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[en] The invention is applied to a tritium extraction plant of for extraction of a hydrogen isotope for instance in a nuclear reactor on in reprocessing effluents. Heat extracted from vapors during cooling at the outlet of each isotopic exchange step is used for liquid vaporization and gas preheating at each inlet of isotopic exchange step
[fr]L'intervention s'applique a une installation d'extraction et/ou de production de tritium ainsi qu'a l'extraction d'un isotope de l'hydrogene. Ce procede est caracterise en ce qu'on recupere la chaleur extraite des phases vapeur et gazeuse lors du refroidissement a la sortie de chaque etage d'echange isotopique et en ce qu'on utilise la chaleur ainsi recuperee pour contribuer a la vaporisation du liquide et au prechauffage du gaz a l'entree d'un etage d'echange isotopique
[en] Heat transfer is a living science and technical advances are constantly being made. However, in many cases, progress is limited by the equipment that is available on the market, rather than by knowledge of the heat transfer process. A case in point is the design of economizers: in such equipment a small quantity of water (with a relatively good heat transfer coefficient) is heated by a large quantity of low-pressure gas (with an inherently low heat transfer coefficient). As a first step in design finned tubing is used to lessen the discrepancy in coefficients. From this point, it becomes apparent that the equipment consists of a small number of tubes (to maintain good velocity on the water side) of considerable length (to provide sufficient area). In the process industries the base pressure, though low, may be in the region of 0.5 bar, and there is no convenient flue in which to place the heat recovery coil. It is therefore contained in a flat-sided enclosure, which is ill-fitted to pressure containment and is therefore reinforced with a plethora of structural sections. Such inelegant construction is quite common in North America; in Europe, cylindrical containments of vast size have been supplied for the same purposes. The real shortcoming is a successful marriage of different disciplines to produce reliable and efficient heat transfer equipment suitably contained
[en] Heat transformers are a promising technology for optimal exploitation of waste heat streams. The use of heat transformers is efficient for energetic, exergetic, and economic reasons. Heat transformers are environment-friendly, and reduce both thermal pollution and the pollution by greenhouse gases. The practical use of heat transformers is however still limited to the water/LiBr pair. The application of new media and the multistage heat transformer are promising new developments. (A.S.)
[en] The heating of aluminium for profile forming involves high energy losses. Up to 50 percent of the energy is released into the atmosphere as waste heat. Two scientists of the Institute of Electrical Process Engineering of Leibniz University Hanover describe optimisation processes in the field of aluminium heating which have a high energy saving potential. (orig.)
[en] In this research, a vortex generator heat exchanger is used to recover exergy from the exhaust of an OM314 diesel engine. Twenty vortex generators with 30° angle of attack are used to increase the heat recovery as well as the low back pressure in the exhaust. The experiments are prepared for five engine loads (0, 20, 40, 60 and 80% of full load), two exhaust gases amount (50 and 100%) and four water mass flow rates (50, 40, 30 and 20 g/s). After a thermodynamical analysis on the obtained data, an optimization study based on Central Composite Design (CCD) is performed due to complex effect of engine loads and water mass flow rates on exergy recovery and irreversibility to reach the best operating condition. - Highlights: • A vortex generator heat exchanger is used for diesel exhaust heat recovery. • A thermodynamic analysis is performed for experimental data. • Exergy recovery, irreversibility are calculated in different exhaust gases amount. • Optimization study is performed using response surface method
[en] The purpose of this study is to predict the performance of an indirect evaporative cooling system, and to evaluate its energy saving effect when applied to the exhaust heat recovery system of an air-handling unit. We derive the performance correlation of the indirect evaporative cooling system using a plastic heat exchanger based on experimental data obtained in various conditions. We predict the variations in the performance of the system for various return and outdoor air conditioning systems using the obtained correlation. We also analyze the energy saving of the system realized by the exhaust heat recovery using the typical meteorological data for several cities in Korea. The average utilization rate of the sensible cooling system for the exhaust heat recovery is 44.3% during summer, while that of the evaporative cooling system is 96.7%. The energy saving of the evaporative cooling system is much higher compared to the sensible cooling system, and was about 3.89 times the value obtained in Seoul
[en] This paper gives a special focus on the role of outlet temperature of flue gas (T_g_o) in organic Rankine cycle (ORC) system for low temperature flue gas waste heat recovery. The variations of performance indicators: net work (W_n_e_t), exergy efficiency (η_e_x) and levelized energy cost (LEC) versus T_g_o are discussed. Considering the corrosion of low temperature flue gas, the necessity and reasonability of limiting T_g_o at its minimum allowed discharge temperature (355.15 K) are analyzed. Results show that there exist optimal T_g_o (T_g_o_,_o_p_t) for W_n_e_t and LEC, while T_g_o_,_o_p_t for η_e_x does not appear under the investigated range of T_g_o. Moreover, the T_g_o_,_o_p_t for W_n_e_t is always lower than 355.15 K, the T_g_o_,_o_p_t for LEC, despite being greater than the one for W_n_e_t, is just slightly higher than 355.15 K when the inlet temperature of flue gas varies from 408.15 K to 463.15 K. For the waste heat recovery of low temperature flue gas, it is reasonable to fix T_g_o at 355.15K if W_n_e_t or LEC is selected as primary performance indicator under the pinch point temperature difference of evaporator (ΔT_e) below 20K.
[en] Highlights: • A methodology for energy efficiency of large-scale chemical plants is developed. • A multi-level data extraction for energy requirement definition is introduced. • The practice of total site integration with the combination of levels is shown. • The suitable utilities are integrated and optimized for different proposals. • A Pareto analysis is performed to find the optimum combination of levels. - Abstract: This study presents a methodology based on process integration techniques to improve the energy efficiency of a large-scale chemical plant. The key to the approach is to represent the energy requirements with different heat transfer interfaces. Considering difficulties of data extraction for a large-scale plant, a multi-level data extraction scheme is introduced based on different heat transfer interfaces and includes five levels of growing complexity: black-box, grey-box, white-box, simple-model and detailed-model analysis. A combination of these levels instead of a single definition for the energy requirement has been applied on an industrial case study. Different steps of the approach are explained in detail and their potential are highlighted. The Single Process Integration (SPI) and Total Site Integration (TSI) has been performed and revealed that a higher potential of heat recovery could be driven through the TSI. The optimized site utility integration together with heat recovery improvement scenarios have considerably increased the energy saving potential in our case study. A multi-objective optimization has also been performed to find the optimum combination of units with different energy requirement levels. In conclusion, results from our case study have indicated that using a combination of different energy requirement levels will reduce the required modification of the actual site configuration
[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] Radiation recuperator is a class of indirect contact heat exchanger widely used for waste heat recovery in high temperature industrial applications. At higher temperatures heat loss is higher and as the cost of energy continues to rise, it becomes imperative to save energy and improve overall energy efficiency. In this light, a radiation recuperator becomes a key component in an energy recovery system with great potential for energy saving. Improving recuperator performance, durability, and its design and material considerations has been an ongoing concern. Recent progress in furnace design and micro turbine applications together with use of recuperators has resulted in reduced fuel consumption, increased cost effectiveness and short pay-back time periods. Due to its high commercial value and confidential nature of the industry, little information is available in the open literature as compared to convection recuperators where results are well documented. This review paper intends to bridge the gap in literature and provides valuable information on experimental and theoretical investigations in radiation recuperator development along with identification of some unresolved issues.