Utilization Prospects of Carbon Concentrate – a Product of Aluminium Smelting Carbon Dust Processing

2021 ◽  
Vol 25 (11) ◽  
pp. 12-17
Author(s):  
A.F. Shimanskii ◽  
V.N. Losev ◽  
O.V. Buyko ◽  
A.S. Yasinsky ◽  
Ya.V. Kazantsev ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Fluidized Bed ◽  
Combustion Method ◽  
Aluminum Production ◽  
Aluminium Smelting ◽  
Ash Residue

The possibilities of utilization of technogenic products of aluminum production: coal foam and carbon concentrate (СС) are considered. It is proposed to utilize CC in order to extract valuable components. The regularities of the utilization process of CC by the combustion method have been studied. It was found that the content of germanium in ash is determined by the temperature and the oxygen partial pressure in the system. Gallium is concentrated in ash in an amount of 0.8 wt.% during the combustion in a fluidized bed at a temperature of 1200 °C, the germanium extraction into sublimates reaches 90 %. The results of the leaching of gallium from the ash residue in acidic and basic media are presented; the maximum gallium extraction was 90 and 94 %, respectively.

scholarly journals The Gas Turbine Heat Exchanger in the Fluidized Bed Combustor

1982 ◽  
Author(s):  
C. F. Holt ◽  
A. A. Boiarski ◽  
H. E. Carlton
Keyword(s):  
Heat Exchanger ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Gas Turbine ◽  
Fluidized Bed ◽  
Development Program ◽  
Low Oxygen ◽  
Bed Temperature ◽  
Technical Effort ◽  
Fluidized Bed Combustor

In a current research and development program a coal fired atmospheric fluidized bed combustor is being designed to supply the heat to a closed cycle gas turbine cogeneration system. The major technical effort is directed towards the design of the in-bed heat exchanger, which is required to operate near bed temperature. This high temperature (850 C) exposes the heat exchanger tubes to potentially severe sulfidation. The corrosion behavior depends upon the intimate details of the bed environment and may be related to the occurrence of localized areas of low oxygen partial pressure and high sulfur partial pressure. This paper describes a series of measurements of oxygen partial pressure at various locations within a fluidized bed. The bed, containing densely packed heat exchanger tubes, was operated under various conditions to observe the effect of coal mixing and devolatilization on local oxygen activity. Substantial variations of oxygen partial pressure (below 10−14 atmospheres) were observed. It was noted that these locally severe variations could be substantially modified by changes in coal mixing (as through coal port design). The experiments with varying coal size suggest that rapid devolatilization is desirable and would reduce the extent of locally corrosive environments.

The Gas Turbine Heat Exchanger in the Fluidized Bed Combustor

1983 ◽  
Vol 105 (3) ◽  
pp. 438-445 ◽  
Author(s):  
C. F. Holt ◽  
A. A. Boiarski ◽  
H. E. Carlton
Keyword(s):  
Heat Exchanger ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Gas Turbine ◽  
Fluidized Bed ◽  
Development Program ◽  
Low Oxygen ◽  
Bed Temperature ◽  
Technical Effort ◽  
Fluidized Bed Combustor

In a current research and development program a coal-fired atmospheric fluidized bed combustor is being designed to supply the heat to a closed cycle gas turbine cogeneration system. The major technical effort is directed towards the design of the in-bed heat exchanger, which is required to operate near bed temperature. This high temperature (850° C) exposes the heat exchanger tubes to potentially severe sulfidation. The corrosion behavior depends upon the intimate details of the bed environment and may be related to the occurrence of localized areas of low oxygen partial pressure and high sulfur partial pressure. This paper describes a series of measurements of oxygen partial pressure at various locations within a fluidized bed. The bed, containing densely packed heat exchanger tubes, was operated under various conditions to observe the effect of coal mixing and devolatilization on local oxygen activity. Substantial variations of oxygen partial pressure (below 10−14 atmospheres) were observed. It was noted that these locally severe variations could be substantially modified by changes in coal mixing (as through coal port design). The experiments with varying coal size suggest that rapid devolatilization is desirable and would reduce the extent of locally corrosive environments.

scholarly journals The Corrosive Environment in the Fluidized-Bed Heat-Exchanger for CCGT Service

1983 ◽  
Author(s):  
M. A. Rocazella ◽  
I. G. Wright ◽  
C. F. Holt
Keyword(s):  
Heat Exchanger ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Fluidized Bed ◽  
Mechanical Damage ◽  
Oxygen Probe ◽  
Erosion Process ◽  
Bed Material ◽  
Fluidized Bed Combustor

Corrosion and combustion diagnostic data were gathered in Battelle’s 0.6m diameter coal-fired atmospheric fluidized-bed combustor (AFBC). Corrosion probes, constructed from ring specimens of candidate heat-exchanger alloys, were exposed to the fluidized-bed environment during three different combustion experiments (50%, 20% and 0% excess air). An in-situ oxygen probe was used to monitor the oxygen partial pressure at the exposure locations. Two different mechanisms of material degradation were identified, i.e., both corrosion and erosion. An adherent deposit of bed material formed on all areas of the corrosion probes. The corrosion behavior of the alloys beneath the deposit, and the corresponding corrosion product morphologies, appeared to correlate well with predictions based on the oxygen partial pressure measurements from the exposure location. The results suggest the oxygen probe may be a useful diagnostic tool for locating regions with high corrosive potentials. However, the upstream faces of the corrosion probes were subjected to enhanced mechanical damage, and this periodic removal of both the deposit and corrosion products resulted in significantly more metal degradation. Also, this corrosion/erosion process may locally deplete the alloy in chromium, leaving it susceptible to severe sulfidation and/or accelerated oxidation. It was suggested that these locations would be the first to experience heat-exchanger tube failure, and the coupled corrosion/erosion process would be the failure mechanism.

scholarly journals Effect of Hot-Dip Galvanizing Process on Selective Oxidation and Galvanizability of Medium Manganese Steel for Automotive Application

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1265
Author(s):  
Zhang Chen ◽  
Yanlin He ◽  
Weisen Zheng ◽  
Hua Wang ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Surface Oxidation ◽  
Steel Sample ◽  
Dew Point ◽  
Manganese Steel ◽  
Automotive Application ◽  
Stable Phase ◽  
Annealing Atmosphere ◽  
Medium Manganese Steel

A medium manganese steel with 7.5 wt.% Mn for automobile application was galvanized in a continuous Hot Dip Galvanizing (HDG) simulator under different galvanizing conditions. It was shown that the effects of dew point, annealing temperature and annealing atmosphere on the surface oxidation of steel could be comprehensively evaluated by the consideration of oxygen partial pressure P(O2). Although Mn2SiO4 was a thermodynamic stable phase when P(O2) varied from 10−28 to 10−21 atm, it was difficult to form Mn–Si–O composite oxide because there was no enrichment of silicon on the steel surface. So, this oxide was generally formed in the Fe substrate and had little effect on the galvanizability. With the increase in P(O2) above 10−25 atm, MnO particles in the form of the thermodynamic stable phase became coarser and tended to aggregate, which hindered the formation of a continuous inhibition layer, resulting in the defects of bare spots on the galvanized surface of the steel. When the oxygen partial pressure greater than 10−22 atm, film-like MnO layer was formed on the surface of steel sample, which obviously deteriorated the galvanizability. The galvanizability of the steel can be improved by the regulation of oxygen partial pressure; based on this, the reasonable zinc plating process parameters can be developed.

Quantitative evaluation of the oxidation behavior of ZrB2-15 vol.%SiC at a low oxygen partial pressure

Vacuum ◽  
2013 ◽  
Vol 88 ◽  
pp. 98-102 ◽  
Author(s):  
Ai Momozawa ◽  
Rong Tu ◽  
Takashi Goto ◽  
Yuuki Kubota ◽  
Hiroshi Hatta ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Quantitative Evaluation ◽  
Oxidation Behavior ◽  
Low Oxygen
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