"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

RESEARCH OF COMPLEX MODIFICATION OF HEAVY CONCRETE

2021 ◽  
Vol 96 (4) ◽  
pp. 107-112
Author(s):  
YU.S. FILIMONOVA ◽  
◽  
E.G. VELICHKO ◽  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Complex Chemical ◽  
Composition And Structure ◽  
Combined Use ◽  
Mineral Additive

Modification of the composition and structure of heavy concrete with the use of a complex chemical-mineral additive consisting of fly ash from thermal power plants, a superplasticizer, a high-valence hardening accelerator AC and a fine-dispersed clinker component is considered. Modified concrete is characterized by an increase in compressive strength at a brand age by 67%, a decrease in the water content of a concrete mixture by 13.6% and an improvement in its workability by 11-12 cm. With the combined use of a superplasticizer and a high-valence hardening accelerator AC a significant synergistic effect is observed in the format of enhancing their plasticizing effect. The high efficiency of the application of the mixed-dispersed clinker component has been established.

Unburned carbon in the circulating fluidised bed boiler fly ash

2011 ◽  
Vol 32 (4) ◽  
pp. 255-266 ◽  
Author(s):  
Rafał Kobyłecki
Keyword(s):  
Fly Ash ◽  
Separation Efficiency ◽  
Unburned Carbon ◽  
Fuel Particle ◽  
Fluidised Bed ◽  
Bed Temperature ◽  
Grid Design ◽  
Cfbc Fly Ash ◽  
Boiler Fly Ash ◽  
Circulating Fluidised Bed

Unburned carbon in the circulating fluidised bed boiler fly ash The paper describes the results of various actions and industrial tests conducted in order to decrease the content of unburned carbon in the fly ash of a circulating fluidised bed combustor (CFBC). Several attempts to improve the situation were made and the effects of several parameters on the unburned carbon content in the fly ash were investigated (e.g. bed temperature, cyclone separation efficiency, fuel particle size distribution, boiler hydrodynamics, grid design, and fuel data). Unfortunately, no satisfactory solution to these problems was found. Probably, apart from attrition and char fragmentation, additional factors also contributed to the formation of unburned carbon in the CFBC fly ash.

scholarly journals Characteristics of high carbon ash as a raw material for spontaneous combustion inhibitor and its field demonstration

2020 ◽  
Author(s):  
Seok Un Park ◽  
Jae Kwan Kim ◽  
Dong Ik Shin
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Bituminous Coal ◽  
Spontaneous Combustion ◽  
Bottom Ash ◽  
Frequency Factor ◽  
Raw Material ◽  
Unburned Carbon ◽  
Mixing Ratio ◽  
High Carbon

Abstract In this study, we examined the physical chemistry, fuel characteristics and combustion reactivity of high carbon ash as a raw material for spontaneous combustion inhibitor in order to solve the problem of spontaneous combustion which has been often occurring in coal yard of coal-fired power plants in Korea. The high carbon ash has higher activation energy and lower frequency factor than bituminous coal, so combustion began at a relatively higher temperature than bituminous coal. In case of fly ash, the heat transfer characteristics were better than those of bottom ash and pond ash, and in case of coarse particles of fly ash, they were found to be highly applicable as a raw material for spontaneous combustion inhibitor due to their relatively high unburned carbon content. As a result of manufacturing spontaneous combustion inhibitors along with asphalt and PFAD (palm fatty acid distillate), the contact angle to water was more than 90° regardless of the mixing ratio, showing hydrophobic surface characteristics, and it was found that the hardness and viscosity of spontaneous combustion inhibitors increased as the mixing ratio of high carbon ash increased. In addition, when spontaneous combustion inhibitors manufactured were applied to coal stockpiles in coal yard at coal-fired power plants, there was little change in the internal temperature of coal stockpiles and the highest value of instantaneous increasing rate per minute was found to be lowered from 1.60°C/min to 0.061°C/min, indicating that spontaneous combustion inhibitors using high carbon coal ash had a great effect of preventing spontaneous combustion.

Improvement in Recuperative Gas Cycles by Means of a Heat Generator Partly By-Passing the Recuperator: Application to Open and Closed Cycles and to Various Kinds of Energy

1979 ◽  
Author(s):  
Z. P. Tilliette ◽  
B. Pierre
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Primary Energy ◽  
Operating Conditions ◽  
Heat Output ◽  
Medium Temperature ◽  
Heat Generator ◽  
High Temperature Process ◽  
Temperature Heat ◽  
Operation Flexibility

A particular arrangement applicable to open or closed recuperative gas cycles, consisting of a heat generator partly by-passing the low pressure side of the recuperator, is proven to enhance the advantages of gas cycles for energy production. In this way, the cogeneration of both power with high efficiency owing to the recuperator and high temperature process heat becomes possible and economically attractive. Furthermore, additional possibilities appear for power generation by combined gas and steam or ammonia cycles. In any case, the overall utilitization coefficient of the primary energy is increased and the combined production of low or medium temperature heat can also be improved. The great operation flexibility of the system for combined energy generation is worth being emphasized: the by-pass arrangement involves no significant change in the operating conditions of the main turbocompressor as the heat output varies. Applications of this arrangement are made to open and closed gas cycle power plants using fossil, nuclear and solar energies. The overall heat conversion efficiency is tentatively estimated in order to appreciate the energy conversion capability of the investigated power plants.

Development of High Efficiency MCFC/GT Hybrid Power Generation System

2003 ◽  
Author(s):  
T. Watanabe ◽  
Y. Izaki ◽  
Y. Mugikura ◽  
M. Yoshikawa ◽  
H. Morita ◽  
...  
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Low Voltage ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Estimation Methods ◽  
Central Research ◽  
Molten Carbonate ◽  
Initial Development ◽  
Hybrid Power

A number of cycle simulations, which are applied by Molten Carbonate Fuel Cell (MCFC) power plants combined with gas/steam turbines, prove that it is possible to design very highly efficient power plants. However, the stack performance, the operation technology and the performance estimation technology have not yet been established during the initial development stages. The Central Research Institute of Electric Power Industry (CRIEPI) has performed many cell and stack tests and has evaluated the performance under various operating conditions. The operation, performance analysis and estimation methods have been developed for various pressure ranges. Therefore, the accuracy of the plant power estimation has been improved immensely. CRIEPI has also proposed the application of a Li/Na electrolyte instead of a Li/K to achieve higher voltages and a longer stack life. A 10 kW-class short stack consisting of ten 1-m2 cells with a Li/Na electrolyte was operated for more than 10,000 hours, and a very low voltage decay rate was measured during the governmental program. Based on these accomplishments, field tests on small MCFC/GT (gas turbine) hybrid power plants with capacities of several hundred kW will be initiated in Japan throughout the next years.

On the experimental lead-cooled installation

2020 ◽  
pp. 185-192
Author(s):  
N. V. Aleksandrov ◽  
Ye. D. Blank ◽  
A. D. Kashtanov ◽  
V. V. Stepanov ◽  
V. V. Lemekhov ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
High Efficiency ◽  
High Reliability ◽  
Liquid Lead ◽  
Extensive Experience ◽  
Technical Parameters ◽  
Large Structures ◽  
Speed Up ◽  
Coolant Circulation

Extensive experience in operating nuclear power plants convincingly proves that fast liquid metal cooled reactors are among the most promising. The advantages of using liquid lead coolants in nuclear power industry are shown. In Russia, lately, much attention has been paid to the natural safety of fast reactors. At the stage of testing materials for components of reactor plants, a number of problems arose for basic systems. An experimental lead-cooled installation was developed for testing large structures, continuous monitoring and maintaining specified technical parameters. For reliable coolant circulation (lead coolant circulation speed up to 200 kg/s), a magnetohydrodynamic pump (MHD pump) has been developed, which is distinguished by high efficiency and reliability, it is also ease in operation and maintenance. Currently, the experimental setup is successfully used in scientific research of materials for RU BREST-OD-300. All its systems showed high reliability, maintainability and the possibility of further modernization.

scholarly journals Ash as an alternative source of raw materials

2018 ◽  
Vol 60 ◽  
pp. 00026
Author(s):  
Olena Svietkina ◽  
Hanna Tarasova ◽  
Olha Netiaha ◽  
Svitlana Lysytska
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
Raw Materials ◽  
Thermal Power ◽  
Physical And Mechanical Properties ◽  
Particle Morphology ◽  
Optical Methods ◽  
Unburned Carbon ◽  
Alternative Source ◽  
Metallurgical Processes

The objective of the work is to study the aluminosilicate fractionation from fly ash, physical and mechanical properties of fly ash derived from the Thermal Power Plants (TPP) wastes. Ash, carbon concentrate (unburned carbon), ash concentrate and products of their treatment with reagents were tested by optical methods. The particle morphology of the objects of research was studied with the scanning electron microscope REM-100. The composition of the ash phases was investigated using the X-ray diffractometer DRON-2. A dispersed analysis of the TPP fly ash suggests a conclusion that it is advisable to separate particles of a narrow grain-size class within the range from 40 to 150 μm with an ash content of about 33%. The first product may be enriched by flotation method. Such a coal product may be used as a reducing medium in metallurgical processes, agglomeration, etc. The calorific capacitance of the concentrate is about 6000 kcal/kg (25000 kJ/kg).

Coal Fly Ash as a Dual Site Material for Cr(VI) Adsorption: Comparation between Single Site and Dual Site Isotherm Models

2015 ◽  
Vol 1101 ◽  
pp. 149-152
Author(s):  
Widi Astuti ◽  
Triastuti Sulistyaningsih ◽  
Dewi Selvia Fardhyanti
Keyword(s):  
Fly Ash ◽  
Active Sites ◽  
Power Plants ◽  
Coal Fly Ash ◽  
Thermal Power ◽  
Single Site ◽  
Unburned Carbon ◽  
Isotherm Models ◽  
Equilibrium Data ◽  
Dual Site

The major problem in coal-based thermal power plants is related to solid waste called coal fly ash (CFA). CFA is mainly composed of some oxides including SiO2, Al2O3 having active site and unburned carbon as a mesopore that enables it to act as a dual site adsorbent for heavy metals including Cr (VI). To get different characters of dual site, CFA was treated by sulfuric acid (H2SO4) at different concentrations, temperatures and reaction time. Furthermore, treated CFA were used as an adsorbent to adsorb Cr (VI) in aqueous solutions. Equilibrium data were evaluated by single site and dual site isotherm models. It can be concluded, although unburned carbon contributes on the Cr (VI) adsorption, the existence of unburned carbon decreases the amount of Cr (VI) adsorbed because unburned carbon can plug active sites where dominant adsorption occurs. However, dual site isotherm model yielded excellent fit with equilibrium data.

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