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[en] As a part of the project 'development of hydrogen production technologies by high temperature electrolysis using very high temperature reactor', we have developed an electrolyzer model for high temperature steam electrolysis (HTSE) system and carried out some preliminary estimations on the effects of heat recovery on the HTSE hydrogen production system. To produce massive hydrogen by using nuclear energy, the HTSE process is one of the promising technologies with sulfur-iodine and hybrid sulfur process. The HTSE produces hydrogen through electrochemical reaction within the solid oxide electrolysis cell (SOEC), which is a reverse reaction of solid oxide fuel cell (SOFC). The HTSE system generally operates in the temperature range of 700∼900 .deg. C. Advantages of HTSE hydrogen production are (a) clean hydrogen production from water without carbon oxide emission, (b) synergy effect due to using the current SOFC technology and (c) higher thermal efficiency of system when it is coupled nuclear reactor. Since the HTSE system operates over 700 .deg. C, the use of heat recovery is an important consideration for higher efficiency. In this paper, four different heat recovery configurations for the HTSE system have been investigated and estimated
[en] Description of solid sanitary and technogenic waste reprocessing technology; heat diagram of heat recovery of waste reprocessing process; description of facility operation fundamental modes; requirements to basic systems and materials of facility of technogenic and sanitary industrial waste high-temperature reprocessing; standard-technical documents according to which facility designing, building and operation is conducted are presented in the report. There have been demonstrated the capability for creation of facility of high-temperature sanitary and technogenic waste recovery. There have been selected structure materials with operation lifetime of not less than 10 years at the parameters obtained in the furnace. There have been shown that systems of heat-sink cooling with sodium coolant created in atomic energetic are applicable for heat recovery of melting furnace and outgoing gases in high-temperature sanitary and technogenic waste reprocessing facilities with bubbling flux bath
[en] The thermal process of wastes with higher calorific value by pyrolysis is reviewed to recover the value added three by-products; a pyrolytic char, a pyrolytic oil, and a non-condensable gas. These by-products from pyrolysis of the waste is converted for electricity power and thermal energy thru gasification process as well as waste heat recovery process. The energy resource and several processes in the integrated pyrolysis gasification combined cycle for waste treatment are investigated with the conceptual design in using the obtained operation data from the pyrolysis pilot, demonstration and commercial plant.
[en] This paper describes the 'crud' measurements performed during the Embalse nuclear power plant's thermal cycle for a power of 100% (645 MWe) under different purification conditions. The aim of this work is to optimize the four steam generators' tube plate cleaning in function of the sweeping produced by their purification. (Author)
[en] One of the most popular and feasible strategies to reduce costs for electrical and other energy supply in remote communities is the development of wind-diesel systems. In these systems, a significant share of the electrical energy requirements of a community can be provided by wind turbines connected to the community electrical distribution system. One of the characteristics of the systems having a relatively large ratio of wind turbine capacity to community load, called High Penetration Wind-Diesel Systems (HPWDS), is that during high wind periods there will be electrical energy available in excess of the net load on the system. An important concept of the HPWDS strategy is that this excess energy can be directed to a practical use, such as heating. The concept of HPWDS was shown to be economically and technically feasible in communities having no heat recovery on the diesel plants. It proved to be even more attractive as a strategy for self sufficiency of electrical supply in communities with waste heat recovery. 1 fig., 1 tab
[en] Processes and technologies to produce hydrogen synergistically by the steam reforming reaction using fossil fuels and nuclear heat are reviewed. Formulas of chemical reactions, required heats for reactions, saving of fuel consumption or reduction of carbon dioxide emission, possible processes and other prospects are examined for such fossil fuels as natural gas, petroleum and coal. The 'membrane reformer' steam reforming with recirculation of reaction products in a closed loop configuration is considered to be the most advantageous among various synergistic hydrogen production methods. Typical merits of this method are: nuclear heat supply at medium temperature below 600 deg. C, compact plant size and membrane area for hydrogen production, efficient conversion of feed fuel, appreciable reduction of carbon dioxide emission, high purity hydrogen without any additional process, and ease of separating carbon dioxide for future sequestration requirements. With all these benefits, the synergistic production of hydrogen by membrane reformer using fossil fuels and nuclear energy can be an effective solution in this century for the world which has to use. fossil fuels any way to some extent while reducing carbon dioxide emission. For both the fossil fuels industry and the nuclear industry, which are under constraint of resource, environment and economy, this production method will be a viable symbiosis strategy for the coming hydrogen economy era. (author)
[en] The application of large gas turbines to combined cycles for power production has increased significantly in the past ten years. Heat Recovery Steam Generators for large power plant applications have been developed to meet utility customer needs for compressed delivery and installation schedules, compliance with present and future emissions requirements, dispatchability, ruggedness and maintainability. This paper discusses design features of the current generation of HRSGs that promote modular shop assembly, minimum field erection, and characteristics that provide the ability to perform in quick start-up and daily cycle service
[en] Heat recovery steam generators (HRSGs) are responsible for more and more of the steam generating capacity of many utilities. Unfortunately, they are also increasingly responsible for the number of tube failures in the system. Corrosion that leads to failures often begins before commissioning and is exacerbated by cycling operation. This article reviews common waterside failure mechanisms in HRSGs, where they occur, and what can be done to prevent failures in the future. (orig.)
[en] Small gas turbines in power range of several MWs are quite suitable for application in distributed generation as well as Community Energy Systems (CES). Humidification is an effective way to improve gas turbine performance, and steam injection is the most general and practically feasible method. This study intended to examine the effect of steam injection on the performance of several MW class gas turbines. A primary concern is given to the regenerative cycle gas turbine. The steam injection effect on the performance of a system without the regenerator (i.e. a simple cycle) is also examined. In addition, the influence of bypass of some of the exhaust gas on the performance of the gas turbine, especially the regenerative cycle gas turbine, is evaluated.