Little is known, understood, or published outside the nuclear sector about chemotoxic safety within the industry. Chemotoxic safety in the nuclear industry is a broad topic area which primarily examines the risks posed to human health by substances and mixtures from their chemical and physical properties. This includes hazards which can cause harm to health, physical harm, or asphyxiation.
Commanding multiple energy storage systems (ESSs) to provide grid balancing services is a popular approach to manage the finite state-of-charge (SoC) of each asset. The communication between the individual assets can be a challenge due to their distribution throughout the land-based power network. Two battery-based ESS, a 240 kW 180 kWh lithium ion polymer (nickel manganese cobalt oxide (NMC)) based system located behind-the-meter on a 400 V power network, and a 2 MW 1 MWh lithium-titanate system, which is located at an 11 kV residential substation, are located 100 km apart. Their performance when delivering grid support services using simple time or frequency synchronised coordinated dispatch methods is evaluated in this research. Experimental results from the real and reactive power step profiles show both energy storage systems (ESSs) are correctly time dispatched, and operate according to the power profile. In the real power test, the 2 MW ESS had a larger SoC change at the end of the discharge period when compared to the 240 kW system, due to its higher power to energy ratio. The reactive power test demonstrated that both systems were able to influence their local voltage. The dynamic demand response profile shows the successful use of frequency to determine the dispatch, and both ESSs delivered or absorbed the correct real power for the frequency deviation, while achieving a 100% service performance measure.
Heating and cooling account for about half of the EU’s final energy demand, while biomass currently accounts for more than 90 % of all renewable heat. Combined Heat and Power (CHP) plants using biomass represent a promising technology for increasing the share of renewables in the EU. However, the main problems arising from the use of biomass are ash-related problems caused by the ash composition, which limits steam temperatures and consequently the efficiency of the plant. The Biofficiency project aims to enable secure and almost carbon-neutral heat and power generation at the highest possible efficiencies while reducing environmental risks and paving the way for a sustainable development in ash utilisation. This article provides an overview of the project goals, the approach as well as some basics and first results towards a better understanding and more sophisticated handling of ash-related problems for the next generation of highly-efficient and sustainable CHP plants.
Oxygen carrier aided combustion (OCAC) is a novel combustion method and a spin-off from chemical-looping combustion (CLC). The core of the technique lies in the utilization of an oxygen carrier (OC) as bed material, and the purpose to enhance the distribution of oxygen in fluidized bed (FB) boilers. The concept combines the robustness of the well-established technology FB boilers with the novel features of oxygen active properties introduced by the OC. Due to several similarities, the OCAC concept can also contribute with knowledge in a transitional path for the scale-up of other chemical-looping techniques, such as CLC, from lab to industrial scale. In this work, the first experiences are presented where a 75,000 kWth CFB-boiler has been operated with ilmenite (FeTiO3) as bed material during 12,000 hours with municipal solid waste as fuel. The investigation shows that ilmenite can replace the commonly used bed material silica-sand without any retrofitting of boiler equipment, and that ilmenite enhances the mass transfer of oxygen inside the furnace. The results show that ilmenite can drastically reduce the amount of carbon monoxide in the flue gas, even when the furnace is operated with an oxygen concentration that is lower compared to ordinary silica-sand operation. Even though still being in the early stages, this concept can contribute to overcome the threshold of understanding the mass transfer and mixing conditions in industrial conditions to enable scale-up of CLC.
The paper proposes an approximated yet reliable formula to estimate the frequency at the buses of a transmission system. Such a formula is based on the solution of a steady-state boundary value problem where boundary conditions are given by synchronous machine rotor speeds and is intended for applications in transient stability analysis. The hypotheses and assumptions to define bus frequencies are duly discussed. The rationale behind the proposed frequency divider is first illustrated through a simple 3-bus system. Then the general formulation is duly presented and tested on two real-world networks, namely a 1,479-bus model of the all-island Irish system and a 21,177-bus model of the European transmission system.
The successful realization of a wind energy project, i.e. a wind farm, wind plant or, in its simplest form, a single wind turbine generator, WTG, strongly depends on accurate assessment of wind energy resources at the target location. While larger wind energy projects include extensive wind resource measurements, this is typically not feasible for small-scale wind applications. This paper presents a simple linear regression model for evaluating wind energy resources at unmonitored sites, based on the correlational analysis of a limited number of sites where wind energy measurements are available. The methodology is illustrated on two regions in Scotland, where wind speed and wind direction measurements are publicly available from 26 UK Met Office stations. The presented approach requires only the coordinates of the enduser's WTG location to estimate the available wind energy and incorporates a method to identify the best-fit WTGs for the calculated wind energy resource. For the selection of WTG, a database of 200 small-scale wind turbines available to UK endusers was constructed, reflecting the current state of the market.
For the Ringhals-2 nuclear power plant, three installed centrifugal pumps were designated to have a combined High Head Safety Injection function, as well as a Chemical Volume Control System function. The pumps were originally installed with rubber bellow type mechanical seals, which over time had demonstrated an unreliable sealing performance by displaying high leakages. In 2002, the Ringhals Maintenance engineers initiated to identify a more reliable and robust shaft sealing solution. In 2007, the project was launched and the installation of the first, new mechanical sealing solution took place in the autumn of 2011. In October 2014, these mechanical seals were dismantled and inspected. The inspection confirmed the expected reliability of the new solution.
In dieser Arbeit werden die Wirksamkeit der Ammoniumsulfatzugabe auf die Reduktion der Hochtemperatur-Chlorkorrosion und deren Einfluss auf die Partikelbildung und Gaszusammensetzung an einem mit Altholz gefeuerten Kessel untersucht. In einer Kraftwerksmessung wurden die Auswirkungen der Ammoniumsulfat-Eindusung auf die Korrosion, Partikelbildung, -grosenverteilung, -zusammensetzung und die HCl-Konzentration im Rauchgas untersucht. Dazu wurde die eingeduste Menge an Chlor-Out®, die im Normalbetrieb 120 kg/h betragt, auf 75%, 50% und 25% reduziert. Bei allen vier Betriebspunkten wurden folgende Messungen durchgefuhrt: - Die Bestimmung der Massenkonzentration von gasformigen Chloriden, angegeben als HCl, in Anlehnung an die DIN EN 1911. Die Reaktionsgleichungen sagen eine Abnahme der HClKonzentration mit abnehmender Chlor-Out® Eindusung voraus. - Die Bestimmung der Partikelanzahl, deren Grosenverteilung, sowie die chemischen Zusammensetzung der Partikel im Rauchgas. - Eine Rauchgasanalyse zur Bestimmung der Gaszusammensetzung. Die Reduktion der Ammoniumsulfat-Eindusung zeigte deutlichen Einfluss auf Rauchgaszusammensetzung: Der Chlorwasserstoffanteil im Rauchgas sank, ebenso die SO2-Konzentration. Auch die Partikelzusammensetzung und -grosenverteilung wurde durch die Reduktion deutlich in ihren Werten beeinflusst.
Die Deregulierung des Energiemarktes und die zunehmende Integration erneuerbarer Energieerzeugung in das Netz haben zu neuen, hochdynamischen Anforderungen an die Kraftwerke geführt, die mit klassischen Regelungen vom PID-Typ teilweise nicht mehr zu bewältigen sind. In dem vorliegenden Beitrag wird ein moderner, multivariabler Regler zur Regelung des Füllstandes der Niederdrucktrommel im 450-MW-GuD-HKW München Süd der Stadtwerke München beschrieben. Die bisher eingesetzte Struktur aus zwei PI-Regler-Kaskaden setzte dem Betrieb enge Grenzen hinsichtlich der Blockdynamik und der entsprechenden Fähigkeit, Sollwerten aus der Netzregelung zu folgen. Daher wurde ein beobachtergestützter, multivariabler Zustandsregler konzeptioniert.
Long-term simulations of electric power systems are an essential tool for power system planning and operation. As power systems are extraordinarily complex, simplifying assumption have to be made to find computational tractable model formulations. In this paper we define aggregation methods 1) for simulation time, 2) for generation units and 3) for load demand units. The performance of the aggregation models is checked against detailed models including binary effects such as minimum down-time, minimum generation or demand side contracts. The aggregation models show very similar behavior, while a significant speed-up in simulation time is observed.
