Nitric acid cycle process for extracting thermal energy from low-level heat sources

Nature ◽  
1978 ◽  
Vol 273 (5657) ◽  
pp. 25-27 ◽  
Author(s):  
N. Wakao ◽  
K. Nojo
Keyword(s):  
Nitric Acid ◽  
Thermal Energy ◽  
Heat Sources ◽  
Acid Cycle ◽  
Low Level

scholarly journals CHEMICAL REACTION CYCLES FOR THE RECOVERY OF LOW-LEVEL THERMAL ENERGY

1977 ◽  
Vol 10 (3) ◽  
pp. 224-228 ◽  
Author(s):  
SHIGETAKA FUJII ◽  
HIDEO KAMEYAMA ◽  
KUNIO YOSHIDA ◽  
DAIZO KUNII
Keyword(s):  
Chemical Reaction ◽  
Thermal Energy ◽  
Low Level ◽  
Reaction Cycles

scholarly journals Solution of Thermal Conductivity Problem of a Finite Dimensions Plate with Two Heat Sources

2021 ◽  
Vol 263 ◽  
pp. 03018
Author(s):  
Aleksandr Gulkanov ◽  
Konstantin Modestov ◽  
Sergey Usikov
Keyword(s):  
Thermal Energy ◽  
Heat Waves ◽  
Engineering Application ◽  
Critical Factor ◽  
Point Of View ◽  
Engineering Industry ◽  
Heat Sources ◽  
Practical Engineering ◽  
Air Conditioning Systems ◽  
Thermal Conductivity Problem

Research in the basic sciences is a critical factor in the development of the civil engineering industry. Solving the problems of radiation-convective heat transfer from heated surfaces has always aroused interest from the point of view of science and practical engineering application of knowledge. However, analytical solutions to these problems are obtained for elementary cases, for example, for infinite plates heated uniformly, or the propagation of heat waves in them obeys certain laws. The solution of the coupled problem of radiation-convective transfer from the surface of these panels is complicated not only by the geometric shape, but also by the openness of the entire thermophysical system, which includes the transfer of thermal energy from the coolant (coolant for cooling systems) to the surface of the thermal panel, from the panel to the room air by convection, and radiation to surrounding bodies (enclosing structures, furniture, people). In turn, additional heat exchange by convection occurs between the air and the enclosing structures. This article considers the possibility of obtaining an analytical solution to the problem of temperature distribution on the surface of a plate with two heat sources. When deriving the formulas, the classical equations of thermodynamics (Newton-Richmann, Fourier’s law, Helmholtz equation) were used. The general solution of the differential equation, in this case, is a linear combination of the Infeld and MacDonald functions. The research results can be applied to various areas of technical sciences: cooling of microprocessors, renewable sources of thermal energy, thermal and cooling panels for industrial production, automotive, marine shipbuilding, and of course heating and air conditioning systems for buildings and transport.

scholarly journals Calculation of the power of thermal energy consumed for heating the reactor of a bioenergy plant

2021 ◽  
Vol 264 ◽  
pp. 04069
Author(s):  
Nodira Imomova ◽  
Ochil Komilov ◽  
Jurabek Majitov ◽  
Jukhriddin Ergashov ◽  
Kamol Usmonov
Keyword(s):  
Power Consumption ◽  
Boundary Conditions ◽  
Heat Equation ◽  
Thermal Energy ◽  
Temperature Difference ◽  
Heat Sources ◽  
Additional Source ◽  
Additional Heat ◽  
Bioenergy Plant ◽  
Biogas Reactor

The issues of calculating the power of thermal energy consumed for heating biomass in the reactor of a bioenergy plant are considered. Based on the Fourier heat equation, a solution for the axisymmetric cylindrical problem under boundary conditions of the first kind is obtained, and the power of additional heat sources in a cylindrical biogas reactor is calculated. The influence of the height of the bioreactor and the temperature difference of the biomass on the power consumption of an additional source of thermal energy is analyzed

Study on Reduction of Liquid Waste From Reprocessing Plant by Electrolysis Process

2001 ◽  
Author(s):  
M. Shibuya ◽  
Y. Suzuki ◽  
H. Shimizu ◽  
M. Inoue ◽  
H. Kaneki ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Sodium Nitrate ◽  
Pilot Plant ◽  
Liquid Waste ◽  
Gas Composition ◽  
Storage Unit ◽  
Low Level ◽  
Engineering Study ◽  
Fundamental Research ◽  
Reprocessing Plant

Abstract The reduction of radioactive waste volume is an important issue for the management of the nuclear fuel cycle. The purpose of this study is to create a technique to drastically reduce low-level liquid waste generated by a spent fuel reprocessing plant employing PUREX technology. In the PUREX plant, NOx gas is used as an oxidizing reagent for adjustment of the Pu valence in the Pu purification stage. The spent NOx gas is recovered as nitric acid and a certain amount of recovered nitric acid becomes low-level waste (LLW). As NOx gas is produced by the chemical reaction of nitric acid and sodium nitrite, a considerable quantity of non-radioactive sodium nitrate solution is discharged. From the standpoint of the impact on the environment, this discharge must be reduced. The objective of this research is to develop an electrolysis process by which NOx gas is directly produced from recovered nitric acid. Using this technology, the low-level sodium nitrate waste can be reduced and the nonradioactive sodium nitrate waste from the present NOx production process can be entirely eliminated. The study was performed in the following two steps: Phase 1: Fundamental research; Phase 2: Engineering study. Fundamental research: A study on the conditions of nitric acid decomposition by electrolysis was performed. The composition of NO and NO2 and its quantity are determined by electrolyte concentration, cathode material and current density. Catholyte reduced electrochemically is in a state of chemical equilibrium expressed by NO, NO2 (N2O4), HNO2, HNO3 and H2O. Nitric acid concentration, temperature and partial pressure of NOx are important process parameters since NOx generation current efficiency and NOx gas composition are dependent on a chemical equilibrium. Engineering study: The pilot plant was designed and constructed. The process configuration of the pilot plant is the same as that of the anticipated actual plant and its NOx generation capacity is one eighth of the actual plant. The plant mainly consists of electrolysis unit, NOx compression and storage unit, sodium nitrite oxidation unit, nitric acid distillation unit, and NOx recovery and off-gas treatment unit. NOx gas and HNO2 are generated as a result of nitric acid reduction in the electrolysis unit. NOx gas is transported under negative pressure to the compression/storage unit by a compressor and is stored in tanks under high pressure. After adjustment of gas composition by O2 supply, NOx gas is fed to the user process in the case of an actual plant. In the pilot test plant, NOx gas is transported to the nitric acid recovery step, in which NOx gas is recovered as nitric acid and reused in the pilot plant. As a result of operation of the pilot plant, the process performance, equipment performance, and long-term operation stability were proven. It was confirmed through the pilot plant operation that this technology was immediately applicable to a PUREX reprocessing plant.

scholarly journals Efficiency of use of waste heat energy on the example of Chelyabinsk

2019 ◽  
Vol 140 ◽  
pp. 11003
Author(s):  
Grigoriy Tseyzer ◽  
Olga Ptashkina-Girina ◽  
Olga Guseva
Keyword(s):  
Thermal Energy ◽  
Waste Heat ◽  
Heat Pumps ◽  
Heat Output ◽  
Low Grade ◽  
Heat Sources ◽  
Sources Of Information ◽  
Equivalent Fuel ◽  
Low Grade Heat

We consider the possibility of improving the existing heat-suppling system in Chelyabinsk through the introduction of heat pump technology for the disposal of waste low-grade heat. Sources of information concerning the ways of utilization of waste thermal energy, the principles of work of heat pumps, classification of city sources of waste heat are analyzed. The technique directed to assess the effectiveness of applying heat pumps for each category of city sources of waste thermal energy is designed. The calculated assessment showed that the utilization of waste heat in the conditions of Chelyabinsk will reduce the annual energy of fuel consumption by 2.2 million tons of conventional fuel (24.9%). At the same time, thermal pollution will decrease by 1.5 million tons of equivalent fuel. This effect is possible with the use of heat pumps with a total heat output of 1,145 MW.

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