Reducing cycling costs in coal fired power plants through power to hydrogen

The increase of renewable share in the energy generation mix makes necessary to increase the flexibility of the electricity market. Thus, fossil fuel thermal power plants have to adapt their electricity production to compensate these fluctuations. Operation at partial load means a significant loss of efficiency and important reduction of incomes from electricity sales in the fossil power plant. Among the energy storage technologies proposed to overcome these problems, Power to Gas (PtG) allows for the massive storage of surplus electricity in form of hydrogen or synthetic natural gas. In this work, the integration of a Power to Gas system (50 MWe) with fossil fuel thermal power plants (500 MWe) is proposed to reduce the minimum complaint load and avoid shutdowns. This concept allows a continuous operation of power plants during periods with low demand, avoiding the penalty cost of shutdown. The operation of the hybrid system has been modelled to calculate efficiencies, hydrogen and electricity production as a function of the load of the fossil fuel power plant. Results show that the utilisation of PtG diminishes the specific cost of producing electricity between a 20% and 50%, depending on the framework considered (hot, warm and cold start-up). The main contribution is the reduction of the shutdown penalties rather than the incomes from the sale of the hydrogen. At the light of the obtained results, the hybrid system may be implemented to increase the cost-effectiveness of existing fossil fuel power plants while adapting the energy mix to high shares of variable renewable electricity sources.     

Design of a Cost‐Reduced Flexible Plant for Supercritical Fluid‐Assisted Applications

A novel batch plant for supercritical CO₂ applications is proposed which is not equipped with expensive components, such as high‐pressure pumps, making it particularly suitable for bench‐scale use. For the first time, the use of a hanging scale is suggested to weigh the amount of CO₂ required for the experiment and the use of the thermodynamics to reach the working conditions. The rig is able to cover different applications, e.g., aerogel drying, impregnation, and extraction, showing high flexibility. An approximate cost analysis has been performed considering as a reference a 150‐mL vessel. It has been calculated that both the setup and running costs are considerably lower than the common batch and semicontinuous rigs.     

Primary energy demand and energy costs of fixed-bed drying using the example of chamomile flowers

Abstract

Energy use efficiency in the drying of medicinal and aromatic plants is largely determined by weather conditions and process parameters. While the former are beyond control, the latter can be optimized. In order to achieve such optimization, different energy supply variants, based on typical operating conditions of batch-type grate drying in Thuringia, Germany, were analyzed. It was found that partial air recirculation and integration of heat pumps allow substantial savings in primary energy. However, under the constraint of German energy prices, significant savings in energy costs can only be achieved if combined heat and power generation systems are applied at the same time.     

Acceptance of biomass plants – Results of a longitudinal study in the bioenergy-region Altmark

The present contribution addresses the results of a longitudinal study in a ‘bioenergy-region’ concerning the public acceptance of biomass plants and the corresponding influencing factors. Using a standardized questionnaire, 423 persons were polled between 2009 and 2011 on three points of measurement in four places in the bioenergy-region Altmark. One main result of the study is that the reported public acceptance remains constantly high over time; nevertheless it became evident that the respective influencing factors differ in their strength, whereas the perceived regional benefit shows a strong connection to the reported public acceptance of biomass plants at each point of measurement. Concluding the research results, the acceptance of biomass plants doesn't seem to be a fixed construct, but has to be seen in context of the respective experiences with plants on a local level over time.In addition to the local population, key actors of the regional biomass sector were also interviewed (N = 26). The analyses show significant differences in the perception and evaluation of the current informational level between the population and the key actors. Furthermore, the key actors estimated the utilisation of biomass even more positively and expected a greater ‘signal function’ of the bioenergy-region-project compared to the population.     

Stability enhancement of induction generator–based series compensated wind power plants by alleviating subsynchronous torsional oscillations using BFOA‐optimal controller tuned STATCOM

In this paper, a STATCOM (static synchronous compensator) is used to encounter the potential SSR (subsynchronous resonance) observed by IG (Induction Generator) based series compensated wind farms. The basic controller used for STATCOM control is identical to that of the literature. An idea of a unique meta‐heuristic swarm‐based optimization technique called BFOA (bacterial foraging optimization algorithm) based optimal‐controller is introduced for optimal parameter selection of the basic controller used in the control scheme of the STATCOM. The investigation is carried out with 500 MW IG‐based wind farm exposed to three‐phase LLL‐G fault close to the PCC (point of common coupling) and implemented with MATLAB in both steady and transient states for the three different cases, namely, without STATCOM, with the basic STATCOM controller, and in the presence of the proposed BFOA‐optimal controller‐based STATCOM. In both the states, the observed eigenvalues of the test system, together with the time domain results of the generator rotor dynamics for three distinct cases, reveals the effectiveness of the suggested BFOA‐optimal controller tuned STATCOM in mitigating the potential SSR.     

Functional organisation of the endomembrane network in the digestive gland of the Venus flytrap: revisiting an old story with a new microscopy toolbox

Up-to-date imaging approaches were used to address the spatiotemporal organisation of the endomembrane system in secretory cells of Dionaea muscipula. Different ‘slice and view’ methodologies were performed on resin-embedded samples to finally achieve a 3D reconstruction of the cell architecture, using ultrastructural tomography, array tomography, serial block face-scanning electron microscopy (SBF-SEM), correlation, and volume rendering at the light microscopy level. Observations of cryo-fixed samples by high-pressure freezing revealed changes of the endomembrane system that occur after trap activation and prey digestion. They provide evidence for an original strategy that adapts the secretory machinery to a specific and unique case of stimulated exocytosis in plant cells. A first secretion peak is part of a rapid response to deliver digestive fluids to the cell surface, which delivers the needed stock of digestive materials ‘on site’. The second peak of activity could then be associated with the reconstruction of the Golgi apparatus (GA), endoplasmic reticulum (ER) and vacuolar machinery, in order to prepare for a subsequent round of prey capture. Tubular continuum between ER and Golgi stacks observed on ZIO-impregnated tissues may correspond to an efficient transfer mechanism for lipids and/or proteins, especially for use in rapidly resetting the molecular GA machinery. The occurrence of one vacuolar continuum may permit continuous adjustment of cell homeostasy. The subcellular features of the secretory cells of Dionaea muscipula outline key innovations in the organisation of plant cell compartmentalisation that are used to cope with specific cell needs such as the full use of the GA as a protein factory, and the ability to create protein reservoirs in the periplasmic space. Shape-derived forces of the pleiomorphic vacuole may act as signals to accompany the sorting and entering flows of the cell.     

关于新疆热电厂职业危害分析与讨论

对比不同热电厂企业工人接触职业危害因素情况,分析原因,为在建或已建热电厂提供职业危害因素预防措施,降低企业由于设计、施工或管理方面原因造成后期运行过程中职业危害接触超标情况的发生。根据我室历年对新疆地区热电厂职业危害因素检测结果与评价报告的比较,找出不同热电厂职业病危害因素的共性及异性,分析不同设备、工艺及管理方式不同所造成职业危害因素检测结果的差异及原因。建议优化厂区工艺及土建设计;优化设备选型及原料选择运用现代化的管理手段,加强职业卫生管理体系宣贯的有效运作。     

高水电比重系统随机电力电量平衡模型与算法

针对高水电比重系统中电力电量平衡问题,首先考虑利用典型周负荷曲线进行电力电量平衡分析,以更好地计及工作日和非工作日不同的负荷曲线对可调水电站库容及火电站开机的影响。为恰当考虑风电场和光伏电站出力的不确定性和波动性,建立了基于随机优化的随机电力电量平衡模型,从概率的角度更好地分析和衡量风光电站对电量平衡的贡献。为方便该模型的求解,对非线性的水电转换函数进行线性化处理,得到混合整数规划模型,采用CPLEX对模型进行求解。以某高水电比重系统作为算例进行仿真分析,验证了所提随机电力电量平衡模型与算法的正确性和有效性,从概率的角度定量分析了风光电站的电量贡献。     

Effect of addition of corrosion inhibitors on corrosion behaviors of PCV material under diluted artificial seawater environment

ABSTRACT

Fukushima Daiichi nuclear power plants (1F) were damaged by unprecedented severe accident in the great east Japan earthquake, and seawater and freshwater had been injected as an emergency countermeasure for the core cooling. Although, the primary containment vessel (PCV) was not supposed to be exposed to diluted seawater, the PCV will be exposed to diluted seawater environment until fuel debris removal is completed. Therefore, it is necessary to establish a countermeasure of corrosion for the PCVs made of carbon steel. In this study, the effect of the addition of corrosion inhibitor, which is one of the corrosion countermeasures, was investigated by two types of corrosion tests. As a result of the immersion corrosion test, it was found that any of the three kinds of corrosion inhibitor could suppress corrosion of carbon steel. In addition, as a result of the inhibitor interim addition test, it was found that corrosion of carbon steel covered with corrosion products could be suppressed by optimizing the additive amount of corrosion inhibitor in the cooling water.