Possibilities of Reducing the Apparent Porosity of Silica Bricks for the Coke Batteries

2014 ◽  
Vol 897 ◽  
pp. 121-124
Author(s):  
Lenka Nevřivová ◽  
Miroslav Kotouček ◽  
Karel Lang
Keyword(s):  
Compaction Pressure ◽  
Coke Oven ◽  
Coke Battery ◽  
Apparent Porosity ◽  
Point Of View ◽  
Repeated Heating ◽  
Heating And Cooling ◽  
Arc Furnaces ◽  
Coke Ovens ◽  
Coke Batteries

Silica is used for lining of the upper parts of glass furnaces and their regenerators and for lining of the lids of arc furnaces and for the coke oven batteries construction. Silica bricks represent 60% of refractory material used for a coke battery construction. Coke ovens are generally the largest oven aggregates, where silica material is used. The whole coke oven battery may reach the length up to 80 m due to the chamber sizes. A single coke oven battery contains up to 50.000 tons of refractories [1]. From the material science point of view, the durability of silica bricks depends on numerous parameters including first of all porosity and mineral composition. Microstructure of silica bricks changes during their application due to the heat load, repeated heating and cooling, and direct contact with the oven atmosphere. The paper discusses the possibility of reducing the apparent porosity and increasing of bulk density of coke oven silica bricks. It describes the effects of an iron dust, microsilica and influence of the compaction pressure on the coke oven silica microstructure. Functional characteristics of the material prepared according to the new standard recipes are compared with the properties of standard silica products.

scholarly journals Application of the method determining the pressure of the spreading coal and blends, as a method of extending the life of coke oven batteries

2019 ◽  
Vol 119 ◽  
pp. 98-106
Author(s):  
A. V. Sytnik
Keyword(s):  
Coke Oven ◽  
Raw Material ◽  
Bursting Pressure ◽  
Material Base ◽  
Coal Blend ◽  
Coke Ovens ◽  
Standard Value ◽  
Coke Batteries ◽  
Refractory Masonry ◽  
Selection Of

The analysis the state of coke batteries was carried out, with the help of which the main types of masonry wear the coke oven heating walls were established. The dynamics and nature of the damage suggest that for batteries with a long service life an individual approach is needed, both in the choice of the technological mode and in the selection of the raw material base coking, taking into account the pressure magnitude of coking blend. Since, in the process of coking coal blends, one the external manifestations of this process is a development of pressure expansion to the walls of coke oven chambers, when calculating the strength of coke ovens, the pressure of 7 kPa is taken as the critical pressure expansion. Exceeding this value leads to an increase in amperage and drilling of furnaces during the coke delivery of, premature wear of the refractory masonry, which requires more frequent repairs, and in extreme cases, deformation the walls of coking chambers. Therefore, coal blend, it is necessary to compile, taking into account not only the production of coke with the necessary mechanical strength, but also ensuring a bursting pressure not exceeding the standard value. To do this, in a laboratory setting to determine the pressure expansion, it is necessary to classify the incoming coal concentrates according to the indicator of pressure expansion, in order to compile blends with a safe value of pressure expansion.

POTOMAC

Alloy Digest ◽  
1975 ◽  
Vol 24 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Heat Treating ◽  
General Purpose ◽  
Low Carbon ◽  
Repeated Heating ◽  
Temperature Changes ◽  
Heating And Cooling ◽  
Temperature Performance ◽  
Heat Checking

Abstract POTOMAC is a general-purpose, low-carbon, chromium-molybdenum-tungsten hot-work steel. It has excellent resistance to shock and heat checking after repeated heating and cooling. Potomac is suitable for hot-work applications involving severe conditions of shock and sudden temperature changes. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-290. Producer or source: Allegheny Ludlum Corporation.

scholarly journals Planned redesign of beehive coke ovens for pollution control and power generation

2021 ◽  
Vol 69 (1) ◽  
pp. 25
Author(s):  
Binay Kumar Samanta ◽  
Manish Kumar Jain
Keyword(s):  
Pollution Control ◽  
Power Plants ◽  
Waste Heat ◽  
Thermal Power ◽  
Coal Tar ◽  
Coke Oven ◽  
Small Scale ◽  
Suspended Particulate ◽  
Wet Scrubbing ◽  
Coke Ovens

Fossil fuel based thermal power or ovens not only exude greenhouse gases and pollutants but transfer enormous amount of waste heat up in air. Heat gets enveloped in the stratosphere and circulate around the earth; escalating global warming. France, Czech Republic, Slovakia, Austria, Andorra, Luxembourg, Poland and Germany made it the hottest June on record in 2019. Around 50 coke ovens around Dhanbad are losing and facing closure, with fate of employees doomed. Jharkhand State Pollution Control Board, Dhanbad had been issuing letters to the small-scale refractory and beehive hard coke-ovens to bring down stack gas emissions to below 150mg/Nm3 of suspended particulate matter (SPM), equivalent to the standards of large thermal power plants, deploying electrostatic precipitators (ESP). Some locally made pollution control devices were deployed, but these reduced the chimney draft and coking time increased. Installation of wet scrubbing methods would not be economic and slow down production. With experience as the Manager of a by-product coke oven, the chimney detour method with mechanical exhauster suggested for beehive coke oven. Proposed design not only can generate power, but also trap pollutants by a kind of wet scrubbing and produce byproducts like coal tar. Various associations of small-scale hard coke ovens and refractory industries had approached The Institution of Engineers (India), Dhanbad Local Centre. In this paper, the authors briefly present how waste heat can be converted to power, while absorbing pollutants in hydraulic main in the unique chimney detour method and producing coal tar, exuding clean gas.

scholarly journals Formation of Incrustations during the Cocombustion of Biomass in Fluidised Bed Boilers

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Petr Buryan
Keyword(s):  
Raw Materials ◽  
Combustion Process ◽  
Power Equipment ◽  
Fluidised Bed ◽  
Boiler Furnace ◽  
Repeated Heating ◽  
Equipment Operation ◽  
Heating And Cooling ◽  
First Pass ◽  
Pass Through

In this article, we focus on causes of formation of incrustations in fluidised bed boilers that result from combustion of biomass-containing energy-producing raw materials and can significantly limit the efficiency of the respective power equipment operation. We applied laboratory procedures followed for assessment of characteristic eutectics of mixtures of coal ashes, desulphurisation components (dolomite and limestone), and woodchip ashes. Our analysis proved that combustion of these (or similar) raw materials, accompanied by repeated heating and cooling of combustion and flue gas desulphurisation products, leads to the formation of unfavourable incrustations. These incrustations can grow up to several tens of centimetres in size, thereby significantly restricting the power equipment functionality. They arise due to incrust reheating that results in the formation of eutectics, which have lower melting temperatures than that during their first pass through the combustion process. The same holds for desulphuriation components themselves. Formation of these new eutectics can be attributed both to recycling of substances produced during the first pass through the furnace as well as to mixtures formed both from recycled materials and from components initially combusted in the boiler furnace.

scholarly journals Analytical Modeling of Residual Stress in Laser Powder Bed Fusion Considering Part’s Boundary Condition

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 337 ◽  
Author(s):  
Elham Mirkoohi ◽  
Hong-Chuong Tran ◽  
Yu-Lung Lo ◽  
You-Cheng Chang ◽  
Hung-Yu Lin ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Kinematic Hardening ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Repeated Heating ◽  
Powder Bed ◽  
Heating And Cooling ◽  
Body Load ◽  
Point Body

Rapid and accurate prediction of residual stress in metal additive manufacturing processes is of great importance to guarantee the quality of the fabricated part to be used in a mission-critical application in the aerospace, automotive, and medical industries. Experimentations and numerical modeling of residual stress however are valuable but expensive and time-consuming. Thus, a fully coupled thermomechanical analytical model is proposed to predict residual stress of the additively manufactured parts rapidly and accurately. A moving point heat source approach is used to predict the temperature field by considering the effects of scan strategies, heat loss at part’s boundaries, and energy needed for solid-state phase transformation. Due to the high-temperature gradient in this process, the part experiences a high amount of thermal stress which may exceed the yield strength of the material. The thermal stress is obtained using Green’s function of stresses due to the point body load. The Johnson–Cook flow stress model is used to predict the yield surface of the part under repeated heating and cooling. As a result of the cyclic heating and cooling and the fact that the material is yielded, the residual stress build-up is precited using incremental plasticity and kinematic hardening behavior of the metal according to the property of volume invariance in plastic deformation in coupling with the equilibrium and compatibility conditions. Experimental measurement of residual stress was conducted using X-ray diffraction on the fabricated IN718 built via laser powder bed fusion to validate the proposed model.

The Influence of Process Parameters on Microstructure and Mechanical Properties of PM Al+4 wt. %Cu Alloy

2016 ◽  
Vol 682 ◽  
pp. 252-258
Author(s):  
Anna Tylek ◽  
Beata Leszczyńska-Madej ◽  
Albert Zygiert
Keyword(s):  
Process Parameters ◽  
Bending Strength ◽  
Compaction Pressure ◽  
Substantial Effect ◽  
Nitrogen Atmosphere ◽  
Point Of View ◽  
Pressing Pressure ◽  
Influence Of Process Parameters ◽  
Single Action ◽  
Three Point Bend Test

Attempts have been made to describe the influence of the process parameters, such as compaction pressure and sintering atmosphere on the microstructure and properties of PM Al4Cu alloy. Homogenous mixtures of Al4Cu elemental powders were achieved by tumbling powders for 30 minutes in the Turbula T2F mixer. The powders were subsequently cold compacted under pressures of: 200MPa, 300MPa and 400MPa in a rigid die on a single action press. The green compacts were sintered in two different atmosphere - nitrogen and vacuum at 600°C for one hour. After that, the samples sintered in nitrogen atmosphere were re-pressed and re-sintered (2p2s) under the same conditions. The green compact and as-sintered densities were measured using the geometric method. Additionally, the Brinell hardness and the bending strength in three point bend test were determined. The microstructure of the samples was also analyzed using both the light microscopy (LM) and scanning electron microscopy (SEM).The obtained results show, that optimal pressing pressure is 300MPa. Increasing pressure to 400 MPa has not a substantial effect on increase of the final sample density. Therefore applying higher compaction pressure (over 300MPa), from the economical point of view, is unnecessary.

scholarly journals Influence of Various Process Parameters on the Density of Sintered Aluminium Alloys

10.14311/1604 ◽  
2012 ◽  
Vol 52 (4) ◽  
Author(s):  
Mateusz Laska ◽  
Jan Kazior
Keyword(s):  
Sintered Density ◽  
Sintering Temperature ◽  
Compaction Pressure ◽  
Nitrogen Atmosphere ◽  
Chemical Compositions ◽  
Green Density ◽  
Heating And Cooling ◽  
Wide Range ◽  
Different Temperatures ◽  
Metallurgy Industry

This paper presents the results of density measurements carried out on Alumix sintered parts. ECKA Alumix aluminium powders were used because of their wide application in the powder metallurgy industry. The compacts were produced using a wide range of compaction pressures for three different chemical compositions. The compacts were then sintered under a pure dry nitrogen atmosphere at three different temperatures. The heating and cooling rates were the same throughout the entire test. The results showed that the green density increases with compaction pressure, but that sintered density is independent of green density (compaction pressure) for each sintering temperature.

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