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AbstractAlthough the road-map of the oxy-fuel process seems to be very advanced, there are still plenty of open questions. One of the significant ones is the corrosive behaviour of the heat exchanger surfaces. The Institute of Combustion and Power Plant Technology, University of Stuttgart, performs research on the fireside corrosion under oxy-fuel and conventional combustion conditions for the current and supercritical power plants considering the influence of combustion modus, gas atmosphere and fly ash deposits on the waterwall and superheater surfaces. Since the oxy-fuel-combustion atmosphere is composed of recirculated flue gases and pure oxygen, significantly higher concentrations of CO2, SO2 and H2O are present compared to the conventional combustion of coal with air as an oxidizer. In the here presented study the influence of an oxy-fuel combustion of a hard-coal on the surface of selected superheater materials is discussed and compared to the results obtained for lignite. Especially the interactions between the flue gas atmosphere, ash deposits and heat exchanger materials are studied in detail. The investigation encompassed in this paper has been focused on impacts of oxide-scale growth, carbon enrichment of the materials and sulphur-induced corrosion.Increased sulphur-induced corrosion has been observed in samples exposed to the oxy-combustion atmosphere. The noticed higher depth of corrosive attack of the oxy-fuel samples might be explained by a higher partial pressure of SO2 which is characteristic for oxy-fuel process. Moreover in certain cases the sulphur might be released by the deposits. Beside that, the oxy-fuel samples were exposed to much higher partial pressures of carbon dioxide comparing to the air-case leading apparently to rapid and massive internal carbon enrichment in the oxide scale. Moreover dependence between the chromium content and oxidation ability of the austenitic materials surfaces was noticed under oxy-fuel conditions.

AbstractThe future European energy supply system will have a high share of renewable energy sources (RES) to meet the greenhouse gas emission policy of the European Commission. Such a system is characterized by the need for a strongly interconnected energy transport grid as well as a high demand of energy storage capacities to compensate the time fluctuating characteristic of most RE generation technologies. With the RE generators at the location of high harvest potential, the appropriate dimension of storage and transmission system between different regions, a cost efficient system can be achieved. To find the preferred target system, the optimization tool GENESYS (Genetic Optimization of a European Energy System) was developed. The example calculations under the assumption of 100% self-supply, show a need of about 2,500 GW RES in total, a storage capacity of about 240,000 GWh, corresponding to 6% of the annual energy demand, and a HVDC transmission grid of 375,000 GWkm. The combined cost for generation, storage and transmission excluding distribution, was estimated to be 6.87 ct/kWh.

The European Geosciences Union (EGU) brings together geoscientists from all over the world covering all disciplines of the Earth, planetary and space sciences. This geoscientific interdisciplinarity is needed to tackle the challenges of the future. One major challenge for humankind is to provide adequate and reliable supplies of affordable energy and other resources in efficient and environmentally sustainable ways. This Energy Procedia issue provides an overview of the contributions of the Division on Energy, Resources & the Environment (ERE) at the EGU General Assembly 2017.

Abstract Global primary energy consumption will continue to increase with a high rate to 2050, which will be a big challenge for countries to meet both global and regional energy demand. Pumped storage stations (PSS) integrated to a hybrid power system (HPS) with solar and wind power for China are under construction to tussle with this challenge. Historically, modeling of a PSS integrated HPS has been ignored the interaction effect between the shaft vibration and the governing strategies, which will increase the dynamic risk of PSS disconnected immediately to HPS. Here we unify the models of the hydro-turbine governing system and hydro-turbine generator units with a novel expression of hydraulic forces. We quantize all the parameter’s interaction contributions of PSS integration to HPS and validate this model with the existing models. Finally, we show the feasibility of PSS’s model in integrating of a HPS under steady and fault scenarios.

Abstract The main objective of this study was to develop a thermodynamic model to analyse engine performance and combustion behavior of a single cylinder, four-stroke, naturally aspirated, direct injection (DI) diesel engine. The model was developed with a commercial GT-Power software. Various sub-models for different systems including intake, exhaust, fuel injection, combustion, and heat transfer rate were combined for thermodynamic analysis of engine performance and combustion behaviour. The engine rotational speed, start of injection timing and compression ratio were considered as variables. The engine rotational speeds were varied from 800 rpm to 2500 rpm, the start of injection timings was ranged from 15o crank angle (CA) before top dead centre (bTDC) to 15o CA after top dead centre (aTDC), and the compression ratios were changed from 13 to 25. Performance parameters such as indicated and brake power, brake thermal efficiency, friction, etc. and combustion parameters such as heat transfer rate and in-cylinder pressure are analysed at different engine rotational speed, injection timing, and compression ratio, and discussed accordingly. The optimum performance such as BTE, BT and BMEP were found at the engine speed of 1700 rpm, a start of injection timing of 10o bTDC, and a compression ratio of 20

Abstract Renewable energies are getting progressively widespread due to the growing worry of carbon discharges. There has been a substantial volume of advancement being made in renewable energy sources. One of the remarkable ones is wind power. The common myths of building a wind turbine in highways suburban, and coastal areas are the extent of the machine, and the turbulence may affect the performance of the turbine that ultimately may uncover a poor return on investment. In this paper, some laboratory testing was performed on a conventional turbine and a wind lens turbine to determine if there are any potential applications for the Wind lens turbines in a turbulent environment. Highways, coastal and suburban areas may prove appropriate for this kind of turbine. However, there is still additional analysis required on the effects that these turbines may have on local fauna migration patterns. It is also important to check if the noise pollution generated by the wind lens turbines are enough to cause disruption. Two different types of edges were also embraced to see whether performance in such a location relies more on blade type than the design of the turbine. From the testing in a lab-scale wind tunnel, it was found that on average the wind lens design provided a 40% increase in efficiency both in the Betz coefficient and tip speed ratio of the turbine. However, the wind lens turbine requires further assessment to determine its suitability in environments not exposed to constant wind currents such as highways. There is a possibility that the wind lens turbine can be applied in a turbulent setting with further assessment and enhancements to the manufacturing process of the turbine models.

AbstractAmine based solvent used for CO2 capture can be lost during the process due to: degradation, vaporization, mechanical losses and aerosol (mist) formation. Only recently, studies have appeared pointing out that aerosols can dominate the total amine emission at pilot plant scale behind coal fired power plants. Future full scale amine scrubber installations will be imposed emission limit values (ELV) for a number of components including NH3 and the amine itself. Most likely these ELV will be expressed as maximum concentrations tolerated in the CO2 poor flue gas leaving the stack so it is important to prevent or cure amine aerosol emission. The study presents a novel combination of two existing measurement techniques, that measure: (i) amine emissions from the top of the absorber using FTIR and (ii) PSD of the incoming flue gas using the ELPI+. The study is the first to show how combining these two measurement techniques allows to predict the presence or absence of mist formation. This hypothesis is based on information obtained during several measurement campaigns on different pilot plants.

AbstractWorld-wide coal reserves can supply the global demand for primary energy for several centuries. However, low thickness and structural complexity may constrain the economic exploitation of many coal deposits. Taking into account these circumstances, underground coal gasification (UCG) can offer an economical and sustainable approach for coal exploitation and subsequent feedstock generation from the syngas. The UCG process produces a high-calorific synthesis gas mainly consisting of methane, hydrogen and carbon dioxide, which can be used for electricity generation or feedstock production at the surface. Considering the latter, the Urea process can be applied to establish the nitrogen based fertilizer carbamide (CH4N2O). The required feedstock for carbamide production in the Urea process can be supplied by UCG syngas. The aim of the present study was the development of an integrated carbon utilisation concept based on the coupled UCG-Urea process. A significant amount of carbon dioxide from the UCG synthesis gas is required for carbamide production in the Urea process, while the excessive carbon dioxide can be re-injected into the cavities resulting in the coal seams and surrounding strata after the gasification process. Thus, a new approach for utilisation of carbon dioxide resulting from coal combustion was developed to provide a coupled technology also comprising geological storage of excessive carbon dioxide. A theoretical feasibility study considering UCG-Urea process economics and potentials of UCG and carbon dioxide storage in the gasified strata was conducted for a selected study area in northern Bangladesh revealing the high competitiveness of the combined technology on the international feedstock markets.

AbstractThe CO2-neutral self-supply of heat and electric energy is an important objective for new and existing buildings in the future [1,2]. Therefor the energy autonomous house (EAH) as a new concept for single-family buildings in central Europe is presented. It represents a further development of the solar and efficiency house concepts based on full self-sufficiency in thermal (partly provided by a fireplace) and electrical energy (100%). Two occupied houses have been built in Germany and they are under an extensive scientific monitoring with real user behavior since 2014. This contribution is focused on thermal energy balances and the differences due to different user behavior and the influence of weather conditions. The evaluated solar fraction was fsol, th ≥ 71.4% and fsol, el ≥ 91.8% for both houses in 2014. So far the 100% autonomy in electricity could not be reached due to the unusual low irradiation in Jan. and Dec. 2014 (-24% / -37% compared to long term values). Nevertheless the planned low electricity consumption of ∼ 2000 kWh/year could nearly be achieved, whereby a self-consumption rate of electric energy gains of ≥ 31.8% were assumed. Further findings of 1 ½ years of monitoring of the two EAH are presented within the paper.

AbstractWe measured dissolved inorganic carbon (DIC) stable isotopes (813CDIC in ‰) of brine from an observation well within the first aquifer above the CO2 reservoir at the Ketzin pilot site, to test weather these can detect potential CO2 leakage. The monitoring revealed that DIC concentrations and 813CDIC values were masked by the used high alkaline drilling mud, even eight months after well development. However, subsequent changes in 813CDIC and DIC from of -27 ‰ and 165mg L−1 to -23.5 ‰ and 116mg L−1 reflect most likely a shift towards pristine values of the aquifer.