Round-Robin Study of Leaching Methods as Applied to Solid Wastes from Coal-Fired Power Plants

2009 ◽  
pp. 112-112-18
Author(s):  
IP Murarka
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lokesh Kumar ◽  
Susanta Kumar Jana

Abstract Sulfur dioxide is considered as an extremely harmful and toxic substance among the air pollutants emitted from the lignite- and other high-sulfur-coal based power plants, old tires processing units, smelters, and many other process industries. Various types of absorbents and desulfurization technologies have been developed and adopted by the industries to reduce the emission rate of SO2 gas. The present paper focuses on the ongoing advances in the development of varieties of regenerative and non-regenerative absorbents viz., Ca-based, Mg-based, Fe-based, Na-based, N2-based, and others along with various FGD technology, viz., wet, dry or semi-dry processes. Additionally, different types of contactors viz., packed column, jet column, spray tower, and slurry bubble columns along with their significant operational and design features have also been discussed. In the existing or newly installed limestone-based FGD plants, an increasing trend of the utilization of newly developed technologies such as limestone forced oxidation (LSFO) and magnesium-enhanced lime (MEL) are being used at an increasing rate. However, the development of low-cost sorbents, particularly suitable solid wastes, for the abatement of SO2 emission needs to be explored sincerely. Many such wastes cause air pollution by way of entrainment of fine particulate matter (PM), groundwater contamination by its leaching, or brings damage to crops due to its spreading onto the cultivation land. One such pollutant is marble waste and in this work, this has been suggested as a suitable substitute to limestone and cost-effective sorbent for the desulfurization of flue gases. The product of this process being sellable in the market or may be used as a raw material in several industries, it can also prove to be an important route of recycling and reuse of one of the air and water-polluting solid wastes.


Author(s):  
Nickolas J. Themelis

This report presents the results of a study that examined alternatives to landfilling the municipal solid wastes (MSW) of New York City. Detailed characterization of the wastes led to their classification, according to materials properties and inherent value, to “recyclable”, “compostable”, “combustible”, and “landfillable”. The results showed that the present rates of recycling (16.6%) and combustion (12.4%) in New York City can be increased by a) implementing an automated, modern Materials Recovery Facility (MRF) that separates the blue bag stream to “recyclables” and “combustibles”, and b) combusting the non-recyclable materials in a Waste-to-Energy (WTE) facility. Combustion of wastes to produce electricity is environmentally much preferable to landfilling. An advanced technology for combustion is that used in a modern Waste-to-Energy plant (SEMASS, Massachusetts) that processes 0.9 million metric tons of MSW per year, generates a net of 610 kWh per metric ton of MSW, recovers ferrous and non-ferrous metals, and has lower emissions than many coal-fired power plants.


2014 ◽  
Vol 692 ◽  
pp. 74-79
Author(s):  
Feng Dai ◽  
Yan Chao Chen ◽  
Jiao Fan ◽  
Xiao Dan Guo

The comprehensive utilization of solid emissions from power plants has arose much attention in recent years. This paper first studied the present situation of the thermal power enterprise solid emissions market in China. Then by taking China Datang Tongzhou Technology Company as an example, its strengths, weaknesses, opportunities and threats were analyzed. Finally, based on the SWOT analysis, this paper put forward the effective methods to enhance the comprehensive utilization of solid wastes as well as the future development strategy of the company.


2020 ◽  
Vol 12 (21) ◽  
pp. 9026
Author(s):  
Ali Mohammadi ◽  
G. Venkatesh ◽  
Maria Sandberg ◽  
Samieh Eskandari ◽  
Stephen Joseph ◽  
...  

Hydrothermal carbonization (HTC) has been seen as a potentially beneficial process for converting wet biomass into value-added products. It is, however, necessary to overcome the challenges associated with handling the powdered form of hydrochar—a solid product of the HTC process—by controlling the formation of dust and facilitating smoother transportation and distribution in a potentially wide marketplace. In this paper, the authors investigate the environmental consequences of different alternatives for using hydrochar pellets produced from mixed sludges from pulp and paper mills in Sweden, using the environmental life cycle assessment (E-LCA). Two scenarios for possible end-uses of hydrochar in combined heat and power (CHP) plants as a source of energy (heat and electricity) were assessed. In these scenarios, hydrochar pellets were assumed to be combusted in CHP plants, thereby avoiding the use of combustible solid wastes (Scenario A) and coal (Scenario B), respectively, to recover energy in the form of electricity and heat. The environmental damages to Human Health, Ecosystem Quality, Climate Change, and Resources are evaluated based on 1 tonne of dry sludge as the functional unit. The results from this analysis illustrate that Scenario B, in which hydrochar replaces coal, offers the greatest reduction in all the environmental damage characterizations, except the Resources category. The displacement of energy-based coal due to hydrochar combustion contributed most significantly to the environmental damages wrought by the system—ranging from 52% in Resources to 93% in Ecosystem Quality. Overall, the results highlight that the application of hydrochar pellets for energy recovery to offset waste- and coal-based energy sources has great environmental benefits. The favorability of sludge hydrochar over solid wastes as fuel for CHP plants may be counter-intuitive at first, since HTC is an energy-intensive process, but when accounting for the necessity of dependence on imports of wastes for instance, the hydrochar pellet may well emerge as a good option for CHPs in Sweden.


2013 ◽  
Vol 753-755 ◽  
pp. 628-631
Author(s):  
Zhi Xin Yue ◽  
Juan Nong Chen

Fly ash is a large amount of solid wastes produced from power plants, use of its resources has always been a matter of the government and experts are concerned. Combining with the characteristics of the nature of the fly ash, introduces the fly ash resource utilization in construction materials using some new approaches and application of the status quo.


Author(s):  
Steven D. Toteda

Zirconia oxygen sensors, in such applications as power plants and automobiles, generally utilize platinum electrodes for the catalytic reaction of dissociating O2 at the surface. The microstructure of the platinum electrode defines the resulting electrical response. The electrode must be porous enough to allow the oxygen to reach the zirconia surface while still remaining electrically continuous. At low sintering temperatures, the platinum is highly porous and fine grained. The platinum particles sinter together as the firing temperatures are increased. As the sintering temperatures are raised even further, the surface of the platinum begins to facet with lower energy surfaces. These microstructural changes can be seen in Figures 1 and 2, but the goal of the work is to characterize the microstructure by its fractal dimension and then relate the fractal dimension to the electrical response. The sensors were fabricated from zirconia powder stabilized in the cubic phase with 8 mol% percent yttria. Each substrate was sintered for 14 hours at 1200°C. The resulting zirconia pellets, 13mm in diameter and 2mm in thickness, were roughly 97 to 98 percent of theoretical density. The Engelhard #6082 platinum paste was applied to the zirconia disks after they were mechanically polished ( diamond). The electrodes were then sintered at temperatures ranging from 600°C to 1000°C. Each sensor was tested to determine the impedance response from 1Hz to 5,000Hz. These frequencies correspond to the electrode at the test temperature of 600°C.


Author(s):  
John D. Rubio

The degradation of steam generator tubing at nuclear power plants has become an important problem for the electric utilities generating nuclear power. The material used for the tubing, Inconel 600, has been found to be succeptible to intergranular attack (IGA). IGA is the selective dissolution of material along its grain boundaries. The author believes that the sensitivity of Inconel 600 to IGA can be minimized by homogenizing the near-surface region using ion implantation. The collisions between the implanted ions and the atoms in the grain boundary region would displace the atoms and thus effectively smear the grain boundary.To determine the validity of this hypothesis, an Inconel 600 sample was implanted with 100kV N2+ ions to a dose of 1x1016 ions/cm2 and electrolytically etched in a 5% Nital solution at 5V for 20 seconds. The etched sample was then examined using a JEOL JSM25S scanning electron microscope.


Author(s):  
Marjorie B. Bauman ◽  
Richard F. Pain ◽  
Harold P. Van Cott ◽  
Margery K. Davidson

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