlrabi by 10.2% and 15.7% compared with pure digestate (treatment 2). Digestate enriched with the fertilizer containing elementary S (treatment 4) demonstrably increased the yield of kohlrabi (by 7.4%) only in 2015 compared with pure digestate (treatment 2). Except for the year 2015, there were no yield differences between variants 3 and 4. In both years, the lowest content of nitrates in kohlrabi was observed in the unfertilized control (135 and 163 mg NO3−/kgFM, respectively). Following the application of digestate (treatment 2), the content of nitrates (mg NO3−/kgFM) increased to 327 in 2014 and to 509 in 2015. The addition of fertilizers with Mg + S as well as fertilizer with elementary S to the digestate (treatment 3 and 4) significantly reduced the content of nitrates to 295–301 mg NO3−/kgFM (2014) and to 449–468 mg NO3−/kgFM (2015). The content of ascorbic acid did not statistically differ among the four treatments in the two years (268–281 and 311–329 mg/kgFM in 2014 and 2015, respectively). Digestate supplemented with Mg + S (magnesium sulfate) or only with elementary S can be recommended for kohlrabi fertilization prior to the planting in order to reduce dangerous accumulations of nitrates in kohlrabi

Operating tests analysis of liquid biologically degradable waste processing by anaerobic fermentation

This study concerns the analysis of operating anaerobic fermentation systems of agricultural biogas station and implementing a suitable system enabling the use of liquid biowaste. Based on the comparison of the technological solutions and operating parameters of specific equipment a system enabling the utilisation of biowaste has been designed. The tests made use of liquid substrates commercially offered to biogas station operators. The study evaluates practical measurements at an agricultural biogas station in order to evaluate the biogas production from these substrates and the efficiency of transforming input material to usable energy. The use of such treated substrates for the anaerobic fermentation technology may have a substantial influence on the volume of dosed energy crops. The mixture of input substrates consisting of liquid cattle excrements, silage corn, liquid food-processing waste, animal waste and glycerine water was experimentally validated. This mixture was compared with the operation using liquid cattle excrements and silage corn. It was concluded that the proposed composition of input raw materials makes it possible to increase the production of biogas and el. power. On the other hand, it was identified that the energy content of the input raw materials is not optimally transformed into usable energy. Therefore, the proposed mixture of input materials with biowaste is not recommended for use